Density functional theory study of ?-lactam anti-biotics (penicillin, floxacillin and ampicillin) detection and adsorption onto calix[4]arene

Abstract

In this work, the adsorption and sensing behavior of a calixarene macrocycle toward three ?-lactam anti-biotics was probed by density functional theory (DFT). All calculations were carried out with the B3LYP hybrid functional using the 6-31G(d,p) basis set. The simulations demonstrate that the calix[4]arene scaffold exhibits a pronounced sensing response exclusively for floxacillin: its sensor response factor is roughly six orders of magnitude greater than those obtained for ampicillin and penicillin. Additionally, analysis of frontier orbitals shows a 16.4% contraction of the HOMO–LUMO gap upon floxacillin binding, a perturbation that is visually evident in the density of states profile. Taken together, these findings establish calix[4]arene as a viable electronic sensor for floxacillin under ambient conditions.