Paper-based SERS analysis with smartphones as Raman spectral analyzers

SERS (Surface Enhanced Raman Spectroscopy) can realize fingerprint recognition of molecular samples with high detection accuracy and sensitivity. However, rapid and convenient measurement of the Raman spectra of analytes for a point-of-care test (POCT) has put forward a high demand for portable Raman spectrometers, as well as reliable SERS substrates. Hereby, we first utilize a smartphone as a miniaturized Raman spectral analyzer, which has the revolutionary advantages of a friendly human-machine interface, fast measurement time, and good sensitivity. Meanwhile, a paper-based SERS chip was prepared based on commonly used filter paper and silver nanoparticles (AgNP), which was successfully used to detect low concentrations of typical SERS analyte model molecules including rhodamine 6G and crystal violet. The current method of smartphone-based SERS spectroscopy as a POCT device will greatly promote the application of Raman technology in a variety of scenarios, such as safety inspections, pesticide residue detection, water pollution monitoring, and so on. Coupled with paper-based SERS chips with advantages of facile preparation, low cost and good reliability, the current work proves to have a great potential for industrial production and for meeting the vast marketing demand of Raman based POCT technology.</p

Scalable and sustainable synthesis of carbon dots from biomass as efficient friction modifiers for polyethylene glycol synthetic oil

Carbon dots (CDs) have lately inspired extensive interest in tribology, especially in the field of friction modifiers. However, it remains an enormous challenge to obtain satisfactory compatibility between CDs and base oils without laborious and tedious chemical modifications. In this work, for the first time, we reported a scalable and sustainable synthesis of CDs from easily and cheaply available biomass via a one-pot solvothermal route, which used ethanol as the renewable reaction medium and H2O2 as the clean oxidant. Typically, ginkgo leaves acting as the precursors were converted into CDs with an ultrahigh yield of 85.3%. As expected, the ginkgo leaf-derived CDs, abbreviated as GCDs, displayed excellent dispersibility, durable stability, and attractive fluorescence-emission behavior in PEG200. The as-prepared GCDs as additives for PEG200 exhibited remarkable lubricity, favorable load-carrying ability, and long operating life under boundary lubrication. Particularly, the antiwear and friction-reducing performances of PEG200 were promoted by 70.5% and 34.7%, respectively, when only 0.20 wt % of GCDs was blended. Confirmed by the tribological investigations and surface detection of wear tracks, the essential lubrication mechanism of GCDs was chiefly associated with the generation of GCD-inserted tribochemical films with a thickness of about 80 nm and their nanolubrication functions, that is, the synergistic effects of surface organic moieties and carbonaceous cores. This study establishes a technically simple, feasible, versatile, cost-effective, and green methodology to produce CD-based friction modifiers toward PEG synthetic base oils for tribological applications.The authors gratefully acknowledge the National Natural Science Foundation of China (No. 52105173) and the New Faculty Start-up Funding (No. 2081921022) of Chengdu University for providing the financial support for this work

Identification of a distal enhancer regulating hedgehog interacting protein gene in human lung epithelial cellsResearch in context

Summary: Background: An intergenic region at chromosome 4q31 is one of the most significant regions associated with COPD susceptibility and lung function in GWAS. In this region, the implicated causal gene HHIP has a unique epithelial expression pattern in adult human lungs, in contrast to dominant expression in fibroblasts in murine lungs. However, the mechanism underlying the species-dependent cell type-specific regulation of HHIP remains largely unknown. Methods: We employed snATAC-seq analysis to identify open chromatin regions within the COPD GWAS region in various human lung cell types. ChIP-quantitative PCR, reporter assays, chromatin conformation capture assays and Hi-C assays were conducted to characterize the regulatory element in this region. CRISPR/Cas9-editing was performed in BEAS-2B cells to generate single colonies with stable knockout of the regulatory element. RT-PCR and Western blot assays were used to evaluate expression of HHIP and epithelial–mesenchymal transition (EMT)-related marker genes. Findings: We identified a distal enhancer within the COPD 4q31 GWAS locus that regulates HHIP transcription at baseline and after TGFβ treatment in a SMAD3-dependent, but Hedgehog-independent manner in human bronchial epithelial cells. The distal enhancer also maintains chromatin topological domains near 4q31 locus and HHIP gene. Reduced HHIP expression led to increased EMT induced by TGFβ in human bronchial epithelial cells. Interpretation: A distal enhancer regulates HHIP expression both under homeostatic condition and upon TGFβ treatment in human bronchial epithelial cells. The interaction between HHIP and TGFβ signalling possibly contributes to COPD pathogenesis. Funding: Supported by NIH grants R01HL127200, R01HL148667 and R01HL162783 (to X. Z)