UV crosslinked poly(acrylic acid): a simple method to bio-functionalize electrolyte-gated OFET biosensors

Area of Science:

• Organic electronics
• Biosensing technology
• Surface chemistry

Background:

• Organic field-effect transistors (OFETs) offer potential for low-cost biosensing.
• Functionalizing OFET surfaces is crucial for specific biomolecule detection.
• Existing methods for surface functionalization can be complex or time-consuming.

Purpose of the Study:

• To develop a simple, rapid wet method for carboxyl group introduction onto organic semiconductor surfaces.
• To create a bio-functionalized electrolyte-gated organic FET (EGOFET) platform for sensitive analyte detection.
• To demonstrate selective electronic detection of streptavidin using this platform.

Main Methods:

• Spin-coating of poly(acrylic acid) (pAA) on EGOFETs.
• UV-induced cross-linking of pAA without photo-initiators.
• Anchoring of functionalized phospholipid bilayers via carboxyl-amino group reactions.
• Surface characterization using Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS).
• Evaluation of electronic and sensing performance.

Main Results:

• Successful introduction of carboxyl groups on the EGOFET surface.
• Formation of stable phospholipid bilayers.
• Selective electronic detection of streptavidin.
• Achieved picomolar (pM) detection limits for streptavidin.
• Demonstrated significantly higher sensitivity compared to surface plasmon resonance (SPR) assays.

Conclusions:

• The developed wet method provides an efficient way to create carboxyl-functionalized EGOFETs.
• The EGOFET biosensing platform enables highly sensitive and selective detection of specific biomolecules.
• This approach offers a promising alternative to existing biosensing techniques for various applications.