- Quantifying Lipid Contents in Enveloped Virus Particles with Plasmonic Nanoparticles
Phosphatidylserine (PS) and monosialotetrahexosylganglioside (GM1) are examples of two host-derived lipids in the membrane of enveloped virus particles that are known to contribute to virus attachment, uptake, and ultimately dissemination. A quantitative characterization of their contribution to the functionality of the virus requires information about their relative concentrations in the viral membrane. We introduce herein a gold nanoparticle (NP) binding assay for probing relative PS and GM1 lipid concentrations in the outer leaflet of different virus-like particles (VLPs) using sample sizes of less than 3×106 particles. The assay evaluates both scattering intensity and resonance wavelength and determines relative NP densities through plasmon coupling as a measure for the target lipid concentrations in the NP-labeled VLP membrane. A correlation of the optical observables with absolute lipid contents was achieved by calibration of the plasmon coupling-based methodology with unilamellar liposomes of known PS or GM1 concentration. The performed studies reveal significant differences in the membrane of VLPs that assemble at different intracellular sites and pave the way to an optical quantification of lipid concentration in virus particles at physiological titers.
Optimizing the performance of electrochemical biosensors using a continuous system of fabrication and qualifying the best combination of different strip variables
Abstract: The possibility of making some improvements in the overall structure of the electrochemical portable biosensors to reduce the amount of their error and obtain a higher performance was investigated. Glucose biosensor was chosen as a case study, because it is now commercially produced and widely used, so the results of this study can be compared with a reliable source. This optimizing process was performed by designing and manufacturing a new complex of systems for producing the biosensor test strips, using novel methods such as inkjet printing of conductive electrodes and enzyme solution. Also, the design of the electrical circuits and digital monitoring system was developed.
This project resulted in registering some patents on a digital monitor for showing the concentration of different analytes in blood, capable of working with all available commercial test strips and an optimized semi-industrial production line for biosensor test strips.
Producing a carbon monoxide sensor based on PEDOT-PSS as a conductive polymer
Abstract: Poly (3,4-ethylenedioxy) thiophene–poly (styrenesulfonate) has been used as a base to produce a carbon monoxide chemiresistive detector. Poly (3,4-ethylenedioxy) thiophene/poly (styrenesulfonate) (PEDOT/PSS) thin films were prepared by spin coating method. The polymer was tested by some common gases in the atmosphere to determine its discrimination ability to detect CO. Particular impositions of Fe, Al and morpholine were also added to the polymer solution to improve thin films sensitivity (percent of resistance variations with respect to its initial value) to recognize carbon monoxide from other gases like water vapor. Room air contains a partial pressure of water vapor which has the main effect on pure polymer. As doping agents were added to the polymer, prepared thin films showed a satisfying sensitivity to CO which was now comparable with the effects of room air. The sensor behavior in approach to room air and carbon monoxide and also the effect of dopants on the polymer has been described. (Results were published here.)