Review Article: Immobilized Molecules Using Biomaterials and Nanobiotechnology

Immobilized molecules using biomaterials and nanobiotechnology is a very interesting topic that touching almost all aspects of our life. It uses the sciences of biology, chemistry, physics, materials engineering and computer science to develop instruments and products that are at the cutting edge of some of today’s most promising scientific frontiers. In this review article, the author based on his experience in this arena has tried to focus on some of the supports for im-mobilization;the most important molecules to be immobilized such as DNA, cells, enzymes, metals, polysaccharides, etc and their applications in medicine, food, drug, water treatment, energy and even in aerospace. He specified a special section on what is new in the arena of supports and technologies used in enzyme immobilization and finally a recommendation by the author for future work with a special attention to up-to-date references.

Osteogenesis of MC3T3 Preosteoblasts on 3D Bioactive Peptide Modified Nano-Macroporous Bioactive Glass Scaffolds

Biointerface design that targets osteogenesis is a growing area of research with significant implications in biomedicine. Materials known to either support or stimulate osteogenesis are composed of a biomimetic ceramic material, such as bioactive glass. Bioactive glass is osteoproductive, and the potential for osteoproductivity can be enhanced by the addition of proteins or other additives designed to alter functionality. In addition, soluble growth factors are often added to osteogenic culture on bioactive glasses, further intensifying the effects of the material. In this paper, synthetic peptide combinations, covalently bound to a three-dimensional bioactive glass network, are used to mimic the effects of the whole fibronectin and bone morphogenetic proteins (BMP) 2 and 9. Peptide-silanes possessing critical binding sequences from each of these proteins are synthesized and used to decorate the surface of three-dimensional (3D) nano-macroporous bioactive glass. MC3T3 preosteoblast cells are then assessed for differentiation on the materials in the absence of soluble differentiation cues. MC3T3 preosteoblasts undergo enhanced differentiation on the peptide-silane samples over the standard nano-macroporous bioactive glass, and the differentiation capacity of the cells exposes only to peptide-silane surfaces approaches that of cells grown in chemical differentiation induction media.

Equivalent circuit method for static and dynamic analysis of magnetoelectric laminated composites

Magnetoelectric equivalent circuit analytical method is presented for laminate composites of magneto- strictive Terfenol-D (TbxDy1-xFe2) and piezoelectric Pb(Zr1-xTix)O3 (PZT) operated in longitudinal mag- netized and transverse polarized (or L-T), and transverse magnetized and transverse polarized (or T-T) modes. Magnetoelectric (ME) couplings both at low-frequency and resonance-frequency have been studied, and our analysis predicts that (i) the ME voltage coefficients of both L-T and T-T modes in- crease with increasing the thickness of the piezoelectric phase whereas magnetostrictive phase thickness keeps constant, and then tend to saturation when the thickness ratio of piezoelectric phase to magnetic phases is >3; (ii) there are the optimum thickness ratios that maximize magnetoelectric (ME) voltage coefficients for the two modes, which are dependent on elastic compliances ratio of piezoelec- tric phase and magnetostrictive phase; and (iii) the ME voltage coefficients are dramatically increased by a factor of ~Qm, when operated at resonance frequency. A series of Terfenol-D/PZT laminates were fabricated, and the results were compared with the theoretical ones. Experiments confirmed that equivalent circuit method is a useful tool for optimum designs of ME laminates.

Two-color spectroscopy of UV excited ssDNA complex with a single-wall nanotube photoluminescence probe： Fast relaxation by nucleobase autoionization mechanism

DNA autoionization is a fundamental process wherein ultraviolet （UV）- photoexcited nucleobases dissipate energy by charge transfer to the environment without undergoing chemical damage. Here, single-wall carbon nanotubes （SWNT） are explored as a photoluminescent reporter for the study of the mechanism and rates of DNA autoionization. Two-color photoluminescence spectroscopy allows separate photoexcitation of the DNA and the SWNTs in the UV and visible range, respectively. A strong SWNT photoluminescence quenching is observed when the UV pump is resonant with the DNA absorption, consistent with charge transfer from the excited states of the DNA to the SWNT. Semiempirical calculations of the DNA-SWNT electronic structure, combined with a Green＇s function theory for charge transfer, show a 20 fs autoionization rate, dominated by hole transfer. Rate-equation analysis of the spectroscopy data confirms that the quenching rate is limited by thermalization of the free charge carriers transferred to the nanotube reservoir. This approach has great potential for monitoring DNA excitation, autoionization, and chemical damage, both in vivo and in vitro.

Facet-dependent Cu2O nanocrystals in manipulating alignment of liquid crystals and photomechanical behaviors

Manipulating the alignment of liquid crystals (LCs) is a hot and fundamental issue for their applications in block copolymers, photonics, actuators, biosensors, and liquid-crystal displays. Here, the surface characteristic of Cu2O nanocrystals was well controlled to manipulate the orientation of the LCs. The mechanism of the orientation of the LCs induced by Cu2O nanocrystals was elucidated based on the interaction between the LCs and Cu2O nanocrystals. To comprehensively prove our assumption, different types of LCs (nematic, cholesteric, and smectic) as well as the same type of LCs with different polarities were selected in our system. Moreover, the photomechanical behaviors of the LC polymer composites demonstrated that the alignment of LCs can be effectively manipulated using Cu2O nanocrystals. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.