Integrating PCR-free amplification and synergistic sensing for ultrasensitive and rapid CRISPR/Cas12a-based SARS-CoV-2 antigen detection

Antigen detection provides particularly valuable information for medical diagnoses; however, the current detection methods are less sensitive and accurate than nucleic acid analysis. The combination of CRISPR/Cas12a and aptamers provides a new detection paradigm, but sensitive sensing and stable amplification in antigen detection remain challenging. Here, we present a PCR-free multiple trigger dsDNA tandem-based signal amplification strategy and a de novo designed dual aptamer synergistic sensing strategy. Integration of these two strategies endowed the CRISPR/Cas12a and aptamer-based method with ultra-sensitive, fast, and stable antigen detection. In a demonstration of this method, the limit of detection was at the single virus level (0.17 fM, approximately two copies/L) in SARS-CoV-2 antigen nucleocapsid protein analysis of saliva or serum samples. The entire procedure required only 20 minutes. Given our systems simplicity and modular setup, we believe that it could be adapted reasonably easily for general applications in CRISPR/Cas12a-aptamer-based detection.

NF-?B site of promotor mediates nicotine-induced ICAM-1 expression in human umbilical vein endothelial cells / 中国病理生理杂志

AIM: To study the mechanisms of nicotine-induced expression of intercellular adhesion molecule-1(ICAM-1). METHODS: Related luciferase reporter gene plasmids were constructed with molecular cloning techniques;above plasmids and intracontrol plasmid pSV-?-gal were co-transfected into human umbilical vein endothelial cells(HUVECs) with eukaryotic gene transfection techniques; the relative luciferase activities were detected in the transfected HUVECs. RESULTS: Series of luciferase reporter gene containing different sequences of human ICAM-1 promotor and site-directed mutants of NF-?B and Sp-1 in promotor were successfully constructed; Nicotine could increase the expression of luciferase reporter gene plasmid containing-579 bp(pGL3E-579/+36),-230 bp(pGL3E-230/+36) and mutated Sp-1 version(pGL3E-Sp-1-MU)( P

Studies on the repair of oleic acid induced acute lung injury and the changes of elastase and ?-glucuronidase activities during injury / 中国病理生理杂志

Acute lung injury was produced by injection of oleic acid (0.1 ml/kg) intravenously. Within 1 dey after oleic acid, the protein content, total cell counts, elastase, ?_1-antitrypsin and ?-glucuronidase activities were increased in BALF significantly. Histologic examination showed pulmonary hemorrhage, edema and interstitial infiltration of leukocytcs. 3 days after oleic acid, all above changes diminished. 7 days after injection of oleic acid, the changes both in BALF and histologic feature reached normal. The results suggest that, acute lung injury induced by oleic acid could recover completely in 1 week. The role of elastase and ?_1 -Antitrypsin in lung injury and repair was discussed. The possibility of oleic acid induced injury in other organs was noted as well.