Comparison of DNA Analysis on Biochips with Brush Polymer Cells and Cross-Linked Polymer Cells

Objective: The regulation of substrate surface properties in biochip technology opens the possibility of optimizing platforms for efficient biomolecule recognition. The research aims to explore the potential of using brush polymers to improve the sensitivity and speed of DNA analysis on biochips. Methods: Brush polymer cells for biochips were prepared by UV-initiated polymerization of monomers from the surface on polyethylene terephthalate substrates. Cross-linked hydrogel polymer cells for biochips were prepared on polybutylene terephthalate substrates by copolymerization of gel components with DNA probes. The probes in brush polymer cells were immobilized through activated carboxyl groups. A 124 nucleotides long DNA target corresponding to the 7th exon of the human ABO gene was used for hybridization analysis. Hybridization of the target DNA was studied on biochips with cells made of brush polymers and cross-linked polyacrylamide hydrogels. The results were evaluated by digital fluorescence microscopy. Results and Discussion: Higher intensity of fluorescence signals and higher ratio of signals of cells with perfect duplexes to those of cells with imperfect duplexes were observed in cells made of brush polymers compared to cells made of three-dimensional cross-linked polymers. Achievement of hybridization signal up to 90% of saturation occurred at the same time in both cell types. Conclusions: Hybridization analysis on brush polymer cells in biochip technology showed increased sensitivity in detecting single nucleotide mutations.