Citation:
Dimitris Kyprianou, Antonio R. Guerreiro, Iva Chianella, Elena V. Piletska,
Steven A. Fowler, Kal Karim, Michael J. Whitcombe, Anthony P.F. Turner, Sergey
A. Piletsky, New reactive polymer for protein immobilisation on sensor surfaces,
Biosensors and Bioelectronics, Volume 24, Issue 5, Selected Papers from the
Tenth World Congress on Biosensors Shangai, China, May 14-16, 2008, 1 January
2009, Pages 1365-1371
Abstract:
Immobilisation of biorecognition elements on transducer surfaces is a key step
in the development of biosensors. The immobilisation needs to be fast, cheap and
most importantly should not affect the biorecognition activity of the
immobilised receptor. A novel protocol for the covalent immobilisation of
biomolecules containing primary amines using an inexpensive and simple polymer
is presented. This tri-dimensional (3D) network leads to a random immobilisation
of antibodies on the polymer and ensures the availability of a high percentage
of antibody binding sites. The reactivity of the polymer is based on the
reaction between primary amines and thioacetal groups included in the polymer
network. These functional groups (thioacetal) do not need any further activation
in order to react with proteins, making it attractive for sensor fabrication.
The novel polymer also contains thiol derivative groups (disulphide groups or
thioethers) that promote self-assembling on a metal transducer surface. For
demonstration purposes the polymer was immobilised on Au Biacore chips. The
resulting polymer layer was characterised using contact angle meter, atomic
force microscopy (AFM) and ellipsometry. A general protocol suitable for the
immobilisation of bovine serum albumin (BSA), enzymes and antibodies such as
polyclonal anti-microcystin-LR antibody and monoclonal anti-prostate specific
antigen (anti-PSA) antibody was then optimised. The affinity characteristics of
developed immunosensors were investigated in reaction with microcystin-LR, and
PSA. The calculated detection limit for analytes depended on the properties of
antibodies. The detection limit for microcystin-LR was 10 ng mL−1 and for PSA
0.01 ng mL−1. The non-specific binding of analytes to synthesised polymers was
very low. The polymer-coated chips were stored for up to 2 months without any
noticeable deterioration in their ability to react with proteins. These findings
make this new polymer very promising for the development of low-cost, easy to
prepare and sensitive biosens