Three-dimensional protein microarrays fabricated on reactive microsphere modified COC substrates.

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Analytical Chemistry

Background:

• High-density immobilization of biomolecules is crucial for sensitive biochip development.
• Creating three-dimensional (3D) surface structures enhances biomolecule loading capacity.
• Cyclic olefin copolymer (COC) is a suitable substrate for biochip applications due to its optical properties.

Purpose of the Study:

• To develop a strategy for fabricating a 3D protein chip by attaching polymeric microspheres to a COC substrate.
• To enhance the immobilization density and sensitivity of protein microarrays.
• To create a high-performance polymer-based 3D protein chip.

Main Methods:

• Functionalization of COC surface with epoxy and amine groups via photografting.
• Preparation of monodisperse poly(styrene-alt-maleic anhydride) (PSM) copolymer microspheres using precipitation polymerization.
• Deposition of PSM microspheres onto the modified COC surface to create a 3D texture.
• Immobilization of immunoglobulin G (IgG) and subsequent immunoassay.

Main Results:

• Significant increase in surface roughness from 1.4 nm to 37.1 nm after PSM microsphere deposition.
• High immobilization efficiency of IgG (75.6%) and density (0.255 μg cm⁻²).
• Rapid blocking of the 3D protein microarray within 10 minutes.
• Sensitive detection of target protein with a linear range from 6.25 ng mL⁻¹ to 250 ng mL⁻¹ and a limit of detection of 8.87 ng mL⁻¹.

Conclusions:

• The developed strategy effectively creates a 3D surface structure on COC for high-density biomolecule immobilization.
• The 3D protein chip demonstrates high sensitivity and a wide linear detection range for immunoassays.
• This approach offers a novel method for developing high-performance polymer-based 3D protein chips.