Room-Temperature Fabrication of p-Type SnO Semiconductors Using Ion-Beam-Assisted Deposition.

Over the past decade, SnO has been considered a promising p-type oxide semiconductor. However, achieving high mobility in the fabrication of p-type SnO films is still highly dependent on the post-annealing procedure, which is often used to make SnO, due to its metastable nature, readily convertible to SnO and/or intermediate phases. This paper demonstrates a fully room-temperature fabrication of p-type SnO thin films using ion-beam-assisted deposition.

Enhanced Plasmonic Biosensor Utilizing Paired Antibody and Label-Free FeO Nanoparticles for Highly Sensitive and Selective Detection of Parkinson's -Synuclein in Serum.

Parkinson's disease (PD) is an acute and progressive neurodegenerative disorder, and diagnosis of the disease at its earliest stage is of paramount importance to improve the life expectancy of patients. α-Synuclein (α-syn) is a potential biomarker for the early diagnosis of PD, and there is a great need to develop a biosensing platform that precisely detects α-syn in human body fluids. Herein, we developed a surface plasmon resonance (SPR) biosensor based on the label-free iron oxide nanoparticles (FeO NPs) and paired antibody for the highly sensitive and selective detection of α-syn in serum samples.

Influence of Relative Humidity on Interparticle Capillary Adhesion.

A homemade instrument is designed to directly characterize the adhesion between two rigid polymeric microspheres in the presence of moist air. The tensile load is measured as a function of approach distance at designated relative humidity (RH). The measurement is consistent with our model from the first approximation.

Soft Polymer-Based Technique for Cellular Force Sensing.

Soft polymers have emerged as a vital type of material adopted in biomedical engineering to perform various biomechanical characterisations such as sensing cellular forces. Distinct advantages of these materials used in cellular force sensing include maintaining normal functions of cells, resembling in vivo mechanical characteristics, and adapting to the customised functionality demanded in individual applications. A wide range of techniques has been developed with various designs and fabrication processes for the desired soft polymeric structures, as well as measurement methodologies in sensing cellular forces.

Vascular Adhesion Protein-1 Determines the Cellular Properties of Endometrial Pericytes.

Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible adhesion molecule and a primary amine oxidase involved in immune cell trafficking. Leukocyte extravasation into tissues is mediated by adhesion molecules expressed on endothelial cells and pericytes. Pericytes play a major role in the angiogenesis and vascularization of cycling endometrium.

Ageing modulates human dermal fibroblast contractility: Quantification using nano-biomechanical testing.

Dermal fibroblasts play a key role in maintaining homoeostasis and functionality of the skin. Their contractility plays a role in changes observed during ageing, especially in processes such as wound healing, inflammation, wrinkling and scar tissue formation as well as structural changes on extracellular matrix. Although alternations in skin physiology and morphology have been previously described, there remains a paucity of information about the influence of chronological ageing on dermal fibroblast contractility.

Examining Cell-Cell Interactions in the Kidney Using AFM Single-Cell Force Spectroscopy.

The ability of individual cells to synchronize activity is a basic feature of efficient and appropriate tissue function. Central to this is the physicochemical binding between cells through multiprotein complexes that functionally mediate adhesion. Importantly, the direct connection of physical properties and intercellular signaling is of great importance to certain pathologies including diabetes.

Quantifying cellular mechanics and adhesion in renal tubular injury using single cell force spectroscopy.

Unlabelled: Tubulointerstitial fibrosis represents the major underlying pathology of diabetic nephropathy where loss of cell-to-cell adhesion is a critical step. To date, research has predominantly focussed on the loss of cell surface molecular binding events that include altered protein ligation. In the current study, atomic force microscopy single cell force spectroscopy (AFM-SCFS) was used to quantify changes in cellular stiffness and cell adhesion in TGF-β1 treated kidney cells of the human proximal tubule (HK2).

Cell mechanics in biomedical cavitation.

Studies on the deformation behaviours of cellular entities, such as coated microbubbles and liposomes subject to a cavitation flow, become increasingly important for the advancement of ultrasonic imaging and drug delivery. Numerical simulations for bubble dynamics of ultrasound contrast agents based on the boundary integral method are presented in this work. The effects of the encapsulating shell are estimated by adapting Hoff's model used for thin-shell contrast agents.

A novel collagen gel-based measurement technique for quantitation of cell contraction force.

Cell contraction force plays an important role in wound healing, inflammation,angiogenesis and metastasis. This study describes a novel method to quantify single cell contraction force in vitro using human aortic adventitial fibroblasts embedded in a collagen gel. The technique is based on a depth sensing nano-indentation tester to measure the thickness and elasticity of collagen gels containing stimulated fibroblasts and a microscopy imaging system to estimate the gel area.

Quantitative investigation of calcimimetic R568 on beta cell adhesion and mechanics using AFM single-cell force spectroscopy.

In this study we use a novel approach to quantitatively investigate mechanical and interfacial properties of clonal β-cells using AFM-Single Cell Force Spectroscopy (SCFS). MIN6 cells were incubated for 48 h with 0.5 mM Ca(2+) ± the calcimimetic R568 (1 μM).

Biomimetic three-dimensional microenvironment for controlling stem cell fate.

Stem cell therapy is an emerging technique which is being translated into treatment of degenerated tissues. However, the success of translation relies on the stem cell lineage commitment in the degenerated regions of interest. This commitment is precisely controlled by the stem cell microenvironment.

Calcium-sensing receptor activation increases cell-cell adhesion and β-cell function.

Background/aims: The extracellular calcium-sensing receptor (CaR) is expressed in pancreatic β-cells where it is thought to facilitate cell-to-cell communication and augment insulin secretion. However, it is unknown how CaR activation improves β-cell function.

Methods: Immunocytochemistry and western blotting confirmed the expression of CaR in MIN6 β-cell line.

Gene expression of single human mesenchymal stem cell in response to fluid shear.

Stem cell therapy may rely on delivery and homing through the vascular system to reach the target tissue. An optical tweezer model has been employed to exert different levels of shear stress on a single non-adherent human bone marrow-derived mesenchymal stem cell to simulate physiological flow conditions. A single-cell quantitative polymerase chain reaction analysis showed that collagen type 1, alpha 2 (COL1A2), heat shock 70-kDa protein 1A (HSPA1A) and osteopontin (OPN) are expressed to a detectable level in most of the cells.

Influence of cell and collagen concentration on the cell-matrix mechanical relationship in a corneal stroma wound healing model.

The effect of different collagen and cell concentrations on the mechanical and remodeling behaviors of corneal stroma wound healing models consisting of collagen hydrogels seeded with human corneal fibroblasts during a 25 day culture period were examined. Human corneal fibroblasts were seeded at 1 × 10(5), 3 × 10(5) or 5 × 10(5) cells per hydrogel, and collagen concentrations of 2.5 mg/ml, 3.

Microfluidic systems for biosensing.

In the past two decades, Micro Fluidic Systems (MFS) have emerged as a powerful tool for biosensing, particularly in enriching and purifying molecules and cells in biological samples. Compared with conventional sensing techniques, distinctive advantages of using MFS for biomedicine include ultra-high sensitivity, higher throughput, in-situ monitoring and lower cost. This review aims to summarize the recent advancements in two major types of micro fluidic systems, continuous and discrete MFS, as well as their biomedical applications.

An optical-manipulation technique for cells in physiological flows.

We have developed a technique to manipulate human red blood cells (RBCs) in hydrodynamic flows. This method applies optical tweezers to trap and move microbead-attached RBCs in a liquid medium at various speeds, while it significantly minimizes laser heating and photon-induced stress for normal operation with laser-trapped cells. Computational fluid dynamics is applied to simulate flow-induced shear stress over the cell membrane and to correlate quantitatively the forces with the cell deformations.

Online monitoring of the mechanical behavior of collagen hydrogels: influence of corneal fibroblasts on elastic modulus.

Collagen hydrogels have been widely used to model biological systems and examine cell behavior in vitro. Of increasing interest is how cells affect the mechanical characteristics of their surrounding matrix and vice versa over long culture periods. In this study, the change in mechanical properties of collagen hydrogels embedded with human corneal fibroblasts was examined over a 6-week culture period using a novel online spherical indentation system.

Mechanical characterization of biomimetic membranes by micro-shaft poking.

The popularity of biomimetic membranes has recently increased due to their biomedical applications such as tissue engineering/regenerative medicine and biosensors. Characterization of the viscoelastic properties of these membranes is important in developing functional membranes. A new micro-shaft poking technique has been developed, which is free from the complication of substrate backing, and which is normally an intractable problem in conventional indentation testing of membrane materials.

Human red blood cells deformed under thermal fluid flow.

The flow-induced mechanical deformation of a human red blood cell (RBC) during thermal transition between room temperature and 42.0 degrees C is interrogated by laser tweezer experiments. Based on the experimental geometry of the deformed RBC, the surface stresses are determined with the aid of computational fluid dynamics simulation.

Optical tweezers for single cells.

Optical tweezers (OT) have emerged as an essential tool for manipulating single biological cells and performing sophisticated biophysical/biomechanical characterizations. Distinct advantages of using tweezers for these characterizations include non-contact force for cell manipulation, force resolution as accurate as 100aN and amiability to liquid medium environments. Their wide range of applications, such as transporting foreign materials into single cells, delivering cells to specific locations and sorting cells in microfluidic systems, are reviewed in this article.

An indentation technique to characterize the mechanical and viscoelastic properties of human and porcine corneas.

Cornea is a load-bearing tissue whose mechanical and viscoelastic characteristics are not well understood, due to the challenge associated with most of the measurements. A novel indentation technique has been developed for mechanical characterization of human and porcine corneal tissue, using a tailored depth-sensing microindentation instrument. During indentation, the corneas were suspended by clamping the edges of the cornea, thus allowing depth-sensing measurement free from the complication of the backing substrate.

A novel optical coherence tomography-based micro-indentation technique for mechanical characterization of hydrogels.

Depth-sensing micro-indentation has been well recognized as a powerful tool for characterizing mechanical properties of solid materials due to its non-destructive approach. Based on the depth-sensing principle, we have developed a new indentation method combined with a high-resolution imaging technique, optical coherence tomography, which can accurately measure the deformation of hydrogels under a spherical indenter at constant force. The Hertz contact theory has been applied for quantitatively correlating the indentation force and the deformation with the mechanical properties of the materials.

The deformation of an erythrocyte under the radiation pressure by optical stretch.

In this paper, the mechanical properties of erythrocytes were studied numerically based upon the mechanical model originally developed by Pamplona and Calladine (ASME J. Biomech. Eng.

Characterizing the viscoelastic properties of thin hydrogel-based constructs for tissue engineering applications.

We present a novel indentation method for characterizing the viscoelastic properties of alginate and agarose hydrogel based constructs, which are often used as a model system of soft biological tissues. A sensitive long working distance microscope was used for measuring the time-dependent deformation of the thin circular hydrogel membranes under a constant load. The deformation of the constructs was measured laterally.