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Recently, physical tools for remotely stimulating mechanical force‐sensitive and temperature‐sensitive proteins to regulate intracellular pathways have opened up novel and exciting avenues for basic research and clinical applications. Among the numerous modes of physical stimulation, magnetic stimulation is significantly attractive for biological applications due to the advantages of depth penetration and spatial‐temporally controlled transduction. Herein, the physicochemical parameters (e.g., shape, size, composition) that influence the magnetic properties of magnetic nanosystems as well as the characteristics of transient receptor potential vanilloid‐1 (TRPV1) and transient receptor potential vanilloid‐4 (TRPV4) channels are systematically summarized, which offer opportunities for magnetic manipulation of cell fate in a precise and effective manner. In addition, representative regulatory applications involving magnetic nanosystem‐based TRPV1 and TRPV4 channel activation are highlighted, both at the cellular level and in animal models. Furthermore, perspectives on the further development of this magnetic stimulation mode are commented on, with emphasis on scientific limitations and possible directions for exploitation. This article is categorized under:Diagnostic Tools > BiosensingDiagnostic Tools > In Vivo Nanodiagnostics and Imaging [ABSTRACT FROM AUTHOR]

Abstract Cardiac‐cerebral vascular diseases (CCVDs) are acknowledged as a major threat to public health, leading to more than one‐third of all deaths worldwide. The complex anatomical structure and immune features of blood vessels significantly affect the development of CCVDs, and magnetic resonance angiography (MRA) is one of the main diagnostic approaches for the accurate diagnosis and prognosis of CCVDs. However, MRA suffers from intrinsic problems derived from its blood flow‐dependency, and the clinical Gd‐chelating contrast agents are limited by their rapid vascular extravasation. Over the past decade, spurred on by nanoscience and nanotechnology, numerous contrast agents based on magnetic nanomaterials have been developed to enhance the contrast of MRA, with these including iron oxide nanoparticles, rare earth‐doped nanoparticles, and metal‐organic coordination polymers. The molecular MR imaging of vasculopathy using specific nanoprobes has been explored to obtain a better understanding of the molecular aspects of CCVDs. In this review, the state of the art in MRA nanoprobes is introduced, and recent achievements in the diagnosis of CCVDs using MR imaging are summarized. Additionally, the future prospects and limitations of MRA based on nanoprobes are discussed. The current review provides methodological designs and ideas for subsequent MRA nanoprobes.

Abstract Efficient thrombolysis in time is crucial for prognostic improvement of patients with acute arterial thromboembolic disease, while limitations and complications still exist in conventional thrombolytic treatment methods. Herein, our study sought to investigate a novel dual-mode strategy that integrated ultrasound (US) and near-infrared light (NIR) with establishment of hollow mesoporous silica nanoprobe (HMSN) which contains Arginine-glycine-aspartate (RGD) peptide (thrombus targeting), perfluoropentane (PFP) (thrombolysis with phase-change and stable cavitation) and indocyanine green (ICG) (thrombolysis with photothermal conversion). HMSN is used as the carrier, the surface is coupled with targeted RGD to achieve high targeting and permeability of thrombus, PFP and ICG are loaded to achieve the collaborative diagnosis and treatment of thrombus by US and NIR, so as to provide a new strategy for the integration of diagnosis and treatment of arterial thrombus. From the in vitro and in vivo evaluation, RGD/ICG/PFP@HMSN can aggregate and penetrate at the site of thrombus, and finally establish the dual-mode directional development and thrombolytic treatment under the synergistic effect of US and NIR, providing strong technical support for the accurate diagnosis and treatment of arterial thrombosis. Graphical Abstract

[Display omitted] Colorectal cancer (CRC), a widespread malignancy, is closely associated with tumor microenvironmental hydrogen peroxide (H 2 O 2) levels. Some clinical trials targeting H 2 O 2 for cancer treatment have revealed its paradoxical role as a promoter of cancer progression. Investigating the dynamics of cancer cell H 2 O 2 eustress at the single–cell level is crucial. In this study, non–contact hopping probe mode scanning ion conductance microscopy (HPICM) with high-sensitive Pt–functionalized nanoelectrodes was employed to measure dynamic extracellular to intracellular H 2 O 2 gradients in individual colorectal cancer Caco–2 cells. We explored the relationship between cellular mechanical properties and H 2 O 2 gradients. Exposure to 0.1 or 1 mmol/L H 2 O 2 eustress increased the extracellular to intracellular H 2 O 2 gradient from 0.3 to 1.91 or 3.04, respectively. Notably, cellular F–actin–dependent stiffness increased at 0.1 mmol/L but decreased at 1 mmol/L H 2 O 2 eustress. This H 2 O 2 –induced stiffness modulated AKT activation positively and glutathione peroxidase 2 (GPX2) expression negatively. Our findings unveil the failure of some H 2 O 2 -targeted therapies due to their ineffectiveness in generating H 2 O 2 , which instead acts eustress to promote cancer cell survival. This research also reveals the complex interplay between physical properties and biochemical signaling in cancer cells' antioxidant defense, illuminating the exploitation of H 2 O 2 eustress for survival at the single–cell level. Inhibiting GPX and/or catalase (CAT) enhances the cytotoxic activity of H 2 O 2 eustress against CRC cells, which holds significant promise for developing innovative therapies targeting cancer and other H 2 O 2 - related inflammatory diseases. [ABSTRACT FROM AUTHOR]

The cell plasma membrane, serving as the fundamental barrier separating cells from the extracellular environment, is a complex and dynamic structure that is crucial to cell biology. The super-resolution observation of plasma membrane morphology and dynamics in living cells, facilitated by stimulated emission depletion (STED) microscopy, holds significant importance for advancing the understanding of plasma membrane functions. Due to the photobleaching and unclear target, the development of plasma membrane nanoprobes suitable for STED imaging remains challenging. In this study, we present red fluorescent carbon dots (R-CDs) characterized by amphiphilicity and photostability. As carbon-based nanomaterials, R-CDs exhibit the targeting ability of the cell plasma membrane, resulting in a superior imaging signal-to-noise ratio. Furthermore, R-CDs enable STED imaging of plasma membranes in living cells, achieving a resolution enhancement of at least 3-fold compared to confocal imaging. Leveraging the excellent performance of R-CDs, the dynamic behavior of microstructures such as vesicles on the plasma membrane was successfully observed through time-lapse STED imaging under nanoscale. Hence, R-CDs, as fluorescent nanoprobes with good photostability and biocompatibility, demonstrate significant potential for long-term STED imaging of live-cell plasma membranes and the exploration of plasma membrane dynamics. [ABSTRACT FROM AUTHOR]

Efficient thrombolysis in time is crucial for prognostic improvement of patients with acute arterial thromboembolic disease, while limitations and complications still exist in conventional thrombolytic treatment methods. Herein, our study sought to investigate a novel dual-mode strategy that integrated ultrasound (US) and near-infrared light (NIR) with establishment of hollow mesoporous silica nanoprobe (HMSN) which contains Arginine-glycine-aspartate (RGD) peptide (thrombus targeting), perfluoropentane (PFP) (thrombolysis with phase-change and stable cavitation) and indocyanine green (ICG) (thrombolysis with photothermal conversion). HMSN is used as the carrier, the surface is coupled with targeted RGD to achieve high targeting and permeability of thrombus, PFP and ICG are loaded to achieve the collaborative diagnosis and treatment of thrombus by US and NIR, so as to provide a new strategy for the integration of diagnosis and treatment of arterial thrombus. From the in vitro and in vivo evaluation, RGD/ICG/PFP@HMSN can aggregate and penetrate at the site of thrombus, and finally establish the dual-mode directional development and thrombolytic treatment under the synergistic effect of US and NIR, providing strong technical support for the accurate diagnosis and treatment of arterial thrombosis. [ABSTRACT FROM AUTHOR]

Current diagnostic technique in direct identification of multi‐site plaques and simultaneous assessment of plaque vulnerability remains a challenge, which is crucial for indicating the risk of atherosclerotic cardiovascular diseases (ASCVD). Herein, an osteopontin (OPN)‐specific nanoprobe (OPN Ab‐Au/FeNiPO4@ICG) with both multiple spectra optoacoustic tomography (MSOT) and computed tomography (CT) imaging, is constructed successfully realizing systemic screening of vulnerable plaque. OPN Ab‐Au/FeNiPO4@ICG nanoprobe specifically targeted OPN‐overexpressed foam cells and recognized the vulnerable plaque at the molecular level. In AS mice, CT imaging exhibits that OPN Ab‐Au/FeNiPO4@ICG nanoprobe effectively avoid interference from calcification and accurately visualized AS plaque. MSOT functional imaging results reveals that after the injection of OPN Ab‐Au/FeNiPO4@ICG nanoprobe, the carotid plaque exhibited a much higher MSOT signal than the aortic arch plaque (P = 0.0291). Further pathological analysis displays that the carotid plaque possessed a much higher vulnerability score (P = 0.0247), in agreement with the MSOT signals. More importantly, the linear regression analysis confirms the high correlation between the MSOT signals and plaque vulnerability with R = 0.7095 (P = 0.0216), demonstrating the potential of the proposed nanoprobe in systematic evaluation of plaque vulnerability. This work employs the dual‐model nanoprobe strategy for both plaque localization and vulnerability assessment, greatly advancing the accurate diagnosis of ASCVD. [ABSTRACT FROM AUTHOR]

High hydrogen sulfide (H2S) expression has been shown to play a crucial role in tumor growth and proliferation in colon cancer. So far, most probes used for monitoring H2S offer single‐modal imaging, which makes the collection of accurate information for tumor diagnosis difficult. In the present study, a novel dual‐modal imaging probe in the second near‐infrared (NIR‐II, 950‐1700) window is proposed and constructed by coating a uniform shell of polydopamine (PDA) on the surface of cuprous oxide (Cu2O)‐conjugated downconversion nanoparticles (DCNPs). Of note, DCNP‐Cu2O@PDA is in the "on" state, with emission centered at 1550 nm (irradiation using a 980nm laser) in non‐neoplastic tissues. Colon tumors with endogenous H2S overexpression can induce the in situ transformation of Cu2O to copper sulfide (Cu2‐XS）. Owing to the competitive absorption between Cu2‐XS and DCNPs at a wavelength of 980 nm, the generated DCNP‐Cu2‐XS@PDA exhibits a quenched NIR‐II fluorescence (FL) signal. Meanwhile, Cu2‐XS exhibits a strong absorbance at 1250 nm, enhancing the NIR‐II photoacoustic (PA) signal accompanied by NIR‐II FL attenuation. The switching in PA and FL signals at the tumor site offered "double assurances" for the accurate monitoring of H2S. [ABSTRACT FROM AUTHOR]

A three‐dimensional (3D) plasmonic substrate was developed using gold nanorods (GNRs) onto a tapered fiber surface using optical tweezing. To determine the efficacy of the substrate, Raman spectra of two toxic chemicals Rhodamine 6G (R6G) and Crystal Violet (CV) were studied. The "dip and dry" method was used to adsorb the chemicals along the tapered fiber length. The minimum concentration detected for CV and R6G was 10−12 M. We have reported the characteristics and unique features of the manufactured substrate. [ABSTRACT FROM AUTHOR]

Vancomycin is employed to treat infections caused by gram-positive bacteria. Ensuring precise vancomycin dosages is essential to avoid the emergence of bacterial resistance. In the current study, a fluorescent nanoprobe was designed for vancomycin determination in exhaled breath condensate samples. The nanoprobe was based on carbon dots (CDs) doped with nitrogen, sulfur, phosphorus, and chlorine (NSPCl-doped CDs). Vancomycin significantly reduced the fluorescence of NSPCl-doped CDs and presented a quenching process in the analytical response of the probe within a concentration range of 0.01–2.0 μg mL−1 due to forming a non-fluorescent complex. The nanoprobe's intra-day and inter-day relative standard deviations were 1.4 % and 3.2 %, respectively. This nanoprobe was successfully used to determine vancomycin in the patients receiving this drug collected from the expiratory circuit of the mechanical ventilator.

Abstract Background Mesothelin (MSLN) has been implicated in cancer migration, invasion, and prognosis, making it a potential tumor marker. However, the precise role of MSLN in the migration and invasion of malignant pleural mesothelioma (MPM) remains elusive, and effective noninvasive methods for assessing MSLN status are currently lacking. In this study, we focused on MSLN expression and elucidated the underlying mechanisms by which MSLN regulates migration and invasion in MPM. Building upon this knowledge, we developed an MRI nanoprobe that targets MSLN to assess its status in vitro and in vivo by comparing T2 signal intensity and T2 values on magnetic resonance imaging examinations. This nanoprobe combines the anatomical information obtained from MRI with biological information obtained from MSLN for comprehensive evaluation of MPM. Results Notably, we observed that MSLN expression in the epithelial type of MPM was higher and increased continuously with tumor growth than that in other types. In addition, MSLN upregulation promoted N-cadherin, matrix metalloproteinase-7, and MMP9 expression and resulted in higher migration/invasion ability and shorter survival. We synthesized MSLN-targeted nanoprobes (Fe3O4@SiO2-PEG-MSLN, FSPM) to assess MSLN expression by comparing the T2 signal intensity and T2 value of different cell lines and mice after 14, 28, and 42 days of modeling. Remarkably, MSLN-targeted nanoprobes demonstrated excellent targeting capabilities. In vitro studies revealed a pronounced reduction in T2 signal intensity and T2 values of the epithelial type as the probe concentration increased. In addition, in vivo experiments demonstrated a gradual decline in these parameters over time, particularly in the epithelial type as compared to the biphasic type, corresponding to the dynamic expression patterns of MSLN during different growth stages. Conclusion Our comprehensive research succeeded in confirming the regulatory mechanisms by which MSLN influences migration and invasion. Moreover, we introduced a promising method for monitoring MSLN expression that may help in facilitating the early detection, histological subtype identification, and assessment of migration, invasion, and prognosis in MPM.

Abstract The accurate preoperative diagnosis and tracking of lung adenocarcinoma is hindered by non-targeting and diffusion of dyes used for marking tumors. Hence, there is an urgent need to develop a practical nanoprobe for tracing lung adenocarcinoma precisely even treating them noninvasively. Herein, Gold nanoclusters (AuNCs) conjugate with thyroid transcription factor-1 (TTF-1) antibody, then multifunctional nanoprobe Au-TTF-1 is designed and synthesized, which underscores the paramount importance of advancing the machine learning diagnosis and bioimaging-guided treatment of lung adenocarcinoma. Bright fluorescence (FL) and strong CT signal of Au-TTF-1 set the stage for tracking. Furthermore, the high specificity of TTF-1 antibody facilitates selective targeting of lung adenocarcinoma cells as compared to common lung epithelial cells, so machine learning software Lung adenocarcinoma auxiliary detection system was designed, which combined with Au-TTF-1 to assist the intelligent recognition of lung adenocarcinoma jointly. Besides, Au-TTF-1 not only contributes to intuitive and targeted visualization, but also guides the following noninvasive photothermal treatment. The boundaries of tumor are light up by Au-TTF-1 for navigation, it penetrates into tumor and implements noninvasive photothermal treatment, resulting in ablating tumors in vivo locally. Above all, Au-TTF-1 serves as a key platform for target bio-imaging navigation, machine learning diagnosis and synergistic PTT as a single nanoprobe, which demonstrates attractive performance on lung adenocarcinoma. Graphical Abstract

Despite significant advancements in cancer research, real-time monitoring and effective treatment of cancer through non-invasive techniques remain a challenge. Herein, a novel polydopamine (PDA) nucleic acid nanoprobe has been developed for imaging signal amplification of intracellular mRNA and precise photothermal therapy guidance in cancer cells. The PDA nucleic acid nanoprobe (PDA@DNA) is constructed by assembling an aptamer hairpin (H1) labeled with the Cy5 fluorophore and another nucleic acid recognition hairpin (H2) onto PDA nanoparticles (PDA NPs), which have exceptionally high fluorescence quenching ability and excellent photothermal conversion properties. The nanoprobe could facilitate cellular uptake of DNA molecules and their protection from nuclease degradation. Upon recognition and binding to the intracellular mRNA target, a catalytic hairpin assembly (CHA) reaction occurs. The stem of H1 unfolds upon binding, allowing the exposed H1 to hybridize with H2, forming a flat and sturdy DNA double-stranded structure that detaches from the surface of PDA NPs. At the same time, the target mRNA is displaced and engages in a new cyclic reaction, resulting in the recovery and significant amplification of Cy5 fluorescence. Using thymidine kinase1 (TK1) mRNA as a model mRNA, this nanoprobe enables the analysis of TK1 mRNA with a detection limit of 9.34 pM, which is at least two orders of magnitude lower than that of a non-amplifying imaging nucleic acid probe. Moreover, with its outstanding performance for in vitro detection, this nanoprobe excels in precisely imaging tumor cells. Through live-cell TK1 mRNA imaging, it can accurately distinguish between tumor cells and normal cells. Furthermore, when exposed to 808-nm laser irradiation, the nanoprobe fully harnesses exceptional photothermal conversion properties of PDA NPs. This results in a localized temperature increase within tumor cells, which ultimately triggers apoptosis in these tumor cells. The integration of PDA@DNA presents innovative prospects for tumor diagnosis and image-guided tumor therapy, offering the potential for high-precision diagnosis and treatment of tumors. [ABSTRACT FROM AUTHOR]

Atherosclerosis (AS) is a common cardiovascular disease, and its treatment and prevention have been the focus of medical research. AS an emerging technology, nanotechnology has unique advantages and plays an important role in the prevention, diagnosis and treatment of AS. This paper reviews the latest research on the application of nanotechnology in AS diseases, systematically discusses the role of nanotechnology in the diagnosis and treatment of AS, and comprehensively analyzes the effects of nano-drug carriers based on different surface trimmers, loading diagnostic and therapeutic drugs so as to monitordisease progression of AS and its targeted treatment. The aim is to provide new thought for the clinical treatment of AS. [ABSTRACT FROM AUTHOR]

The accurate preoperative diagnosis and tracking of lung adenocarcinoma is hindered by non-targeting and diffusion of dyes used for marking tumors. Hence, there is an urgent need to develop a practical nanoprobe for tracing lung adenocarcinoma precisely even treating them noninvasively. Herein, Gold nanoclusters (AuNCs) conjugate with thyroid transcription factor-1 (TTF-1) antibody, then multifunctional nanoprobe Au-TTF-1 is designed and synthesized, which underscores the paramount importance of advancing the machine learning diagnosis and bioimaging-guided treatment of lung adenocarcinoma. Bright fluorescence (FL) and strong CT signal of Au-TTF-1 set the stage for tracking. Furthermore, the high specificity of TTF-1 antibody facilitates selective targeting of lung adenocarcinoma cells as compared to common lung epithelial cells, so machine learning software Lung adenocarcinoma auxiliary detection system was designed, which combined with Au-TTF-1 to assist the intelligent recognition of lung adenocarcinoma jointly. Besides, Au-TTF-1 not only contributes to intuitive and targeted visualization, but also guides the following noninvasive photothermal treatment. The boundaries of tumor are light up by Au-TTF-1 for navigation, it penetrates into tumor and implements noninvasive photothermal treatment, resulting in ablating tumors in vivo locally. Above all, Au-TTF-1 serves as a key platform for target bio-imaging navigation, machine learning diagnosis and synergistic PTT as a single nanoprobe, which demonstrates attractive performance on lung adenocarcinoma. [ABSTRACT FROM AUTHOR]

Background: Mesothelin (MSLN) has been implicated in cancer migration, invasion, and prognosis, making it a potential tumor marker. However, the precise role of MSLN in the migration and invasion of malignant pleural mesothelioma (MPM) remains elusive, and effective noninvasive methods for assessing MSLN status are currently lacking. In this study, we focused on MSLN expression and elucidated the underlying mechanisms by which MSLN regulates migration and invasion in MPM. Building upon this knowledge, we developed an MRI nanoprobe that targets MSLN to assess its status in vitro and in vivo by comparing T2 signal intensity and T2 values on magnetic resonance imaging examinations. This nanoprobe combines the anatomical information obtained from MRI with biological information obtained from MSLN for comprehensive evaluation of MPM. Results: Notably, we observed that MSLN expression in the epithelial type of MPM was higher and increased continuously with tumor growth than that in other types. In addition, MSLN upregulation promoted N-cadherin, matrix metalloproteinase-7, and MMP9 expression and resulted in higher migration/invasion ability and shorter survival. We synthesized MSLN-targeted nanoprobes (Fe3O4@SiO2-PEG-MSLN, FSPM) to assess MSLN expression by comparing the T2 signal intensity and T2 value of different cell lines and mice after 14, 28, and 42 days of modeling. Remarkably, MSLN-targeted nanoprobes demonstrated excellent targeting capabilities. In vitro studies revealed a pronounced reduction in T2 signal intensity and T2 values of the epithelial type as the probe concentration increased. In addition, in vivo experiments demonstrated a gradual decline in these parameters over time, particularly in the epithelial type as compared to the biphasic type, corresponding to the dynamic expression patterns of MSLN during different growth stages. Conclusion: Our comprehensive research succeeded in confirming the regulatory mechanisms by which MSLN influences migration and invasion. Moreover, we introduced a promising method for monitoring MSLN expression that may help in facilitating the early detection, histological subtype identification, and assessment of migration, invasion, and prognosis in MPM. [ABSTRACT FROM AUTHOR]

A universal strategy for a rapid colorimetric method for Hg2+ in an aqueous solution is described. The specific binding of Hg2+ (thymine-Hg2+-thymine) with thiolated DNA-functionalized gold nanoparticles (AuNPs) via Au–S bonds increases the spatial hindrance of the AuNP surface, resulting in a weakened catalytic ability of AuNPs to catalyze the reaction between p-nitrophenol and NaBH4. Therefore, the color change time (CCT) of the solution from yellow to colorless becomes longer. Based on the kinetic curve of absorbance over time measured by a UV spectrometer, the level of Hg2+ in aqueous solutions can be easily quantified. A linear relationship between CCT and Hg2+ concentration was obtained in the 10–600-nM range with a detection limit of 0.20 nM, which is much lower than the limit value (10 nM) defined by the US Environmental Protection Agency for Hg2+ in drinking water. The excellent sensitivity comes from CCT as the signal output of the probe, rather than the absorbance or wavelength change used in traditional colorimetric probes as the signal output. [ABSTRACT FROM AUTHOR]

Antibiotic residue and toxic heavy metals in aquaculture have a hazardous impact on human health and environmental safety. So the biggest challenge is designing a powerful detecting tool without harming fisheries and the environment. A novel dual-function silver/graphene quantum dots (Ag@GQDs)-based fluorescence nanosensor was developed to investigate unprecedented sensing strategies for sensitive and selective detection of antibiotics and heavy metals to ensure that they are present in the authorized percentage. Here, the fluorescence nanocomposites achieve a new successful sensitive and rapid detection for Oxytetracycline (OTC) and Erythromycin (ERY) antibiotics with detection limits of 2.714 nM and 3.306 nM, respectively. The proposed strategy provides an efficient detection way of tracing heavy metals Hg, Cd, and Pb with a detection limit of less than 5 ppm. Characterization of nanoprobe was by UV/VIS spectroscopy, X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Transmission electron microscopy (TEM). The compared results were with graphene quantum dots (GQDs), graphene oxide quantum dots (GOQDs), and green synthesized silver nanoparticles (AgNPs) which were made from new extracts of aquatic plants and seaweeds from Edku and Marriott Lake. This novel Fluorescence quenching-based technique is sensitive, selective, less time-consuming and does not need expensive preparations to replace the commonly used chromatographic detecting techniques. [ABSTRACT FROM AUTHOR]

In this work, an "on‐off‐on" nanoprobe for specific detection of Cd2+ was constructed using N‐acetyl‐l‐cysteine (NAC)‐modified CdSe quantum dots (QDs). The prepared CdSe QDs exhibit characteristic green fluorescence. The adsorbed S2− on the surface of CdSe QDs leads to dangling bonds and causes the fluorescence quenching of QDs, where the fluorescence of the system turns "off". When Cd2+ exists, it can react with the adsorbed S2− to form CdS shell, resulting in the fluorescence enhancement of CdSe QDs, where the fluorescence of the system turns "on". Due to the similar lattice structure between CdSe and CdS, CdSe/CdS can be produced by shell deposition, while self‐nucleation of metal sulfide is observed in the presence of other metal ions. Thus, the developed nanoprobe shows high selectivity for Cd2+. Under the optimum sensing conditions, the fluorescence sensing signal of CdSe QDs depends linearly on the Cd2+ in the range of 0.2–9 μM. The limit of detection (LOD) and limit of quantification (LOQ) of this nanoprobe is 27 nM and 90 nM, respectively. Furthermore, the proposed nanoprobe can monitor Cd2+ in drinking water with a recovery rate between 95.82 % and 102.00 %, indicating its good practicability and applicability for real sample analysis. [ABSTRACT FROM AUTHOR]

In this work, an "on‐off‐on" nanoprobe for specific detection of Cd2+ was constructed using N‐acetyl‐l‐cysteine (NAC)‐modified CdSe quantum dots (QDs). The prepared CdSe QDs exhibit characteristic green fluorescence. The adsorbed S2− on the surface of CdSe QDs leads to dangling bonds and causes the fluorescence quenching of QDs, where the fluorescence of the system turns "off". When Cd2+ exists, it can react with the adsorbed S2− to form CdS shell, resulting in the fluorescence enhancement of CdSe QDs, where the fluorescence of the system turns "on". Due to the similar lattice structure between CdSe and CdS, CdSe/CdS can be produced by shell deposition, while self‐nucleation of metal sulfide is observed in the presence of other metal ions. Thus, the developed nanoprobe shows high selectivity for Cd2+. Under the optimum sensing conditions, the fluorescence sensing signal of CdSe QDs depends linearly on the Cd2+ in the range of 0.2–9 μM. The limit of detection (LOD) and limit of quantification (LOQ) of this nanoprobe is 27 nM and 90 nM, respectively. Furthermore, the proposed nanoprobe can monitor Cd2+ in drinking water with a recovery rate between 95.82 % and 102.00 %, indicating its good practicability and applicability for real sample analysis. [ABSTRACT FROM AUTHOR]

Given that cancer mortality is usually due to a late diagnosis, early detection is crucial to improve the patient's results and prevent cancer-related death. Imaging technology based on novel nanomaterials has attracted much attention for early-stage cancer diagnosis. In this study, a new block copolymer, poly(ethylene glycol)-poly(l-lactide) diblock copolymer (PEG-PLLA), was synthesized by the ring-opening polymerization method and thoroughly characterized using Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (H-NMR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The obtained PEG-PLLA was used to prepare nanoparticles encapsulated with perfluoropentane and salicylic acid by the emulsion-solvent evaporation method, resulting in a new dual-mode nano-image probe (PEG-PLLA@SA·PFP). The zeta potential and mean diameter of the obtained nanoparticles were measured using dynamic light scattering (DLS) with a Malvern Zetersizer Nano. The in vitro biocompatibility of the PEG-PLLA nanoparticles was evaluated with cell migration, hemolysis, and cytotoxicity assays. Ultrasonic imaging was performed using an ultrasonic imaging apparatus, and chemical exchange saturation transfer (CEST) MRI was conducted on a 7.0 T animal scanner. The results of IR and NMR confirmed that the PEG-PLLA was successfully synthesized. The particle size and negative charge of the nanoparticles were 223.8 ± 2.5 nm and −39.6 ± 1.9 mV, respectively. The polydispersity of the diameter was 0.153 ± 0.020. These nanoparticles possessed good stability at 4 °C for about one month. The results of cytotoxicity, cell migration, and hemolysis assays showed that the carrier material was biocompatible. Finally, PEG-PLLA nanoparticles were able to significantly enhance the imaging effect of tumors by the irradiation of ultrasound and saturation by a radiofrequency pulse, respectively. In conclusion, these nanoparticles exhibit promising dual-mode capabilities for US/CEST MR imaging. [ABSTRACT FROM AUTHOR]

A surface-enhanced Raman scattering nanoprobe has been developed for sulfide detection and applied to complex bacterial biofilms. The nanoprobe, Au@4-MBN@Ag@ZIF-8, comprised a gold core modified with 4-mercaptobenzonitrile (4-MBN) as signaling source, a layer of silver shell as the sulfide sensitization material, and a zeolitic imidazolate framework-8 (ZIF-8) as surface barrier. ZIF-8, with its high surface area and mesoporous structure, was applied to preconcentrate sulfide around the nanoprobe with its excellent adsorption capacity. Besides, the external wrapping of ZIF-8 can not only prevent the interference of biomolecules, such as proteins, with the Au@4-MBN@Ag assay but also enhance the detection specificity through the sulfide cleavage function towards ZIF-8. These properties are critical for the application of this nanoprobe to complex environmental scenarios. In the presence of sulfide, it was first enriched through adsorption by the outer ZIF-8 layer, then destroyed the barrier layer, and subsequently reacted with the Ag shell, leading to changes in the Raman signal. Through this rational design, the Au@4-MBN@Ag@ZIF-8 nanoprobe exhibited excellent detection sensitivity, with a sulfide detection limit in the nanomolar range and strong linearity in the concentration range 50 nM to 500 μM. Furthermore, the proposed Au@4-MBN@Ag@ZIF-8 nanoprobe was effectively utilized for sulfide detection in intricate biofilm matrices, demonstrating its robust selectivity and reproducibility. [ABSTRACT FROM AUTHOR]

Although the extraordinary progress has been made in molecular biology, the prevention of cancer remains arduous. Most solid tumours exhibit both spatial and temporal heterogeneity, which is difficult to be mimicked in vitro. Additionally, the complex biochemical and immune features of tumour microenvironment significantly affect the tumour development. Molecular imaging aims at the exploitation of tumour‐associated molecules as specific targets of customized molecular probe, thereby generating image contrast of tumour markers, and offering opportunities to non‐invasively evaluate the pathological characteristics of tumours in vivo. Particularly, there are no "standard markers" as control in clinical imaging diagnosis of individuals, so the tumour pathological characteristics‐responsive nanoprobe‐based quantitative molecular imaging, which is able to visualize and determine the accurate content values of heterogeneous distribution of pathological molecules in solid tumours, can provide criteria for cancer diagnosis. In this context, a variety of "smart" quantitative molecular imaging nanoprobes have been designed, in order to provide feasible approaches to quantitatively visualize the tumour‐associated pathological molecules in vivo. This review summarizes the recent achievements in the designs of these nanoprobes, and highlights the state‐of‐the‐art technologies in quantitative imaging of tumour‐associated pathological molecules. [ABSTRACT FROM AUTHOR]

A novel, rapid, selective, ultrasensitive, and ultra-reproducible spectrofluorometric nanoassay was designed for the L-methionine quantification. A carbon dot with a %QY as high as 95% was prepared using a solvent-free ultrafast method and used as the label-free nanoprobe. The nanoprobe was characterized for size, morphology, elemental composition, optical properties, and quantum efficiency. Afterward, the nanoprobe was utilized for quantification of L-methionine in biological samples, revealing an ultra-wide linear range of 0.0–140.0 nm with a LOD as low as 0.65 nM. Besides, the developed method showed ultra-reproducibility with an inter-week assay, of RSD = 2.7% and high repeatability with a RSD as low as 1.0%. The mechanistic studies proved the simultaneous formation of two complexes between CDs and L-methionine, resulting in high sensitivity, selectivity, and stability of the sensor. Moreover, a binding constant as high as 1.4 × 10+6 M−1, number of binding sites of 1.5, and a ∆G of − 35.1 was obtained for interaction between CDs and L-methionine. Finally, the developed method was utilized for analysis of the methionine content of human serum samples for both healthy and patients with homocystinuria for proving its possible application in homocystinuria diagnosis, showing highly accurate and reproducible results. Consequently, the proposed nanoassay can be applied for clinical practical applications toward homocystinuria diagnosis. [ABSTRACT FROM AUTHOR]

The strong fluorescence and high photostability of inorganic quantum dots (QDs) have envisaged them as superior fluorescent probes for biomedical imaging applications compared to organic dyes that are highly prone to photobleaching. However, earlier reports suggest that the potential use of inorganic QDs can be ensured only if they remain fluorescent and stably dispersed in water and other biological fluids under a wide pH range. In the present work, we address in detail the influence of pH (range 1.0–13.0) on the photophysical properties of functionalized tungsten disulfide QDs (f-WS2-QDs) synthesized using a facile, eco-friendly, and single-step hydrothermal approach. Experimental findings suggest that the fluorescence nature of as-produced f-WS2-QDs remains highly stable in harsh acidic to basic media. The PL stability and dispersion of f-WS2-QDs in aqueous media are explained in terms of various functional groups present over the QDs' surface, which causes surface passivation of the QDs during hydrothermal growth leading to the high solubility and stable fluorescence of QDs in aqueous media. Furthermore, as a proof of concept, we have also demonstrated that the f-WS2-QDs could be potentially used as a fluorescent probe for high-contrast in vivo imaging of Drosophila third instar larvae. Thus, we anticipate that the present investigation may provide insight into the scientific community for the development of pH-universal inorganic QDs for biological applications. [ABSTRACT FROM AUTHOR]

Ferroptosis is a non-apoptotic cell death regulated by iron-dependent lipid peroxidation. Glutathione (GSH), a key antioxidant against oxidative damage, is involved in one of the most important metabolic pathways of ferroptosis. Herein, an excellent plasmonic nanoprobe was developed for highly sensitive, in situ, dynamic real-time monitoring of intracellular GSH levels during ferroptosis. A nanoprobe was prepared by functionalizing gold nanoparticles (AuNPs) with the probe molecule crystal violet (CV). The fluctuation in the SERS signal intensity of CV via the competitive displacement reaction can be used to detect GSH. The advantages of the plasmonic nanoprobe including low-cost production techniques, outstanding stability and biocompatibility, high specificity and sensitivity towards GSH with a detection limit of 0.05 μM. It enables real-time dynamic monitoring of GSH levels in living cells during erastin-induced ferroptosis. This approach is expected to provide important theoretical support for elucidating the GSH-related ferroptosis metabolic mechanism and advancing our understanding of ferroptosis-based cancer therapy. [ABSTRACT FROM AUTHOR]

Fe-based single-atomic site catalysts (SASCs), with the natural metalloproteases-like active site structure, have attracted widespread attention in biocatalysis and biosensing. Precisely, controlling the isolated single-atom Fe-N-C active site structure is crucial to improve the SASCs' performance. In this work, we use a facile ion-imprinting method (IIM) to synthesize isolated Fe-N-C single-atomic site catalysts (IIM-Fe-SASC). With this method, the ion-imprinting process can precisely control ion at the atomic level and form numerous well-defined single-atomic Fe-N-C sites. The IIM-Fe-SASC shows better peroxidase-like activities than that of non-imprinted references. Due to its excellent properties, IIM-Fe-SASC is an ideal nanoprobe used in the colorimetric biosensing of hydrogen peroxide (H2O2). Using IIM-Fe-SASC as the nanoprobe, in situ detection of H2O2 generated from MDA-MB-231 cells has been successfully demonstrated with satisfactory sensitivity and specificity. This work opens a novel and easy route in designing advanced SASC and provides a sensitive tool for intracellular H2O2 detection.

Abstract Although the extraordinary progress has been made in molecular biology, the prevention of cancer remains arduous. Most solid tumours exhibit both spatial and temporal heterogeneity, which is difficult to be mimicked in vitro. Additionally, the complex biochemical and immune features of tumour microenvironment significantly affect the tumour development. Molecular imaging aims at the exploitation of tumour‐associated molecules as specific targets of customized molecular probe, thereby generating image contrast of tumour markers, and offering opportunities to non‐invasively evaluate the pathological characteristics of tumours in vivo. Particularly, there are no “standard markers” as control in clinical imaging diagnosis of individuals, so the tumour pathological characteristics‐responsive nanoprobe‐based quantitative molecular imaging, which is able to visualize and determine the accurate content values of heterogeneous distribution of pathological molecules in solid tumours, can provide criteria for cancer diagnosis. In this context, a variety of “smart” quantitative molecular imaging nanoprobes have been designed, in order to provide feasible approaches to quantitatively visualize the tumour‐associated pathological molecules in vivo. This review summarizes the recent achievements in the designs of these nanoprobes, and highlights the state‐of‐the‐art technologies in quantitative imaging of tumour‐associated pathological molecules.

Fluorescence and photoacoustic imaging techniques offer valuable insights into cell- and tissue-level processes. However, these optical imaging modalities are limited by scattering and absorption in tissue, resulting in the low-depth penetration of imaging. Contrast-enhanced imaging in the near-infrared window improves imaging penetration by taking advantage of reduced autofluorescence and scattering effects. Current contrast agents for fluorescence and photoacoustic imaging face several limitations from photostability and targeting specificity, highlighting the need for a novel imaging probe development. This review covers a broad range of near-infrared fluorescent and photoacoustic contrast agents, including organic dyes, polymers, and metallic nanostructures, focusing on their optical properties and applications in cellular and animal imaging. Similarly, we explore encapsulation and functionalization technologies toward building targeted, nanoscale imaging probes. Bioimaging applications such as angiography, tumor imaging, and the tracking of specific cell types are discussed. This review sheds light on recent advancements in fluorescent and photoacoustic nanoprobes in the near-infrared window. It serves as a valuable resource for researchers working in fields of biomedical imaging and nanotechnology, facilitating the development of innovative nanoprobes for improved diagnostic approaches in preclinical healthcare. [ABSTRACT FROM AUTHOR]

A fluorometric and colorimetric dual-modal nanoprobe (denoted as Fe2+-Phen/SiNPs) has been developed for selective and sensitive determination of nitrite (NO2−). The mechanism is based on fluorescence quenching between silicon nanoparticles (SiNPs) and Fe(II)-phenanthroline complex (Fe2+-Phen) via inner filter effect and redox. With the addition of increasing NO2−, Fe2+ is oxidized to Fe3+, recovering the fluorescence of SiNPs. Meanwhile, the color of the system gradually changes from orange-red to colorless, which enables colorimetric measurement. The NO2− concentration shows a wide linear relationship with fluorescence intensity from 0.1 to 1.0 mM (R2 = 0.9955) with a detection limit of 2.4 μM in the fluorometric method (excitation wavelength: 380 nm). By contrast, the linear range of the colorimetric method ranges from 0.01 to 0.35 mM (R2 = 0.9953) with a limit of detection of 6.8 μM (proposed selective absorbance: 510 nm). The probe has been successfully applied to nitrite determination in water, salted vegetables, and hams demonstrating broad application prospects for the determination of nitrite in complicated matrices. [ABSTRACT FROM AUTHOR]

Venous thromboembolism ( VTE), including pulmonary embolism ( PE) and deep vein thrombosis (DVT), is considered as one of the most common cardiovascular diseases in the world, causing a huge social and economic burden. Despite the predominant role in the treatment of VTE, anti-thrombotic therapy has an extremely high risk of bleeding due to its association with blood coagulation and hemolysis system. Therefore, strict monitoring should be performed during the disease progression. However, the existing approaches can not fully meet the needs of precision medicine. Molecular imaging can reflect the disease information at the molecular level. Quantitative monitoring on thrombustargeted nanoprobes through imaging approaches can accurately diagnose disease subtypes and provide personalized treatment. This article reviews the research progress of nanomolecular imaging in the diagnosis and treatment of VTE in recent years, which is expected to provide new ideas for the diagnosis and treatment of VTE. [ABSTRACT FROM AUTHOR]

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Silver nanoparticles (AgNPs) prepared by green synthesis have a lot of potentials in various fields. Among them, as an antioxidant, antibacterial agent, and nanoprobe for the colorimetric detection of mercury (Hg2+) ions is thought to be the most important. The antibacterial, antioxidant, and colorimetric sensing potential of the greenly produced AgNPs utilizing Piper chaba stem extract are all predicted in this investigation. By using the disc diffusion method, the antibacterial activity of greenly produced AgNPs are assessed, and the findings are measured from the zone of inhibition (ZOI). It is revealed that the Staphylococcus aureus, Micrococcus spp., Escherichia coli, and Pseudomonas aeruginosa bacterial strains are significantly resisted by the greenly produced AgNPs. The antioxidant activity test of AgNPs reveals a considerable impact on free radical scavenging having the inhibitory concentration (IC50) is 1.13 mL (equivalent to 0.45 mg mL−1). Also, with a low limit of detection of 28 ppm, the resulting AgNPs are used as highly selective and economical colorimetric sensors for Hg2+ detection. The study's findings support the hypothesis that Piper chaba stems can serve as a source for the production of AgNPs with high antibacterial and antioxidant activity and usefulness for simple colorimetric readings of Hg2+. [ABSTRACT FROM AUTHOR]

Purpose: Achieving new contrast enhancer agents that can produce high-resolution images in magnetic resonance imaging (MRI) with a minimum dose and side effects has always been important. Methods: Herein, the pegylated curcumin-coated manganese–zinc ferrite nanoparticles (MZF@CA-PEG-CUR NPs) have been reported as an MR imaging nanoprobe in hepatocellular carcinoma detection in the murine model for the first time. In vitro studies were done on HEPA 1–6 cancer cells and L929 as normal cells, and in vivo studies were done on hepatocellular carcinoma (HCC) using xenograft models of HCC. Results: The prepared NP had a diameter of 105 nm with narrow size distribution and was superparamagnetic with a saturated magnetization (Ms) of 39 emu/g. The NP was biocompatible without any significant hemolysis and cytotoxicity. Prussian blue staining showed more cellular uptake of HEPA 1–6 compared to L929 control cells after incubation (P < 0.05). The concentration of Fe in mice blood confirmed the plasma half-life of about 3 h; it seems the PEGylation increased the circulation time. ICP-OES of Fe showed the highest tumor localization for MZF@CA-CUR-PEG NPs, due to passive accumulation, compared to the other mice studied organs. The r2 relaxivity of NPs was 134.89 mM− 1 s− 1, and in vitro MRI demonstrated better effects in HEPA 1–6 cells than in L929 (P < 0.05). Also, in vivo MR images showed signal enhancement efficacy in tumor-bearing mice. Conclusion: This study demonstrated that the MZF@CA-CUR-PEG nanoprobe could be a promising candidate as an MR imaging agent in hepatocellular carcinoma early detection. [ABSTRACT FROM AUTHOR]

Studying chemical reactions in an environment that closely mimics the system's natural operating conditions can offer crucial insights into dynamic oxidation processes. Transmission Electron Microscopes (TEMs) and X-ray Nanoprobes allow the use of imaging and spectroscopy to access nanoscale chemical and structural information about these processes. However, the controlled operating conditions and constraints make the design and implementation of in situ sample environments challenging. Here, we outline the setup of an in situ liquid sample environment for the Hard X-ray Nanoprobe beamline (I14) at Diamond Light Source. The liquid environment allows for the imaging and spectroscopic analysis of samples exposed to liquid flow, with heating up to 80℃. The capability is demonstrated with an example experiment studying iron corrosion. The design of the sample cell offers the prospect of combining X-ray and electron microscopy for the in situ multi-length scale imaging and spectroscopy of samples in liquid. [ABSTRACT FROM AUTHOR]

A novel nanoprobe was developed for the detection of hyaluronidase as cancer marker, using fluorescein 5‐isothiocyanate (FITC) as fluorescence indicator, hyaluronic acid (HA), and polyethyleneimine (PEI) functionalized graphene oxide (GO) as quencher. PEI was attached to GO through amide bonding, using 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC) and N‐hydroxysuccinimide (NHS) as coupling agents. Aminated hyaluronic acid (HA) was then linked to GO‐PEI (GOP) via the same route. Nuclear magnetic resonance, ultraviolet–visible–near infrared spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscope, and thermogravimetric analysis analyses confirmed the successful synthesis of GOP‐HA. Finally, FITC was attached to GOP‐HA through reaction between the isothiocyanate group of FITC and the amine group of aminated HA. The fluorescence of FITC is quenched in the resulted GOP‐HA‐FITC nanoprobe. Addition of hyaluronidase can cleave HA chains into small fragments, releasing FITC to emit fluorescence. Importantly, the nanoprobe is highly sensitive and selective, and can enter cells by specifically binding to the CD44 receptor on the surface of Hela cells. Therefore, GOP‐HA‐FITC nanoprobe could be used in targeted tumor cell imaging for the early diagnosis of cancers. [ABSTRACT FROM AUTHOR]

Quercetin can help with a variety of health problems. Most methods for measuring quercetin in biological fluids are characterized by low sensitivity and selectivity. The employment of metal–organic frameworks in sensor applications with carbon-based materials ushers in a new era. In this study, blue fluorescent graphene quantum dots (GQDs) embedded in a UiO-66-NH2 metal–organic framework-based nanoprobe (GQDs@UiO-66-NH2) were constructed for quercetin sensing. Initially, maize husk was used to produce blue fluorescent GQDs, whereas zirconium tetrachloride and 2-aminoterephthalic acid were used to synthesize extremely luminous UiO-66-NH2. The addition of quercetin to GQDs@UiO-66-NH2 leads to fluorescence dampening due to the adsorption potential of UiO-66-NH2. The complexation of zirconium ions with the 3-OH and 4-C＝O functionalities of quercetin resulted in fluorescence quenching. The sensor has a linear concentration range and limit of detection for quercetin of 50–500 and 2.82 ng/mL, respectively. The nanoprobe’s usefulness for quercetin detection was then validated by a selectivity investigation in the presence of interfering chemicals. Furthermore, the percentage relative standard deviations were 4.20% and 2.90%, respectively, indicating great stability and repeatability. Fluorescence “Turn-On–Off” nanoprobes provide a simple, quick, sensitive, and selective method for monitoring quercetin.

Background: Niosomes are primary-bilayer vesicles used in anticancer drugs. The aim of this study is the synthesis of nisome nanocarrier containing Artemisia Annua extract and its anticancer charactersitics. Materials and Methods: This in-vitro study was carried out at the Islamic Azad University, North Tehran Branch, from December 1400 to September 1401. Firstly, a niosomes nanocarrier was synthesized with the thin-layer hydration approach. Then, Artemisia Annua extract was loaded into them. Following that, physical and chemical features of nanocarriers were evaluated utilizing scanning electron microscope (SEM) and dynamic light scattering (DLS). The encapsulation level and the release pattern of the extract were valiadated vi a dialysis bag. Finally, its anticancer effects were investigated on breast cancer cell line (MCF_7). Results: The results showed that the synthesized nanocarrier of nisome containing the extract has a spherical structure and its size was 208.1 nm and the encapsulation percentage was 62.35%. It was also found that the nanocarrier of loaded niosom had significant anticancer effects compared to non-loaded extract. Conclusion: It can be concluded that the nisome-containing Artemisia Annua extract of medicinal plant increases the anti-cancer effects significantly, and therefore, nisome can be used as a targeted drug delivery system for anti-cancer purposes.

The interaction of a focused X-ray beam with a sample in a scanning probe experiment can provide a variety of information about the interaction volume. In many scanning probe experiments X-ray fluorescence (XRF) is supplemented with measurements of the transmitted or scattered intensity using a pixelated detector. The automated extraction of different signals from an area pixelated detector is described, in particular the methodology for extracting differential phase contrast (DPC) is demonstrated and different processing methods are compared across a range of samples. The phase shift of the transmitted X-ray beam by the sample, extracted from DPC, is also compared with ptychography measurements to provide a qualitative and quantitative comparison. While ptychography produces a superior image, DPC can offer a simple, flexible method for phase contrast imaging which can provide fast results and feedback during an experiment; furthermore, for many science problems, such as registration of XRF in a lighter matrix, DPC can provide sufficient information to meet the experimental aims. As the DPC technique is a quantitative measurement, it can be expanded to spectroscopic studies and a demonstration of DPC for spectro-microscopy measurements is presented. Where ptychography can separate the absorption and phase shifts by the sample, quantitative interpretation of a DPC image or spectro-microscopy signal can only be performed directly when absorption is negligible or where the absorption contribution is known and the contributions can be fitted.

Ischemic stroke is one of the leading causes of disability and mortality. The collaterals provide an alternative pathway to preserve the ischemic brain tissue, and determine the penumbra range, where the neurons are salvageable. Therefore, accurately monitoring the collaterals and identifying the penumbra are crucial. Herein, a low-immunogenic nanoprobe-based MRI strategy is developed to simultaneously identify the infarct core, collaterals distribution, and ischemic penumbra distributions. The low-immunogenic nanoprobe was constructed by covalently attaching self-peptide on the surface of biocompatible Fe3O4 nanoparticles as a stealth coating. Both in vitro and in vivo experiments clearly revealed that the nanoprobes can effectively avoid capture by macrophages, and exhibited prolonged blood half-life to continuously enhance the contrast of blood vessels in a longer time window in susceptibility-weighted imaging (SWI), which enabled the delineation of the collaterals and ischemic penumbra. More importantly, combined with the diffusion-weighted imaging (DWI), the infarct core, collateral vessels, and the ischemic penumbra range can be identified simultaneously. In this context, the stroke progress including infarct core growth, collateral vessel formation, and penumbra distribution, can be better understood. This nanoprobe-based strategy thus offers a practical route for precise diagnosis of ischemic stroke, which remains a challenge for conventional MRI strategies.

Abstract Silver nanoparticles (AgNPs) prepared by green synthesis have a lot of potentials in various fields. Among them, as an antioxidant, antibacterial agent, and nanoprobe for the colorimetric detection of mercury (Hg2+) ions is thought to be the most important. The antibacterial, antioxidant, and colorimetric sensing potential of the greenly produced AgNPs utilizing Piper chaba stem extract are all predicted in this investigation. By using the disc diffusion method, the antibacterial activity of greenly produced AgNPs are assessed, and the findings are measured from the zone of inhibition (ZOI). It is revealed that the Staphylococcus aureus, Micrococcus spp., Escherichia coli, and Pseudomonas aeruginosa bacterial strains are significantly resisted by the greenly produced AgNPs. The antioxidant activity test of AgNPs reveals a considerable impact on free radical scavenging having the inhibitory concentration (IC50) is 1.13 mL (equivalent to 0.45 mg mL−1). Also, with a low limit of detection of 28 ppm, the resulting AgNPs are used as highly selective and economical colorimetric sensors for Hg2+ detection. The study's findings support the hypothesis that Piper chaba stems can serve as a source for the production of AgNPs with high antibacterial and antioxidant activity and usefulness for simple colorimetric readings of Hg2+.

Introduction: Fluorescent visualization of hydrogen peroxide in the tumor microenvironment (TME) is conducive to predicting malignant prognosis after chemotherapy. Two photon microscopy has been employed for in vivo hydrogen peroxide detection owing to its advantages of deep penetration and low phototoxicity.Methods: In this study, a two-photon fluorescent probe (TPFP) was protected by mesoporous silica nanoparticles (MSNs) and masked by cloaking the cancer cell membranes (CM), forming a tumor-targeted bioactive nanoprobe, termed MSN@TPFP@CM.Results: This multifunctional nanoprobe allowed for the effective and selective detection of excessive hydrogen peroxide production in chemotherapeutic Etoposide (VP-16)-challenged tumor cells using two-photon microscopy. After specific accumulation in tumors, VP-16-MSN@TPFP@CM monitored tumor-specific hydrogen peroxide levels and revealed a positive correlation between oxidative stress in the TME and chemotherapy-exacerbated malignant prognosis.Discussion: Given the recent translation of fluorescent imaging into early clinical trials and the high biocompatibility of bioactive nanoprobes, our approach may pave the way for specific imaging of oxidative stress in solid tumors after treatment and provide a promising technology for malignant prognosis predictions.

Bioaffinity nanoprobes are a type of biosensor that utilize the specific binding properties of biological molecules, such as antibodies, enzymes, and nucleic acids, for the detection of foodborne pathogens. These probes serve as nanosensors and can provide highly specific and sensitive detection of pathogens in food samples, making them an attractive option for food safety testing. The advantages of bioaffinity nanoprobes include their ability to detect low levels of pathogens, rapid analysis time, and cost-effectiveness. However, limitations include the need for specialized equipment and the potential for cross-reactivity with other biological molecules. Current research efforts focus on optimizing the performance of bioaffinity probes and expanding their application in the food industry. This article discusses relevant analytical methods, such as surface plasmon resonance (SPR) analysis, Fluorescence Resonance Energy Transfer (FRET) measurements, circular dichroism, and flow cytometry, that are used to evaluate the efficacy of bioaffinity nanoprobes. Additionally, it discusses advances in the development and application of biosensors in monitoring foodborne pathogens. [ABSTRACT FROM AUTHOR]

For sensitive analysis of cancer biomarker carcinoembryonic antigen (CEA), an amperometric sandwich‐type aptasensor is proposed based on a signal amplification strategy of Au@Pt bimetallic nanoprobes. As the excellent catalytic activity to hydrogen peroxide (H2O2), core‐shell Au@Pt nanoparticles are employed as nanoprobes by conjugating directly with the secondary aptamer of CEA (Apt‐II). Due to the synergic recognition effect of dual aptamers and the excellent catalytic activity of nanoprobes, this amperometric sandwich‐type aptasensor for CEA exhibits high specificity and good sensitivity with a limit of detection of 0.31 ng/mL, along with a wide linear range from 0.1 ng/mL to 100 ng/mL. [ABSTRACT FROM AUTHOR]

Yijie Lv,1 Junnan Kan,1 Mingfang Luo,2 Changfeng Yang,1 Xunrong Luo,2 Xiaoqian Lin,1 Hao Li,1 Xueming Li,1 Yuping Li,1 Caixia Yang,1 Yan Liu,1 Xianglin Li1 1School of Medical Imaging, Binzhou Medical University, Yantai, Shandong, 264003, People’s Republic of China; 2Department of Radiology, Sichuan Provincial People’s Hospital, Chengdu, Sichuan, 610072, People’s Republic of ChinaCorrespondence: Yan Liu; Xianglin Li, School of Medical Imaging, Binzhou Medical University, Yantai, Shandong, 264003, People’s Republic of China, Tel +86 535 6919135 ; +86 535 6919175, Email liuericyan@hotmail.com; xlli@bzmc.edu.cnIntroduction: Accurate tumor diagnosis is essential to achieve the ideal therapeutic effect. However, it is difficult to accurately diagnose cancer using a single imaging method because of the technical limitations. Multimodal imaging plays an increasingly important role in tumor treatment. Photodynamic therapy (PDT) has received widespread attention in tumor treatment due to its high specificity and controllable photocytotoxicity. Nevertheless, PDT is susceptible to tumor microenvironment (TME) hypoxia, which greatly reduces the therapeutic effect of tumor treatment.Methods: In this study, a novel multifunctional nano-snowflake probe (USPIO@MnO2@Ce6, UMC) for oxygen-enhanced photodynamic therapy was developed. We have fabricated the honeycomb-like MnO2 to co-load chlorin e6 (Ce6, a photosensitizer) and ultrasmall superparamagnetic iron oxide (USPIO, T1-T2 double contrast agent). Under the high H2O2 level of tumor cells, UMC efficiently degraded and triggered the exposure of photosensitizers to the generated oxygen, accelerating the production of reactive oxygen species (ROS) during PDT. Moreover, the resulting USPIO and Mn2+ allow for MR T1-T2 imaging and transformable PAI for multimodal imaging-guided tumor therapy.Results: TEM and UV-vis spectroscopy results showed that nano-snowflake probe (UMC) was successfully synthesized, and the degradation of UMC was due to the pH/ H2O2 responsive properties. In vitro results indicated good uptake of UMC in 4T-1 cells, with maximal accumulation at 4 h. In vitro and in vivo experimental results showed their imaging capability for both T1-T2 MR and PA imaging, providing the potential for multimodal imaging-guided tumor therapy. Compared to the free Ce6, UMC exhibited enhanced treatment efficiency due to the production of O2 with the assistance of 660 nm laser irradiation. In vivo experiments confirmed that UMC achieved oxygenated PDT under MR/PA imaging guidance in tumor-bearing mice and significantly inhibited tumor growth in tumor-bearing mice, exhibiting good biocompatibility and minimal side effects.Conclusion: The multimodal imaging contrast agent (UMC) not only can be used for MR and PA imaging but also has oxygen-enhanced PDT capabilities. These results suggest that UMC may have a good potential for further clinical application in the future.Graphical Abstract: Keywords: photodynamic therapy, oxygen generation, magnetic resonance imaging, photoacoustic imaging, theranostics, nanoprobe

Quercetin can help with a variety of health problems. Most methods for measuring quercetin in biological fluids are characterized by low sensitivity and selectivity. The employment of metal-organic frameworks in sensor applications with carbon-based materials ushers in a new era. In this study, blue fluorescent graphene quantum dots (GQDs) embedded in a UiO-66-NH2 metal-organic framework-based nanoprobe (GQDs@UiO-66-NH2) were constructed for quercetin sensing. Initially, maize husk was used to produce blue fluorescent GQDs, whereas zirconium tetrachloride and 2-aminoterephthalic acid were used to synthesize extremely luminous UiO-66-NH2. The addition of quercetin to GQDs@UiO-66-NH2 leads to fluorescence dampening due to the adsorption potential of UiO-66-NH2. The complexation of zirconium ions with the 3-OH and 4-C=O functionalities of quercetin resulted in fluorescence quenching. The sensor has a linear concentration range and limit of detection for quercetin of 50-500 and 2.82 ng/mL, respectively. The nanoprobe's usefulness for quercetin detection was then validated by a selectivity investigation in the presence of interfering chemicals. Furthermore, the percentage relative standard deviations were 4.20% and 2.90%, respectively, indicating great stability and repeatability. Fluorescence "Turn-On-Off" nanoprobes provide a simple, quick, sensitive, and selective method for monitoring quercetin. [ABSTRACT FROM AUTHOR]

As an emerging hybrid imaging modality, microwave-induced thermoacoustic imaging (MTAI), using microwaves as the excitation source and ultrasonic signals as the information carrier for combining the characteristics of high contrast of electromagnetic imaging and high resolution of ultrasound imaging, has shown broad prospects in biomedical and clinical applications. The imaging contrast depends on the microwave-absorption coefficient of the endogenous imaged tissue and the injected MTAI contrast agents. With systemically introduced functional nanoparticles, MTAI contrast and sensitivity can be further improved, and enables visualization of biological processes in vivo. In recent years, functional nanoparticles for MTAI have been developed to improve the performance and application range of MTAI in biomedical applications. This paper reviews the recent progress of functional nanoparticles for MTAI and their biomedical applications. The challenges and future directions of microwave thermoacoustic imaging with functional nanoparticles in the field of translational medicine are discussed. [ABSTRACT FROM AUTHOR]

The potential of coordination polymers (CPs) as a host of integrating multiple guest species to construct a fluorescence resonance energy transfer (FRET) nanoprobe was demonstrated. The ZnCPs built from zinc(II) and adenine was employed as a model of CPs to integrate carbon dot (CD) and phenol red (PR) for producing the FRET nanoprobe (CD/PR@ZnCPs). Benefiting from the confinement effect of ZnCPs, the integrated CD and PR can be brought in close proximity to favor the occurrence of FRET process from CD to PR, which leads to the quenching of CD fluorescence. However, the FRET process was disrupted upon the red-shift of PR absorption from 428 to 562 nm in alkaline medium, and consequently switches on the fluorescence of CD/PR@ZnCPs. Based on this finding, by utilizing urease to hydrolyze urea and mediate medium pH, a turn-on fluorescent method was established for the detection of urease activity. This fluorescent method has a linear response that covers 5 to 150 U/L urease with a detection limit of 0.74 U/L and exhibits an excellent selectivity over other enzymes. The successful determination of urease in saliva samples demonstrates the applicability of the fluorescent nanoprobe in complex biological matrix. [ABSTRACT FROM AUTHOR]

Fluorescent sensing of formaldehyde (FA) in the environment is of great significance for human health. However, the development of ratiometric fluorescent probes for ultrasensitive FA detection is challenging due to the lack of suitable strategies. In this study, we demonstrate that ratiometric FA nanoprobes can be facile constructed by integrating two simultaneously excitable fluorophores into a polymer matrix. Using this strategy, we developed a ratiometric fluorescent nanoprobe (Nano‐FAP‐1) for the highly sensitive detection of FA in environmental samples by incorporating a 4‐hydrazino‐1,8‐naphthalimide derivative (Na‐FA) as the receptor and 7‐diethylaminocoumarin‐3‐carboxyl ethyl acetate (Cou‐1) as the reference into a Pluronic F‐127 matrix. The probe achieved a highly sensitive and selective response to low concentrations of FA, with a response time of fewer than 5 s and a detection limit of 0.407 μM. It is worth noting that the probe can be used for the determination of FA in wood and food samples, demonstrating its potential application in the field of toxic gas monitoring and environmental protection. [ABSTRACT FROM AUTHOR]

Background: Mesothelin (MSLN) has been implicated in cancer migration, invasion, and prognosis, making it a potential tumor marker. However, the precise role of MSLN in the migration and invasion of malignant pleural mesothelioma (MPM) remains elusive, and effective noninvasive methods for assessing MSLN status are currently lacking. In this study, we focused on MSLN expression and elucidated the underlying mechanisms by which MSLN regulates migration and invasion in MPM. Building upon this knowledge, we developed an MRI nanoprobe that targets MSLN to assess its status in vitro and in vivo by comparing T2 signal intensity and T2 values on magnetic resonance imaging examinations. This nanoprobe combines the anatomical information obtained from MRI with biological information obtained from MSLN for comprehensive evaluation of MPM. Results: Notably, we observed that MSLN expression in the epithelial type of MPM was higher and increased continuously with tumor growth than that in other types. In addition, MSLN upregulation promoted N-cadherin, matrix metalloproteinase-7, and MMP9 expression and resulted in higher migration/invasion ability and shorter survival. We synthesized MSLN-targeted nanoprobes (Fe3O4@SiO2-PEG-MSLN, FSPM) to assess MSLN expression by comparing the T2 signal intensity and T2 value of different cell lines and mice after 14, 28, and 42 days of modeling. Remarkably, MSLN-targeted nanoprobes demonstrated excellent targeting capabilities. In vitro studies revealed a pronounced reduction in T2 signal intensity and T2 values of the epithelial type as the probe concentration increased. In addition, in vivo experiments demonstrated a gradual decline in these parameters over time, particularly in the epithelial type as compared to the biphasic type, corresponding to the dynamic expression patterns of MSLN during different growth stages. Conclusion: Our comprehensive research succeeded in confirming the regulatory mechanisms by which MSLN influences migration and invasion. Moreover, we introduced a promising method for monitoring MSLN expression that may help in facilitating the early detection, histological subtype identification, and assessment of migration, invasion, and prognosis in MPM. [ABSTRACT FROM AUTHOR]