ABSTRACT
Nanomedicine or nanotechnology exhibits outstanding features to challenge severe health issues including pathogenic viral infections, the most culpable invaders in the present situation. The perpetual mutational pattern in viruses topped with raising resistance to drug epitomizes the current situation as a trigger to explore nanotech platforms in antiviral therapies. Referring to novel physicochemical features of nanomaterials associated with effective drug delivery, it is viewed as an ideal strategy for treatment of viral infections. The coronavirus induced pathogenesis, including MERS, SARS and SARS-CoV-2 infections, has triggered alarming and highly dangerous precedents against existence of humans. Applications of nanotechnology can serve a new direction for disinfection or treatment of viruses. Presently, various types of nanomaterials, such as nanogels, nanospheres, nanocapsules, liposomes, nanoparticles and many others, that have been investigated in vivo and in vitro for successful drug delivery, vaccination, diagnostic assay and device development with anticipation to be translated in advanced clinical practices, need a collective relook. This paper intents to contribute insightful critique of current studies on the efficacy of nanoplatforms as drug transporter, diagnostic tool and vaccine candidate against pathogenic viruses counting the highly pathogenic and incurable "coronaviruses".
ABSTRACT
Using surface-initiated atom-transfer radical polymerization, temperature-responsive block polymers were functionalized on the surface of silica nanocapsules (SNCs) by a "grafting from" technique. Favipiravir, a potential medicine candidate for the treatment of coronavirus disease (COVID-19), was encapsulated in polymer-coated SNCs and further incorporated into welldefined films by layer-by-layer self-assembly. The multilayer films composed of polymer-coated SNCs and poly(methacrylic acid) (PMAA) homopolymers exhibited swelling/deswelling behaviors under the trigger of a temperature stimulus. For the first time, the impact of steric hindrance on the assembling behavior, swelling/ deswelling transition, and delivering capacity of nanocapsule-based multilayer films was investigated. SNCs with coronae of higher steric hindrance resulted in a larger layering distance during film growth. Moreover, the difference in the sustained release rates of the drug indicated their diverse diffusion coefficients and intermolecular interactions within the multilayer films, due to the presence of a methyl spacer at the amino group of nanocapsule coronae and weaker ionic pairing between SNC coronae and PMAA homopolymers. The profile of drug release from the films was dependent on the temperature value of the surrounding environment. At 37 and 40 degrees C, the films were able to efficiently entrap favipiravir, with as low as 50% released in 80 days, whereas a faster favipiravir release was triggered by exposure to a lower temperature value at 25 degrees C. This work demonstrates the first proof-of-concept platform of temperature-responsive SNC-incorporated multilayered films with a well-defined internal structure and a sustained release profile for on-demand in vitro drug delivery.