Independent and grouped 3D cell rotation in a microfluidic device for bioimaging applications.

Cell rotation reveals important information which facilitates identification and characterization of different cells. Markedly, achieving three dimensional (3D) rolling rotation of single cells within a larger group of cells is rare among existing cell rotation techniques. In this work we present a simple biochip which can be used to trap and rotate a single cell, or to rotate multiple cells relative to each other within a group of individual red blood cells (RBCs), which is crucial for imaging cells in 3D.

Nanophotonic-Carbohydrate Lab-on-a-Microneedle for Rapid Detection of Human Cystatin C in Finger-Prick Blood.

Miniaturized total analysis systems, for the rapid detection of disease biomarkers, with features including high biomarker sensitivity, selectivity, biocompatibility, and disposability, all at low cost are of profound importance in the healthcare sector. Within this frame of reference, we developed a lab-on-a-carbohydrate-microneedle biodevice by integrating localized surface plasmon resonance (LSPR) paper-based substrates with biocompatible microneedles of high aspect ratio (>60:1 length:width). These microneedles are completely fabricated with carbohydrate (maltose) and further coated with poly lactic--glycolic acid (PLGA), which together serves the purpose of fluid channels.

Biosensor based on ultrasmall MoS2 nanoparticles for electrochemical detection of H2O2 released by cells at the nanomolar level.

Monodispersed surfactant-free MoS2 nanoparticles with sizes of less than 2 nm were prepared from bulk MoS2 by simple ultrasonication and gradient centrifugation. The ultrasmall MoS2 nanoparticles expose a large fraction of edge sites, along with their high surface area, which lead to attractive electrocatalytic activity for reduction of H2O2. An extremely sensitive H2O2 biosensor based on MoS2 nanoparticles with a real determination limit as low as 2.

The role of enamel proteins in protecting mature human enamel against acidic environments: a double layer force spectroscopy study.

Characterisation of the electrostatic properties of dental enamel is important for understanding the interfacial processes that occur on a tooth surface and how these relate to the natural ability of our teeth to withstand chemical attack from the acids in many soft drinks. Whereas, the role of the mineral component of the tooth enamel in providing this resistance to acid erosion has been studied extensively, the influence of proteins that are also present within the structure is not well understood. In this paper, we report for the first time the use of double-layer force spectroscopy to directly measure electrostatic forces on as received and hydrazine-treated (deproteinated) enamel surfaces in solutions with different pH to determine how the enamel proteins influence acid erosion surface potential and surface charge of human dental enamel.

Controllable selective exfoliation of high-quality graphene nanosheets and nanodots by ionic liquid assisted grinding.

Bulk quantities of graphene nanosheets and nanodots have been selectively fabricated by mechanical grinding exfoliation of natural graphite in a small quantity of ionic liquids. The resulting graphene sheets and dots are solvent free with low levels of naturally absorbed oxygen, inherited from the starting graphite. The sheets are only two to five layers thick.

Hydrodynamic methods for calibrating the normal spring constant of microcantilevers.

Knowledge of the spring constants of microcantilevers is vital in atomic force microscopy and for cantilever-based devices that are, for example, employed as probes in biomedical applications. We compare two recently developed hydrodynamic methods for the determination of the normal spring constant of microcantilevers. Both approaches are non-invasive when determining the spring constant and require only knowledge of the thermal noise response of the cantilever in a fluid and its plan view dimensions.

Calibration of the normal spring constant of microcantilevers in a parallel fluid flow.

We demonstrate a novel approach to determine the normal spring constant of microcantilevers. The cantilevers are placed parallel to a fluid flow thus establishing one of the walls of the flow channel. Resonance frequencies are recorded depending on the velocity of the fluid.

Particle-surface capillary forces with disjoining pressure.

A new, atomic force microscopy (AFM) based experimental setup for the continuous acquisition of friction force data as a function of humidity has been developed. The current model of interactions between wet contacts under the influence of capillary effects, has been amended to include a vertical component due to the disjoining pressure and takes into account the influence of liquid films adsorbed on the surface. This is a 'switching' model, i.