We report the design, construction, and testing of a contact lens with an integrated amperometric glucose sensor, proposing the possibility of in situ human health monitoring simply by wearing a contact lens. The glucose sensor was constructed by creating microstructures on a polymer substrate, which was subsequently shaped into a contact lens. Titania sol-gel film was applied to immobilize glucose oxidase, and Nafion® was used to decrease several potential interferences (ascorbic acid, lactate, and urea) present in the tear film. The sensor exhibits a fast response (20 sec), a high sensitivity (240 µAcm −2 mM −1 ) and a good reproducibility after testing a number of sensors. It shows good linearity for the typical range of glucose concentrations in the tear film (0.1-0.6 mM), and acceptable accuracy in the presence of interfering agents. The sensor can attain a minimum detection of less than 0.01 mM glucose.

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We present an integrated functional contact lens, composed of a differential glucose sensor module, metal interconnects, sensor read-out circuit, antenna and telecommunication circuit, to monitor tear glucose levels wirelessly, continuously and non-invasively. The electrochemical differential sensor module is based on immobilization of activated and de-activated glucose oxidase. We characterized the sensor on a model polymer eye and determined that it showed good repeatability, molecular interference rejection and linearity in the range of 0–2 mM glucose, covering normal tear glucose concentrations (0.1–0.6 mM). We also report the temperature, ageing and protein-fouling sensitivity of the sensor. We report the design and implementation of a low-power (3 µW) sensor read-out and telecommunication circuit to deliver wireless power and transmit data for the sensor module. Using this small chip (0.36 mm2), we produced an integrated contact lens with sensors and demonstrated wireless operation of the system and glucose read-out over the distance of several centimeters.

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The assembly and characterization of gold nanoparticle-based binary and ternary structures are reported. Two strategies were used to assemble gold nanoparticles into ordered nanoscale architectures: in strategy 1, gold nanoparticles were functionalized with single-strand DNA (ssDNA) first, and then hybridized with complementary ssDNA-labelled nanoparticles to assemble designed architectures. In strategy 2, the designed architectures were constructed through hybridization between complementary ssDNA first, then by assembling gold nanoparticles to the scaffolding through gold–sulfur bonds. Both TEM measurements and agarose gel electrophoresis confirmed that the latter strategy is more efficient in generating the designed nanostructures.

Angiogenesis requires endothelial cell invasion and is crucial for wound healing and for tumor growth and metastasis. Invasion of native collagen is mediated by the alpha(5)beta(1) integrin fibronectin receptor. Thus, alpha(5)beta(1) up-regulation on the surfaces of endothelial cells may induce endothelial cell invasion to stimulate angiogenesis. We report that the interaction of alpha(5)beta(1) with its PHSRN peptide ligand induces human microvascular endothelial cell invasion and that PHSRN-induced endothelial cell invasion is regulated by alpha(4)beta(1) integrin and requires matrix metalloproteinase 1 (MMP-1). Moreover, our results show that exposure to PHSRN causes rapid, specific up-regulation of surface levels of alpha(5)beta(1) integrin and significantly increases alpha(5) integrin mRNA in microvascular endothelial cells. Consistent with these results, alpha(5) small interfering RNA abrogates PHSRN-induced surface alpha(5) and MMP-1 up-regulation, as well as blocking invasion induction. We also observed dose-dependent, PHSRN-induced alpha(5)beta(1) integrin up-regulation on endothelial cells in vivo in Matrigel plugs. We further report that the PHSCN peptide, an alpha(5)beta(1)-targeted invasion inhibitor, blocks PHSRN-induced invasion, alpha(5)beta(1) up-regulation, alpha(5) mRNA induction, and MMP-1 secretion in microvascular endothelial cells and that systemic PHSCN administration prevents PHSRN-induced alpha(5)beta(1) up-regulation and angiogenesis in Matrigel plugs. These results demonstrate a critical role for alpha(5)beta(1) integrin and MMP-1 in mediating the endothelial cell invasion and angiogenesis and suggest that PHSRN-induced alpha(5) transcription and alpha(5)beta(1) up-regulation may form an important feed-forward mechanism for stimulating angiogenesis.

BackgroundThe great advances of nanomaterials have brought out broad important applications, but their possible nanotoxicity and risks have not been fully understood. It is confirmed that exposure of environmental particulate matter (PM), especially ultrafine PM, are responsible for many lung function impairment and exacerbation of pre-existing lung diseases. However, the adverse effect of nanoparticles on allergic asthma is seldom investigated and the mechanism remains undefined. For the first time, this work investigates the relationship between allergic asthma and nanosized silicon dioxide (nano-SiO2).Methodology/Principal FindingsOvalbumin (OVA)-treated and saline-treated control rats were daily intratracheally administered 0.1 ml of 0, 40 and 80 µg/ml nano-SiO2 solutions, respectively for 30 days. Increased nano-SiO2 exposure results in adverse changes on inspiratory and expiratory resistance (Ri and Re), but shows insignificant effect on rat lung dynamic compliance (Cldyn). Lung histological observation reveals obvious airway remodeling in 80 µg/ml nano-SiO2-introduced saline and OVA groups, but the latter is worse. Additionally, increased nano-SiO2 exposure also leads to more severe inflammation. With increasing nano-SiO2 exposure, IL-4 in lung homogenate increases and IFN-γ shows a reverse but insignificant change. Moreover, at a same nano-SiO2 exposure concentration, OVA-treated rats exhibit higher (significant) IL-4 and lower (not significant) IFN-γ compared with the saline-treated rats. The percentages of eosinophil display an unexpected result, in which higher exposure results lower eosinophil percentages.Conclusions/SignificanceThis was a preliminary study which for the first time involved the effect of nano-SiO2 to OVA induced rat asthma model. The results suggested that intratracheal administration of nano-SiO2 could lead to the airway hyperresponsiveness (AHR) and the airway remolding with or without OVA immunization. This occurrence may be due to the Th1/Th2 cytokine imbalance accelerated by the nano-SiO2 through increasing the tissue IL-4 production.

Silicon nanowires ͑SiNWs͒ were investigated as supporting matrices for enzyme immobilization to construct glucose biosensors. Glucose oxidase was adsorbed onto SiNWs after different treatments, either as grown, HF etched, or carboxylic acid ͑COOH͒ functionalized. The amperometric biosensor with COOH-functionalized SiNWs performed the best with a detection limit of 0.01 mM glucose ͑signal-to-noise ratio= 3͒. For real-time detection of glucose, SiNW biosensor showed a linear response in the range of 0.1-15 mM. This work demonstrates the utility of SiNWs as a biosensor component and provides a general method to modify the surface of semiconducting nanomaterials for potential biomedical applications.