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We developed an electrochemical impedance spectroscopy (EIS) biosensor based on bacteriophage long tail fibre proteins (LTFPs) to capture and detect Salmonella. First, based on the genetic information of a Salmonella enterica bacteriophage (SEP37), we found that the genes ORF99, ORF100, and ORF256 encode proteins associated with host recognition. We used the pETdue1 plasmid to construct ORF99–ORF100 and ORF256 co-expression vectors to express (LTFPs) in Escherichia coli and used purified LTFPs as specific biorecognition elements. Then, we fixed gold nanoparticles (AuNPs), cysteamine (Cys), and LTFPs on a gold disk electrode surface via layer-by-layer assembly to construct an EIS biosensor. Salmonella in the sample can be captured by LTFPs on the electrode surface and reduce the electron transfer sites. We applied the EIS biosensor to detect Salmonella spiked in lake water. It showed a good linear relationship within the concentration range of 10 ∼ 1 × 106 colony-forming units (CFU)/mL. The detection limit was 9 CFU/mL. This method based on bacteriophage LTFPs does not require complex pretreatment steps and extends the application of tail fibre proteins as a biorecognition element in the detection field. [Display omitted] • ORF99-100 and ORF256 were inserted into plasmid to construct co-expression vector. • The long tail fibre protein of phage SEP37 was co-expressed in E. coli. • This protein was used as bio-recognition element to construct an EIS biosensor. • This biosensor can quickly detect Salmonella in lake water samples. • This method allowed a detection limit of 9 CFU/mL for Salmonella. [ABSTRACT FROM AUTHOR]

Atractylodis Macrocephalae Rhizoma (AMR) is a bulk herbal foods, which can invigorate spleen and supplement Qi to help health. The accurate identification of the authenticity and origin of AMR is a prerequisite for the safe use and quality control. Herein, a dual-channel colorimetric sensor based on metal ions mediated color transformation of gold nanoparticles (AuNPs) was constructed to identify the authenticity and origin of AMR. The Ag+ / cetyltrimethylammonium chloride modified AuNPs (CTAC-AuNPs) sensing channel and Cr3+ / trisodium citrate modified AuNPs (TCA-AuNPs) sensing channel were rationally designed based on two mechanisms that are the silver deposition and the induced aggregation, respectively. When AMR extracts from different origins or its counterfeits were added to the colorimetric sensor, significantly different terpenoids in extracts can bind to Ag+ or Cr3+ to produce different color transformations. AMR samples from three origins (Zhejiang, Hunan and Anhui) and the counterfeit samples (Gynura japonica (Thunb.) Juel., and Atractylodis Rhizoma) were all accurately classified using the dual-channel colorimetric sensor combined with PLSDA. Our sensor has obvious advantages of simple and instrument-free analysis procedure, which will provide a new idea for the convenient identification of AMR and other herbal foods. [Display omitted] • AuNPs-based dual-channel colorimetric sensor for identifying AMR and its origin. • Two color change systems of AuNPs mediated by Ag+ and Cr3+ were developed in sensor. • The complexation between extracts and metal ions resulted in different color changes. • AMR authenticity and origin can be accurately identified by naked eye or PLSDA. • This method is convenient, accurate and instrument-free, suitable for on-site assay. [ABSTRACT FROM AUTHOR]

Graphical abstract A novel reliable strategy for the fabrication of nanoporous Ag films by dealloying Ag/α-Fe 2 O 3 nanocomposites as low-cost precursor alloy. Highlights • Nanoporous silver film was fabricated by dealloying a low-cost Ag/α-Fe 2 O 3 nanocomposite in dilute acid solution. • Nanoporous Ag film with different ligament size was synthesized by etching in different dilute acid solutions. • A uniform nanoporous Ag film with smaller ligament size was synthesized in dilute sulfuric acid and exhibited strong SERS performance. • The synthesized nanoporous silver film exhibited good SERS sensitivity, uniformity and reproducibility for detection of Sudan III. Abstract A facile and reliable method for fabrication of nanoporous Ag film as surface-enhanced Raman spectroscopy (SERS) substrates was developed by dealloying the low-cost Ag/α-Fe 2 O 3 nanocomposite in dilute acid solution. Influencing parameters such as different dealloying solutions, electrolyte concentration and dealloying time were optimized, and a uniform nanoporous Ag film of tunable and smaller ligament size was synthesized by etching the nanocomposite in sulfuric acid as a dealloying solution, while hydrochloric acid produced coarsened Ag nanoporous structures. Besides, the ligament size of the synthesized nanoporous Ag film increased with the electrolyte concentration and dealloying time. SERS activity of the as-synthesized nanoporous Ag film was evaluated using R6G as Raman probe, and the nanoporous Ag film with smaller ligament size exhibited strong SERS activity with a SERS enhancement factor of 7.47 × 106. The substrate exhibited good sensitivity and uniformity (RSD, 13.3%), and practical applicability for SERS detection of Sudan III, a synthetic organic dye banned as food additives, and achieved a detection limit of 0.5 μM. More importantly, the developed method ensures low-cost and reliable method of nanoporous materials fabrication from low-cost semiconductor based nanomaterials for applications in wide variety of fields. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two heteroleptic Ir(III) complex with AIPE properties were synthesized. • Information inks were prepared from Ir(III) complexes for data encryption. • Temperature was served as the "key" or "lock" of confidential information. Abstract In the present work, two environmentally friendly inks were obtained, capable of achieving information encryption based on two Ir(III) complexes with both multi-stimuli-sensitive and aggregation-induced phosphorescent emission (AIPE) properties. Two inks were prepared from the Ir(III) complexes, respectively. Interestingly, the two inks were coated on glass films and heated; a change in color was then observed under ultraviolet (UV) excitation. The color-changing temperatures of the films were 220 and 180 °C, meaning that temperature could be utilized as the "key" or "lock" to confidential information. More specifically, the encrypted information could be decrypted only by heating the glass film to the correct temperature; excessive heating caused the permanent damage and hiding of the information. All results indicated that the inks were promising solutions for information encryption. [ABSTRACT FROM AUTHOR]

The existence of a sensitive, accurate and convenient method to visualize latent fingermarks (LFs) is of great importance for police identification. In this work, a novel heteroleptic cationic Ir(III) complex ( DX-5 ), which exhibits dual emission ( λ max  = 362 nm, Ф  = 0.16 and λ max  = 494 nm, Ф  = 0.59) and aggregation-induced phosphorescent emission (AIPE) characteristics, was designed and synthesized. This complex was used to enhance the visualization of LFs on different surfaces of porous and non-porous substrates. The results illustrate that complex DX-5 can define the details of LFs up to the third level within 5 min, proving to be a candidate material for criminal investigations applications. [ABSTRACT FROM AUTHOR]

A novel ion-exchange polymer-metal composite (IPMC) actuator is fabricated by sandwiching sulfonated fluorene blocked polysulfone (SDPF- b -PSU) between two Pt nanograin sheets. With increased concentration of chlorosulfonic acid, the SDPF- b -PSU film with more sulfonic groups exhibits strong ion exchange capacity, high Li + ion conductivity, and ordered phase separation, which may contain an increased number of cations and possess larger and better interconnected inner channels for ion migration, thus providing the power to produce large force and power outputs. The SDPF- b -PSU film also exhibits enhanced mechanical performance and water uptake when compared to the pure Nafion film, providing a strong, hydrated matrix to support IPMC functions. At the driving voltage of 4 V, the SDPF- b -PSU actuator exhibits a strong force output which is 11 folds higher than that of the pure Nafion actuator. [ABSTRACT FROM AUTHOR]

In this work, highly photoluminescent glycine (GLY) functionalized graphene quantum dots (GQDs) (GLY-GQDs) were synthesized by a simple and green pyrolysis method employing ethylene glycol as carbon source, GLY as functional molecule. The as-synthesized GLY-GQDs exhibited excellent water solubility with a fluorescence quantum yield of 21.7%. The fluorescence of GLY-GQDs was intensively quenched by Ce 4+ via forming non luminescent complexes of GLY-GQDs-Ce 4+ . When ascorbic acid (AA) was in presence, Ce 4+ was reduced to Ce 3+ and the fluorescence of GLY-GQDs regained. In the light of this theory, a simple AA sensor was fabricated without complicated, costly and time-consuming operations. Under the optimal conditions, the fluorescence recovery ratio and the concentration of AA has a linear relationship in the range of 0.03–17.0 μM and with a detection limit of 25 nM which was one order higher sensitive than the reported methods Furthermore, this established sensor system also shows a high selectivity toward AA over a wide range of common biological molecules such as uric acid, dopamine and glutathione and so on. The proposed method was successfully applied for the AA detection in serum samples. All these suggested the potential of this GLY-GQDs based sensor in the clinical analysis. [ABSTRACT FROM AUTHOR]

Flow chemiluminescence (CL) is widely applied for detection of heavy metal ions in environment, but it is seldom used in economical, practical, or affordable settings because non- and minimally instrumented flow driving is difficult to achieve. Here, we first report a gravity and capillary force-driven flow CL (GCF-CL) lab-on-cloth device, toward development of low-cost, easy-to-use, portable, minimally-instrumented platform for determination of trivalent chromium [Cr(III)] in water, where a difference in height between two zones on cloth creates a fast flow of CL trigger solution. Wax screen-printing was used to fabricate ultra-low-cost cloth-based devices, and the light emitted from the Cr(III)-catalysed oxidation of luminol by H 2 O 2 was imaged using an inexpensive portable CCD camera. Under optical conditions, Cr(III) could be determined over the range of 0.01–100 mg/L, with a detection limit of 6.2 μg/L, an analysis time of less than 30 s per sample, and RSDs of 6.2%, 3.1% and 1.7% for 0.05, 0.5 and 5 mg/L Cr(III) (n = 5). The proposed GCF-CL lab-on-cloth was successfully applied for measuring Cr(III) in water samples, with recoveries of 100.67-111.70% and RSDs of 4.73–6.88%. Thus, the presented method should have the potential for portable field applications in environmental and public health fields. [ABSTRACT FROM AUTHOR]

The arsenic contamination of aquatic food has emerged as a serious concern in recent years due to its hazardous effect on human health. Herein, the multifunctional Fe 3 O 4 @NaGdF 4: Yb: Er (Fe@UCNPs) with fluorescent and magnetic dual properties were fabricated and subsequently applied to construct a platform for detecting the arsenic (As(III)). A luminescence resonance energy transfer (LRET) biosensor was developed with the aptamer-modified magnetized upconversion nanoparticles (Fe@UCNPs) as the donor and tetramethylrhodamine (TAMRA) as the acceptor. Most importantly, Fe@UCNPs revealed highly integrated magnetic and fluorescence properties, thus, allowing the enrichment of targets in the fresh solution by magnetic separation, and avoiding the interference from the detection environment, along with enabling the signal accumulation and amplification. Moreover, the sensor was successfully used for the sensing analysis of As(III) in real samples (fish and shrimp), demonstrating that the biosensor to be a sensitive and specific quantitative platform for arsenic monitoring. [Display omitted] • A novel aptasensor based on the LRET between multifunctional UCNPs and TAMRA has been developed. • The proposed sensor was successfully used for the sensing analysis of As3+ in real samples. • The biosensor achieved accurate separation and detection without the environmental disturbances. [ABSTRACT FROM AUTHOR]

Changes in the composition of type I and type III collagen in tissue can shed light on various diseases. However, many of the current collagen detection techniques require invasive and destructive tissue sampling. In this study, a low cost, low complexity light emitting diode (LED) based system was developed to realize both non-invasive detection and specific discrimination of collagen and elastin variations in tissue based on fluorescence lifetimes. Modulated LED excitation was applied to frequency domain (FD) fluorescence lifetime spectroscopy to calculate tissue autofluorescence lifetimes. Using this method, fluorescence lifetimes from collagen type I versus type III were clearly separated at 3.95 ns and 5.01 ns, respectively, distinct from the elastin lifetime at 6.78 ns. The probe was tested on bovine ocular tissues, with cornea showing much shorter average lifetime of 4.27 ns than sclera at 7.48 ns. Furthermore, measurements of an 8 mm murine skin wound at 14 days post-wounding also showed distinct, longer average lifetimes at 9.74 ns versus normal skin at 6.72 ns. This FD tissue detection technique can potentially offer a way to examine tissue structures and discern the underlying pathology nondestructively. [ABSTRACT FROM AUTHOR]

A novel paper-based open bipolar electrode-electrochemiluminescence (P- o -BPE-ECL) sensing has been developed for visual detection. Wax-screen-printing was employed to make microfluidic channels on filter paper, and the carbon ink-based BPE and driving electrodes were screen-printed on paper. An inexpensive CCD camera was used as a detector for imaging sensing. In this study, two P- o -BPE-ECL imaging sensing platforms were demonstrated. For the first one, a hydrophilic paper channel was used to host a single “band”-shaped BPE. Under optimal conditions, this P- o -BPE-ECL platform successfully fulfilled the imaging sensing of tri- n -propylamine (TPA) with a linear range from 10 to 1000 μM with a detection limit of 8.7 μM. In addition, the determination of H 2 O 2 using this platform could be performed in the linear range of 50 μM to 5000 μM with a detection limit of 46.6 μM. For the second platform, an open BPE array configuration has been proposed for P- o -BPE-ECL sensing, where eleven BPEs were stridden across the two legs of the “U”-shaped paper channel. On this prototype, a simple screening application has been performed. These results show that the proposed strategy offers great promise in providing a simple, low-cost, rapid and environment-friendly solution for biochemical applications. [ABSTRACT FROM AUTHOR]

Sesame oil is a kind of vegetable oil, which is loved by people all over the world due to its unique aroma, edible and medicinal value. Driven by interests, counterfeit and shoddy sesame oil products often appear on the market. This study is based on the color change caused by the competitive coordination of Zn2 + at the phase interface between four polyphenol dyes (Alizarin Red S, bromocatechol red, pyrogallol red and catechol violet) and volatile authenticity markers (VAM) in sesame oil. The DD-SIMCA model was constructed based on the RGB values of each sensing point after the reaction of real sesame oil and adulterated sesame oil with four polyphenol dyes. The results of the DD-SIMCA classification model show that the accuracy of sesame oil classification can reach 100%, and the result of the array sensor is much better than that of the single dye. Furthermore, the PLSR quantitative analysis model is used to verify that the RGB value obtained by the sensor is linearly related to the adulteration concentration. Therefore, this study established a visual array sensor for rapid authenticate of sesame oil adulteration based on the flavor compounds. [Display omitted] • Targeted identification of sesame oil adulteration based on its volatile compounds. • A four channel array sensor was developed to detect the authenticity of sesame oil. • This sensor is based on the competitive coordination of dyes and sesame oil to Zn2+. • Based on DD-SIMCA, the authenticity of sesame oil can be authenticated. • This work provides a new method for visual instrument free detection of sesame oil. [ABSTRACT FROM AUTHOR]

Pathogenic bacteria, as a major cause of foodborne diseases, pose a serious threat to human health, which urges the development of sensitive and accurate detection methods. Herein, a fluorescent genosensor was designed for Staphylococcus aureus (S. aureus) detection based on fluorescent probes and graphene oxide quantum dots (GOQDs). The π-π stacking and hydrogen bond interactions between GOQDs and specific single-stranded DNA (ssDNA) of the fluorescent probes were exploited by the developed genosensor. The interactions brought the GOQDs to the surface of the fluorescent probes, quenching strong upconversion fluorescence. However, the hybridization of the recognition probes anchored on the fluorescent reporters with complementary nuc target obstructed the interactions, causing the fluorescence to gradually increase with the increasing concentration of complementary nuc target. Consequently, the target-specific sensor exhibited high sensitivity with a LOD of 0.98 × 10−17 mol L−1 and a linear range from 1 × 10−17 to 1 × 10−11 mol L−1. Moreover, the genosensor was successfully applied for real sample analysis with excellent recoveries. Significantly, the sensor could be used for the detection of other pathogens in actual samples by replacing recognition probes and primers. [Display omitted] • A fluorescent genosensor was developed for sensitive and accurate detection of Staphylococcus aureus. • Water-soluble UCNPs were prepared and modified with specific nuc ssDNA as fluorescent probes. • FRET based on the fluorescent probes and GOQDs was used. • Under the optimized condition, a 0.98 × 10−17 mol L−1 LOD was achieved. • It could be used for the detection of other pathogens in actual samples by replacing recognition probes and primers. [ABSTRACT FROM AUTHOR]

• A microfluidic device for fiber spinning based on chemical synthesis were designed. • Formation mechanism of ordered coil structure by the microfluidic device was analyzed. • Magnetic microspring with ordered helical structure were fabricated using this microfluidic spinning setup. The helical structure is one of the most intriguing structures in nature; such an ingenious structure can be found from macromolecules to macroscopic areas, and the fabrication of helical structures has attracted research interest from mechanisms to applications. However, the fabrication of helical microfiber still remains a big challenge. In this study, a coaxial microfluidic device was made to continuously and controllably fabricate helical hydrogel microfibers with flexible shape by simply adjusting the flowrates. Various experimental conditions that can influence the diameter (d), pitch (p) and amplitude (A) of these formed coiled fibers were discussed. For the first time, the effects of G/M ratio of the alginates on the microfiber coiling phenomenon were examined. Additionally, magnetically responsive helical fibers were synthesized, and it is envisioned that hydrogel helical structure microfibers are highly versatile in different area, such as micro sensors, soft actuators and medical applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A new N-oxide based and turn on fluorescent probe for Fe2+ was developed. • The probe possessed a high selectivity for Fe2+ among various biologically relevant species and fast rapid response. • Monitoring Fe2+ with TPM fluorescence imaging for the first time. Abstract Iron is an essential element for human body, involved in important biochemical processes in the body, especially in biological oxidation. Misregulation of iron levels in the cell is concerned with serious diseases. Here, a novel two photon and turn on NIR-fluorescent probe based ICT for detection of Fe2+ is first reported. The probe exhibited brilliant selectivity and excellent sensitivity (DL = 4.5 μM), rapid response (15 min) and "naked-eye colorimetric sensor" for monitoring of Fe2+. More importantly, the probe was successfully applied to real-time monitor Fe2+ in living cell through two-photon microscopy fluorescence imaging with excitation 680 nm. [ABSTRACT FROM AUTHOR]

We developed an ultrasensitive low-background chemiluminescence enzyme immunoassay (CLIA) for multiplex mycotoxin detection using silica-hydrogel photonic crystal microsphere (SHPCM) suspension arrays. The interspace of SHPCM was occupied by hydrogel material and retained the structure color of SPCM, which not only could encode microsphere carriers with their positions of reflection peaks or structure colors but reduce the non-specific protein adsorption and result in a low background signal. Comparison with SPCM and glass beads, SHPCM could provide the more wide dynamic detection linear range and lower background signal. The linear detection range was 0.0001–1 ng/mL, 0.001–10 ng/mL, and 0.0001–1 ng/mL for AFB1, FB1 and OTA, respectively. The recovery rates in rice, corn and wheat samples for AFB1, FB1 and OTA were between 74.96 ± 5.82%–104.87 ± 5.77%. The positive results detected by this method in 20 real cereal samples were confirmed by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The results indicate that the SHPCM suspension array can be used to high throughput and sensitive screening for multiplex mycotoxins in cereal samples. [ABSTRACT FROM AUTHOR]

Two main challenges for biosensors facing may be analytical sensitivity and selectivity. Ultra-highly specific protein molecularly imprinted polymers (MIPs) with characteristics of easy preparation, chemical stability, convenient assembly with transducer, offer unprecedented opportunities for high-performance recognition towards targets. A dual-responsive electrochemical biosensor was demonstrated, where integrated both artificial protein MIPs and natural hyaluronic acid (HA) probes into one flexible electrode to detect biomarker CD44. Their efficacy towards target of two types of probes were elucidated and contrasted. Dual-channel screen-printed electrodes (SPEs) were designed innovatively. As one responsive channel, protein MIPs were synthesized through a polymerization procedure between functional monomer of alginate gel, a biocompatible antifouling chemical, and template protein CD44. Natural HA probes were immobilized to produce the other responsive channel. Such binary channels realized highly sensitive and selective target quantifying with lower limit of detections (LODs) of 1.41 × 10−5 ng/mL for MIPs-based and 1.51 × 10−5 ng/mL for HA-based channels, attributing to superior specificity, antifouling property and biocompatibility of MIPs and HA, satisfying stability of SPEs, high sensitivity of electrochemical techniques. The dual-responsive strategy can be extended to other batched integration of functionalized materials and active biomolecules into electrochemical and electro-catalytic biosensors towards multiple components to monitor physical signs and diagnose human diseases. [Display omitted] • A dual-responsive biosensor based on artificial and natural probes was constructed. • A dual-channel screen-printed electrode was designed and manufactured innovatively. • Artificial protein imprinted probe was synthesized and contrasted with natural probe. • Binary channels achieved ultra-highly sensitive and selective detection towards CD44. • Binary channels realized target quantification in complex human serum. [ABSTRACT FROM AUTHOR]

Abstract: A highly sensitive integrated polarimetric interferometer biosensor with improved long-time stability and simple operation was prepared by using a novel prism-chamber assembly and an inexpensive waveguide made by sputtering a tapered nanometric layer of Ta2O5 on a single-mode glass waveguide. By comparing the measured refractive-index (RI) sensitivities with those simulated based on a four-layer homogeneous waveguide, both the equivalent thicknesses (T eq) for the tapered Ta2O5 layers and a severe dependence of RI sensitivity on T eq were obtained. Addition of 1g of water in 100g of a Chinese liquor (alcohol concentration=46% (v/v)) was easily detected by the sensor. Monitoring of anti-human IgG adsorption with a waveguide of T eq =31.99nm indicates that the antibody coverage required for inducing a phase-different change of Δϕ = π is less than 0.012 monolayer. The same waveguide presents a quasi-linear dependence of Δϕ on water temperature with the slope of d(Δϕ)/dT =−28.50°/°C to which the contribution by the thermo-optical effect of the waveguide is 4.24°/°C, equivalent to a liquid RI change of Δn c =1.41×10−5. The interferometer exhibits the promising potential for chemical and biological analyses because of its outstanding characteristics. [Copyright &y& Elsevier]

• Sequential electrospinning strategy is developed to fabricate an all-nanofiber actuator. • The actuator exhibits high sensitivity, ultrafast actuation time, and excellent repeatability. • Incorporation of interconnected pores greatly enhances the shape deformation. Humidity-responsive bilayered actuators which can dynamically change their shapes under humidity gradients, have recently motivated significant interest in a wide variety of emerging fields, including artificial muscles, intelligent sensors, and smart devices. However, this kind of actuators frequently suffer from slow responsiveness, prolonged actuating period, and small deformation, which is due to the dense structure hindering the diffusion of water molecules. Herein, we employ a simple programmable electrospinning approach to fabricate a highly porous polyvinyl alcohol/polyvinyl butyral (PVA/PVB) bilayered actuator for achieving excellent humidity-triggered deformation. Benefiting from the differential affinity of the two layers to water and the elaborately structural design, the porous bilayered actuator exhibits superior actuating performance in response to humidity gradient. Briefly, only 283 ms is needed for driving the shape change, and the whole deformation merely requires 10 s; besides, large bending amplitude with the curvature of 11.2 cm−1 is achieved, and the shape deformation process can be repeated at least 30 times without fatigue. Finally, we demonstrate the porous nanofibrous actuator can be used as artificial plants to perform opening and closing motions and a self-driven detector for monitoring humidity in real-time. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Preparation of surface-modified PLNPs (ZnGa 2 O 4 : Mn2+) with good luminescent property. • Design of luminescence resonance energy transfer DEHSPI-PLNPs sensing system for sensitive detection of CN−. • Successful application for bioimaging in living cells. Abstract Cyanide anion is an inhibitor of the enzyme cytochrome c oxidase in the fourth complex of the electron transport chain, and usually found in the membrane of the mitochondria of eukaryotic cells, thus exploration of novel analytical methodology for sensitive and accurate detection of cyanide ion in cells is vital and urgent. Herein, we successfully prepared and surface-modified ZnGa 2 O 4 :Mn2+ PLNPs with excellent afterglow properties, small size and preferable dispersibility. Furthermore, we report a rational design and fabrication of a functional PL nanoprobe based on luminescence resonance energy transfer (LRET), which for the first time demonstrates detection of cyanide ion without external illumination. The nanoprobe is composed of two main moieties: PLNPs with excellent afterglow properties as energy donor; and DEHSPI, a chromophore with tunable light absorption, as both energy acceptor and CN− recognition element. PL can be effectively quenched by the chromophores assembled on the surface of PLNPs through a LRET process and subsequently recovered upon the addition of CN−. Importantly, the persistent afterglow nature highlights the merits of employing PLNPs as energy donor to eliminate the background noise under in situ excitation. Moreover, the nanoprobe exhibits excellent analytical properties and low cytotoxicity for bio-imaging of CN− in living cells. [ABSTRACT FROM AUTHOR]

Graphical abstract Two-Photon Fluorescent Probe TP-1Bz was developed for dual-targeting ratiometric viscosity and peroxynitrite in living cells and tissue. Highlights • Two-photon fluorescent molecule TP-1Bz was designed with near infrared emission, water solubility and cell penetrability. • TP-1Bz showed good mitochondria targeting capability and high sensitivity to the viscosity change in mitochondria. • TP-1Bz proved to detect the exogenous and endogenous ONOO– in mitochondria, even in tissue samples of rat liver. Abstract The irregular viscosity and peroxynitrite (ONOO–) concentration in mitochondria would result in mitochondria disorders. However, fluorescent probes that can detect both of viscosity and peroxynitrite have not been explored. For this reason, a two-photon fluorescent molecule TP-1Bz was designed and synthesized in this work for the dual-ratiometric-imaging of viscosity and exogenous and endogenous ONOO– in mitochondria. Results indicated that TP-1Bz has two emissions at 407 nm and 650 nm respectively, their ratio (I650/I407) showed linear relationship to the viscosity of the media in the logarithmic plot, and its two-photon action cross-section (Φσ) at 880 nm was increased from 1.2 GM in aqueous solution to be 86.3 GM (72-fold) in 99% glycerol. With a good targeting capability to mitochondria, TP-1Bz allowed us to measure the average viscosity in the mitochidria of HepG2 cells (73.3 cp) and the mitochondria viscosity change upon the addition of ionpores. TP-1Bz also showed the high sensitivity to ONOO– (LOD close to 12.1 nM) in water/glycerol (2/3) solvent as well as the high selectivity over other ROS. With the advantages of its lower cytotoxicity, pH- and photo- stabilities, TP-1Bz was successfully employed for imaging ONOO– in living cells and even in tissue samples of rat liver through the monitoring the emission intensities of the blue and red channels. As the first example of two-photon ratiometric fluorescent probe for dual-imaging viscosity and peroxynitrite in mitochondria, TP-1Bz has great potential to be developed for clinical applications. [ABSTRACT FROM AUTHOR]

The bis-imidazolium salt 1,4-bis[ N -(9′-anthracenyl-methyl)imidazoliumyl]butane hexafluorophosphate ( L 1 H 2 ·(PF 6 ) 2 ) and its N -heterocyclic carbene (NHC) silver(I) macrometallocycle [(L 1 Ag) 2 ](PF 6 ) 2 ( 1 ) have been prepared and characterized. 18-Membered macrometallocycle of 1 is formed via two ligands ( L 1 ) and two silver(I) ions. The selective recognition of m -dinitrobenzene (DNB) using 1 as a host was studied on the basis of fluorescence titrations, 1 H NMR titrations, HRMS spectra and IR spectra. The results indicate that 1 can distinguish effectively m -dinitrobenzene with other aromatic compounds. [ABSTRACT FROM AUTHOR]

We design a novel high throughput photonic crystal microsphere (PHCM) suspension array for multiplex mycotoxins in cereal samples based on the aptamer fluorescence signal recovery. The hybridization duplex strand DNA from mycotoxin aptamer and anti-aptamer respectively labeled with fluorescence dye and quencher was immobilized on the carboxylated surfaces of PHCMs. When the corresponding mycotoxin targets bind to their aptamers, the fluorescence recovery signal intensity of PHCMs reported the concentration of mycotoxins. The different kinds of mycotoxins were distinguished by the structure colors of PHCMs. The fluorescence signal intensity on the PHCMs is nearly higher 100 times than that of solid glass beads. The detection system presents an ultrasensitive, high selectivity, and small volume reagent screening for multiplex mycotoxins with a dynamic linear detection range of 0.1 pg/mL–0.1 ng/mL for AFB1/OTA and 0.1 ng/mL–10 ng/mL for FB1 and a limit of detection (LOD) of 15.96 fg/mL, 3.96 fg/mL and 11.04 pg/mL for AFB1, OTA and FB1, respectively. The recovery rates in spiked cereal samples were well consistent with that of the traditional ELISA. The designed system provides a new high throughput aptamer-based suspension array for small molecule screening in parallel. [ABSTRACT FROM AUTHOR]

Glutamate decarboxylase antibody (GADA) and insulin autoantibody (IAA) are essential biomarkers for type 1 diabetes mellitus (T1DM). These islet autoantibodies are present in the serum of patients and are useful for the early diagnosis of T1DM. In this study, we developed a surface-enhanced Raman scattering (SERS)-based immunoassay for the detection of two T1DM-related autoantibodies, GADA and IAA. GADA and IAA are specifically captured by their antigens immobilized on the mercaptobenzoic acid (MBA)-functionalized silver substrates. They can be quantitatively detected based on the Raman frequency shifts of the cross-linker MBA. Combined with a 96-well plate, the immunoassay enabled a high-throughput analysis of the two biomarkers. The results suggest that the proposed method has significant potential for clinical application in rapid, sensitive, and high-throughput screening of T1DM. [Display omitted] • Both GADA and IAA were detected based on SERS frequency shifts. • The biosensor enables rapid, sensitive, and high-throughput screening of Type 1 diabetes. • The feasibility of using the proposed biosensor for clinical samples was validated in human serum. [ABSTRACT FROM AUTHOR]

Citri Reticulatae Pericarpium (CRP) is a medicinal and food homolog commonly used in Chinese medicine. The quality, price, and content of dihydroflavones (DHFs) and polymethoxyflavones (PMFs) in CRP are directly related to their origin. A novel, fast, and simple visual discrimination method for the origin of CRP is presented here. Al3+ and bovine serum albumin/thiosalicylic acid-modified Ag nanoclusters (BSA/TSA-AgNCs) were screened as fluorescent sensors for targeting DHFs and PMFs, respectively. After 60 batches of CRP extracts from different origins reacted with Al3+ or AgNCs sensors, three types of CRP origin could be discriminated accurately by the naked eye or using partial least squares discriminant analysis (PLSDA), according to the significant differences in fluorescence color. It showed a good discrimination effect when applied to filter-paper-based detection. The sensoring mechanism can be the DHFs in CRP form a complex with Al3+, which increases the molecular conjugation and structural rigidity, resulting in a fluorescence enhancement effect. PMFs are more likely to enter the BSA shell of AgNCs owing to hydrophobic interactions and transfer electrons with TSA modified on the surface of AgNCs, resulting in the photoinduced electron transfer (PET) effect and aggregation of TSA-AgNCs, which eventually leads to fluorescence quenching. [Display omitted] • A novel visual fluorescent sensing method for discrimination of CRP origins. • Al3+ and BSA/TSA-AgNCs were selected as sensors for DHFs and PMFs respectively. • CRC, CRD and CRB could be discriminated accurately by either naked eyes or PLSDA. • This method is easy, fast, accurate and instrument-free, suitable for on-site assay. [ABSTRACT FROM AUTHOR]

Melioidosis caused by Burkholderia pseudomallei (Bp) infection has high mortality in tropical and subtropical regions. A rapid and sensitive method for its detection is urgently needed. Herein, a ratiometric fluorescent sensor with dual recognition sites of target was designed for sensitive detection of Bp DNA. The sensor was constructed with a TAMRA-labeled DNA as probe, which could adsorb on polymer dots (Pdots) at acidic pH to produce TAMRA fluorescence at the excitation wavelength of Pdots via fluorescence resonance energy transfer (FRET). In the presence of target DNA, the trans-cleavage activity of CRISPR/Cas12a was activated with the dual recognition sites, which digested the probe DNA to weaken the FRET. With the fluorescence ratio of Pdots to TAMRA as the detection signal, a ratiometric fluorescent biosensing was thus achieved. This method with dual CRISPR/Cas12a trans-cleavage assisted signal enhancement showed a detectable range of target DNA from 1.0 pM to 10 nM, and could be successfully used to detect Bp DNA extract with a detection time of 40 min. The excellent performance such as high sensitivity, good specificity, acceptable accuracy and short analytical time along with convenient operation demonstrated its potential in clinic diagnosis of melioidosis. • A dual CRISPR/Cas12a trans-cleavage assisted signal enhancement strategy is proposed for biosensing of biomarker. • The proposed biosensing method based on ratiometric fluorescence has been used for detection of Burkholderia pseudomallei. • The proposed method shows a wide detection range with LOD of 1 pM and a detection time of 40 min with simple operation. • This proposed strategy possesses excellent performance and good extendability for target DNA analysis. [ABSTRACT FROM AUTHOR]

Novel fluorescent thioglycollic acid (TGA) surface-functionalized single-layered thickness structured MoS 2 nanosheets were purposely synthesized by a facile one-step hydrothermal treatment of using molybdenyl acetylacetonate, TGA and sodium sulfide as precursors. During the process of synthesis, we subtly solved the problem of the poor water solubility of the precursor molybdenyl acetylacetonate, and obtained thiolated single-layer MoS 2 nanosheet (TGA-MoS 2 ) with excellent water solubility and stable fluorescence property. The fluorescence of TGA-modified MoS 2 nanosheets was significantly suppressed in the presence of dopamine (DA), and a simple sensing system for highly selective, fast, direct detection of dopamine was established. Meanwhile, the present methodology has a wide detection range of 0.05 μΜ to 20 μΜ, a comparable detection limit of 27 nM and an extremely short response time of 3 min. To understand the fast response behavior, we tried effort to explain the interaction mechanisms between TGA-MoS 2 nanosheets and the quencher DA. Further research suggests that the possible mechanism might be the charge transfer (CT) by the stacking of MoS 2 layers through C O⋯H O hydrogen boding interaction, providing a fast fluorescence sensing platform for DA determination in urine and serum sample. [ABSTRACT FROM AUTHOR]

In this work, we firstly report a novel battery-triggered open wireless electrochemiluminescence (O-WL-ECL) sensing strategy based on the microfluidic cloth-based bipolar devices (μCBPDs). The carbon ink-screen-printing is used to fabricate the bipolar electrodes (BPEs) and driving electrodes on the cloth which is patterned with wax-screen-printed hydrophilic channels to create low-cost sensors ($0.011 per device) which can be powered with a rechargeable battery and read with an inexpensive, portable charge coupled device (CCD) camera. Moreover, the widely-used luminol/hydrogen peroxide (H 2 O 2 ) ECL reaction has been performed to illustrate the quantitative ability of the O-WL-ECL μCBPDs. Under optimized conditions, the μCBPDs can achieve the measurement of H 2 O 2 , with a linear range of 0.025–10 mM and a detection limit of 0.024 mM. Additionally, the determination of glucose can be carried out in the linear range from 0.025 mM to 10 mM, with a detection limit of 0.023 mM. It has been shown that the O-WL-ECL on μCBPDs has an acceptable sensitivity, stability and reproducibility. Finally, this simple and cost-effective device is successfully applied for the measurements of H 2 O 2 in milk and glucose in clinical urine and serum samples. Therefore, the proposed methodology could provide great promise in applications in many areas, and may facilitate the achievement of point-of-care testing. [ABSTRACT FROM AUTHOR]

Dengue caused by dengue virus (DENV) is a highly pathogenic viral disease. Early detection of pathogens is very important for patient treatment and pathogen control. This work designed a dual signal amplification strategy for sensitive fluorescent detection of DENV RNA. The dual signal amplification was achieved by using a target-triggered hybridization chain reaction (HCR) to connect multiplex proximity ligation activated CRISPR-Cas12a (pCRISPR-Cas12a). The HCR was triggered by the recognition of DENV RNA to a hairpin probe (H3), which led to a product to initiate the continuous hybridization of a couple of hairpins. Here one of the hairpins (H2) was designed to contain two domains (a and b), and domains a and b from two H2 formed a proximity ligation sequence (PLS) to connect the multiplex pCRISPR-Cas12a onto the HCR product, in which domain a activated the Cas12a, and domain b enhanced the enzymatic activity by about 5 times. Upon the enzymatic cleavage of single-stranded DNA labeled with a fluorophore and quencher at each end (ssDNA-FQ), a strong fluorescent signal was produced for DENV RNA analysis, which showed a linear range from 1 pM to 10 nM and a detection limit of 51 fM. The excellent performance of the proposed homogenous fluorescent assay with high sensitivity and superior accuracy endowed this strategy broad application prospects in clinical disease diagnosis. [Display omitted] • A universal fluorescence biosensing strategy was developed for highly sensitive detection of Dengue virus RNA. • The parallel connection of proximity sequence enhanced CRISPR-Cas12a was achieved through target-triggered HCR. • This proposed homogenous detection method showed a wide detection range and 50 fM-level detection limit. • This proposed strategy possesses good accuracy, high precision, and good extendability for target analysis. [ABSTRACT FROM AUTHOR]

• A highly efficient CTL sensor for acetone vapor coupled with UIO-66 as the preconcentrator was established. • A simple and low-cost home-made adsorption apparatus with UIO-66 was fabricated. • The proposed CTL sensing platform demonstrated advantages of high sensitivity, selectivity, and speediness. Metal-organic frameworks (MOFs) showed a significant sorption potential in the gas capture and preconcentration during recent years because of its super porosity. Herein, we fabricated a simple and inexpensive home-made adsorption apparatus based on UIO-66 as the preconcentrator, which was firstly coupled with a rapid cataluminescence (CTL) sensor to determine acetone vapor. The CTL emission was enhanced by 25 times after the preconcentration of UIO-66, indicating the UIO-66 preconcentrator could efficiently ameliorate sensitivity. As for the adsorption mechanism of UIO-66 for acetone molecules, we deduced that acetone molecules were preferentially located on the Zr clusters with high hydrophilicity. The proposed CTL sensor in combine with UIO-66 adsorption granted a detection limit of acetone down to 2.79 ppm, and demonstrated good selectivity, simplicity, rapidity, and recyclability. This study provides appealing perspectives of UIO-66 as the preconcentrator for the improvement of analytical performance, and the prospect of a miniaturized portable acetone sensor. [ABSTRACT FROM AUTHOR]