Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

The biomimetic apatite in chitosan spongy scaffold was studied at room temperature. Chitosan sponges were prepared by freeze drying method. The acetic acid-chitosan solution was cast in polyethylene plates and freezed and freeze dried at -80°C and -35°C. The result from X ray diffraction analysis shows the broad characteristic peak in the region of 30°C, showing the formation of apatite phase. The mineralized scaffolds were found to be nocytotoxic and the cells proliferation and growth was better than unmineralized scaffolds.

Department of Bio-Sciences

School of Bio Sciences and Technology

Vellore Campus

World University root node

Transactions - 7th World Biomaterials Congress

Invitro cytocompatibility study of biomimetic apatite incorporated in chitosan spongy scaffold

European Cells and Materials

Adhesion and Proliferation of Osteoblastic cells seeded on chitosan - hydroxyapatite porous scaffolds

Synthetic hydroxyapatite (HA) and tricalcium phosphate (TCP) are promising bone-substitute materials in the orthopaedic and dental fields, as their chemical composition is similar to that of bone. This study investigated the osseointegration performance of carbonated biphasic calcium phosphate (CBCP) ceramics containing carbonated hydroxyapatite and tricalcium phosphate prepared by microwave irradiation, in femoral defects of dogs. The defects were created as 3-mm holes on the lateral aspect of femur and filled with the implant material. The serum was collected postoperatively and biochemical assays for alkaline phosphatase activity levels were carried out. The animals' defective sites were radiographed at 4, 8, and 12 weeks. The radiographic results showed that the process of ossification started after 4 weeks and the defect was completely filled with new bone after 8 weeks. Histological examination of the tissue showed the osteoblastic activity inducing the osteogenesis in the defect. The complete haversian system with osteoblastic and osteoclastic activity and bone remodelling process were observed after 12 weeks. The alkaline phosphatase activity levels also correlated with the formation of osteoblast cells. This calcium phosphate ceramic has proved to work well as a biocompatible implant and as an osteoconductive and osteoinductive material for the filling of bone defects. © 2002 John Wiley & Sons, Inc.

Journal of Biomedical Materials Research

Bioactivity and osseointegration study of calcium phosphate ceramic of different chemical composition

Composite microspheres have been prepared from bioactive ceramic such as coralline hydroxyapatite [Ca10(PO4)6(OH)2] granules, a biodegradable polymer, chitosan and an antibiotic, gentamicin. In our earlier work, we have shown a simple method of converting the calcium carbonate skeleton of the Indian corals into hydroxyapatite granules. The composite microspheres containing coralline hydroxyapatite and chitosan were prepared by dispersion polymerization technique and the gentamicin was incorporated by absorption method. The crystal structure of the composite microspheres was analyzed using X-ray powder diffractometer. The Fourier transformed infrared spectra clearly indicated the presence of amide and hydroxyl groups in the composite microspheres. Scanning electron micrographs and optical micrographs shows that the composite microspheres are spherical in shape and porous in nature. The particle size of composite microspheres was analyzed and the average size was found to be 18microns. The thermal behavior of composite microspheres was studied using thermogravimetric analysis and differential scanning calorimetric analysis. The cumulative in-vitro release profile of gentamicin from composite microspheres showed near zero order patterns. © 2002 Elsevier Science Ltd. All rights reserved.

Carbohydrate Polymers

Preparation, characterization and in-vitro release of gentamicin from coralline hydroxyapatite-chitosan composite microspheres

The calcium phosphate ceramics are widely used as bone substitute material. The functional gradient form of calcium phosphate offers advantages of continuous dissolution of calcium ions along with the osteoconductivity. The functional gradient of calcium phosphate in the present study is formed by the controlled partial decomposition of hydroxyapatite using titania and silver oxide. The FGM was characterised by x-ray diffraction techniques for phase analysis and scanning electron microscope for morphology analysis.

Key Engineering Materials

Structural and morphological analysis of functionally graded calcium phosphate bioceramic

In situ synthesis of biphasic calcium phosphate doped with magnesium fluoride using microwave irradiation was carried out. The powders were analyzed using X-ray diffractometer and monochromatic radiation. Stability of the powders was examined by infrared spectra. The use of the compound in osteoporotic applications was discussed.

Journal of Materials Science Letters

Preparation of biphasic calcium phosphate doped with magnesium fluoride for osteoporotic applications

Hydroxyapatite (HA) and fluoroapatite (FHA) have been widely investigated as bone substitute and replacement materials. We report here the preparation of hydroxy/fluoroapatite solid solution using wet chemical precipitation method via brushite hydrolysis. Various amounts of sodium fluoride (1-5 mol%) were added during the preparation of hydroxyapatite to form hydroxy/fluoroapatite solid solution. The various experimental techniques like XRD, DTA, TGA, FT-IR and Vicker's hardness measurements were used to characterize the synthesized powders. Thermal analysis of the samples shows only the decomposition reaction of residues formed and the corresponding weight loss due to these reactions. The XRD data of all the samples calcined at 900°C shows well defined peaks of hydroxyapatite and fluoroapatite. The merging of (211) and (112) peak of apatite lattice in the FHA pattern indicates the formation of hydroxy/fluoroapatite solid solution. The decrease in the a-axis of HA lattice parameter indicates the substitution of F- ion in the OH- site of HA lattice. The FT-IR spectroscopic studies of the samples confirms the substitution of the F- ion in the OH- site of the HA lattice. The Vicker's hardness measurement shows that the hardness value of hydroxy/fluoroapatite solid solution is greater than the hydroxyapatite.

Journal of Materials Science

Synthesis and characterisation of hydroxy/fluoroapatite solid solution

Hydroxyapatite (HA) has been widely used in the field of orthopaedics and dentistry. Due to HA's lack of mechanical properties, composites containing hydroxyapatite and zirconia have been suggested for the purpose of increasing strength and fracture toughness. This paper reports the preparation of fluorine-doped hydroxyapatite from Indian coast corals and zirconia composites using coralline hydroxyapatite and coralline fluoroapatite. The fluoroapatite and composites were prepared by two methods: (i) low temperature (LT) or hydrothermal method and (ii) high temperature (HT) or solid state reaction method. These materials were characterized by X-ray diffraction (XRD) analysis, Fourier-transform infrared spectroscopy (FT-IR) and thermal analysis. Decrease in the a-axis of HA lattice was observed in the fluoroapatite, suggesting partial fluorination of hydroxyapatite resulting in hydroxy/fluoroapatite solid solution. The analysis of the composites shows the formation of β-tricalcium phosphate due to the decomposition of hydroxyapatite. © 2001 Elsevier Science B.V. All rights reserved.

Materials Letters

Preparation of hydroxyapatite/fluoroapatite-zirconia composites using Indian corals for biomedical applications

Microwave synthesis of ceramics offers the advantage of efficient transformation of energy and heating throughout the volume efficiently in shorter period leading to fine crystallites. Hydroxyapatite (HA) and tricalcium phosphate (TCP) are widely used in the field of medicine and dentistry. Recently, biphasic calcium phosphate (BCP) ceramics has been paid attention as an ideal bone substitute due to its controlled degradability. In this paper, we report the in situ formation of BCP ceramic consisting of a mixture of HA and β-TCP in various ratios synthesized under microwave irradiation. The BCP powders were characterized by various techniques like DTA, TGA, XRD and FTIR. The thermal stability of the BCP powders was determined using differential thermal analyser and thermogravimetric analyser. The X-ray diffraction pattern of BCP powders shows the in situ formation of β-TCP in BCP powder. The amount of β-TCP phase increases as the Ca/P ratio decreases from 1.67 to 1.52. The Fourier transformed infrared spectroscopy analysis also confirmed the BCP formation. The in vitro solubility study of BCP powders in phosphate buffer of pH 7.2 showed the resorbable nature of the BCP ceramics. The present study demonstrates the feasibility of in situ formation of BCP ceramics using a domestic microwave oven. © 2001 Elsevier Science B.V. All rights reserved.

Materials Chemistry and Physics

In-situ synthesis of biphasic calcium phosphate ceramics using microwave irradiation

The combined effect of titanium dioxide and silver oxide on the in situ formation of biphasic calcium phosphate ceramics was investigated. Titania (5-20mol%) was mixed with pure hydroxyapatite (HA) or HA containing Ag2O (10-20mol%) and was heated to 900°C for 12h. The sintered samples were found to contain tricalcium phosphate (β-TCP) and other phases along with HA depending upon the amount as well as the type of the additives used as evidenced by X-ray powder diffraction (XRD) and fourier transform infrared (FT-IR) spectroscopic studies. Enhanced TCP formation with reduced impurity phases was observed with TiO2-Ag2O addition. In vitro solubility study in phosphate buffer at physiological conditions shows the resorbable nature of these materials. A functionally graded material (FGM) structure was formed by spreading TiO2-Ag2O mixture on the surface of the HA green compact and heating at 900°C. The FGM shows gradient structure of TCP and HA from the surface to the interior of the pellet in addition to titania and silver phases. Copyright (C) 2000 Elsevier Science Ltd. The combined effect of titanium dioxide and silver oxide on the in situ formation of biphasic calcium phosphate ceramics was investigated. Titania (5-20 mol%) was mixed with pure hydroxyapatite (HA) or HA containing Ag2O (10-20 mol%) and was heated to 900 °C for 12 h. The sintered samples were found to contain tricalcium phosphate (β-TCP) and other phases along with HA depending upon the amount as well as the type of the additives used as evidenced by X-ray powder diffraction (XRD) and fourier transform infrared (FT-IR) spectroscopic studies. Enhanced TCP formation with reduced impurity phases was observed with TiO2-Ag2O addition. In vitro solubility study in phosphate buffer at physiological conditions shows the resorbable nature of these materials. A functionally graded material (FGM) structure was formed by spreading TiO2-Ag2O mixture on the surface of the HA green compact and heating at 900 °C. The FGM shows gradient structure of TCP and HA from the surface to the interior of the pellet in addition to titania and silver phases.

Biomaterials

Effect of TiO2-Ag2O additives on the formation of calcium phosphate based functionally graded bioceramics

Carbonated hydroxyapatites (CHA) were synthesized by the substitution of calcium carbonate for calcium hydroxide during the reaction with diammonium phosphate under microwave irradiation. The X-ray powder diffraction analysis indicates the decrease of a-axis up to 20mol% of carbonate substitution confirming the formation of the B-type CHA. Further increase of carbonate content shows the presence of tricalcium phosphate (TCP) in addition to CHA. Reaction of substituted magnesium carbonate instead of calcium carbonate in the above process results in the formation of biphasic calcium phosphate (BCP) ceramics consisting of both CHA and TCP phases. Fourier transform infrared spectroscopic study also confirmed the carbonate substitution in HA and BCP formation. The in vitro solubility study in phosphate buffer of pH 7.2 at 37°C showed the resorbable nature of the BCP samples. The present study thus indicates the feasibility of in situ formation of BCP ceramics using microwave irradiation. (C) 2000 Elsevier Science Ltd. Carbonated hydroxyapatites (CHA) were synthesized by the substitution of calcium carbonate for calcium hydroxide during the reaction with diammonium phosphate under microwave irradiation. The X-ray powder diffraction analysis indicates the decrease of a-axis up to 20 mol% of carbonate substitution confirming the formation of the B-type CHA. Further increase of carbonate content shows the presence of tricalcium phosphate (TCP) in addition to CHA. Reaction of substituted magnesium carbonate instead of calcium carbonate in the above process results in the formation of biphasic calcium phosphate (BCP) ceramics consisting of both CHA and TCP phases. Fourier transform infrared spectroscopic study also confirmed the carbonate substitution in HA and BCP formation. The in vitro solubility study in phosphate buffer of pH 7.2 at 37°C showed the resorbable nature of the BCP samples. The present study thus indicates the feasibility of in situ formation of BCP ceramics using microwave irradiation.

Synthesis of carbonated calcium phosphate ceramics using microwave irradiation

The partial conversion of coralline hydroxyapatite (HA) into tricalcium phosphate (TCP) catalyzed by the thermal decomposition of silver oxide was investigated. The thermal analysis of HA powder mixed with 5 mol % Ag2O indicated the decomposition of silver oxide to be around 550°C in the presence of HA. Subsequently a functional gradient structure was formed by spreading silver oxide on one surface of the HA compact of diameter 10 mm and then firing at 700 °C in air. The X-ray powder diffraction analysis confirmed the formation of α-TCP induced by the Ag2O decomposition. The content of α-TCP of the sintered pellet was found to decrease with the increasing depth from the surface of the pellet. In vitro solubility study in phosphate buffer of pH 7.2 showed the stability of the biphasic material as in between HA and TCP. (C) 2000 Kluwer Academic Publishers. The partial conversion of coralline hydroxyapatite (HA) into tricalcium phosphate (TCP) catalyzed by the thermal decomposition of silver oxide was investigated. The thermal analysis of HA powder mixed with 5 mol % Ag2O indicated the decomposition of silver oxide to be around 550 °C in the presence of HA. Subsequently a functional gradient structure was formed by spreading silver oxide on one surface of the HA compact of diameter 10 mm and then firing at 700 °C in air. The X-ray powder diffraction analysis confirmed the formation of α-TCP induced by the Ag2O decomposition. The content of α-TCP of the sintered pellet was found to decrease with the increasing depth from the surface of the pellet. In vitro solubility study in phosphate buffer of pH 7.2 showed the stability of the biphasic material as in between HA and TCP.