Synthesis of self-assembly of agarose-fatty acid ester nanoparticles

679-687Microwave assisted facile synthesis of hydrophobically modified nano-sized particulate esters of agarose and stearic and palmitic acids (Ag-SA and Ag-PA), employing carbodiimide chemistry has been described. The hydrophobically modified agarose is capable of forming self-assembled nano-sized particles. Physicochemical characterization of Ag-SA, Ag-PA has been carried out by gel permeation chromatography, differential scanning calorimetric, scanning electron microscopy and FT-IR, 13C-NMR and 1H-NMR spectra. The aqueous self-assembly of the modified polymer has been studied by dynamic light scattering and transmission electron microscopy, which shows the formation of 4-5 nm micelles, and 220-250 nm polymeric vesicles. TEM images demonstrate that the self-aggregate is spherical in shape. These new agarose based nano-sized materials may be of potential utility in biomedical applications as drug delivery vehicles

Antioxidant activity and phytochemical analysis of a few Indian seaweed species

507-518Antioxidant activities of crude methanol extracts and fractions of the seaweed species viz. Bryopsis plumosa (BP), Dictyopteris australis (DA) and Gracilaria pudumadamensis (GP) of Indian waters were evaluated and correlated with their phytochemical contents. In DPPH assays the most promising antioxidant sample was the crude methanol extract (BPM), which was comparable with standard antioxidant BHT. In the superoxide radical activity assays no sample in the group was as active as BHT, however the promising ones were DAM, DAE and GPM, GPE, GPH (subscripts M, E and H stand for the respective methanol extracts and their ethyl acetate and hexane fractions). In the Fe2+ chelating activity assays EDTA showed far stronger activity than those of the promising samples. In reducing power assays BPM, BPE, and BPH showed comparable activity with BHT at a concentration 0.5 mg/mL. Thus these seaweed species would be of potential utility as a source of natural antioxidants

Customized Peptide Biomaterial Synthesis via an Environment-Reliant Auto-Programmer Stigmergic Approach

Stigmergy, a form of self-organization, was employed here to engineer a self-organizing peptide capable of forming a nano- or micro-structure and that can potentially be used in various drug delivery and biomedical applications. These self-assembling peptides exhibit several desirable qualities for drug delivery, tissue engineering, cosmetics, antibiotics, food science, and biomedical surface engineering. In this study, peptide biomaterial synthesis was carried out using an environment-reliant auto-programmer stigmergic approach. A model protein, α-gliadin (31, 36, and 38 kD), was forced to attain a primary structure with free –SH groups and broken down enzymatically into smaller fragments using chymotrypsin. This breakdown was carried out at different environment conditions (37 and 50 °C), and the fragments were allowed to self-organize at these temperatures. The new peptides so formed diverged according to the environmental conditions. Interestingly, two peptides (with molecular weights of 13.8 and 11.8 kD) were isolated when the reaction temperature was maintained at 50 °C, while four peptides with molecular weights of 54, 51, 13.8, and 12.8 kD were obtained when the reaction was conducted at 37 °C. Thus, at a higher temperature (50 °C), the peptides formed, compared to the original protein, had lower molecular weights, whereas, at a lower temperature (37 °C), two peptides had higher molecular weights and two had lower molecular weights

Synthesis and Evaluation of a Sodium Alginate-4-Aminosalicylic Acid Based Microporous Hydrogel for Potential Viscosupplementation for Joint Injuries and Arthritis-Induced Conditions

A microporous hydrogel was developed using sodium alginate (alg) and 4-aminosalicylic acid (4-ASA). The synthesized hydrogel was characterized using various analytical techniques such as Fourier transform infrared spectroscopy (FTIR), Carbon-13 nuclear magnetic resonance (13C-NMR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Additonal carboxyl and hydroxyl functional groups of 4-ASA provided significant lubrication and stress-triggered sol-gel transition to the conjugated hydrogel. In addition, cytotoxicity analysis was undertaken on the conjugated hydrogel using human dermal fibroblast-adult (HDFa) cells, displaying non-toxic characteristics. Drug release profiles displaying 49.6% in the first 8 h and 97.5% within 72 h, similar to the native polymer (42.8% in first 8 h and 90.1% within 72 h). Under applied external stimuli, the modified hydrogel displayed significant gelling properties and structure deformation/recovery behaviour, confirmed using rheological evaluation (viscosity and thixotropic area of 8095.3 mPas and 26.23%, respectively). The modified hydrogel, thus, offers great possibility for designing smart synovial fluids as a biomimetic aqueous lubricant for joint-related injuries and arthritis-induced conditions. In addtion, the combination of thixotropy, non-toxicity, and drug release capabilities enables potential viscosupplementation for clinical application