Prof. Soumyo Mukherji and his team at Department of Biosciences and Bioengineering
have developed a rapid and simple
process for activation of epoxy surfaces such as SU-8 (Glycidyl ether of
bisphenol A), to enable surface immobilization
of molecules with carboxyl and / or amino functional groups.
Microsystems for biological applications require immobilization of biological
molecules within the device.
Conventionally, substrate materials used for these devices have been silicon
and noble metals (e.g. gold) which have
been found to have shortcomings in terms of their high Young's modulus,
biocompatibility and their suitability for micro
fabrication. Immobilization of bio-molecules onto epoxy surfaces such as
SU-8 is of interest because of their application
in surface modification, bioMEMS, biomolecule immobilization related assays,
biosensors, membrane bioreactors, clinical
diagnostics, molecular biology, agriculture, environmental science and
chemical / biochemical industry.
Bare SU-8 patterned with conventional photolithography techniques
does not allow the immobilization of antibodies on
its surface. Several methods are known for the modifications of polymer
surfaces are not suitable for SU8 surface modification.
The process of the invention developed at IIT Bombay involves grafting
of NH2+ groups on the epoxy (e.g.
SU-8) surface using hotwire induced pyrolytic decomposition of ammonia
under vacuum, followed by antibody immobilization
on the treated SU-8 surface. The process of the invention enables single
or multi-step tailored immobilization
of biomolecules (antigen, antibodies, proteins, DNA, RNA enzymes etc.)
on the modified epoxy surface.
Indian patent application no. 1267/MUM/2004 Patent grant no. 213504
Inventors: S Mukherji, R O Dusane, R Lal and V R Rao, N Kale and M Joshi, students of EE/SBB