Alginate

According to the World Health Organization, more than 374 million people worldwide suffer from diabetes. These people usually have to resort to supplements of insulin they must be administered on a regular basis. Tissue engineering provides a new approach to solving health problems, including diabetes. However, there are several considerations to take into account. Before addressing these considerations, it is necessary to have a basic knowledge about the structure and functioning of the organ responsible for regulating blood glucose; pancreas.

This knowledge will include a review of the anatomy and histology of the pancreas to understand how the tissue is organized. It will also include a brief development on their physiology, to better understand how it performs its function. Finally, the pathologies related to an altered function of this gland will be named.

The first consideration is the origin of these cells. Due to the lack of human donors, it has resorted to other ways of obtaining cells capable of secreting insulin. One way is to extract them from other mammals with similar human characteristic (such as pigs). Other alternatives are the use of pluripotent stem cells or implantation of insulin secretion-related genes by gene therapy in other body cells.

In addition to the source of the cells, it is also important to consider the response the body develops in the presence of foreign bodies. This encourages the development of protection and support structures to allow implementation of certain cells form and that they can perform their functions normally for long periods of time. You are structure are known as capsules and fall into two broad categories: macrocapsules and microcapsules. Today the main developments in this area focus on the creation of microcapsules because of the advantages they present.

The last consideration to be addressed in this paper is about that proper implementation of these cells, considering the optimal site of implantation for the best answer. methods are also considered for such implementation. Finally, it is important to analyze how the body responds to the implants to know the possible effects these have on the body.

The realization of this work allowed to better know the terminology and symbols on the subject, as well as technical issues to consider, for easier use in future works related to the topic.

A dressing is a sterile pad or compress applied to a wound to promote healing and protect the wound from further damage. Wounds are defined as self healing process but chronic wounds needs better handling and care from different parameters like moist conditions, application of herbs biocompatibility, and microbial infections. Wound dressing gives excellent wound healing than conventional/ traditional wound dressing. Some of the examples are Hydrogels, hydrocolloid, mapilex foam, etc. Traditional wound dressing is used to treat minor injuries like cuts. Eg: Normal saline and guaze. Several studies have documented the use of plant extracts for development of bioactive wound dressing. This review focuses on bioactive substances, natural and modified polysaccharides, proteins and synthetic materials in wound dressing for wound healing. Ideal wound dressing should achieve the wound healing with less time and cost. Significance of synthetic polymer films, foam dressing, hydrocolloids, hydrogels, and alginate dressing and their properties conforming the wound healing have been reviewed. Plant derived compounds which have anti-inflammatory, anti-microbial, high levels of antioxidants could be benefited for wound healing. Vegetal and bee products such as honey, Propolis and many more used in wound dressing as a bioactive substance is also discussed.

Çeşitli türlerdeki kahverengi deniz yosunlarından elde edilen alginatların en önemli özellikleri; jelleşme yetenekleri ve yüksek absorbsiyon kapasiteleridir. Alginatlar, endüstriyel uygulamalarda çok amaçlı olarak kullanılabilen malzemelerdir. En yaygın kullanım alanları tekstil baskıcılığı ve gıda endüstrisidir. Alginatın lif formuna getirilmesi yaş çekim prosesi ile gerçekleştirilir. Koagülasyon banyosunun içeriği elde edilecek alginat lifinin tipini belirlemektedir. Alginat liflerinin ıslak mukavemetlerinin oldukça düşük olması bir dezavantaj oluştururken, bilinen en higroskopik lif olması önemli avantajlar sağlamaktadır. Alginat lifleri, yüksek nem emme özelliği, iyon değişimi yeteneği, lif formundaki materyalin mükemmel biyouyumluluğu, kolay elde edilebilen doğal bir malzeme oluşu ve yara iyileşmesini kolaylaştıran spesifik özellikleri sayesinde son 20 yıldır yara bakım endüstrisinde önemli bir yer tutan ve olumlu etkileri bilinen bir malzemedir. Alginat lifleri, özellikle yüksek absorbent yara örtülerinin üretiminde faydalı bir hammaddedir. Alginatlar ve alginat lifleri hakkında literatür araştırması niteliğindeki bu çalışmada; alginatların üretimi, fizikokimyasal yapısı, özellikleri ve kullanım alanlarının yanı sıra alginattan lif eldesi, alginat liflerinin özellikleri ve kullanım alanları yer almaktadır.

Penelitian ini bertujuan untuk mengetahui metode presipitasi dalam ekstraksi yang terbaik berdasarkan mutu natrium alginat hasil ekstraksi dari Sargassum muticum dan Sargassum fluitans dari Alor, Nusa Tenggara Timur beserta biaya ekstraksinya. Parameter mutu yang diamati meliputi rendemen (%), viskositas (cP), derajat putih (%), kadar air (%), kadar abu (%), pH, dan FTIR. Hasil penelitian ini menunjukkan bahwa rendemen, viskositas, derajat putih, kadar air, kadar abu, dan pH natrium alginat hasil ekstraksi berkisar antara 9.34 ± 0.35 – 12.68 ± 0.28 %; 52.30 ± 1.47 – 127.17 ± 11.54 cP; 60.61 ± 0.87 – 77.31 ± 3.60 %; 6.50 ± 0.95 – 11.71 ± 0.59 %; 19.85 ± 0.41 – 21.88 ± 0.41 %; dan 7.07 ± 1.47 – 7.40 ± 0.10. FTIR menunjukkan bahwa natrium alginat hasil ekstraksi memiliki gugus fungsi yang mirip bahkan sama dengan natrium alginat komersial. Berdasarkan mutu viskositas natrium alginat dan biaya ekstraksinya, natrium alginat hasil ekstraksi dari Sargassum muticum dan Sargassum fluitans dengan metode presipitasi asam alginat termodifikasi lebih baik dibandingkan metode presipitasi asam alginat. Berdasarkan mutu viskositas dan derajat putih natrium alginat hasil ekstraksi dari Sargassum muticum dan Sargassum fluitans dengan menggunakan metode presipitasi asam alginat termasuk kategori mutu alginat food grade dan menggunakan metode presipitasi asam alginat termodifikasi termasuk kategori mutu alginat industrial grade.

Makroalga mengandung senyawa alginat yang dapat digunakan dalam berbagai bidang industri. Alginat dapat diekstraksi dari makroalga dengan metode filtrasi dalam bentuk cake. Aspek yang dapat diperhatikan dari alginat secara khusus adalah specific cake resistance. Hal ini dapat mempengaruhi proses filtrasi, khususnya dari segi waktu filtrasi. Dalam mengoptimalkan proses filtrasi, diperlukan analisis neraca massa agar dapat diimplementasikan dengan kondisi operasi yang diinginkan. Simulasi sederhana proses filtrasi dengan menggunakan unit rotary vacuum filter pada perangkat lunak SuperPro Designer® digunakan dalam menentukan scale-up proses filtrasi pada unit tersebut. Analisis neraca massa menunjukkan bahwa cake yang dihasilkan memiliki perolehan alginat sebesar 77.35% dengan kemurnian 25.1%. Pemodelan specific cake resistance didapatkan melalui persamaan ln(𝛼)=5,956+ln⁡(𝑡/𝜇) Simulasi scale-up proses filtrasi pada RVF dilakukan dengan memberikan peningkatan pada laju alir masukan sebesar 1000 kali dalam waktu 330 hari dalam setahun, dapat menghasilkan natrium alginat sebesar 747.386,64 ton/tahun. Hasil tersebut disertai dengan peningkatan luas area filter menjadi 1043,3141 m², serta perolehan (yield) sebesar 77,35% dan tingkat kemurnian (purity) sebesar 25,098%.

A B S T R A C T The toxic liver impairment caused by free radical injury or excessive reactive oxigen species (ROS) formation could be effectivelly attenuated by natural antioxidants. The present study aimed to explore and compare the hepatoprotective and antioxidant effects of free and encapsulated quercetin in in vitro and in vivo models of hepatotoxicity. Thus, quercetin was encapsulated in chitosan/alginate nanoparticles by gelation method. Both empty and quercetin-loaded nanoparticles revealed good safety profile in vitro, determined by the lack of cytotoxicity in human hepatoma HepG2 cells. The pretreatment of HepG2 cells with encapsulated quercetin (10 mg/ml) significantly attenuated the decrease in cell viability in H 2 ? 2-induced oxidative stress (0.1 mM H 2 ? 2) , thus showing an effective in vitro protection. In vivo evaluation of the antioxidant and hepatoprotective potential of free and encapsulated quercetin was performed in a model of paracetamol À induced liver injury in male Wistar rats. The oral pretreatment with encapsulated quercetin (0.18 mg/kg b.w., 7 days) significantly diminished the increased levels of serum transaminases ALT and AST, attenuated the lipid peroxidation and restored the levels of gluthation (a marker of cell antioxidant defence system). The protective effects of quercetin encapsulated in chitosan-based nanoformulation were superior to those of free quercetin. The results of the study suggest that the encapsulation of quercetin in chitosan/alginate nanoformulations might represent an effective therapeutic approach against oxidative stress induced liver injury.

The main objective of the current research was to successfully employ the reducing and stabilizing
features of xanthan gum to synthesize nanosilver, then coating cotton fabrics with the net produced
nanosilver in order to obtain finished fabrics valuable in medical applications. Pre-hydrolyzed xanthan
gum was used to reduce Ag+ to Ag0 in nano size using a simple one-step rapid synthetic route. The reduction
step was followed up by measuring the concentration of reducing sugars eliminated in the reaction
medium. The optimum concentration of xanthan gum was 3 g/L to reduce 1 mmol/L Ag+, as 2.66
±
0.4 g/L
was the maximum concentration of reducing sugars obtained in the reaction. Transmission microscope
images show that the AgNPs are spherical in shape with mean size 9.1
±
4.8 nm. Cotton fabrics were then
coated with the produced AgNPs using pad-dry-cure method. Well dispersed layer from Ag0 on cotton
surface was showed under electron microscope. The biocidal activities of the coated fabrics were tested
against Staphylococcus aureus and showed excellent results for antibacterial even after 20 washing cycles.
This method has the advantage of not necessitating aggressive conditions such as the presence of organic
solvents to produce durable antibacterial cotton fabrics.

Diffusion coefficient of alginate microcapsules used in pancreatic islet transplantation, a method to cure type 1 diabetes Avid Najdahmadi, Jonathan R. T. Lakey, Elliot Botvinick Avid Najdahmadi, Jonathan R. T. Lakey, Elliot Botvinick, "Diffusion coefficient of alginate microcapsules used in pancreatic islet transplantation, a method to cure type 1 diabetes, Abstract: Pancreatic islet transplantation is a promising approach of providing insulin in type 1 diabetes. One strategy to protect islets from the host immune system is encapsulation within a porous biocompatible alginate membrane. This encapsulation provides mechanical support to the cells and allows selective diffusion of oxygen, nutrients and insulin while blocking immunoglobulins. These hydrogels form by diffusion of calcium ions into the polymer network and therefore they are highly sensitive to environmental changes and fluctuations in temperature. We investigated the effects of gel concentration, crosslinking time and ambient conditions on material permeability, volume, and rigidity, all of which may change the immunoisolating characteristics of alginate. To measure diffusion coefficient as a method to capture structural changes we studied the diffusion of fluorescently tagged dextrans of different molecular weight into the midplane of alginate microcapsules, the diffusion coefficient is then calculated by fitting observed fluorescence dynamics to the mathematical solution of 1-D diffusion into a sphere. These measurements were performed after incubation in different conditions as well as after an in vivo experiment in six immunocompetent mice for seven days. Additionally, the changes in gel volume after incubation at different temperatures and environmental conditions as well as changes in compression modulus of alginate gels during crosslinking were investigated. Our result show that increase of polymer concentration and crosslinking time leads to a decrease in volume and increase in compression modulus. Furthermore, we found that samples crosslinked and placed in physiological environment, experience an increase in volume. As expected, these volume changes affect diffusion rates of fluorescent dextrans, where volume expansion is correlated with higher calculated diffusion coefficient. This observation is critical to islet protection since higher permeability due to the expansion in vivo may lead to increased permeability to immunoglobulins. Capsules from the in vivo study showed similar volume expansion and increased permeability, indicating our in vitro assay is a good predictor of volume change in vivo.

a b s t r a c t a r t i c l e i n f o Malignant brain tumors including glioblastoma are incurable cancers. Over the last years a number of promising novel treatment approaches have been investigated including the application of inhibitors of receptor tyrosine kinases and downstream targets, immune-based therapies and anti-angiogenic agents. Unfortunately so far the major clinical trials in glioblastoma patients did not deliver clear clinical benefits. Systemic brain tumor therapy is seriously hampered by poor drug delivery to the brain. Although in glioblastoma, the blood brain barrier is disrupted in the tumor core, the major part of the tumor is largely protected by an intact blood brain barrier. Active cytotoxic compounds encapsulated into liposomes, micelles, and nanoparticles constitute novel treatment options because they can be designed to facilitate entry into the brain parenchyma. In the case of biological therapeutics, encapsulation of therapeutic cells and their implantation into the surgical cavity represents another promising approach. This technology provides long term release of the active compound at the tumor site and reduces side effects associated with systemic delivery. The proof of principle of encapsulated cell factories has been successfully demonstrated in experimental animal models and should pave the way for clinical application.

Özet: Kahverengi deniz yosunlarından elde edilen ve doğal bir biyopolimer olan alginatın elektro çekimindeki zorluklar henüz aşılamamıştır. Bu çalışmada, sodyum alginatın iki farklı konsantrasyondaki (%1 ve %2) sulu çözeltileri, biyouyumlu sentetik bir polimer olan poli (vinil alkol)'ün sulu çözeltisi ile karıştırılmıştır. Farklı hacim oranlarındaki poli (vinil alkol)/sodyum alginat karışım çözeltilerinden elektro çekim yöntemi ile nanolifli yüzeyler elde edilmiştir. Karışım çözeltilerine ait viskozite, yoğunluk, pH, elektrik iletkenliği ve yüzey gerilimi özellikleri tespit edildikten sonra elektro çekim yöntemi ile elde edilen yüzeyler, Taramalı Elektron Mikroskobu (SEM) ile analiz edilmiş, ortalama lif çapları hesaplanmıştır. Böylece, çözelti parametreleri ile nanolif çaplarının ve yüzey özelliklerinin ilişkilendirilmesi hedeflenmiştir. Gerçekleştirilen deneysel çalışma ile, sodyum alginatın %1'lik konsantrasyonunda daha başarılı elektro çekim sonuçları alındığı görülmüştür. Ayrıca, yüksek viskozite ve pH, düşük elektrik iletkenliği ve yüzey gerilimi değerleri ile dikkat çeken 2/1 karışım oranındaki %9 poli (vinil alkol) / %1 sodyum alginat çözeltisinin elektro çekiminden optimum sonuçların alındığı boncuksuz, üniform ve ultra ince nanolifler elde edilmiştir.

Abstract: Electrospinning of a natural biyopolymer alginate which is produced from brown seaweeds is still a challenge. In this study, aqueous solutions of sodium alginate (with concentrations of 1% and 2%) were blended with aqueous solution of, a biocompatible, synthetic polymer, poly (vinyl alcohol) (with concentration of 9%). Nanofibrous mats from poly (vinyl alcohol)/sodium alginate solution blends were produced in different volume ratios. After the determination of solution properties such as viscosity, density, electrical conductivity, pH and surface tension, electrospun alginate nanofibers were analyzed by using Scanning Electron Microscope (SEM) and average fiber diameters were measured. So, relationship between solution properties and fiber diameters, surface properties were investigated. During experimental studies it was observed that solution blends which consisted of 1% sodium alginate solution could be electrospun more successfully. Also, beadless, uniform, smooth, ultrafine fibers from the 2/1 solution blends of 9% poly (vinyl alcohol) / 1% sodium alginate, which had high viscosity and pH, low electrical conductivity and surface tension values were produced.

Adapting bottom-up approaches to tissue engineering is a real challenge. Since the first application of fused deposition modeling for tissue engineering scaffolds, considerable effort has been focused on printing synthetic biodegradable scaffolds. Concurrently a variety of rapid prototyping techniques have been developed to define macroscopically the shapes of deposited biomaterials, including photolithography, syringebased gel deposition, and solid freeform fabrication. These designed scaffolds have shown promise in regenerating tissues at least equivalent to other scaffolding methods.

PEMBENTUKAN SPONTAN KOMPLEK POLIELEKTROLIT FIBROIN SUTERA DENGAN ALGINAT SEBAGAI MODEL PENGHANTARAN OBAT (Gita Cahya Eka Darma) Fibroin Sutera (SF) dan Alginat (ALG) merupakan biomaterial yang memiliki efek terapeutik dalam pengobatan luka yaitu hemostatik, dan kemampuannya dalam menyerap eksudat luka. Agen terapetik alami memiliki banyak keunggulan daripada penggunaan obat sintetik kimiawi, sehingga menjadikannya sebagai alternatif pilihan yang baik dalam pengobatan. Penelitian ini bertujuan membuat model penghantaran untuk pengobatan luka yaitu berupa membran serat hasil kompleksasi polielektrolit (PEC) melalui metode koaservasi. SF dari kepompong ulat sutera (Bombyx mori Linn) digunakan sebagai agen polikation, ALG sebagai agen polianion dan Kloramfenikol (CHL) sebagai model obatnya. Karakterisasi membran serat PEC yang dilakukan meliputi analisis gugus fungsi (FTIR), derajat kristalinitas (XRD), sifat termal (DSC), mikroskopik (SEM). Kemudian, dilakukan perhitungan perolehan koaservat (coacervation yield), uji keabuhan (swelling), dan uji pelepasan CHL secara in‒vitro. SDS PAGE digunakan untuk mengidentifikasi protein. Penelitian ini telah menghasilkan SF dengan karakteristik baru yang lebih baik, sehingga diperoleh membran serat PEC yang sesuai sebagai model penghantaran untuk pengobatan luka pada kulit. Membran serat PEC merupakan hasil modifikasi dari koaservat SF‒ALG berbentuk hidrogel. SF dalam membran berada pada konformasi strukturnya yang stabil yaitu Silk II dengan derajat kristalinitas dari SF maupun ikat‒silang elektrostatik SF‒ALG yang baik, sehingga membran serat ini dapat mengembang atau larut bergantung pada pH sistem. Analisis karakteristik membran telah membuktikan bahwa terjadi ikat‒silang elektrostatik antara SF dengan ALG, bentuk polimorf serta derajat kristalinitas SF dan membran dapat dikendalikan sehingga menentukan hasil akhir membran. Membran serat PEC responsif terhadap kondisi keasaman sistem, pada pH < 3 membran mengembang sementara pH > 3‒5,5 membran melarut sehingga dapat disesuaikan dengan kondisi pH tempat pelepasannya. Profil keabuhan meningkat dari pH 1 menuju pH 3 dengan persentase paling rendah adalah 414,3% (F3) dan paling tinggi adalah 844,4% (F2). Profil pelepasan CHL dari F1‒F3 berturut-turut adalah 91,33; 98,88; 81,94% selama 30 menit. Pelepasan paling cepat diperoleh dari formula dengan jumlah ALG lebih besar, sebaliknya pada jumlah SF lebih besar maka pelepasannya lebih lama sehingga rasio ini dapat menentukan jenis pelepasan yang diinginkan. Kata kunci: Fibroin sutera, natrium alginat, koaservasi, komplek polielektrolit, membran serat -------------------------------------------------------------------------------------------------------------------------------------------
SELF-ASSEMBLED POLYELECTROLYTE COMPLEX OF SILK FIBROIN WITH ALGINATE AS DRUG DELIVERY MODEL (Gita Cahya Eka Darma) Silk Fibroin (SF) and Alginate (ALG) are biomaterial that have therapeutic efect in wound dressing which is hemostatic, and the ability upon absorption of wound exudates. Natural therapeutic agents has many advantages than the use of chemical synthetic drugs, so that making it a good alternative in the medication. This research aims to make delivery model for wounds dressing in the form of fiber membrane results from polyelectrolyte complexation (PEC) through coacervation method. SF from silkworm cocoons (Bombyx mori Linn) used as polycations agent, ALG as polyanions agent and Chloramphenicol (CHL) as drug model. Characterization of PEC fiber membranes are conducted with analysis of the functional groups (FTIR), crystallinity degree (XRD), thermal properties (DSC), microscopic (SEM). Then, the study continued to the measurement of coacervation yield, swelling test, and in-vitro drug release test. SDS PAGE was used to verify the protein. This research has gained SF with better new characteristics, in order to obtain the appropriate PEC fiber membrane as delivery models for the treatment of skin wounds. PEC fiber membrane is a modified version from hydrogel-forming of SF‒ALG coacervate. SF in the membrane is in the stable conformation structure (Silk II) with a proper cystallinity degrees of SF and the SF‒ALG electrostatic crosslinking, so this fiber membrane can swelling or dissolve depending on the pH of the system. Characterization analysis of the membrane shown that the electrostatic bonds occurs between SF with ALG, polymorphic forms of the protein fibroin and crystallinity degree of SF and membrane can be controlled to determine the final result of the membrane. PEC fiber membrane is responsive to pH, at pH < 3 swelling occurs while at pH > 3‒5,5 it dissolved, this condition could be adjusted to the pH condition of the site released. The swelling profile increased from pH 1 upto pH 3 with the lowest percentage is 414,3% (F3) and the highest is 844,4% (F2). The CHL release profile of F1‒F3 respectively are 91,33; 98,88; 81,94% during 30 minute. The fastest drug release profile obtained from the formula with a higher amount of ALG, and otherwise on the formula that SF amounts is higher then the release is slower, this ratio can determine the type of release as required. Keywords: Silk fibroin, sodium alginate, coacervation, polyelectrolyte complex, fiber membrane

Kelp harvesting has increased globally in recent decades and is expected to continue rising as the demand for kelp-derived products for use in aquaculture and industrial applications increases. In response, numerous studies have examined how harvesting impacts kelp populations and their associated communities, but the effects of repeated harvesting of the same individuals on the chemical properties for which they are extracted remain poorly understood. This knowledge gap may be especially crucial in areas where the same kelps are necessarily harvested multiple times per year due to their overall low abundance. To address this, we examined how repetitive harvesting of the same individuals of giant kelp, Macrocystis pyrifera, over a 3-month period influences tissue chemical properties (i.e. alginate yield, viscosity and strength, nutritional quality, such as protein, carbohydrate, lipid, crude fiber, ash and energy content, and tissue carbon/nitrogen ratios). Our results indicate that, while these properties vary over time, presumably due to variability in oceanographic conditions, repetitive harvesting of the same individuals does not significantly impact these properties.

Background: Chitosan and Alginate were used as biopolymers to prepare membranes for protein adsorption. The network requires a cross-linker able to form bridges between polymeric chains. Viscopearl-mini ® (VM) was used as a support to synthesize them. Six different types of membranes were prepared using the main compounds of the matrix: VM, Chitosan of low and medium molecular weight, and Alginate. Results: Experiments were carried out to analyze the interactions within the matrix and improvements were found against porous cellulose beads. SEM characterization showed dispersion in the compounds. According to TGA, thermal behaviour remains similar for all compounds. Mechanical tests demonstrate the modulus of the composites increases for all samples, with major impact on materials containing VM. The adsorption capacity results showed that with the removal of globular protein, as the adsorbed amount increased, the adsorption percentage of Myoglobin from Horse Heart (MHH) decreased. Molecular electrostatic potential studies of Chitosan-Alginate have been performed by density functional theory (DFT) and ONIOM calculations (Our own N-layered integrated molecular orbital and molecular mechanics) which model large molecules by defining two or three layers within the structure that are treated at different levels of accuracy, at B3LYP/6-31G(d) and PM6/6-31G(d) level of theory, using PCM (polarizable continuum model) solvation model. Conclusions: Finally, Viscopearl-mini ® acts as a suitable support on the matrix for the synthesis of Chitosan-Alginate membranes instead of cross-linkers usage. Therefore, it suggests that it is a promise material for potential applications, such as: biomedical, wastewater treatment, among others.

Resources are becoming scarce. Therefore, reuse of resources is becoming more and more attractive. Wastewater can be used as a resource, since it contains many resources like organic matter, phosphorus, nitrogen, heavy metals, thermal energy, etc. This study focused on the reuse of organic matter and phosphorus from Amsterdam's wastewater. There is a wide variety of possible alternatives, and the technical options are growing. The problem is not the availability of technology for resource recovery, but the lack of a planning and design methodology to identify and deploy the most sustainable solutions in a given context. To explore alternative, coherent and viable strategies regarding resource recovery from Ams-terdam's wastewater chain, the development process of dynamic adaptive policy pathways was used. In the first phase a material flow analysis was made for Amsterdam's wastewater chain and analyzed for water, organic matter and phosphorus. In the second phase measures were identified and characterized. The characterization was based on criteria focusing on changes in material flows, recovered products and implementation horizon. For the Amsterdam case recovered products concerned alginic acid, bioplastic, cellulose, phosphorus and biogas. In the third phase the measures were combined into strategies, which are combinations of measures that focus on a specific goal of resource recovery. For the Amsterdam case this resulted in four strategies: a strategy focusing on production of alginic acid, a strategy focusing on production of bioplastics, a strategy focusing on recovery of cellulose, and a strategy focusing on recovery of phosphorus. Adaptive policymaking showed to be a good approach to deal with the wide variety of possibilities and uncertainties. It resulted in a coherent policy as the resource recovery goals became clear, a flexible policy as the lock-in, no-regret and win-win measures could be identified, and an up-to-date policy as a periodic update is possible that will reveal new chances and risks.

In this study, sodium alginate (SA) hydrogel film incorporated with Manuka honey was successfully developed. Swelling properties and gel fraction of hydrogel films decreased upon addition of Manuka honey in SA film. SA hydrogel film has the highest swelling percentage at 512 ± 21% and decreased to 197 ± 9% in SA hydrogel film containing 10% (v/v) of Manuka honey (SA-H10). In contrast, the SA-H10 hydrogel film has the lowest gel fraction at 12 ± 1% compared to SA hydrogel film at 45 ± 3%. The Young's Modulus of SA hydrogel films with Manuka honey were increased as the concentrations of Manuka honey increased. The hydrogel films with higher concentration of Manuka honey (SA-H10) were soft with tensile strength, tensile strain and Young's Modulus at 1.06 ± 3 MPa, 15 ±1% and 34 ± 3 MPa, respectively. The water vapour transmission rates (WVTRs) of SA-H hydrogel films were in the range of 1051 ± 48 – 1428 ± 84 g m-2 d-1 , which comparable to WVTRs values with the commercial wound dressing products. The SA-H hydrogel films can be a potential material to be used as a wound dressing product.

This work deals with optimising the cell survival of rhizobacteria encapsulated in alginate beads filled with starch. Immobilisation of rhizobacteria was done by dripping alginate-starch solution mixed with rhizobac-teria into a calcium solution. Beads were analysed based on matrix formulation, bacteria growth phase, osmoprotectants and nature of calcium solution. Maximum cell recovery was obtained on Raoultella terrigena grown in medium supplemented with trehalose and calcium gluconate as gelling agent. Furthermore, dried beads containing Azospirillum brasilense presented 76% of viable cells after one year of storage. The survival of rhizobacteria during the bioencapsulation process can be improved by incorporating starch on beads composition, varying the growth phase of cells and using trehalose in growth culture medium. This work provides a selection of appropriate methods to improve the surviving rate of encapsulated cells during their production and long-term storage ($1 year at 4 C).

One important challenge in biomedicine is the ability to cryogenically preserve not only cells, but also tissue-engineered constructs. In the present paper, alginate-poly-l-lysine-alginate (APA) microcapsules containing erythropoietin (Epo)-secreting C(2)C(12) myoblasts were elaborated, characterized and tested both in vitro and in vivo. Dimethylsulfoxide (DMSO) was selected as cryoprotectant to evaluate the maintenance of physiological activity of cryopreserved microencapsulated myoblasts employing procedures based on freezing protocols up to a 45-day cryopreservation period. High chemical resistance of the cryopreserved microcapsules was observed using 10% DMSO as cryoprotectant following a standard slow-cooling procedure. Although a 42% reduction in Epo release from the microencapsulated cells was observed in comparison with the non-cryopreserved group, the in vivo biocompatibility and functionality of the encapsulated cells subcutaneously implanted in Balb/c mice was corroborated by high and sustained hematocrit levels over 194 days and lacking immunosuppressive protocols. No major host reaction was observed. Based on the results obtained in our study, a slow-cooling protocol using 10% DMSO as cryoprotectant (confirmed for cryopreservation periods up to 45 days) might be considered a suitable therapeutic strategy if the long-term storage of microencapsulated cells, such as C(2)C(12) myoblasts is pretended.

Investigations were made on the brown seaweed Sargassum polycystum C. Agardh collected from Rameswaram Coast, Tamil Nadu. The alginates extracted from 'leaf', 'stem' and entire thallus of S. polycystum were investigated for their viscosity and chemical constituents, namely β -D-mannuronic acid (M-block), α -L-guluronic acid (G-block) and alternating sequences of β -D-mannuronic acid and α -L-guluronic acid (MG-block) for six different seasons between August 1998 and November 1999. Significant seasonal variation ( P < 0.05) was observed with high yield of alginate in February. The alginate extracted from the 'leaf' region showed a maximum yield whereas the 'stem' region exhibited maximum viscosity. The amount of G-block was found to be more than M-and MG-blocks in all the samples tested. The amount of G-block was high in 'stem' followed by 'leaf' and entire thallus. A positive correlation was recorded between viscosity and G-block. Among the three alginates, the ratio of M/G was low in the 'stem' followed by 'leaf' and entire thallus.

In this study, potential of the alginate based electrospun nanofibrous mats as wound dressings was investigated macroscopically in vivo experiments. 2/1 (v/v) %9 PVA / %1 NaAlg nanofibrous mats were produced by electrospinning method. In order to improve water resistance of the electrospun mats, the cross-linking was performed. SEM analyses, thickness and air permeability tests were applied for the nanofibrous mats produced as wound dressing and Suprasorb-A commercial alginate wound dressing. In vivo experiments, the healing performances of the wounds dressed by using cotton gauze, Bactigras, Suprasorb-A and the electrospun PVA/NaAlg nanofibrous mat were macroscopically evaluated and compared. The wound healing potential of the electrospun mat was better than that of cotton gauze including a drug and looked like antibacterial Bactigras. The results indicated that the electrospun PVA/NaAlg nanofibrous mat as wound dressing provided a good means for wound healing. ÖZET Bu çalışmada, elektro çekim yöntemi ile elde edilen alginat nanolifli yüzeylerin yara örtüsü olarak kullanım potansiyeli, gerçekleştirilen in vivo çalışmalarla makroskobik olarak değerlendirilmiştir. 2/1 hacimsel karışım oranında %9 PVA / %1 NaAlg çözeltisinden elektro çekim yöntemi ile nanolifli yüzeyler üretilmiştir. Bu yüzeylerin suya dayanımını geliştirmek için, çapraz bağlama işlemi uygulanmıştır. Yara örtüsü olarak üretilen nanolifli yüzeylere ve ticari alginatlı yara örtüsü olan Suprasorb-A'ya SEM analizleri, kalınlık ve hava geçirgenliği testleri uygulanmıştır. In vivo çalışmalarda, gazlı bez, Bactigras, Suprasorb-A ve elektro çekim ile üretilen PVA/NaAlg nanolifli yüzey ile kapatılmış yaraların yara iyileştirme performansları makroskobik olarak değerlendirilmiş ve kıyaslanmıştır. Elektro çekim yöntemi ile üretilmiş yüzeyin yara iyileştirme potansiyeli; ilaç emdirilmiş gazlı bezden daha iyi, antibakteriyel bir örtü olan Bactigras ile benzer olmuştur. Sonuçlar, PVA/NaAlg nanolifli yüzeylerin yara örtüsü olarak kullanılabilir olduğu öngörüsünü doğrulamıştır.

In recent years nano-sized particles have been focused on bacteriostasis. We investigated antimicrobial activities by applying AgNPs–alginate composite on cotton fabric, using a simple one-step rapid synthetic route by reduction of silver nitrate using alkali hydrolyzed alginate solution which acts as both reducing and capping agent. FTIR spectra, color coordinates, silver content, silver release percent and SEM images of treated fabric samples confirmed the successful physical deposition of AgNPs–alginate composite on the fabric. The treated fabrics demonstrated an excellent antibacterial activity against the tested bacteria, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. A slight decrease in the antibacterial feature of the cotton fabrics was observed after successive washings. However, an efficient antibacterial activity still remained on the fabrics.

Microcapsules Stability Physiochemical factors Physiological factors a b s t r a c t Transplantation of microencapsulated cells has been proposed as a cure for many types of endocrine disorders. Alginate-based microcapsules have been used in many of the feasibility studied addressing cure of the endocrine disorders, and different cancer types. Despite years of intensive research it is still not completely understood which factors have to be controlled and documented for achieving adequate mechanical stability. Here we studied the strength and elasticity of microcapsules of different composition with and without cell load. We compared strength (force) versus elasticity (time) required to compress individual microcapsule to 60% deformation. It is demonstrated that the alginate viscosity, the size of the beads, the alginate type, the gelling time, the storage solution and the cell load are dominant factors in determining the final strength of alginate-based microcapsules while the type of gelling ion, the polyamino acid incubation time, the type of polyamino acid and the culturing time determines the elasticity of the alginate-based microcapsules. Our data underpin the essence of documenting the above mentioned factors in studies on encapsulated cells as mechanical stability is an essential factor in the success and failure of encapsulated grafts. (S.V. Bhujbal).

The alginate microspheres containing bovine serum albumin(BSA),chosen as a model protein,was prepared by spraying.The conditions of preparation were optimized by comparing the mean diameter of particles and the encapsulation efficiency of BSA.The results indicate that the encapsulation efficiency of BSA and the BSA loading are high(60% and 8%,respectively).The process of encapsulation has no effect on relative molecular mass,the molecular structure and the antigenicity of BSA by SDS-polyacrylamide gel electrophoresis(SDS-PAGE),Western-blot and circular dichroism(CD)spectrum.The in vitro release profile shows a controlled release of encapsulated BSA owing to the excellent pH responsive properties of alginate microspheres.Particularly in simulated gastric fluid,the release ratio and release amount of encapsulated BSA are low.Therefore,alginate microspheres are useful in intestinal-specific protein drugs delivery by protecting them from the destruction of gastric environment.

PURPOSE:
To investigate whether mesenchymal stem cells (MSCs) seeded in novel polyvinyl alcohol (PVA)-chitosan composite hydrogel can provide comparable or even further improve cartilage repair outcomes as compared to previously established alginate-transplanted models.
METHODS:
Medial femoral condyle defect was created in both knees of twenty-four mature New Zealand white rabbits, and the animals were divided into four groups containing six animals each. After 3 weeks, the right knees were transplanted with PVA-chitosan-MSC, PVA-chitosan scaffold alone, alginate-MSC construct or alginate alone. The left knee was kept as untreated control. Animals were killed at the end of 6 months after transplantation, and the cartilage repair was assessed through Brittberg morphological score, histological grading by O'Driscoll score and quantitative glycosaminoglycan analysis.
RESULTS:
Morphological and histological analyses showed significant (p < 0.05) tissue repair when treated with PVA-chitosan-MSC or alginate MSC as compared to the scaffold only and untreated control. In addition, safranin O staining and the glycosaminoglycan (GAG) content were significantly higher (p < 0.05) in MSC treatment groups than in scaffold-only or untreated control group. No significant difference was observed between the PVA-chitosan-MSC- and alginate-MSC-treated groups.
CONCLUSION:
PVA-chitosan hydrogel seeded with mesenchymal stem cells provides comparable treatment outcomes to that of previously established alginate-MSC construct implantation. This study supports the potential use of PVA-chitosan hydrogel seeded with MSCs for clinical use in cartilage repair such as traumatic injuries

Background and objectives: Recycled polyethylene terephthalate (RPET) nanofibers have become an important part of human life, with a continuous increase in their production and consumption. Herein, the antibacterial activity of nickel nanoparticles/recycled polyethylene terephthalate nanofibers (NiNP/RPET NF web) was evaluated by analyzing alginate expression in Pseudomonas aeruginosa, as an opportunistic microorganism. Methods: NiNPs were synthesized and NiNP/RPET NF was produced by adding 25 μg/ml of NiNP to 10% solutions of RPET at a weight ratio of 3%. After exposing P. aeruginosa (PA01) to NiNP/RPET NF, the biofilm-forming capacity was determined and realtime PCR was performed to measure algD expression. Results: Treatment with 25 μg/ml of NiNP/RPET NF reduced growth of P. aeruginosa on Mueller Hinton agar but did not result in complete inhibition. The biofilm optical density (550 nm) was 0.464 ± 0.021 after treatment with NiNP/RPET NF and 0.082± 0.011 in the absence of NiNP/RPET NF. This indicates the significant reduction of biofilm formation after exposure to NiNP/RPET NF (p=0.01). In addition, a 0.6-fold (p=0.03) reduction in alginate expression was detected by real-time quantitative real-time PCR. Conclusion: Our results indicate the potential of NiNP/RPET NF for application in nano-based antibacterial medical systems.

The effect of malic acid and essential oils (EOs) of cinnamon, palmarosa and lemongrass and their main active compounds as natural antimicrobial substances incorporated into an alginate-based edible coating on the shelf-life and safety of fresh-cut "Piel de Sapo" melon (Cucumis melo L.) was investigated. Melon pieces (50 g) were coated with alginate-based edible coating containing malic acid (EC) and EOs or their active compounds before to be packed in air filled polypropylene trays and stored at 5°C for shelf-life and sensory studies. On the other hand, melon pieces were inoculated with a Salmonella Enteritidis (10 8 CFU/ml) culture before applying the coatings containing malic acid and EOs or their active compounds to safety study. Controls of fresh-cut melon non-coated or coated with EC without EOs were also prepared. EC was effective to improve shelf-life of fresh-cut melon from microbiological (up to 9.6 days) and physicochemical (N 14 days) points of view in comparison with noncoated fresh-cut melon, where microbiological and physicochemical shelf-life was up to 3.6 days and lower than 14 days, respectively. In addition, the incorporation of EOs or their active compounds into the edible coating prolonged the microbiological shelf-life by more than 21 days in some cases due probably to an enhanced antimicrobial effect of malic acid + EOs; however, some fresh-cut melon characteristics were affected such as firmness and color causing a reduction of physicochemical shelf-life. Significant reductions (p b 0.05) of S. Enteritidis population in inoculated coated fresh-cut melon were achieved, varying the effectiveness of the coatings depending on the EOs or the active compound and their concentrations. According to the results, palmarosa oil incorporated at 0.3% into the coating appear to be a promising preservation alternative for fresh-cut melon, since it had a good acceptation by panellists, maintained the fruit quality parameters, inhibited the native flora growth and reduced S. Enteritidis population.

Chronic wounds represent a major public health issue, with an extremely high cost world-wide. In healthy individuals, the wound healing process takes place in different stages: inflammation, cell proliferation (fibroblasts and keratinocytes of the dermis), and finally remodeling of the extracellular matrix (equilibrium between metalloproteinases and their inhibitors). In chronic wounds, the chronic inflammation favors exudate persistence and bacterial film has a special importance in the dynamics of chronic inflammation in wounds that do not heal. Recent advances in biopolymer-based materials for wound healing highlight the performance of specific alginate forms. An ideal wound dressing should be adherent to the wound surface and not to the wound bed, it should also be non-antigenic, biocompatible, semi-permeable, biodegradable, elastic but resistant, and cost-effective. It has to give protection against bacterial, infectious, mechanical, and thermal agents, to modulate the level of...

Background
In the present study, the effects of alginate (ALG) concentration and ovarian cells (OCs) on the devel- opment and function of follicles were simultaneously evaluated.

Materials and Methods
In the first step of this experimental study, preantral follicles were isolated from the ovaries of 2-week-old mice, encapsulated in the absence or presence of OCs in 0.5, 0.75 and 1% ALG hydrogels, and cultured for 14 days. The morphology, diameter, survival and antrum formation rates of the follicles and the maturation of the oocytes were evaluated during culture. In the second step, preantral follicles were cultured in the best chosen ALG concentration, in both the absence and presence of OCs. Following these steps, the amount of DNA fragmentation, the expression levels of connexin 37 and connexin 43 proteins, the secretion levels of estradiol, progesterone and andros- tenedione by the follicles and the quality of mature (MII) oocytes were assessed.

Results
Our data revealed that in the absence of OCs, follicles of 0.5% group showed a higher survival rate than the 0.75 and 1% groups (71.87 vs. 52.52 and 40%, respectively, P<0.05). Nonetheless, the antrum formation rate of the 1% group was higher and its oocyte degeneration rate was lower than that in the other groups. Furthermore, it was observed that co-culture of follicles with OCs relatively increased the follicle diameter, survival, antrum formation, and germinal vesicle (GV) to GV break down (GVBD)/MII transition rates. At last, the comparison of 0.5%-OCs and 0.5%+OCs groups indicated that the co-culture condition resulted in more progesterone production (1.8 ± 0.2 vs. 3.2 ± 0.4 ng/ml, respectively, P<0.05) and also decreased oocytes’ cortical granule abnormalities (100 vs. 40% for 0.5%- OCs and 0.5%+OCs groups, respectively).

Conclusion
The present study revealed that 0.5% ALG hydrogel is relatively suitable for preantral follicle culture, and in the presence of OCs, it mimics the natural ovarian condition better than the higher concentrations of ALG hydrogel.

In most of the cases where conventional dosage forms are used, only a small amount of administered dose reaches the target site, while the majority of the drug distributes throughout the rest of the body in accordance with its biochemical properties. Therefore, one of the most attractive areas of research in drug delivery today is the design of nanosystems that are able to deliver drugs to the right place, at appropriate times and at the right dosage. The present study reports a novel strategy for the preparation of nanoparticles of alginate and chitosan by microemulsion crosslinking technique. Morphology and structural characterization of prepared nanoparticles were investigated by transmission electron microscope (TEM) analysis, and Fourier transform infrared spectra (FTIR), respectively. Nanoparticles were tested for cytotoxicity with human foreskin fibroblast (HFF) cells. The particles were allowed to swell in phosphate buffer saline (PBS) and the influence of factors such as chemical composition of nanoparticles; pH and temperature of swelling bath were studied on water sorption capacity of nanoparticles. The prepared nanoparticles could prove to be an excellent option as carrier for controlled and targeted delivery of anticancer drugs.

The effect of malic acid and essential oils (EOs) of cinnamon, palmarosa and lemongrass and their main active compounds as natural antimicrobial substances incorporated into an alginate-based edible coating on the shelf-life and safety of fresh-cut "Piel de Sapo" melon (Cucumis melo L.) was investigated. Melon pieces (50 g) were coated with alginate-based edible coating containing malic acid (EC) and EOs or their active compounds before to be packed in air filled polypropylene trays and stored at 5°C for shelf-life and sensory studies. On the other hand, melon pieces were inoculated with a Salmonella Enteritidis (10 8 CFU/ml) culture before applying the coatings containing malic acid and EOs or their active compounds to safety study. Controls of fresh-cut melon non-coated or coated with EC without EOs were also prepared. EC was effective to improve shelf-life of fresh-cut melon from microbiological (up to 9.6 days) and physicochemical (N 14 days) points of view in comparison with noncoated fresh-cut melon, where microbiological and physicochemical shelf-life was up to 3.6 days and lower than 14 days, respectively. In addition, the incorporation of EOs or their active compounds into the edible coating prolonged the microbiological shelf-life by more than 21 days in some cases due probably to an enhanced antimicrobial effect of malic acid + EOs; however, some fresh-cut melon characteristics were affected such as firmness and color causing a reduction of physicochemical shelf-life. Significant reductions (p b 0.05) of S. Enteritidis population in inoculated coated fresh-cut melon were achieved, varying the effectiveness of the coatings depending on the EOs or the active compound and their concentrations. According to the results, palmarosa oil incorporated at 0.3% into the coating appear to be a promising preservation alternative for fresh-cut melon, since it had a good acceptation by panellists, maintained the fruit quality parameters, inhibited the native flora growth and reduced S. Enteritidis population.

From recent studies on bone and shell formation, the importance of polysaccharides in biomineralization processes is gradually being recognized. Through ion-complex-ation and self-assembly properties, such macromolecules have remarkable effects on mineralization. However, their influences on the different regimes of crystallization including the interactions with precursor species are unclear. The present study therefore addresses calcium carbonate mineralization in the presence of alginates, a class of linear copolymeric saccharides composed of β-1,4 linked D-mannuronic and L-guluronic acid. During mineralization, this biopolymer is found to exert pH-dependent control over mineralization pathways in terms of the stability of prenucleation clusters, inhibitory effect toward nucleation and initially formed postnucleation products. Remarkably in the presence of this macromolecular additive, either amorphous or crystalline vaterite particles can be selectively nucleated in a pH-dependent manner. This is validated by electron microscopy wherein vaterite particles are intimately associated with alginate assemblies after nucleation at pH 9.75. At lower pH, aggregates of amorphous particles are formed. Thus, in addition to the general focus on biochemical properties of additives, solution pH, a physiologically fundamental parameter significantly alters the scheme of mineralization.

Sargassum brown algal species have recently shown promise for use in flow-through column systems that rely on a passive ion-exchange mechanism for the remediation of toxic heavy metals such as Pd, Cd, and Zn from contaminated waters. To elucidate the metal binding mechanism and optimise this so-called biosorption process, detailed information on the biochemistry of the raw biomass and the alginate in particular is essential. This study focuses on the detailed characterisation (e.g., percentage of yield, block co-polymer structure) of the various fractions of material isolated from S. fluitans and S. oligocystum following a (i) standard neutral, (ii) alkaline (NaOH) and (iii) high-temperature alkaline alginate (80 • C; Na 2 CO 3 ) extraction. Results indicate that the alginate yield was independent of the temperature or the extraction method employed (21.1 to 22.8% and 18.9 to 20.5% yields for S. fluitans and S. oligocystum, respectively). Furthermore, 1 H-nuclear magnetic resonance (NMR) analyses revealed that the alginates isolated by the three methods displayed nearly identical doublet α-L-guluronic acid frequencies (F GG ; between 0.55 to 0.58 for both S. fluitans and S. oligocystum). Cadmium binding experiments (pH 4.5) further demonstrated that the three alginate extracts have similar metal binding capacities (uptake ranging from 1.59 to 1.81 mmol Cd/gram). The implementation of the high-temperature alkaline extraction procedure resulted in the isolation of a new acid-soluble fraction (ASF), capable of binding cadmium at pH 4.5, which cannot be isolated by the standard neutral extraction protocol. A preliminary characterisation of this ASF revealed the presence of minor quantities of proteins and sulphated polysaccharides, as well as traces of alginate and possibly other low-molecular weight uronic acid-containing polymers.

Because of considerable interest in the preparation of biodegradable materials based on natural polymers, many techniques have been used to modify the physical and chemical properties of natural polymers. Due to the presence of various functional groups on molecular chains, polysaccharides could be readily modified chemically to form polymer hybrid of good composition and functional properties. There have been a number of studies reported for chemical attachments of synthetics polymers. However, grafting of vinyl monomers onto polysaccharides backbone via radical polymerization is often used technique. Alginic acid or alginate is polyuronides, i.e., polysaccharides in which the molecules are built up of uronic acid residues which are obtained from seaweed species of brown algae. Alginate has broad applications in various fields such as pharmaceutical, biomedical, agriculture, and environmental. The present review compiled the studies on the chemical modification of alginate via free-radical graft copolymerization, particularly by generating the free radicals using thermal initiator or electron transfer reaction (redox system) and the potential applications of the grafted copolymers.

Alginic acids are perspective biopolymers with significant application in food technologies and pharmaceuticals. The aim of the current research was to synthesized environment-friendly alginic acid derivatives (methylated and amidated alginic acids with the different ratio of M/G blocks in the polysaccharide backbone) by ultrasound irradiation. The newly synthesized derivatives were characterized by the degree of esterifi-cation (DE), degree of amidation (DA) and their structure were elucidated by FT-IR spectroscopy. Their physi-cochemical properties were also evaluated. Methyl esters of two alginic acids were characterized with DE 49 and 82 % respectively, while their amidated derivatives reached DA to 53 %. The methylated alginic acid with (M/G) ratio: 61:39 showed the promising results future application as a foaming agent. The obtained results showed the significant improvement of rheological properties of methylated alginates with increase of DE, and decrease of emulsifying properties after amidation of alginate methyl esters, respectively.