Investigation of Acetone Vapour Sensing Properties of a Ternary Composite of Doped Polyaniline, Reduced Graphene Oxide and Chitosan Using Surface Plasmon Resonance Biosensor.

This work reports the use of a ternary composite that integrates p-Toluene sulfonic acid doped polyaniline (PANI), chitosan, and reduced graphene oxide (RGO) as the active sensing layer of a surface plasmon resonance (SPR) sensor. The SPR sensor is intended for application in the non-invasive monitoring and screening of diabetes through the detection of low concentrations of acetone vapour of less than or equal to 5 ppm, which falls within the range of breath acetone concentration in diabetic patients. The ternary composite film was spin-coated on a 50-nm-thick gold layer at 6000 rpm for 30 s.

Acetone Vapor-Sensing Properties of Chitosan-Polyethylene Glycol Using Surface Plasmon Resonance Technique.

To non-invasively monitor and screen for diabetes in patients, there is need to detect low concentration of acetone vapor in the range from 1.8 ppm to 5 ppm, which is the concentration range of acetone vapor in diabetic patients. This work presents an investigation for the utilization of chitosan-polyethylene glycol (PEG)-based surface plasmon resonance (SPR) sensor in the detection of trace concentration acetone vapor in the range of breath acetone in diabetic subjects.

Green's function for a sharpened and metal-coated dielectric probe.

In apertureless scanning-probe optical microscopy and in the case of more traditional scanned optical probes coated with a metal that is thin near the probe tip (in lieu of an aperture), samples are probed via interaction between the probe and surface. In the nanometer-scale region between the tip and the sample, the field can be approximated by quasi-electrostatic analytics. Hence, the coated probe can be modeled as in the present case as a hyperboloid of revolution without the need for hyperboloidal wave functions in the near zone.

Dynamic microcantilever sensors for discerning biomolecular interactions.

Response of a conductive micromechanical cantilever placed in close proximity to a surface undergoing electrical excitation near the resonance frequency of the cantilever is influenced by the presence of microscopic dielectrics in the gap between the cantilever and the sample surface. The variations of the resonance response of unmodified cantilevers at gap distances below a few hundred nanometers are used to discern biomolecular differences of oligomeric nucleic acids in an array format without the use of extrinsic labels. The resonance response variation paves the way for the development of high throughput detection of biomolecular reactions, such as DNA hybridization reactions or antibody-antigen interactions without the use of external labels, in which the need is only to see the presence or absence of interaction.