D. Durgalakshmi

University of Madras, Chennai, Tamil Nadu, India

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Publications (12)21.63 Total impact

  • D. Durgalakshmi · R. Ajay Rakkesh · S. Balakumar
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    ABSTRACT: We demonstrate an approach for Bioglass/TiO2 nanocomposites coatings onto the TiO2 nano-surfaces formed by etching of CP-Ti. The coated surface is further covered with Bioglass fibers to enhance the rate of apatite formation. Different concentrations of Bioglass/TiO2 composites are prepared by changing the TiO2 concentration. The coating is performed by electrophoretic deposition technique, and it shows less concentration of TiO2 gives higher adhesion to the substrates. The in vitro electrochemical corrosion and immersion studies confirm that the lower concentrations of TiO2 containing Bioglass/TiO2 composites coated sample possesses higher corrosion resistance and bio-mineralization that is highly suitable for bone osseointegration applications.
    No preview · Article · Sep 2015 · Applied Surface Science
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    Durgalakshmi D · Balakumar Subramanian
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    ABSTRACT: In the present work, sub micron sized hollow Bioglass 45S5 nanofibers are synthesised using electrospinning technique with the assistance of Poly vinyl pyrolidone polymer. The electrospinning process parameters are optimized to obtain reproducible nanofibers. The effect of solvent concentration and polymer concentrations affecting the morphology and formation of fibers. Ethanol and water is taken as source of concentration variant and the increase in the water dilution decreases the shell thickness of the hollow fibers. The mechanism of formation of hollow fibers is due to the phase separation occurs during physical cooling of the fibers. The equal ratio of ethanol and water diluted sol prepared fibers is showing higher performance in drug loading and releasing kinetics due to its narrow and linear size distribution. This fiber is also highly suitable for bone tissue engineering applications due to its linear fibrous 3D structural mat formation and suitable for large size scaling.
    Preview · Article · May 2015 · Physical Chemistry Chemical Physics
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    ABSTRACT: An increasing percentage of ageing population requires 30-year survivability of orthopedic devices that is not possible with the current bioinert materials, having a maximum of 15-year survivability. To satisfy this growing need, a shift is needed from replacement of tissues to regeneration of tissues. This is highly possible through the use of silica-bioactive glasses. However, a failure of implant can occur due to infections even by using such materials. Advances in using silver for antibacterial applications have been commercialized. However, higher concentrations of silver also lead to toxic effects. In this study, nanoBioglass 45S5 (NBG) and Ag-NBG were synthesized by using sol–gel method followed by solution-phase method, respectively. The bioactive crystals such as Na2Ca2Si3O9, CaCO3, and AgPO3, very much needed in the field of bone tissue engineering and in antibacterial strategies, were obtained in the NBG Matrix. The morphological investigation of NBG with 1 mM Ag+ concentrations shows the nanospikes arrangement of size 30–40 nm with spherical porous structure of size 10–20 nm, which supports the formation of collagen molecular fibrils on the surface of NBG matrices and enhances osseointegration. Both gram-positive and gram-negative strains show higher antibacterial activity for nanoBioglass with 1 mM Ag+ concentration.
    No preview · Article · Apr 2015 · Journal of Nanoscience and Nanotechnology
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    ABSTRACT: The GNS-V2O5/TiO2 composite, as a new class of nanoarchitecture, have been successfully fabricated by a facile hydrothermal process followed by a sol-gel technique. Such nanoarchitecture is made up of V2O5/TiO2 core/shell nanorods, chemically anchored on graphene nanosheets (GNS). High-resolution scanning transmission electron microscopy shows that these core/shell nanoparticles consist of core V2O5 nanorods of diameter 120 nm to 140 nm, covered by TiO2 shell of about 15 nm to 20 nm thickness. Large quantities of core/shell nanostructure materials are uniformly embedded on the surface of GNS. These new nanoarchitectures consists of two different kinds of metal oxides, that is V2O5 and TiO2 which are electrostatically coupled with each other and decorated on the GNS by chemical bonding between C-Ti confirmed by Zeta potential analyzer and XPS studies, respectively. The sunlight-active photocatalytic properties of the GNS-V2O5/TiO2 nanoarchitectures have been evaluated by photodegradation of acridine orange (AO) dye in an aqueous medium. Results show that the enhancement in the photocatalytic activity was attributed to the synergetic effect and also the chemical bonding leads to the interfacial charge transfer effect between GNS-semiconductor interfaces. It remarkably increases the spatial condition for charge transport and also increases the number of holes participating in the photodegradation process. This new nanoarchitecture exhibits an efficient photocatalytic activity and very high stability, holding great potential as a highly stable and reusable material for energy, water splitting, and environmental cleaning applications.
    Full-text · Article · Feb 2015 · RSC Advances
  • D. Durgalakshmi · R. Ajay Rakkesh · C. Ashok Raja · S. Balakumar
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    ABSTRACT: A large number of people have been affected due to fracture and other bone related diseases due to ageing, trauma, birth defects etc. Biomedical implants have been traditionally used in the field of orthopaedics to repair or replace the malfunctioning bone, alleviate pain, increase mobility and improve the quality of life of the patients. These implants due to several biological and mechanical factors lead to failure. The success rate of revision surgery is less compare to the primary surgery, the additional pain and the infection caused due to the primary surgery is also non negligible. Surface modifications techniques were extensively employed to address this problem. In the present work, 45S5 nanoBioglass (NBG)/titania (TiO₂) composites were coated on the surface of commercially pure titanium (CP-Ti) using electrophoretic deposition technique (EPD). Optimizing the parameters of the EPD coating is the major task for obtaining a uniform deposition. The effect of six processing parameters such as voltage, deposition time, distance of separation between anode and cathode, particle loading, presence of binder, substrate roughness were studied using Design of Experiment (DOE) approach. It was shown that the three parameters such as quantity of particle loading of NBG/TiO2 in the electrolyte, voltage applied to the electrode as well as nature of the binder added to the electrolyte affects the formation of crack free, thick, and uniform coating on CP -Ti substrate. © 2015, International Journal of ChemTech Research. All rights reserved.
    No preview · Article · Jan 2015 · International Journal of ChemTech Research
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    D. Durgalakshmi · S.P. Subhathirai · S. Balakumar
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    ABSTRACT: Bioactive-glass scaffolds are crucial in bone tissue engineering since they act as temporary templates for tissue regrowth, providing structural support to the cells. The enhancement of the angiogenic potential of implantable biomaterial scaffolds is receiving much attention in tissue engineering strategies. The angiogenic potential of most synthetic and natural materials used to fabricate tissue-engineered scaffolds is limited, insufficient, or even absent, numerous attempts have been made to enhance angiogenesis associated with tissue-engineered constructs, either by changing physicochemical properties or by supplementation with angiogenic factors. In order to improve the angiogenic effect of bioglass nano potash alum was incorporated to the Bioglass. Both Bioglass and alum doped Bioglass were synthesised by wet chemical method (sol-gel method) and its physiological properties were studied using TGA, XRD, FESEM, its cytocompatibility was studied by in vitro cell culture studies, and these bioglass are able to form a hydroxycarbonate apatite layer on their surface when in contact with an aqueous solution.
    Full-text · Article · Dec 2014 · Procedia Engineering
  • A. Pavithra · R. Ajay Rakkesh · D. Durgalakshmi · S. Balakumar
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    ABSTRACT: High quality Graphene Nanosheets (GNS) are being fabricated by chemical vapour deposition (CVD) process from naturally occurring carbon source (camphor). The decomposition of camphor on Si wafer by CVD technique is systematically investigated. X-Ray Diffraction and Confocal Raman Studies confirm the formation of GNS on Si wafer. The topography of the grown GNS is imaged by means of Field emission scanning electron microscopy, which demonstrates that the Si surface is covered with continuous and wrinkled graphene carpets. X-ray photoelectron spectroscopic analysis further confirms the existence of graphite layers and the absence of any other spectral features associated with carbides. The facile CVD process is an appropriate method for large scale production of graphene Nanosheets with naturally occurring camphor.
    No preview · Article · Dec 2014
  • D Durgalakshmi · S Balakumar
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    ABSTRACT: Mimicking three dimensional microstructural scaffolds with their requisite mechanical properties in relation to human bone is highly needed for implant applications. Various biocompatible polymers and bioactive glasses were synthesized to achieve these properties. In the present study, we have fabricated highly porous and bioactive PMMA-Bioglass scaffolds by the phase separation method. Chloroform, acetone and an ethanol-water mixture were used as the different solvent phases in preparing the scaffolds. Large interconnecting pores of sizes ∼100 to 250 μm were observed in the scaffolds and a porosity percentage up to 54% was also achieved by this method. All samples showed a brittle fracture with the highest modulus of 91 MPa for the ethanol-water prepared scaffolds. The bioactivities of the scaffolds were further studied by immersing them in simulated body fluid for 28 days. Scanning electron microscopy, X-ray diffraction and Raman spectra confirmed the formation of bioactive hydroxyl calcium apatite on the surfaces of the scaffolds.
    No preview · Article · Nov 2014 · Physical Chemistry Chemical Physics
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    ABSTRACT: Recently, Graphene nanosheets (GNS) decorated semiconductor photocatalysts have received more attention because of their enhanced photocatalytic activity caused by varying the band gap energy and interfacial charge transfer effect. However, the effects of band gap variation and interfacial charge transfer are rarely involved in the chemical bonding formation between GNS and semiconductors. In this paper, we report the fabrication of GNS-TiO2 and GNS-ZnO nanostructures with a chemically bonded interface by modified Hummer’s method. The chemically bonded GNS-TiO2 and GNS-ZnO nanostructures greatly enhanced their photocatalytic activity by photodegradation of methylene blue (MB) dye in an aqueous medium. The band gap energy value of the GNS-TiO2 and GNS-ZnO were found to be 1.39 eV and 1.26 eV, respectively, confirmed by UV-DRS analysis. The enhancement in the photocatalytic activity was attributed to the synergetic effect and also to the chemical bonding between GNS-semiconductor interfaces. It remarkably decreased the recombination rate and also increased the number of holes participating in the photodegradation process, confirmed by XPS analysis. This work can provide a revelation for designing the new heterogeneous photocatalysts, which can be used in energy, water splitting, and environmental cleaning applications.
    No preview · Article · Jun 2014
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    ABSTRACT: Implants made out of Ti alloys often fail due to their lower wear and corrosion resistance. In order to obviate this problem, submicrometric diamond films were grown on Ti–13Nb–13Zr and Ti–23Nb–0.7Ta–2Zr–O (Gum metal) using hot filament chemical vapor deposition technique. Deposited films were characterized using XRD, Raman, SEM, AFM and nanointender. The electrochemical corrosion and reciprocatory wear behavior of the coated samples were evaluated in simulated body fluid. The results demonstrate that corrosion and wear properties of the diamond coated Gum metal are far superior than Ti–13Nb–13Zr alloy, due to the presence of beta phase in the former alloy.
    Full-text · Article · Jul 2013 · Tribology International
  • D. Durgalakshmi · S. Balakumar
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    ABSTRACT: Bioglass 45S5 possess excellent bioactivity and is regarded as a promising next-generation bone regenerative material. The formulation of Bioglass is limited to bulk, crushed powders and micro-scale fibers. Compare to bulk, Nanoscale Bioglass will enhance the osseo-integration to the extracellular matrix. Nano-Bioglass (NBG) 45S5 synthesized using sol-gel technique without any catalysts is reported in this paper. The thermal behavior of the as prepared bioglass was studied using TGA-DSC analysis and the sintering temperature was selected as 600°C. The precious XPS results shows good correlation with XRD results especially in the formation of Ca 3 2− groups. The Spherical nanostructures of size ∼45-50nm has been imaged using FESEM analysis. The cytotoxity studies was done using fibroblast 3T3 cell lines and the results shows that the fibroblast growth is less compare to control which supports the high bone formation in in vitro.
    No preview · Article · Feb 2013
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    ABSTRACT: This paper reports on the corrosion and scratch behavior of TiO2 + 50%HAp nanoceramic coated Ti–13Nb–13Zr orthopedic implant alloy. An adherent thin coating was obtained using the electrophoretic deposition (EPD) technique at 30 V and sintering at 850 °C. The microstructure of the coated surfaces was characterized by optical microscopy, AFM, and SEM, and the composition of the coating was examined using EDAX. The functional groups and formed phases analyzed using FT-IR, and XRD. Further, the adhesion strength of the coatings was evaluated using scratch tester and the corrosion behavior of all samples was tested in Simulated Body Fluid (SBF-Hank's solution) using a potentiodynamic polarization studies. The sintered coating exhibited higher adhesion, lower porosity and higher density compared to unsintered samples, and higher corrosion resistance compared to the substrate. However, the corrosion resistance of the unsintered coating was superior to that of the sintered one due to the presence of minimal interconnected porosity.
    Full-text · Article · May 2012 · Ceramics International

Publication Stats

33 Citations
21.63 Total Impact Points


  • 2013-2015
    • University of Madras
      • Centre for Nanosciences and Nanotechnology
      Chennai, Tamil Nadu, India
    • VIT University
      • School of Advanced Sciences (SAS)
      Velluru, Tamil Nādu, India