Histidine-rich proteins (HRP), which function in the biological control of inorganic materials, have been identified in the liver fluke Fasciola hepatica, marine polychaetes, humans, and the malarial parasite Plasmodium falciparum. For example, the malarial parasite contains HRP II composed of repeating peptide sequences of Ala-His-His-Ala-His-His-AlaAla-Asp. This peptide was screened as a stabilizing peptide coat for a variety of nanoclusters of Ag0, Au0, ZnS, TiO2, and Ag2S, and characterized by UV-Vis spectroscopy, fluorescence, IR, XRD, and TEM. The resulting nanoclusters were examined for immunoreactivity against a commercial monoclonal antibody for HRP II of P. falciparum.

One of the primary challenges for engineering thick, complex tissues such as vital organs is the requirement for a vascular supply for nutrient and metabolite transfer. Earlier work has shown that Solid Freeform Fabrication techniques such as Three-Dimensional Printing (3DP) are capable of producing biodegradable scaffolds for the subsequent formation of a wide range of tissues and organs. While this approach shows great promise as a method for constructing complex tissues and organs in vitro, the resolution of the process is currently limited to length scales larger than the narrowest capillaries in the microcirculation. In this work, microfabrication technology is demonstrated as an approach for organizing endothelial cells in vitro at the size scale of the microcirculation. Standard process techniques utilized to build MEMS (MicroElectroMechanical Systems) devices include photolithography, silicon and glass micromachining, and polymer replica molding. Photolithography is used to print a model network of blood vessels on silicon wafers; the network is designed to replicate the fluid dynamics of the vasculature of a particular tissue or organ. A reverse image of the channel network is formed either by Deep Reactive Ion Etching (DRIE) of silicon or through the use of a thick negative-polarity photoresist (SU-8). Polymeric scaffolds are formed by replica molding, using the silicon wafer as a master mold. Microfluidic chambers have been constructed from PDMS and other biocompatible polymers. Initial cell seeding experiments demonstrate that rat lung endothelial cells attach in a single layer to the walls of these structures without occluding them, providing early evidence that MEMS process technology can serve as a method for organizing capillary networks.

Diacetylenic phospholipids with disulfide functionality were synthesized and incorporated at dopant levels with unmodified diacetylenic phosphatidylcholine lipids in polymerized vesicles. These polymerized vesicles were immobilized on Au films and structurally characterized in situ using AFM and ESEM and demonstrated surface stability of at least three days. Polymerized diacetylenic phospholipid vesicles displayed retention of entrapped ferricyanide with a half-life of 2.4 weeks at pH 7 and 25 oC. Membrane-bound benzoquinone mediated electron transport across polymerized vesicle membranes providing an initial current of 25 mA and a final charge capacity based on entrapped ferricyanide of 3.5 Ahr/kg. Electron transport across polymerized diacetylenic phospholipid vesicle membranes was described by a pseudosteady-state transport model and was found to be diffusion limited.

A Quartz Crystal Microbalance (QCM) was used to create a biosensor utilizing living adherent endothelial cells (ECs) as the biological sensing element. This EC QCM biosensor detected the effect of varying concentrations of nocodazole, a microtubule binding and disrupting drug, on the adherent cells as they altered the underlying QCM device state frequency, Δf, and motional Resistance, ΔR, shift values. Over the dose range 0.11-15 μM nocodazole, the Δf shift values decreased significantly in magnitude in a dose dependent fashion over a 5-6 hr incubation period following drug addition to a limiting value, with a 900 nM midpoint. This effect is consistent with nocodazole's known dose dependent effect on the disruption of microtubules. At all drug concentrations, the relative Δf decrease with time was found to be very similar and well fit by a single exponential decay equation. For all nocodazole doses, t 0.5 was invariant, averaging t 0.5 = 0.83 ± 0.14 hr. These data demonstrate that a single dynamic sensing system within the cell, the microtubules, responds to the addition of nocodazole and its response can be quantified by the biosensor. These results indicate that the EC QCM biosensor can be used to detect EC cytoskeletal alterations and dynamics and may be a valuable screening method for all classes of biologically active drugs or biological macromolecules that affect cytoskeleton perturbations or cellular attachment.

The inner porous part of the PTFE [poly-tetrafluoroethylene] membrane was substituted with a hydrophilic group using irradiation by an ArF laser. Water was employed for a defluorination agent in order to inhibit rejection. The membrane was developed that automatically pumps out water when the pressure is raised above a fixed value. The increased intraocular pressure with aqueous outflow failure causes glaucoma. In healthy humans intraocular pressure is maintained at a normal physiological level of between 8 to 18 mmHg. When the pressure exceeds 21 mmHg, a diagnostic of glaucoma may be predicted.

We designed a new type of membrane to pump the aqueous humor and regulate its outflow. The membrane has gained characteristics of aqueous humor penetration by substituting a part of a hydrophobic group that exists inside the porous PTFE with the hydrophilic group. Furthermore our previous studies have found that B, Al and H atoms are effective for defluorination of atoms from fluorocarbon. In this study three kinds of reaction liquid containing B, Al and H respectively were used. By this defluorination reaction B and Al atoms were better than H atoms. We prepared a boric acid water solution (B(OH)3), nitro aluminate water solution (Al(NO3)3) and water (H2O) as chemical compounds for defluorination and OH substitution. When ethyl alcohol is dropped on the porous PTFE, it penetrates into inner porous PTFE easily. When the three kinds of chemical compound water solutions are dropped onto the porous PTFE membrane, the solution is trapped up to the inner side of porous PTFE. When each sample with hydrophilic property treatment was implanted into rabbits' eyes and its biocompatibility was tested, some samples using Al and B atoms for defluorination have shown the rejection reaction called neoplasm blood vessel. However, the other samples using water as the reaction liquid have shown no rejection.

Endovascular stents can be altered to improve radioopacity by applying a gold coating. We examined the vascular response in porcine coronary arteries to implantation of 9 mm NIR® stents that were either left intact, gold-coated, or heat-treated following gold coating. Our results show that while gold coating exacerbates neointimal hyperplasia and the inflammatory response, heat treatment removes this negative effect. Heat treatment was shown to increase the diffusion at the gold-steel interface and reduce the surface roughness.

We have used one- and two-particle microrheology, employing μm-sized beads and laser interferometric displacement detection, to study the rheological properties of entangled solutions of the filamentous fd virus. Thermal fluctuations of the embedded probes were measured and viscoelastic parameters of the embedding medium were derived. In two-particle microrheology the correlated motions of two identical particles separated by a varying distance in the medium are analyzed, which can avoid biased results due to surface-depletion effects near the probes.

In this work, the surface properties of a DNA microarray formed on silicon based solid support are studied at different stages during the hybridization process. A modified immobilization process using the covalent immobilization of thiol-terminated DNA oligonucleotides on self-assembled layers of (3-mercaptopropyl) trimethoxysilane (MPTS) by disulfide bond formation is used to selectively attach DNA probes onto the surface of silicon dioxide. Contact angle measurement is used to monitor the bonding of MPTS on the surface. Atomic force microscopy (AFM) shows an increase in particle size before and after the growth of the MPTS layer. Fluorescence microscopy reveals the success of hybridization of complementary oligonucleotides labeled by FAM to the probe. The effects of modified immobilization process on other common material in silicon processing are also studied. As a result of the corrosive chemical used in the process, common metals used in micro-fabrication processes like aluminum are etched away. Silicon nitride is not affected by the immobilization and hybridization process, and thus can be used as a passivation and isolation material to conform the DNA to a specific area for DNA microarray to reduce cross-talk. The fluorescence image from the scanner indicates silicon nitride can effectively be used as an isolation material with linewidth down to 1 μm.

Accumulation of metals in inorganic granules is very common in invertebrates. The formation of metal deposits in both intra- and extracellular sites can be seen as a process for the detoxification of heavy metals. In barnacles, such inorganic granules usually contain calcium pyrophosphate. Incorporation of metals within such granules occurs mainly via the formation of metal pyrophosphate salts. In order to assess the chemistry of some reactions occurring during granule formation, the synthesis of calcium pyrophosphate, doped with zinc(II) ions with different [Zn]:[Ca] molar ratios, has been investigated at pH 7 and 25 °C. The thermal stability of the products was studied at different temperatures. Considerable variations occur in the structure of calcium pyrophosphate when zinc ions are present in solution in small concentrations.

One of the most common methods for obtaining water repellent surfaces is spreading fluoropolymer or fluoroalkylsilane onto substrates. However, this method is not applicable to low heat-resistant substrates such as plastics, since after spreading, the method requires a heating process which is generally conducted at a temperature of about 600K. The objective of this study is the preparation of ultra water-repellent and optically transparent thin films at low temperatures below 373K. The films were deposited by means of microwave plasma enhanced plasma chemical vapor deposition (MPECVD) using organosilane, that is, trimethylmethoxysilane (TMMOS) as a source with adding Ar, CO2, N2, O2 or air as an excitation gas. Under optimized preparation conditions, films with water contact angles more than 150 degrees and optical transparencies more than 90% were successfully fabricated.

Artificial cartilage can be grown from cultured chondrocytes, but adhering this tissue to bone presents a challenge. Porous polymer/bioactive glass composites are candidate materials for engineering the artificial cartilage/bone interface and possibly other soft-to-hard tissue (ligament/bone, tendon/bone) interfaces. A phase separation technique was used to make porous polymer/bioactive glass composites. The composites (thickness: 200-500 μm) have asymmetric structures with dense top layers and porous structures beneath. The porous structures consist of large pores (>100 μm) in a network of smaller (<10 μm) interconnected pores. The dense layers were removed and large pores exposed by abrasion or salt leaching from the casting surface. The tissue bonding abilities of the composites were studied in vitro in simulated body fluid (SBF) and in rabbit chondrocyte culture. Culture studies revealed that composite surfaces were suitable for attachment, spreading and proliferation of chondrocytes. The growth of hydroxycarbonate apatite (HCA) inside and on the composites after soaking in the SBF for two weeks demonstrates their potential for integration with bone. The results indicate the potential for the composites to facilitate growth and attachment of artificial cartilage to bone.

In recent years, the extraordinary properties of bio-inspired nanocomposites have stimulated great interest in the development of bottom-up synthetic approaches to organic-inorganic hybrid materials in which molecular scale control is exerted over the interface between the organic and inorganic moieties. These developments have led to advanced materials with novel properties and potential use in catalysis, sensing, separations and environmental remediation. Periodic mesoporous organosilica (PMO) materials are an entirely new class of nanocomposites with molecularly integrated organic/inorganic networks, high surface areas and pore volumes, and well ordered and uniform size pores and channels. We recently have extended the approach to include novel PMO materials incorporating chiral and heteroatom-containing organic functional groups inside the inorganic framework that may be useful in asymmetric catalysis, enantiomeric separations and heavy metal remediation.

Biomaterials that successfully integrate into surrounding tissue should match not only the tissue's mechanical properties, but also the dimensions of the associated nano-structured extra-cellular matrix (ECM) components. The goal of this research was to use these ideals to develop a synthetic, nano-structured, polymeric biomaterial that has cytocompatible and mechanical behaviors similar to that of natural vascular tissue. In a novel manner, poly-lactic acid/polyglycolic acid (PLGA) (50/50 wt.% mix) and polyurethane were separately synthesized to possess a range of fiber dimensions in the micron and nanometer regime. Preliminary results indicated that decreasing fiber diameter on both PLGA and PU enhanced arterial smooth muscle cell adhesion; specifically, arterial smooth muscle cell adhesion increased 23% when PLGA fiber dimensions decreased from 500 to 50 nm and increased 76% on nano-structured, compared to conventional structured, polyurethane. However, nano-structured PLGA decreased endothelial cell adhesion by 52%, whereas adhesion of these same cells was increased by 50% on polyurethane. For these reasons, the present in vitro study provides the first evidence that polymer fiber dimensions can be used to selectively control cell functions for vascular prosthesis.

The melting of the semicrystalline poly(ethylene oxide)(PEO)/ poly(ε -caprolactone) (PCL) multiblock copolymer was investigated by small and wide angle x-ray scattering. The two-stage melting was found in which the PEO block and the PCL block melt independently. The crystalline PEO Bragg peaks disappear at 30.5 °C while the block spacing increases due to the chain relaxation. The PEO crystalline domain size decreases continuously in proportion to the amount of the crystalline part. Above 40 °C, the PCL lamellae domains started to melt and the integrated intensity of the PCL Bragg peak decreases with increasing temperature. In the case of the PCL, however, the crystal domain size decreases only slightly. This indicates that the number of the PCL crystalline domains decreases during the melting.

Submicron vesicles immobilized on gold films were visualized in situ using environmental scanning electron microscopy (ESEM). Electron micrographs show that surface immobilized vesicles composed of diacetylenic phospholipids with 1 mole percent disulfide functionality and that encapsulate NaCl are structurally stable for at least three days. Furthermore, energy dispersive spectroscopy (EDS) provides compositional evidence supporting the formation of surface immobilized vesicles. Using ESEM coupled with EDS, a two-layer vesicle structure was imaged and found to contain NaCl and lipid elements sulfur and phosphorous.

In this study we describe the preparation and the characterization of a complex material using β-cyclodextrin covalently bound to Ni-Zn ferrite to obtain a magnetically targetable drug carrier. The physical-chemical characterization was performed through Fourier transformed infrared spectroscopy, X-ray diffraction, XRD, thermal analysis (TG/DTA), and atomic absorption spectroscopy. The results pointed out that β-cyclodextrin is externally covalently bound to Ni-Zn ferrite. However it was also verified that the β-cyclodextrin cavity is free and can include bioactive agents. The most interesting feature of this approach is the combination of magnetic properties and the host:guest technology to obtain an efficient targetable drug carrier system.

Resorbable calcium phosphate (CaP) thin films previously prepared only on quartz substrates were fabricated on Ti-6Al-4V implant grade titanium alloy. In order to maintain the characteristic phase composition and surface morphology of the CaP thin film, an intermediate silica barrier layer was deposited on the titanium alloy via chemical vapour deposition (CVD) using a metal organic precursor. CaP thin films were subsequently deposited on the intermediate SiO2 layer using the dip coating method, and sintered at 1000°C. The final sintered films have a multiphase composition consisting of calcium hydroxyapatite (HA) and a silicon stabilized form of alpha tri-calcium phosphate, or Si-TCP. The thickness of the silica barrier layers were evaluated in terms of the main CVD processing parameters using variable wavelength fixed angle ellipsometry and these parameters were optimized to best reproduce the characteristic CaP thin film. The phase composition and surface morphology of the CaP thin films were characterized using glancing angle X-ray diffraction and scanning electron microscopy.

An amino functional group was substituted on a PET film surface for the purpose of making the implantation of collagen readily. The PET has been widely used for medical materials such as an artificial ligament because of its strength and antibacterial action. However, when transplanted in human bodies, its compatibility is not good enough to adapt to the collagen which grows from living body tissues. To avoid this reaction medicine has been used clinically which makes the PET fiber into a mesh state and after the transplantation into a human body, makes the tissue intrude in the PET fiber. However, this method has not shown satisfactory enough results to promote rehabilitation. If the living body compatibility of materials is improved the initial adapting power with the tissue can be enhanced.

Then we substituted NH2, which has a high affinity for collagen, on the PET surface by ArF laser. PET is highly hydrophobic and does not dissolve well in aqueous solutions. To avoid this reaction we make a thin ammonium fluoride solution layer on the PET surface with capillary phenomenon. Then an ArF laser beam was irradiated vertically onto the sample. The result of this treatment shows that an untreated sample having the contact angle of 80° with water and the bonding strength of only 1.0 kg/cm2 with collagen was improved to have the contact angle of 22° and the bonding strength to be 12 kg/cm2.

When the treated sample had been implanted into the subcutaneous tissue of a rabbit's regiones dorsales, existence of leukocyte colonies that are indicators of human histocompatibility was confirmed on the hydrophilic parts of the sample.

The phase transition of solutions of the protein filaments F-actin from the isotropic (I) to the nematic (N) liquid crystalline state was studied by quantitative measurements of optical birefringence and fluorescence. The threshold protein concentration for the transition varies inversely with the average filament length, consistent with the prediction of statistical mechanics of rodlike suspensions based on the excluded volume effect. By measurements of local optical birefringence, a range of actin concentration is identified as the transition region between the isotropic and nematic phases. However, local measurements of the protein concentrations detect no discontinuity within a large number of samples in the transition region, suggesting that the I-N transition for F-actin occurs continuously over a defined concentration range. Thus the I-N transition appears to be of a higher order than the 1st, for F-actin of average filament length 3 μm or longer. Additionally, by mixing a tiny number of labeled actin filaments with the unlabeled ones, we observed thermal motions of individual filaments, thus ruling out an alternative picture, viewing an F-actin solution as an amorphous gel in which long filaments are too entangled or even cross-linked to allow partitioning of filaments into domains of discontinuous concentrations. We propose based on these experimental findings that either the extreme polydispersity of F-actin, or the large average filament length itself, renders the I-N transition to be a continuous one, in terms of both the average alignment of filaments and the protein concentration.

Conventionally, studies investigating the design of synthetic bladder wall substitutes have involved polymers with micro-dimensional structures. Since the body is made up of nano-structured components (e.g., extracellular matrix proteins), our focus has been in the use of nano-structured polymers in order to design a three-dimensional synthetic bladder construct that mimics bladder tissue in vivo. In order to complete this task, we fabricated novel, nano-structured, biodegradable materials to serve as substrates for bladder tissue constructs and tested the cytocompatibility properties of these biomaterials in vitro. The results from our in vitro work to date have provided the first evidence that cellular responses (such as adhesion and proliferation) of bladder smooth muscle cells are enhanced as poly (lactic-co-glycolic acid) (PLGA) surface feature dimensions are reduced into the nanometer range.