Template-assisted electrohydrodynamic atomization (TAEA) sprayingdeposition, a recently developed and an electric-driven jet-based techniquehas been used to prepare bioactive surface topography on titanium (Ti).Nanometer-scaled SiHA (nanoSiHA), which closely resembles the bone mineral,has been synthesized and deposited on Ti surfaces with a range of patterns,such as pillars and tracks. A human osteoblast (HOB) cell model has beenused to evaluate the in vitro cellular responses to nanoSiHA deposition.alamarBlue™ assay showed that nanoSiHA patterns are able to encourage theattachment and growth of HOB cells in comparison to those of nanoSiHAcoating. The preferential growth of HOB cells was found along and across thetrack, HOB cells were also found to stretch between two tracks. Imageanalysis of HOB cell responses to the size of nanoSiHA pattern showed thatthe length of HOB cells was proportional to the gaps between the tracksuntil reaching the maximum length of 110 μm. The results indicate that thedistance between the structures is paramount over the width. Our study willpave the way to control and guide cellular responses for new generation ofbone implants.

We analyze the apo and holo calmodulin (CaM) structures by sequentiallyinserting a perturbation on every residue of the protein, and monitoring thelinear response. Residue crosscorrelation matrices obtained from 20 ns longmolecular dynamics simulation of the apo-form are used as the kernel in thelinear response. We determine two residues whose perturbation equivalentlyyields the experimentally determined displacement profiles of CaM, relevantto the binding of the trifluoperazine (TFP) ligand. They reside onstructurally equivalent positions on the N- and C-terminus lobes of CaM, andare not in direct contact with the binding region. The direction of theperturbation that must be inserted on these residues is an important factorin recovering the conformational change, implying that highly selectivebinding must occur near these sites to invoke the necessary conformationalchange.

We aim to utilize the high surface area of a porous silicon (PSi) matrixcoupled with semiconductor quantum dot (QD) amplifiers for ultrasensitiveoptical detection of small biomolecules using a dual-mode detection scheme.In our system, QDs attached to the target biomolecule serve as signalamplifiers by providing an additional refractive index increase beyond thatof the smaller target molecules. The strong photoluminescence (PL) from theQDs serves as a secondary indication of target molecule attachment in thepores. A resulting increase in optical thickness of ∼190 nm and detectionsensitivity of ∼700 nm/RIU have been demonstrated for attachment ofglutathione capped CdTe QDs in the porous silicon matrix. Reflectance and PLmeasurements, combined with simulations, have been used to characterize thesurface area coverage of the QDs within the porous framework, which isestimated at 10% for glutathione capped CdTe QDs.

Operations on biological living cells and molecular devices have drivenresearch towards implementation of high-aspect-ratio nano-needles. However,current nano-needle fabrication is complicated to control the sizes andangles. In this work, we develop a simple method to fabricate repeatable andintegrated circuit (IC)-compatible sharp silicon nano-needles based on boronetch-stop in tetramethyl ammonium hydroxide (TMAH) solutions, and the needleangles can be accurately controlled. An analytical model is proposed toefficiently predict the needle sizes and explain the etching evolution ofsilicon nano-needles.

A key issue in using Polydimethylsiloxane (PDMS) based micropillars ascellular force transducers is obtaining an accurate characterization ofmechanical properties. The Young’s modulus of PDMS has been extended from aconstant in the ideal elastic case to a time-dependent function in theviscoelastic case. However, the frequency domain information is of morepractical interest in interpreting the complex cell contraction behavior. Inthis paper, we reevaluated the Young’s relaxation modulus in the time domainby using more robust fitting algorithms than previous reports, andinvestigated the storage and loss moduli in the frequency domain using theFourier transform technique. With the use of the frequency domain modulusand the deflection of micropillars in the Fourier series, the forcecalculation can be much simplified by converting a convolution in the timedomain to a multiplication in the frequency domain.

Our work focuses on the earliest events of homo-/heterogeneous nucleationfrom an initial supersaturated solution to the subsequent growth of nuclei.The combined use of conductance, together with hydrogen and calcium ISEs hasprovided new insights into the mechanisms of crystal nucleation and phasestability. We propose that two types of ACP are formed during HAPnucleation. The initial subcritical calcium-phosphate ion clusters form anamorphous [CaHPO4·xH2O] phase (ACP-1), whichtransforms to amorphous [Ca3(PO4)2](ACP-2), and subsequently to HAP. This study is a major step forward in ourunderstanding of the earliest nucleation events in vitro and in vivo.Additives may influence HAP nucleation by interacting with ACP clustersduring the early induction period.

We present a versatile and facile route for highly sensitive detection ofanalytes through coupling the enlargement of gold nanoparticles (Au NPs)with fluorescence decrease. The fluorescence intensity of dye molecules(e.g., fluorescein or rhodamine B) significantly decreased with theincreasing concentration of reducing agents, such as hydrogen peroxide andhydroquinone. The sensitivity for the detection of reducing agents was muchhigher than other detection methods based on the absorbance measurement ofenlarged gold nanoparticles or quantum dot-enzyme hybridization. We couldsuccessfully detect acetylthiocholine with the detection limit of several nMorders, using an enzymatic reaction by acetylcholinesterase, a key route forthe detection of toxic organophosphate compounds. The fluorescencedecreasing approach described in this work requires only a simple additionof fluorescence dye to the reaction solution without any chemicalmodification. The strategy of fluorescence decrease coupled withnanoparticle growth will be applied on the fluorescent substrate to developdetection templates for highly sensitive optical biosensor.

We describe the biosynthesis and characterization of protein materialscomprised of two distinct self-assembling domains (SADs): elastin (E) foundin tissue for its elastic properties and cartilage oligomeric matrix proteincoiled-coil (COMPcc, C) predominantly locatedin joint and in bones. Based onearlier studies on protein block polymers comprised these two SADs,orientation and number of blocks play a crucial role in the overallstimuli-responsive supramolecular assembly behavior. Here we fabricate arange of EnC and CEn block polymers in which the Edomain is systematically truncated to explore the effects of the E domain onthe overall physicochemical behavior.

Freestanding, strip-shaped magnetoelastic (ME) biosensors are a class ofwireless, mass-based biosensors that are being developed for the real-timedetection of pathogenic bacteria for food safety and bio-security. The masssensitivity of these biosensors operating in longitudinal-vibration modes isknown to be largely dependent on the position of masses attached to thesensor surfaces. Hence, considering this dependence is crucial to thedetection of low-concentration target pathogens, including single pathogenicbacteria, because their local attachment may cause varying sensor responses.In a worst case scenario, the resultant sensor responses (i.e., mass-inducedresonance frequency changes of the sensor) may be too small to be detecteddespite the attachment of the target pathogenic masses. To address theissue, phage-coated ME biosensors (magnetostrictive strips (4 mm × 0.8 mm ×30 μm) coated with a phage probe specifically binding streptavidin protein)with localized masses (streptavidin-coated polystyrene beads) werefabricated, and mass-position-dependence of the sensor’s sensitivity underthe fundamental-mode vibration was experimentally measured. In addition,three-dimensional finite element (FE) modal analysis was performed using theCalculiX software to simulate the phenomena. The experimental andtheoretical results show close agreement: (1) the mass sensitivity was lowwhen the mass was positioned in the middle of the sensor’s longest dimensionand (2) a much higher mass sensitivity was, by contrast, obtained for theequivalent masses placed at both ends of the strip-shaped sensor.Furthermore, FE models were constructed for differently sized, phage-coatedME biosensors (100 – 500 μm in length with different widths and thicknesses)loaded with a single bacterial mass (2 μm × 0.4 μm × 0.4 μm, 1.05 g/cm3) at varying longitudinal positions. The mass sensitivitywas found to be approximated by a mass-position-dependent Boltzmann functionwhose amplitude is inversely proportional to the length squared, width, andthickness of the sensor.

Cortical and cancellous bones were demineralized and deproteinized using 1 NHCl and 6% NaOCl, respectively. Experiments were performed at 37°C. The rateconstants were calculated and the structural features of untreated andcompletely demineralized and deproteinized samples were studied by scanningelectron microscopy, showing that intact, contiguous structures wereobtained. For both cases, the rate constant was higher for cancellous bonethan the cortical bone.

Chemotaxis is one of the essential mechanisms responsible for variouscomplex biological processes. For a crawling cell, the interface between thecell and the substrate plays an important role in the chemotactic migration.This paper presents a three-dimensional dynamic model to investigate theeffect of the interface between a crawling cell and a substrate on itschemotaxis. The coupled mechanisms of chemotaxis, the surface energy of thecell, and the interface between the cell and the substrate are incorporatedinto a diffuse interface model. Simulations reveal rich dynamics of acrawling cell associated with the interfacial condition, and confirm thehigh possibility of adequate predictions.

We have developed a reproducible protocol for studying the effect ofmicrowave radiation on the mechanical behavior of Bombyx mori cocoon silk. In the course of this work, we identifiedmultiple improvements that can be made to ASTM F 1317-98, the standardaccording to which microwave oven power output is calibrated.

Exposure to microwaves does not significantly affect mechanical propertiesof silkworm silk, if samples are kept in a desiccator after degumming (orafter degumming and microwaving) and prior to testing in a dry environment.This finding contrasts with previous work in which samples were not kept ina desiccator, and were tested in a relatively humid environment.

Because the effect of microwave radiation on the mechanical behavior of silkis sensitive to ambient moisture, meaningful comparison or pooling of testresults acquired in different laboratories is contingent on standardizationof both the sample storage environment and the environment in which samplesare tested. Interpretation of the extensive existing literature on silkmechanical properties must take account of the reality that the samplestorage and testing environments are not standardized and are usually notreported.

The dissolution kinetics of type B carbonate apatite (CAp) disks sintered atdifferent temperatures were investigated under acidic conditions similar toan osteoclastic desorption process in bone remodeling. The type B CAp disks,which were uniaxially pressed at 98MPa and sintered at temperatures of 600to 700 ºC, showed single crystalline phase and a high relative density of60-62 % compared to the stoichiometric density of 3.16g/cm3 ofhydroxyapatite (HAp). The dissolution rate of type B CAp disks sintered at650 ºC was 3.5 times faster than that of HAp disks at 650 ºC. These resultsindicate that the Type B CAp sintered disks show potential use as abiodegradable material for artificial bone.

We report the heterogeneous integration of a multifunctional sensor based onpolymer porous photonic bandgap (P3BG) structure and xerogelbased luminescence sensor technology. The P3BG structure wasfabricated using holographic interferometry. Initially, holographicinterferometry of a photo-activated prepolymer syrup that included avolatile solvent as well as monomer, photoinitiator, and co-initiator wasused to initiate photopolymerization. Subsequent UV curing resulted in welldefined lamellae of the polymer separated by porous polymer regions thatcreated a high quality photonic bandgap structure. The resulting P3BG structure was then integrated with the xerogel basedluminescence element to produce a luminescence sensor with a selectivenarrow band reflector. The prototype xerogel based luminescence sensorelement consisted of an O2 sensing material based on spin coatedtetraethylorthosilane (TEOS) composite xerogel films containing tris(4,7-diphenyl-1,10-phenanthroline) ruthenium (II) ([Ru(dpp)3]2+) luminophore. We demonstratedenhancement of the signal-to-noise ratio (SNR) of this integratedmultifunctional sensor while maintaining the same sensitivity to O2 sensing of the xerogel based element. The resultingadvantages and enhanced SNR of this integrated sensor will provide atemplate for other luminescence based assays to support highly sensitive andcost-effective sensor systems for biomedical applications.

Today the company seeks alternative natural medicine that are compatiblewith the body, which does not produce side effects and hang time are easilyaccessible and cost of those who currently have. The concern of researchersand specialists in the development of new materials is to seek, toexperiment and create products that can be useful and compatible with humanbeings so as to obtain a curative effect without a side effectoriginates.

The development of pharmacologically active materials has increased inrecent years. People lack access to most drugs and is therefore a need formore rapid and less expensive than current, which can be applied to cellularsystems in vitro, in order to evaluate the biocompatibility of newmaterials. The current study seeks to experiment in a new line of researchthat helps health care and have a better quality of life.

The excipients in the drug are auxiliary substances that help the activeingredient is the one with the therapeutic action, can be formulated in aneffective and pleasant for the patient. It is one or more substances thatare incorporated into the product to facilitate its preparation, maintenanceor administration. We therefore tested clay known as bentonite to serve as avehicle for transport of an active substance (ursolic acid) [1] and somescientific studies have shown that it possesses anti-inflammatory,antibacterial, antifungal and highly cytotoxic capacity. Both materials weremixed to generate a new biomaterial that has anti-inflammatory activity.Evaluation of this model was under the inhibition of edema produced by13-acetate-12-ortho-tetradecanoylphorbol (TPA) in mouse ear.

Partially demineralized (DM) bone is of interest due to its promisingosteointegrative properties for advanced bone grafts. Structural features ofpartially DM (35 vol.%, 45 vol.% and 55 vol.% reduction), and untreatedcortical bone samples were studied by scanning electron microscopy.Mechanical properties were investigated by compression testing in threeanatomical directions at different stages of DM. The radial directionappears to be the stiffest and strongest bone direction for the all DMstages.

The atypical mechanical behavior of white matter and its influence on themechanical properties of brain tissue necessitate adoption of a mutli-scalemodel of white matter for accurate computational analysis. Herein, wepresent a micromechanical analysis coupled with finite elements into abiomechanical interacting model of white matter. A representation of thewhite matter of central nervous system is identified and its microstructureis generated. The geometric descriptions of the axon and the surroundingmatrix are obtained from neurofilament immunohistochemistry images.Consecutively, linear elastic material constitutive models are applied todescribe the behavior of axons and their surrounding matrix subjected tosmall deformations. This model facilitates determination of the tissue’sstress and strain fields, and enables an understanding of the effects ofaxon undulation on local fields. The fundamental nature of the model enablesfuture scale-up for structural tissue analysis and predictions of axondamage at the microscale.

This article presents the first man-made material based on the structure ofnacre that successfully duplicates the mechanism of tablet sliding. Thismaterial was made of millimeter size PMMA tablets arranged in columns andheld by fasteners. Strain hardening was provided by tablet waviness,delaying localization and leading to strains at failure 3-5 times greaterthan bulk PMMA. Analytical and finite element models successfully capturedthe locking mechanisms, enabling a rigorous design and optimization ofsimilar composites based on different materials or at different lengthscales. This work demonstrates how key features and mechanisms in naturalnacre can be successfully harnessed in engineering materials. Interestingly,the development of this model material and of its associated models alsounveiled two new mechanisms, the effect of free surfaces and “unzipping”.Both mechanisms may be relevant to natural materials such as nacre orbone.

Porous silicon waveguides with integrated porous silicon grating couplersare demonstrated as small molecule biosensors. Two fabrication methods arepresented for the grating couplers: standard electron beam lithography withreactive ion etching and a new technique based on direct imprinting ofporous substrates. Although the gratings fabricated using standardlithographic techniques have steeper sidewalls and enable a larger availablesensing surface area inside the waveguide, the imprinted gratings have theadvantage of rapid and low-cost fabrication. Both the lithographically andimprinted sensors are shown to have waveguide losses on the order of 10dB/cm, and both are demonstrated for detection of 16mer nucleic acids.