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Advanced Nano-Bio-Materials and Devices – AdvNanoBioMD 2019; Vol 3; Issue 4 is now released. Thank you for all the contributors and reviewers!

Advanced Nano-Bio-Materals and Devices – AdvNanoBioMD 2019; Vol 3; Issue 4 (December 30)

The novel properties of nanomaterials also encourage their use to improve the growth of different tissues. Nano structured ceramics can be synthesized; thus, they may have particle size, geometry and microarchitecture similar to physiological bone. In this study, mechanical and bioactivity properties of nanohydroxyapatite (nHA)-nano magnesium oxide (nMgO) and nano hydroxyapatite (nHA) -nano niobium (V) oxide (nNb2O5) composites were compared. 80 wt.% nHA-20 wt.% MgO (nMH1), 70 wt.% nHA-30 wt.% MgO (nMH2), 80 wt.% nHA-20 wt.% Nb2O5 (nNH1) and 70 wt.% nHA-30 wt.% Nb2O5 (nNH2) nano composites including non-toxic binder were shaped by using press. The composites were sintered at 1000 and 1100°C for 2 hours, then microstructures, mechanical and bioactivity properties were determined. The physical and mechanical properties were determined by measuring density, firing shrinkage, compression strength and Vickers microhardness (HV). Structural characterization was carried out with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The bioactivity properties were determined after soaking the samples in the simulated body fluid. Density, compression strength and Vickers microhardness values of composites increased with increasing sintering temperature. The best density, compression strength and Vickers microhardness values were obtained with 70 wt.% nHA-30 wt.% MgO (nMH2) composite sintered at 1100°C as 3,16 g/cm3, 135 MPa and 438 HV, respectively.

In this work, we have investigated the self-assembled monolayer (SAM) of L-cysteine on Au(111) and its application in electrochemical oxidation of uric acid by scanning tunneling microscopy (STM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Monolayer of L-cysteine on Au(111) was observed, which shows that single monolayer of L-cysteine was formed on Au(111). Oxidation peak at 0.47 V was found for uric acid in 0.1 M HAc-NaAc buffer solution containing 2×10-5 M uric acid with pH=4.6 by CV, while two peaks can be observed for the solution with additional molecule of ascorbic acid. The influence of pH on electrochemical behavior of uric acid and ascorbic acid was also performed, which found that the peak distance and current is larger for pH=4.6 than that for pH=6. Those show that the solution with pH=4.6 may be good for the simultaneous detection of uric acid and ascorbic acid.

Nanometric particles and crystals play very important roles in biological systems. For example, calcium orthophosphates (abbreviated as CaPO4) of nanometric dimensions represent the basic inorganic building blocks of bones and teeth of mammals. According to recent discoveries in biomineralization, zillions nanometric crystals of biologically formed CaPO4 are nucleated in body fluids and, afterwards, they are self-assembled into these complex structures. In addition, both a greater viability and a better proliferation of various types of cells have been detected on smaller crystals of CaPO4. All these effects are due to a higher surface-to-volume ratio, an increased reactivity and biomimetic morphologies of the nanometric particles. Thus, the nanometric and nanocrystalline forms of CaPO4 appear to be natural for living organisms and, thus, they have a great potential to revolutionize the hard tissue-engineering field, starting from bone repair and augmentation to controlled drug delivery systems. Therefore, preparation and applications of nanometric CaPO4 are the important topics in modern biomaterial science and such formulations have been already tested clinically for various purposes. Currently, more efforts are focused on the possibility of combining nanometric CaPO4 with cells, drugs and/or other biologically active substances for multipurpose applications. This review describes current state of the art and recent developments on the subject, starting from synthesis and characterization to biomedical and clinical applications.