Biosensor based on enzyme-catalysed degradation of thin polymer films.
A biosensor based on the enzyme-catalysed dissolution of biodegradable polymer films has been developed. Three polymer-enzyme systems were investigated for use in the sensor: a poly(ester amide), which is degraded by the proteolytic enzyme alpha-chymotrypsin; a dextran hydrogel, which is degraded by dextranase; and poly(trimethylene) succinate, which is degraded by a lipase. Dissolution of the polymer films was monitored by Surface Plasmon Resonance (SPR). The rate of degradation was directly related to enzyme concentration for each polymer/enzyme couple. The poly(ester amide)/alpha-chymotrypsin couple proved to be the most sensitive over a concentration range from 4 x 10(-11) to 4 x 10(-7) mol l(-1) of enzyme. The rate of degradation was shown to be independent of the thickness of the poly(ester amide) films. The dextran hydrogel/dextranase couple was less sensitive than the poly(ester amide)/alpha-chymotrypsin couple but showed greater degradation rates at low enzyme concentrations. Enzyme concentrations as low as 2 x 10(-11) mol l(-1) were detected in less than 20 min. Potential fields of application of such a sensor system are the detection of enzyme concentrations and the construction of disposable enzyme based immunosensors, which employ the polymer-degrading enzyme as an enzyme label.
Sumner
C
C
Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
Krause
S
S
Sabot
A
A
Turner
K
K
McNeil
C J
CJ
D001673:Biodegradation, Environmental; D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D002240:Carbohydrate Sequence; D002918:Chymotrypsin; D003910:Dextranase; D003911:Dextrans / Q000737:chemistry; D008049:Lipase; D008969:Molecular Sequence Data; D011091:Polyesters; D011108:Polymers / Q000737:chemistry; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods
D003911:Dextrans; D011091:Polyesters; D011108:Polymers; D008049:Lipase; D003910:Dextranase; D002918:Chymotrypsin; C117608:alpha-chymotrypsin