Graphical abstract of novel 5%@Ag:HAP–Fe3O4–CS hybrid composites and biological investigations.

Anjaneyulu G-S-G-N

Department of Mathematics

School of Advanced Sciences

Vellore Campus

Vijayalakshmi U

Department of Chemistry

Swaroop V.K

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

RSC Advances

Hydroxyapatite doped with disparate ions is synthesized by Sol-gel technique. Hydroxyapatite is a widely bio-ceramic material for orthopedics and dental applications with weak mechanical strength. The hydroxyapatite doped with various ions which is often reported to enhance mechanical strength and to control bacterial infections. The aim of the work concentrates to improve the hardness of the material. Antibacterial activity enhances with the ions which combine with hydroxyapatite. These effects noticeably reveal that the hydroxyapatite can be well utilized with doping ions in order to develop their efficiency against the various bacterial strains. The effect of co-dopants investigated on their phase structure, bond formation, surface and optical properties are studied using X-ray diffraction technique, Fourier Transform Infra-red analysis, Atomic Force Microscopy and Ultraviolet–Visible spectroscopy. The crystalline size of all the synthesized materials varies from 39 to 49 nm. All the composites exhibit hexagonal crystal structure. The functional groups confirm the bonding formation of prepared samples. The surface roughness of hydroxyapatite were successfully analyzed and observed that the dopants increase the roughness. The dielectric property explains the space charge polarization is present at low frequency and negative temperature coefficient of resistance in the prepared samples. The addition of ions improves the mechanical properties of host materials, which well suitable for coating on implantation devices and for various medical applications. © 2019 Elsevier B.V.

Materials Chemistry and Physics

Study of structural, mechanical and dielectrical properties of ions doped apatite for antibacterial activity

In the past few years, magnetic nano-particles (magnetite) have captured more attention in the field of biomaterial world.Various methods have been adopted for its synthesis,of which a simple, low temperature co-precipitation method was selected and adopted.Synthesized iron oxide magnetic nano-particles encounter limitations such as insolubility, aggregation, high reactivity and biodegradation in biological medium. To enhance the magnetic properties with various limitations, functionalization or encapsulation within the shell by way of surface coating has been recently appreciated by medical scientists. Functionalization or coating by silica has more and easily carried out by sol-gel technique. The encapsulated, core magnetite nano-particles are characterized by Fourier transform infrared spectroscopy (FT-IR), Powder X-ray diffraction (XRD) and Scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDAX), Hydrodynamic size and compressive strength. The tweaking results from the above various characterization techniques revealed the formation of well-resolved peak intensity with appealing microstructures and particle size distribution with better compressive strength values. On the basis of these observations, we envision that the iron oxide/silica core-shell magnetic nano-particles is an intersting biomaterial for orthopedical applications. © 2019 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of International Conference on Nanoscience and Nanotechnology (ICNAN'16)

Materials Today: Proceedings

Fabrication of Fe3O4-silica core-shell magnetic nano-particles and its characterization for biomedical applications

IET Nanobiotechnology

Development and characterisation of novel Ce-doped hydroxyapatite–Fe3O4 nanocomposites and their in vitro biological evaluations for biomedical applications

Multi-ion, co-substituted bioactive glass ceramics play a significant role in the stimulation of physical and biological properties for outstanding effects in biomedical application. The following work attempts to develop HAP as a parent material doped with a combination of cerium (Ce4+ @1.25 wt%) and silicon (Si4+ @1, 3 and 5 wt%) by refluxing based sol-gel technique. The anti-bacterial tests exhibit E. coli showing higher inhibition efficiency, in vitro hemolytic test exhibit good compatible nature of dual doped HAP with erythrocytes (&lt;5% of hemolytic). In vitro bioactivity assay confirms that the developed dual doped HAP possesses excellent bone-like apatite layer formation on their surfaces. In vitro cellular study was performed for Ce/Si-HAP@5% powder against MG-63 cells, which demonstrated the good cell viability at higher concentrations (up to 800 µg/ml). Further, dual doped HAP powders were characterized by various analytical techniques such as ATR-FTIR, Powder-XRD, TGA-DTA, SEM-EDS, TEM and XPS analysis. The studies confirm that the synthesized dual doped HAP will act as better bioactive glass ceramics for potential orthopedic and dentistry applications. © 2018 The Society of Powder Technology Japan

Advanced Powder Technology

Development of cerium and silicon co-doped hydroxyapatite nanopowder and its in vitro biological studies for bone regeneration applications

For the first time, in the present investigation, we have attempted the refluxing based sol-gel technique to synthesize cerium (Ce4 +) doped hydroxyapatite (Ce-HAP) with different concentrations such as 0.5, 0.75, 1 and 1.25%. The Ce-HAP powders were evaluated for in vitro biological studies such as hemocompatibility, antibacterial activity and biocompatibility. These in vitro studies have demonstrated the prominent results such as compatible nature with human blood (&lt; 5% hemolytic ratio) and excellent pathogen inhibition efficiency towards Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus) and Bacillus subtilis (B. subtilis) respectively. Among these, E. coli shows more susceptible towards 0.5–1.25% of Ce-HAP. In vitro biocompatibility study was performed on the 1.25% of Ce-HAP using MG-63 cells at various concentrations of 200–1000 μg/ml for 24–48 h. It was found that 1.25% of Ce-HAP powder was non-toxic up to the level of 600 μg/ml concentrations towards MG-63 cells with regular cell attachment and proliferation. The Ce-HAP materials were further characterized by UV–vis DRS spectroscopy, ATR-FTIR, Powder-XRD, SEM-EDAX, TEM, ICP-OES and XPS analysis. Therefore, this study proves that the developed Ce4 + doped HAP can be widely used in orthopedic and dentistry field with improved biological properties. © 2017 Elsevier Ltd

Materials & Design

Preparation and characterization of sol-gel derived Ce4+ doped hydroxyapatite and its in vitro biological evaluations for orthopedic applications

Hydroxyapatite [HAP] and tricalcium phosphate [ß-TCP] are a class of calcium phosphate related ceramic materials that are widely used in tissue regeneration and biomedical applications owing to their excellent bioactivity and biocompatibility. In this investigation, nanocrystalline pure HAP was prepared via sol-gel method by incorporating snail shell as calcium precursor with different phosphorus sources such as triethyl phosphate/phosphite (without using any additives like pH maintaining solutions or gelling agents). Nanocrystalline HAP and biphasic calcium phosphate (HAP + ß TCP) were prepared from triethyl phosphate and triethyl phosphite precursors, respectively. The prepared material was further characterized by powder XRD, IR, Raman spectroscopy, and thermo-gravimetrical analysis to confirm the phase purity, functional groups, and thermal stability. SEM coupled with EDAX was also used to examine the size, shape of particles, and elemental composition of Ca to P ratio in the material. Different phosphorus based HAP has shown rod and spherical shaped surface morphology which was further confirmed by TEM analysis. MTT assay was performed using NIH-3T3 fibroblast cell lines which indicated that the viability was not affected in various concentrations of pure nanocrystalline HAP (12.5-100 μg/ml). This study confirms the improved biocompatibility of biowaste converted HAP which would have implications in biomedical applications. Copyright © Taylor & Francis Group, LLC.

Materials and Manufacturing Processes

Snail Shell Derived Natural Hydroxyapatite: Effects on NIH-3T3 Cells for Orthopedic Applications

Salmonella typhi (S. typhi) is a facultative intracellular pathogen, causes typhoid fever in humans. Emergence of fluoroquinolones resistant strains is one of the major public health concern, reports revealed the occurrence of drug resistant strains with increasing minimum inhibitory concentration (MIC) of Ciprofloxacin have shown fatal effects and has led to treatment failures against S. typhi. The present study was focused on isolation of drug resistant S. typhi from various sewage samples. A totally four different drug resistant isolates were obtained on SSA plates supplemented with 200 μgL-1cefixime, a third generation drug used in the treatment of typhoid. The minimal inhibitory concentration was tested for the isolates and the isolate VITSSAJ3 was found to be resistant up to a concentration of 8000 μgL-1. © RJPT All right reserved.

Research Journal of Pharmacy and Technology

Isolation and characterization of drug resistantSalmonella typhifrom sewage water

Hydroxyapatite Ca 10(PO 4) 6(OH) 2 has attracted widespread interest from both orthopedic and dental fields due to its excellent biocompatibility and tissue bioactivity properties. Since nanophase materials can mimic the dimensions of constituent components of natural tissues, the implants developed from nanophase material could serve as a successful alternative. However, the defects of hydroxyapatite ceramics, mainly brittleness and low fracture toughness, have been overcome by the use of nanophase hydroxyapatite coatings on the implant surfaces that integrate the good mechanical properties of metals and the bioactivity of hydroxyapatite. In the present investigation, Sol-gel hydroxyapatite was prepared from two different phosphorus precursors such as triethyl phosphate and phosphorus pentoxide respectively with calcium nitrate tetrahydrate as a calcium precursor. The effects of pH and liquid P 31 Nuclear Magnetic Resonance spectroscopy for the solution aged at different periods were investigated and the synthesized hydroxyapatite powder was characterized by Transmission electron microscopy, X-ray Powder Diffraction, Fourier transform infrared spectroscopy and thermal analysis respectively. In order to fully understand the bioactivity of the synthesized materials, they were coated on 316L Stainless Steel implant surface by spin coating method at the spin speed of 2,000 Revolutions per minute. The effect of nanoparticles on the surface of 316L Stainless Steel implant was studied by adhesive strength measurements. The corrosion resistance property of the hydroxyapatite coatings was evaluated by electrochemical impedance analysis. From the results, it was observed that the hydroxyapatite coatings obtained from different precursors have very high resistance to corrosion with higher adhesive strength. © 2012 Springer Science+Business Media, LLC.

Journal of Sol-Gel Science and Technology

Influence of process parameters on the sol–gel synthesis of nano hydroxyapatite using various phosphorus precursors

Advanced Materials

Contents: (Adv. Mater. 21/2016)

ACS Biomaterials Science & Engineering

Is Nano-Silver Safe within Bioactive Hydroxyapatite Composites?

Preparation and characterization of novel Ag doped hydroxyapatite–Fe3O4–chitosan hybrid composites and in vitro biological evaluations for orthopaedic applications

Journal	Data powered by TypesetRSC Advances
Publisher	Data powered by TypesetRoyal Society of Chemistry (RSC)
ISSN	20462069
Open Access	No