Liquid crystal-based glucose biosensor functionalized with mixed PAA and QP4VP brushes.

Area of Science:

• Materials Science
• Biotechnology
• Analytical Chemistry

Background:

• Development of sensitive and cost-effective glucose biosensors is crucial for diabetes management.
• Existing methods often require complex enzyme immobilization or lack stability.
• Liquid crystal polymers (LCPs) offer unique optical properties for sensing applications.

Purpose of the Study:

• To develop a novel glucose biosensor using a transmission electron microscopy (TEM) grid.
• To functionalize the TEM grid with dual polymer brushes for enzyme immobilization and pH responsiveness.
• To evaluate the sensor's sensitivity, response time, and stability for glucose detection.

Main Methods:

• Coating a TEM grid with poly(acrylic acid-b-LCP) and quaternized poly(4-vinylpyridine-b-LCP) brushes.
• Immobilizing glucose oxidase (GOx) onto the functionalized TEM grid via electrostatic interactions.
• Detecting glucose through the orientational transition of 4-cyano-4'-pentylbiphenyl (5CB) observed via polarized optical microscopy (POM).

Main Results:

• The dual-brush-coated TEM grid successfully immobilized GOx.
• The biosensor detected glucose concentrations above 0.5 mM with response times under 180 seconds.
• A linear response of 5CB birefringence to glucose (0.5–11 mM) was observed, with a Michaelis-Menten constant (Km) of 1.67 mM.

Conclusions:

• The developed TEM grid glucose biosensor is sensitive, stable, and cost-effective.
• Simple enzyme immobilization and easy detection via POM are key advantages.
• This biosensor shows potential for prescreening glucose levels in the human body.