Detecting Attomolar Concentrations of Interleukin IL-17A via Pollen-Based Nanoplasmonic Biochips

Interleukins are involved in several diseases and cancers, and their detection and monitoring are of great interest. Their low abundance and short half-lives suggest the need to develop rapid, specific, and highly sensitive detection platforms, easily integrable in point-of-care (POC) systems. Among the other interleukins, interleukin IL-17A is associated with inflammations, neurodegenerative diseases, and cancers, and no biosensors have been previously reported for its detection. In this work, for the detection of IL-17A, a highly sensitive nanoplasmonic sensor based on natural nanostructures like pollen shells, covered by a gold film and a bio-receptor layer, is presented. Hybrid plasmonic modes are exploited to reach high sensitivity without using costly techniques to fabricate periodic nanostructures, such as electron beam lithography. A transparent amino-modified glass substrate is functionalized with carboxylic activated pollen via carbodiimide chemistry. Then, the pollen-based nanostructures are covered by a gold film and derivatized by an immuno-layer specific to IL-17A recognition. The developed IL-17A biosensor is monitored via a simple, small-sized, and low-cost experimental setup, demonstrating high selectivity, a fast response time of about five minutes, and sensitivity with a limit of detection in the ag/mL concentration range. The biosensor allows for the detection of IL-17A in complex solutions thanks to the possibility of high dilution, an advantageous aspect to POC systems.