A novel enzyme entrapment in SU-8 microfabricated films for glucose micro-biosensors.
The present work investigates the utilisation of the widely used SU-8 photoresist as an immobilisation matrix for glucose oxidase (GOx) for the development of glucose micro-biosensors. The strong advantage of the proposed approach is the simultaneous enzyme entrapment during the microfabrication process within a single step, which is of high importance for the simplification of the BioMEMS procedures. Successful encapsulation of the enzyme GOx in "customised" SU-8 microfabricated structures was achieved through optimisation of the one-step microfabrication process. Although the process involved contact with organic solvents, UV-light exposure, heating for pre- and post-bake and enzyme entrapment in a hard and rigid epoxy resin matrix, the enzyme retained its activity after encapsulation in SU-8. Measurements of the immobilised enzyme's activity inside the SU-8 matrix were carried out using amperometric detection of hydrogen peroxide in a 3-electrode setup. Films without enzyme showed negligible variation in current upon the addition of glucose, as opposed to films with encapsulated enzyme which showed a very clear increase in current. Experiments using films of increased thickness or enzyme concentration, showed a higher response, thus proving that the enzyme remained active not only on the film's surface, but also inside the matrix as well. The proposed enzyme immobilisation in SU-8 films opens up new possibilities for combining BioMEMS with biosensors and organic electronics.
Psoma
Sotiria D
SD
Cranfield University, Cranfield Health, Cranfield, Bedfordshire MK43 0AL, UK. psoma@uowm.gr
van der Wal
Peter D
PD
Frey
Olivier
O
de Rooij
Nicolaas F
NF
Turner
Anthony P F
AP
D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques; D004800:Enzymes, Immobilized; D004852:Epoxy Compounds; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase; D007368:Interferometry; D008855:Microscopy, Electron, Scanning; D055616:Microtechnology; D011108:Polymers; D013499:Surface Properties
D004800:Enzymes, Immobilized; D004852:Epoxy Compounds; D011108:Polymers; C520895:SU-8 compound; D005949:Glucose Oxidase; D005947:Glucose