We report herein a facile approach to synthesize processable bimetallic nanoparticles (Pd-Au/AuPd/Ag-Au/Au-Ag) decorated Prussian blue nanocomposite (PB-AgNP). The presence of cyclohexanone/formaldehyde facilitates the formation of functional bimetallic nanoparticles from 3-aminopropyltrimethoxysilane (3-APTMS) capped desired ratio of hetero noble metal ions. The use of 3-APTMS and cyclohexanone also enables the synthesis of polycrystalline Prussian blue nanoparticles (PBNPs). As synthesized PBNPs, Pd-Au/Au-Pd/Ag-Au/Au-Ag enable the formation of nano-structured composites displaying better catalytic activity than that recorded with natural enzyme. The nanomaterials have been characterized by Uv-Vis, FT-IR and Transmission Electron Microscopy (TEM) with following major findings: (1) 3-APTMS capped noble metal ions in the presence of suitable organic reducing agents i.e.; 3 glycidoxypropyltrimethoxysilane (GPTMS), cyclohexanone and formaldehyde; are converted into respective nanoparticles under ambient conditions, (2) the time course of synthesis and dispersibility of the nanoparticles are found as a function of organic reducing agents, (3) the use of formaldehyde and cyclohexanone in place of GPTMS with 3-APTMS outclasses the other two in imparting better stability of amphiphilic nanoparticles with reduced silanol content, (4) simultaneous synthesis of bimetallic nanoparticles under desired ratio of palladium/gold and silver/ gold cations are recorded, (5) the nanoparticles made from the use of 3-APTMS and cyclohexanone enable the formation of homogeneous nanocomposite with PBNP as peroxidase mimetic representing potential substitute of peroxidase enzyme. The peroxidase mimetic ability has been found to vary as a function of 3-APTMS concentration revealing the potential role of functional metal nanoparticles in bioanalytical applications.

While the quest for understanding and even mimicking biological tissue has propelled, over the last decades, more and more experimental activities at the micro and nanoscales, the appropriate evaluation and interpretation of respective test results has remained a formidable challenge. As a contribution to tackling this challenge, we here describe a new method for identifying, from nanoindentation, the elasticity of the undamaged extracellular bone matrix. The underlying premise is that the tested bovine bone sample is either initially damaged (i.e. exhibits micro-cracks a priori) or that such micro-cracks are actually induced by the nanoindentation process itself, or both. Then, (very many) indentations may relate to either an intact material phase (which is located sufficiently far away from micro-cracks), or to differently strongly damaged material phases. Corresponding elastic phase properties are identified from the statistical evaluation of the measured indentation moduli, through representation of their histogram as a weighted sum of Gaussian distribution functions. The resulting undamaged elastic modulus of bovine femoral extracellular bone matrix amounts to 31 GPa, a value agreeing strikingly well both with direct quasi-static modulus tests performed on SEM-FIB-produced micro-pillars (Luczynski et al., 2015), and with the predictions of a widely validated micromechanics model (Morin and Hellmich, 2014). Further confidence is gained through observing typical indentation imprints under Scanning Electron Microscopy (SEM), which actually confirms the existence of the two types of micro-cracks as described above.

Antiviral activity of metallic Ag nanoparticles immobilized on textile fabrics were investigated. The Ag nanoparticles synthesized by radiochemical process are firmly immobilized on the surface of support textile fabrics of cotton. Small Ag particles of about 2–4 nm were observed together with relatively large particles of more than 10 nm. The Ag nanoparticles showed antiviral activity against Influenza A and Feline Calicivirus. The antiviral activity significantly depended on the concentration of the Eagle’s minimal essential medium. It was implied that the surface passivation by inhibitory agent lead to the deactivation of metallic Ag nanoparticles.

Self-assembling peptides (SAPs) have the ability to spontaneously assemble into ordered nanostructures enabling the manufacture of ‘designer’ nanomaterials. The reversible molecular association of SAPs has been shown to offer great promise in therapeutics via for example, the design of biomimetic assemblies for hard tissue regeneration. This could be further exploited for novel nano/micro diagnostic tools. However, self-assembled peptide gels are often associated with inherent weak and transient mechanical properties. Their incorporation into polymeric matrices has been considered as a potential strategy to enhance their mechanical stability. This study focuses on the incorporation of an 11-residue peptide, P11-8 (peptide sequence: CH3CO-Gln-Gln-Arg-Phe-Orn-Trp-Orn-Phe-Glu-Gln-Gln-NH2) within a fibrous scaffold of poly (ε-caprolactone) (PCL). In this study an electrospinning technique was used to fabricate a biomimetic porous scaffold out of a solution of P11-8 and PCL which resulted in a biphasic structure composed of submicron fibers (diameter of 100-700 nm) and nanofibers (diameter of 10-100 nm). The internal morphology of the fabric and its micro-structure can be easily controlled by changing the peptide concentration. The secondary conformation of P11-8 was investigated in the as-spun fibers by ATR-FTIR spectroscopy and it is shown that peptide self-assembly into β-sheet tapes has taken place during fiber formation and the deposition of the fibrous web.

Understanding spatial and temporal neuronal activities is crucial for finding the cure for brain related ailments and advancement of our knowledge about the brain itself. This paper discusses our recent finding of the patternable rough textured gold microwire for neurochemical sensing. We have successfully fabricated the ∼5 µm wide and ∼ 60 nm thick gold microwires based electrochemical sensor. We produced these microwires along the edge of lithographically patterned nickel thin film. A nickel thin film edge was shadowed by the photoresist overhang during electrochemical growth only to allow gold deposition along the edges. Our electrochemical growth conditions yielded very rough textured sensor. Rough textured biosensors are highly desirable for increasing surface/volume ratio for efficient electrochemical sensing. These rough-textured microwires were transformed into the functional neurochemical sensor to detect dopamine. Our voltammetry and chronoamperometry studies on rough textured microwires based sensor confirmed the successful detection of dopamine.

A reverse micro-emulsion method has been investigated to control crystal morphology in a nanometer region and to increase specific surface area for calcium phosphate. The nanocrystals with the control of its morphology is a candidate of drug delivery carriers. This study investigated the effects of mixing volume ratios of two surfactants, tween80 (T) and aliquate 336 (A) in kerosene as an oil phase, and pH values in the nano-region on crystalline phases and specific surface area of calcium phosphate synthesized by the reverse micro-emulsion method. A di-ammonium hydrogen phosphate solution including phosphoric acid at pH of 6.3 and a calcium nitrate solution at pH of 5.7 were adjusted, and both the solutions were separately added into the kerosene with the surfactants. Both the emulsions were then mixed at the same volume and the Ca/P ratio of 1.0, and stirred at room temperature for 24 hours. The crystalline phases were dependent on the T amounts; pure DCPD with the specific surface area of 6.7 to 12 m2/g was obtained at the T/A ratio of 4, the mixture of DCPD and DCPA with that of 48 to 162 m2/g was at the ratios of 5 to 8, and a low crystalline HAp with 163 m2/g was at the ratio of 9. These specific surface areas of DCPD (T/A=4) and HAp (T/A=9) were apparently higher than those prepared with a wet method, 7.8 times and 1.8 times respectively. DCPA with 43 m2/g was successfully produced to decrease the pH of phosphate solution at T/A of 9. The change of crystalline phases would be explained as follows; the increase of T amount decreased the micro-emulsion sizes to reduce bulk water to be DCPA, and increased the pH to precipitate HAp nanocrystals.

The synthesis of gold nanoparticles (AuNPs) displaying pH and salt resistant activity has been a challenging tasks. The use of aminopropyltrimethoxysilane (3-APTMS) as one of the reagent during the synthesis of AuNPs may control such activity due to its micellar behavior. The AuNPs made from 3-APTMS capped gold ions in the presence of formaldehyde are found insensitive to pH- and salt. The major findings on 3-APTMS and formaldehyde mediated synthesis of AuNPs reveal the following: (1) 3-APTMS being amphiphilic, dispersibility of as prepared AuNPs largely depends on the organic reducing agents. (2) An increase in the hydrocarbon content of the reducing agent facilitate the dispersibility of AuNPs in organic solvent whereas decrease of the same increases the dispersibility in water, (3) AuNPs made through aldehydic reducing agents (formaldehyde and acetaldehyde) have relatively better salt and pH tolerance as compared to ketonic reducing agents (acetone, t-butyl dimethyl ketone), and (4) an increase in 3-APTMS concentrations enables salt- and pH- resistant property to AuNPs irrespective of organic reducing agents.

The biomedical applications of ZnO are drastically limited by its intrinsic solubility, which shortens the stability and lifetime of devices. We show that the functionality of ZnO in human mesenchymal stem cell (hMSC) studies is limited due to poor cell adhesion. The sol-gel route has been employed to obtain zinc titanate thin films for their integration as surface protective layer on ZnO. These films were obtained from zinc acetate (ZnAc) and titanium isopropoxide (TIPT). So derived xerogels were dried and their thermal evolution studied by TGM-DTA to identify critical annealing temperatures. The evolution of the microstructure and composition of spun cast films was determined by XRD and FTIR. Organic and ionic byproducts were eliminated at T>300°C, which kickstarts a transformation of the amorphous materials into polycrystalline. Thin films consisted of the ZnTiO3 perovskite from annealing temperatures of 500°C. Cell adhesion on the synthesized samples (both amorphous and crystalline) was assayed by culturing hMSCs. Immunofluorescence images of actin cytoskeleton were obtained and proliferation studied using Ki67. Cell density, single cell area and proliferation rates on ZnTiO3 films were closer to control TiO2 surfaces than to ZnO films. Such behavior validates the short term biocompatibility of ZnTiO3 films and its potential use as surface layer for ZnO biomedical devices.

Faster and more effective surface modification processes of polymer materials by UV/ozone treatment were investigated. The employment of ex-situ generated ozone and/or temperature control contributed to the faster and more effective modification. The UV/ozone treatment showed long-term stable hydrophilic surfaces for 6 months, in contrast to oxygen plasma treatment, which showed hydrophobic recovery. XPS analysis revealed that UV/ozone treatment with ex-situ generated ozone and temperature control added ester (-COOR) on COP sample compared to UV/ozone treatment without the additional ozone and temperature control.

In the field of tissue engineering, design and fabrication of precisely and spatially patterned, highly porous scaffolds/matrixes are required to guide overall shape of tissue growth and replacement. Although rapid prototyping fabrication techniques have been used to fabricate the scaffolds with desired design characteristics, controlling the interior architecture of the scaffolds has been a challenge due to Computer-aided Design (CAD) constrains. Moreover, thick engineered tissue scaffolds show inadequate success due to the limited diffusion of oxygen and nutrients to the interior part of the scaffolds. These limitations lead to improper tissue regeneration. In this work, in order to overcome these design and fabrication limitations, research has been expanded to generation of scaffolds which have inbuilt micro and nanoscale fluidic channels. Branching channels serve as material delivery paths to provide oxygen and nutrients for the cells. These channels are designed and controlled with Lindenmayer Systems (L-Systems) which is an influential way to create the complex branching networks by rewriting process. In this research, through the computational modeling process, to control the thickness, length, number and the position of the channels/branches, main attributes of L-Systems algorithms are characterized and effects of algorithm parameters are investigated. After the L-System based branching design is completed, 3D tissue scaffolds were fabricated by “UV-Maskless Photolithography”. In this fabrication technique, Polyethylene (glycol) Diacrylate (PEGDA), which is biodegradable and biocompatible polymer, was used as a fabrication material. Our results show that L-System parameters can be successfully controlled to design of 3D tissue engineered scaffolds. Our fabrication results also show that L-System based designed scaffolds with internal branch structures can be fabricated layer-by-layer fashion by Maskless Photolithography. This technology can be easily applied to engineering living systems.

In the present study, highly sensitive and high-throughput optical waveguide biosensors were fabricated by using the sensing membranes containing dye and polymer-enzyme complex. Optical light waveguide can detect the optical change in the vicinity of the guide surface with high sensitivity due to the evanescent wave scattering. The glucose sensing membranes, composed of dye, enzymes, and biocompatible polymers were prepared by solution processing on the optical waveguide. Herein, we used 3, 3’, 5, 5’-tetramethylbenzidine (TMBZ) as a dye, glucose oxidase (GOD) and peroxidase (POD) as enzymes, phosphatide polymer for protection of biological activity of enzyme, and carboxymethyl cellulose (CMC) as a binder. Then we focused on the optimal composition and structure of sensing membranes for the enhancement in the sensitivity and response speed. The developed glucose sensors demonstrated 20 times higher sensitivity than the conventional light waveguide glucose sensors and the low-detection limit of 0.1g/L glucose within the detection time of 60 sec. For further improvement in the sensitivity, microporous sensing membranes were fabricated by using electrospraying technique. The electroprayed sensing membranes gave 40 % higher sensitivity than nonporous sensing membranes. These results show that both the composition and structure of sensing membrane are crucial factors for highly sensitive and high-throughput optical waveguide biosensors.