Resorc[4]arene-based site directed immobilization of antibodies for immunosensors development

One of the main problems in the development of immunosensors is to overcome the complexity of binding antibody to the surface of the sensor. In fact, antibodies need to be immobilized with a high density and good orientation to allow the easy detection of antigens. The influence of nonspecific bindings should be minimized to improve the detection performance. Most of immobilizing methods lead to randomly oriented antibodies on the surface, which results in a low density of binding sites and alleviation of immunoaffinity of the antibodies. Therefore, oriented immobilization is required for the improvement of the performance enhancement. Calix[4]arene derivatives have been proposed as an alternative tool for the oriented immobilization of antibodies thanks to their particular structure of lower and upper rims.1 To ensure the orientation control of antibodies on the sensor surface, we synthesized several resorc[4]arene derivatives able to self-assemble onto gold surface thanks to the thiol groups present on their structure.2 Resorcarene, a type of calixarene, is a macrocycle oligomer based on the condensation of resorcinol and aldehyde. The immobilization characteristics of these artificial linkers have been evaluated by means of Surface Plasmon Resonance (SPR) technique comparing the results obtained with a random immobilization method based on EDC/NHS and an oriented immobilization with boronic acid derivatives of insulin antibody for the development insulin immunosensors. The results obtained put in evidence that the synthesized compounds show an enhancement of the insulin-insulin antibody interaction, resulting in a significative increase of the immunosensor sensitivity.