Next-Generation Wound Care: Aptamer-Conjugated Polydiacetylene/Polyurethane Nanofibrous Biosensors for Selective In Situ Colorimetric Detection of Pseudomonas

Abstract

Biosensors for wound dressings can enable point-of-care monitoring of wound bed health by exhibiting a color change visible to the naked eye, to alert healthcare providers of the presence of pathogenic bacteria. Here, a polydiacetylene-based electrospun nanofibrous wound dressing for the detection of Pseudomonas aeruginosa is reported. Using conventional blend electrospinning, two diacetylene monomers—10,12-pentacosadiynoic acid (PCDA) and 10,12-tricosadiynoic acid (TCDA)—are separately electrospun alongside polyurethane as a supporting matrix polymer. The differences in side-chain length impact the sensitivity of the nanofibers in detecting P. aeruginosa. Furthermore, two DNA aptamers are conjugated to the polydiacetylenes to achieve targeted detection of P. aeruginosa. The aptamer-modified dressings show improved sensitivity of detection toward eight strains of P. aeruginosa compared to the unmodified membranes. Furthermore, the aptamer-modified membranes do not respond to non-target bacteria methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, and Escherichia coli within 3 h of direct contact. Reducing the chain-length of the diacetylene monomer by substituting PCDA with TCDA boosts the colorimetric response by a factor of >2x compared to the aptamer-modified PCDA membranes, at the cost of reduced specificity. The aptamer-conjugated polydiacetylene membranes show promise for application in point-of-care wound dressings for improved specificity of detection of bacterial infections.