Aspects of Nanotechnology for COVID-19 Vaccine Development and Its Delivery Applications.

Coronavirus, a causative agent of the common cold to a much more complicated disease such as "severe acute respiratory syndrome (SARS-CoV-2), Middle East Respiratory Syndrome (MERS-CoV-2), and Coronavirus Disease 2019 (COVID-19)", is a member of the coronaviridae family and contains a positive-sense single-stranded RNA of 26-32 kilobase pairs. COVID-19 has shown very high mortality and morbidity and imparted a significantly impacted socioeconomic status. There are many variants of SARS-CoV-2 that have originated from the mutation of the genetic material of the original coronavirus. This has raised the demand for efficient treatment/therapy to manage newly emerged SARS-CoV-2 infections successfully. However, different types of vaccines have been developed and administered to patients but need more attention because COVID-19 is not under complete control. In this article, currently developed nanotechnology-based vaccines are explored, such as inactivated virus vaccines, mRNA-based vaccines, DNA-based vaccines, S-protein-based vaccines, virus-vectored vaccines, etc. One of the important aspects of vaccines is their administration inside the host body wherein nanotechnology can play a very crucial role. Currently, more than 26 nanotechnology-based COVID-19 vaccine candidates are in various phases of clinical trials. Nanotechnology is one of the growing fields in drug discovery and drug delivery that can also be used for the tackling of coronavirus. Nanotechnology can be used in various ways to design and develop tools and strategies for detection, diagnosis, and therapeutic and vaccine development to protect against COVID-19. The design of instruments for speedy, precise, and sensitive diagnosis, the fabrication of potent sanitizers, the delivery of extracellular antigenic components or mRNA-based vaccines into human tissues, and the administration of antiretroviral medicines into the organism are nanotechnology-based strategies for COVID-19 management. Herein, we discuss the application of nanotechnology in COVID-19 vaccine development and the challenges and opportunities in this approach.

Sunlight powered degradation of pentoxifylline Cs0.5Li0.5FeO2 as a green reusable photocatalyst: Mechanism, kinetics and toxicity studies.

The degradation of Pentoxifylline (PXF) was achieved successfully by green energy in a built-in solar photocatalytic system using hybrid LiCs ferrites (Li0.5Cs0.5FeO2) as magnetically recoverable photocatalysts. Kinetics showed a first-order reaction rate with maximum PXF removal of 94.91% at mildly acidic pH; additionally, the ferromagnetic properties of catalyst allowed recovery and reuse multiple times, reducing costs and time in degradation processes. The degradation products were identified by HPLC-MS and allowed us to propose a thermodynamically feasible mechanism that was validated through DFT calculations. Additionally, toxicity studies have been performed in bacteria and yeast where high loadings of Cs showed to be harmful to Staphylococcus aureus (MIC≥ 4.0 mg/mL); Salmonella typhi (MIC≥ 8.0 mg/mL) and Candida albicans (MIC≥ 10.0 mg/mL). The presented setup shows effectiveness and robustness in a degradation process using alternative energy sources for the elimination of non-biodegradable pollutants.

Role of particle size in assessment of physico-chemical properties and trace elements of Indian fly ash.

In this paper, the effect of particle size on the physico-chemical, mineralogical, and leaching behavior of Indian fly ash was studied. Experiments were carried out to study the leaching of different elements such as Mg, Cr, Zn, Pb, Mn, Fe, Cu, Co, Mo, and Ni from Indian fly ash. During the experiments, the liquid-to-solid (L/S) ratio of the fly ash was taken as 9/1, 8/2, 7/3, 3/2, 1/1, and 2/3. The effect of four different particle size ranges (below 53, 53-75, 75-106, and 106-150 µm) of fly ash was analyzed. The ASTMD-3987 method was used to analyze the presence of trace elements from fly ash. In the ASTM D-3987 method, distilled water was used for extraction of leachate. Fly ash slurry samples were agitated in a lubricating type temperature-controlled Remi orbital shaker for a time duration of 18 hours with speed of 100 revolutions per minute (rpm) at a temperature of 25ºC. Distilled water does not save cost as well as being easily available. The leaching test of trace elements from fly ash was investigated at different pH conditions in order to predict the environmental effect from the ash disposal on the groundwater quality. Results revealed that pH of slurry suspension increases with increase in particle size. The pH value of fly ash slurries was negligibly affected by the decrease in L/S ratio for all particle sizes. Fine particles of fly ash produce a more harmful effect as compared to the coarser range of fly ash particles.

Stabilization of Ag-Au Bimetallic Nanocrystals in Aquatic Environments Mediated by Dissolved Organic Matter: A Mechanistic Perspective.

Gold and silver nanoparticles can be stabilized endogenously within aquatic environments from dissolved ionic species as a result of mineralization induced by dissolved organic matter. However, the ability of fulvic and humic acids to stabilize bimetallic nanoparticles is entirely unexplored. Elucidating the formation of such particles is imperative given their potential ecological toxicity. Herein, we demonstrate the nucleation, growth, and stabilization of bimetallic Ag-Au nanocrystals from the interactions of Ag+ and Au3+ with Suwannee River fulvic and humic acids. The mechanisms underpinning the stabilization of Ag-Au alloy NPs at different pH (6.0-9.0) values are studied by UV-vis spectrophotometry, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). Complexation of free Ag+ and Au3+ ions with the Lewis basic groups (carbonyls, carboxyls, and thiols) of FA and HA, followed by electron-transfer from redox-active moieties present in dissolved organic matter initiates the nucleation of the NPs. Alloy formation and interdiffusion of Au and Ag atoms are further facilitated by a galvanic replacement reaction between AuCl4- and Ag. Charge-transfer from Au to Ag stabilizes the formed bimetallic NPs. A more pronounced agglomeration of the Ag-Au NPs is observed when HA is used compared to FA as the reducing agent. The bimetallic NPs are stable for greater than four months, which suggests the possible persistence and dispersion of these materials in aquatic environments. The mechanistic ideas have broad generalizability to reductive mineralization processes mediated by dissolved organic matter.

The incidence of oesophageal adenocarcinoma in non-dysplastic Barrett's oesophagus: a meta-analysis.

INTRODUCTION: The risk of oesophageal adenocarcinoma (OAC) in non-dysplastic Barrett's oesophagus (BO) may have been overestimated. The objective was to estimate the incidence of OAC in patients with BO without dysplasia. METHODS: The authors searched MEDLINE and EMBASE from 1966 to 2011 and performed a bibliographic review of previous publications, excluding abstracts, non-peer-reviewed publications and those not published in English, for prospective or retrospective studies of the incidence of OAC in patients with BO. They excluded patients with any degree of dysplasia at baseline and those without documented intestinal metaplasia. Studies were independently reviewed by two individuals. 57 of 3450 studies were included. The authors extracted information on number of patients with BO, length of follow-up, incident cases of OAC, mean age of patients, country of origin, whether prospective or retrospective, mean length of BO segments and mortality from causes other than OAC. Study quality was assessed by the Ottawa Newcastle criteria. RESULTS: The 57 included studies comprised 11,434 patients and 58,547 patient-years of follow-up. The pooled annual incidence of OAC was 0.33% (95% CI 0.28% to 0.38%). Among 16 studies that provided appropriate information on mortality, there were 56 incident cases of OAC but 684 deaths from apparently unrelated causes. Among 16 studies that provided information on patients with short-segment BO, the annual incidence of OAC was only 0.19%. CONCLUSIONS: The incidence of OAC in non-dysplastic BO is around 1 per 300 patients per year. The incidence of OAC in short-segment BO is under 1 per 500 patients per year.