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A novel strategy for cytochrome c selective recognition assisted with cucurbit[6]uril by host-guest interaction via N-terminal epitope imprinting and reversible addition-fragmentation chain transfer (RAFT) polymerization was developed. N-terminal nonapeptide of cytochrome c (GI-9) was used as the epitope template to achieve highly selective recognition of cytochrome c. As a common supramolecule in recent years, cucurbit[6]uril can encapsulate the butyrammonium group of lysine residue to capture the peptide and improve the corresponding spatial orientation by the host-guest interaction for GI-9 or cytochrome c recognition. After cucurbit[6]uril modification and epitope immobilization, the imprinted polymer was synthesized by RAFT polymerization with 2-dodecylsulfanylcarbothioylsulfanyl-2-methylpropanoic acid as chain transfer agent. After template removal, the obtained imprinted particles showed good binding ability to GI-9 (20.28 mg g^-1, IF = 4.11) and cytochrome c (36.12 mg g^-1, IF = 3.91). With the successive addition of cucurbit[6]uril and RAFT agent, the step-by-step improvement of the IF for cytochrome c recognition further illustrated the effects of supramolecular host-guest interaction and regulation of imprinted polymer chain. The imprinted polymers showed obvious advantages for cytochrome c recognition compared to competitive proteins and had good reusability with the repeated reproduction rate 80.8 % after five cycles of adsorption and desorption. Furthermore, the selective recognition for cytochrome c in adult bovine serum proved its potentiality to be applied in practical samples. All these results demonstrated that the combination of epitope imprinting, cucurbit[6]uril host-guest interaction and RAFT strategy presented an efficient new feasible control method for protein recognition with good selectivity, stability and reusability.

Formaldehyde (HCHO) is a harmful volatile organic pollutant, which is commonly found in interior decoration and furniture products. Therefore, it is necessary to develop a gas sensor that can quickly and accurately detect formaldehyde for human health and environmental protection. In order to achieve this goal, in this work, SnS₂/SnO₂ heterostructure was synthesized by in-situ sulfurization process on the basis of SnO₂ nanospheres, and its formaldehyde sensing performance was studied. After testing, it was found that the gas sensor based on SnS₂/SnO₂ heterojunction has more excellent gas sensing performance than pure SnO₂ gas sensor at the same operating temperature (100 °C). Specifically, SnS₂/SnO₂-2 (Sn:S = 3:2) has the advantages of high sensitivity (4.01 at 0.1 ppm), excellent selectivity, low theoretical detection limit (13.26 ppb), good humidity resistance and long-term stability. The excellent sensing performance of SnS₂/SnO₂ sensors for formaldehyde detection is mainly attributed to the n-n heterojunction formed by SnS₂ and SnO₂, which generates a built-in electric field to accelerate the electron transport in the material, the higher oxygen vacancy sites adsorb a large number of reactive gas molecules to promote the oxidation of formaldehyde molecules, and the unique porous structure to promote the transmission and diffusion of gases and increase the surface area to provide more adsorption sites and reactive centers for gas molecules. Therefore, the construction of SnS₂/SnO₂ heterostructures will be an effective way to develop next-generation formaldehyde gas sensors with higher sensing performance.

Glucose detection is crucial for diagnosis, prevention and treatment of diabetes mellitus. In this work, 10 nm Al₂O₃ thin film was introduced on the channel of diamond solution-gate field-effect transistor (SGFET) to improve the performance of glucose detection. AFM results show the roughness of channel surface increased after Al₂O₃ thin film deposition. Then, 1-pyrenebutyric acid-N-hydroxy succinimide ester (Pyr-NHS) and glucose oxidase (GOD) were linked on the channel. The morphology after each modification step was evaluated by SEM, and the result indicated an uneven Al₂O₃ distribution. XPS spectra further confirmed the effective modification of Pyr-NHS and GOD. In addition, the shifts of transfer characteristics for each concentration of glucose were analyzed, which illustrated a wide linear response (10^-8-10^-2 M), a high sensitivity (-44.01 mV/log₁₀[glucose concentration]) and a low detection limitation (10^-8 M). All these results show an excellent detection performance, which may provide a new idea for the design of diamond SGFET biosensor.

Searching for new alternative to tripropylamine (TPrA) with low toxicity and high chemical stability for the tris(4,4'-dicarboxylic acid-2,2'-bipyridyl)ruthenium (II) (Ru(dcbpy)₃²⁺) based coreactant electrochemiluminescence (ECL) system is essential for widespread analytical applications. Here, nitrogen-doped graphene quantum dots (NGQDs) have been discovered to significantly amplify the ECL emission and increase the ECL efficiency of Ru(dcbpy)₃²⁺ for the first time. However, the mechanism by which NGQDs act as coreactants is not well comprehended. Therefore, various optical and electrochemical technologies were employed to investigate the ECL mechanism. It is proposed that the amino and carboxyl groups on the surface of NGQDs play crucial roles as the coreactant active sites, catalyzing the oxidation of Ru(dcbpy)₃²⁺. Based on this foundation, an "on-off-on" ECL aptasensor for the quantification of acetamiprid was developed, exhibiting a broad linear range and a detection limit of 0.056 pM. Satisfactory recoveries, ranging from 98.0 % to 101.6 %, were achieved in pakchoi samples. Consequently, NGQDs could serve as coreactants for Ru(dcbpy)₃²⁺, offering new opportunities for constructing a variety of sensors with extensive analytical applications in the ECL field.

Polymers and dendrimers are macromolecules, possessing unique and intriguing characteristics, that are widely applied in self-assembled functional materials, green catalysis, drug delivery and sensing devices. Traditional approaches for the structural characterization of polymers and dendrimers involve DLS, GPC, NMR, IR and TG, which provide their physiochemical features and ensemble information, whereas their unimolecular conformation and dispersion also are key features allowing to understand their transporting profile in confined ionic nanochannels. This work demonstrates the nanopore approach for the determination of charged homopolymers, neutral block copolymer and dendrimers under distinct bias potentials and pH conditions. The nanopore translocation properties reveal that the dispersion and transporting of PEI is pH-dependent, and its capture rate is much lower than that of PAA. The neutral block copolymer with longest molecular chain threads through with longest blockage duration, its highest capture rate was achieved in 0.5 M KCl at pH 5 with slow diffusion and high temporal resolution. The two generations of neutral dendrimers could also translocate under bias potentials, probably due to the ions adsorption on the dendrimers and driven by Brownian force. The TEG-81 with larger molecular size translocates with longer residence time and higher blockage ratio, as expected. Both of the dendrimers exhibit a higher blockage ratio at pH 7.4 than either acidic or alkalic condition, indicating a larger stretched conformation adopted under neutral condition. This work presents the analysis of unimolecular charged and neutral polymers and dendrimers, which will be insightful in understanding the self-assembly motion and transfer of synthetic macromolecules in confined space. It also provides a good indication for deciphering the macromolecule-nanopore interplay under electrophoretic condition.

Hypochlorous acid (HClO/ClO^-) is a common ROS that exhibits elevated activity levels in cancer cells. In this study, an ClO^--triggered TADF probe, PTZ-MNI, was designed based on a naphthalimide core. PTZ-MNI self-assemble in aqueous environments, exhibiting significantly enhanced fluorescence that demonstrated typical aggregation-induced delayed fluorescence (AIDF) characteristics. The probe not only showed high sensitivity to ClO^- but also exhibited remarkable selectivity over other reactive oxygen species and disturbance. PTZ-MNI displayed TADF characteristic, including sensitivity to oxygen in toluene, insensitivity to oxygen in aggregated states that maintain long fluorescence lifetimes, a vertical conformation, and a minimal ΔE_ST of 0.01 eV. Cell imaging studies showed the probe could trace ClO^- by red to green fluorescence in HeLa cell. The colocalization analysis indicated its excellent lysosome-targeting specificity. In addition, PTZ-MNI-O, the compound after oxidation, exhibited effective ROS generation ability and significant PDT effect after irradiation. This work provides guidance for the rational design of responsive TADF luminescent materials used in cell imaging and activatable-PDT.

Spatial metabolomics offers the combination of molecular identification and localization. As a tool for spatial metabolomics, mass spectrometry imaging (MSI) can provide detailed information on localization. However, molecular annotation with MSI is challenging due to the lack of separation prior to mass spectrometric analysis. Contrarily, surface sampling capillary electrophoresis mass spectrometry (SS-CE-MS) provides detailed molecular information, although the size of the sampling sites is modest. Here, we describe a platform for spatial metabolomics where MSI using pneumatically assisted nanospray desorption electrospray ionization (PA-nano-DESI) is combined with SS-CE-MS to gain both in-depth chemical information and spatial localization from thin tissue sections. We present the workflow, including the user-friendly setup and switching between the techniques, compare the obtained data, and demonstrate a quantitative approach when using the platform for spatial metabolomics of ischemic stroke.

Bacterial bloodstream infections cause high morbidity and mortality. Although bacteria can be detected by various methods, culture methods are often used for the detection of live, accurate, reproducible, and selective bacterial identification. However, the culture method is time-consuming, and clinicians often start treatment immediately due to the long determination time. This reduces the bacterial density detectable by culture, and in some cases, makes determination difficult. To overcome this challenge, we propose a method that directly combines bacteriophage-based lysis with quantitative PCR (qPCR). This method enables the simple and rapid detection of bacteria without the need for pre-concentration or DNA extraction steps. Escherichia coli K12 (E. coli K12) was used as the model bacterium, and bacteria lysed by the E. coli K12-specific bacteriophage were detected using qPCR. The total analysis time was less than 3 h, and only live bacterial cells were selectively lysed. The method was also used to detect bacteria spiked into reference plasma samples, and bacterial DNA was detected via qPCR. The results obtained from the calibration graph created with cultured bacteria and the one created by spiking bacteria into reference plasma were consistent. The similarities between the calibration graphs from both methods were found to be in the range of 92-102.7 %. The LOD and LOQ values for bacteria spiked into reference plasma were calculated as 14.80 and 3.5x10³ CFU/mL, respectively.

Near-infrared (NIR) spectroscopy analysis technology has become a widely utilized analytical tool in various fields due to its convenience and efficiency. However, with the promotion of instrument precision, the spectral dimension can now be expanded to include hundreds of dimensions. This expansion results in time-consuming modeling processes and a decrease in model performance. Hence, it is crucial to carefully choose representative features before constructing models. This paper focuses on the limitations of filter algorithms, which can only sort features and cannot directly determine the best subset of features. A hybrid method of combination of the Max-Relevance Min-Redundancy (mRMR) algorithm and the Genetic Algorithm (GA), as well as filter and wrapper feature selection methods, are combined to select appropriate features automatically. This hybrid algorithm retains the features in each individual that are considered to have a strong correlation and low redundancy by the mRMR algorithms during each iteration of the GA. On the other hand, it deletes the features that are regarded as having little correlation or high redundancy. Through the process of iteration, the feature subset is continuously optimized. We use the proposed hybrid method to select features on two datasets and establish various models to verify our proposed method in this paper. The experimental results indicate the feature selection approach, which combines mRMR with the GA, covers the advantages of both feature selection methods. This approach can select features that show good predictive performance. When compared with other common feature selection methods, such as the Uninformative Variable Elimination algorithm (UVE), Competitive Adaptive Reweighted Sampling algorithm (CARS), Successive Projections Algorithm (SPA), Iteratively Retains Informative Variables (IRIV), and GA, the hybrid algorithm can select a larger number of feature variables that are both representative and informative, additionally, it significantly enhances the predictive performance of the model.

Accurately detecting cysteine (Cys) in vivo is crucial for diagnosing Cys-related diseases. A novel ratiometric fluorescent probe featuring dual near-infrared emission is developed in this study for the in vivo ratio imaging of Cys. The probe comprises a hemicyanine organic small-molecule dye (HCy-CYS) with specific Cys recognition capabilities covalently coupled with carbon dots (CDs) synthesized using glutathione (GSH) as the carbon source (GCDs), forming a unique composite nanofluorescent probe (GCDs@CYS). The probe undergoes a specific reaction with acrylate upon the addition of Cys, converting HCy-CYS to HCy-OH. Consequently, the GCD fluorescence intensity at 685 nm gradually decreases, whereas that of HCy-OH at 720 nm progressively increases, yielding a ratiometric fluorescence signal. Notably, both emission wavelengths of the probe exceed 650 nm, thereby effectively mitigating the interference from background signals during cellular and in vivo imaging. Furthermore, the probe demonstrates high specificity for Cys, enabling its differentiation from homocysteine and GSH. The Cys concentration and fluorescence ratiometric intensity exhibit a strong linear correlation at 10-150 μM with a detection limit of 0.95 μM. These results indicate that the ratiometric fluorescent probe can serve as a valuable tool for monitoring Cys-related physiological or pathological processes.