Radiothermal Emission of Nanoparticles with a Complex Shape as a Tool for the Quality Control of Pharmaceuticals Containing Biologically Active Nanoparticles

Abstract

It has recently been shown that the titer of the SARS-CoV-2 virus decreases in a cell culture when the cell suspension is irradiated with electromagnetic waves at a frequency of 95 GHz. We assumed that a frequency range in the gigahertz and sub-terahertz ranges was one of the key aspects in the "tuning" of flickering dipoles in the dispersion interaction process of the surfaces of supramolecular structures. To verify this assumption, the intrinsic thermal radio emission in the gigahertz range of the following nanoparticles was studied: virus-like particles (VLP) of SARS-CoV-2 and rotavirus A, monoclonal antibodies to various RBD epitopes of SARS-CoV-2, interferon-α, antibodies to interferon-γ, humic-fulvic acids, and silver proteinate. At 37 °C or when activated by light with λ = 412 nm, these particles all demonstrated an increased (by two orders of magnitude compared to the background) level of electromagnetic radiation in the microwave range. The thermal radio emission flux density specifically depended on the type of nanoparticles, their concentration, and the method of their activation. The thermal radio emission flux density was capable of reaching 20 μW/(m² sr). The thermal radio emission significantly exceeded the background only for nanoparticles with a complex surface shape (nonconvex polyhedra), while the thermal radio emission from spherical nanoparticles (latex spheres, serum albumin, and micelles) did not differ from the background. The spectral range of the emission apparently exceeded the frequencies of the Ka band (above 30 GHz). It was assumed that the complex shape of the nanoparticles contributed to the formation of temporary dipoles which, at a distance of up to 100 nm and due to the formation of an ultrahigh strength field, led to the formation of plasma-like surface regions that acted as emitters in the millimeter range. Such a mechanism makes it possible to explain many phenomena of the biological activity of nanoparticles, including the antibacterial properties of surfaces.

Keywords: drug quality control; nanoparticles; supramolecular structures; thermal radio emission.

Figure 1

Photomicrographs of VLPs mimicking SARS-CoV-2 (a) and rotavirus A (b).

Figure 2

The power density of thermal radio emission of nanoparticle solutions (VLP of rotavirus, INF-α, humic acids, and latex spheres (LS)) and powders containing nanoparticles (AINF-γ and BSA). The data are shown at 23 °C and 37 °C (+t) and irradiation at λ = 412 nm (+hν) (SD, n = 9, p > 0.95).

Figure 3

Time stability of thermal radio emission during heat activation of the AINF-γ preparation (t = 37 °C, Curve 1) and light activation of SARS-CoV-2 VLP (λ = 412 nm, see the inset). Curves 2 and 3–thermal radio emission of lactose powder and placebo to the AINF-γ drug preparation, respectively.

Figure 4

Dependence of the thermal radio emission flux density on the concentration of silver proteinate nanoparticles (the drug concentration is indicated in terms of elemental silver) in a 1 mm layer of paraffin at t = 23 °C (white circles) and t = 37 °C (dark circles–balls).

Figure 5

Kinetics of increase and relaxation of the flux density of the thermal radio emission of humic–fulvic nanoparticles. The arrows indicate the light on and off at 412 nm.

Figure 6

Shielding of the thermal radio emission of the INF-α preparation with screens made of polystyrene (labelled “Polystyr” on the graph; thickness—1 mm), parafilm (“Parafilm”; 1 mm), steel (“Fe”; 5 mm), fabric with copper–nickel particles “RF53” (1 layer), copper grid (“Cu”; 0.2 mm; cell pitch—1 mm).