Polymeric Nanohybrids Engineered by Chitosan Nanoparticles and Antimicrobial Peptides as Novel Antimicrobials in Food Biopreservatives: Risk Assessment and Anti-Foodborne Pathogen Escherichia coli O157:H7 Infection by Immune Regulation.

Polymeric nanomaterials (APs) are gaining attention as promising clinical antimicrobials with rapidly increasing antibiotic resistance. Infections by zoonotic enterohemorrhagic Escherichia coli are a severe global threat to public health. Chitosan nanoparticles-microcin J25 (CNM), a class of APs engineered by bioactive peptides and chitosan nanoparticles, can be used as a novel antimicrobial agent against bacterial infections. However, the risk assessment of CNM on animal health or its potential immune modulation to treat serotype E. coli O157:H7 infection impacts in vivo are not well understood. Herein, our findings in mouse models uncovered that oral administration of low levels of CNM significantly increased the body weight and made beneficial effects on the lifespan or clinical signs, accompanied by a significant improvement in gut health, including enhancing the intestinal barrier, immune modulation, and changes in gut microbiota compositions or metabolites. However, high concentrations of CNM induced serious adverse effects, negatively improving intestinal health targets. Anti-infective results proved that oral 0.1% CNM enhances host defense against E. coli O157:H7 infection by improving immune functions and modulating the Th1/Th2 balance. In summary, these findings uncover an instrumental link between the dosage and toxicity risk, suggesting that APs need to be comprehensively assessed for risk before application as safe and reliable food preservatives or therapeutic agents. In addition, CNM as a promising AP may markedly enhance host immunity and therapeutic effects by oral administration.

Determination of trace alkaline phosphatase by affinity adsorption solid substrate room temperature phosphorimetry based on wheat germ agglutinin labeled with 8-quinolineboronic acid phosphorescent molecular switch and prediction of diseases.

The 8-quinolineboronic acid phosphorescent molecular switch (abbreviated as PMS-8-QBA. Thereinto, 8-QBA is 8-quinolineboronic acid, and PMS is phosphorescent molecular switch) was found for the first time. PMS-8-QBA, which was in the "off" state, could only emit weak room temperature phosphorescence (RTP) on the acetyl cellulose membrane (ACM). However, PMS-8-QBA turned "on" automatically for its changed structure, causing that the RTP of 8-QBA in the system increased, after PMS-8-QBA-WGA (WGA is wheat germ agglutinin) was formed by reaction between -OH of PMS-8-QBA and -COOH of WGA. More interesting is that the -NH(2) of PMS-8-QBA-WGA could react with the -COOH of alkaline phosphatase (AP) to form the affinity adsorption (AA) product WGA-AP-WGA-8-QBA-PMS (containing -NH-CO- bond), which caused RTP of the system to greatly increase. Thus, affinity adsorption solid substrate room temperature phosphorimetry using PMS-8-QBA as labelling reagent (PMS-8-QBA-AA-SSRTP) for the determination of trace AP was established. The method had many advantages, such as high sensitivity (the detection limit (LD) was 2.5zgspot(-1). For sample volume of 0.40mulspot(-1), corresponding concentration was 6.2x10(-18)gml(-1)), good selectivity (the allowed concentration of coexisting material was higher, when the relative error was +/-5%), high accuracy (applied to detection of AP content in serum samples, the result was coincided with those obtained by enzyme-linked immunoassay), which was suitable for the detection of trace AP content in serum samples and the forecast of human diseases. Meanwhile, the mechanism of PMS-8-QBA-AASSRTP was discussed. The new field of analytical application and clinic diagnosis technique of molecule switch are exploited, based on the phosphorescence characteristic of PMS-8-QBA, the AA reaction between WGA and AP, as well as the relation between AP content and human diseases. The research results promote the development and interpenetrate among molecule switch technique, lectin science and SSRTP.

Determination of trace glucose and forecast of human diseases by affinity adsorption solid substrate-room temperature phosphorimetry based on triticum vulgaris lectin labeled with dendrimers-porphyrin dual luminescence molecule.

In this paper, 3.5-generation polyamidoamine dendrimers (3.5G-D)-porphyrin (P) dual luminescence molecule (3.5G-D-P) was developed as a new phosphorescence-labeling reagent. Meanwhile, the room temperature phosphorescence (RTP) characteristics of 3.5G-D-P and its product of labeling triticum vulgaris lectin (WGA) on the surface of polyamide membrane (PAM) were studied. Results showed that in the presence of heavy atom perturber LiAc, 3.5G-D and P of 3.5G-D-P molecule could emit strong and stable RTP on the PAM. And the Tween-80 would spike thoroughly the phosphorescence signal of 3.5G-D and P; moreover, specific affinity absorption (AA) reaction between the products (Tween-80-3.5G-D-P-WGA) of WGA labeled with Tween-80-3.5G-D-P and glucose (G) was carried out. The products of the AA reaction could keep good RTP characteristics of 3.5G-D and P dual luminescence molecule, and the DeltaI(p) was linear correlation to the content of G. According to the facts above, a new method of affinity adsorption solid substrate-room temperature phosphorimetry (AA-SS-RTP) for the determination of trace G was established, basing on WGA labeled with Tween-80-3.5G-D-P dual luminescence molecule. The detection limit of this method was 0.13fgspot(-1) (1.7x10(-12)moll(-1), 3.5G-D) and 0.14fgspot(-1) (2.2x10(-12)moll(-1), P). Determination of G in human serum using excitation/emission wavelength of either 3.5G-D or P, the result was coincided with enzyme-linked immunosorbent assay (ELISA). Not only the sensitivity and accuracy of this method were higher, but also the flexibility of AA-SS-RTP was obviously improved and the applicability was wider.

Determination of trace alpha-fetoprotein variant by affinity adsorption solid substrate-room temperature phosphorimetry and its application to the forecast of human diseases.

In the presence of ion perturber LiAc, 4-generation polyamidoamine dendrimers (4G-D) could emit strong and stable room temperature phosphorescence (RTP) signal at lambda(max)(ex)/lambda(max)(em) = 511.8/675.3 nm on nitrocellulose membrane (NCM), and Triton X-100 could sharply enhance the RTP signal of 4G-D. Triton X-100-4G-D was used to label concanavalin agglutinin (Con A) to get the labeling product Triton X-100-4G-D-Con A. Quantitative specific affinity adsorption (AA) reaction between Triton X-100-4G-D-Con A and alpha-fetoprotein variant (AFP-V) could be carried out on the surface of NCM, whose product Triton X-100-4G-D-Con A-AFP-V could emit strong and stable RTP and its deltaI(p) was proportional to the content of AFP-V. According to the facts above, a new affinity adsorption solid substrate-room temperature phosphorimetry (AA-SS-RTP) for the determination of trace AFP-V by Con A labeled with Triton X-100-4G-D was established. Detection limits of this method were 0.23 fg spot(-1) (direct method, corresponding concentration: 5.8x10(-13) g mL(-1)) and 0.13 fg spot(-1) (sandwich method, corresponding concentration: 3.2x10(-13) g mL(-1)). It has been successfully applied to determine the content of AFP-V in human serum and forecast human diseases, for its high sensitivity, long RTP lifetime, good repeatability, high accuracy and little background perturbation with lambda(max)(em) at the long wavelength area. Meanwhile, the mechanism for the determination of trace AFP-V using AA-SS-RTP was also discussed.