Regulating CRISPR/Cas9 Using Streptavidin-Biotin Interactions

Comprehensive Summary Currently,CRISPR/Cas9 technology has found widespread applications across various domains.However,the utility of CRISPR/Cas9 is encumbered by issues pertaining to its reliability and safety,primarily stemming from the uncontrolled activity of the system.Therefore,the design and development of CRISPR/Cas9 systems with controllable activity is of paramount importance.Biotin,characterized by its small molecular weight,and streptavidin,distinguished by its substantial spatial steric hindrance,can be harnessed as an ideal OFF switch(termed a"bioactivity brake")due to their interaction characteristics.In this work,we present a strategy that employs the streptavidin-biotin interaction as a"brake system"for CRISPR/Cas9,effectively allowing for the shutdown of the enzymatic activity of CRISPR/Cas9.

Streptavidin-Biotin Complexes as Tools for Modulating an Important DNA Episgenetic Modification

DNA 5-formylcytosine(5fC)is a prominent epigenetic modification within biological systems.Recent investigations have shed light on its pivotal role in governing cell fate,gene expression,and disease pathways.However,our comprehension of the precise control of the 5f site structure to influence its functionality remains limited.In this study,we have successfully achieved precise control over 5fc activity by harnessing the interaction between streptavidin and biotin.This research underscores the potential application of interactions between biomacromolecules and small molecules in advancing the field of DNA epigenetic functional regulation.

Fourier-domain-compressed optical time-stretch quantitative phase imaging flow cytometry

Optical time-stretch(OTS)imaging flow cytometry offers a promising solution for high-throughput and highprecision cell analysis due to its capabilities of high-speed,high-quality,and continuous imaging.Compressed sensing(CS)makes it practically applicable by significantly reducing the data volume while maintaining its highspeed and high-quality imaging properties.To enrich the information of the images acquired with CS-equipped OTS imaging flow cytometry,in this work we propose and experimentally demonstrate Fourier-domaincompressed OTS quantitative phase imaging flow cytometry.It is capable of acquiring intensity and quantitative phase images of cells simultaneously from the compressed data.To evaluate the performance of our method,static microparticles and a corn root cross section are experimentally measured under various compression ratios.Furthermore,to show how our method can be applied in practice,we utilize it in the drug response analysis of breast cancer cells.Experimental results show that our method can acquire high-quality intensity and quantitative phase images of flowing cells at a flowing speed of 1 m/s and a compression ratio of 30%.Combined with machine-learning-based image analysis,it can distinguish drug-treated and drug-untreated cells with an accuracy of over 95%.We believe our method can facilitate cell analysis in both scientific research and clinical settings where both high-throughput and high-content cell analysis is required.