Cell therapy has attained new heights with the current developments in the field of stem cell therapy and is often done in combination with gene therapy. Much research has gone into developing safe vectors to deliver genes to the cells used for cell therapy and also in tracking the transplanted cells and determining their fate. Even though viral vectors are very efficient in gene delivery, there are major safety concerns related to it. Herein, we report the use of novel fluorescent upconversion nanoparticles (UCNs) for simultaneous gene delivery and tracking of cells for cell-based therapies. It is a safe alternative to viral vectors and offers imaging capabilities too, which will give an insight on the fate of transplanted cells.

We describe an innovative and simple drop-cast processing strategy to create bonelike multicomponent bionanocomposite materials that consist of an organic poly(ε-caprolactone) (PCL) matrix, minerals such as hydroxyapatite (HAP) and CaCO3, and collagen fibers. The process allows morphological and structural control to achieve the desired nanostructure of the bone mimics. The fabrication method involves adding inorganic and organic components sequentially followed by controlling the growth conditions and composition. This enables organization of collagen nanofibers (∼ 100 nm) into scaffolds while simultaneously allowing nucleation and co-alignment of hydroxyapatite spheres (∼ 100 – 500 nm) within aligned, thermally stable collagen fibers in the porous PCL matrix. We achieved high calcium (26%) and oxygen (17%) within the bioscaffold and adequate phosphorous compositions comparable to the levels of bone tissues. Adequate mineralization along with high oxygen content may help maintain the required bone mineral density and revascularization for nutrient and compensate for the loss of oxygen delivered to the bone cells. Furthermore, since the bionanocomposite scaffold is made of natural materials (calcium, phosphorous and collagen) found in bone tissue, the formulation makes it an excellent biocompatible/biodegradable material. Our preliminary results suggest huge potential of these advanced bionanocomposite scaffolds for bone substitutes and tissue engineering applications.

In this work we demonstrate that the application of shear to a disordered lyoptropic liquid phase formed by a biological lipid, monoolein formed in water and butanediol results in the formation of an aligned lamellar phase. Furthermore we show that if shear is applied to this disordered phase in the presence of additional water, an highly oriented inverse bicontinous cubic phase is created. We suggest that these two phase may have applications as biological models, as templates for nanostructured materials and in improved protein crystallization techniques.

Luminescent lanthanide doped SiO2/Hydroxylapatite (HAp) core/shell nanoparticles (NPs) were synthesized by sol-gel technology. The resulting NPs exhibited an amorphous SiO2 core and a crystalline luminescent shell. The formation of the HAp layer was possible at pH 8.5. The characterization of the resulting NPs was done by transmission electron microscopy, X-ray diffraction analysis, inductively-coupled plasma combined with optical emission spectrometry, and photoluminescence spectroscopy. Additionally, the newly developed SiO2/HAp:Ln3+ core/shell NPs were tested for their biocompatibility, e. g. by an in vitro cell culture based assay.

Titanium possesses an excellent corrosion resistance in biological environments because the titanium dioxide formed on its surface is extremely stable. When aluminium and vanadium are added to titanium in small quantities, the alloy achieves considerably higher tensile properties than of pure titanium and this alloy is used in high stress-bearing situations. But these metals may also influence the chemostatic mechanisms that are involved in the attraction of biocells. V presence can be associated with potential cytotoxic effects and adverse tissue reactions. The alloys with aluminium and iron or with aluminium and niobium occur to be more suitable for implant applications: it possesses similar corrosion resistance and mechanical properties to those of titanium-aluminium-vanadium alloy; moreover, these alloys have no toxicity.

In this paper, pure Ti, Ti-6Al-7Nb and Ti-6Al-4Fe with a nanostructured surface were studied. Data about mechanical behavior are presented. The mechanical behavior was determined using optical metallography, tensile strength and Vickers microhardness.

For the electrochemical measurements a conventional three-electrode cell with a Pt grid as counter electrode and saturated calomel (SCE) as reference electrode was used. AC impedance data were obtained at open circuit potential using a PAR 263A potentiostat connected with a PAR 5210 lock-in amplifier. The ESEM and EDAX observation were carried out with an environmental scanning electronic microscope Fei XL30 ESEM with LaB6-cathode attached with an energy-dispersive electron probe X-ray analyzer (EDAX Sapphire). After 3 days of immersion in simulated body fluid the nucleation of the bone growth was observed on the implant surface.

It resulted that the tested oxide films presented passivation tendency and a very good stability and no form of local corrosion was detected. The mechanical data confirm the presence of an outer porous passive layer and an inner compact and protective passive layer. EIS confirms the mechanical results. The thicknesses of these layers were measured. SEM photographs of the surface and EDX profiles for the samples illustrate the appearance of a microporous layer made up of an alkaline titanate hydrogel. The apatite-forming ability of the metal is attributed to the amorphous sodium titanate that is formed on the metal during the surface treatment.

The results emphasized that the surface treatment increases the passive layer adhesion to the metal surface and improves the biocompatibility of the biomedical devices inducing the bone growth on the implant surface.

The present research discusses the thermal and structural properties of calcium alginate films synthesized by cross linking precursor sodium alginate films with Ca2+ ions. Raman and FTIR spectroscopy analyses evinced the interchange of Na ions with Ca ions. Both techniques revealed a shift of the COO- vibration modes; the symmetrical COO- peak of calcium alginate exhibited a shift towards higher wavenumber (∼14 cm−1) from 1415 cm−1 to 1429 cm−1 in the Raman spectra. TGA and TMA analyses performed under a nitrogen atmosphere revealed that increasing the Ca-molarity and immersion time resulted in an increase in the glass transition temperature (Tg) and the strain deformation of the Ca-alginate film. The increase in Tg can be attributed to the Ca-cross-linking that could restrict the molecular response to temperature change whereas the increased strain could be due to the enhanced entrapment of water between the molecular chains of the polymer.

Immobilization of oligonucleotide-functionalized magnetic nanobeads by hybridization in DNA-coils formed by rolling circle amplification has been investigated using transmission electron microscopy (TEM) and atomic force microscopy (AFM). The TEM results supported earlier made observations that small beads with low oligonucleotide surface coverage preferably immobilize in the interior of the DNA-coils and do not tend to link several DNA-coils together whereas large beads with high surface coverage to a larger extent connect several DNA-coils together to clusters of several DNA-coils with beads. AFM provided direct visualization of the DNA-coils as thread-like objects. DNA-coils with immobilized beads appeared as a collection of beads with thread-like features in their near vicinity.

Acid-etched dentin samples with a zone of demineralized dentin were remineralized via the polymer-induced liquid-precursor (PILP) process. Poly-L-aspartic acid was used as the polymeric process-directing agent. Samples were incubated in the mineralization solution for 1- 4 weeks. Dentin samples remineralized by the PILP process presented a surface morphology very similar to the intact mineralized dentin’s architecture, in contrast to samples mineralized via the conventional nucleation and growth method (without polymer additive), which led to a superficial crust of randomly organized mineral crystals. Energy dispersive x-ray spectroscopy analysis of the PILP-mineralized samples showed the presence of calcium and phosphate ions at high levels. Since no hydroxyapatite (HA) clusters were observed on the surface of the PILP-mineralized samples, we could conclude the signal was produced from the mineral embedded within the dentin matrix. TEM and diffraction analyses suggest that both intrafibrillar and interfibrillar remineralization occurred in the demineralized dentin matrix.

MnO nanoparticles (NPs) were surface functionalized by two different approaches, (1) using a dopamine-poly(ethylene glycol) (PEG) (DA-PEG) ligand and (2) by encapsulation within a thin silica shell applying a novel approach. Both MnO@DA-PEG and MnO@SiO2 NPs exhibited excellent long-term stability in physiological solutions. In addition, the cytotoxic potential of both materials was comparatively low. Furthermore, owing to the magnetic properties of MnO NPs, both MnO@DA-PEG and MnO@SiO2 lead to a shortening of the longitudinal relaxation time T1 in MRI. In comparison to the PEGylated MnO NPs, the presence of a thin silica shell led to a greater stability of the MnO core itself by preventing excessive Mn ion leaching into aqueous solution.

Metal oxide nanostructures have shown significant promise for biosensors, gas sensors, photocatalyst and other biomedical applications. Among these, zinc oxide (ZnO) nanostructures, exhibiting interesting properties such as high catalytic activity, biocompatibility, high isoelectric point, large surface to volume ratio, make them a good candidate for biosensing applications. Here we report the synthesis of ZnO nanorods (ZnONR) on ITO films in aqueous phase and its application in Urea biosensor fabrication. ZnONR have been synthesized by a two-step method, first seed growth of ZnO by sputtering on ITO films followed by decomposition of zinc nitrate hexahydrate / hexamethylenetetramine (HMT) in aqueous phase. Exploiting the high isoelectric point of ZnO, a Urease/ZnONR/ITO bioelectrode has been fabricated by physical binding of Urease (Urs) onto ZnONRs. X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and cyclic voltammetry (CV) have been used to characterize ZnONR and the Urs/ZnONR/ITO bioelectrode. The FE-SEM and XRD measurements confirm the formation of ZnONR. The electrochemical data from the Urs/ZnONR/ITO biolectrode reveal linearity between 1-11 mM with sensitivity of 0.9 μA/mM and a relatively low Michaelis-Menten constant (Km) of 5.01 mM for urea sensing. The results indicate the potential of ZnONR films for fabrication of commercial biosensors.

We propose the use of amine-rich polyelectrolyte multilayers as a versatile, high quality, tunable adhesive surfaces for biomedical and nanotechnological applications. The films are simple to fabricate under mild conditions and provide at least as good adhesion as standard aminopropyltriethoxysilane terminated glass substrates. In addition, the multilayer surface can be reliably passivated by acetylation with acetic anhydride which reduces the adhesion to the point that non-specific binding of proteins and nanoparticles becomes all but negligible. We demonstrate that this property, in combination with the robustness of the film, makes it possible to pattern the adhesiveness of the film at the nanoscale level.

The goal of this work is to understand the role of nano-confinement in designing an inexpensive and user friendly ‘point- of- care’ (POC) protein biosensor. We used printed circuit board based gold chips and integrated them with nanoporous alumina membranes in generating high density arrays of nano scale confined spaces. We initially tested the role of a nanomembrane in achieving signal enhancement through size based confinement of proteins. As a later part of the experiment, we studied the role of pore size on achieving signal enhancement by using membranes of two different pore sizes of 100 and 200 nm. It is critical that ultralow detection of biomolecules be achieved as they have significant impact in designing diagnostics platforms for early disease diagnosis. Commercially available nano-porous membranes made out of anodized alumina were evaluated for their role in nano-confinement and enhancing sensitivity of detection. In this biosensor configuration sandwich assay, an electrical double layer is formed between a test protein (C-reactive protein) and the gold surface underneath the porous membrane. Using electrical impedance spectroscopy, the capacitance/impedance changes in the electrical double layer, was analyzed which translated to identifying the sensitivity and the linear dose response of the sensor for two specific conditions (a) with nano confinement and (b) for varying size of confined spaces