Resorc[4]arene Modifiers for Supramolecular Site‐Directed Immobilization of Antibodies on Multi‐Walled Carbon Nanotubes

Abstract

One of the main problems in developing immunosensors featuring carbon nanotubes (CNTs) is immobilizing antibodies (Abs) onto the CNT surface to afford selective binding to target antigens (Ags). In this work, we developed a practical supramolecular Ab conjugation strategy based on resorc[4]arene modifiers. To improve the Ab orientation on the CNTs surface and optimizing the Ab/Ag interaction, we exploited the host-guest approach by synthesizing two newly resorc[4]arene linkers R1 and R2 via well-established procedures. The upper rim was decorated with eight methoxyl groups to promote selective recognition of the fragment crystallizable (F c ) region of the Ab. Moreover, the lower rim was functionalized with 3-bromopropyloxy or 3-azidopropiloxy sub-stituents to bind the macrocycles on the multi-walled carbon nanotubes (MWCNTs) surface. Accordingly, several chemical modifications of MWCNTs were evaluated. After the morphological and electrochemical characterization of nanomaterials, the resorc[4]arene-modified MWCNTs were deposited onto a glassy carbon electrode surface to evaluate their potential applicability for label-free immunosensor development. The most promising system showed an improved electrode active area (A EL ) of almost 20 % and a site-oriented immobilization of the SARS-CoV-2 spike protein S1 antibody (Ab-SPS1). The developed immunosensor revealed a good sensitivity (23.64 μA mL ng À 1 cm À 2 ) towards the SPS1 antigen and a limit of detection (LOD) of 1.01 ng mL À 1 .

Nanoparticles in Electrochemical Immunosensors – A Concept and Perspective

“…Recently, several works have been report using calix [4]arene modified NPs. [193,[196][197][198][199] Among the electrochemical ones, Calcaterra et al, [200] recently designed a resorc [4] arene-modified Au@MNPs for atrazine detection. The cyclic oligomer has been functionalized in the upper rim with carboxylic groups to improve its water solubility.…”

“…Although those structures have been primarily applied to modify solid supports, [148,149,192–195] those attracting features have made the calix[4]arene design suitable for NPs decoration. Recently, several works have been report using calix[4]arene modified NPs [193,196–199] . Among the electrochemical ones, Calcaterra et al., [200] recently designed a resorc[4] arene‐modified Au@MNPs for atrazine detection.…”

Probing the dynamical interaction of the para-sulfonato-calix[4]arene with an antifungal protein

“…Calixarenes, due to their tunable size up to giant calixarenes 16 and to their large possibilities of functionalization [17][18][19][20][21] , are associated with many applications in biological fields, as chemotherapy delivery carriers [22][23][24][25][26][27] , protein inhibitors 28,29 and surface binders-recognizers 15,[30][31][32] .…”