CRISPR-Cas13a mediated nanosystem for attomolar detection of canine parvovirus type 2

Canine parvovirus type 2(CPV-2) infection is the most lethal disease of dogs with higher mortality in puppies worldwide.In today’s world,dogs are an integral part of our communities as well as dogs breeding and rearing has become a lucrative business.Therefore,a fast,accurate,portable,and costeffective CPV-2 detection method with the ability for on-site detection is highly desired.In this study,we for the first time proposed a nanosystem for CPV-2 DNA detection with RNA-guided RNA endonuclease Cas13 a,which upon activation results in collateral RNA degradation.We expressed LwCasl3 a in prokaryotic expression system and purified it through nickel column.Activity of Cas13 a was verified by RNA-bound fluorescent group while using a quenched fluorescent probe as signals.Further Cas13 a was combined with Recombinase polymerase amplification(RPA) and T7 transcription to establish molecular detection system termed specific high-sensitivity enzymatic reporter un-locking(SHERLOCK) for sensitive detection of CPV-2 DNA.This nanosystem can detect 100 amol/L CPV-2 DNA within 30 min.The proposed nanosystem exhibited high specificity when tested for CPV-2 and other dog viruses.This CRISPR-Cas13 a mediated sensitive detection approach can be of formidable advantage during CPV-2 outbreaks because it is time-efficient,less laborious and does not involve the use of sophisticated instruments.

Extracellular vesicles based electrochemical biosensors for detection of cancer cells:A review

Extracellular vesicles(EVs)derived from cancer cells are considered as ideal biomarker for liquid biopsy in cancer diagnosis,and are stable and abundant.Electrochemical methods for the detection of EVs are prefe rred over co nventional methods such as Western blotting and enzyme-linked immunosorbent assay for their high sensitivity and real-time detection.This article summaries studies proposing the electrochemical methods utilizing immunological and molecular methodologies for detecting EVs derived biomacromolecules such as miRNAs and transme mbrane protein for cancer diagnosis.Moreover,the electrochemical detection methods are compared and future prospects for the development of electrochemical methods for EVs detection are concluded.

Spermine increases bactericidal activity of silver-nanoparticles against clinical methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus(MRSA) has emerged worldwide as a major multidrugresistant pathogen that causes notable morbidity and mortality. Fast emerging of MRSA prevalence requires special attention for strengthening the inventory of antimicrobial compounds. Silver nanoparticles(AgNPs) have been widely used to treat multi-drug resistant pathogens due to the unique antibacterial properties, meanwhile spermine has been proven to exert outstanding inhibition effect to S.aureus with not yet fully understood mechanisms. The aim of this study was to investigate the synergistic effect of AgNPs and spermine as well as to determine the antibacterial activity of their combination against MRSA strains. Several clinical MRSA isolates and ATCC BAA-1026 were used to determine minimum inhibitory concentration(MIC) and fractional inhibitory concentration indices(FICI) of AgNPs and spermine, and a synergistic effect was observed. This phenomenon was further confirmed by growth curve and time-killing assays, showed that spermine could be used as an adjuvant for AgNPs in the treatment of MRSA infections.