Biomolecular recognition is a fundamental aspect in the biosensor development. The goal is to immobilize the biomolecule probes in an active state, limiting the non specific adsorption and maximizing their binding site accessibility for the bio-recognition of the target molecules. In this manner the sensitivity and the specificity of detection is enhanced by active surface densification of the recognition agents. To fulfill these requirements, the chemical functionalization of the transducer surfaces play an crucial role. An accurate control of the surface physico-chemical properties combined with the nano-structuring of the surfaces is considered as a key aspect for biosensors performance enhancement. Many works are performed worldwide to develop advanced platforms with controlled surface chemistry and well defined nano-patterns. Among the different nano-patterning techniques nano-sphere lithography is a very flexible technology to produce nano-structured and chemically nano-patterned surfaces. Moreover this technique presents the advantage to be inexpensive and enable to produce nano-topography over large area surfaces. In this work, we compare the detection performances of uniformly functionalized surface with chemically nano-patterned surfaces for antigen/antibody interactions. In particular, flat Poly Acrylic acid (PAA), carboxylic functional, was compared with PAA nano-area in anti-fouling matrix, fabricated by combining colloidal lithography, plasma polymerization and etching processes. Chicken Egg Albumin was immobilized on the previously described functionalized and nano-patterned QCM-D quartz resonators surfaces and the immuno-reaction with Monoclonal Anti-Chicken Egg Albumin was monitored online in a E-4 Q-SenseAB system. Nano-patterned surfaces showed a considerable (factor 10) enhancement of the immunoreaction efficiency with respect to the non-structured surfaces. These results are confirmed by classical Elisa experiments. This demonstrates the capability of nano-patterns to improve the binding site accessibility of the immobilized biological probes.
Journal: TechConnect Briefs
Volume: 4, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 4
Published: May 20, 2007
Pages: 586 - 589
Industry sector: Advanced Materials & Manufacturing
Topicss: Advanced Manufacturing, Nanoelectronics