Mass-Spectrometry-Based Assay at Single-Base Resolution for Simultaneously Detecting m6A and m6Am in RNA.

The methylation modifications of adenosine, especially N6-methyladenosine (m6A) and N6, 2'-odimethyladenosine (m6Am), play vital roles in various biological, physiological, and pathological processes. However, current methods for detecting these modifications at single-base resolution have limitations. Mass spectrometry (MS), a highly accurate and sensitive technique, can be utilized to differentiate between m6A and m6Am by analyzing the molecular weight differences in their fragments during tandem MS analysis. In this study, we present an MS-based method that allows for the simultaneous determination of m6A and m6Am sites in targeted RNA fragments at single-nucleotide resolution. The approach involves the utilization of tandem MS in conjunction with targeted RNA enrichment and enzymatic digestion, eliminating the need for PCR amplification. By employing this strategy, we can accurately identify m6A and m6Am sites in targeted RNA fragments with high confidence. To evaluate the effectiveness of our method, we applied it to detect m6A and m6Am sites in cell and tissue samples. Furthermore, we verified the accuracy of our approach by performing CRISPR/Cas9-mediated knockout of the corresponding methyltransferases. Overall, our MS-based method offers a reliable and precise means for the simultaneous detection of m6A and m6Am modifications in targeted RNA fragments, providing valuable insights into the functional characterization of these modifications in various biological contexts.

Boosting Electrochemiluminescence Performance of a Dual-Active Site Iron Single-Atom Catalyst-Based Luminol-Dissolved Oxygen System via Plasmon-Induced Hot Holes.

Due to the commonly low content of biomarkers in diseases, increasing the sensitivity of electrochemiluminescence (ECL) systems is of great significance for in vitro ECL diagnosis and biodetection. Although dissolved O2 (DO) has recently been considered superior to H2O2 as a coreactant in the most widely used luminol ECL systems owing to its improved stability and less biotoxicity, it still has unsatisfactory ECL performance because of its ultralow reactivity. In this study, an effective plasmonic luminol-DO ECL system has been developed by complexing luminol-capped Ag nanoparticles (AgNPs) with plasma-treated Fe single-atom catalysts (Fe-SACs) embedded in graphitic carbon nitride (g-CN) (pFe-g-CN). Under optimal conditions, the performance of the resulting ECL system could be markedly increased up to 1300-fold compared to the traditional luminol-DO system. Further investigations revealed that duple binding sites of pFe-g-CN and plasmonically induced hot holes that disseminated from AgNPs to g-CN surfaces lead to facilitate significantly the luminous reaction process of the system. The proposed luminol-DO ECL system was further employed for the stable and ultrasensitive detection of prostate-specific antigen in a wide linear range of 1.0 fg/mL to 1 µg/mL, with a pretty low limit of detection of 0.183 fg/mL.

Machine Learning-Based Label-Free SERS Profiling of Exosomes for Accurate Fuzzy Diagnosis of Cancer and Dynamic Monitoring of Drug Therapeutic Processes.

Exosomes are a class of extracellular vesicles secreted by cells, which can be used as promising noninvasive biomarkers for the early diagnosis and treatment of diseases, especially cancer. However, due to the heterogeneity of exosomes, it remains a grand challenge to distinguish accurately and reliably exosomes from clinical samples. Herein, we achieve accurate fuzzy discrimination of exosomes from human serum samples for accurate diagnosis of breast cancer and cervical cancer through machine learning-based label-free surface-enhanced Raman spectroscopy (SERS), by using "hot spot" rich 3D plasmonic AuNPs nanomembranes as substrates. Due to the existence of some weak distinguishable SERS fingerprint signals and the high sensitivity of the method, the machine learning-based SERS analysis can precisely identify three (normal and cancerous) cell lines, two of which are different types of cancer cells, without specific labeling of biomarkers. The prediction accuracy based on the machine learning algorithm was up to 91.1% for the discrimination of different cell lines (H8, HeLa, and MCF-7 cell)-derived exosomes. Our model trained with SERS spectra of cell-derived exosomes could reach 93.3% prediction accuracy for clinical samples. Furthermore, the action mechanism of the chemotherapeutic process of MCF-7 cells can be revealed by dynamic monitoring of SERS profiling of the exosomes secreted. The method would be useful for noninvasive and accurate diagnosis and postoperative assessment of cancer or other diseases in the future.

Solid-Phase Pyrolysis Synthesis of Highly Fluorescent Nitrogen/Sulfur Codoped Graphene Quantum Dots for Selective and Sensitive Diversity Detection of Cr(VI).

In this study, a simple one-step solid-phase pyrolysis synthesis procedure was employed to prepare N and S codoped highly fluorescent graphene quantum dots (N/S-GQDs). The as-synthesized quantum dot showed λexcitation-dependent blue fluorescence (FL) emission with a relative quantum yield of about 22% and displayed good biocompatibility, high water dispersibility, and excellent stability under extreme conditions (i.e., ionic strength, pH, and temperature). The potential applicability of the as-synthesized quantum dot was tested by employing solution- and paper-based FL detection modes for Cr(VI) detection. The proposed solution- and paper-based FL sensors showed lower limit of detection (LOD) values of 0.01 and 0.4 µM, respectively. The as-constructed paper- and solution-based FL sensors proved the feasibility of sensitive, cost-effective, and on-site detection of Cr(VI).

The efficacy of CO2 laser in the treatment of genitourinary syndrome of menopause: a systematic review and meta-analysis of randomized controlled trials.

CO2 laser has been proposed as a treatment strategy for genitourinary syndrome of menopause (GSM). In order to assess its efficacy for treating GSM, we conducted a systematic review and meta-analysis. To identify the current state of randomized controlled trials on CO2 laser therapy for GSM, a literature review was conducted. We systematically searched the following databases: PUBMED, EMBASE and the Cochrane Controlled Trials Register. In addition, a review of the references in the retrieved studies was carried out. Of 562 identified studies, 9 were eligible and were included in our analysis, involving 523 patients in total. Based on our analysis, CO2 laser has no statistical difference compared with estrogen in VHI (p = 0.87), FSFI total score (p = 0.19), FSFI-Arousal (p = 0.11), FSFI-Desire (p = 0.72), FSFI-Orgasm (p = 0.45) and FSFI-Satisfaction (p = 0.08). The meta-analysis also showed that CO2 laser significantly improved FSFI-Lubrication scores compared with estrogen therapy (p = 0.0004). Furthermore, compared with the sham group, CO2 laser group had statistically improved VHI scores (p = 0.003) and FSFI scores (p < 0.00001). CO2 laser therapy may be an effective alternative to estrogen therapy for GSM both in cases where estrogen is not applicable because of comorbidities and in cases in which women do not desire to take estrogen.

Plasmon-Boosted Fe, Co Dual Single-Atom Catalysts for Ultrasensitive Luminol-Dissolved O2 Electrochemiluminescence Detection of Prostate-Specific Antigen.

Improving the sensitivity of electrochemiluminescence (ECL) systems is highly desired for in vitro ECL diagnosis and bio-detections due to the often-low content of biomarkers in diseases. And dissolved O2 (DO) as a co-reactant is considered superior to H2O2 in the most commonly used luminol ECL systems due to better stability and low biotoxicity, but it still suffers from low ECL performance due to the low reactivity of DO. In this study, an efficient luminol-DO ECL system was developed through the complexing of Fe, Co dual single-atom catalysts (D-SACs) supported by N-doped graphene with the luminol-capped Ag nanoparticles (AgNPs). Benefiting from the electronic interaction between Fe and Co metal sites in the relevant D-SACs and plasmon enhancement of AgNPs, the performance of the corresponding ECL system could be significantly boosted up to ≈677-fold under optimal testing conditions, comparable to the classic luminol-O2 system. Furthermore, the developed luminol-DO ECL system was successfully applied for the stable ultrasensitive detection of prostate-specific antigen (PSA) in a wide linear range of 1 fg/mL to 1 µg/mL, with a low limit of detection (0.98 fg/mL).

Plasmon-Enhanced Nitrogen Vacancy-Rich Carbon Nitride Electrochemiluminescence Aptasensor for Highly Sensitive Detection of miRNA.

The development of biosensors for biologically important substances with ultralow content such as microRNA is of great significance. Herein, a novel surface plasmon-enhanced electrogenerated chemiluminescence-based aptasensor was developed for ultrasensitive sensing of microRNA by using nitrogen vacancy-rich carbon nitride nanosheets as effective luminophores and gold nanoparticles as plasmonic sources. The introduction of nitrogen vacancies improved the electrochemiluminescence behavior due to improved conductance and electrogenerated chemiluminescence activity. The introduction of plasmonic gold nanoparticles increased the electrochemiluminescence signal intensity by more than eightfold. The developed surface plasmon-enhanced electrogenerated chemiluminescence aptasensor exhibited good selectivity, ultrasensitivity, excellent stability, and reproducibility for the determination of microRNA-133a, with a dynamic linear range of 1 aM to 100 pM and a limit of detection about 0.87 aM. Moreover, the surface plasmon-enhanced electrogenerated chemiluminescence sensor obtained a good recovery when detecting the content of microRNA in actual serum.

Surface-Bonding-Enhanced Self-Co-Reactant Electrogenerated Chemiluminescence for Sensitive and Selective Detection of Thioglycolic Acid in Cosmetics.

Thioglycolic acid (TGA) is an organic compound widely used in cosmetics that cause a variety of health problems when overexposed to it. So far many attempts have been made to develop methods for TGA detection, but most of them need sophisticated instrumentations and are a little bit complicated. Therefore, a simple, cheap and sensitive detection method of TGA is highly desired. Herein, we demonstrated for the first time an Au-S bonding amplified, highly sensitive electrochemiluminescence (ECL) sensing method for TGA detection using tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3 2+ ) as a luminophore and TGA as a self-co-reactant, via an anodic reaction at the Au electrode surface. Due to different molecular coordination environments of the TGA at the electrode surface, the ECL signal intensity of the developed ECL system gives much higher ECL signal in borate buffer than phosphate buffer of the same pH. Under the optimized experimental conditions, the ECL intensity has a direct relationship with the concentration of TGA in the range of 0.03 µM to 300 µM and a limit of detection of 0.013 µM (3σ/m). The reported ECL system has further been applied for the detection of TGA in cosmetics with acceptable recoveries.

Wet-Chemical Electro-Plasmonic Modulation of Metasurfaced Cell-Electrode Interfaces for Effective and Selective Entropic Killing of Cancer Cells.

Surface plasmons (SPs) of metallic nanostructures excited by optical ways have been extensively utilized for versatile sensing, biomedical, catalysis, and energy conversion applications. Nevertheless, utilizing the electrically excited plasmonic field (effect) of metallic nanostructures (and electrodes) in wet-chemical conditions, for catalytic and energy conversion, especially for potential biological and biomedical applications, is still poorly studied. Herein, we report a conceptual and biocompatible wet-chemical platform and approach to utilize the electrically excited plasmonic field (effect) of metasurfaced plasmonic electrodes (without light irradiation) for cell fate regulation on electrode surfaces. By using self-assembled two-dimensional (2D) ordered-plasmonic AuNP- or Au@SiO2 NP-nanomembrane as a metasurfaced electrode, the cancer cells cultured on it can be selectively and effectively killed (due to the enhanced stimulus current and related entropic effects) via wet-chemical electro-plasmonic modulation (WC-EPM) of the cell-electrode interfaces. Biological conformational and configurational entropic change information from the cell membrane during the WC-EPM of the cell-electrode interface has also been revealed by label-free in situ surface-enhanced Raman spectroscopy. The developed approach and results can be guides for the WC-EPM regulation of biological interfaces to achieve cell fate regulation and disease treatment and is also constructive for the design of 2D plasmonic nanomaterials and devices for efficient electrochemical energy conservation and biomedical applications.

Two-Dimensional-Plasmon-Boosted Iron Single-Atom Electrochemiluminescence for the Ultrasensitive Detection of Dopamine, Hemin, and Mercury.

Single-atom catalysts (SACs) have recently been exploited for luminol-dissolved oxygen electrochemiluminescence (ECL); however, they still suffer from low sensitivity and narrow detection range for a real sample assay. In this work, we boost markedly the ECL response of the iron SAC (Fe-SAC)-based system, for the first time, by the excitation of two-dimensional plasmons derived from the Au@SiO2 nanomembrane. The plausible mechanism of plasmon enhancement in the Fe-SAC ECL system has been discussed. The constructed Fe-SAC ECL system has been applied for the ECL detection of dopamine, hemin, and mercury (Hg2+), with pretty low limits of detection of 0.1, 0.7, and 0.13 nM and wider linear ranges of 0.001-1.0, 0.001-10, and 0.01-0.5 nM, respectively, under optimal conditions.

Light Scattering and Luminophore Enrichment-Enhanced Electrochemiluminescence by a 2D Porous Ru@SiO2 Nanoparticle Membrane and Its Application in Ultrasensitive Detection of Prostate-Specific Antigen.

Electrochemiluminescence (ECL) by virtue of its controllability and versatility has emerged as a significant tool in bioassay, but how to integrate it with other (nano)materials and further break the limit of sensitivity for ultrasensitive detection still possess tremendous potential. Herein, a close-packed Ru@SiO2 NP nanomembrane that serves as an enhanced substrate and luminophore enricher simultaneously was constructed by the liquid-liquid interface self-assembly method and applied for ECL-enhanced bioassay. The developed ECL electrode obtained ∼600-fold enhancement on ECL intensity compared with the bare ITO electrode and ∼21-fold enhancement compared with the SiO2 NP nanomembrane electrode due to the dramatic light scattering of the 2D SiO2 NPs and the enrichment of Ru(bpy)32+ molecules on the surface of the Ru@SiO2 NP nanomembrane electrode. Based on the fascinating Ru@SiO2 NP nanomembrane platform, we further constructed a label-free immunosensor for the detection of prostate-specific antigen (PSA). The as-fabricated Ru@SiO2-nanomembrane ECL immunosensor exhibited good stability and performed ultrasensitive detection with an utmost low detection limit of 0.169 fg·mL-1 (signal/noise = 3). Our work puts forward an effective solution benefiting for further improving ECL performance for ultrasensitive bioassays.

Plasmon-Boosted Cu-Doped TiO2 Oxygen Vacancy-Rich Luminol Electrochemiluminescence for Highly Sensitive Detection of Alkaline Phosphatase.

In this study, an effective oxygen vacancy (Ov)-involved luminol-dissolved oxygen (O2) electrochemiluminescence (luminol-DO ECL) system was developed and exploited for ECL sensing applications through significant plasmon enhancement of the Ov-involved weak luminol-DO ECL signals by the combined use of Cu-doped TiO2 oxygen vacancy and a Au@SiO2 nanomembrane. The results disclosed that the ECL response of the corresponding system could be synergistically boosted, and the plausible underlying mechanism has been discussed. Furthermore, for the first time, the developed system has been successfully applied for the highly sensitive detection of alkaline phosphatase with a low limit of detection of 0.005 U/L, with an excellent linear range from 0.005 to 10 U/L, as well as good stability and reproducibility.

Effects of heavy metals on bacterial community structures in two lead-zinc tailings situated in northwestern China.

We evaluated the variations of bacterial communities in six heavy metal contaminated soils sampled from Yanzi Bian (YZB) and Shanping Cun (SPC) tailings located in northwestern China. Statistical analysis showed that both the heavy metals and soil chemical properties could affect the structure and diversity of the bacterial communities in the tailing soils. Cd, Cu, Zn, Cr, Pb, pH, SOM (soil organic matters), TP (total phosphorus) and TN (total nitrogen) were the main driving factors of the bacterial community variations. As a consequence, the relative abundances of certain bacterial phyla including Proteobacteria, Chloroflexi, Firmicutes, Nitrospirota and Bacteroidota were significantly increased in the tailing soils. Further, we found that the abundance increasement of these phyla were mainly contributed by certain species, such as s__unclassified_g__Thiobacillus (Proteobacteria), s__unclassified_g__Sulfobacillus (Firmicutes) and Leptospirillum ferriphilum (Nitrospirota). Thus, these species were considered to be strongly heavy metal tolerant. Together, our findings will provide a useful insight for further bioremediations of these contaminated areas.

Electrochemiluminescence of Ru(bpy)32+/thioacetamide and its application for the sensitive determination of hepatotoxic thioacetamide.

Thioacetamide (TAA) is a well-known hepatotoxic substance, so it is important to determine its presence and content in food and environmental samples. Herein, we report a highly sensitive determination method for TAA based on the electrochemiluminescence (ECL) of tris(2,2'-bipyridyl)ruthenium(ii) (Ru(bpy)32+) for the first time by using TAA as a new coreactant for Ru(bpy)32+ ECL via an anodic route. The developed Ru(bpy)32+-TAA ECL system allows the determination of TAA with a good dynamic linear range and low limit of detection (LOD) of 0.1 µM to 1000 µM and 0.035 µM (3σ/m), respectively. In addition, the established ECL system can be applied to detect TAA in fruit juice and waste water samples with outstanding recoveries.

Quasi-Photonic Crystal Light-Scattering Signal Amplification of SiO2-Nanomembrane for Ultrasensitive Electrochemiluminescence Detection of Cardiac Troponin I.

Signal amplification for electrochemiluminescence (ECL) plays a significant role in ultrasensitive detection of disease biomarkers. We report herein a new signal amplification strategy-quasi-photonic crystal nanomembrane-based light scattering enhancement for ECL signal amplification, via fabricating a novel close-packed monolayered SiO2-nanomembrane as solid-state ECL electrodes. In the system, the quasi-photonic crystal structure of the monolayered SiO2-nanomembrane led to intense light scattering within the nanofilm, which significantly increases the photon flux and then definitely improves the excitation number of the luminescent molecules (Ru(bpy)32+). Reinforced by the nanostructured electrode surface of the nanomembrane, the as-prepared ECL electrode exhibited significant ECL enhancement, ∼77-fold enhancement in the classic Ru(bpy)32+-TPrA system. We further constructed a sandwich-type SiO2-nanomembrane based solid-state ECL immunobiosensor for ultrasensitive detection of cardiac troponin I (cTnI). Under optimal conditions, the immunobiosensor exhibited a very low limit of detection (LOD) of 5.6 fg mL-1 for cTnI. Due to the cheap and easy availability of the materials, this study and findings not only provide an efficient way to improve the ECL intensity but also benefit the design of novel ECL electrodes for various biomarker detections.

Efficient Electrogenerated Chemiluminescence of Tris(2,2'-bipyridine)ruthenium(II) with N-Hydroxysulfosuccinimide as a Coreactant for Selective and Sensitive Detection of l-Proline and Mercury(II).

Developing rapid, specific, and low-cost electrogenerated chemiluminescence (ECL) systems remains a compelling goal for many applications including environmental analysis, clinical diagnostics, and food safety. In this study, N-hydroxysuccinimide (NHS) esters, especially N-hydroxysulfosuccinimide (NHSS), was exploited for the first time as an efficient coreactant for anodic Ru(bpy)32+ ECL in neutral medium. Among the three tested NHS esters (NHS, NHSS, NHPI), the NHSS exhibited much higher ECL intensity and stability than the sulfonate-free esters, suggesting the essential role of both the N-hydroxy (NOH) and sulfonate (SO3H) moieties in the developed Ru(bpy)32+ ECL system. The ECL generation process is rather straightforward, not requiring time-consuming fabrication/modification steps of electrodes. The anodic Ru(bpy)32+-NHSS system achieved ECL detections with high selectivity and sensitivity toward l-proline (LOD = 50 nM) and Hg2+ (LOD = 10 nM), with a linear range of 0.5-200 µM and 0.1-25 µM, respectively. The method showed good recoveries (95.2-104.8%) for l-proline and Hg2+ detection in real samples. This study is a successful step toward the development of new coreactants and may open new avenues for the applications of N-hydroxy compounds in ECL sensing.

Lucigenin-Tris(2-carboxyethyl)phosphine Chemiluminescence for Selective and Sensitive Detection of TCEP, Superoxide Dismutase, Mercury(II), and Dopamine.

Development of simple and effective chemiluminescence (CL) systems for multiple sensing applications is significantly important but still a challenge. Until now, the majority of CL systems primarily utilized hydrogen peroxide (H2O2) as coreactant, which is limited in its stability and selectivity due to the easy decomposition of H2O2 in the presence of several ions. In this study, we develop a new and intense CL system by combined use of tris(2-carboxyethyl)phosphine (TCEP), a highly solution stable and pH-tolerant tertiary phosphine, with lucigenin for the first time. The effective pairing leads to a significant ∼23 times CL enhancement over classic the lucigenin-H2O2 system without employing additional catalysts. By virtue of this fascinating platform, a sensitive CL method has been developed for the multiple detection of TCEP (LOD = 70 nM), lucigenin (LOD = 4.0 nM), superoxide dismutase (LOD = 0.8 ng/mL), Hg2+(LOD = 0.3 nM), and dopamine (LOD = 3.0 nM), with a linear range of 0.1-320 µM, 0.01-55 µM, 0.005-0.5 µg/mL, 1.0-600 nM, and 0.01-0.8 µM, respectively. Remarkably, this CL method exhibited superior selectivity over several potential interferents. Moreover, the proposed method achieved excellent recoveries in the range of 94.0-102.3% for both Hg2+ detection in lake water and dopamine detection in human serum real samples. We envision that broad applications of TCEP may lead to construct new CL systems, pushing forward for efficient detection of various analytes.

Smart Plasmonic Nanozyme Enhances Combined Chemo-photothermal Cancer Therapy and Reveals Tryptophan Metabolic Apoptotic Pathway.

Regulation of the tumor microenvironment is considered to be an intelligent strategy for cancer therapeutics, but the related metabolic pathways of cell apoptosis still remain a great challenge. Herein, by applying multifunctional carbon dot-decorated Ag/Au bimetallic nanoshells (CDs-Ag/Au NSs, CAANSs) nanoprobes as smart plasmonic nanozymes for combined chemo-photothermal cancer therapy, we achieved a high efficiency in cancer cell therapy and revealed a tryptophan (Trp) metabolic apoptotic pathway. In addition to high photothermal conversion efficiency, the CAANSs can act as a smart nanozyme to catalyze intracellular H2O2 to the cytotoxic reactive oxygen species (ROS) of superoxide anion (·O2-), in response to mild acidic cancerous cell microenvironment to damage cellular DNA. More importantly, the Trp metabolic pathway during the combined chemo-photothermal therapy has revealed that the Trp participates in an oxidative stress process, which can be decomposed to produce H2O2 and further formed into superoxide anions to kill cells under the catalytic nanomedicine process. The current work provides an effective platform for cancer therapeutics and is promising for cancer-related molecular biology studies.

Smart Plasmonic Nanorobot for Real-Time Monitoring Cytochrome c Release and Cell Acidification in Apoptosis during Electrostimulation.

Cytochrome c (Cyt c) release and cellular pH change are two important mediators of apoptosis. Effective methods to regulate or monitor such two events are therefore highly desired for apoptosis research and cancer cell therapy. Herein, we exploited electrostimulation to regulate cellular Cyt c release and apoptosis process, and by designing and preparing a smart and efficient plasmonic nanorobot (with surface-modified Cyt c-specific aptamer and 4-mercaptobenzoic acid) that is capable of Cyt c capture and self-sensing, we achieved real-time SERS monitoring of dynamic Cyt c release and simultaneous cell acidification in apoptosis during electrostimulation. Distinctly different molecular stress responses in the two events for cancerous MCF-7 and HeLa cells and normal L929 cells were identified and revealed. The method and results are valuable and promising for apoptosis and Cyt c-mediated biology studies.

Living-Cell Imaging of Mitochondrial Membrane Potential Oscillation and Phenylalanine Metabolism Modulation during Periodic Electrostimulus.

Special electrosensory cells are sensitive to electric fields and give responses upon stimulation, but little is known about normal regular cells and cancerous cells. Herein, by designing nucleus- and mitochondria-targeting SERS nanoprobes combined with fluorescent monitoring of the mitochondrial membrane potential (MMP) variations, we found an interesting electrosensory and self-healing response in MMP within cancerous and normal cells during periodic impulse electrostimulation (IES). More importantly, the key regulator role of phenylalanine (phe) was revealed by cell fluorescent imaging and SERS detection, whose expression level was increased in response to IES to induce cell apoptosis. During IES off-state, the self-repair function of cells was activated to reduce phe release. We also found that cancerous cells (MCF-7 and HeLa cells) demonstrated a response more remarkable than that of normal cells (L929 and H8 cells) to periodic IES. Our finding revealed a common electrosensory and self-repair biofunction of cells and its related phe metabolism response. Understanding the difference of biophysical/electrophysiological responses between cancerous and normal cells may broaden the view for cancer therapy in the future.