Magnetic responsive particles were designed for use in oral delivery of insulin. Magnetite nanoparticles (12 nm average size) were synthesized and co-encapsulated with insulin into poly(lactide-co-glycolide) (PLGA) microparticles (4.6 ± 2.2 μm average particle size) through the double-emulsion method. The spherical structures of resulting microparticles were well maintained at magnetite content 5 wt % or less. Mice were gavaged with 125I-insulin-magnetitePLGA microparticles and a circumferential trans-abdominal magnetic field was applied forty minutes after administration to retard the transit of the microparticles in the intestinal tract. As control, mice were similarly dosed without the subsequent trans-abdominal magnetic field. Mice were sacrificed, and the intestinal radioactivity was 101% and 145% higher in treated mice versus the control at 6 h and 12 h, respectively. A single administration of 50 unit/kg Humulin Rmagnetite-PLGA microparticles to the fasted mice resulted in 66% reduction of blood glucose level in the presence of external magnetic field at 12 h, compared to 27% reduction in the absence of magnetic field.

Nanohybrid artificial membranes made by intercalation of amphiphilic molecules into the galleries of a layered host, exhibit characteristics similar to biological membranes and they can be used as sensors. Different responses have been observed even for molecules that have similar features for example, saccharin and its sodium salt suggesting that the nanohybrid might be useful in developing an electronic nose. The dynamic range of the saccharin sensor is 20 - 300μM. In this paper we present our results on sensor fabrication and testing and discuss possible sensing mechanisms. In addition, we describe our work on immobilizing in the nanohybrid membranes Glucose Oxidase, Horseradish Peroxidase and Gramicidin and evaluating their performance.

Electroporation/electropermeabilization is a non-viral technique for gene transfection and drug delivery. Here, the transfer mechanisms were studied with fluorescent nanocrystals (quantum dots, QDs) in mammalian cells. Interactions of the cell membrane and nanoscale particles were visualized after electric pulse treatment. Responses of human multiple myeloma cells to nanocrystals were tracked for periods up to 7 days. Large particles do not cross the membrane directly after pulsing, even if the membrane is permeabilized to small molecules. Large QDs were trapped on the cell membrane for hours after electroporation and were gradually either excluded or internalized by cells. QD uptake efficiency depended on both particle size and membrane transport activity. These results, consistent with an electropermeabilization model, suggest that enhancing the interactions between the cell membrane and macromolecules may improve the transfer efficiency.

In the past decade, tissue engineering has become a great interest in materials science research. Embryonic stem (ES) cell transplantation has become one of the most researched therapies for restoring tissue and organ function. Many studies have investigated the use of porous biodegradable scaffolds to promote cell adhesion, growth, proliferation, differentiation, and to help steer the course of tissue development. Research has shown that extracellular matrices and the basement membranes affect various cell types and cellular behaviors. However, the effects of these materials on ES cell behavior are currently understudied and poorly understood.

In this study, the synthetic biodegradable polymer polycaprolactone (PCL) was chosen to create an interconnected, fibrous foam structure. A phase separated scaffold method was developed and the product made was coated with various extracellular materials. When the phase separated PCL scaffolds were coated with Matrigel and gelatin solutions, murine ES (mES) cells attached, spread, and differentiated within the scaffolds. There was little growth on the uncoated material. Coating effects on mES cells were analyzed using flow cytometry, reverse-transcriptase polymerase chain reaction and scanning electron microscopy. It was found that coating the scaffold with different extracellular matrices affects mES cell morphology and differentiation. Matrigel coating causes expression of neural proteins and gelatin produces a hepatocyte-like cell.

We specially designed a slow chemical reaction system to synthesize the zinc selenide nanoparticles (ZnSe NPs), in the cavity of the cage-shaped protein, apoferritin. The newly designed chemical synthesis system for ZnSe NPs makes the chemical reaction of compound semiconductor element ions dramatically slow, resulting in that ZnSe NPs can be synthesized in the internal cavity of the apoferritin. The ZnSe NPs synthesized by the optimized reaction parameters are efficiently produced in the aqueous solution. The UVVis spectrum analysis of synthesized ZnSe-ferritin suggests that the formation of ZnSe nuclei in the apoferritin cavity takes about 6 hours by using our slow chemical reaction system. The synthesized ZnSe NPs were characterized by high resolution TEM, X-ray powder diffraction (XRD) and Energy Dispersive Spectrometory (EDS) and it was revealed that the synthesized NPs are a collection of cubic ZnSe crystals.

Titanium implants have been used for decades with success in various applications. The characteristics of titanium that allows acceptance in the body are not well defined. It is known that hydrogen peroxide is a chemical species produced during the inflammatory response following implantation. When titanium is exposed to hydrogen peroxide, a Ti-peroxy gel (TiOOH) is formed. Three possible functions of Ti-peroxy gel are: reduction of the inflammatory response through the reduction of hydrogen peroxide and other reactive oxygen species; creation of a favorable surface for calcium phosphate nucleation; and as a transitional layer between the soft tissue and the stiff titanium. These studies utilized atomic force microscopy (AFM) force spectroscopy, electrochemical techniques, Raman spectroscopy, and optical transparency in situ to define kinetic and mechanical properties of Ti-peroxy gel as it forms on titanium during exposure to hydrogen peroxide. Peaks attributed to Ti-peroxy gel were seen to emerge over the course of several hours using in situ Raman spectroscopy. Force-distance curves suggest a layer that thickens with time on the titanium sample surface.

In2O3 nanoparticles were fabricated in the cavity of the cage-shaped protein, apoferritin by utilizing a quick chemical reaction of indium oxide. Horse spleen apoferritin in the solution of indium ions buffered at pH 9.5 was incubated for 30 minutes. The transmission electron microscopy (TEM) observation with aurothioglucose staining showed that cores were formed in the apoferritin cavity. The sizes of cores were regulated by the cavity size and their diameters were below 7nm. Energy dispersion X-ray analysis (EDX) indicated that indium was contained in the cores. The high-resolution TEM (HR-TEM) revealed that cores are single or poly crystalline and the lattice space was consistent with that of In2O3. These results confirmed that the In2O3 cores were successfully formed in the apoferritin cavity.

The biology and semiconductor technology have progressed independently. There was a large distance between them and a substantial interdisciplinary research area was left untouched. Recently, this situation is gradually changing. Some researchers are stimulating semiconductor technology by introducing bio-molecules into the nano-fabrication process. We proposed a new process for fabricating functional nano-structure on a solid surface using protein supramolecules, which we named “Bio Nano Process” (BNP). We employed a cage-shaped protein, apoferritin and synthesized several kinds of nanoparticles (NP) in the apoferritin cavity. A two-dimensional array of them was made on the silicon wafer and this array was heat treated or UV/ozone treated. These processes produced a two-dimensional inorganic NP array on the silicon surface. The size of the NP is small enough to be used as quantum dot and the floating nanodots memory using this NP array is now under development. We also proposed another application of the BNP, making use of the obtained nanodot array as the nanometric etching mask. This was realized by employing the neutral beam etching and 7nm Si nano columns with high aspect ratio were fabricated. These experimental results demonstrate that the BNP can fabricate the inorganic nanostructure using protein supramolecules and the BNP opened up a biological path to nanoelectronics devices.