Surface Micro-Patterned Biofunctionalized Hydrogel for Direct Nucleic Acid Hybridization Detection

The present research is focused on the development of a biofunctionalized hydrogel with a surface diffractive micropattern as a label-free biosensing platform. The biosensors described in this paper were fabricated with a holographic recording of polyethylene terephthalate (PET) surface micro-structures, which were then transferred into a hydrogel material. Acrylamide-based hydrogels were obtained with free radical polymerization, and propargyl acrylate was added as a comonomer, which allowed for covalent immobilization of thiolated oligonucleotide probes into the hydrogel network, via thiol-yne photoclick chemistry. The comonomer was shown to significantly contribute to the immobilization of the probes based on fluorescence imaging. Two different immobilization approaches were demonstrated: during or after hydrogel synthesis. The second approach showed better loading capacity of the bioreceptor groups. Diffraction efficiency measurements of hydrogel gratings at 532 nm showed a selective response reaching a limit of detection in the complementary DNA strand of 2.47 mu M. The label-free biosensor as designed could significantly contribute to direct and accurate analysis in medical diagnosis as it is cheap, easy to fabricate, and works without the need for further reagents.

Automated summary

The present research aimed to develop a label-free biosensing platform using a biofunctionalized hydrogel with a surface diffractive micropattern. The biosensors were fabricated by holographic recording of polyethylene terephthalate (PET) surface micro-structures and their transfer into a hydrogel material. Two different immobilization approaches, during or after hydrogel synthesis, were demonstrated with the latter showing better loading capacity of the bioreceptor groups. The label-free biosensor showed selective response with a limit of detection of 2.47 μM for the complementary DNA strand, making it a cheap and easy-to-fabricate tool for medical diagnosis.