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Infection with gram-negative bacteria is the main source of the most serious infectious pathogens. Developing new antibacterial materials that break through their external membranes and stay in the bacterial body to result in an antibacterial effect is the key to achieving high efficiency against Gram-negative bacteria. A Gd-doped carbon dot (GRCD) was prepared using the approved therapeutic diagnostic agents Rose Bengal (RB) and gadolinium ions (Gd 3+ ), which was used to resist Gram-negative bacteria (e.g. E. coli, Escherichia coli). GRCD not only showed strong antibacterial activity by destroying the external membranes of E. coli (inhibition rate against E. coli was 92.0 % at 20 μg/mL) but also bound to E. coli DNA and generated single oxygen ( 1 O 2 ) (quantum yield was 0.50) through visible light-driven catalysis, thus decomposing the DNA of E. coli and further enhancing the antibacterial performance of GRCD. Under visible light conditions, the inhibition rate against E. coli reached 95.8 % at a low concentration of 2.5 μg/mL, without obvious cytotoxicity to NIH3T3 cells. The use of GRCD in treating wound infections in mice caused by E. coli was quite good, without side reactions on the mice's essential organs. In this study, a new approach has been provided to the design and synthesis of carbon dot nanocomposites for use against Gram-negative bacteria., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Regulation of photosynthesis rates is one of the key ways to increase crop yields. Carbon dots (CDs), which are low-toxity and biocompatible optical nanomaterials, can be easily prepared and are ideal for improving photosynthesis efficiency. In this study, nitrogen-doped CDs (CNDs) with a fluorescent quantum yield of 0.36 were synthesized via a one-step hydrothermal method. These CNDs can convert a part of ultraviolet light in solar energy to blue light (emission peak at 410 nm) that can be utilized in photosynthesis and that overlaps with the optical absorption spectrum of chloroplasts in the blue light zone. Consequently, chloroplasts can pick up photons excited by the CNDs and transfer them to the photosynthetic system in the form of electrons, thereby accelerating the photoelectron transport rate. These behaviors can reduce ultraviolet light stress on wheat seedlings and improve the efficiency of electron capture and transfer from chloroplasts through optical energy conversion. As a result, various photosynthetic indices and biomass of wheat seedlings are improved. Cytotoxicity experiments have showed that CNDs within a certain concentration range almost do not affect cell survival., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

By taking TC base-rich single-stranded DNA (ssDNA) as the raw material, a fluorescent biological quantum dots (Bio-dots) probe was prepared in one step through hydrothermal method, where its lifetime was greatly extended in comparison with Carbon quantum dots (CQDs), reaching 10.7 ns. The fluorescent detection of melamine in milk samples was realized by using the base pairing principle. Under the optimal conditions, the linear range of Bio-dots probe fluorescence sensor for melamine detection is 5-600 μM, and the detection limit is (3σ) 1.4 μM. Bio-dots can not only emit photoluminescence, but also detect target molecules as a functional recognition group. As the raw material ssDNA was basically non-toxic and there was no toxic substances participated in its synmanuscript process, this Bio-dots probe was a kind of green and environmentally-friendly photoluminescent functional material., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Environmental friendly nano biosensor can improve the detection performance of traditional biomolecular sensors and have important application value in practical applications. In this study, a kind of room temperature phosphorescence (RTP) quantum dots (QDs) (GOX RTP QDs) nanobiosensor was prepared by mineralization at room temperature (25 °C), using galactose oxidase (GOX) as template, which improved the catalytic ability of traditional GOx to D-Galactose. The specific enzyme substrate reaction between GOx and D-Galactose and photoinduced electron transfer (Piet) were used to detect the RTP of D-galactose. The linear range of D-galactose detection is 0.02-0.8 mM, and the detection limit of the method is 0.008 mM. This method is based on the RTP property of QDs, which can effectively avoid the interference of background fluorescence of biological samples, and does not need complex sample pretreatment process. Therefore, this method is more suitable for the quantitative detection of D-Galactose in biological samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this study, green low-toxicity Mn-doped Zns (Mn-Zns) room-temperature phosphorescent (RTP) quantum dots (QDs) (PQDs) nanocomposites (DNA-PQDs) were prepared under the optimal conditions by using single-stranded DNA (PS-C-ssDNA) rich of cytosine C and Thioguanine G (PS) as the template. DNA-PQDs interact with Ag + to form AgN bonds and further produce C-Ag + -C conjugates. As a result, DNA-PQDs cluster together and induce the phosphorescent exciton energy transfer (PEET), resulting in quenching of room-temperature phosphorescent of DNA-PQDs. Nevertheless, Ag + tends to form AgS bonds with biological mercaptan when it is added in, so that Ag + falls from C-Ag + -C. DNA-PQDs changed from aggregation to looseness and RTP is recovered accordingly. On this basis, RTP detection of biological mercaptan is realized. Since this sensor system has RTP properties based on DNA-PQDs, it is very applicable to detection of mercaptan compounds in biological fluids., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A simple and rapid liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and used to determine eight antipsychotics (aripiprazole, clozapine, haloperidol, olanzapine, paliperidone, quetiapine, risperidone, and ziprasidone) in human serum for practical clinical usage. Stable isotope-labeled internal standards were used for all drugs to compensate for method variability, including matrix effects, ion extraction and ionization variations. Samples were prepared by simple protein precipitation with methanol. Chromatographic separation was accomplished in less than 3.3 min on a KINTEX C18 column (50 mm × 3.0 mm, 5 μm) using a gradient elution of 2 mM aqueous ammonium formate and methanol at a flow rate of 0.5 mL/min. Quantification was performed by multiple reaction monitoring (MRM) in the positive mode. The method was fully validated according to the latest recommendations of international guidelines. The correlation coefficients of calibration curves were all greater than 0.9945. Internal standard-normalized matrix effects ranged from 96.3% to 115%, and extraction recoveries were between 88.1% and 107%. Coefficients of variation ranged from 1.82 - 13.5% for intra-day precision, 5.69-14.7% for inter-day precision, and the relative error for accuracy did not exceed ± 13.5% for any analyte. The method was successfully applied to routine clinical therapeutic drug monitoring for 2,173 samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A simple phosphorescence method is proposed for quercetin detection based on Al(3+)-amplified room-temperature phosphorescence (RTP) signals of 3-mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs). The sensor was established based on some properties as follows. Al(3+) can interact with carboxyl groups on the surface of MPA-capped Mn-doped ZnS QDs via chelation, which will lead to the aggregation of QDs and amplification of RTP signals, After the addition of quercetin, it can form more stable complex with Al(3+) in alkaline aqueous solution and dissociate Al(3+) from the surface of Mn-doped ZnS QDs, which will result in significant recovery of RTP intensity of the MPA-capped Mn-doped ZnS-Al(3+) system. Under the optimized conditions, the change of RTP intensity was proportional to the concentration of quercetin in the range from 0.1 to 6.0 mg L(-1), with a high correlation coefficient of 0.996 and a detection limit of 0.047 mg L(-1). The proposed method is potentially suitable for detection of quercetin in real samples without complicated pretreatment., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Quantum dot (QD) nanohybrids provide an effective route to explore the new properties of materials and are increasingly used as highly valuable sensitive (bio) chemical probes. Interestingly, the room-temperature phosphorescence (RTP) of 3-mercaptopropionic acid (MPA)-capped Mn-doped ZnS QDs could be remarkably enhanced by the addition of protamine. Based on the above finding, a simple, sensitive, and selective method for rapid detection of protamine was successfully designed. With this method, protamine as a cationic peptide interacts electrostatically with MPA-capped Mn-doped ZnS QDs to form MPA-capped Mn-doped ZnS QD/protamine complexes, which leads to the aggregation of QDs and enhances the RTP intensity. Under the optimized conditions, the RTP intensity change was linearly proportional to the concentration of protamine in the range 0.2-3.0 μg ml(-1), and the limit of detection was 0.14 μg ml(-1). The proposed method was successfully applied to detect protamine in protamine sulfate injection and human serum samples with satisfactory results, and the recovery ranged from 96.5 to 105.6%., (Copyright © 2015 Elsevier Inc. All rights reserved.)

A "turn off-on" switch mode was established by using the interaction between acridine orange (AO) and DNA as an input signal and using the room temperature phosphorescence (RTP) reversible change of 3-mercaptopropionic acid (MPA)-capped Mn-doped ZnS quantum dots (QDs) as an output signal in biological fluids. AO was absorbed into the surface of Mn-doped ZnS QDs via electrostatic attraction and, thus, formed a ground-state complex through photoinduced electron transfer (PIET). This complex quenched the phosphorescence of Mn-doped ZnS QDs and then rendered the system into the "turn-off" mode. Along with the addition of DNA and embedded binding with DNA, AO was competitively induced to fall off from the surface of Mn-doped ZnS QDs and embed into the double helix structure of DNA. As a result, the RTP of Mn-doped ZnS QDs was recovered and the system consequently was rendered into "turn-on" mode. In this case, a new biosensor for DNA detection was built and has a detection limit of 0.033mgL(-1) and a detection range from 0.033 to 20mgL(-1). What is more, this kind of biosensor does not require complex pretreatments and is free from the interference from autofluorescence and scattering light. Thus, this biosensor can be used to detect DNA in biological fluids., (Copyright © 2015 Elsevier Inc. All rights reserved.)