In this work we present both resonators working at ambient conditions and their first application as a biological and physical sensor. Singly- and doubly-clamped resonators of different geometries were realized using active layers of silicon carbide and aluminum nitride. The resonators were excited by magneto-motive actuation. The quality factor reached 350 and 50000 in air and in vacuum (2-5 10−5 mbar), respectively, which is sufficient for sensing applications in air. The resonance shift caused by mass loadings in the range of picograms and by single biological cells was measured at ambient conditions. Initial non-resonant measurements in liquids such as propanol were performed to investigate the possibility of viscosity measurements in small volumes such as microfluidic channels and droplets.

Micro-machined cantilevers coated with self-assembled monolayers (SAM) of alkanethiols are being utilized as sensing elements for new generation of high-sensitivity chemical and biological sensors. Presence of chemical species is detected by resolving the surface stress change associated with absorption/adsorption of analyte molecules on the sensitized cantilever. Challenges to widespread use of micromechanical cantilever sensors are: susceptibility to vibrations, integration in a single device and understanding the mechanism governing surface stress generation. In the current work, surface stress development associated with formation of self-assembled-monolayers of alkanethiols was characterized using curvature interferometry. In order to understand the molecular mechanism underlying the surface stress generation, a multi-scale model is developed to predict the surface stress generated during absorption of the alkanethiols on a gold film.

In this paper we describe the fabrication of nanostructure based ZnO ultra violet sensor by a simple route without involving the clean room processing of inter digitized electrodes. The ZnO nanostructures consist of micro spheres of dimension 600 nm- 2 microns embedded in the network of nanowires of dimension 40 nm. The optical properties are studied by Photoluminescence spectroscopy that revealed the exciton band gap of 3.2 eV at 383 nm. The ultra violet sensors exhibit 2 orders of UV to visible rejection ratio. The photo response of Ultra violet sensors as a function of electrode spacing will be discussed.

Nanofabrication is one of the driving forces leading to developments in a variety of fields including microelectronics, medicine, and sensors. Precise control over nanoscale architecture is an essential aspect in relating new size-dependent material properties. Both direct write methods and natural lithography's offer a unique opportunity to fabricate “user-defined” writing of nanostructures in a wide range of materials. Electron Beam Lithography (EBL) and Nanosphere Lithography (NSL) provide the opportunity to fabricate precise nanostructures on a wide variety of substrates with a large range of materials. Using electrodynamics calculations, Schatz and coworkers have discovered one and two dimensional array structures that produce remarkably narrow plasmon resonance spectra upon irradiation with light that is polarized perpendicularly to the array axis. In order to investigate these interactions, precise control of nanoparticle orientation, size, shape and spacing is necessary. If the overall structures have excessive defects then the effect may not be seen. For the two dimensional arrays, to have the best control over array fabrication and to look at these interactions experimentally, EBL was used to construct both hexagonal arrays of circular cylinders and the Kagome lattice. The interparticle spacing in each of these structures was varied systematically. Dark field microscopy was used to look at overall sample homogeneity and collect the single particle plasmon resonance spectrum. Additionally, both dark-field and extinction spectroscopies were used to look at the bulk spectral properties of each array type and each spacing. In investigating of the two dimensional arrays, the Kagome structure was also compared to samples produced by traditional NSL to study the optical interaction of defects, domains, and overall sample uniformity on the shape and location of the plasmon resonance. This work illustrates a deeper understanding in the nature of the optical coupling in nanostructures and this knowledge can be utilized in the future to fabricate designer (tailor made) substrates for plasmonic and surface-enhanced raman applications.

Phase composition and electrical properties of Ag(Tl)SbS amorphous films obtained by pulse laser deposition technology are investigated. The films deposited on crystalline NaCl and Kcl substrates are amorphous with crystalline phase inclusions. Room-temperature current voltage characteristics showed a good electro-sensitivity of the films under applied bias up to 10 V and a space-charge-limited current was registered as a principal component of the charge carrier transport.

One approach to improve the performance of current titanium implants is to create nanostructures via surface modification. Anodization is known to produce nanotubular structures on titanium surfaces when using fluorine containing solutions. Previous studies revealed enhanced osteoblast (bone-forming cell) adhesion and calcium deposition on anodized titanium possessing nanotubular structures compared to unanodized titanium. Moreover, it was found that protein adsorption (specifically, vitronectin and fibronectin) prior to cell adhesion increased on anodized compared to unanodized samples. These results all indicate that anodized titanium would be a good candidate for novel orthopedic implants. The nanotubes created by anodization have an inner diameter from 40 to 100 nm and a depth of a few hundred nanometers. In the present study, the drug delivery capability of such nanotubular structures was further characterized. Three different model drugs were tested: immunoglobulin G for foreign body response, bone morphogenetic protein active fragment for new bone growth, and penicillin/streptomycin for antimicrobial. First, these proteins were allowed to adsorb onto substrates for 24 h under room temperature. Then, the substrates with absorbed proteins were rinsed and transferred to new buffer solution kept at 37 °C. Buffer solution was collected and changed everyday. Finally, protein release from each substrate was measured using a commercial BCA assay kit. Results showed decreased immunoglobulin G adsorption, increased bone morphogenetic protein and penicillin/streptomycin adsorption on anodized titanium compared to unanodized ones. The release behavior of each protein on anodized and unanodized titanium is also studied.

The design, fabrication and characterization of liquid-filled microchannels embedded in silica layers and integrated with optical waveguides for applications in on-chip sensors and novel photonic devices are presented. These integrated microstructures are formed using plasma-enhanced chemical vapor deposition (PECVD), photolithography and reactive ion etching (RIE). Surface accessible fluid introduction ports have been developed, and microfluidic circuits including bends, T-junctions and splitters are demonstrated. Coupling of light from integrated solid silica waveguides via directional coupling or direct end-fire coupling into fluid filled channels has been achieved on-chip, and optical losses assessed experimentally and theoretically. Optimization of the microstructures for sensor applications and for novel photonic devices based on nonlinear and other optical properties of fluids in integrated liquid waveguide segments is discussed.

Nanorods/nanoparticles TiO2 with mesoporous structure were synthesized by hydrothermal method at 150 °C for 20 h. The samples characterized by XRD, SEM, TEM, SAED, HRTEM, and BET surface area. The nanorods had diameter about 10-20 nm and the lengths of 100-200 nm, the nanoparticles had diameter about 5-10 nm. The prepared material had average pore diameter about 7-12 nm. The BET surface area and pore volume of the sample are about 203 m2/g and 0.655 cm3/g, respectively. The nanorods/nanoparticles TiO2 with mesoporous structure showed higher photocatalytic activity (I3− concentration) than the nanorods TiO2, nanofibers TiO2, mesoporous TiO2, and commercial TiO2 (ST-01, P-25, JRC-01, and JRC-03). The solar energy conversion efficiency (η) of the cell using nanorods/nanoparticles TiO2 with mesoporous structure was about 7.12 % with Jsc of 13.97 mA/cm2, Voc of 0.73 V and ff of 0.70; while η of the cell using P-25 reached 5.82 % with Jsc of 12.74 mA/cm2, Voc of 0.704 V and ff of 0.649.

Stem cells are the source of all differentiated cells in the body. However, the stimuli that control stem cell differentiation into other cell types is still not well understood. In order to investigate this, novel carbon nanotubes (CNT's) were synthesized on anodized titanium substrates by chemical vapor deposition. Human mesenchymal stem cell (HMCS) adhesion was investigated on this nano-structured surface. The results showed significant evidence for the enhancement of HMSC adhesion on carbon nanotubes with respect to the template they were synthesized on, specifically, anodized titanium. Such evidence provides promise for the use of carbon nanotubes grown from anodized titanium to serve as novel stem cell differentiation devices.

We demonstrate a method for fabricating a variety of nanostructured metallic thin films by using one simple approach based on the use of anodic aluminum oxide (AAO) membrane as masking template. Highly-ordered large-area metallic nanopore- or nanotip-arrays (e.g., Ni, Ag, Au), with various sizes and shapes, were deposited onto AAO membranes through e-beam evaporation. Free standing nano-patterned metallic films were obtained after chemically removing the template and characterized using scanning electron microscopy and electrochemical methods. The nanostructured films will find use in a number of applications, such as plasmonics, electrochemical and biomedical analysis, and catalysis.

The effect of hydrogen partial pressure on the growth of CNT thin films using on-axis PLD has been studied. Using nickel as buffer layer, carbon nanotubes can be produced with good yield in Hydrogen atmosphere. We have found strong visible-near infrared (NIR) photoluminescence (PL) from carbon nanotube thin films synthesized under various hydrogen partial pressures. The present result shows that bright, narrow PL from CNTs can be obtained without any post growth processing.

The cytotoxicity of various surface functionalized gold and silver nanords was measured by MTT assays for two cell lines, fibroblast and HeLa. It was found that the functionalized nanorods with 200 nm diameter and length up to a few micrometer can be readily internalized by both types of cells regardless of the surface functionalization. However, the cytotoxicity of the nanorods was found to depend on the polarity of the surface charge. The positively charged amino end group on the nanorod surface was found to be the least toxic whereas the negatively charged carboxylic acid end group on the nanorod surface caused lots of cell death. In general, the functionalized nanorods were found to be more toxic than the serum coated nanorods.

Recently, the magnetostrictive microcantilever (MSMC) as a high performance biosensor platform was introduced. The MSMC is a wireless acoustic wave (AW) sensor and exhibits a high Q value. More importantly, the MSMC works well in liquid. In this paper, the detection of Bacillus anthracis spores using MSMCs with filamentous phage as the bioprobe is reported. The phased-coated MSMC biosensors were exposed to cultures containing target spores with increasing concentrations ranging from 5 × 104 to 5 × 108 spores/mL. By monitoring the shift in the resonance frequency of the MSMCs, the spores were detected in a real-time manner and a detection limit of 105 spores/mL was obtained for the MSMCs used in this research. Higher sensitivity is expected for the MSMCs with smaller size.

Magnetoelastic resonance biosensors were fabricated by immobilizing a bio-molecular recognition element onto the surface of Fe79B21 magnetoelastic particles (MEP). These sensors can be measured wirelessly and remotely for both in-air and in-liquid bacteria detection. Filamentous bacterio-phage that was selected specifically for the detection of Bacillus anthracis spores was employed as the biomolecular recognition element and immobilized onto the MEPs' surfaces. Attachment of the spores to the sensor surface due to specific phage-spore binding results in a shift in the resonance frequency of the biosensor. Insitu measurement of the resonance frequency of biosensors of 5×100×500 microns were used to determine the sensor response as a function of spore concentrations of 103 to 108 cfu/ml. Specificity of the sensor was evaluated by conducting tests using a mixture of Bacillus anthracis Sterne strain, Bacillus cereus and Bacillus megaterium spores.

The integrated application within random carbon nanotube networks (CNT) to carry and fuse information, as well as perform simple sensing, is explored. One may imagine small CNT networks with functionalized nanotubes simultaneously sensing multiple targets in-vivo for unprecedented understanding of biological pathways. This is clearly distinct from the traditional convoluted approach of using CNT networks to construct transistors that are in turn used to construct communication networks. With random CNT network layouts, routing of information is an integral part of the physical layer.

A Mathematica analysis for evaluating random CNT networks has been developed and used to verify design characteristics. The graph spectrum of the CNT network is used to determine resistance and electron mobility characteristics. Thus, we have been able to find relationships among CNT network structure and electron mobility. The nanotube density allows for an increase in the number of bits per square meter of information transfer compared to wireless communication. Consider a wireless network; a typical bit-meters/second capacity is limited in a traditional wireless network. The maximum wireless capacity approximation in a wireless broadcast media is contrasted with a CNT network; we look at the efficiency of CNT networks to carry information and compare with theoretical limits.

A nano-scale biosensor chip surface was fabricated using dinitro-phenylated key hole limpet (DNP-KLH) protein conjugate as ligand supported by underlying 11-amino 1-undecanethiol hydrochloride(AUT) self assembled monolayer (SAM) and bis sulfosuccinimidyl suberate(BS3) as crosslinker. Bioactive thin films were fabricated over gold chip via layer-by-layer self assembly methods. Biomolecular interaction between substrate specific anti-TNT antibody and DNP-KLH conjugate surface was monitored through surface plasmon resonance based optical sensor. The quantitation of tri-nitro toluene(TNT) on this bioactive surface was done using the solution based competitive inhibition assay. The DNP-KLH surface biosensor has shown a detection limit of 0.14 ng/ml(140 ppt) for TNT molecule. The detection limit of surface plasmon resonance(SPR) biosensor was further enhanced by using goat anti mouse antibody to the 0.002 ng/ml for TNT analyte. This TNT specific biosensor holds the promise to be one of most sensitive sensor surface under indirect competitive assay format. A short injection (12 sec) of 10 mM Glycine-HCl solution was found adequate for regeneration of DNP-KLH surface for repeated use.

We are developing label-free Arrayed Imaging Reflectometry (AIR) for rapid and multiplexed protein detection. AIR is based on the high dynamic range in reflected optical intensity near a point of zero reflectance on an antireflection coated substrate. The reflectance is therefore highly sensitive to changes in film thickness, allowing direct detection of molecular binding when appropriate probe molecules are immobilized on the surface. The simplest implementation of AIR uses a 633 nm HeNe laser and a silicon wafer substrate coated with ∼1400 Å of SiO2. This system has a reflectance zero for s-polarized HeNe light incident at ∼70°. This interference film is then functionalized with probe molecules designed to bind to a specific target, and this binding can be detected with high sensitivity in the reflectance signal. By expanding the laser beam and collecting the reflected signal with a CCD camera, large arrays of detection spots can be imaged simultaneously. Spot intensity increases relative to the amount of target binding and the target solution concentration can then be calculated. We have demonstrated the detection of the Enteropathogenic E Coli membrane protein Intimin at levels below 10 pM using receptor molecule Tir as a probe, and are currently evaluating various clinical targets using more common antibody probes.

Tin oxide (SnO2) with rutile structure is a wide-band gap semiconductor that has been used extensively in optoelectronic devices and sensors. A fibrous shape is especially favorable for the sensor applications. The authors synthesized micro-/nano- SnO2 fibers from a precursor solution of poly (ethylene oxide) (PEO), chloroform (CHCl3) and dimethyldineodecanoate tin (C22H44O4Sn) using electrospinning and metallorganics decomposition techniques. This paper uses Fourier-transform infrared spectroscopy, thermogravimetric and differential thermal analysis, and x-ray diffraction to reveal a series of chemical and physical changes from the starting chemicals to the final product of ultra-fine SnO2 fibers: the solvent CHCl3 evaporates during the electrospinning; the organic groups in PEO and C22H44O4Sn decompose with Sn-C bond in C22H44O4Sn replaced by Sn-O between 220 and 300°C, and transform into rutile structure between 300 and 380°C; the incipient rutile lattice develops into a relatively complete degree after sintering at higher temperatures up to 600°C.

A universal method is described to design and construct protein-nanoparticle assemblies controlled by nanoparticle functionality, and placement of genetic tag into proteins. Well-defined binding complexes of nanoparticles and two proteins, the adenovirus serotype 12 knob and the mycobacterium tuberculosis 20S proteasome, were formed through site-specific binding between 6x-histidine tags in proteins and nickel-nitrilotriacetic acid functional groups on gold nanoparticles.

Hydroxyapatite (HAp), tricalcium phosphate (TCP) and calcium pyrophosphate (CPP) are known to be among calcium phosphates used in clinical medicine due to their biocompatibility. HAp and other complex calcium phosphate salts are the end-products of the biological mineralization process. Calcium pyrophosphate Ca2P2O7 (β-CPP) is one of the intermediate products involved in this process. The biological response with respect to new bone formation is quite similar for CPP and HAp. Sintered CPP has better biological responses, and, thus, a great potential as a biodegradable bone substitute. The rate of biodegradation depends on: (i) material texture (porosity type and level), (ii) quality of biodegradation phase (phase composition, grain size, properties of grain boundaries). Several sources for CPP phase in ceramics can be assumed. CPP phase may come from frit (CaO-P2O5, Ca/P=0.2-0.75) used as a sintering additive. Ceramics can be fabricated from powder of CPP with Na4P2O7 as sintering additive, via interaction between H3PO4 or (NH4)2HPO4 and porous HAp at high temperature after soaking it in the former solutions. The aim of the present work was focused on fabrication of multiphase ceramics with enhanced resorptivity due to presence of CPP phase and investigation of processes leading to formation of the multiphase ceramics based on HAp and CPP originated from CaHPO4. Ceramic materials have been made from mixtures of powders of stoihiometric HAp (Ca/P=1.67) and monetite (CaHPO4, Ca/P=1). Powders of HAp and monetite were synthesized by means of wet chemical precipitation from aqueous solutions of Ca(NO3)2*4H2O and (NH4)2HPO4 at 60 °C and pH=9 for HAp and pH=4-5 for monetite. Component ratio HAp:monetite was varied from 0:100 to 100:0 % with a step of 20%. Powders of raw materials and the mixtures were tested by means of XRD, TG, DTG, SEM, dilatometry. Linear shrinkage, density and microstructure of samples of ceramic materials sintered at 900, 1000, 1100°C with isothermal holding during 6 hours were tested. Complicated consequence of phase transformations took place during heating the the mixtures from 20 to 1200 C. The CPP (Ca/P=1, converted from CaHPO4 at 400-500°C ) reacts with HAp (Ca/P=1.67) causing additional weight loss in the region of 600-1050°C due to solid state reaction leading to TCP (Ca/P=1.55) formation. Linear shrinkage of HAp at 1100°C after 6 hours was found to be about 21%; for Ca2P2O7 formed from monetite, and for the mixtures - less than 11%. Resulted ceramics with the phase composition of HAp, CPP and TCP, i.e. with a different content of degradable phase and different ratio of CPP/TCP, can be treated as a biocompatible bioactive material with a tunable rate and limit of biodegradation.