Blu-Ray Discs as Universal Biochip Substrates: Lithography-Free Surface Activation and Assay Patterning

Area of Science:

• Materials Science
• Biotechnology
• Surface Chemistry

Background:

• Blu-ray discs (BDs) possess high-quality materials suitable for advanced applications.
• The "Hard Coat" film on Verbatim BDs presents a unique polymeric substrate.
• Existing biochip substrates often require complex fabrication methods.

Purpose of the Study:

• To investigate the potential of Blu-ray disc Hard Coat film as a substrate for biochip fabrication.
• To develop a simple and effective method for activating and functionalizing the BD substrate.
• To demonstrate the utility of BD-based biochips in quantitative assays.

Main Methods:

• Chemical activation of the Hard Coat film using a sodium hydroxide (NaOH) solution.
• Surface characterization to determine the density of generated carboxylic acid groups.
• Lithography-free patterning using filter paper masks and microfluidic channel plates.
• Demonstration of biochip functionality using biotin-streptavidin binding and DNA hybridization assays.

Main Results:

• The activated BD substrate exhibits a high surface density of carboxylic acid groups (6.6 ± 0.7 × 10^-9 mol/cm²).
• Activation involves treatment with 1.0 M NaOH at 55 °C, yielding an optically transparent, low-fluorescence surface.
• Lithography-free patterning methods were successfully employed for device fabrication.
• Quantitative assays using biotin-streptavidin and DNA hybridization demonstrated the substrate's efficacy.

Conclusions:

• Blu-ray disc Hard Coat film is a promising, cost-effective, and easily adaptable substrate for biochip development.
• The chemical activation method provides a high density of reactive sites without damaging the substrate.
• Lithography-free patterning facilitates accessible biochip fabrication in standard laboratory settings.
• BD-based biochips are suitable for sensitive and quantitative biological assays.