Shantikumar V Nair

Amrita Institute of Medical Sciences and Research Centre, Fort Cochin, Kerala, India

Are you Shantikumar V Nair?

Claim your profile

Publications (263)916.32 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A peculiar architecture of one-dimensional MnO2 nanowires was synthesized by an optimized hydrothermal route and has been lucratively exploited to fabricate highly efficient microporous electrode overlays for lithium batteries. These fabricated electrodes comprised of interconnected nanoscale units with wire-shaped profile which exhibits high aspect ratio in the order of 102. Their outstanding intercalation/de-intercalation prerogatives have also been studied to fabricate lithium coin cells which revealed a significant specific capacity and power density of 251 mAh g−1 and 200 W kg−1, respectively. A detailed electrochemical study was performed to elucidate how surface morphology and redox reaction behaviors underlying these electrodes influence the cyclic behavior of the electrode. Rate capability tests at different C-rates were performed to evaluate the capacity and cycling performance of these coin cells.
    Materials Research Bulletin 10/2015; 70. DOI:10.1016/j.materresbull.2015.04.012 · 2.29 Impact Factor
  • Source
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study provides detailed experimental results on the synthesis and characterization of carbonized lithium titanate spinel (LTO) composites as electrode materials for lithium ion capacitor. The LTO particles were grafted with a porous carbon layer obtained from the pyrolysis of camphor. The graphitic nature of the carbon was confirmed through Raman spectroscopy. The relative contributions from the capacitive and diffusion controlled processes underlying these electrodes were mathematically modeled. Electron transport mechanism underlying these electrodes was determined by measuring the work functions (φ) of LTO and carbon grafted LTO using ultraviolet photoelectron spectroscopy. These carbon grafted LTO composites exhibited an energy density of 330 mWh·L−1 and a peak power density of 2.8 kW·L−1, when employed as electrodes in coin cells with excellent cycling stability at the end of 4000 cycles.
    05/2015; 24(3). DOI:10.1016/S2095-4956(15)60320-5
  • [Show abstract] [Hide abstract]
    ABSTRACT: The dental follicle is a source of dental follicle stem cells (DFCs), which have the potential to differentiate into the periodontal lineage. DFCs therefore are of value in dental tissue engineering. The purpose of this study was to evaluate the effect of growth factor type and concentration on DFC differentiation into periodontal specific lineages. DFCs were isolated from the human dental follicle and characterized for the expression of mesenchymal markers. The DFCs were positive for CD-73, CD-44 and CD-90; and negative for CD-33, CD-34 and CD-45. The expression of CD-29 and CD-31 was almost negligible. The cells also expressed periodontal ligament and cementum markers such as periodontal ligament associated protein-1 (PLAP-1), fibroblast growth factor-2 (FGF-2) and cementum protein-1 (CEMP-1), however, the expression of osteoblast markers was absent. Further, the DFCs were cultured in three different induction medium to analyze the osteoblastic, fibroblastic and cementoblastic differentiation. RUNX-2, ALP activity, alizarin staining, calcium quantification, collagen Type-1 (Col-1) and osteopontin (OPN) expression confirmed the osteoblastic differentiation of DFCs. DFCs cultured in recombinant human fibroblast growth factor-2 (rhFGF-2) containing medium showed enhanced PLAP-1, FGF-2 and COL-1 expression with increasing concentration of rhFGF-2 confirmed periodontal ligament fibroblastic differentiation. Similarly, DFCs cultured in recombinant human cementum protein-1 (rhCEMP-1) containing medium showed enhanced BSP-2, CEMP-1 and COL-1 expression with respect to rhCEMP-1 confirmed cementoblastic differentiation. The expression of osteoblast, fibroblast and cementoblast related genes of DFCs cultured in induction medium was enhanced in comparison to DFCs cultured in non-induction medium. Thus growth factor dependent differentiation of DFCs into periodontal specific lineages was proved by quantitative analysis.
    Tissue Engineering Part C Methods 05/2015; DOI:10.1089/ten.TEC.2014.0603 · 4.64 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The desire and need to minimize traditional open surgeries is gearing up as it could reduce the healthcare expenses and improve the recovery time for the patients. Minimal invasive procedures using endoscopes, catheters and needles have been developed considerably in the last few decades. In the field of tissue engineering and regenerative medicine, there is a need for advancement over the conventional scaffolds and pre-formed hydrogels. In this scenario, injectable hydrogels have gained wider appreciation among the researchers, as they can be used in minimally invasive surgical procedures. Injectable gels with their ease of handling, complete filling of the defect area and good permeability have emerged as promising biomaterials. The system can effectively deliver a wide array of therapeutic agents like drugs, growth factors, fillers and even cells. This review provides an overview of the recent trends in the preparation of injectable hydrogels, along with key factors to be kept in balance for designing an effective injectable hydrogel system. Further, we have summarized the application of injectable hydrogels in adipose, bone, cartilage, intervertebral discs and muscle tissue engineering.
    European Polymer Journal 05/2015; DOI:10.1016/j.eurpolymj.2015.05.014 · 3.24 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Injectable gel systems, for the purpose of bone defect reconstruction has more advantages like controlled flowability, adaptability to the defect site, increased handling properties when compared to the conventionally used autologous graft, scaffolds, hydroxyapatite blocks etc. In this work, nano hydroxyapatite (nHAp) incorporated chitin-poly (ε-caprolactone) (PCL) based injectable composite microgels has been developed by simple regeneration technique for cranial defect repair. The prepared microgels systems were characterized using scanning electron microscope (SEM), Fourier transformed infra-red spectroscopy (FTIR) and X-ray diffraction (XRD). The composite microgel with the incorporation of nHAp, showed an increased elastic modulus, thermal stability and had shear-thinning behavior proving the injectability of the system. The protein adsorption, cytocompatibility and migration of rabbit adipose derived mesenchymal stem cells (rASCs) were also studied. Chitin-PCL-nHAp microgel elicited an early osteogenic differentiation compared to control gel. The immunofluorescence studies confirmed the elevated expression of osteogenic-specific markers such as alkaline phosphatase, osteopontin and osteocalcin in chitin-PCL-nHAp microgels. Thus chitin-PCL-nHAp microgel could be a promising injectable system for regeneration of bone defects which are even in deeper planes, irregularly shaped and complex in nature.
    ACS Applied Materials & Interfaces 04/2015; 7(18). DOI:10.1021/acsami.5b02685 · 5.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We synthesized a uniquely shaped one-dimensional (1-D) TiO2 nanostructure having the morphology of yellow bristle grass with high surface area by titanate route under soft reaction conditions. The electrospun TiO2-SiO2 composite nanofibers upon treatment with concentrated NaOH at 80 0C under ambient pressure for 24 h resulted in sodium titanate (Na2Ti3O7) nanostructures. The Na2Ti3O7 nanostructures have an overall 1-D fibrous morphology but the highly porous fiber surfaces were decorated with layered thorn-like features (a morphology resembling that of yellow bristle grass) resulting in high surface area (113 m2/g) and porosity. The Na2Ti3O7 nanostructures were converted into TiO2 nanostructures of the same morphology by acidification (0.1 N HCl) followed by low temperature sintering (110 0C) processes. Dye-sensitized solar cells (DSCs) constructed out of the material (cells of area 0.20 cm2 and thickness of 12 m) showed a power conversion efficiency (η) of 8.02 % in comparison to commercial P-25 TiO2 (η = 6.1 %).
    Dalton Transactions 04/2015; 44(20). DOI:10.1039/C5DT01027F · 4.10 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cancer kinome is now well organized as an important target for a new class of cancer drugs. There are more than 500 members in the kinase family in which some of them are clinically analysed .while the rest are under investigation for potential therapeutic applications. Phosphorylation, major function of kinases is one of the most significant signal transduction mechanism in which intercellular signals regulate intracellular processes like ion transport, hormone responses and cellular proliferation. Any deregulation of kinase function may lead to tumor progression and other disorders such as immunological, neurological , metabolic and including also for the case of infectious diseases. This led to the necessity in the development of kinase inhibitors as therapeutic agent. Herein we discuss about different types of kinases and their inhibitors in various types of cancers. This review portrays a broad overview on the origin of kinases, discovery, characterization and mode of action of kinase inhibitors in cancer therapy.
    Current drug targets 04/2015; · 3.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, graphene oxide (GO) nanoflakes (0.5 and 1 wt%) were incorporated into a gelatin-hydroxyapatite (GHA) matrix through a freeze drying technique and its effect to enhance mechanical strength and osteogenic differentiation was studied. The GHA matrix with GO demonstrated less brittleness in comparison to GHA scaffolds. There was no significant difference in mechanical strength between GOGHA0.5 and GOGHA1.0 scaffolds. When the scaffolds were immersed in phosphate buffered saline (to mimic physiologic condition) for 60 days, around 50-60% of GO was released in sustained and linear manner and the concentration was within the toxicity limit as reported earlier. Further, GOGHA0.5 scaffolds were continued for cell culture experiments, wherein the scaffold induced osteogenic differentiation of human adipose derived mesenchymal stem cells without providing supplements like dexamethasone, L-ascorbic acid and β glycerophosphate in the medium. The level of osteogenic differentiation of stem cells was comparable to those cultured on GHA scaffolds with osteogenic supplements. Thus biocompatible, biodegradable and porous GO reinforced gelatin-HA 3D scaffolds may serve as a suitable candidate in promoting bone regeneration in orthopaedics.
    Nanotechnology 03/2015; 26(16):161001. DOI:10.1088/0957-4484/26/16/161001 · 3.67 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Stable nano-formulation of Plumbagin nanoparticles from Plumbago zeylanica root extract was explored as a potential natural drug against prostate cancer. Size and morphology analysis by DLS, SEM and AFM revealed the average size of nanoparticles prepared was 100±50nm. In vitro cytotoxicity showed concentration and time dependent toxicity on prostate cancer cells. However, plumbagin crude extract found to be highly toxic to normal cells when compared to plumbagin nanoformulation, thus confirming nano plumbagin shows cytocompatibility with normal cells and dose dependent toxicity to prostate cells. In vitro haemolysis assay confirmed the blood biocompatibility of the plumbagin nanoparticles. In wound healing assay, plumbagin nanoparticles provided clues which might play an important role in the anti-migration of prostate cancer cells. DNA fragmentation revealed that partial apoptosis induction by plumbagin nanoparticles could be expected as a potent anti-cancer agent against prostate cancer.
    Current Drug Delivery 03/2015; · 2.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Prostate cancer has been diagnosed as the second most frequent and the sixth among the cancer causing deaths among men worldwide. There is a limited scope for the prevalent therapies as prostate cancer advances and they present adverse aftermaths that have put way for us to delve into naturally available anticancer agents. The main objective of the present work is to compile the advantages of ayurvedic herbal formulations with modern technology. Baliospermum montanum is a plant that is used in ayurveda for the treatment of cancer and the plant is studied to possess various constituents in it that are responsible for its anticancer activity. Stable nanoparticles of B. montanum were prepared from both the aqueous and ethanolic extracts of the plant and its cytotoxic effects were studied on prostate cancer and normal cell lines. Size analysis by DLS and SEM revealed the average size of nanoparticles prepared was 100±50nm and 150±50nm for the nanoparticles prepared from aqueous and ethanolic extract respectively. In vitro cytotoxicity showed a concentration and time dependent toxicity on prostate cancer cells with cell viability of 22% and 6% with maximum concentration of aqueous and ethanolic nanoparticles respectively, in 48h. In vitro hemolysis assay confirmed that the prepared nanoparticles were compatible with blood with no occurrence of hemolysis. The nanoparticles showed a significant reduction in the colony forming ability and wound healing capacity of the prostate cancer cells. These studies hold the anti cancer potential of the B. montanum nanoparticles making it an important candidate for prostate cancer therapy. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
    Biomedecine [?] Pharmacotherapy 02/2015; 71. DOI:10.1016/j.biopha.2015.02.016 · 2.11 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pectin is a natural polysaccharide and the pectin scaffold system has proved to be suitable for an intended use towards biomedical applications, such as drug delivery and tissue engineering. Studies on gemcitabine loaded pectin-fibrin scaffold have shown it to be cytotoxic towards ovarian cancer cells at the in vitro level. Our present study aims at substantiating the biocompatibility of the pectin-fibrin composite scaffold in a mouse implantation model in order to prove the compatibility of the scaffold system in vivo. Composite scaffolds were implanted and the biocompatibility was assessed after the 1st, 6th and 12th week of study, respectively. Macroscopic inspection of the implantation site revealed no pathological inflammatory responses and histopathology studies depicted remarkable neutrophil accumulation within the implant in a timely manner. Furthermore, the immune response indicated significant difference with cytokines IL-1 beta, IL-10, and IL-17 alpha, respectively. These results suggested that this scaffold system could be a promising targeted drug delivery system for the slow release of drugs in a mouse disease model.
    Cellulose Chemistry and Technology 02/2015; 49(1):55-60. · 0.83 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study demonstrates a low temperature hydrothermal route for the synthesis of α-cobalt hydroxide comprising of randomly arrayed nano strands in a three dimensional plane. These micro/nano hybrid structures were used as building blocks for processing high surface area supercapacitor electrodes. Surface area of these structures was measured to be ∼100 m2g−1. The influence of surface morphology in three different electrolytes namely lithium hydroxide, sodium hydroxide and potassium hydroxide was analyzed. The influence of surface morphology on capacitance and internal resistance was also determined and explained on the basis of redox reactions in these electrolytes. Capacitance values as high as 1024 Fg−1 was attained for these structures when employed as thin film electrodes with life extending to more than 5000 cycles. Inductively coupled plasma-atomic emission spectroscopy was used to determine the electrode dissolution in the given electrolyte and the observations were co-related with the cycling stability. Low self-discharge, high rate capability along with low cost makes them promising systems for supercapacitor applications.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 02/2015; 470. DOI:10.1016/j.colsurfa.2015.01.068 · 2.35 Impact Factor
  • Handbook of Clinical Nanomedicine: From Bench to Bedside, 01/2015; Pan Stanford Publishing., ISBN: 978-9814316170
  • [Show abstract] [Hide abstract]
    ABSTRACT: The present study demonstrates a novel approach by which ‘bulk nanostructured’ NiO micro bouquets can be processed into a high surface area electrode for supercapacitor applications. A detailed study has been performed to elucidate the impact of porosity and redox reactions on the electrochemical behavior. The spheres were synthesized using a soft template technique. An intrinsic correlation between the surface area, capacitance and the internal resistance has been deduced and explained on the basis of relative contributions from the faradic properties of NiO. These NiO spheres exhibited specific mass capacitance values as high as 1950 F g−1. Further, coin cells employing these rechargeable electrodes were also demonstrated which exhibits energy and power densities of 17 W h kg−1 and 24 kW kg−1. It has been shown that these electrodes based on such bulk nanostructures can allow significant room for high performance supercapacitor devices.
    Journal of Alloys and Compounds 01/2015; 618:396-402. DOI:10.1016/j.jallcom.2014.08.133 · 2.73 Impact Factor
  • Dhanya Narayanan, Shantikumar Nair, Deepthy Menon
    [Show abstract] [Hide abstract]
    ABSTRACT: Development of parenteral nanoformulations is highly challenging due to the stringent demands on stability, reproducibility and high drug loading with minimal excipients. This study focuses on the development of a pharmaceutically acceptable nanomatrix system for parenteral delivery based on Hydroxyethyl Starch (HES), a FDA approved polymer that is relatively unexplored in drug delivery research. HES nanoparticles were prepared through a simple, two-step crosslinking-precipitation route, yielding 160±5nm, nearly monodispersed spherical particles with high colloidal stability. The utility of this nanocarrier for parenteral delivery was verified by a panel of hemo/cytocompatibility assays at high concentrations (0.05-1mg/ml) in vitro and in vivo. HES nanomatrix was found effective in encapsulating two chemically distinct drugs having varying hydrophobicities, with the release behavior being influenced by their chemical nature and drug-matrix interactions. Better in vitro efficacy was measured for the nanoencapsulated drug than its bare form, establishing the potential of HES nanocarriers for controlled drug delivery. Copyright © 2014 Elsevier B.V. All rights reserved.
    International Journal of Biological Macromolecules 01/2015; 74. DOI:10.1016/j.ijbiomac.2014.12.012 · 3.10 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pancreatic cancer has an infaust prognosis and is the fourth common cause of cancer related death in India. It is highly resistant to conventional treatment modalities such as chemotherapy, radiation therapy and surgery. The association of pancreatic cancer and diabetes mellitus is explored in our study. Pancreatic cancer is more likely to occur in people who have diabetes than people devoid of it, which is supported by the observation that hyperglycaemia occurs at an early stage of pancreatic cancer and is indeed a risk factor. In the present study, we have demonstrated a synergistic relationship between metformin and boswellic acid nanoparticles with varying doses of boswellic acid nanoparticles and constant metformin (20 mM). The effect revealed increased synergism between metformin and boswellic acid nanoparticles through the inhibition of cell proliferation with an effect of 80% for the combination with 0.3 mg/mL and 0.4 mg/mL and a constant concentration of metformin. We examined the effect of combination on cell migration which revealed time dependent inhibitory effect on pancreatic cell line (MiaPaCa-2). Also, we found that the combinatorial approach significantly decreased colony formation and exhibited high rate of induction of apoptosis through DNA fragmentation in pancreatic cancer cells. In-vitro hemolysis confirmed the hemocompatibility of the combination therapy with metformin and boswellic acid nanoparticles. Flow cytometry based apoptosis assay and Caspase mediated apoptosis proved apoptosis mediated cell death. Further, the cells were analysed with mitochondrial membrane potential kit which revealed depolarization of mitochondrial membrane potential due to apoptosis after treatment with drug combination. Hence, the combination approach proved to be a promising therapy towards pancreatic cancer.
    Journal of Biomedical Nanotechnology 01/2015; 11(1):93-104. DOI:10.1166/jbn.2015.1877 · 7.58 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Standard in vitro drug testing employs 2-D tissue culture plate systems to test anti-leukemic drugs against cell adhesion-mediated drug-resistant leukemic cells that harbor in 3-D bone marrow microenvironments. This drawback necessitates the fabrication of 3-D scaffolds that have cell adhesion-mediated drug-resistant properties similar to in vivo niches. We therefore aimed at exploiting the known property of polyurethane (PU)/poly-l-lactic acid (PLLA) in forming a micro-nanofibrous structure to fabricate unique, not presented before, as far as we are aware, 3-D micro-nanofibrous scaffold composites using a thermally induced phase separation technique. Among the different combinations of PU/PLLA composites generated, the unique PU/PLLA 60:40 composite displayed micro-nanofibrous morphology similar to decellularized bone marrow with increased protein and fibronectin adsorption. Culturing of acute myeloid leukemia (AML) KG1a cells in FN-coated PU/PLLA 60:40 shows increased cell adhesion and cell adhesion-mediated drug resistance to the drugs cytarabine and daunorubicin without changing the original CD34(+)/CD38(-)/CD33(-) phenotype for 168 hours compared to fibronectin tissue culture plate systems. Molecularly, as seen in vivo, increased chemoresistance is associated with the upregulation of anti-apoptotic Bcl2 and the cell cycle regulatory protein p27(Kip1) leading to cell growth arrest. Abrogation of Bcl2 activity by the Bcl2-specific inhibitor ABT 737 led to cell death in the presence of both cytarabine and daunorubicin, demonstrating that the cell adhesion-mediated drug resistance induced by Bcl2 and p27(Kip1) in the scaffold was similar to that seen in vivo. These results thus show the utility of a platform technology, wherein drug testing can be performed before administering to patients without the necessity for stromal cells.
    International Journal of Nanomedicine 01/2015; 10:3603-22. DOI:10.2147/IJN.S80397 · 4.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Injectable, biodegradable scaffolds are required for soft tissue reconstruction owing to its minimally invasive approach. Such a scaffold can mimic the native extracellular matrix (ECM), provide uniform distribution of cells and overcome limitations like donor site morbidity, volume loss etc. So, here we report two classes of biocompatible and biodegradable hydrogel blend systems namely, Alginate/O-carboxymethyl chitosan (O-CMC) and Alginate/poly (vinyl alcohol) (PVA) with the inclusion of fibrin nanoparticles in each. The hydrogels were prepared by ionic cross-linking method. The developed hydrogels were compared in terms of its swelling ratio, degradation profile, compressive strength and elastic moduli. From these preliminary findings, it was concluded that Alginate/O-CMC formed a better blend for tissue engineering applications. The potential of the formed hydrogel as an injectable scaffold was revealed by the survival of Adipose Derived Stem Cells (ADSCs) on the scaffold by its adhesion, proliferation and differentiation into adipocytes. Cell differentiation studies of fibrin incorporated hydrogel scaffolds showed better differentiation was confirmed by Oil Red O staining technique. These injectable gels have potential in soft tissue regeneration. Copyright © 2014. Published by Elsevier B.V.
    International Journal of Biological Macromolecules 12/2014; 74. DOI:10.1016/j.ijbiomac.2014.12.037 · 3.10 Impact Factor

Publication Stats

4k Citations
916.32 Total Impact Points

Institutions

  • 2008–2015
    • Amrita Institute of Medical Sciences and Research Centre
      • Center for Nanosciences and Molecular Medicine
      Fort Cochin, Kerala, India
    • Amrita Vishwa Vidyapeetham
      • Amrita Center for Nanosciences & Molecular Medicine (ACNSMM)
      Koyambattūr, Tamil Nadu, India
  • 2009–2014
    • Amrita Institute of Medical Sciences
      Fort Cochin, Kerala, India
  • 2013
    • National University of Singapore
      Tumasik, Singapore