Rare-earth ions coordination enhanced ratiometric fluorescent sensing platform for quantitative visual analysis of antibiotic residues in real samples

Levofloxacin(LVFX)as a representative drug of quinolone antibiotics is widely used in clinical,and its residues enriched in water bodies and sideline products seriously damage human health.It is imperative to develop a real-time/on-site sensing method for monitoring residual antibiotics.Here,we report a portable sensing platform by utilizing a composite fluorescent nanoprobe constructed by the cerium ions(Ce^(3+))coordination functionalized Cd Te quantum dots(QDs)for the visual and quantitative detection of LVFX residues.This fluorescent probe provides a distinct color variation from red to green,which shows a good linear relationship to LVFX residues concentrations in the range of 0-6.0μmol/L with a sensitive limit of detection(LOD)of 16.3 nmol/L.The smartphone platform with Color Analyzer App installed,which could accomplish quantified detection of LVFX in water,milk,and raw pork with a LOD of 27.9nmol/L.The facile sensing method we proposed realizes rapid visualization of antibiotics residual in the environment and provides a practical application pathway in food safety and human health.

Three-dimensional CeO_(2)@carbon-quantum-dots scaffold modified with Au nanoparticles on flexible substrates for high performance gas sensing at room temperature

High-performance gas sensing materials operated at room temperature(RT) are attractive for a variety of real-time gas monitoring applications,especially with the excellent durability and flexibility of wearable sensor.The constructing heterostructure is one of the significant approaches in design strategies of sensing materials.This heterostructure effectively increases the active site for improving sensing performance and decreasing energy consumption.Herein,the heterostructure of Au nanoparticles modified CeO_(2)@carbon-quantum-dots(Au/CeO_(2)@CQDs) with a three-dimensional(3D) scaffold structure are successfully synthesized by an effective strategy,which can apply for preparing flexible gas sensor.The gas sensing properties of Au/CeO_(2)@CQDs based on flexible substrate are obtained under long-term repeated NO_(2) exposure at RT.Meanwhile,the long-term mechanical stability of this gas sensing device is also detected after different bending cycles.The Au/CeO_(2)@CQDs based on flexible substrate sensor exhibits excellent performance,including higher sensitivity(47.2),faster response(18 s)and recovery time(22 s) as well as longer-term stability than performance of pure materials.The obtained sensor also reveals outstanding mechanical flexibility,which is only a tiny response fluctuation(8.1%) after 500 bending/relaxing cycles.Therefore,our study demonstrates the enormous potential of this sensing materials for hazardous gas monitoring in future portable and wearable sensing platform.

Compressed sensing reconstruction of sparse spectrum based on digital micro-mirror device platform

A new method which employs compressive sensing(CS) to reconstruct the sparse spectrum is designed and experimentally demonstrated. On the basis of CS theory, the simulation results indicate that the probability of reconstruction is high when the step of the sparsity adaptive matching pursuit algorithm is confirmed as 1. Contrastive analysis for four kinds of commonly used measurement matrices: part Hadamard, Bernoulli, Toeplitz and Circular matrix, has been conducted. The results illustrate that the part Hadamard matrix has better performance of reconstruction than the other matrices. The experimental system of the spectral compression reconstruction is mainly based on the digital micro-mirror device(DMD). The experimental results prove that CS can reconstruct sparse spectrum well under the condition of 50% sampling rate. The system error 0.0781 is obtained, which is defined by the average value of the 2-norm. Furthermore, the proposed method shows a dominant ability to discard redundancy.

In-situ monitoring of cell-secreted lactate by electrochemiluminescence sensing under biomimetic microfluidic confinement

Cell migration proceeds in 3D matrices in vivo,which can naturally switch to distinct phenotypes for bet-ter invasion in confined microenvironments.The studies of important metabolites under confinement are extremely meaningful for comprehensive insights into cancer metastasis.The integration of cell confine-ment device and analytical techniques is a key point for in-situ analysis of significant metabolites in vitro.Herein,an electrochemiluminescence(ECL)sensing platform was designed for in-situ monitoring of cell-secreted lactate in highly confined microenvironments.The 3-μm confiner was exactly fabricated via mi-crofabrication and microfluidics technique,and cells in high confinement and low adhesion tended to be round with contractile blebs on cell margins.Significantly,in-situ monitoring of lactate was successfully achieved on the ECL platform with the catalysis of lactate oxidase,in which the levels in different time intervals were acquired in the luminol-hydrogen peroxide system.Furthermore,the results were verified by the liquid chromatography-tandem mass spectrometry(LC-MS/MS)technology,which showed similar fluctuations with the ECL platform.This system offered an available avenue for metabolites analysis in highly confined microenvironments,which may advance deeper insights into metabolic mechanisms of cancer metastasis.