Zinc Oxide nanoparticles (ZnO) being biocompatible and chemically stable have great potential for bio-medical applications that includes anti-bacterial and mold prevention, air ventilation and purification, water purification, self cleaning and photosynthesis, and disease detection. Also ZnO is a wide band gap semiconductor and exhibits piezoelectric and pyroelectric properties, which makes it a perfect candidate for building electrochemically coupled sensors and transducers. With all these unique properties, ZnO has the potential to be very important nanomaterial in material research area. Therefore, research, development, and production of ZnO nanoparticles would make notable contributions to the field of nanotechnology. In this paper we report a novel approach for the fabrication of ZnO nanoparticles suspension in deionized water at room temperature using pulsed laser deposition (PLD) technique. Particle size was controlled by the number of shots of the laser beam used. Characterization of the nanoparticles has been done using UV-Visible spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), and dynamic light scattering (DLS). UV-Visible study confirmed the existence of ZnO nanoparticles showing a peak at around 300 nm which is consistent with the absorption spectra of standard ZnO nanoparticles. Presence of ZnO was reconfirmed by the excitation and emission spectra obtained from fluorescence spectroscopy. The excitation and emission peaks were found at 305 nm and 410 nm respectively, strongly suggesting the characteristic peaks for ZnO nanoparticles. Transmission electron microscope (TEM) photographs established that we have successfully prepared ZnO nanoparticles suspension with particle size ranging from 6 nm to 90 nm.

We herein report a facile, ‘green’ one- step synthesis of a series of monodispersed water-soluble selenide nanoparticles at room temperature. The capping ligands used include, cysteine, methionine, ascorbic acid and starch which function as agents of solubilisation, stabilization and conjugation sites for biomolecules. The synthetic approach involves the addition of an appropriate volume of selenide ion produced via the reduction of selenium powder in water to an aqueous solution containing the ligand- metal salt (MCl2 M = Zn or Cd). Optical spectroscopy shows that the particles are of high quality while the transmission electron microscopy (TEM) of the samples shows variation in shapes ranging from dots to rods of high and low aspect ratios.

This paper discusses preparation, characterization and measurement of linear DC and AC magnetic properties of magnetite (Fe3O4) nanoparticles (size ranges of 7-50 nm and 5 microns) and polymer composites of those particulates. Selected data and analysis are taken from the PhD thesis of Liong [1]. The goal of this research is to obtain magnetic data, specifically magnetization, anisotropy and coercivity as functions of particle size. These will be used as inputs to non linear magnetic simulations and in planning for future nonlinear magnetic measurements. Magnetite nanoparticles were synthesized by chemical coprecipitation, a method that allowed for the production of samples in gram quantities. Vibrating sample magnetometry was used to measure the room-temperature DC magnetization and coercivity of the particulates. Coaxial line impedance measurements were used to measure low frequency and dispersive AC permeability of Fe3O4–polymer composites from 1 Megahertz to 10 Gigahertz. AC data are applied to infer particulate magnetic susceptibility and anisotropy field change with particle size. Particle size was calculated from XTD data and supported by TEM images.

Measured DC saturation magnetization and coercivity decreased with particle dimension while anisotropy was calculated to increase. Magnetization data are consistent with models that calculate nanoparticle magnetization as a volumetric average of a spherical bulk material core and a passive outer shell. The shell thickness was calculated at 0.84 nm, very near one lattice constant of bulk Fe3O4, 0.8394 nm. Composites containing particulate volume fractions less than 20% were fabricated. Effective media theory was applied to measured AC composite permeability to extract particle magnetic properties and thereby anisotropy field, which increased by an order of magnitude from the bulk. Permeability decreased with particulate size.

In this study, we focus on effect of diamond-like carbon (DLC) coating on scaffold for tissue engineering. DLC film was deposited on segmented polyurethane (SPU) scaffold sheet which consists of micro SUP fibers. Structural and compositional effects of the DLC film coating were investigated on cell growth as an investigation of biological response. The surface composition, morphology, structures, and wettability of the DLC film coating was estimated by using X-ray photoelectron spectrometer (XPS), Scanning Electron Microscope (SEM), Ar-laser Raman spectrophotometer (Raman), and contact angle measurement. And then, human umbilical vein endothelial (HUV-EC-C) cells were grown on the DLC coated scaffold sheet. The results presented here suggest that DLC film coating is promising approach to improve biological for tissue engineering.

Heterogeneous, one-dimensional (1D) nanomaterials, such as nanorods and nanowires, have been utilized for a variety of different biomedical applications because they offer a unique combination of properties and provide a material platform for integrating multiple functions. In this paper, we propose a template-assisted wetting approach to fabricate segmented polymer nanorods using biodegradable polymers for controlled drug delivery. Our previous work with polystyrene (PS) and poly(methyl methacrylate) (PMMA) heterogeneous, segmented nanorods is described briefly to introduce our current preliminary work with the fabrication of homogeneous biodegradable nanorods and drug release from polymer thin films. Since the template-assisted fabrication approach provides us unprecedented control over the size, spacing, and length of the heterogeneous polymer nanorods, this technique will provide for the opportunity to evaluate drug release kinetics as a function of the segment spacing, size of the nanorods, and aspect ratio in the future.

The current clinical treatment of cartilage defects involves autologous chondrocyte implantation into cartilage defect sites. However, one of the complications associated with this method is the lack of bonding between the implanted materials and natural tissue. Helical rosette nanotubes (HRNs) are novel biomimetic self-assembled supramolecular structures whose basic building blocks are DNA base-pairs. HRNs are similar in size to collagen in cartilage. Moreover, previous studies have shown that HRNs are biocompatible and increase the adhesion of numerous cells compared to other commonly used cartilage implant materials (like hydrogels and Ti). In addition, HRNs can solidify into a viscous gel at body temperatures under short periods of time. Thus, it is hoped that HRNs can serve as a novel in situ tissue implant to improve cartilage cell adhesion and functions. In this study, in order to heal cartilage rupture and regenerate cartilage during possible implantation, the mechanical properties of select hydrogel/HRN composites were tested. In addition, electro-spinning was used to generate three-dimensional, implantable, composite fibers encapsulated with chondrocytes and fibroblast-like type-B synoviocytes (SFB cells, a type of mesenchymal stem cell). Importantly, results showed that drug-delivered HRNs enhanced hydrogel adhesive strength and created a scaffold with nanometer-rough surface structures pertinent for cartilage regeneration. In this manner, this study provided an alternative cartilage regenerative material which relies on nanotechnology that can be injected as a liquid, solidify at body temperatures under short periods of time, have suitable mechanical properties to collagen, and promote cell functions.

Graphitic shells coated ferromagnetic cobalt nanoparticles (C-Co-NPs) with diameters of around 7-9 nm cubic crystalline structures were synthesized by catalytic chemical vapor deposition (CCVD). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis indicated that the Co-NPs inside the carbon shells were preserved in the metallic state. Confocal microscope images revealed effective penetrations of C-Co-NPs through plasmatic membranes into the nucleus of the cultured HeLa cancerous cells. Low RF radiation of 350 kHz triggered the cell death, process that was found to be dependent on the NPs concentration and application time. Compared to carbon nanostructures such as single wall carbon nanotubes, super paramagnetic cobalt nanoparticles demonstrated higher specificity for RF absorption and heating. This work indicates a great potential of a new technology for tumor thermal ablation.

The idea of using nanocrystalline diamond (NCD) as a coating on orthopedic implants originates back to the last century since NCD possesses superior mechanical and tribological properties as well as chemical stability. However, it has only been within recent years that the interactions between NCD and osteoblasts (OB, bone forming cells) have been investigated. In this study, the impact of NCD surface topography on OB functions including proliferation (24 hrs to 48 hrs) and differentiation (7 to 21 days) was studied. NCD of varied grain sizes (from less than 100 nm to approximately 600 nm) were fabricated by microwave plasma enhanced chemical-vapor-deposition and characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Surface topography of the NCD changed dramatically as grain size grew. OB proliferation on these coatings was studied by SEM after incubation for 24 hrs and 48hrs, respectively. OB differentiation on diamond coatings after incubation from 1 to 3 weeks was investigated by alkaline phosphatase activity and calcium deposition. Results demonstrated that OB proliferation and differentiation were dependent on topography with NCD grain sizes less than 100 nm exhibiting the best OB responses. To explain this enhancement, OB filopodia protrusions on different NCD were observed by SEM and the results revealed that surface topography of NCD played a crucial role in OB filopodia extensions. In summary, these findings provided important design criteria for creating proper NCD surfaces for orthopedic coatings and also provided cues on promoting interactions between nanostructured surfaces and cell responses.

Gold nanorods have a strong surface plasmon band at the near infrared region. The absorbed light energy is then converted to heat. Since near infrared light can penetrate deeply into tissue, gold nanorods are expected to be used as a contrast agent for bioimaging using the near infrared light and photosensitizers for photothermal therapy. The surface plasmon bands of intravenously injected the gold nanorods were directly monitored from the mouse abdomen by using a spectrophotometer equipped with an integrating sphere. The absorbance at 900 nm from PEG5,000-modified gold nanorods immediately increased after injection and reached a plateau. The injection of phosphatidylcholine-modified gold nanorods also increased the absorbance at 900 nm, but the absorbance decreased single exponentially with a 1.3-min half-life. To demonstrate photothermal tumor therapy, the PEG-modified gold nanorods were directly injected into subcutaneous tumors in mice, then, near infrared laser light was irradiated to the tumor. After the treatment, significant suppression of tumor growth was observed.

There has long been a drive to produce sensors with ever-increasing sensitivity and selectivity, while also achieving robustness and ease of use. Nanoparticle-based sensing approaches have generated a great deal of attention and excitement, because they possess such qualities. For these assays to function properly, it requires the integration of molecular recognition motifs and materials with outstanding optical properties. Aptamers are DNA or RNA sequences that bind analytes with high specificity, which makes them a suitable choice as recognition elements. Changes in the surface plasmon resonance (SPR) of gold nanoparticles (AuNPS) as a function of interparticle distance, has been used as an optical signal to detect the presence of different species in solution by the naked eye. In this work, we coated gold nanoparticles with short oligonucleotides and aptamers for the design of sensors that can be used under different conditions, including salt concentration, pH and temperatures. Three aptamer sensors were developed using this approach 1) riboflavin, as a general indicator of biological activity, 2) ricin, a toxin that is of broad interest, and 3) theophylline, an adenosine antagonist. Our designs are based on two approaches, the first method consisted of the use of two sets of AuNPs, each coated with a short oligonucleotide complementary to a different part of the sequence of the aptamer of interest. Hybridization of the DNA-coated particles (DNA-AuNPs) with the free aptamer produced aggregates, i.e. 3-part design. The second approach consisted of the use of only two sets of DNA-AuNPs, one coated with an aptamer that contains a thiol group in its 5′ end, and the second set of AuNPs coated with a sequence complementary to part of the aptamer. Hybridization of these two sets of particles produced aggregates, i.e. 2-part design. In both cases, the presence of the analyte promoted a change in the conformation of the aptamer, which caused the dehybridization of the complementary sequences. This conformational change of the aptamer upon binding of the analyte produced the dissociation of the nanoparticle aggregates, which is translated into a change in the color of the suspensions from blue to red. In this presentation, we will compare the advantages and disadvantages associated with a 3-part versus a 2-part nanoparticle-oligonucleotide reporting assay.

This paper reports on the incorporation and validation of a microagitation system based on a piezoelectric polymer, Poly(vinylidene fluoride) in its beta phase, β-PVDF, in a fully-integrated disposable lab-on-a-chip for point-of-care testing and monitoring of biochemical parameters in biological fluids. The lab-on-a-chip concept offers a novel approach for clinical analyses, especially in biological fluids analyses, due to its portability, ensuring that the analysis can be performed at any location with quick results. Its microagitation system performance was successfully demonstrated by quantitative measurements of uric acid in human urine, though other molecules or biological fluids can be also measured. The optimization tests prove that it is possible to use lower frequencies than resonance with no major changes in the mixing process. The effect of area and location within the lab-on-a-chip of the microagitation system was also considered.

The impact of device dimension and architecture on the device performance of an all–solution fabrication organic thin film transistor (OTFT) has been investigated. The saturation drain current is inversely proportional to the channel length, indicating that a characteristic of field–effect like transistor has been obtained. In contrast, the drain current is independent of the thickness of polyvinylphenol (PVP) dielectric layer and a large leakage current is observed at the gate electrode indicating that the device also shows electrochemical transistor characteristics. Although separate conductance measurements of a single poly(3–hexylthiophene) (P3HT) layer and a P3HT/PVP layer reveal that the conductance is proportional to the thickness of the layer, the maximum achieved drain current in the fabricated OTFT is inversely proportional to the P3HT thickness. Using this data, an interface of P3HT/PVP or a maximum P3HT thickness for a working transistor of approximately 160 ± 16 nm can be extracted. The mechanism of operation of these devices is discussed.

Our work presents results on human plasma protein adsorption onto a polyacrylic acid (PAA) film prepared via surface wave plasma (SWP) induced graft polymerization. The PAA film prepared in this manner is characterized by a carboxyl functional group and a constant contact angle in water of 35°. The adsorption kinetics of human plasma fibrinogen (HPF) and human serum albumin (HSA) proteins were measured by in-situ UV-ATR spectroscopy. The free energy of adsorption on PAA treated as well as untreated surfaces was −28 kJ M−1 and −22 kJ M−1 for HPF and HSA, respectively, regardless of surface chemistry. We determined that 14 μM and 6 μM HPF concentrations are enough to cover half of the maximum possible of surface coverage on silica and PAA film, respectively. HSA protein concentrations of 154 μM and 118 μM are enough to cover half of the maximum accessible surface of silica and PAA film, respectively. For surface treatment of implants with PAA polymer and protein, the necessary protein concentration for effective surface coverage should be known.

This paper reports a novel and cost-effective approach which enables the integration of nanostructures and micropatterns. In this work nanofibers are selectively patterned in defined micropatterns via a collector chip. The driving momentum of the micropattern formation, namely the non-uniform electrical field, is studied by finite element method. Micropatterned nanofiber mats are successfully fabricated. The SEM characterization demonstrates that the microstructures are manifested by distinct porosities and thicknesses. This work opens a door for a broad array of applications such as nanoelectronics and tissue engineering, where the fibrous materials with the characteristic features sizes over several order of magnitudes are required.

In this work, we combine nanoscale engineering with single-molecule biology to probe the biochemical interactions between individual proteins and DNA. This approach, a vast improvement over previous methods, constructs a platform to observe thousands of protein-DNA interactions in real time with unprecedented detail. A key challenge in these experiments involves collecting enough statistically relevant data in order to analyze reactions which are designed to be probed individually. “DNA curtains” are formed by flowing the DNA tethered to a lipid bilayer across nanopatterned barriers, facilitating massively parallel data acquisition.

The concept uses nanoparticles or quantum dots that possess a bandgap that when an electron hole pair is generated by irradiating with photons above their bandgap would emit photons with a wavelength in the far ultraviolet (UV) region from about 300 down to 180 nanometers.

This is the so-called germicidal ultraviolet light regime whose peak is centered at about 270 nm where all organisms (viruses, bacteria, parasites and molds) or cells that contain DNA or RNA are susceptible to mitigation.

It has been shown by Shreier, et al (Thymine Dimerization in DNA is an Ultrafast Photoreaction, Science, Vol 315, 2 Feb. 2007, pgs 625-629) that when DNA, for example, is irradiated with UV light of 272 nm in wavelength the chemical bonds of the thymine base pairs of the DNA helix are broken and the ends dimerize to open up the helix thereby preventing it being a template for the production of another cell or organism resulting in apoptosis. By using femto-second time resolved infrared spectroscopy they found that the dimers are fully formed in about 1 picosecond. In this therapy concept the nanoparticle or quantum dot would first be made biocompatible with a coating such as dextrin to make it compatible with the body. Then an appropriate ligand, conjugate or monoclonal antibody would be attached to the particle that would be specific for attaching to the target organism or cell. In the case of cancer cells most have surface specific antigens that are unique to the cancer cell and not to normal cells. Monoclonal antibodies have and can be made to bind to these sites and not to normal cells. The treatment then would entail injecting these bioconjugated nanoparticles that possess the appropriate bandgap into the patient. The particles that did not attach would be excreted through the patient's renal system. After an appropriate interval the patient would be irradiated with x-rays in the KeV to MeV range. The particles would then emit large quantities of UV photons for every KeV or MeV absorbed x-ray photon that would disrupt the cell or organism's DNA that it was attached to leading to apoptosis of the cell or organism.

U.S. and international patents have been applied for on the concept and, currently, two cancer researchers are in the process of being licensed to carry out research and development on the concept for the treatment of cancer.

Pulsed laser deposited cerium oxide (CeO2) nanoporous thin film on platinum (Pt) coated glass has been used for immobilization of glucose oxidase (GOx) by electrostatic interaction. Atomic force microscopy studies reveal the formation of nanoporous surface morphology of CeO2 thin film. Differential pulse voltammetric and optical measurements show that the GOx/CeO2/Pt bioelectrode is sensitive to the detection of glucose over the concentration upto 300 mg/dl. A low value of enzyme's kinetic parameter (Michaelis-Menten constant∼1.01 mM) indicates enhanced enzyme affinity of GOx to glucose.

An electrochemical capacitive sensor with electrode separation in the order of the Electrical Double Layer width (Debye length) of the analyte solution is presented for extremely sensitive and label-free analysis of Nucleic Acids. As the Electrical Double Layers (EDL) from both the capacitive electrodes interact and overlap each other in the reduced space confinement, the contribution from the electrode polarization effects and noises due to bulk sample resistance are found to be minimized. The dielectric property changes during hybridization reaction were measured using 10-mer nucleotide sequences. A 30-45% change in relative permittivity (capacitance) was observed due to DNA hybridization at 10Hz.

This work presents the study on the recognition and absorption of the water-soluble X-ray contrast medium iodixanol in aqueous solution using synthetic molecularly imprinted polymers (MIPs). A non-covalent imprinting technique was applied to prepare iodixanol-imprinted polymers using 4-vinylpyridine as the functional monomer and ethylene glycol dimethacrylate as the cross-linker. The effects of quantity of iodixanol templates, the crosslink density, and the solvent were studied in terms of the binding capacity and imprint effect of the polymers. UV-vis spectrometric analysis shows that the highest binding capacity achieved is 284 mg iodixanol per gram of dry polymer, which is 8.8 times higher than the binding capacity of the non-imprinted control polymers (NIPs). SEM and BET surface analysis have also been performed to investigate the effect of morphology and porosity on the binding capacities of polymers.