DNA Detection on Plastic:  Surface Activation Protocol To Convert Polycarbonate Substrates to Biochip Platforms

Abstract

A mild and efficient surface activation protocol to convert polycarbonate (PC) substrates, e.g., plastic bases of compact disks, to biochip platforms for DNA probe immobilization and target detection is described. The preparation procedure (activation, patterning, and coupling) is simple and effective; the on-chip hybridization is sensitive and selective. Particularly, UV/ozone treatment of PC sheets produces a hydrophilic surface with a high density of reactive carboxylic acid groups [(4.8 +/- 0.2) x 10-10 mol/cm2] in less than 10 min at ambient conditions, and no significant aging or physical damage to the substrate is observed. Covalent immobilization of DNA probes via both passive (reagent-less photopatterning and coupling in bulk solution phase) and flow-through (creation of microarrays with microfluidic channel plates) procedures has been demonstrated. Subsequent hybridization shows uniform and strong fluorescent signals for complementary target DNA and allows clear discrimination between fully complementary targets and strands with a single base-pair mismatch. The surface chemistry described herein will facilitate the development of disposable plastic biochips (not limited to DNA microarrays) and the fabrication of biomedical devices that are readable with conventional optical drives.

Plastic Polymers for Efficient DNA Microarray Hybridization: Application to Microbiological Diagnostics

“…High background fluorescence on plastic supports is often due to nonspecific adsorption of the labeled target onto the substrate (4,13,19). In the present study, we report high signal-to-background ratios.…”

“…However, the high autofluorescence of standard polymeric materials is not compatible with a highly sensitive detection method that employs fluorescent targets. Plastic microarray hybridizations compatible with fluorescent dyes have been developed previously (5,6,13). However, these investigators reported only hybridizations with labeled oligonucleotides, and the specific hybridization signal-to-background ratios were relatively low.…”

“…However, these investigators reported only hybridizations with labeled oligonucleotides, and the specific hybridization signal-to-background ratios were relatively low. Others have avoided this issue by using nonfluorescent detection technologies such as radiolabeling (13,22) or enzymatic reactions (17), but none of these detection technologies fulfill the diagnostic requirement in terms of both rapidity and safety. In this work, we report ultrasensitive microarray hybridization of fluorescently labeled PCR-amplified target DNA using two high-quality plastic substrates for molecular diagnostic purposes.…”

Robust superhydrophilic patterning of superhydrophobic ormosil surfaces for high-throughput on-chip screening applications

“…7,15 However, contact angle increases on polymer surfaces over time aer the treatment (hydrophobic recovery effect) due to the exibility and reorganization of the bonds within the polymer chains. [36][37][38] Here, we report a facile method for the generation of very stable superhydrophilic/superhydrophobic patterned surfaces. Superhydrophobic surfaces were prepared from nanostructured ormosil nanoparticles synthesized via sol-gel method where hydrophobic surface chemistry and high surface roughness were combined in one-pot approach.…”

Screening methodologies for the determination of water contaminant residues by compact disk technology

“…The strategy is based on hydrophobic interactions between probes and polycarbonate, showing high immobilization yields. 186 Following this research line, Li et al 187 developed bioassays performed directly on a CD in a line array format. The aim was to detect different types of biochemical recognition reactions (biotin-streptavidin binding, DNA hybridization and protein-protein interactions) with standard optical drives.…”