Two-in-One Biointerfaces-Antimicrobial and Bioactive Nanoporous Gallium Titanate Layers for Titanium Implants.

The inhibitory effect of gallium (Ga) ions on bone resorption and their superior microbial activity are attractive and sought-after features for the vast majority of implantable devices, in particular for implants used for hard tissue. In our work, for the first time, Ga ions were successfully incorporated into the surface of titanium metal (Ti) by simple and cost-effective chemical and heat treatments. Ti samples were initially treated in NaOH solution to produce a nanostructured sodium hydrogen titanate layer approximately 1 μm thick.

Nanomechanical responses of human hair.

Here we report the first ever studies on nanomechanical properties e.g., nanohardness and Young׳s modulus for human hair of Indian origin.

Controlled release of strontium ions from a bioactive Ti metal with a Ca-enriched surface layer.

A nanostructured sodium hydrogen titanate layer ∼1μm in thickness was initially produced on the surface of titanium metal (Ti) by soaking in NaOH solution. When the metal was subsequently soaked in a mixed solution of CaCl2 and SrCl2, its Na ions were replaced with Ca and Sr ions in an Sr/Ca ratio in the range 0.18-1.

An X-ray micro-fluorescence study to investigate the distribution of Al, Si, P and Ca ions in the surrounding soft tissue after implantation of a calcium phosphate-mullite ceramic composite in a rabbit animal model.

Synthetic calcium phosphates, despite their bioactivity, are brittle. Calcium phosphate- mullite composites have been suggested as potential dental and bone replacement materials which exhibit increased toughness. Aluminium, present in mullite, has however been linked to bone demineralisation and neurotoxicity: it is therefore important to characterise the materials fully in order to understand their in vivo behaviour.

In vitro biocompatibility of novel biphasic calcium phosphate-mullite composites.

In designing new calcium phosphate (CaP)-based composites, the improvement in physical properties (strength, toughness) without compromising the biocompatibility aspect is essential. In a recent study, it has been demonstrated that significant improvement in compressive strength as well as modest enhancement in toughness is achievable in biphasic calcium phosphate (BCP)-based composites with mullite addition (up to 30 wt%). Herein, we report the results of the in vitro cell adhesion, cell proliferation, alkaline phosphatase (ALP) activity, and osteocalcin (OC) production for a series of BCP-mullite (up to 30 wt%) composites.

Mechanical properties of novel calcium phosphate-mullite biocomposites.

Herein, the results of systematic mechanical property measurements of pressureless sintered calcium phosphate (CaP)-mullite composites are discussed. Our experimental results demonstrated how the mullite addition (upto 30 wt%) influenced hardness, elastic modulus, strength and toughness properties of the composites. In assessing each of these fundamental material properties, either a range of load or a number of complimentary techniques were used to obtain reliable measure of mechanical properties.

In vitro dissolution of calcium phosphate-mullite composite in simulated body fluid.

In our recent research, we have developed novel CaP-mullite composites for bone implant applications. In order to realize such applications, the in vitro dissolution behaviour of these materials needs to be evaluated. In this perspective, the present paper reports the dissolution behavior of pure hydroxyapatite (HAp) and hydroxyapatite composites with 20-30 wt% mullite in simulated body fluid (SBF).

Fretting wear behavior of calcium phosphate-mullite composites in dry and albumin-containing simulated body fluid conditions.

In a recent work, it has been shown that it is possible to achieve a better combination of compressive strength, flexural strength and toughness properties in calcium phosphate (CaP) composites containing 20 and 30 wt% mullite (3Al(2)O(3).2SiO(2)). In view of their potential application as load bearing implants, the present work reports the friction and wear properties of the newly developed composites against zirconia under dry ambient as well as in simulated body fluid (SBF) containing bovine serum albumin (BSA) protein.

Densification, phase stability and in vitro biocompatibility property of hydroxyapatite-10 wt% silver composites.

In this paper, we demonstrate how a simple fabrication route, i.e., pressureless sintering of mechanically mixed powders can be employed to develop hydroxyapatite (HAp, Ca(10)(PO(4))(6)(OH)(2))-silver (Ag) bioceramic composites with superior combination of physical (hardness, toughness), non-cytotoxicity, cytocompatiblity and anti-microbial property.

Phase assemblage study and cytocompatibility property of heat treated potassium magnesium phosphate-silicate ceramics.

This article reports the study on a new generation bioactive ceramic, based on MgKPO(4) (Magnesium Potassium Phosphate, abbreviated as MKP) for biomedical applications. A series of heat treatment experiments on the slip cast silica (SiO(2)) containing MKP ceramics were carried out at 900, 1,000 and 1,100 degrees C for 4 h in air. The density of the slip cast ceramic increases to 2.

In vivo response of novel calcium phosphate-mullite composites: results up to 12 weeks of implantation.

In this paper, the in vivo response, in particular, the histocompatibility of newly developed CaP-mullite composites is reported. In the present experiments, the bioceramic implants were inserted in the long bones of healthy rabbits according to standard protocols (ISO-10993) and the tissue response was studied at different time intervals of up to 12 weeks. Ultra high-molecular weight polyethylene (UHMWPE) was used as control samples.

Friction and wear properties of novel HDPE--HAp--Al2O3 biocomposites against alumina counterface.

In an effort to enhance physical properties of biopolymers (high-density polyethylene, HDPE) in terms of elastic modulus and hardness, various ceramic fillers, like alumina (Al2O3) and hydroxyapatite (HAp) are added, and therefore it is essential to assess the friction and wear resistance properties of HDPE biocomposites. In this perspective, HDPE composites with varying ceramic filler content (upto 40 vol%) were fabricated under the optimal compression molding conditions and their friction and wear properties were evaluated against Al2O3 at fretting contacts. All the experiments were conducted at a load of 10 N for duration of 100,000 cycles in both dry as well as simulated body fluid (SBF).

HDPE-Al2O3-HAp composites for biomedical applications: processing and characterizations.

The objective of this work is to demonstrate how the stiffness, hardness, as well as the biocompatibility property, of bioinert high-density polyethylene (HDPE) can be significantly improved by the combined addition of both bioinert and bioactive ceramic fillers. For this purpose, different volume fractions of hydroxyapatite and alumina, limited to a total of 40 vol %, have been incorporated in HDPE matrix. All the hybrid composites and monolithic HDPE were developed under optimized hot pressing condition (130 degrees C, 0.

Fretting wear properties of hydroxyapatite, alumina containing high density polyethylene biocomposites against zirconia.

Considering the importance of wear on the materials performance in biomedical applications, the major objective of the present work is to investigate the friction and fretting wear behavior of various HDPE-based composites against zirconia counterbody, both in air and simulated body fluid (SBF) environment. Both Al(2)O(3) and/or HAp fillers (upto 40 vol %) have been incorporated in HDPE to improve the hardness and elastic modulus of HDPE. The fretting wear study indicates that extremely low COF (approximately 0.

Tribological investigation of novel HDPE-HAp-Al2O3 hybrid biocomposites against steel under dry and simulated body fluid condition.

Among various biocompatible polymers, polyethylene based materials have received wider attention because of its excellent stability in body fluid, inertness, and easy formability. Attempts have been made to improve their physical properties (modulus/strength) to enable them to be used as load bearing hard tissue replacement applications. Among such attempts, high density polyethylene (HDPE)-hydroxyapatite (HAp) composite (HAPEX), has already been developed for total hip replacement (THR) acetabular cup and low load bearing bone tissue replacement.