The Application of Electrochemical Oscillation Methods for Identification of Traditional Chinese Medicine Materials

Electrochemical oscillation reflects the overall characteristics of the system under test in terms of redox activity. It has proven to be advantageous in analyzing and processing complex components of herbal systems, such as polysaccharides and proteins. Therefore, it is widely used in the quantitative or qualitative tests of traditional Chinese medicines (TCMs) for identification and quality control. Electrochemical oscillation has several advantages such as high sensitivity, stability and micro sample requirement. Compared with other traditional methods, the interaction of multi-component in the TCMs was taken into account, which provides new ideas for the search of TCMs. Here, we presented a brief introduction on the progress on the topic, which promoted the development of electrochemical oscillation and the standardization of TCMs in the last twenty years. Electrochemical oscillation method is cheap, sensitive, fast, stable and convenient for the identification and quality control of TCMs. Reaction systems and the visualization of the fingerprints can be improved in the future.

Transferrable Selectivity Profiles Enable Prediction in Synergistic Catalyst Space

Organometallic intermediates participate in many multi-catalytic enantioselective transformations directed by a chiral catalyst, but the requirement of optimizing two catalyst components is a significant barrier to widely adopting this approach for chiral molecule synthesis. Algorithms can potentially accelerate the screening process by developing quantitative structure-function relationships from large experimental datasets. However, the chemical data available in this catalyst space is limited. We report a data-driven strategy that effectively translates selectivity relationships trained on enantioselectivity outcomes derived from one catalyst reaction systems where an abundance of data exists, to synergistic catalyst space. We describe three case studies involving different modes of catalysis (Brønsted acid, chiral anion, and secondary amine) that substantiate the prospect of this approach to predict and elucidate selectivity in reactions where more than one catalyst is involved. Ultimately, the success in applying our approach to diverse areas of asymmetric catalysis implies that this general workflow should find broad use in the study and development of new enantioselective, multi-catalytic processes.

CRISPR/Cas9-mediated base-editing enables a chain reaction through sequential repair of sgRNA scaffold mutations

Cell behavior is controlled by complex gene regulatory networks. Although studies have uncovered diverse roles of individual genes, it has been challenging to record or control sequential genetic events in living cells. In this study, we designed two cellular chain reaction systems that enable sequential sgRNA activation in mammalian cells using a nickase Cas9 tethering of a cytosine nucleotide deaminase (nCas9-CDA). In these systems, thymidine (T)-to-cytosine (C) substitutions in the scaffold region of the sgRNA or the TATA box-containing loxP sequence (TATAloxP) are corrected by the nCas9-CDA, leading to activation of the next sgRNA. These reactions can occur multiple times, resulting in cellular chain reactions. As a proof of concept, we established a chain reaction by repairing sgRNA scaffold mutations in 293 T cells. Importantly, the results obtained in yeast or in vitro did not match those obtained in mammalian cells, suggesting that in vivo chain reactions need to be optimized in appropriate cellular contexts. Our system may lay the foundation for building cellular chain reaction systems that have a broad utility in the future biomedical research.

Definition of CRISPR Cas12a Trans-Cleavage Units to Facilitate CRISPR Diagnostics

The CRISPR diagnostic (CRISPR-Dx) technology that employs the trans-cleavage activities has shown great potential in diagnostic sensitivity, specificity, convenience, and portability, and has been recognized as the next-generation diagnostic methods. However, due to the lack of standardized definition of Cas trans-cleavage enzymatic units, it is difficult to standardize the present CRISPR-Dx systems, which have undoubtedly impeded the development of the CRISPR-Dx industry. To solve the problem, we here first systematically optimized the reaction systems for Cas12a, and then defined its trans-cleavage units (transU), which we believe will be of great importance and interest to researchers in both molecular diagnostic industry and basic research. Moreover, a simple protocol was provided to facilitate a step-by-step measurement of the Cas12a transU, which can also act as a reference for the definition of the transU for other Cas proteins.

Production of 5-hydroxymethylfurfural from Japanese cedar (Cryptomeria japonica) in an ionic liquid, 1-methylimidazolium hydrogen sulfate

Production of 5-hydroxymethylfurfural (5-HMF) from Japanese cedar (Cryptomeria japonica) using an ionic liquid, 1-methylimidazolium hydrogen sulfate ([MIM]HSO4), was investigated. 5-HMF can be produced from C. japonica at temperatures above 120 °C. The maximum yield of 5-HMF was about 9 wt% after 15 min of treatment at 160 °C. However, 5-HMF produced in this process tended to decompose as the treatment continued. To avoid decomposition and to provide a means of recovering 5-HMF from [MIM]HSO4, three reaction systems based on [MIM]HSO4 were investigated: biphasic [MIM]HSO4/organic solvent system, [MIM]HSO4 with vacuum distillation, and [MIM]HSO4 with vacuum steam distillation. The [MIM]HSO4 reaction system combined with vacuum steam distillation was most effective. The maximum yield of 5-HMF was 17.5 wt% after treatment for 45 min at 160 °C. The combination of [MIM]HSO4 treatment with vacuum steam distillation is suitable for 5-HMF production because it is a one-pot process without the need for catalysts or pretreatment.

Colorful and facile in situ nanosilver coating on sisal/cotton interwoven fabrics mediated from European larch heartwood

This study reports on a novel coloration approach for sisal/cotton interwoven fabric via in situ synthesis of European larch (Larix decidua) heartwood-anchored sustainable nanosilver. The heartwood extracts functioned as the reducing and stabilizing agent in reaction systems. The deposited silver nanoparticles (AgNPs) over the fabric surfaces displayed brilliant coloration effects with improved fastness ratings and color strengths (K/S). The successful depositions of nanosilvers were quantified and increasing trends in K/S values with the increase in silver precursor loading were discovered. The concentrations of AgNPs deposited on fabric surfaces were found to be 16 mg/L, 323 mg/L, and 697 mg/L, which were measured through an iCP OES (atomic absorption spectroscopy) test. The K/S values obtained for different loadings of silver precursors (0.5, 1.5, and 2.5 mM (w/v)) are 2.74, 6.76, and 8.96. Morphological studies of the control and AgNP-treated fabrics also displayed a uniform and homogeneous distribution of AgNPs over the fabric surfaces. FTIR (Fourier transform infrared spectroscopy) studies of the sustainably developed materials further confirms the successful bonding between the fabrics and AgNPs. Furthermore, stability against temperature was also noticed as per TGA (thermogravimetric analysis) and DTG (derivative TG) analysis although there was a slight decline from the control sisal/cotton interwoven fabrics observed. Statistically, regression analysis and ANOVA tests were conducted to understand the significance of increased nanosilver loading on sisal/cotton interwoven fabrics. In summary, the perceived results demonstrated successful coloration and functionalization of sisal/cotton interwoven fabrics through green AgNPs, which could indicate a new milestone for industrial production units.