Research Articles by Dr. Sasikumar Swamiappan
Materials Chemistry Division, School of Advanced Sciences, VIT University Vellore -632 014, Tamil... more Materials Chemistry Division, School of Advanced Sciences, VIT University Vellore -632 014, Tamilnadu, India E-mail : [email protected] Bioceramic calcium silicates have evolved as a potential biomaterial for artificial bone and dental root implants due to its excellent bioactivity and improved mechanical strength hence in the present work we aimed to convert the bio-waste into a useful biomaterial. In this study diopside (<strong>CaMgSi<sub>2</sub>O<sub>6</sub></strong> ) has been successfully prepared by sol-gel combustion method by using L-alanine as a fuel, nitrate ions as an oxidiser and egg shell (chicken) as a calcium source. Optimization of calcination temperature resulted in a well crystalline diopside powders with high phase purity. Synthesized powders were characterized by powder-<strong>XRD</strong> for phase identification, <strong>FT-IR</strong> spectroscopy for functional group analysis and scanning electr...
School of Advanced Sciences, VIT University, Vellore-632 014, Tamilnadu, India E-mail : ssasikuma... more School of Advanced Sciences, VIT University, Vellore-632 014, Tamilnadu, India E-mail : [email protected] In this study, we have prepared bioactive sodium calcium silicate (<strong>SCS</strong>) powders from sodium carbonate, calcium nitrate, tetraethyl orthosilicate (<strong>TEOS</strong>) by sol-gel combustion method using citric acid as a fuel. Phase formation of the synthesized <strong>SCS</strong> powders was characterized by powder X-ray diffraction (<strong>XRD</strong>). Composites were prepared by adding different ratios of sodium calcium silicate powder to chitosan and their <em>in vitro</em> bioactivity was analyzed by immersing the composites in simulated body fluid (<strong>SBF</strong>) solution. Results show that more chitosan contain composite shows greater bioactivity when compared to the composites contains lesser chitosan. Estimation of calcium ion concentration in the <strong>SBF<...
kuwait journal of science, 2016
Calcium hydroxyapatite (Ca10(PO4)6(OH)2) was synthesized by Pechini method byusing citric acid an... more Calcium hydroxyapatite (Ca10(PO4)6(OH)2) was synthesized by Pechini method byusing citric acid and ethylene glycol as a complexing agent and gelling agent. Calciumnitrate and diammonium hydrogen phosphate were taken as the source of calciumand phosphate respectively. The as-prepared precursor and calcined products werecharacterized by powder X-ray diffraction (XRD) for phase identification, Fourier -Transform Infrared spectroscopy (FT-IR) for functional group analysis and Thermalanalyzer to check the thermal stability. Results showed that the product formed is acarbonate substituted hydroxyapatite and its thermal stability is less when comparedwith pure hydroxyapatite.
Journal of Sol-Gel Science and Technology, 2021
Biocompatibility and bacterial infections are the primary concerns associated with the current bo... more Biocompatibility and bacterial infections are the primary concerns associated with the current bone graft substitutes. The application of wollastonite-based scaffolds for bone tissue engineering becomes a novel subject of interest. In the present study, a single phasic wollastonite scaffold was synthesised using citric acid-based sol-gel combustion route. Its physicochemical characteristics, antibacterial properties as well as its biocompatibility and osteogenic induction effect on human bone marrow derived stromal cells (hBMSCs) are yet to be explored. The TGA/DTA, XRD and SEM/EDX confirmed the characteristics of wollastonite. The antibacterial test indicated wollastonite inhibition of 47.81% and 45.54% for gram-positive, Staphylococcus aureus and Staphylococcus epidermidis and 47.04% and 46.07% for gram-negative, Escherichia coli and Pseudomonas aeruginosa bacterial strains, respectively. The SEM micrographs demonstrated an excellent attachment of hBMSCs on wollastonite and comparable to commercial hydroxyapatite (cHA) scaffold. The alamar blue cell proliferation assay confirmed 1.7-and 1.8-fold significant increase in hBMSCs seeded on wollastonite and cHA scaffold, respectively, on day 14 as compared with day 1. The immunohistochemistry analysis on Type-I collagen (Col1) and Bone morphogenetic protein-2 (BMP2) expression on day 14 confirmed the osteogenic differentiation of hBMSCs seeded on wollastonite and comparable with cHA scaffold. In conclusion, wollastonite scaffold has a greater potential to substitute bone grafts in orthopaedic applications.
Materials Research Express, 2020
Sol-gel combustion method was employed for the synthesis of monticellite (CaMgSiO4) ceramic powde... more Sol-gel combustion method was employed for the synthesis of monticellite (CaMgSiO4) ceramic powders using various fuels. Citric acid, succinic acid, tartaric acid, sucrose, urea, glycine, and L-alanine were used as fuels. Influence of calcination temperature on the phase evolution was investigated. Prepared monticellite powders were characterized using powder-XRD, FT-IR, and DLS techniques. XRD pattern reveals that the L-alanine is a suitable fuel among all the fuels studied and confirms the formation of pure monticellite. FT-IR spectra confirm the presence of characteristic functional groups associated with monticellite. DLS measurements show the particle size of the monticellite powders. Finally, Apatite formation ability studies were carried out by immersing the monticellite and monticellite-polymer (chitosan/chitin) composites in the SBF solution. Pure monticellite shows higher bioactivity than the composites and its surface analysis (SEM and EDS) reveals the deposition of spherical hydroxyapatite particles.
Polymers, 2021
Gellan-chitosan (GC) incorporated with CS: 0% (GC-0 CS), 10% (GC-10 CS), 20% (GC-20 CS) or 40% (G... more Gellan-chitosan (GC) incorporated with CS: 0% (GC-0 CS), 10% (GC-10 CS), 20% (GC-20 CS) or 40% (GC-40 CS) w/w was prepared using freeze-drying method to investigate its physicochemical, biocompatible, and osteoinductive properties in human bone-marrow mesenchymal stromal cells (hBMSCs). The composition of different groups was reflected in physicochemical analyses performed using BET, FTIR, and XRD. The SEM micrographs revealed excellent hBMSCs attachment in GC-40 CS. The Alamar Blue assay indicated an increased proliferation and viability of seeded hBMSCs in all groups on day 21 as compared with day 0. The hBMSCs seeded in GC-40 CS indicated osteogenic differentiation based on an amplified alkaline-phosphatase release on day 7 and 14 as compared with day 0. These cells supported bone mineralization on GC-40 CS based on Alizarin-Red assay on day 21 as compared with day 7 and increased their osteogenic gene expression (RUNX2, ALP, BGLAP, BMP, and Osteonectin) on day 21. The GC-40 CS–s...
Materials Letters, 2021
Abstract The multidisciplinary attribute of biomaterials requires scientists to contrive and conc... more Abstract The multidisciplinary attribute of biomaterials requires scientists to contrive and concoct the material, engineers to design and fabricate the prosthesis, and physicians to swot the response of natural tissues on artificial biomaterials implanted in the body. In this present experiment, energy efficient sol–gel combustion method has been adopted for the preparation of merwinite using citric acid as a reducing agent. Nitric acid played dual role as catalyst and oxidizer during gelation and combustion respectively. The XRD analysis confirmed that single phasic merwinite phase formation was achieved at 1000 °C without any secondary phase impurities. The bioactivity investigation of merwinite showed the deposition of hydroxyapatite on day three itself over the surface of the immersed scaffold in the physiological medium.
Materials Science and Engineering: C, 2021
This work is aimed to develop a biocompatible, bactericidal and mechanically stable biomaterial t... more This work is aimed to develop a biocompatible, bactericidal and mechanically stable biomaterial to overcome the challenges associated with calcium phosphate bioceramics. The influence of chemical composition on synthesis temperature, bioactivity, antibacterial activity and mechanical stability of least explored calcium silicate bioceramics was studied. The current study also investigates the biomedical applications of rankinite (Ca3Si2O7) for the first time. Sol-gel combustion method was employed for their preparation using citric acid as a fuel. Differential thermal analysis indicated that the crystallization of larnite and rankinite occurred at 795 °C and 1000 °C respectively. The transformation of secondary phases into the desired product was confirmed by XRD and FT-IR. TEM micrographs showed the particle size of larnite in the range of 100-200 nm. The surface of the samples was entirely covered by the dominant apatite phase within one week of immersion. Moreover, the compressive strength of larnite and rankinite was found to be 143 MPa and 233 MPa even after 28 days of soaking in SBF. Both samples prevented the growth of clinical pathogens at a concentration of 2 mg/mL. Larnite and rankinite supported the adhesion, proliferation and osteogenic differentiation of hBMSCs. The variation in chemical composition was found to influence the properties of larnite and rankinite. The results observed in this work signify that these materials not only exhibit faster biomineralization ability, excellent cytocompatibility but also enhanced mechanical stability and antibacterial properties.
Materials Science and Engineering: C, 2021
The current investigation aims to replace the synthetic starting materials with biowaste to synth... more The current investigation aims to replace the synthetic starting materials with biowaste to synthesize and explore three different silicate bioceramics. Pure silica from rice husk was extracted by decomposition of rice husk in muffle furnace followed by alkali treatment and acid precipitation. Raw eggshell and extracted silica were utilized for the preparation of wollastonite, diopside and forsterite by the solid-state method. The TG-DSC analysis shows that the crystallization temperature of wollastonite, diopside and forsterite was found to be 883 °C, 870 °C and 980 °C, respectively. The phase purity of wollastonite was attained at 1100 °C whereas diopside and forsterite were composed of secondary phases even after calcination at 1250 °C and 1300 °C respectively. All three materials behaved differently when exposed to the physiological environment, as wollastonite exhibited remarkable apatite deposition within 3 days whereas a distinct apatite phase was noticed on the surface of diopside after 2 weeks and forsterite shows the formation of apatite phase after five weeks of immersion. The rapid dissolution of Mg2+ ion from forsterite lowered the leaching of silicate ions into the simulated body fluid leading to poor apatite deposition over its surface. Chemical composition was found to plays a key role in the biomineralization ability of these bioceramics. Hemolysis and Lactate Dehydrogenase (LDH) release assays were performed to evaluate the hemocompatibility of silicate ceramics cultured at different concentrations (62.5, 125, and 250 μg/mL) with red blood cells and mononuclear leucocytes (MLs) of mice. The hemolytic activity of all the tested bioceramics was insignificant (less than 1%). The interaction between diopside and mouse multipotent mesenchymal stromal cells (MMSCs) caused a negligible increase in the number of apoptosis-associated Annexin V-binding cells whereas forsterite and wollastonite induced an increase in the number of the apoptotic cells only at the concentration of 250 μg/mL. The LDH assay did not show statistically significant changes in the proliferation of MMSCs after treatment with the bioceramics at the tested concentrations when compared to control (p > 0.05). This finding showed that the death of a part of cells during the first 24 h of incubation did not prevent the proliferation of MMSCs incubated with diopside, forsterite and wollastonite for 72 h.
Journal of Asian Ceramic Societies, 2020
The objective of the current study was to design a bioactive and mechanically stable ceramic/ pol... more The objective of the current study was to design a bioactive and mechanically stable ceramic/ polymer cement for repairing bone defects. Solvent casting method was utilized to prepare porous diopside/PMMA scaffolds. The characteristic functional groups associated with diopside and PMMA in the composites were confirmed by FT-IR spectroscopy. Scanning electron microscopy revealed that the surface of composites covered by small non-uniform pores having dimensions below 4 μm. It was found that the porosity of the composites can be altered by varying the content of filler (diopside) in the composites. The biomineralization ability and mechanical strength of PMMA were enhanced by fabricating it as a composite with diopside. The presence of apatite peaks on the surface of diopside/PMMA composites was observed after 4 weeks of immersion in SBF solution. The mechanical strength of diopside/ PMMA composites was found to match with cancellous bone. Hence, the compositional ratio and constituents played a key role in determining the activity of the composites. Bioactive silicates can be used as a filler in biomedical polymers for imparting ductility to ceramics for achieving advanced functionalities.
International Journal of Drug Delivery Technology, Apr 20, 2018
Hydroxyapatite is the inorganic constituent present in the bone and it is used as a drug delivery... more Hydroxyapatite is the inorganic constituent present in the bone and it is used as a drug delivery carrier in hard tissue regeneration applications. Hydroxyapatite was prepared by simple precipitation technique and the effect of experimental parameters on the phase formation was studied. Calcium nitrate tetra hydrate and diammonium hydrogen phosphate were taken as the calcium and phosphate source. The calcined powders were characterized by Fourier-Transform Infrared spectroscopy to identify the functional groups present in the product and also analyzed by powder X-ray diffraction to identify the phases present in the product. Results showed that the product formed is pure hydroxyapatite and it confirms that aging time and pH of the system plays a significant role in the phase formation.
Bioactive Materials, 2018
In the current work, forsterite samples with different surface area were investigated for its ant... more In the current work, forsterite samples with different surface area were investigated for its antibacterial activity. Dissolution studies show that the lower degradation of forsterite compared to other silicate bioceramics, which is a desirable property for repairing bone defects. Forsterite scaffold shows superior compressive strength than the cortical bone after immersion in simulated body fluid. Bactericidal tests indicate that the forsterite had inhibition effect on the growth of clinical bacterial isolates. Forsterite may be a suitable candidate material for load bearing applications with enhanced mechanical properties and lower degradation rate.
Advanced Powder Technology, 2019
This work reports on the preparation and characterization of mesoporous nano diopside (CaMgSi2O6)... more This work reports on the preparation and characterization of mesoporous nano diopside (CaMgSi2O6) 37 using a simple and cost-effective sol-gel combustion route. Stoichiometric oxidant/fuel ratio was adopted 38 for the combustion reaction. Eggshell was used as a calcium source, glycine (fuel) as reductant, magne-39 sium nitrate and nitric acid as oxidant were used in the preparation. The thermal behavior of the precur-40 sor was studied by thermo-gravimetric analysis (TGA) and heating microscopy. The temperature required 41 for the transformation of the precursor into pure diopside was optimized at 1100°C. Rietveld refinement 42 method was utilized to confirm the phase purity of diopside. The resultant powder contains 36 nm par-43 ticle with a specific surface area of 51 m2/g. The appearance of Ca, Mg, Si, and O peaks in EDX pattern 44 confirmed the existence of essential elements. The rapid consumption of calcium and phosphorus ions 45 from the simulated body fluid during dissolution indicated their involvement in apatite deposition on 46 the surface of the nano diopside. FT-IR spectra showed that the SiAO and SiAOASi groups were replaced 47 by phosphate bands due to hydroxyapatite deposition. The mechanical stability of the diopside after 48 bioactivity studies was found to be superior to the cancellous bone. The release of alkaline earth ions 49 (Ca2+ and Mg2+) from the diopside sample into the bacterial culture medium increases the pH (7.4), 50 which inhibits the bacterial growth. The surface properties, concentration, and type of bacteria are the 51 other factors responsible for the antibacterial activity of the nano diopside. 52
Micro & Nano Letters, 2018
International Journal of Drug Delivery Technology, 2016
Presently, various approaches have been exploited in the prolongation of gastric residence time w... more Presently, various approaches have been exploited in the prolongation of gastric residence time which includes floating drug delivery system (FDDS), swelling and expanding systems, bio-adhesive systems, modified shape systems and high density systems. Among various methods, floating drug delivery system is considered to be a predominant method. Gastric emptying of dosage forms is an extremely varying process and ability to extend and control the emptying time is a valuable resource for the dosage forms. This FDDS is having the ability to provides a solution for this purpose. The FDDS is a bulk density system lower than the gastric fluid, so that the rest will float on the stomach contents for a prolonged period of time and allowing the drug to release slowly at a desired rate from the system and intensifies the bio-availability of the drug having narrow absorption window. The main intension of writing this review on floating drug delivery system is to study the mechanism of flotatio...
Materials Science and Engineering: C, 2017
This study presents different fuels (Glycine and Urea) that can be used to synthesize nanocrystal... more This study presents different fuels (Glycine and Urea) that can be used to synthesize nanocrystalline forsterite by the sol-gel combustion method. The decomposition and ignition temperature of fuels was studied by thermo-gravimetric and differential scanning calorimetric analysis (TG-DSC). Pure forsterite was characterized by heating microscopy, Fourier transform infrared spectroscopy, X-ray Diffraction, Brunauer-Emmett-Teller, Scanning Electron Microscopy, and Energy dispersive X-ray spectroscopy. The HAP (hydroxyapatite) deposition ability, degradation and dissolution behaviour of forsterite was examined in simulated body fluid (SBF). The combusted forsterite precursor showed distinct thermal behaviour for each fuel when analyzed by heating microscopy. BET analysis showed that the particle size of forsterite synthesized using glycine was 28 nm, specific surface area 65.11 m 2 /g and average pore diameter 16.4 nm while using urea 1.951 μm, 0.939 m 2 /g, and 30.5 nm are the respective parameters. The dissolution of forsterite pointed to the consumption of Ca and P ions from SBF, the negligible release of Si ion into the SBF and these ionic interaction with SBF can be altered as per the material properties. The forsterite showed good antibacterial activity against S. aureus but lower activity against E. coli. The bactericidal activity of forsterite indicated that it can be used to inhibit biofilm formation in dental, bone implants and bacterial infection during surgical operations.
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Research Articles by Dr. Sasikumar Swamiappan