Nanoarchitectonics in immobilization of DNT/TNT specific binding peptides on laser-induced graphene

Abstract

Bio/chemical sensors require high selectivity for specific targets. Carbon nanomaterials, especially graphene-based materials, are preferred in sensors due to their high surface area, superior electrical conductivity, mechanical strength, and flexibility. In this study, DNT-bp (Dinitrotoluene binding peptide) and TNT-bp (Trinitrotoluene binding peptide) were immobilized on LIG (Laser-induced graphene) films through covalent and non-covalent interactions. EDC (1-ethyl-3-3-dimethylaminopropyl carbodiimide hydrochloride) is used to activate carboxylic acid groups, which then react with NHS (N-hydroxysuccinimide) to form NHS esters, facilitating the binding of amine-containing peptides to the LIG surface. XPS analysis of LIG films functionalized with EDC+NHS shows a decrease in COOH (carboxyl) and an increase in C-N/C=N/C-O groups. N1s peak at high-resolution XPS spectrum indicates that DNT-bp immobilization leads to higher elimination of NHS-esters, resulting in fewer N-C=O (amide) functional groups and more protonated nitrogen, which suggests that DNT-bp immobilization is more effective than TNT-bp immobilization. The findings suggest that LIG-based sensors provide a cost-effective platform for the detection of DNT (2,4-dinitrotoluene) and 2,4,6-trinitrotoluene (TNT). Further advancements in LIG-based biosensors may enable their broader application in security, environmental monitoring, and health diagnostics.