Abstract

Photochemical Generation of Biofunctionalized Micro Sponges Via Two Phase Flow for Lab-on-a-Chip Applications

Thomas Brandstetter, Group Leader, Freiburg University

Biofunctional particles typically require multistep synthetic procedures to link biomolecules to particles. Moreover, the introduced binding sites are only at the particle’s surface, whereas their inner bulk isn’t accessible. Our approach provides cryogelparticles, whose complete volume are equipped with biomolecules, while being easily accessible via micropores. Thereby, increased sensitivity was demonstrated by e.g. enrichment and subsequent PCR amplification of viral DNA. The dramatic acceleration of binding kinetics was shown on the protein-level with streptavidin. In two model applications, these cryogelparticles were either employed as free particles or as mobile pseudo-liquid supports inside fluidic chips. The fabrication envisions microfluidic generation of aqueous plugs containing photopolymer and biomolecules. These plugs are frozen and illuminated. During freezing, microphase separation occurs and systems consisting of crystallized water and an unfrozen polymer solution called ’liquid microphase’ (LMP), are obtained. Upon UV-exposure, the polymers in the LMP crosslink and any biofunctional molecule present in this solution, is covalently attached to the forming gel. After thawing a spongelike network of interconnected pores remains. Thus, within one single reaction step, a ready-to-use, biofunctional and transparent particle is produced for capture and release of rare targets within the potential of a huge impact on Lab-on-a-Chip Technologies.