Synthesis and characterization of nano-grained hydroxyapatite through slip casting technique

Nano hydroxyapatite (HAp) more closely mimics the size of HAp crystals in natural bone and teeth. Due to high surface energy, nano-sized HAp powder can result in better sinterability and, therefore improve mechanical properties. In this present work, nano particle hydroxyapatite was prepared using two methods, wet chemical method and ammoniacal method. The as prepared powder and calcined powder was characterized by XRD, FTIR to study the phases of the powders. 50 vol slurry was prepared using powders calcined at 1000°C for 2 hours and sodium polyacrylate was used as deflocculating agent. After slip casting in Plaster of Paris mould, the green samples were sintered at different temperature 1100, 1200, 1250 and 1300°C for 2 hours to study the sintering behavior. Physical, mechanical and biological characterization was done for the sintered samples. © 2010 IEEE

Development of nano-grained Calcium Hydroxyapatite using slip casting technique

The purpose of this study is to synthesize nano-grained Calcium Hydroxyapatite (HAp) through slip casting technique. For this, hydroxyapatite powders were synthesized using two methods, wet chemical method and Ammoniacal method. The as-prepared powders and calcined powders were characterized using XRD, FTIR, to study the phases of the powders. The hydroxyapatite powder calcined at 1000°C for 2hr was used to prepare 50 vol% slurry using DN40 (sodium polyacrylate) as dispersing agent. After slip casting, the green bodies were sintered at different temperatures, 1100, 1200, 1250 and 1300°C with 2hr soaking time. The sintered dense samples were characterized for physical, mechanical and biological behavior

MG63 osteoblast cell response on Zn doped hydroxyapatite (HAp) with various surface features

The clinical success of implant is governed by implant-surface and bone cell interaction that promote osseointegration and long term stability. Calcium hydroxyapatite (HAp) is a widely used bioceramic material for orthopedic and dental applications, which promotes bone tissue generation. Doped hydroxyapatite using various metallic ions is often reported to enhance this osteoconductive property. The objective of this study was to synthesize zinc doped HAp, to investigate the osteoblast cell response on this doped HAp and find out separately the effect of doping and different surface parameters on cell response. Slip casting technique was used to prepare pure and doped HAp specimens which were sintered at 1100 degrees C and 1250 degrees C. Different porosities, pore sizes were generated along with different surface roughness so as to understand the effect of these extrinsic parameters on cell culture. MG63 osteoblast cells were used for a maximum period of two weeks. Metabolic activity, adhesion and proliferation rate study of osteoblast cells on doped HAp showed significantly better response than pure HAp. Effect of doping was found to be more prominent than the effect of surface roughness

Animal trial on zinc doped hydroxyapatite: A case study

Calcium hydroxyapatite (HAp) has widely been used as bone substitute due to its good biocompatibility and bioactivity. In the present work, hydroxyapatite was doped with zinc (Zn) to improve its bioactivity. The study reports the technique to synthesize Zn-doped HAp powder using a simple, economic route and the influence of this dopant on the physical, mechanical and biological properties of the HAp. Porous blocks were prepared by sintering at 1150 °C and the sintered samples were characterized using XRD and FTIR. In vitro bioresorption behavior of the sintered blocks was assessed in simulated body fluid (SBF) maintained in a dynamic state. The in vivo study was exclusively conducted to evaluate healing of surgically created defects on the tibia of adult New Zealand rabbit after implantation of HAp. Local inflammatory reaction and healing of wound, radiological investigations, histological and SEM studies, oxytetracycline labeling and mechanical push-out test were performed up to 60 days post-operatively. It was observed that Zn substituted HAp showed better osteointegration than undoped HAp. Radiology revealed progressively less contrast between implant and surrounding bone. New bone formation in Zn-doped HAp was more prompt. Mechanical push-out test showed high interfacial strength (nearly 2.5 times) between host bone and doped implant

Effect of bone morphogenetic protein on Zn-HAp and Zn-HAp/collagen composite: A systematic in vivo study

Due to good biocompatibility and osteoconductivity, hydroxyapatite (HAp) and its composite with different polymers have been widely investigated for the application in the field of bone tissue engineering. The present study reports the, in vivo performance of zinc doped HAp and HAp/collagen composite (HAC) using bone morphogenetic protein-2. It was done for a span of two months on New Zealand rabbit model. After two months postoperatively, there was no marked inflammatory reaction in experimental groups and control groups. The histological images showed well-formed bony matrix with well differentiated haversian system. From the fluorochrome labeling study, it was observed that higher amount of new bone formed in case of bone morphogenetic protein-2 (BMP-2) loaded Zn-HAp (50%) and HAC (27%) specimens than control. The percentage of new bone formation was significantly higher in case of BMP loaded Zn-HAp group than BMP loaded HAC group. From the SEM images similar trend was observed. As the HAC specimen consists of amorphous phase, it had a negative impact on new bone formation. (C) 2017 Elsevier Ltd. All rights reserved

Strategies for delivering bone morphogenetic protein for bone healing

Bone morphogenetic proteins (BMPs) are the most significant growth factors that belong to the Transforming Growth Factor Beta (TGF-beta) super-family. Though more than twenty members of this family have been identified so far in humans, Food and Drug Administration (FDA) approved two growth factors: BMP-2 and BMP-7 for treatments of spinal fusion and long-bone fractures with collagen carriers. Currently BMPs are clinically used in spinal fusion, oral and maxillofacial surgery and also in the repair of long bone defects. The efficiency of BMPs depends a lot on the selection of suitable carriers. At present, different types of carrier materials are used: natural and synthetic polymers, calcium phosphate and ceramic-polymer composite materials. Number of research articles has been published on the minute intricacies of the loading process and release kinetics of BMPs. Despite the significant evidence of its potential for bone healing demonstrated in animal models, future clinical investigations are needed to define dose, scaffold and route of administration. The efficacy and application of BMPs in various levels with a proper carrier and dose is yet to be established. The present article collates various aspects of success and limitation and identifies the prospects and challenges associated with the use of BMPs in orthopaedic surgery. (C) 2016 Elsevier B.V. All rights reserved