Silver nanoparticles
(Ag NPs) are widely used against bacteria,
but further applications are restricted by their cytotoxicity. Their
antibacterial efficiency cannot be measured because of the risk of
development of multidrug resistance (MDR) with use of antibiotics.
An alloy nanostructure of gold nanoparticles (Au NPs) inlaid on Ag
NPs was synthesized using egg white protein (denoted here as Au–Ag
NPs), exhibiting an enhanced antibacterial effect and can visually
indicate the antibacterial efficacy by fluorescence. Interestingly,
the fluorescence recovered after antibacterial action. Au–Ag
NPs showed enhanced antibacterial effect, due to higher reactive oxygen
species (ROS) generation than Ag NPs, after adhering to the surface
of bacteria, suggesting that the silver content in Au–Ag NPs
can be tuned to reach high antibacterial activity with low cytotoxicity.
Au–Ag NPs visualized bacteria by fluorescence changes, which
makes the antibacterial process clear and allows the dosage of antibacterial
agents to be controlled accurately, which can prevent MDR. Efficient
antibacterial activity coupled with the ability to visualize bacterial
processes allow Au–Ag NPs to be a potential solution in medicine
and biosensing.
Wound infection caused by multiantibiotic-resistant bacteria has become a serious problem, and more effective antibacterial agents are required. Herein, we report the preparation of wound dressings using the biocompatible chitosan (CS) as a reducing and stabilizing agent in the synthesis of 2-mercapto-1-methylimidazole (MMT)-capped gold nanocomposites (CS-Au@MMT), with efficient antibacterial effects. The synergistic effects of AuNPs, MMT, and CS led to the disruption of bacterial membranes. After blending with gelatin, crosslinking with tannin acid, and freeze-drying, CS-gelatin (CS-Au@MMT/gelatin) dressing was prepared. It had good mechanical properties as well as efficient water absorption and retention capacities. It exhibited outstanding biocompatibility both in vitro and in a cell-based wound infection model. Moreover, the in vivo rabbit wound healing model revealed that the CS-Au@MMT/gelatin dressing possesses significant antibacterial potential against methicillin-resistant Staphylococcus aureus-associated wound infection. Therefore, the CS-Au@MMT/gelatin dressing described in this study may have huge potential in biomedical applications.
Immediate
hemorrhage control is pivotal for saving lives both in
civilian life and in the military. In the present study, we developed
a three-dimensional carrier based on the enzymolysis of corn starch
loaded with thrombin, which efficiently controlled bleeding in a short
time. The microporous starch (MS) with a large surface area was modified
with sodium trimetaphosphate (STMP) to generate starch phosphate,
which showed enhanced thrombin entrapment efficiency. The thrombin-assembled
MS-STMP structure (MS-STMP-T) showed excellent hydrophilicity, rapid
water absorption, high negative surface charge, and high hemostatic
efficiency upon contact with blood in whole blood clotting tests,
APTT and PT measurements, and animal injury models. Additionally,
MS-STMP-T showed no cytotoxicity and was degraded within 14 days in
a rabbit model. These results indicate that MS-STMP-T is a safe and
effective agent for the control of bleeding.
Tetrodotoxin (TTX) was simultaneously detected in the fresh and heat-processed aquatic products by high-performance liquid chromatography–tandem mass spectrometry method. The detection conditions were investigated, including the chromatography column and mobile phase. Based on the optimized parameters, a sensitive determination method of TTX was established. The proposed method featured the merits of a good linear relationship between signal and TTX concentration (R2 = 0.9998), a wide detection matrix-based range of 0.2–100 ng/g, and a low detection limit of 0.2 ng/g, etc. The spiked assays evidenced its accuracy and reliability with recoveries of 90.5–107.2%. Finally, the developed method was simultaneously successfully applied in the determination of TTX in various fresh and heat-processed aquatic products.
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