Electron donating group substituted and α-d-mannopyranoside directly functionalized polydiacetylenes as a simplified bio-sensing system for detection of lectin and E. coli

Non-lipid and β-d-glucopyranoside, β-d-galactopyranoside and α-d-mannopyranoside directly functionalized polydiacetylenes were modified by using methylphenyl as electron donating groups to investigate their optical properties and detection ability in the presence of lectin and Escherichia coli. Direct functionalization of sugar molecule provided a much simplified and rapid platform for lectin and E. coli detection as the incorporation of two or more components was not required. The results showed that the polymerization was possible by attaching methylphenyl as an electron donating group in polydiacetylene formation instead of a long alkyl group. After UV irradiation, a yellow solution was obtained and the molecular weight of this system was 80,500 ± 500 g/mol. Concentration-dependant quenching experiments demonstrated that only α-d-mannopyranoside functionalized polydiacetylene showed significant quenching with Concanavalin A (Con A) and E. coli. However, no colour change could be observed during Con A and bacteria detection. Polydiacetylene has a much better quenching effect if compared with the respective monomeric form. Hysteresis studies were performed which confirmed that this system could be used as a simplified biosensor for bacteria detection. This α-d-mannopyranoside functionalized polydiacetylene with electron donating group of methylphenyl developed in this study has future potentials for the development of simple and rapid biosensors.