Papers by Debanjan Sarkar
Journal of Ergonomics, 2012
Macromolecular Materials and Engineering, 2016
Segmental polyurethanes (PU) with hydrophilic segments form colloidal dispersions which are ultim... more Segmental polyurethanes (PU) with hydrophilic segments form colloidal dispersions which are ultimately arrested into gel-like structure in aqueous continuous phase owing to the differential interactions between polymer and solvent. These structural states of amphiphilic PUs evolve hierarchically, but the structure-function correlation between PU colloidal dispersion and gels is not clear. Here, this correlation is defined from the mechanomorphology of hydrophilic polyethylene glycol based PU which forms dispersions and finally transforms into gel-structure. Morphological and rheological analyses show that PU with comparable hydrophilic and hydrophobic content forms attractive colloids with self-similar fractal microstructures whereas PU with increased hydrophilic character forms space-filling colloids without any defined organization. Furthermore, colloidal dispersions are densified under shear or gravity to form gel where gel mechanics is defined by colloidal particle organization and the morphology is dependent on gelation mode. This stepwise organization of PU colloidal particles into microgel can independently control microgel mechanics and morphology.
ACS Biomaterials Science & Engineering, 2016
Monthly Notices of the Royal Astronomical Society
The anisotropy of the redshift space bispectrum contains a wealth of cosmological information. Th... more The anisotropy of the redshift space bispectrum contains a wealth of cosmological information. This anisotropy depends on the orientation of three vectors $\boldsymbol {k_1},\boldsymbol {k_2},\boldsymbol {k_3}$ with respect to the line of sight. Here, we have decomposed the redshift space bispectrum in spherical harmonics which completely quantify this anisotropy. To illustrate this, we consider linear redshift space distortion of the bispectrum arising from primordial non-Gaussianity. In the plane-parallel approximation, only the first four even ℓ multipoles have non-zero values, and we present explicit analytical expressions for all the non-zero multipoles, that is, upto ℓ = 6 and m = 4. The ratio of the different multipole moments to the real-space bispectrum depends only on β1 the linear redshift distortion parameter and the shape of the triangle. Considering triangles of all possible shapes, we have studied how this ratio depends on the shape of the triangle for β1 = 1. We have...
ACS Applied Materials & Interfaces
Langmuir : the ACS journal of surfaces and colloids, Jun 20, 2017
Colloidal gels are three-dimensional networks of microgel particles and can be utilized to design... more Colloidal gels are three-dimensional networks of microgel particles and can be utilized to design microtissues where the differential adhesive interactions between the particles and cells, guided by their surface energetics, are engineered to spatially assemble the cellular and colloidal components into three-dimensional microtissues. In this work we utilized a colloidal interaction approach to design cell-polyurethane (PU) microgel bimodal microtissues using endothelial cells (ECs) as a normal cell model and a nonmalignant breast cancer cell line (MCF-7) as a cancer cell model. PU microgels were developed from a library of segmental polyurethanes with poly(ethylene glycol) soft segment and aliphatic diisocyanate/l-tyrosine based chain extender as hard segment to modulate the interactions between PU colloidal particles and cells. The surface energies of the microgel particles and cells were estimated using Zisman's critical surface tension and van Oss-Good-Chaudhury theory (vOGC...
Bulletin of the American Physical Society, Mar 4, 2014
Journal of the Indian Chemical Society, 2002
TECHNOLOGY, 2015
Polyurethanes (PUs) are composed of soft and hard segments, and segmental interactions induce bip... more Polyurethanes (PUs) are composed of soft and hard segments, and segmental interactions induce biphasic morphologies which can influence endothelial cell (EC) organization by regulating cell–matrix and cell–cell interactions. In this study, we explored this effect using poly(caprolactone) (PCL)-based PU, where the soft segment was composed of PCL and the hard segment was composed of hexamethylene diisocyanate (HDI) and L-tyrosine-based dipeptide (DTH). The composition of the PUs was varied by altering the PCL molecular weight and correspondingly, different phase morphologies were observed. Organization and functional state of ECs on these PUs showed that composition and phase morphology of PU have a significant effect on cellular response. The ECs formed an organized network with cord-like structures which resulted in interconnected loops when soft and hard segment fractions were phase-separated. VE-cadherin (for cell–cell adherence) and vinculin (for cell–matrix focal adhesion) loca...
Endothelial cells interact with nano-scale structures of extracellular matrices to form blood ves... more Endothelial cells interact with nano-scale structures of extracellular matrices to form blood vessels. Segmental polyurethanes present nano-structured phases in polyurethanes (PUs) which can influence cell fate [1]. We hypothesized that nanophase morphology of PU can influence endothelial cells to form structures which can assemble into blood vessel architectures. Therefore, phases of PU can provide a biochemical and biophysical matrix environment, and, thereby controlling cell–matrix interaction for artificial vessel regeneration. In this study, we illustrate that the nanostructured biodegradable PUs can control cell adhesion, morphology, and structure of human umbilical vein endothelial cells (HUVEC). Specifically, PUs were designed from L-tyrosine based dipeptide chain extender and aliphatic diisocyanate with polycaprolactone (PCL) and used to analyze the role of PU phases in regulating cell morphology and tubular network assembly.
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Papers by Debanjan Sarkar