Red/orange dual-emissive carbon dots for pH sensing and cell imaging

The dual-emissive N,S co-doped carbon dots (N,S-CDs) with a long emission wavelength were synthesized via solvothermal method.The N,S-CDs possess relatively high photoluminescence (PL) quantum yield (QY) (35.7%) towards near-infrared fluorescent peak up to 648 nm.With the advanced characterization techniques including X-ray photoelectron spectroscopy (XPS),Fourier transform infrared spectroscopy (FTIR),etc.It is found that the doped N,S elements play an important role in the formation of high QY CDs.The N,S-CDs exist distinct pH-sensitive feature with reversible fluorescence in a good linear relationship with pH values in the range of 1.0-13.0.What is more,N,S-CDs can be used as an ultrasensitive Ag+ probe sensor with the resolution up to 0.4 μM.This finding will expand the application of as prepared N,S-CDs in sensing and environmental fields.

Blood compatible heteratom-doped carbon dots for bio-imaging of human umbilical vein endothelial cells

Carbon dots have unique advantages in biological applications owing to their excellent optical prope rties.However,the biosafety evaluation of carbon dots has limitations owing to cytotoxicity in vitro,and the re is little pre-safety evaluation before in vivo and clinical applications.Whether the carbon dots are or not suitable for applications in vivo,evaluation analysis can be made based on hemolysis and changes in erythrocyte morphology.In this work,a green fluorescent N,S-doped carbon dots(N,S-CDs)were obtained by hydrothermal method,tobias acid,and m-phenylenediamine as precursors.N,S-CDs not only possessed excellent dispersibility,uniform particle size,high quantum yield(37.2%)and stable photoluminescence property but also retain their photostability and stro ng fluorescence intensity in the acid/alkaline solutions,different ionic strengths(NaCl)and under 365 nm UV illumination.Moreove r,the N,S-CDs displayed low cytotoxicity and high cellular uptake efficiency in human umbilical vein endothelial cells(HUVEC)and excellent blood compatibility to the erythrocyte.It is foreseeable that N,S-CDs could be further studied as a promising biological imaging agent in vivo.

Robust and conductive hydrogel based on mussel adhesive chemistry for remote monitoring of body signals

There is a high demand for hydrogels with multifunctional performance(a combination of adhesive,mechanical,and electrical properties)in biological,tissue engineering,robotics,and smart device applications.However,a majority of existing hydrogels are relatively rigid and brittle,with limited stretchability;this hinders their application in the emerging field of flexible devices.In this study,cheap and abundant potato residues were used with polyacrylamide(PAM)to fabricate a multifunctional hydrogel,and chitosan was used for the design of a three-dimentional(3D)network-structured hydrogel.The as-prepared hydrogels exhibited excellent stretchability,with an extension exceeding 900%and a recovery degree of over 99%.Due to the combination of physical and chemical cross-linking properties and the introduction of dopamine,the designed hydrogel exhibits a remarkable self-healing ability(80%mechanical recovery in 2 h),high tensile strength(0.75 MPa),and ultra-stretchability(900%).The resultant products offer superior properties compared to those of previously reported tough and self-healing hydrogels for wound adhesion.Chitosan and potato residues were used as scaffold materials for the hydrogels with excellent mechanical properties.In addition,in vitro experiments show that these hydrogels feature excellent antibacterial properties,effectively hindering the reproduction of bacteria.Moreover,the ternary hydrogel can act as a strain sensor with high sensitivity and a gauge factor of 1.6.The proposed strategy is expected to serve as a reference for the development of green and recyclable conductive polymers to fabricate hydrogels.The proposed hydrogel can also act as a suitable strain sensor for bio-friendly devices such as smart wearable electronic devices and/or for health monitoring.

Whole-milk consumption decreases the risk of inflammatory bowel disease:a two-sample Mendelian rand omization analysis

Objective: The impact of dairy fat on inflammatory bowel disease remained inconclusive. We aimed to compare the effects of whole-milk and skimmed-milk consumption on the risk of inflammatory bowel disease using a Mendelian randomization analysis.Methods: We conducted a genome-wide association study of the preference for whole versus skimmed milk using data for 20,200 whole-milk consumers and 67,847 skimmed-milk consumers from the UK Biobank. The lead single nucleotide polymorphisms in the associated loci were identified at the genome-wide significance level, and were further employed as instrumental variables for whole-milk preference. We conducted a two-sample Mendelian randomization analysis with whole-milk preference as the exposure and inflammatory bowel disease as the outcome. The pleiotropic effects and heterogeneity of the instrumental variables were estimated using Mendelian randomization-Egger regression and CochranQ test, respectively. This study was conducted using the UKB resources under the application "53536" . The UK Biobank was approved by the North West Multi-center Research Ethics Committee, the National Information Governance Board for Health and Social Care in England and Wales, and the Community Health Index Advisory Group in Scotland.Results: The genome-wide association study identified five lead nucleotide polymorphisms associated with whole-milk preference. Mendelian randomization indicated that whole-milk preference significantly decreased the risk of inflammatory bowel disease (β=-1.735,P=0.048). Of the two subtypes, whole-milk preference was associated with a lower risk of Crohn disease (β=-2.549,P=0.032), but had no significant effect on the risk of ulcerative colitis (β=-1.002,P=0.44).Conclusion: Consumption of whole-milk fat may protect against Crohn disease, compared with skimmed milk. This conclusion was based on causal inference in a cohort study, and further validation in randomized controlled trials is warranted.