Site‐Directed Antibody Immobilization by Resorc[4]arene‐Based Immunosensors

• Published in: Chemistry : a European journal Vol. 26; no. 38; pp. 8400 - 8406
• Main Authors: Quaglio, Deborah, Mangiardi, Laura, Venditti, Giulia, Del Plato, Cristina, Polli, Francesca, Ghirga, Francesca, Favero, Gabriele, Pierini, Marco, Botta, Bruno, Mazzei, Franco
• Format: Journal Article
• Language: English
• Published: 08-07-2020
• Subjects: immunosensor; macrocycles; resorcarene; site directed immobilization; surface plasmon resonance
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202000989

One of the main problems in the development of immunosensors is to overcome the complexity of binding antibodies to the sensor surface. Most immobilizing methods lead to a random orientation of antibodies with a lower binding site density and immunoaffinity. In order to control the orientation of antibody immobilization, several resorc[4]arene derivatives were designed and synthesized. After the spectroscopic characterization of resorc[4]arene self‐assembled monolayers (SAMs) onto gold films, the surface coverage and the orientation of insulin antibody (Ab‐Ins) were assessed by a surface plasmon resonance (SPR) technique and compared with a random immobilization method. Experimental results combined with theoretical studies confirmed the dipole–dipole interaction as an important factor in antibody orientation and demonstrated the importance of the upper rim functionalization of resorcarenes. Accordingly, resorcarene 5 showed a major binding force towards Ab‐Ins thanks to the H‐bond interactions with the amine protein groups. Based on these findings, the resorcarene‐based immunosensor is a powerful system with improved sensitivity providing new insight into sensor development.
The immobilization of antibodies for optimized immunosensor development has been obtained by using resorc[4]arene as site‐directing tool; this makes it possible to overcome the complexity of binding an antibody to the sensor surface, avoiding the random orientation with a lower binding site density and immunoaffinity. A surface plasmon resonance (SPR) technique has been employed for the characterization of the modified surface as well as to evaluate the heterogeneous kinetics of the model insulin/insulin–Ab interaction.