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Biomedical subjects

Y S Shubin

Publications and source records attributed to Y S Shubin.

4 recordsLinked to original sources
PubMed2004

A portable array biosensor for detecting multiple analytes in complex samples.

The Multi-Analyte Array Biosensor (MAAB) has been developed at the Naval Research Laboratory (NRL) with the goal of simultaneously detecting and identifying multiple target agents in complex samples with minimal user manipulation. This paper will focus on recent improvements in the biochemical and engineering aspects of this instrument. These improvements have enabled the expansion of the repertoire of analytes detected to include Salmonella typhimurium and Listeria monocytogenes, and also expanded the different sample matrices tested. Furthermore, all components of the biochemical assays could be prepared well in advance of sample testing, resulting in a "plug-and-play" methodology. Simultaneous detection of three toxins (ricin, staphylococcal enterotoxin B, and cholera toxin) was demonstrated using a novel fluidics cube module that limits the number of manipulations to only the initial sample loading. This work demonstrates the utility of the MAAB for rapid analysis of complex samples with multianalyte capability, with a minimum of operator manipulations required for either sample preparation or final analysis.

Antibodies↗
PubMed2001

Kinetics of antigen binding to arrays of antibodies in different sized spots.

A fluorescence-based array biosensor has been developed which can measure the binding kinetics of an antigen to an immobilized antibody in real time. A patterned array of antibodies immobilized on the surface of a planar waveguide was used to capture a Cy5-labeled antigen present in a solution that was continuously flowed over the surface. The CCD image of the waveguide was monitored continuously for 25 min. The resulting exponential rise in fluorescence signal was determined by image analysis software and fitted to a reaction-limited kinetics model, giving a kf of 3.6 x 10(5) M(-1) s(-1). Different spot sizes were then patterned on the surface of the waveguide using either a PDMS flow cell or laser exposure, producing width sizes ranging from 80 to 1145 microm. It was demonstrated that under flow conditions, the reduction of spot size did not alter the association rate of the antigen with immobilized antibody; however, as the spot width decreased to < 200 nm, the signal intensity also decreased.

Animals↗
PubMed2001

Design and demonstration of an automated cell-based biosensor.

Cell-based biosensors have the capacity to respond to a wide range of analytes in a physiologically relevant manner and appear well-suited for toxicity monitoring of both known and unknown analytes. One means of acquiring cellular functional information for biosensor applications involves extracellular recording from excitable cells, which can generate noninvasive and long-term measurements. Previous work from our laboratory described a prototype portable system capable of high signal-to-noise extracellular recordings, in spite of deficiencies in thermal control, fluidics handling, and absence of data acquisition (DAQ) capability. The present work describes a cell-based biosensor system that incorporates low noise amplifier and filter boards, a two-stage thermal control system with integrated fluidics and a flexible graphical user interface for DAQ and control implemented on a personal computer. Wherever possible, commercial off-the-shelf components have been utilized for system design and fabrication. The system exhibits input-referred noise levels of 5-10 microV(RMS), such that extracellular potentials exceeding 50-60 microV can be readily resolved. In addition, the biosensor system is capable of automated temperature and fluidics control. Flow rates can range from 0-2.5 ml/min, while the cell recording chamber temperature is maintained within a range of 36-37 degrees C. To demonstrate the capability of this system to resolve small extracellular potentials, recordings from embryonic chick cardiac myocytes have been performed.

Action Potentials↗