Biomimetic patterning of polymer hydrogels with hydroxyapatite nanoparticles

We report here an in situ process to produce nano-composite polymer hydrogels having surfaces patterned with hydroxyapatite (HA) nanoparticles (100 nm). Poly (vinyl alcohol) (PVA) has been used as a hydrogel forming medium. A three step process, comprising precipitation of HA nanoparticles in presence of PVA molecules and freeze thawing of obtained PVA-HA emulsion, followed by critical point drying, has been devised to produce three dimensional nanocomposite hydrogels. Interaction of Ca2+ with oxygen atoms of PVA and the hydrogen bonding characteristic of the polymer have been exploited to have controlled size distribution of HA in a continuous and macroporous network of PVA. A systematic variation in the polymer concentration could be correlated with microstructural features of the hydrogel

Biomimetic synthesis of hybrid nanocomposite scaffolds by freeze-thawing and freeze-drying

The aim of this study is to biomimetically synthesize hydroxyapatite - hydrophilic polymer scaffolds for biomedical applications. This organic-inorganic hybrid has been structurally characterized and reveals a good microstructural control as seen by the SEM analysis and the nanosize of the particulates is confirmed by AFM microscopy. The characterization of such nano-structured composites would allow researchers to design new systems, tailoring properties for different applications. © Indian Academy of Sciences

EVALUATION OF TRACHYSPERMUM AMMI SEEDS FOR ANTIMICROBIAL ACTIVITY AND PHYTOCHEMICAL ANALYSIS

 Objective: The objective of this study is to identify medicinally important phytochemicals and evaluate the antimicrobial potential of Trachyspermum ammi seeds. Methods: Four different extracts (methanol, acetone, chloroform, and water) were prepared using a soxhlet apparatus, antimicrobial activity was tested using agar well-diffusion technique. Results: The results revealed the presence of flavonoids and saponins in all the extracts prepared. Similarly, alkaloids and phenols presence were obtained in methanol and aqueous extracts. Glycosides and carbohydrates in methanol, chloroform, and aqueous extracts. Further, proteins, terpenoids, and tannins presence were found in methanol, chloroform, and aqueous extracts, respectively. The maximum zone of inhibition was found in the methanolic extract (13.5 mm). Acetone, chloroform, and water extracts showed 9 mm, 10.5 mm, 11 mm respectively, while ciprofloxacin (control) showed 17.5 mm of the zone of inhibition. Conclusion: T. ammi seeds exert biological properties due to the presence of various chemical constituents. Thus, it can be used to obtain novel antibacterial compounds for the treatment of infectious diseases in the future

Waste utilization for the controlled synthesis of nanosized hydroxyapatite

This work uses biomolecules in waste and medicinally important materials for the synthesis of hydroxyapatite nanoparticles. Orange and potato peel, eggshell, papaya leaf and calendula flower extracts have varied biomolecules, which exert a significant, control on the in situ synthesis of nanosized hydroxyapatite particles. The biomimetic synthesis of inorganic particles using known matrices is already well established, however, there are only a few reports using compound extracts. The synthesized nanocomposite has been characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy studies. Role of varied biomolecules in controlled inorganic synthesis may have tremendous technological impact

Surface Mineralization of Hydrogels Through Octacalcium Phosphate

Simulated body fluid-induced nucleation and growth of octacalcium phosphate (OCP) on polyvinyl alcohol-hydroxyapatite (HA) hydrogels has been described and discussed in the present manuscript. Bulk mineralization of hydrogels is well reported in the literature for structural tissue engineering applications. However, a good interfacing between hydrogel scaffolds and biological organ, such as bone, could only be achieved through a suitable surface chemistry modification of the scaffold. OCP, a precursor to biological HA, may be an appropriate component of the hydrogel's surface likely to be used as a scaffold for bone tissue engineerin

A Novel Biomimetic Material-Glycine-PVA Ferrofluid That Crosses the Blood-Brain Barrier

The present study describes the efficacy of the glycine-poly(vinyl)alcohol ferrofluid as a contrast enhancer for Magnetic resonance imaging. Interaction between inorganic minerals and biomolecules are extremely unique and interesting. The results demonstrate that ferro fluids can be a good contrast enhancer for Magnetic Resonance Imaging as seen in the very first results after MRI studies

Low-Temperature Biomimetic Synthesis of beta-Tricalcium Phosphate by Altering pH

Biomimetic synthesis of beta-tricalcium phosphate (beta-TCP) in polyvinyl alcohol is done at a much lower temperature of 450 degrees C compared with conventional synthesis. By varying the pH of the reaction in a patented process for hydroxyapatite synthesis, the authors synthesized beta-TCP with controlled particle morphology at a very low temperature. The synthesized powder has been structurally characterized and cell studies with mesenchymal stem cells shows good adhesio

Microwave irradiation enhances kinetics of the biomimetic process of hydroxyapatite nanocomposites

In situ synthesized hydroxyapatite-poly(vinyl) alcohol nanocomposite was subjected to microwave irradiation, post synthesis. Interestingly, the aging time of 1 week required for the normal biomimetic process was reduced to 1 h post microwave irradiation, as characterized by x-ray powder diffraction and transmission electron microscopy. The surface topography shows the tendency of tubules to cross-link with the help of microwave energy. The microwave energy seems to provide a directional pull to the polymer chains which could have led to an enhancement of the kinetics of phase formation

Macroporous hybrid frameworks for bone graft substitute

Hybrid nanocomposite of poly(methyl methacrylate) reinforced with hydroxyapatite has been fabricated by phase separation mechanism of the polymer in the presence of a solvent having low solubility. The process demonstrates the formation of a three-dimensional honeycomb like macroporous structure of the hybrid material having struts patterned with micropores. Such mechanically stable open cell foam like structure has a potential to be used as a non-resorbable bone implant