Uma Tirichurapalli Sivagnanam

Electrospinning of poly (3-hydroxybutyric acid) and gelatin blended thin films: fabrication, characterization, and application in skin regeneration

A tissue engineering scaffold should mimic the structure and biological function of native extracellular matrix proteins. Electrospinning is a simple and versatile method to produce ultrathin fibers for tissue engineering. Blended submicron fibers of poly (3-hydroxybutyric acid) and gelatin were electrospun using 1,1,1,3,3,3 hexafluoro-2-propanol as solvent. Cross linking of fibers was achieved using glutaraldehyde, and the resultant fibers were tested and analyzed using scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and Fourier transformed infrared spectroscopy (FTIR).The fibers were found to exhibit good tensile strength. Degradation studies were performed and analyzed using SEM and FTIR and proved the stability of fibers for tissue engineering applications. The fibrous scaffold supported the growth and rapid proliferation of human dermal fibroblasts and keratinocytes with normal morphology, thus proving its reliability in using it as a potential scaffold for skin regeneration.

Development and characterization of coaxially electrospun gelatin coated poly (3-hydroxybutyric acid) thin films as potential scaffolds for skin regeneration

The morphology of fibers synthesized through electrospinning has been found to mimic extracellular matrix. Coaxially electrospun fibers of gelatin (sheath) coated poly (3-hydroxybutyric acid) (PHB) (core) was developed using 2,2,2 trifluoroethanol(TFE) and 1,1,1,3,3,3 hexafluoro-2-propanol(HFIP) as solvents respectively. The coaxial structure and coating of gelatin with PHB fibers was confirmed through transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Thermal stability of the coaxially electrospun fibers was analyzed using thermogravimetric analysis(TGA), differential scanning calorimetry(DSC) and differential thermogravimetric analysis(DTA). Complete evaporation of solvent and gelatin grafting over PHB fibers was confirmed through attenuated total reflection-Fourier transformed infrared spectroscopy (ATR-FTIR). The coaxially electrospun fibers exhibited competent tensile properties for skin regeneration with high surface area and porosity. In vitro degradation studies proved the stability of fibers and its potential applications in tissue engineering. The fibers supported the growth of human dermal fibroblasts and keratinocytes with normal morphology indicating its potential as a scaffold for skin regeneration.

Poly (vinyl alcohol) Microspheres Sandwiched Poly (3-hydroxybutyric acid) Electrospun Fibrous Scaffold for Tissue Engineering and Drug Delivery

Three drug delivery systems viz. doxycycline hyclate entrapped poly (vinyl alcohol) (PVA) microspheres (DM), composite fibers of doxycycline hyclatepoly (3-hydroxybutyric acid) (PHB) electrospun fibers (DF), and doxycycline hyclateloaded poly (vinyl alcohol) (PVA) microspheres sandwiched between composite fibers consisting of poly (3-hydroxybutyric acid) (PHB) and doxycycline hyclate (DMF), were developed. The initial burst release studies revealed that DMF drug delivery system developed through suspension electrospinning possessed an optimal initial burst release for wound healing. The developed scaffolds will potentially function in mimicking the extracellular matrix and consecutively enhance healing through its optimal drug release thereby proving its mettle as potential wound dressings for skin regeneration.

Green synthesis of folic acid-conjugated gold nanoparticles with pectin as reducing/stabilizing agent for cancer theranostics

In the present study pectin, a natural polysaccharide was employed for the one pot aqueous synthesis of gold nanoparticles (GNPs). Pectin acted at the same time as both a reducing and stabilizing agent. The formation of pectin reduced GNPs (Pec-GNPs) was confirmed by using a UV-visible spectrophotometer, with a characteristic surface plasmon resonance (SPR) band at 527 nm. EDS analysis proved the presence of gold in the sample. The spherical morphology and crystalline nature of the Pec-GNPs was demonstrated by TEM analysis. The FTIR spectrum revealed the capping of pectin on the surface of the synthesised GNPs. Furthermore, the Pec-GNPs are found to be stable at different pH and electrolytic conditions. In vivo safety of the Pec-GNPs was established through zebra fish toxicity studies. The cationic drug doxorubicin was successfully loaded onto the synthesized anionic Pec-GNPs by an ionic complexation interaction. In vitro release studies confirmed the pH dependent sustained release of the doxorubicin. Doxorubicin loaded Pec-GNPs exhibited enhanced in vitro cytotoxicity on breast cancer cells compared to free doxorubicin, demonstrating that Pec-GNPs are efficient vehicles for the delivery of doxorubicin. Furthermore, chitosan coupled with folic acid (FA) was decorated with Pec-GNPs-DOX as a nanocarrier to improve the targeting and enhance the drug delivery to target cancer tissues by folic acid receptor-mediated endocytosis. It was concluded that the FA@Pec-GNPs-DOX were biocompatible and suitable for anti-cancer drug delivery, and were potentially promising as a new therapeutic system for cancer treatment.

In vivo efficiency of the collagen coated nanofibrous scaffold and their effect on growth factors and pro-inflammatory cytokines in wound healing

ABSTRACT Exploring the importance of nanofibrous scaffold with traditionally important medicine as a wound dressing material prevents infection and aids in faster healing of wounds. In the present study, the Collagen (COL) from the marine fish skin was extracted and employed for coating the Poly(3‐hydroxybutyric acid) (P)–Gelatin (G) nanofibrous scaffold with a bioactive Coccinia grandis extract (CPE) fabricated through electrospinning. Further, the fabricated collagen coated nanofibrous scaffold (PG‐CPE‐COL) applied to the experimental wound of rats and the wound healing was analyzed with by physiochemical and biological techniques. The increased level of hydroxyproline, hexosamine and uronic acid was observed in PG‐CPE‐COL treated than the other groups. The CPE and collagen in the nanofibrous scaffold accelerates the wound healing and thereby reduced the inflammation caused by the cyclooxygenase‐2 (COX‐2) and inducible nitric oxide synthases (iNOS) in wound healing. The nanofibrous scaffold has influenced the expression of various growth factors such as vascular endothelial growth factor (VEGF), epidermal growth factor (EGF) and transforming growth factor (TGF‐&bgr;). In addition, the PG‐CPE‐COL nanofibrous scaffold increases the deposition of collagen synthesis and accelerates reepithelialization. Thus, the results suggest that the collagen coated nanofibrous scaffold with bioactive traditional medicine enhanced the faster healing of wound. Graphical abstract Figure. No Caption available.

Facile synthesis and evaluation of quercetin reduced and dextran sulphate stabilized gold nanoparticles decorated with folic acid for active targeting against breast cancer

In the present work, gold nanoparticles (GNPs) were successfully prepared by green synthesis using a strong antioxidant Quercetin (Q) as a reducing agent in the presence of Dextran Sulphate (DS) as a stabilizing agent at room temperature (DS–Q–GNPs). DS–Q–GNPs were characterized by several in vitro techniques to understand their physiochemical and biological properties. However, the average particle size was found to be around 38 nm, and the zeta potential of DS–Q–GNPs was found to be around −42 mV, indicating that the particles were highly stable. TEM results showed that the particles prepared were nearly spherical and crystalline in nature. DS–Q–GNPs exhibited good stability and showed excellent biocompatibility in MTT assay using the NIH 3T3 fibroblast cell line. Similarly, hemocompatibility and in vivo zebra fish toxicity studies confirmed that the DS–Q–GNPs were highly biocompatible and safe in vivo. Doxorubicin (DOX) was successfully loaded on DS–Q–GNPs and decorated with folic acid (FA) for targeting drug delivery to the cancer site (DOX–DS–Q–GNPs–FA). In vitro drug release studies revealed the drug was released in a controlled manner. The anticancer activity of DOX–DS–Q–GNPs–FA against the human breast cancer cell lines (MCF-7) was evaluated using MTT assay. Both doxorubicin loaded GNPs and the free doxorubicin inhibit the growth of MCF-7 cells in a concentration-dependant manner. The enhanced activity of DOX–DS–Q–GNPs–FA against MCF-7 cells was observed with its effect on the cell cycle progression of MCF-7 cells using flow cytometry. Similarly, Western blotting was employed to understand the cell cycle pathways during the treatment of DOX–DS–Q–GNPs–FA. It was found that DOX-loaded DS–Q–GNPs conjugated with FA represent a new potential delivery system for improved cancer therapy.

Antiviral activity of Thiosemicarbazones derived from α-amino acids against Dengue virus†

The endemicity and seasonal outbreaks of Dengue disease in most tropical and subtropical countries underscores an urgent need to develop effective prevention and control measures. Development of a Dengue vaccine, which is complicated by the Antibody Dependent Enhancement effect (ADE), a viral inhibitor, seems prudent as it would inhibit the spread of the virus. In vitro methods such as MTT assay and plaque formation unit reduction assays were employed for screening the viral inhibitory property of α‐amino acid based Thiosemicarbazides. The results elicits that at concentrations not exceeding the maximum non cytotoxic concentration (MNCC), these compounds completely prevented Dengue virus infection in vero cells as indicated by the absence of cytopathic effects in a dose‐dependent manner. The high potency of Bz‐Trp‐TSC against all four types of Dengue virus infection elevates Thiosemicarbazide as a lead antiviral agent for Dengue disease. Screening small molecules for antiviral activity against the most rapidly spreading mosquito‐borne viral disease is being explored by several research groups. Our findings would help to augment the efforts to identify the lead compounds for antiviral therapy to combat the Dengue disease. J. Med. Virol. 89:546–552, 2017.

Fabrication of chitosan microparticles loaded in chitosan and poly(vinyl alcohol) scaffolds for tissue engineering application

In recent decades, the use of microparticle-mediated drug delivery is widely applied in the field of biomedical application. Here, we report the new dressing material with ciprofloxacin-loaded chitosan microparticle (CMP) impregnated in chitosan (CH) and poly(vinyl alcohol) (PVA) scaffold for effective delivery of drug in a sustained manner to the wound site. Moreover, the peculiar physiochemical and structural properties of the CH–CMP scaffold has proved better tensile strength and excellent swelling to achieve 82% of drug release. In vitro biocompatibility was done for both scaffold using NIH 3T3 fibroblasts and human keratinocytes (HaCaT) cell lines. In vitro fluorescent activity showed distinct biocompatibility with good cell adhesion and proliferation. However, the CH–CMP scaffold showed best result to act as promising biomaterial in effective drug delivery in tissue engineering.

Development of antiviral inhibitor against dengue 2 targeting Ns3 protein: In vitro and in silico significant studies

Dengue fever is a severe, widespread disease with more than 2 million diagnosed infections per year. The Dengue virus protease represents a cardinal target for prudent drug design. Among the four serotypes Dengue 2 is known for the occurrence of its frequent epidemics. The new compound inhibited the Dengue-2 in the low-micromolar range in cells. At the moment, protease inhibitors are not actively tried against dengue virus as therapeutic option. We have identified thiosemicarbazones derived phenyl-acetyl ketones as candidate for a novel class of protease inhibitors. Here, we report the selective and non-competitive inhibition of the Dengue virus serotype 2 in vitro and in silico. Molecular docking suggests binding at a specific active site. In addition to the docking assays, few techniques were developed to interpret these moleculess antiviral profile in vitro.

A novel assembly pheromone trap for tick control in dog kennels

A novel ecofriendly sticky tick trap device for the control of dog tick Rhipicephalus sanguineus using gold nanoparticle assembly pheromone complex as a bait was developed. Assembly pheromones comprising of guanine, xanthine and adenine in the ratio of 25:1:1 was encapsulated in gold nanoparticle. The response of the different stages of unfed R. sanguineus ticks was evaluated using petridish bioassay. Statistical analysis was done using chi-square test. Petridish bioassay with unfed stages of R. sanguineus revealed that 100% of the larvae, nymph and adults were attracted to assembly pheromone nanogold complex within 24h. Of the 952 ticks trapped, ticks of different stages trapped in total by the baited sticky trap device, 543 (57%) were engorged and 409 (43%) were unfed ticks. The study revealed that assembly pheromone baited traps has the potential to control tick infestations in dog kennels.