Analytical Chemistry最新文献

Extracellular vesicles (EVs) offer promising noninvasive alternatives for convenient and noninvasive prostate cancer (PCa) diagnosis, but inefficient EV enrichment and cargo extraction hinder discovery and validation for their clinical applications. Here, we present an integrated pipeline based on functionalized magnetic beads to streamline and enhance the efficiency of urinary EV miRNA analysis. EVs are first enriched on amphiphilic magnetic beads through chemical affinity, followed by EV lysis and the isolation of miRNAs through solid phase extraction. The new pipeline demonstrated a more than 10-fold increase in urine EV miRNA extraction efficiency compared to the traditional ultracentrifugation combined TRIzol method while reducing the sample processing time to within 1 h. The one-bead strategy further allowed us to automate the procedure on a 96-channel instrument. We applied the pipeline to analyze urine samples from 108 benign prostatic hyperplasia (BPH) controls and 92 PCa cases. Among 195 miRNA biomarkers from the literature, we prioritized 18 miRNAs for quantification and successfully validated 12 miRNAs with a ratio-based normalized method. The quantification data from BPH controls and PCa cases in the training set were subjected to a machine learning analysis of Random Forest, through which we generated a five-miRNA panel consisting of miR-148a-5p, miR-21-5p, miR-181a-5p, miR-222-3p, and miR-100-5p. This panel showed high sensitivity (89%) and specificity (72%) in the test set, highlighting immense potential of this streamlined pipeline for noninvasive diagnosis.

The ability to uniquely identify a compound requires highly precise and orthogonal measurements. Here we describe a newly developed analytical platform that integrates high resolution ion mobility and cryogenic vibrational ion spectroscopy for high-precision structural characterizations. This platform allows for the temporal separation of isomeric/isobaric ions and provides a highly sensitive description of the ion's adopted geometry in the gas phase. The combination of these orthogonal structural measurements yields precise descriptors that can be used to resolve between and confidently identify highly similar ions. The unique benefits of our instrument, which integrates a structures for lossless ion manipulations ion mobility (SLIM IM) device with messenger tagging infrared spectroscopy, include the ability to perform high-resolution ion mobility separations and to record the IR spectra of all ions simultaneously. The SLIM IM device, with its 13 m separation path length, allows for multipass experiments to be performed for increased resolution as needed. It is integrated with an Agilent qTOF MS where the collision cell was replaced with a cryogenically held (30 K) TW-SLIM module. The cryo-SLIM is operated in a novel manner that allows ions to be streamed through the device and collisionally cooled to a temperature where they can form noncovalently bound N₂ complexes that are maintained as they exit the device and are detected by the TOF mass analyzer. The instrument can be operated in two modes: IMS+IR where the IR spectra for mobility-selected ions can be recorded and IR-only mode where the IR spectra for all mass-resolved ions can be recorded. In IR-only mode, IR spectra (400 cm^-1 spectral range) can be recorded in as short as 2 s for high throughput measurements. This work details the construction of the instrument and modes of operation. It provides initial benchmarking of CCS and IR measurements to demonstrate the utility of this instrument for targeted and untargeted approaches.

A major challenge for imaging-guided precise chemotherapy remains the ability to track the in situ real-time variation of the reactive oxygen species (ROS) level during treatment with prooxidation antitumor drugs. Chemiluminescence (CL) is widely used as an in vivo imaging tool with an excellent signal-to-noise ratio and high biological safety. However, suffering from flash-type and poor water solubility, most of the reported CL probes for ROS detection are unsuitable for in vivo long-term tracking. Herein, we designed a water-soluble CL nanohydrogel (L-012/Co²⁺@NGs) by cross-linking of vinyl-derived β-cyclodextrin monomer (MAH-β-CD) and loaded with luminol analog L-012 and cobalt ions (Co²⁺). In vitro studies reveal that L-012/Co²⁺@NGs exhibit long-lasting CL emission (up to 4 h) due to the slow diffusion of hydrogen peroxide in the nanohydrogel. High catalytic efficiency from the accelerated reduction of Co³⁺ to Co²⁺ through Tris and chelation of Co²⁺, as well as protection of the β-CD cavity against the active intermediate of L-012, enables L-012/Co²⁺@NGs to exhibit a 722-fold CL signal turn-on ratio and a nanomolar limit of detection (8.9 nmol/L). Piperlongumine (PL) was selected as a model of prooxidation drugs. The long-term and highly efficient CL strategy was designed for monitoring the local dynamic changes of ROS in PL-treated tumor-bearing mice for 150 min. The CL signal increased over time until reaching its maximum with a ∼6-fold increase at 15 min and then decreased slowly. The CL-functionalized nanohydrogel platform with good biocompatibility offers a great opportunity for imaging-guided precise tumor chemotherapy of PL and other prooxidation antitumor drugs.

We report a Technical Note on detecting nanoplastics in water samples through electrophoresis and quartz crystal microbalance (QCM) instrumentation. We conducted electrophoresis experiments by immersing a QCM in a sample of ultrapure water containing polyethylene (PE) nanoplastics. It was interesting to observe that nanoplastics were attracted toward the QCM and adhered to one side of the QCM electrode. The attached particles introduced mass loading to the QCM and were characterized by a decrease in resonance frequency of the crystal. Furthermore, when a small region around the center of electrode was alone exposed for direct contact in water and the rest of the electrode was masked using photoresist, the nanoplastics were concentrated only in the exposed electrode region, significantly enhancing detection sensitivity. To further investigate the applicability for real-life water samples, we experimented with the technique with readily available bottled drinking water and mineral water, where we spiked these water samples with nanoplastics. It was observed that the resonance frequency shifts were significantly larger for samples with nanoplastics compared to samples without nanoplastics. In addition, Raman spectroscopy and microscopy imaging were used to further confirm the presence and locations of nanoplastics on the electrode surface. This study highlights the combination of electrophoresis and QCM effectiveness in detecting nanoplastics across different water types and their potential for broader applications in environmental monitoring.

High-sensitivity fluorescent probes provide a powerful tool for understanding life processes and functioning mechanisms. Therefore, the development of a universal strategy to optimize probes holds substantial importance. Herein, we developed a novel strategy for common probe upgrades: rather than simply pursuing a higher fluorescence intensity of the probe itself, we tried to promote the detection sensitivity by enhancing the probe-substrate interactions. Fortified with polyionic polymers, self-assembled probes could be endowed with enhanced attractions to the substrate. In this work, we took the AChE-AuNCs detection system as a typical and important example to verify this concept of the "enrichment-enhanced detection" strategy (EED strategy). Two probes, AuNCs@GC and AuNCs@CMCS, with similar composing polymers (chitosan derivatives), microstructures, fluorescence profiles, and distinct charges were delicately designed and thoroughly studied. CMCS with an abundance of negatively charged carboxy groups plays an important role in the enrichment of thiocholine through electrostatic interactions. Thus, despite having similar composing components, structures, and almost identical fluorescence profiles, the negatively charged composite shows superior sensitivity (15.2-fold enhancement) and response time (2-fold faster) compared to the AuNCs@GC, thereby validating the feasibility of the EED strategy. Overall, our work validates the EED strategy and applies it to the accurate detection of AChE activity. We believe that this strategy offers substantial insights for the generalization and enhancement of advanced nanoprobes.

Aging is a critical global issue that contributes to the high incidence of Alzheimer's disease (AD). Blood screening emerges as the most promising measure for early diagnosis and intervention of AD due to its noninvasive and low cost. However, the practical application of AD blood screening confronts two significant challenges. First, due to the blood-brain barrier, the concentration of AD biomarkers in blood is much lower than that in cerebrospinal fluid. Second, simultaneous quantitative analysis of multiple biomarkers is necessary due to the low specificity of individual biomarkers. Herein, we propose DNAzyme-based 3D DNA walkers for the sensitive and multiplex detection of five AD-associated miRNA biomarkers: hsa-miR-125b, hsa-miR-342-3p, hsa-miR-29b, hsa-miR-191-5p, and hsa-miR-7d-5. The DNAzyme-based 3D DNA walkers provide highly efficient and autonomous amplification of the minimal biomarkers' quantities. The walking-released metal isotopes ⁸⁹Y, ¹⁶⁵Ho, ¹³⁹La, ¹⁴⁰Ce, and ¹⁵⁹Tb can be sensitively detected by elemental mass spectrometry without any spectral overlap. The detection limit was achieved to be as low as 1.0 fmol. The proposed method was successfully applied to human serum samples with satisfactory spiked recoveries. With its high sensitivity and multiplexity capabilities, this metal isotope strategy may contribute to the early diagnosis and intervention of AD.