Arumugam Gnanamani

pH and redox sensitive albumin hydrogel: A self-derived biomaterial

Serum albumin can be transformed to a stimuli (pH and redox) responsive hydrogel using the reduction process followed by oxidative refolding. The preparation of albumin hydrogel involves a range of concentrations (75, 150, 300, 450, 600 and 750u2009μM) and pH (2.0–10.0) values and the gelation begins at a concentration of 150u2009μM and 4.5–8.0 pH value. The hydrogel shows maximum swelling at alkali pH (pHu2009>u20099.0). The increase in albumin concentration increases hydrogel stability, rheological property, compressive strength, proteolytic resistance and rate of in vivo biodegradation. Based on the observed physical and biological properties of albumin hydrogel, 450u2009μM was determined to be an optimum concentration for further experiments. In addition, the hemo- and cytocompatibility analyses revealed the biocompatibility nature of albumin hydrogel. The experiments on in vitro drug (Tetracycline) delivery were carried out under non reducing and reducing conditions that resulted in the sustained and fast release of the drug, respectively. The methodology used in the preparation of albumin hydrogel may lead to the development of autogenic tissue constructs. In addition, the methodology can have various applications in tissue engineering and drug delivery.

In vitro and in vivo assessments of a 3-(3,4-dihydroxyphenyl)-2-propenoic acid bioconjugated gelatin-based injectable hydrogel for biomedical applications

Imparting functional properties on a biomaterial for high end applications is always a challenging task. In the present study, an attempt was made to construct an injectable hydrogel through bioconjugation of dihydroxy phenolic acids to a gelatin backbone. Bioconjugating caffeic acid with gelatin followed by oxidation with mild oxidation agents provided a hydrogel with all the requisite properties (biocompatibility, controlled biodegradability, and antioxidant, antimicrobial and wound healing ability). Bioconjugation was performed using EDC/NHS and the resultant gel named as caffeic acid bioconjugated gel (CBG gel). The physicochemical, rheological, swelling, in vitro (biocompatibility, biodegradability, antimicrobial properties, antioxidant properties and drug release properties) and in vivo (biocompatibility, biodegradability and wound healing properties) studies on the CBG gel were carried out using standard protocols. The bioconjugation was confirmed by 1H NMR and UV-Vis analysis. Rheological analysis of the CBG gel revealed that the storage modulus was greater than the loss modulus at all the frequencies and suggested the elastic nature of the gel. About 50% weight gain within 12 hours during swelling studies and 50% weight loss within 12 hours during evaporation suggested the suitability of the CBG gel as a drug carrier. The drug release studies implied that there was an initial burst and later the release was sustained. The CBG gel promotes cell migration and demonstrates radical scavenging behavior. When subcutaneously injected into the animal, as in situ CBG gel, the gel was highly biocompatible and did not cause any necrosis. The crosstalk with adjacent tissue cells was smooth and the gel completely degraded within 24 days. The wound healing efficacy on full-thickness wounds suggested that the CBG gel accelerated healing and imparted high strength on the healed skin at an appreciable level. With all these additional functional properties, the CBG gel could be useful for biomedical applications.

Identification and Discrimination of Methicillin Resistant Staphylococcus aureus Strains Isolated from Burn Wound Sites Using PCR and Authentication with MALDI-TOF–MS

The present study demonstrates isolation and identification of methicillin resistance Staphylococcus aureus (MRSA) strains in the samples collected from burn patients. About 106 swab samples were collected from burn patients of >40% burn injury and were subjected to isolation using nutrient agar followed by screening using Me Re Sa selective medium agar. A total of 10 isolates with identity to S. aureus were obtained and further authenticated using Polymerase Chain Reaction and matrix assisted laser desorption/ionization time of flight mass spectrometry analysis. Presence of mec A gene and the peak pattern observations suggested seven of the 10 isolates are MRSA. Thus, the present study emphasizes the process of identification of MRSA using two different bio-analytical techniques, which authenticate the presence of MRSA.

Biopolymer from microbial assisted in situ hydrolysis of triglycerides and dimerization of fatty acids.

The present study demonstrates biopolymer production by in situ bio-based dimerization of fatty acids by microorganism isolated from marine sediments. Microbial isolate grown in Zobell medium in the presence of triglycerides for the period of 24-240 h at 37 degrees C, hydrolyze the applied triglycerides and sequentially dimerized the hydrolyzed products and subsequently polymerized and transformed to a biopolymer having appreciable adhesive properties. Physical (nature, odour, stickyness and tensile strength), chemical (instrumentation) and biochemical (cell free broth) methods of analyses carried out provided the hypotheses involved in the formation of the product as well as the nature of the product formed. Results revealed, lipolytic enzymes released during initial period of growth and the biosurfactant production during later period, respectively, hydrolyze the applied triglycerides and initiate the dimerization and further accelerated when the incubation period extended. The existence and the non-existence of in situ hydrolysis of various triglycerides followed by dimerization and polymerization and the mechanism of transformation of triglycerides to biopolymer are discussed in detail.

Phylogenetic Framework and Biosurfactant Gene Expression Analysis of Marine Bacillus spp. of Eastern Coastal Plain of Tamil Nadu

The present study emphasizes the diversity assessment of marine Bacillus species with special reference to biosurfactant production, respective gene expression, and discrimination among Bacillus licheniformis and Bacillus subtilis. Among the 200 individual species of eastern coastal plain of Tamil Nadu screened, five biosurfactant producing potential bacterial species with entirely different morphology were selected. Biochemical and 16S rRNA gene sequence analysis suggested that all the said five species belong to Bacillus genera but differ in species levels. Biosurfactant of all the five species fluctuates in greater levels with respect to activity as well as to constituents but showed partial similarity to the commercially available surfactin. The expression of srf gene was realized in all of the five species. However, the sfp gene expression was observed only in three species. In conclusion, both B. licheniformis and B. subtilis demonstrate srf gene; nevertheless, sfp gene was expressed only by Bacillus subtilis.

Redox responsive albumin autogenic nanoparticles for the delivery of cancer drugs

The present study explores preparation and characterization of redox sensitive albumin autogenic nanoparticles (ANPs) for drug delivery applications. Human serum albumin nanoparticles are prepared by desolvation method. The particles are stabilized through self-crosslinking and no external stabilizers are involved in the preparation. ANPs are then subjected to Camptothecin (CPT) drug loading. Experiments on in vitro and in vivo release profile, cytotoxic and cytocompatability, hemocompatability, blood clearance, tracking and bio imaging are studied in detail. The redox sensitive and drug release properties of ANPs studied in the presence of glutathione. Results on the physical, chemical and instrumental characterization warrant the property of the nanoparticles. ANPs obtained in the present study is biocompatible, biodegradable, effectively entangle the chosen drug, release the drug in the controlled manner, sensitive to reducing environment, nil toxicity and appreciable uptake by cells. In the current scenario on the requirement of a drug carrier with redox sensitive property to encounter cancer cells, the results of the present study on albumin nanoparticles with redox sensitivity is smart and pave the way in the cancer therapeutics.

Transformation of Soybean Oil to Various Self-Assembled Supramolecular Structures

Today’s research worlds try to bring everything in nanosize and the tremendous development on nanosize and technology introduced numbers of molecules with immense applications. Though nanostructures from numbers of metals and materials are being synthesized, supramolecular structures attracts the research group at increasing level, because of the interest and urge to know the origin of life. Hence, research groups at global level are making attempts on how the self-assembly and the supramolecular structures have been formed from the single and /or from the combination molecules. Thus the design and the construction of supramolecular assembly/structures are quite interesting and various hypothetical theories have been developed to substantiate the origin of life. Supramolecular structures are large molecules fashioned by binding of smaller molecules mutually and it often to develop molecules of preferred form including 2D triangles, squares, pentagons, hexagons and 3D octahedrons, cubes and some irregular shapes. Self-assembly is the most prevailing methodology in the design of large, distinct, ordered structures. The objects of supramolecular chemistry are defined on one hand by the nature of the molecular components and on the other by the type of interactions that hold them together. Three major steps are involved in supramolecular systems; (i) selective binding, (ii) growth of the components in the correct relative orientation and (iii) termination requiring a built in feature which signifies the end process. The chemistry of supramolecular structure is a constitutional dynamic chemistry due to the reversibility of the connecting events. The kinetic liability confers the self-assembling systems to undergo annealing and self-healing of defects and to manifest tunable degree of polymerization and cohesive properties. In contrast, covalent linked, nonlabile type cannot heal spontaneously and the defects are permanent (Lehn, 2005). According to Murakami, synthesis of supramolecular structure is based on the principle of molecular recognition and molecular self-assembly realized due to the formation of noncovalent interaction towards the cooperation of many weak bonds including electrostatic interaction, Van der Waals forces, dipole interaction, hydrogen bonding, hydrophobic interaction, and π–π interaction. Recently the interest was drawn to a new topological form of supramolecular structures by self-assembly and also by weak interactions.