Capacitive immunosensor based on grafted Anodic Aluminum Oxide for the detection of matrix metalloproteinase 9 found in chronic wounds

Chronic wounds impose a significant burden on healthcare resources, society and more specifically on patients. Preliminary research showed that as of today, there is not a system that can do a precise monitoring of these wounds so that healthcare systems can manage them with efficiency. The overall aim of our project is to produce a capacitive sensor able to detect a specific molecule in chronic wounds, thus giving information concerning its inflammation state. In this article, we present a system that uses nanoporous Anodic Aluminum Oxide (AAO) grafted with a commercially available anti-MMP9 antibody able to interact with Matrix Metalloproteinase 9, an enzyme that works as an indicator of inflammation. In order to produce a proof-of-concept we chose to compare two methods of functionalization followed by a thorough analysis with biological, electrical and optical testing. This study produced reproducible results for each functionalization method, chemisorption being the best choice for the immobilization of conventional antibodies on AAO-based sensors for a detection of MMP9 in pure and complex conditions. This proof-of-concept and its analysis allowed a better understanding of the needs of the overall project and will be helpful to produce a prototype of smart dressing in the near future.