Search

Bacillus cereus is a Gram-positive endospore-forming foodborne pathogen that causes lethal food poisoning and significant economic losses, usually through biofilm- and endospore-induced recurrent cross- and postprocessing contamination. Due to the lack of critical inhibitory targets and control strategies, B. cereus biofilm contamination is a problem that urgently needs a solution. In this study, the antibacterial and antibiofilm activities of several natural potential bacterial quorum sensing (QS) interferers, a group of spice-originated monoterpenoids, were screened, and terpinen-4-ol effectively inhibited B. cereus growth and biofilm and spore germination with minimum growth inhibition and 50% biofilm inhibitory concentrations of 8 and 2 μmol/mL, respectively. FESEM/CLSM and phenotypic research illustrated that in addition to a decrease in the number of attached B. cereus cells, (+)-terpinen-4-ol also obviously reduced extracellular matrix synthesis, especially exopolysaccharides, and inhibited the swarming motility and protease activity of B. cereus. (+)-Terpinen-4-ol did not exert a significant effect on AI-2 signals in B. cereus. Accordingly, the B. cereus-produced interspecies QS signals diffusing signal factors (DSFs, C8-C15) and diketopiperazines (DKPs) were detected and identified here, which suppressed B. cereus biofilm formation in a concentration-dependent manner. (+)-Terpinen-4-ol significantly increased the levels of specific DSF and DKP signals in B. cereus and down-regulated the gene expression of some rpfB homologues in transcription level. Moreover, both DKPs and DSFs inhibited swarming motility and protease activity in B. cereus, while just the DSF signals 2-dodecenoic acid and 11-methyl-2-dodecenoic acid inhibited exopolysaccharide synthesis like (+)-terpinen-4-ol. In summary, B. cereus strains were found to produce nine DSF- and six DKP-type QS signaling molecules, which repressed B. cereus biofilm formation. (+)-Terpinen-4-ol was confirmed to be a promising antibacterial and antibiofilm agent against B. cereus upregulating DSFs and DKPs levels, and it could target the critical genes rpfB for DSFs turnover.

Mercury, as a global toxic pollutant, is easy to be accumulated in aquatic products and poses a great threat to human health. In this work, we proposed a mix-to-read, label-free, and robust assay for detecting mercury pollution in aquatic products by engineering a ratiometric-enhanced G-quadruplex probe. The transformation from the G-quadruplex to a hairpin-like structure allows us to confer a ratiometric and leveraged response to Hg2+, amplifying the signal-to-background ratio for Hg2+ detection. Hg2+ response was further improved by screening parallel- and antiparallel-, single-, and multiple-stranded G-quadruplex structures. Compared to the common aptamer probes, the ratiometric-enhanced G-quadruplex probe increased the sensitivity for Hg2+ detection by 4.7 times. This proposed sensing system allowed a simple and one-tube homogenous detection of Hg2+ at room temperature using a single unlabeled DNA sequence. Its application for Hg2+ detection in fish and shrimp conferred satisfactory recovery rates ranging from 98.5 to 105.9%. The label-free and mix-to-read assay is promising for the onsite detection of mercury pollution and facilitating food safety of aquatic products.

Mycotoxins are the most toxic component and pose a major threat to human health. Monitoring mycotoxins in living cells is essential for their toxicology research; however, tools for the live-cell imaging of mycotoxins remain unexplored. Herein, we proposed a conformation-resolved aptamer nanoprobe (cresAptamer), allowing us to image mycotoxins in living cells. cresAptamer endows a dual recognition mechanism: binding-induced detachment from nanocarriers and response of intrinsic G-quadruplex of aptamers. The dual recognition mechanism allows us to resolve conformations of aptamer probes corresponding to nonspecific binding and target binding, thus sufficiently supporting the specific identification of target molecules in a complex matrix. cresAptamer significantly improved the signal-to-background ratio for detecting ochratoxin A (OTA), thus allowing us to sensitively and robustly image ochratoxin A in living cells. cresAptamer would be a facile tool for dynamically investigating the toxicology of mycotoxins at the single-cell level.

Microfluidic paper-based analytical devices (µPADs) take the paper as a base material and integrate nanoscale microchannel on it for multiple detections. Its unique properties like low cost, portability, simple operation, and easy to save make it better than the traditional microfluidic chips. While designed originally for point-of-care medical diagnostics, µPADs have attracted the attention of many researchers in the fields of environmental monitoring, water quality, and food safety. The novelty of this paper is to present a detailed overview of µPADs for clinical applications. Firstly, a brief introduction to production methods, characteristics, and applications of these methods have been given. Secondly, the basic implementation, working principles, and corresponding performance of detection methods of clinical devices have been discussed, which enable the µPADs to detect biomarkers, human cells, bacteria, and viruses in a short time. Lastly, the factors that limit µPADs commercial applications, and their future research directions have also been briefly summarized.

The development of organic phase change materials (PCMs) with large energy storage capacity, high thermal conductivity, and satisfactory solar-thermal conversion performance is critical for large-scale solar energy utilization. Here, novel composite PCMs based on poly(ethylene glycol) (PEG), nanofibrillated cellulose (NFC), and graphene were successfully fabricated by impregnating PEG into PEG-grafted NFC/graphene hybrid aerogels (GA/NFC-g-PEG). The GA/NFC-g-PEG with three-dimensional interconnected porous structures well supported the PEG within the nanostructural frameworks and effectively prevented the leakage and diffusion of PEG above its melting point. Grafting of PEG onto NFC was performed to improve the affinity between PEG and NFC/graphene hybrid aerogels, which significantly increased the PEG loading capacity of the CNF-g-PEG/graphene aerogel and prevented the leakage of PEG. Differential scanning calorimetry result showed that the as-prepared composite PCMs possessed extremely high melting enthalpies ranging from 185.5 to 187.4 J/g. The hot stage-digital camera test and thermogravimetric analyses showed that the composite PCMs exhibited excellent form-stability and thermal stability. Moreover, the introduction of graphene significantly increased the thermal conductivity and solar-thermal conversion efficiency of the composite PCMs. In conclusion, the synthesized composite PCMs showed tremendous potential for thermal energy storage applications.

Organic phase change materials (PCMs) have attracted increasing attention in the solar energy utilization field for their large thermal energy storage density, appropriate phase transition temperat...

Excessive use of antibiotics in aquatic products is a serious problem for food safety and human health, and on-site detection of antibiotics is highly demanded. Herein, we proposed multivalence aptamer probes, allowing sensitive, label-free, and homogeneous detection of antibiotics in different aquatic products. Compared to commonly used aptamers, multivalence aptamer probes can provide multiple binding sites and a higher affinity for target molecules, and the iterative binding on different binding sites contributes to an amplified recognition effect, sharply increasing the response and sensitivity of aptamer probes. The 2-valence aptamer probes conferred a limit of detection of 0.097 nM for kanamycin detection, where it is estimated that their sensitivity is enhanced 12 times compared to 1-valence aptamer probes. Meanwhile, multivalence aptamer probes allowed us to specifically identify kanamycin among other antibiotics. It could detect kanamycin residual in aquatic products including river eel and puffer fish, as well as tap water with high precision. A multivalence design strategy of aptamer probes would significantly improve the detection performance of aptamers, facilitating the translation of aptamer for food safety control.

Impregnating organic phase change materials (PCMs) into cellulose-based aerogels is considered as an accessible and effective technology to prevent the liquid leakage issue due to the superior surface tension and capillary force. However, the poor solar-thermal conversion performance, high flammability, and low thermal conductivity still restrict the large-scale application of organic PCMs. Herein, two-dimensional (2D)-layered black phosphorus (BP) nanosheets having a superior photothermal effect were synthesized from a BP crystal through ultrasonication-assisted liquid exfoliation. Then, novel form-stable PCM composites (CBPCMs) were prepared by impregnating n-octacosane into cellulose nanofiber (CNF)/BP hybrid aerogels. The porous aerogels adequately supported the n-octacosane and prevented the liquid leakage issue. Differential scanning calorimetry (DSC) analysis demonstrated that the synthesized CBPCMs based on CNF/BP hybrid aerogels possessed extremely high n-alkane loading capacity and thermal storage density (247.0–251.6 J g−1). The incorporation of BP nanosheets into the aerogels considerably increased the thermal conductivity (89.0% increase) and solar-thermal conversion and storage efficiency (up to 87.6%) of the CBPCMs. Furthermore, with the increasing content of BP nanosheets in the aerogels, the heat release rate and total heat release of the CBPCMs decreased considerably, while the LOI value and char yield increased, thus revealing the significantly improved flame retardancy of the PCM composites. In conclusion, the CBPCMs show considerable potential in solar utilisation systems.

Strong rigidity, low thermal conductivity, and short of multi-driven capabilities of form-stable phase change materials (FSPCMs) have limited their practical utilization. Herein, we report a shape-adaptable FSPCM with the coinstantaneous light/electro-driven shape memory properties and light/electro-to-thermal energy storage performance. The FSPCM is fabricated by incorporating the poly(ethylene glycol) (PEG) into the cellulose nanofiber/graphene nanoplatelet (GNP) hybrid-coated melamine foam (CG@MF). The CG@MF/PEG FSPCMs show a good encapsulation effect, enhanced thermal conductivity, and large melting enthalpy (178.9 J g-1). Due to the high elasticity of MF and the excellent photothermal conversion and electrical conductivity of the GNP network, the CG@MF/PEG FSPCMs exhibit a remarkable light/electro-driven shape memory effect by activating the phase change process of PEG. Meanwhile, the CG@MF/PEG FSPCMs can effectively convert light or electric energy into heat energy and reposit the converted energy during the phase change process. Furthermore, the CG@MF/PEG FSPCMs possess excellent multiresponsive self-adhesion properties. A light-sensitive, shape-adaptable, and thermal-insulating container is further explored. This study provides routes toward the development of multiresponsive shape-adaptable FSPCMs for energy storage applications.

The development of organic phase change materials (PCMs) with good shape stability, superior photothermal conversion efficiency, and high thermal conductivity is critical for practical photothermal...

Superhydrophobic fireproof coatings have attracted considerable attention owing to their multifunctional applications in academic and industrial areas. In this work, a sustainable, superhydrophobic, and fire-resistant nanocoating based on polydopamine (PDA) was successfully fabricated, and its application to cotton was explored. The Fourier transform infrared and X-ray photoelectron spectra confirmed that the framework of APP@PDA nanocoating was successfully constructed of alternate layers. Remarkably, assessment of the thermal and flammability properties for the pristine and nanocoated cotton fabric demonstrated that APP@PDA-coated cotton fabric exhibited highly efficient flame-retardant performance reflected by 59.6% reduction in peak heat release rate and 25.7% reduction in total heat release by virtue of a 260 nm thick charring layer formed during burning. Besides, the nanocoated cotton fabric maintained its superhydrophobicity and retained its excellent water repellent properties after treating by dodecyl mercaptan. All these fascinating characteristics would boost this nanocoated cotton for high-performance application.

Four unsaturated fatty acid derivatives including three new pantheric acids (1–3), together with three known polyketides (5–7), were isolated from a culture broth of the marine-derived fungus Aspergillus sp. SCAU150. Their complete structures were determined by NMR and HRESIMS data analyses. The antifungal activity of the isolated compounds above was evaluated and 2 was found to show moderated activity toward the phytopathogenic fungus Fusarium solani bio-80814 with an inhibition zone diameter of 6 mm under 5 µg/disc.

Schisandrae Chinensis Fructus (SCF) was a Traditional Chinese Medicine (TCM) for protecting liver. However, underlying therapeutic mechanisms of SCF for drug-induced liver injury (DILI) by acetaminophen (APAP) are still unclear. This study aims to discover the potential regulation mechanisms of SCF in the treatment of DILI by APAP using the integrated network pharmacology, plasma metabolomics profiling with UPLC-Q-TOF-MS approach. The key targets in the shared pathways of network pharmacology and metabolomics were screened and experimentally validated by Quantitative Real-time PCR analysis. The results showed that SCF could exert excellent effects on DILI by APAP probably through regulating ErbB signaling pathway and Arachidonic acid metabolism pathway, which was reflected by the reduced gene expression of TNF-α, IL-6, IL-1β, COX-2 and EGFR, as well as the increased gene expression of Nrf2, HO-1, MDM2, MAPK8, SRC, PLD1, CYP2E1, CYP1A2, CYP3A1. This study systematically explored the pharmacological mechanisms of SCF in the treatment of DILI, meanwhile, metabolomics combine with network pharmacology approach might be a useful strategy for early diagnosis of DILI by APAP.

Staphylococcus aureus (S. aureus) causes serious food-borne diseases, and tools able to directly profile intact S. aureus would greatly facilitate food safety and public health. Herein, we proposed a biosensing platform for culture-independent and separation-free profiling S. aureus, thus allow us to directly detect intact S. aureus in complex samples. The binding protection effect of aptamer-cell complex was introduced to construct the aptasensor, and it allowed to eliminate the optimization of aptamer probe sequences. The proposed aptasensor, terms enzymatic cleavage aptasensor could achieve a sensitive (a detection limit of 64 CFU/mL) and broad-concentration quantification (dynamic range 102-107 CFU/mL) of S. aureus. Furthermore, it could specifically identify intact S. aureus in complex samples, and the quantifying of S. aureus was achieved in tap water, milk and porker with high precision. Therefore, enzymatic cleavage aptasensor could be a good candidate for on-site biosensing platform of S. aureus, as well as other pathogens by replacing the aptamer sequences.

Aflatoxin B1 (AFB1) contamination ranks as one of the most critical food safety issues, and assays for its on-site monitoring are highly demanded. Herein, we propose a label-free, one-tube, homogeneous, and cheap AFB1 assay based on a finely tunable dual-terminal stemmed aptamer beacon (DS aptamer beacon) and aggregation-induced emission (AIE) effects. The DS aptamer beacon structure could provide terminal protection of the aptamer probe against exonuclease I and confer specific and quick response to target AFB1. In comparison to the conventional molecule beacon structure, the stability of the DS aptamer beacon could be finely tuned by adjusting its two terminal stems, allowing for elaborately optimizing probe affinity and selectivity. By the utilization of an AIE-active fluorophore, which would be lighted up by aggregating to negatively charged DNA, AFB1 could be determined in a label-free manner. The proposed method could quantify AFB1 in one test tube using two unlabeled DNA strands. It has been succes...

Extensive efforts have been devoted to utilize cellulose fibers as reinforcement for poly(e-caprolactone) (PCL) to prepare fully biodegradable composites with enhanced mechanical properties, but unfortunately the improvement of strength is always at the sacrifice of toughness. In the current work, we have developed an efficient way to prepare poly(e-caprolactone)/functionalized cellulose nanofibers (PCL/f-NFC) nanocomposite, which is both strong and ductile. Large scale f-NFC was produced from microfibrillated cellulose (MFC) in one step through the synergy of mechanical and chemical actions derived from ball milling. The f-NFC with nanosized scale and tailored hydrophobicity is compatible with PCL, which leads to strong interfacial interaction between f-NFC and PCL and good dispersion of f-NFC in PCL. The tensile strength of this bionanocomposite undergoes a remarkable enhancement nearly 100% and elongation-at-break increases by 68% with extremely low f-NFC content as 0.1 wt%. Since both surface property and fiber size affect the performance of composites, original MFC, functionalized MFC (f-MFC) and cellulose nanofibers (NFC) without hydrophobic modification are also incorporated into PCL to make a systematic comparative study to identify the dominating factor influencing the performance. The overall results suggest that surface modification plays a dominant role at low fiber content, while nano-sized scale is much more beneficial at high fiber content. Most importantly, the synergistic effect of surface modification and nano-sized scale leads to significantly improved tensile properties across a wide range of fiber content.

We report a transcription aptasensor by using a light-up RNA aptamer. It allows for sensitive, label-free and culture-free detection of intact foodborne pathogens, and no separation, purification or enrichment processes are involved.

Viable pathogenic bacteria cause serious human diseases via systemic infections and food poisoning. Herein, we constructed a light-up RNA aptamer signaling-CRISPR-Cas13a assay enabling mix-and-read detection of viable pathogenic bacteria. Directly targeting pathogen RNAs via CRISPR-Cas13a allows precisely discriminating viable bacteria from dead bacteria. We introduced a light-up RNA aptamer, Broccoli, serving as the substate of activated CRISPR-Cas13a to monitor the presence of pathogen RNAs, eliminating the need to use chemically labeled RNA substrate. Sequentially, the assay allows a reverse transcription-free, nucleic acid amplification-free, and label-free quantification of RNA targets and viable pathogenic bacteria. It could detect as low as 10 CFU of Bacillus cereus and precisely quantify viable bacteria with a content ranging from 0% to 100% in 105 CFU total bacteria. The quantification of viable bacteria allows more accurately estimating the ability of B. cereus to spoil food. The RNA assay promises its use in point-of-use detection of viable pathogens and biosafety control.

In this study, a novel carbon dots (CDs) was prepared by using citric acid and 1,2-diaminobenzene as raw materials via hydrothermal reaction. The obtained CDs showed a fluorescence turn-off response to divalent copper ion (Cu2+) with high selectively and sensitively which can be observed by the naked eye. The distribution of CDs is spherical with an average diameter about 2.89 nm, as observed by scanning electron microscopy (TEM) which could easily pass through the cell membrane and can be successfully located in mitochondria. In addition, the CDs was successfully applied to imaging Cu2+ in HeLa cells and zebrafish owing to its excellent optical performance and low toxicity.

Cellulose films with excellent mechanical strength are of interest to many researchers, but unfortunately they often lack the ductility and water resistance. This work demonstrates an efficient and easily industrialized method for hydrophobic cellulose films made of modified microfibrillated cellulose (MFC). Prior to film fabrication, the simultaneous exfoliation and acylation of MFC was achieved through the synergetic effect of mechanical and chemical actions generated from ball milling in the presence of hexanoyl chloride. Largely enhanced tensile strength and elongation at break have been achieved (4.98MPa, 4.37% for original MFC films, 140MPa, 21.3% for modified ones). Due to hydrophobicity and compact structure, modified films show excellent water resistance and decreased water vapor permeability. Moreover, optical performance of modified films is also improved compared with the original MFC films. Our work can largely expand the application of this biodegradable resource and ultimately reduce the need for petroleum-based plastics.

In the field of polymer/graphene nanocomposites, massive production and commercial availability of graphene are essential. Exfoliation of graphite to obtain graphene is one of the most promising ways to large-scale production at extremely low cost. In this work we illustrate a facile strategy for mass production of few-layered (≤ 10) graphene (FLG) via the newly explored ball milling. The achieved FLG concentration was determined by UV/Vis spectroscopy. The formation of FLG was proved by measuring the flake thickness by atomic force microscopy (AFM). Further Raman spectral studies indicated that the crystal structure of exfoliated flakes was preserved satisfactorily during this shear-force dominating process. To increase the maximum concentration obtainable, it’s critical to make a good parameter assessment. N-methylpyrrolidone (NMP) was used as a dispersing medium and the effect of milling parameters was systematically and quantitatively investigated, thus providing a criterion to optimize the milling process. We established the optimal values for solvent volume and initial weight of graphite. As for milling time, the production of FLG was enhanced with continuous milling according to the power law, but not linearly with increasing milling time. Moreover, the possible mechanism involved in milling process was also explored. Our work provides a simple method for graphite exfoliation and has great potential for improving thermal and electrical conductivity of polymer composites in the fields of engineering.

The distribution of functional filler is known to have significant influence on various functionalities, yet, not been systematically investigated. Herein, we use a blends system based on PA12/PA6 containing SiC and low-temperature expandable graphite (LTEG) to study it. The effect of filler distribution in such blends on various functionalities including: thermal conductivity, electrical conductivity, and electromagnetic interference (EMI) shielding ability, has been systematically studied. Further study on altering filler distribution with polished PA6-LTEG and PA6-LTEG in different sizes reveals that, polished particle surface results in reduced electrical and thermal conductivity; and smaller particle size leads to enhanced electrical conductivity, thermal conductivity and EMI shielding ability. Finally, theoretical approach on thermal conductivity demonstrates that the system illustrates very effective contribution in thermal conductivity from large PA6-LTEG “filler” comparing to much smaller traditional fillers. Such study could provide a guideline for the processing of functional polymer composites.

Ammonium dibutyl dithiophosphate (ADD) is one of the most important flotation reagents in sulfide mineral processing, causing severe environmental pollution. In this study, natural pyrrhotite (NP)-activated peroxydisulfate (PDS) was applied to treat ADD, which can alleviate mine tailing problems and reduce the cost of treating mine wastewater. PDS can be efficiently activated by NP for ADD degradation, achieving complete ADD removal with 0.35 g/L NP and 1.0 mM PDS. The PDS activation not only occurred in solution but on the NP surface. Dissolved Fe2+, dissolved Fe3+, surface-bound Fe2+, and surface-bound Fe3+ had been undergoing interconversion as the degradation reaction proceed. The generated sulfate radicals and hydroxyl radicals synergistically remove ADD in the NP/PDS system over a wide pH range. The excess O2 might cause the transformation of S O 4 ∙ - to S O 3 ∙ - in the NP/PDS/ADD system. Based on the density functional theory (DFT) calculation and the identification of intermediates, a pathway of ADD degradation in the NP/PDS system is proposed.

Development of recyclable and self-repairing phase-change materials, which enable renewable energy storage and sustainable development, is critical for the efficient utilisation of solar energy. Hence, we herein fabricated form-stable, reversible cross-linked polyurethane phase-change materials composites (DPCM-x) with excellent recyclability, outstanding self-healing ability (93.1%) and superior photo-thermal conversion efficiency (87.9%). Furan-modified polydopamine particles (f-PDAPs), which serve as cross-linkers and photo-thermal fillers, were incorporated into maleimide-terminated polyurethane phase-change materials via a Diels–Alder (DA) reaction. Sunlight irradiation experiments revealed that f-PDAPs addition significantly improved the storage efficiency and photo-thermal conversion of DPCM-x thanks to the superior solar-to-thermal energy conversion performance of the f-PDAPs. Additionally, the existence of both reversible DA networks and f-PDAPs ensured that DPCM-x composites had excellent near-infrared- (NIR-) induced self-healing abilities, thermal-induced recyclable properties and solid-state plasticity. Meanwhile, the recovered DPCM-x composites could largely maintain their original mechanical properties (90.1%) and thermal energy storage capacity. Such cross-linked polyurethane PCM composites exhibited excellent self-healing properties under NIR irradiation. Due to their outstanding recyclability, interesting energy storage ability and form stability, they have enormous potential for applications in the fields of solar-to-thermal energy conversion and storage.

The thermal conductivity of expanded graphite (EG)/polymer composites is investigated in terms of polymer chain structures. The EG/polyphenylene sulfide (PPS) composite with a backbone of benzene rings shows the continuous highest thermal conductivity and the fastest rate of enhanced ratio at the same content. Then it is followed by EG/syndiotactic polystyrene (sPS) composites with side groups of regularly arranged benzene rings. The last are the EG/amorphous polystyrene (aPS) composites with side groups of randomly arranged benzene rings. Our results show that the chain structures of polymer matrices have a great influence on the interaction and crystallization of EG/polymer composites, which leads to the different thermal behavior. More precisely, the strong π–π interaction between EG and polymer, the nucleation of crystal at the interface of EG/polymer and the relatively rich EG content in the amorphous phase are benefits to the enhancement of thermal conductivity. These factors are proved to be extremely important for the design of high thermally conductive composites in the fields of science and engineering.

In recent decades, great efforts have been devoted to prepare materials with enhanced thermal conductivity due to the growing interest in thermal conductive materials. Herein, we illustrate a facile strategy to improve the thermal conductivity of polyvinylidene fluoride/expanded graphite (PVDF/EG) composites by pre-treatment of EG via ball milling. Before incorporating EG into PVDF via conventional melt processing, EG powders were treated by shear-force-dominated ball milling. In this way, the loose and porous vermicular structure of EG could be effectively destroyed and exfoliated to graphite nanosheets (GNSs). As a result, the PVDF/GNSs composites show improved thermal conductivity owing to their larger specific surface area. With the filler content fixed at 15 wt%, the thermal conductivity of treated PVDF/GNSs composites can reach 1.29 W m−1 K−1, 42.5% higher than that of PVDF/EG (0.90 W m−1 K−1). Moreover, the electromagnetic interference (EMI) shielding property and tensile strength of PVDF/CNSs composites are also remarkably improved. Our work proves to be a simple and easily industrialized method for EG treatment which has great potential for improving the thermal conductivity of polymer composites in lighting devices and electromagnetic shielding applications.

Aggregation-induced emission (AIE) dyes are promising for labeling nucleic acid probes. Aptamer is one of the most appealing nucleic acid probes, and may enable to output signal response to target molecules by the direct use of single aptamer sequence. However, the concise sensing platform is often suffered from low sensitivity. In response, by the adoption of AIE dyes, we propose an intrinsic conformation response-leveraged aptamer probe (iconAptamer) for aflatoxin B1 (AFB1) detection. The design strategy lies in the synergetic utilization of AIE and fluorescence resonance energy transfer (FRET) effects. AIE dyes confer a much higher sensitivity for monitoring the response of aptamer towards AFB1 compared to traditional DNA intercalation dyes. FRET process between AIE dyes and the terminal-labeled fluorophore would induce a distance effect in the structure-switching process, further leveraging the response signal. Consequently, the sensitivity of the aptamer probe was dramatically improved by over 2 orders. IconAptamer allowed to mix-to-read detection of AFB1 contaminations at room temperature. The application of iconAptamer for AFB1 detection in food and environmental samples has been demonstrated, with recovery rates of 91.8%–111.1%. IconAptamer would provide a simple, fast, convenient, and cost-effective platform for food safety control and environmental monitoring by broadening the target species.

Aggregation-induced emission (AIE) dyes now serve as powerful tools for fluorescence analysis and biological imaging due to their light-up property in the aggregated state. Herein, we proposed an AIE dye-based aptasensor, enabling label-free and turn-on detection of mycotoxin. The positively charged AIE dyes would confer high-affinity to negatively charged aptamers and be lighted up by the aggregation process of dye molecules. Attributed to the resistance of ochratoxin A (OTA)-binding aptamer complex to enzyme digestion, label-free analysis of OTA could be realized via the synergetic utilization of AIE dyes and enzymatic digestion process. The digestion process could contribute to a signal to background ratio (S/B) of 1.71 for OTA detection. Remarkably, the adoption of AIE dyes would lead to a dramatic enhancement of over 104.5% of S/B compared to conventional nucleic acid dyes, thus favoring the sensitivity of the aptasensor. Only one aptamer sequence was involved in the assay, thus avoiding the complex structure design of aptamer probes. The AIE dye-based aptasensor could confer a limit of detection of 0.4 ng/mL for OTA detection. Besides, it exerted remarkable specificity for identifying OTA, and has been successfully applied for OTA analysis in wine and coffee. AIE dyes would be a compelling candidate in biohazard screening filed, and the proposed aptasensor would potentially provide a universal platform for on-site detection of food and environment contaminations.

Printed-electronics inks belong to a class of novel functional conductive inks that can be used to form high-precision conducting lines or circuits on various flexible substrates. Previous studies have reported conductive inks produced by the reduction and membrane separation method for use in flexible devices. However, it remains a challenge to synthesize conductive inks with high electrical properties at low sintering temperatures, which restricts their range of applications. Herein, we prepare inkjet-printed patterns of conductive inks consisting of Ag nanohexagonal platelets (AgNHPs) as the main component and containing graphene (GE) in different contents. It is found that GE improves the electrical conductivity of the patterns when sintering is done at relatively low temperatures. For instance, when the GE content is 0.15 mg ml(-1), the resistivity is the lowest. When sintering is done at 150 °C, the resistivity (2.7 × 10(-6) Ω · cm) of the GE-AgNHPs conductive ink (GE: 0.15 mg ml(-1)) is 14% of that of the AgNHPs conductive ink; on the other hand, after sintering at 50 °C, this ratio is 2%. It is also found that, with the increase in GE content, the resistivity of the GE-AgNHPs conductive ink increases. This study on GE-AgNHPs conductive inks sintered at low temperatures should further the development of flexible touch screens.