Selective recognition of glucose by the pH-sensitive polymer incorporated porous honeycomb-patterned polymer film

A new approach for the selective detection of glucose was studied by a biomimetic method using pH-sensitive polymer. For this, the pH-sensitive polymer of polymethacrylic acid (PMAA) and the glucose-selective oxidizing enzyme of glucose oxidase (GOD) were incorporated to the pore-selectively –COOH functionalized film by amide covalent bond. The –COOH functionalized porous film was fabricated by casting of polyimide (PI) solution under humid conditions containing KOH. The GOD selectively oxidizes glucose to produce gluconic acid which acts as an H⁺ source able to stimulate the pH-sensitive polymer. The morphology of pore surface was changed to a rough state by adding glucose due to the coil-to-globule transition of pH-sensitive polymer. The degree of roughness was indicated by the aggregated particle size distribution. This smart film can have potential applications in the field of biosensors for direct H⁺ detection or H⁺ producing materials by enzymatic reactions as a biomimetic system.

Graphical abstract

A biomimetic system for selective glucose detection was developed using a pH-sensitive polymer. A porous film functionalized with –COOH was fabricated, and glucose oxidase (GOD) was covalently bonded with polymethacrylic acid (PMAA). GOD oxidizes glucose to produce gluconic acid, triggering the coil-to-globule transition in PMAA, resulting in surface roughness. This system shows potential for biosensors detecting H⁺ through enzymatic reactions.