Nano-clays as Potential Pseudo-antibodies for COVID-19

Abstract

Despite several efforts, the development of an effective vaccine for COVID-19 may take a much longer time. Traditional/natural medicine, already experienced by humans, could be an earlier solution. Considering the research team's experience in using nano-clays as high-affinity material for cancer metastasis, melanoma treatment, and bone regeneration, we propose to use these nano-clays for the prevention/treatment of COVID-19. Owing to high affinity, nano-clays would capture the viruses before the latter get engaged with human hACE2. In this study, molecular-level simulations and modeling of the interaction of coronavirus spike and hACE2 proteins were performed with and without nano-clays. The results showed a very high level of affinity/cohesiveness among SARS-CoV-2 spike and nano-clays as compared to the one between the former and hACE2. We premise that these nano-clays since already being used as drug carriers could also be injected as "clays-alone" medicine. Recommendations have also been provided for future in vitro and in vivo studies.

Fig. 1

Schematics of the SARS-CoV-2 attack on human hACE2 and the subsequent immune system response. a, b RBD binding hACE2 without an interference. c RBD complexed with the antibody at receptor attachment site hence competing with hACE2. d RBD complexed with RBD at a site other than where receptor attaches resulting in the alteration of RBD structure and interruption of lock and key binding of RBD to hACE2

Fig. 2

a SEM image and b the corresponding molecular structure of Na-montmorillonite showing the configuration, isomorphous substitution, charge deficiency, and interlayer cations (from [10])

Fig. 3

Molecular-level models of a SARS-CoV-2 spike, b hACE2, and c Na-montmorillonite crystallite formulated in Materials Studio software

Fig. 4

Molecular-level simulation results in Materials Studio Software. a SARS-CoV-2 S and hACE2 (CED = 1 J/cm³), b SARS-CoV-2 S model interacting with twelve crystallites of Na-montmorillonite (CED = 28 J/cm³), and c SARS-CoV-2 S model interacting with twenty-four crystallites of Na-montmorillonite (CED = 154 J/cm³)—obtained using Sorption technique implemented in the software

Fig. 5

Variation of cohesive energy density (CED) for SARS-CoV-2 S-hACE2 and the complexes of the former with different numbers of Na-montmorillonite crystallites

Fig. 6

a Summary of adhesion force measurements among Raji-Raji-FN assembly using AFM, before and after treatment with various proportions of Na-montmorillonite and palygorskite clay nanoparticles [10]. Error bars represent the variations in the trials. b SEM image of the binding of Raji cells and Fibronectin proteins produced by nano-clays

Fig. 7

Three possible mechanisms of interactions of montmorillonite nano-clay with the SARS-CoV-2 spike S: (1) Electrostatic attraction among positively charged nanoparticle edges and Na/Ca ions with negatively charged virus surfaces. (2) Van der Waals attractions. (3) ZP electrostatic interactions

Fig. 8

Interaction mechanism of nano-clay particles with SARS-CoV-2 spike S inhibiting the interaction of the later with hACE2