Functionalization of poly(methyl methacrylate) (PMMA) as a substrate for DNA microarrays

Area of Science:

• Materials Science
• Biotechnology
• Surface Chemistry

Background:

• Poly(methyl methacrylate) (PMMA) is a versatile polymer for microfluidic devices.
• Immobilizing DNA on surfaces is crucial for microarray-based diagnostics.
• Existing PMMA surface modifications may not be optimal for DNA immobilization.

Purpose of the Study:

• To develop a chemical procedure for functionalizing PMMA substrates.
• To create an aminated surface on PMMA for efficient DNA probe immobilization.
• To evaluate the performance of aminated PMMA slides for DNA microarrays.

Main Methods:

• PMMA substrates were reacted with hexamethylene diamine to introduce primary amine groups.
• DNA probes were immobilized onto the aminated PMMA surface.
• Hybridization efficiency was assessed using complementary DNA strands.
• Thermal stability was tested by subjecting microarrays to Polymerase Chain Reaction (PCR) heat cycles.

Main Results:

• A surface density of 0.29 nmol/cm2 of primary amine groups was achieved.
• Successful immobilization of DNA probes and hybridization with complementary strands was confirmed.
• Hybridization signal and efficiency were comparable to other modified surfaces, including silanized glass.
• Immobilized probe density reached 10 pmol/cm2, with a hybridized density of 0.75 pmol/cm2.
• Immobilized probes exhibited excellent heat stability, with only a 4% reduction in performance after 20 PCR heat cycles.

Conclusions:

• A robust chemical strategy was established to functionalize PMMA for DNA immobilization.
• Aminated PMMA serves as a highly effective substrate for DNA microarrays.
• This method supports the fabrication of single-use diagnostic devices with integrated functions.