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Nano Today ; 40: 101243, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1300951


The outbreak of SARS-coronavirus 2 (SARS-CoV2) has become a global health emergency. Although enormous efforts have been made, there is still no effective treatment against the new virus. Herein, a TiO2 supported single-atom nanozyme containing atomically dispersed Ag atoms (Ag-TiO2 SAN) is designed to serve as a highly efficient antiviral nanomaterial. Compared with traditional nano-TiO2 and Ag, Ag-TiO2 SAN exhibits higher adsorption (99.65%) of SARS-CoV2 pseudovirus. This adsorption ability is due to the interaction between SAN and receptor binding domain (RBD) of spike 1 protein of SARS-CoV2. Theoretical calculation and experimental evidences indicate that the Ag atoms of SAN strongly bind to cysteine and asparagine, which are the most abundant amino acids on the surface of spike 1 RBD. After binding to the virus, the SAN/virus complex is typically phagocytosed by macrophages and colocalized with lysosomes. Interestingly, Ag-TiO2 SAN possesses high peroxidase-like activity responsible for reactive oxygen species production under acid conditions. The highly acidic microenvironment of lysosomes could favor oxygen reduction reaction process to eliminate the virus. With hACE2 transgenic mice, Ag-TiO2 SAN showed efficient anti-SARS-CoV2 pseudovirus activity. In conclusion, Ag-TiO2 SAN is a promising nanomaterial to achieve effective antiviral effects for SARS-CoV2.

EBioMedicine ; 61: 103036, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-844322


BACKGROUND: Real-time reverse transcription-PCR (rRT-PCR) has been the most effective and widely implemented diagnostic technology since the beginning of the COVID-19 pandemic. However, fuzzy rRT-PCR readouts with high Ct values are frequently encountered, resulting in uncertainty in diagnosis. METHODS: A Specific Enhancer for PCR-amplified Nucleic Acid (SENA) was developed based on the Cas12a trans-cleavage activity, which is specifically triggered by the rRT-PCR amplicons of the SARS-CoV-2 Orf1ab (O) and N fragments. SENA was first characterized to determine its sensitivity and specificity, using a systematic titration experiment with pure SARS-CoV-2 RNA standards, and was then verified in several hospitals, employing a couple of commercial rRT-PCR kits and testing various clinical specimens under different scenarios. FINDINGS: The ratio (10 min/5 min) of fluorescence change (FC) with mixed SENA reaction (mix-FCratio) was defined for quantitative analysis of target O and N genes, and the Limit of Detection (LoD) of mix-FCratio with 95% confidence interval was 1.2≤1.6≤2.1. Totally, 295 clinical specimens were analyzed, among which 21 uncertain rRT-PCR cases as well as 4 false negative and 2 false positive samples were characterized by SENA and further verified by next-generation sequencing (NGS). The cut-off values for mix-FCratio were determined as 1.145 for positive and 1.068 for negative. INTERPRETATION: SENA increases both the sensitivity and the specificity of rRT-PCR, solving the uncertainty problem in COVID-19 diagnosis and thus providing a simple and low-cost companion diagnosis for combating the pandemic. FUNDING: Detailed funding information is available at the end of the manuscript.

Bacterial Proteins/metabolism , Betacoronavirus/genetics , CRISPR-Associated Proteins/metabolism , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , Endodeoxyribonucleases/metabolism , RNA, Viral/metabolism , Real-Time Polymerase Chain Reaction/methods , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/diagnosis , Coronavirus Infections/pathology , Coronavirus Infections/virology , Coronavirus Nucleocapsid Proteins , Humans , Limit of Detection , Nasal Cavity/virology , Nucleic Acid Amplification Techniques/methods , Nucleic Acid Amplification Techniques/standards , Nucleocapsid Proteins/genetics , Nucleocapsid Proteins/metabolism , Pandemics , Phosphoproteins , Pneumonia, Viral/diagnosis , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Polyproteins , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/standards , Reference Standards , SARS-CoV-2 , Viral Proteins/genetics , Viral Proteins/metabolism
Non-conventional in 0 | WHO COVID | ID: covidwho-680473


The coronavirus disease 2019 (COVID-19) pandemic is a serious biosafety event that is causing a severe impact on the global society and economy. Thus, the importance of biosafety is once again being valued worldwide. Due to the outbreak of COVID-19, most national governments have been encouraged to speed up the development of biosafety, which places higher requirements on researchers in biosafety and relevant fields. Many problems have been exposed due to the outbreak of COVID-19, including unavailability of effective drugs and vaccines, difficulty in fast or real-time virus detection, insufficient protective equipment, and shortage of transportation equipment for infected patients. To a certain extent, these biosafety problems are partly due to the limited biosafety-related research in materials science. Currently, the tremendous research efforts in materials science around the world have provided a wide variety of materials with peculiar properties to solve biosafety problems. This review attempts to give a perspective on how the development of novel materials can help scientists tackle the challenges in biosafety. Considering the importance of materials science in the biosafety field, it is urgent for us to officially propose the brand new concept of "biosafety materials", which can be a future scientific discipline that utilizes materials science and theory simultaneously to produce materials, related products, and equipment to solve biosafety problems. Herein, we have aimed to draw worldwide attention on the new discipline of biosafety materials and the active cooperation between materials scientists and biosafety-related scientists to propel its development.