Tyrosine-modified tilapia skin antioxidant peptides and their hydroxyl radical quenching activities.

In an antioxidant peptide study, the number and position of active amino acid sites, as well as the peptides' conformation, are found to be crucial for scavenging hydroxyl radicals (˙OH). Herein, ˙the OH scavenging activity of tilapia pentapeptide (P1, YGDQY) and its analogs including P2 (YYYGDQY), P3 (YYGDQYY) and P4 (YYGPDQYY) was investigated. The results showed that the tyrosine's amount, location and the peptides' conformation played important roles in determining peptides' scavenging activity (34.

Rational design and construction of a mesoporous silica-supported ratiometric fluorescent probe for the sensitive detection of nicosulfuron.

The excessive use of pesticides is an urgent issue facing environmental sustainability and human health. In this study, a uniform dispersion size, good fluorescence performance and mesoporous structure of a ratiometric fluorescent probe were constructed for nicosulfuron detection. A solvent-free in situ solid-phase synthesis method was used to encapsulate biomass carbon dots within mesoporous silica (CDs@mSiO₂), followed by the modification of l-cysteine-modified manganese-doped zinc sulfide quantum dots (ZnS:Mn QDs), to construct a ratiometric fluorescent probe for highly sensitive and selective detection of nicosulfuron.

Zearalenone degradation by peptide-based enzyme mimics attached membrane reactor: Performance and mechanism.

Zearalenone (ZEN) is a nonsteroidal estrogenic mycotoxin with widespread contamination. Inspired by lactone hydrolases, a peptide-based enzyme mimetic material for degrading ZEN was developed by combining serine, histidine and glutamate (S/H/E) catalytic triad with pro-hydrophobic self-assembling sequences and oxyanion hole site. Chitosan hybrid membranes were prepared, followed by immobilizing enzyme mimic on the membrane surface to fabricate biocatalytic membrane reactor.

Degradation and detection of organophosphorus pesticides based on peptides and MXene-peptide composite materials.

Safety problems caused by organophosphorus pesticide (OP) residues are constantly occurring, so the development of new methods for the degradation and detection of OPs is of great scientific significance. In the present study, β-sheet peptides and β-hairpin peptides for catalyzing the hydrolysis of OPs were designed and synthesized. The peptide sequences with the highest hydrolytic activity (EHSGGVTVPPLTVEHSAG) were screened by investigating the effect of the location of the active sites of the peptide and the peptide's structure on the degradation of OPs.

Degradation of Di (2-ethylhexyl) phthalic acid plasticizer in baijiu by a foam titanium flow reactor attached with hairpin-like structured peptide enzyme mimics.

Because of the significant environmental and health hazards imposed by di(2-ethylhexyl) phthalate (DEHP), a common plasticizer, developing safe and green techniques to degrade DEHP plasticizer is of huge scientific significance. It has been observed that environmental contamination of DEHP may also induce serious food safety problems because crops raised in plasticizers contaminated soils would transfer the plasticizer into foods, such as Baijiu. Additionally, when plastic packaging or vessels are used during Baijiu fermentation and processing, plasticizer compounds frequently migrate and contaminate the product.

Smartphone-integrated dual-emission fluorescence sensing platform based on carbon dots and aluminum ions-triggered aggregation-induced emission of copper nanoclusters for on-site visual detecting sulfur ions.

A ratiometric fluorescence strategy was proposed based on carbon dots (CDs) and self-assembled copper nanoclusters (CuNCs) driven by Al ions for S detection. Si-CDs/CuNCs@Al exhibits blue and red emission under single excitation. Interestingly, the red emission of the CuNCs was regularly quenched while the blue fluorescence emission of the CDs was preserved after continuous addition of S.

Fabrication of carbon dots@restricted access molecularly imprinted polymers for selective detection of metronidazole in serum.

A custom-tailored design was proposed for the fabrication of carbon dots coupled with restricted access materials and molecularly imprinted polymers (CDs@RAM-MIPs) to detect metronidazole (MNZ). Biomass carbon dots (CDs) were derived from longan peels assisted with high pressure microwave, and had the merits of eco-friendly, excellent photostability and low toxicity. In this work, glycidyl methacrylate was used as a co-polymeric monomer to increase hydroxyl groups on the surface of synthetic materials, which eliminated the interference of biological macromolecules.

Microwave-assisted facile synthesis of polymer dots as a fluorescent probe for detection of cobalt(II) and manganese(II).

Polymer dots (PDs) were synthesized at 200 °C for 90 min via a microwave-assisted method. The PDs were characterized by fluorescence spectroscopy, UV-vis absorbance spectra, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The PDs display blue fluorescence under 320 nm excitation with a fluorescent quantum yield of 13.

Molecularly imprinted polymers combined with membrane-protected solid-phase extraction to detect triazines in tea samples.

Spherical molecularly imprinted polymers (MIPs) were prepared by emulsion polymerization. The isothermal adsorption and selective adsorption indicated that the MIPs obtained exhibit excellent specific recognition for the template (atrazine) and its analogues. The MIPs were encapsulated in a polypropylene microporous membrane to fabricate MIP adsorption packages for the direct extraction of triazines in uncentrifuged and unfiltered tea extracts.

Microwave-assisted preparation of boron acid modified expanded graphite for the determination of chloramphenicol in egg samples.

A rapid and simple method for the synthesis of boron acid modified expanded graphite (B-EG) with the assist of microwave irradiation was developed. The synthesis process can be completed in one-step, where HSO and HBO were used as intercalating agent and KMnO was used as oxidizing agent. The obtained B-EG was worm-like and lamellar structure with plenty of small dispersed particles.

Single-hole hollow molecularly imprinted polymer embedded carbon dot for fast detection of tetracycline in honey.

It is difficult to detect tetracycline (TC) in honey sample by using carbon dots (CDs) because the autofluorescence of the matrix of honey sample overlaps with the fluorescence emission spectrum of the large majority of CDs. Herein, single-hole hollow molecularly imprinted polymers embedded carbon dots (HMIP@CD) was prepared via microwave-assisted method. TC in diluted honey sample was adsorbed by the HMIP@CD within 3 min, after which the HMIP@CD absorbed with TC was separated by centrifugation from honey sample and redispersed into phosphate buffer solution.

Selective detection of copper ion in complex real samples based on nitrogen-doped carbon quantum dots.

Highly selective nitrogen-doped carbon quantum dots (ND-CQDs) for copper ion (Cu) determination were synthesized by a solvent-free pyrolysis of citric acid and histidine. The resultant ND-CQDs display a stable bright blue fluorescence with a satisfactory product yield of 56% and quantum yield of 16%. The ND-CQDs not only show good photostability under continuous UV irradiation, but are also dramatically stable against extreme ionic strengths.

Microwave-assisted synthesis of carbon dots for "turn-on" fluorometric determination of Hg(II) via aggregation-induced emission.

A fluorescent probe is presented for sensitive determination of Hg(II). It is based on aggregation induced enhancement effect (AIEE) of carbon dots co-doped with nitrogen and sulfur (N,S-CDs). The N,S-CDs were prepared by a one-pot microwave-assisted method using glycerol as the reaction solvent, and cystine as the source for C, N and S.