Single-stranded circular DNA theranostics.

The past decade has witnessed the blossom of nucleic acid therapeutics and diagnostics (theranostics). Unlike conventional small molecule medicines or protein biologics, nucleic acid theranostics have characteristic features such as the intrinsic ability as "information drugs" to code and execute genetic and theranostic information, ready programmability for nucleic acid engineering, intrinsic stimulatory or regulatory immunomodulation, versatile functionalities, and easy conformational recovery upon thermal or chemical denaturation. Single-stranded circular DNA (circDNA) are a class of single-stranded DNAs (ssDNA) featured with their covalently-closed topology. In addition to the basic advantages of nucleic acids-based materials, such as low cost, biocompatibility, and simplicity of chemical modification, the lack of terminals in circDNA prevents exonuclease degradation, resulting in enhanced biostability relative to the corresponding linear ssDNA. circDNA has been explored for versatile theranostic applications. For instance, circDNA has been extensively studied as templates for bioanalytical signal amplification and the synthesis of nano-/micro-/macro- biomaterials via rolling circle amplification (RCA) and rolling circle transcription (RCT) technologies. circDNA has also been commonly used as the scaffolds for the self-assembly of versatile DNA origami. Finally, circDNA has been implemented as theranostic aptamers, miRNA inhibitors, as well as clustered regularly interspaced short palindromic repeats-CRISPR-associated proteins (CRISPR-Cas) gene editing donors. In this review article, we will discuss the chemistry, characteristic properties, and the theranostic applications of circDNA (excluding double-stranded circular DNA such as plasmids); we will also envision the challenges and opportunities in this research field.

Optimization of the Working Procedure of Radionuclide Treatment Ward during 2019-nCoV Prevention

Since the end of 2019, Novel Coronavirus Pneumonia (2019-nCov) has appeared and spread rapidly in the world. During the epidemic period, how to control the infection in the working procedure of radionuclide treatment ward is a clinical protection problem that must be solved. If a novel coronavirus pneumonia (NCP) is suspected or diagnosed, the most important thing is to isolate the relevant doctors and patients on the spot in time and initiate relevant NCP clinical emergency plans and procedures. When the radioactive infected medical waste is disinfected, it should be treated as radioactive waste. Therefore, it is necessary to optimize the working procedures of radionuclide therapy ward.