Detection and simultaneous imaging of acrylamide, miR-21 and miR-221 based on multicolor aggregation-induced emission nanoparticles and DNAzyme walker.

Acrylamide (AA) in heat-processed foods has emerged as a global health problem, mainly carcinogenic, neurotoxic, and reproductive toxicity, and an increasing number of researchers have delved into elucidating its toxicological mechanisms. Studies have demonstrated that exposure of HepG2 by AA in a range of concentrations can induce the upregulation of miR-21 and miR-221. Monitoring the response of intracellular miRNAs can play an important role in unraveling the mechanisms of AA toxicity. Here, multicolor aggregation induced emission nano particle (AIENP) probes were constructed from three AIE dyes for simultaneous imaging of intracellular AA and AA-induced miR-21/miR-221 by combining the recognition function of AA aptamers and the signal amplification of a DNAzyme walker. The surface of these nanoparticles contains carboxyl groups, facilitating their linkage to a substrate chain modified with a fluorescent quencher group via an amide reaction. Optimization experiments were conducted to determine the optimal substrate-to-DNAzyme ratio, confirming its efficacy as a walker for signal amplification. Sensitive detection of AA, miR-21 and miR-221 was achieved in extracellular medium, with detection limits of 0.112 nM for AA, 0.007 pM and 0.003 pM for miR-21 and miR-221, respectively, demonstrating excellent selectivity. Intracellularly, ZIF-8 structure collapsed, releasing Zn2+, activating DNAzyme cleavage activity, and the fluorescence of multicolor AIENPs within HepG2 cells gradually recovered with increasing stimulation time (0-12 h) and concentrations of AA (0-500 µM). This dynamic response unveiled the relationship between AA exposure and miR-21/miR-221 expression, further validating the carcinogenicity of AA.

Dual pH- and ATP-Responsive Antibacterial Nanospray: On-Demand Release of Antibacterial Factors, Imaging Monitoring, and Accelerated Healing of Bacteria-Infected Wounds under NIR Activation.

The prevalence of pathogenic bacterial infections with high morbidity and mortality poses a widespread challenge to the healthcare system. Therefore, it is imperative to develop nanoformulations capable of adaptively releasing antimicrobial factors and demonstrating multimodal synergistic antimicrobial activity. Herein, an NIR-activated multifunctional synergistic antimicrobial nanospray MXene/ZIF-90@ICG was prepared by incorporating ZIF-90@ICG nanoparticles onto MXene-NH2 nanosheets. MXene/ZIF-90@ICG can on-demand release the antimicrobial factors MXenes, ICG, and Zn2+ in response to variations in pH and ATP levels within the bacterial infection microenvironment. Under NIR radiation, the combination of MXenes, Zn2+, and ICG generated a significant amount of ROS and elevated heat, thereby enhancing the antimicrobial efficacy of PDT and PTT. Meanwhile, NIR excitation could accelerate the further release of ICG and Zn2+, realizing the multimodal synergistic antibacterial effect of PDT/PTT/Zn2+. Notably, introducing MXenes improved the dispersion of the synthesized antimicrobial nanoparticles in aqueous solution, rendering MXene/ZIF-90@ICG a candidate for application as a nanospray. Importantly, MXene/ZIF-90@ICG demonstrated antimicrobial activity and accelerated wound healing in the constructed in vivo subcutaneous Staphylococcus aureus infection model with NIR activation, maintaining a favorable biosafety level. Therefore, MXene/ZIF-90@ICG holds promise as an innovative nanospray for adaptive multimodal synergistic and efficient antibacterial applications with NIR activation.

Dual-mode aptasensor based on P-CeO2NR@Mxene and exonuclease I-assisted target recycling for malachite green detection.

Malachite green (MG) has been illicitly employed in aquaculture as a parasiticide, however, its teratogenic and carcinogenic effects pose a significant human health threat. Herein, a dual-mode colorimetric and electrochemical aptasensor was fabricated for MG detection, capitalizing on the robust catalytic and peroxidase-like activity of P-CeO2NR@Mxene and good capture efficiency of a tetrahedral DNA nanostructure (TDN) designed with multiple aptamers (m-TDN). P-CeO2NR@Mxene-modified complementary DNA (cDNA) served as both colorimetric and electrochemical probe. m-TDN was attached to AuE to capture MG and P-CeO2NR@Mxene/cDNA. The superior aptamer and MG binding to cDNA regulated signals and enabled precise MG quantification. The further introduced Exo I enabled aptamer hydrolysis, releasing MG for further binding rounds, allowing target recycling amplification. Under the optimal conditions, the aptasensor reached an impressively low detection limit 95.4 pM in colorimetric mode and 83.6 fM in electrochemical mode. We believe this dual-mode approach holds promise for veterinary drug residue detection.

Spatiotemporal ATF3 Expression Determines VSMC Fate in Abdominal Aortic Aneurysm.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a catastrophic disease with little effective therapy, likely due to the limited understanding of the mechanisms underlying AAA development and progression. ATF3 (activating transcription factor 3) has been increasingly recognized as a key regulator of cardiovascular diseases. However, the role of ATF3 in AAA development and progression remains elusive. METHODS: Genome-wide RNA sequencing analysis was performed on the aorta isolated from saline or Ang II (angiotensin II)-induced AAA mice, and ATF3 was identified as the potential key gene for AAA development. To examine the role of ATF3 in AAA development, vascular smooth muscle cell-specific ATF3 knockdown or overexpressed mice by recombinant adeno-associated virus serotype 9 vectors carrying ATF3, or shRNA-ATF3 with SM22α (smooth muscle protein 22-α) promoter were used in Ang II-induced AAA mice. In human and murine vascular smooth muscle cells, gain or loss of function experiments were performed to investigate the role of ATF3 in vascular smooth muscle cell proliferation and apoptosis. RESULTS: In both Ang II-induced AAA mice and patients with AAA, the expression of ATF3 was reduced in aneurysm tissues but increased in aortic lesion tissues. The deficiency of ATF3 in vascular smooth muscle cell promoted AAA formation in Ang II-induced AAA mice. PDGFRB (platelet-derived growth factor receptor ß) was identified as the target of ATF3, which mediated vascular smooth muscle cell proliferation in response to TNF-alpha (tumor necrosis factor-α) at the early stage of AAA. ATF3 suppressed the mitochondria-dependent apoptosis at the advanced stage by upregulating its direct target BCL2. Our chromatin immunoprecipitation results also demonstrated that the recruitment of NFκB1 and P300/BAF/H3K27ac complex to the ATF3 promoter induces ATF3 transcription via enhancer activation. NFKB1 inhibitor (andrographolide) inhibits the expression of ATF3 by blocking the recruiters NFKB1 and ATF3-enhancer to the ATF3-promoter region, ultimately leading to AAA development. CONCLUSIONS: Our results demonstrate a previously unrecognized role of ATF3 in AAA development and progression, and ATF3 may serve as a novel therapeutic and prognostic marker for AAA.

Sensitive SERS aptasensor for histamine detection based on Au/Ag nanorods and IRMOF-3@Au based flexible PDMS membrane.

BACKGROUND: Histamine is a kind of biogenic amine with strong toxicity and potential carcinogenicity. Many traditional methods of detecting histamine have the disadvantages of cumbersome detection steps, expensive equipment, and high professional requirements for staff. In contrast, SERS has become the preferred method for quantitative analysis of histamine because of rich fingerprint information, rapidity and economy. However, most of SERS substrates still have technical problems, such as poor stability, low sample collection rate, and detection efficiency. Therefore, there is a great need for new strategies to develop high-performance SERS substrates based sensors. RESULTS: In our study, a sensitive SERS aptasensor for the detection of histamine was synthesized. The assembly was formed between IRMOF-3@Au/PDMS (flexible SERS substrate) and AuNR-DTNB@Ag-HA apt (Raman signal probe with both the target capture ability) via π-π stacking interaction from HA aptamer and IRMOF-3. Consequently, the SERS signal of the assembly derived from DTNB reached highest due to the synergistic enhancement effect by AuNR@Ag and IRMOF-3@Au. Meanwhile, HA aptamer can specifically capture histamine, therefore histamine addition competitively bound to the probe, leading to a corresponding decrease in the DTNB signal value on the SERS substrate. The SERS intensity at 1331 cm-1 presented a good linear relationship towards the logarithmic value of histamine concentrations ranging from 0.0001 mg/L to 400 mg/L (R2 = 0.990) with the LOD of 3.6 × 10-5 mg/L. Furthermore, the application in wine samples demonstrated the accuracy and applicability of the developed sensor. SIGNIFICANCE: This method effectively improves substrate stability, detection sensitivity and signal response immediacy to amplify the SERS sensor, thus satisfying the histamine detection requirements of various systems. According to this aptasensor design, our strategy can be extended to create other MOF-based SERS substrates for accurately detecting relative targets to ensure food safety.

Detection of acrylamide in food based on MIL-glucose oxidase cascade colorimetric aptasensor.

BACKGROUND: Maillard reaction involves the polymerization, condensation, and other reactions between compounds containing free amino groups and reducing sugars or carbonyl compounds during heat processing. This process endows unique flavors and colors to food, while it can also produce numerous hazards. Acrylamide (AAm) is one of Maillard's hazards with neurotoxicity and carcinogenicity, these effects can trigger mutations and alternations in gene expression in human cells and accelerate organ aging. An accurate and reliable acrylamide detection method with high sensitivity and specificity for future regulatory activities is urgently needed. RESULTS: Herein, we constructed a colorimetric aptasensor with the hybridization of MIL-glucose oxidase (MGzyme)-cDNA and magnetic nanoparticle-aptamer (MNP-Apt) to specifically detect AAm. The incorporation of MB-Apt and AAm released MGzyme-cDNA in the supernatant, took the supernatant out, with the addition of glucose and TMB, MGzyme would oxidize glucose, the resulting •OH facilitated the oxidation of colorless TMB to blue ox-TMB. The absorbance value at 652 nm, which indicates the characteristic absorption peak of ox-TMB, exhibited a proportion to the concentration of AAm. MGzyme avoided the addition of harmful intermediate H2O2 and created an acid microenvironment for the catalytic reaction. MNP-Apt possessed the advantages of high specificity and simplified separation. Under optimal conditions, this method displayed a linear range of 0.01-100 µM with the limit of detection of 1.53 nM. With the spiked analysis data cross-verified by ELISA kit, this aptasensor was proven to specifically detect AAm at low concentrations. SIGNIFICANCE: This colorimetric aptasensor was the integration of aptamer and the enzyme-cascade system, which could broaden the applicable range of enzyme-cascade system, break the limits of specific detection of substrates, eliminate the need for harmful intermediates, improve the reaction efficiency, implement the specific detection, whilst enabling the accurate detection of AAm. Given these remarkable performances, this method has shown significant potential in the field of food safety inspection.

Study of four polyphenol-Coregonus peled (C. peled) myofibrillar protein interactions on protein structure and gel properties.

The effects of four polyphenols-chlorogenic acid (CA), gallic acid (GA), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) on the structure, gel properties, and interaction mechanisms of myofibrillar protein (MP) were studied. The changes in MP structure with polyphenols were analyzed using circular dichroism. The ultraviolet and fluorescence spectra and thermodynamic analysis indicated that the type of binding between the four polyphenols with the MP was static quenching of complex formation. GA had a more pronounced effect on improving MP gel properties. Finally, molecular docking determined that the affinity of the protein with the four polyphenols was in the order EGCG > ECG > CA > GA, with the main interaction force being hydrophobic interactions and hydrogen bonding, but hydrogen bonding dominates the interaction between GA and the protein. The findings illuminate the mechanism of MP binding to different polyphenols and facilitate the study of polyphenol-protein properties.

A colorimetric sensor array based on nanoceria crosslinked and heteroatom-doped graphene oxide nanoribbons for the detection and discrimination of multiple pesticides.

Nanozymes have demonstrated high potential in constructing colorimetric sensor array for pesticides. However, rarely array for pesticides constructed without bio-enzyme were reported. Herein, nanoceria crosslinked graphene oxide nanoribbons (Ce-GONRs) and heteroatom-doped graphene oxide nanoribbons (Ce-BGONRs and Ce-NGONRs) were prepared, demonstrating excellent peroxidase-like activities. A colorimetric sensor array was developed based on directly inhibiting the peroxidase-like activities of the above three nanozymes, which realized the discrimination and quantitative analysis of six pesticides. In the presence of pesticides including carbaryl (Car), fluroxypyr-mepthyl (Flu), thiophanate-methyl (Thio), thiram (Thir), diafenthiuron (Dia) and fomesafen (Fom), the peroxidase-like activities of three nanozymes were inhibited to different degrees, resulting in different fingerprint responses. The six pesticides in the concentration range of 0.1-50 µg/mL and two pesticides mixtures at varied ratios could be detected and discriminated, and minimum detection limit for pesticides was 0.022 µg/mL. In addition, this sensor array has been successfully applied for pesticides discrimination in lake water and apple samples. This work provided a new strategy of constructing simple and sensitive colorimetric sensor array for pesticides based on directly inhibiting the catalytic activities of nanozymes.

Universal Near-Infrared Fluorescent Nanoprobes for Detection and Real-Time Imaging of ATP in Real Food Samples, Living Cells, and Bacteria.

Adenosine triphosphate (ATP), an essential metabolite for active microorganisms to maintain life activities, has been widely regarded as a marker of cell activity and an indicator of microbial contamination. Herein, we designed two near-infrared (NIR) fluorescent nanoprobes named CYA@ZIF-90 and CYQ@ZIF-90 by encapsulating the NIR dye CYA/CYQ in ZIF-90 for the rapid detection of ATP. Between them, nanoprobe CYA@ZIF-90 can achieve higher NIR emission (702 nm) and rapid detection (2 min). Based on the superior spatiotemporal resolution imaging of ATP fluctuations in living cells, the applicability of CYA@ZIF-90 for imaging and detection of ATP in living bacteria was explored for the first time. The nanoprobe indirectly realizes the quantitative detection of bacteria, and the detection limit can be as low as 74 CFU mL-1. Therefore, the prepared nanoprobe is expected to become a universal ATP sensing detection tool, which can be further applied to evaluate cell apoptosis, cell proliferation, and food-harmful microbial control.

A Versatile Strategy of Designing Gold Nanoparticle-cDNA Nanoprobes in Developing Aptamer-Based Lateral Flow Assay for Small-Molecule Detection.

Aptamer-based lateral flow assay (Apt-LFA) has shown promising applications for small-molecule detection. However, the design of the AuNP (gold nanoparticle)-cDNA (complementary DNA) nanoprobe is still a big challenge due to the moderate affinity of the aptamer to small molecules. Herein, we report a versatile strategy to design a AuNPs@polyA-cDNA (poly A, a repeat sequence with 15 A bases) nanoprobe for small-molecule Apt-LFA. The AuNPs@polyA-cDNA nanoprobe contains a polyA anchor blocker, complementary DNA segment to DNA on the control line (cDNAc), partial complementary DNA segment with aptamer (cDNAa), and auxiliary hybridization DNA segment (auxDNA). Using adenosine 5'-triphosphate (ATP) as a model target, we optimized the length of auxDNA and cDNAa and achieved a sensitive detection of ATP. In addition, kanamycin was used as a model target to verify the universality of the concept. Therefore, this strategy can be easily extended to other small molecules; therefore, high application potential in Apt-LFAs can be envisaged.

A gold nanoflower based dual mode aptasensor for aflatoxin B1 detection using SERS and fluorescence effect simultaneously.

Aflatoxin B1 (AFB1) is usually the major aflatoxin produced by toxigenic strains and has been identified the most potent natural carcinogen. Here, a SERS/fluorescence dual-mode nanosensor has been designed while gold nanoflowers (AuNFs) was used as substrate for the detection of AFB1. AuNFs exhibited excellent SERS enhancement effect as well as the good fluorescence quenching effect which made the dual signal detection possible. First, the surface of AuNFs was modified with AFB1 aptamer via Au-SH group. Then, the complementary sequence functionalized with Cy5 (the signal molecule) was attached to AuNFs based on the base complementary pairing principle. On this case, Cy5 was close to AuNFs, the SERS intensity was greatly enhanced and the fluorescence intensity was quenched. After incubation with AFB1, the aptamer was preferentially combined to its target AFB1. Thus, the complementary sequence detached from AuNFs which caused the SERS intensity of Cy5 decreased while its fluorescence effect recovered. Then, the quantitative detection was realized with two optical properties. The LOD was calculated to be 0.03 ng/mL. It was a convenient and fast detection method which expanded the application of nanomaterials based multi-signal simultaneous detection.

SERS-fluorescence dual-mode nanoprobe for the detection and imaging of Bax mRNA during apoptosis.

A dual-mode nanoprobe was constructed to detect Bax messenger RNA (mRNA), consisting of gold nanotriangles (AuNTs), a Cy5-modified recognition sequence, and a thiol-modified DNA sequence. Bax mRNA is one of the key pro-apoptotic factors in the apoptosis pathway. Raman enhancement and fluorescence quenching of the signal group Cy5 were performed using AuNTs as substrates. The thiol-modified nucleic acid chain is partially complementary to the Cy5-modified nucleic acid chain to form a double strand and is linked to the AuNTs by the Au-S bond. When Bax mRNA is present, the Cy5-modified strand specifically binds to it to form a more stable duplex, making Cy5 far away from AuNTs, and SERS signal is weakened while fluorescence signal is enhanced. The nanoprobe can be used for the quantitative detection of Bax mRNA in vitro. Combined with the high sensitivity of SERS and the visualization of fluorescence, this method has good specificity and can be used for in situ imaging and dynamic monitoring of Bax mRNA during deoxynivalenol (DON) toxin-induced apoptosis of HepG2 cells. DON plays a pathogenic role mainly by inducing cell apoptosis. The results confirmed that the proposed dual-mode nanoprobe has good versatility in various human cell lines.

Emerging chitosan grafted essential oil components: A review on synthesis, characterization, and potential application.

Chitosan is a green, low-cost natural polymer material. The bioactivity of chitosan can be enhanced by coupling with essential oil chemicals, which can broaden the range of applications. Essential oil-chitosan (EOCS), the chitosan modified by essential oil components, which has been widely used as a multi-perspective in numerous filed of food and life in recent years. Herein, the synthesis, characterization, and recent application of EOCS are reviewed. Synthetic methods include 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated modification, free radical-induced modification, enzyme-catalyzed modification, bromide-mediated modification, and method of forming Schiff-base directly. The successful synthesis of derivatives can be demonstrated by UV, FT-IR, TLC, and NMR. EOCSs can be used as preservative coatings, packaging materials, and antibacterial agents in the food industry, as well as drug delivery and wound treatment in biomedicine. In addition, EOCSs are also used in other industries, such as environmental protection, metal corrosion inhibition, as well as plant pest control.

Accelerated CRISPR/Cas12a-based small molecule detection using bivalent aptamer.

CRISPR/Cas holds great promise for biosensing applications, however, restricted to nucleic acid targets. Here, we broaden the sensing target of CRISPR/Cas to small molecules via integrating a bivalent aptamer as a recognition component. Using adenosine 5'-triphosphate (ATP) as a model molecule, we found that a bivalent aptamer we selected could shorten the binding time between the aptamer and ATP from 30 min to 3 min, thus dramatically accelerating the detection of ATP. The accelerated bivalent aptamer binding to ATP was mainly ascribed to the extended conformation of the aptamer, which was stabilized through linking with a 5 T bases connector on specific loops of the monovalent aptamer. To facilitate on-site detection, we integrated lateral flow assay (LFA) with the CRISPR/Cas sensing strategy (termed BA-CASLFA) to serve as a visual readout of the presence of ATP. In addition, in the CASLFA platform, due to the unique characteristics of LFA, the thermal step of Cas12a inactivation can be omitted. The BA-CASLFA could output a colorimetric "TURN ON" signal for ATP within 26 min, which could be easily discriminated by the naked eye and sensitively quantified by the portable reader. Furthermore, we showed the versatility of BA-CASLFA for detecting kanamycin using a kanamycin bivalent aptamer obtained through the same design as the ATP bivalent aptamer. Therefore, this strategy is amenable to serve as a general sensing strategy for small molecular targets. The above work opened a new way in developing CRISPR-based on-site sensors for clinic diagnosis, food safety, and environmental analysis.

Split aptamer remodeling-initiated target-self-service 3D-DNA walker for ultrasensitive detection of 17ß-estradiol.

DNA walker machines, as one of the dynamic DNA nanodevices, have attracted extensive interest in the field of analysis due to their inherent superiority. Herein, we reported a split aptamer remodeling-initiated target-self-service 3D-DNA walker for ultrasensitive, specific, and high-signal-background ratio determination of 17ß-estradiol (E2) in food samples. Two split probes (STWS-a and STWS-b) were rationally designed that can undergo structural reassembled to serve as walking strands (STWS) under the induction of the target. Meanwhile, an intact E6-DNAzyme region was formed and activated at the tail of STWS. The activated E6-DNAzyme then continuously drives the 3D-DNA walker for signal amplification and specific detection of E2. Under optimal conditions, the proposed DNA walker-based biosensor exhibited excellent linearity in the range of 1 pM to 50 nM with a low limit of detection (LOD) of 0.28 pM, and good precision (2.7%) for 11 replicate determinations of 1 nM of E2. Furthermore, the developed DNA walker-based biosensor achieved excellent sensitive analysis of E2 in the complex food matrix with recoveries of 95.6-106.5%. This newly proposed split aptamer-based strategy has the advantages of ultrasensitive, high signal-to-background ratio, and high stability. Noteworthy, the successful operation of the DNA walker initiated by the split aptamer expands the principles of DNA walker design and provides a universal signal amplification platform for trace analysis.

Protective Effects of Ferulic Acid on Deoxynivalenol-Induced Toxicity in IPEC-J2 Cells.

Deoxynivalenol (DON), a mycotoxin that contaminates crops such as wheat and corn, can cause severe acute or chronic injury when ingested by animals or humans. This study investigated the protective effect of ferulic acid (FA), a polyphenolic substance, on alleviating the toxicity induced by DON (40 µM) in IPEC-J2 cells. The experiments results showed that FA not only alleviated the decrease in cell viability caused by DON (p < 0.05), but increased the level of superoxide dismutase (SOD) (p < 0.01), glutathione peroxidase (GSH-Px), (catalase) CAT and glutathione (GSH) (p < 0.05) through the nuclear factor erythroid 2-related factor 2 (Nrf2)-epoxy chloropropane Kelch sample related protein-1 (keap1) pathway, and then decreased the levels of intracellular oxidative stress. Additionally, FA could alleviate DON-induced inflammation through mitogen-activated protein kinases (MAPKs) and nuclear factor kappa-B (NF-κB) pathways, down-regulated the secretion of interleukin-6 (IL-6) (p < 0.0001), interleukin-8 (IL-8) (p < 0.05), interleukin-1ß (IL-1ß), interferon-γ (IFN-γ) and further attenuated the DON-induced intracellular apoptosis (10.7% to 6.84%) by regulating the expression of Bcl2-associated X protein (Bax) (p < 0.0001), B-cell lymphoma-2 (Bcl-2) (p < 0.0001), and caspase-3 (p < 0.0001). All these results indicate that FA exhibits a significantly protective effect against DON-induced toxicity.

Photodynamic chitosan functionalized MoS2 nanocomposite with enhanced and broad-spectrum antibacterial activity.

Bacterial infection accompanied by antibiotic resistance leads to the lack of effective antibacterial agents, which has become an imminent problem afflicting people. Therefore, development of highly effective and broad-spectrum disinfecting alternatives to tackle this challenge is of great necessity. In view of the different cell wall structures of bacteria, we designed photodynamic antibacterial system based on chlorin e6 (Ce6) loaded chitosan functionalized molybdenum sulfide (MoS2) nanocomposites (M-CS-Ce6). The nanocomposite can not only allow Ce6 to enter the cells of Gram-positive bacteria, but also destroy the cell wall permeability of Gram-negative bacteria and enhance the photo-antibacterial effect. 10 µg/mL of M-CS-Ce6 irradiated by 660 nm laser for 5 min, completely killed the target pathogens, exhibiting significantly enhanced photo-antibacterial performance against both Gram-positive and Gram-negative bacteria. Compared with other cationic photodynamic composites, M-CS-Ce6 had stronger and broad-spectrum photo-antibacterial effect. Taken together, M-CS-Ce6 could be a promising and safe broad-spectrum antibacterial agent.

Effect of rutin on the physicochemical and gel characteristics of myofibrillar protein under oxidative stress.

The effects of rutin (6, 30, and 150 µmol/gpro ) on the physicochemical, structural properties and gel characteristics of myofibrillar protein (MP) under oxidative stress were investigated. The addition of rutin significantly promoted the formation of oxidized MP carbonyl derivatives and dimer tyrosine, but it cannot prevent the loss of sulfhydryl groups (-SH). With increasing rutin concentration, the hydrophobic area was gradually shielded and rutin acted as a quencher to reduce the fluorescence intensity of oxidized MP. Under the oxidative stress, rutin increased the particle size and aggravated the cleavage of protein molecules. SDS-polyacrylamide gel electrophoresis revealed that rutin further aggravated oxidized MP degradation and cross-linked form polymer which cross-linked with protein to the maximum extent at 150 µmol/gpro rutin content. Moderate cross-linking between protein and rutin could improve the gel strength and water holding capacity (WHC) of oxidized MP gel. For rutin concentrations of 6 and 30 µmol/gpro , the gels had denser network structures, as observed by scanning electron microscopy. PRACTICAL APPLICATIONS: Polyphenols of the type and dosage can change the properties of the product itself and optimize the quality of product processing. Certain polyphenols may promote the oxidation process of protein-rich products, but this does not affect the improvement of product quality. The application of natural polyphenols is the promising business direction in the development of Coregonus peled industry.

Real-time monitoring of active caspase 3 during AFB1 induced apoptosis based on SERS-fluorescent dual mode signals.

Aflatoxin B1 (AFB1) is the most toxic mycotoxin. Usually, the toxin activated apoptosis is considered mostly through intrinsic mitochondrial pathway while the caspase family as promoter and executor plays a crucial role. In this paper, a real-time and in situ detection of caspase 3 in living cells based on SERS-fluorescence dual mode nanosensor was studied. Firstly, gold nanotriangles (AuNTs) modified with the caspase 3 specifically recognized polypeptide chain DEVD were synthesized as both SERS enhanced substrate and fluorescent quencher. Rhodamine B (Rb) as both Raman and fluorescent signal molecules was modified on the N end of DEVD chain. After active caspase 3 specifically cut off the recognition site in DEVD, partial peptide chain with Rb fell off from the surface of AuNTs. Thus, the Raman signal of Rb decreased while its fluorescent signal recovered. There was a good linear relationship between caspase 3 and both the SERS and fluorescence signals of Rb. The minimum detection limit was 0.001 nM. After cells were stimulated by AFB1, when Cyt C in the cytoplasm reached a certain level, caspase 3 was activated. This nanosensor was realized in certain living cells (HepG2, HeLa and A549). Based on monitoring the activation of specific apoptotic markers, the conduction of marker signals in real time can provide more detailed information for apoptosis.

A phosphorescence resonance energy transfer-based "off-on" long afterglow aptasensor for cadmium detection in food samples.

Cadmium contamination is a severe food safety risk for human health. Herein, a long afterglow "off-on" phosphorescent aptasensor was developed based on phosphorescence resonance energy transfer (PRET) for the detection of Cd2+ in complex samples which minimizes the interference of background fluorescence. In this scheme, initially the phosphorescence of Cd2+-binding aptamer conjugated long afterglow nanoparticles (Zn2GeO4:Mn) was quenched by black hole quencher 1 (BHQ1) modified complementary DNA. Upon encountering of Cd2+, the aptamer interacted with Cd2+ and the complementary DNA with BHQ1 was released, leading to phosphorescence recovery. The content of Cd2+ could be quantified by the intensity of phosphorescence recovery with 100 µs gate time (which eliminated the sample autofluorescence) with a linear relationship between 0.5 and 50 µg L-1 and a limit of detection (LOD) of 0.35 µg L-1. This method was successfully demonstrated for Cd2+ detection in drinking water and yesso scallop samples. The "off-on" phosphorescent aptasensor based on PRET of long afterglow nanomaterials could be an effective tool for Cd2+ detection in food samples.