Holistic Prediction of AuNP Aggregation in Diverse Aqueous Suspensions Based on Machine Vision and Dark-Field Scattering Imaging.

The localized surface-plasmon resonance of the AuNP in aqueous media is extremely sensitive to environmental changes. By measuring the signal of plasmon scattering light, the dark-field microscopic (DFM) imaging technique has been used to monitor the aggregation of AuNPs, which has attracted great attention because of its simplicity, low cost, high sensitivity, and universal applicability. However, it is still challenging to interpret DFM images of AuNP aggregation due to the heterogeneous characteristics of the isolated and discontinuous color distribution. Herein, we introduce machine vision algorithms for the training of DFM images of AuNPs in different saline aqueous media. A visual deep learning framework based on AlexNet is constructed for studying the aggregation patterns of AuNPs in aqueous suspensions, which allows for rapid and accurate identification of the aggregation extent of AuNPs, with a prediction accuracy higher than 0.96. With the aid of machine learning analysis, we further demonstrate the prediction ability of various aggregation phenomena induced by both cation species and the concentration of the external saline solution. Our results suggest the great potential of machine vision frameworks in the accurate recognition of subtle pattern changes in DFM images, which can help researchers build predictive analytics based on DFM imaging data.

Amperometric Identification of Single Exosomes and Their Dopamine Contents Secreted by Living Cells.

Dopamine (DA) is an important neurotransmitter, which not only participates in the regulation of neural processes but also plays critical roles in tumor progression and immunity. However, direct identification of DA-containing exosomes, as well as quantification of DA in single vesicles, is still challenging. Here, we report a nanopipette-assisted method to detect single exosomes and their dopamine contents via amperometric measurement. The resistive-pulse current measured can simultaneously provide accurate information of vesicle translocation and DA contents in single exosomes. Accordingly, DA-containing exosomes secreted from HeLa and PC12 cells under different treatment modes successfully detected the DA encapsulation efficiency and the amount of exosome secretion that distinguish between cell types. Furthermore, a custom machine learning model was constructed to classify the exosome signals from different sources, with an accuracy of more than 99%. Our strategy offers a useful tool for investigating single exosomes and their DA contents, which facilitates the analysis of DA-containing exosomes derived from other untreated or stimulated cells and may open up a new insight to the research of DA biology.

Specially Resolved Single Living Cell Perfusion and Targeted Fluorescence Labeling Based on Nanopipettes.

Targeted delivery and labeling of single living cells in heterogeneous cell populations are of great importance to understand the molecular biology and physiological functions of individual cells. However, it remains challenging to perfuse fluorescence markers into single living cells with high spatial and temporal resolution without interfering neighboring cells. Here, we report a single cell perfusion and fluorescence labeling strategy based on nanoscale glass nanopipettes. With the nanoscale tip hole of 100 nm, the use of nanopipettes allows special perfusion and high-resolution fluorescence labeling of different subcellular regions in single cells of interest. The dynamic of various fluorescent probes has been studied to exemplify the feasibility of nanopipette-dependent targeted delivery. According to experimental results, the cytoplasm labeling of Sulfo-Cyanine5 and fluorescein isothiocyanate is mainly based on the Brownian movement due to the dyes themselves and does not have a targeting ability, while the nucleus labeling of 4',6-diamidino-2-phenylindole (DAPI) is originated from the adsorption between DAPI and DNA in the nucleus. From the finite element simulation, the precise manipulation of intracellular delivery is realized by controlling the electro-osmotic flow inside the nanopipettes, and the different delivery modes between nontargeting dyes and nucleus-targeting dyes were compared, showcasing the valuable ability of nanopipette-based method for the analysis of specially defined subcellular regions and the potential applications for single cell surgery, subcellular manipulation, and gene delivery.

Dynamic Visualization of Endoplasmic Reticulum Stress in Living Cells via a Two-Stage Cascade Recognition Process.

The endoplasmic reticulum (ER) is crucial for the regulation of multiple cellular processes, such as cellular responses to stress and protein synthesis, folding, and posttranslational modification. Nevertheless, monitoring ER physiological activity remains challenging due to the lack of powerful detection methods. Herein, we built a two-stage cascade recognition process to achieve dynamic visualization of ER stress in living cells based on a fluorescent carbon dot (CD) probe, which is synthesized by a facile one-pot hydrothermal method without additional modification. The fluorescent CD probe enables two-stage cascade ER recognition by first accumulating in the ER as the positively charged and lipophilic surface of the CD probe allows its fast crossing of multiple membrane barriers. Next, the CD probe can specifically anchor on the ER membrane via recognition between boronic acids and o-dihydroxy groups of mannose in the ER lumen. The two-stage cascade recognition process significantly increases the ER affinity of the CD probe, thus allowing the following evaluation of ER stress by tracking autophagy-induced mannose transfer from the ER to the cytoplasm. Thus, the boronic acid-functionalized cationic CD probe represents an attractive tool for targeted ER imaging and dynamic tracking of ER stress in living cells.

Deep Learning-Based Spectral Extraction for Improving the Performance of Surface-Enhanced Raman Spectroscopy Analysis on Multiplexed Identification and Quantitation.

Surface-enhanced Raman spectroscopy (SERS) has been recognized as a promising analytical technique for its capability of providing molecular fingerprint information and avoiding interference of water. Nevertheless, direct SERS detection of complicated samples without pretreatment to achieve the high-efficiency identification and quantitation in a multiplexed way is still a challenge. In this study, a novel spectral extraction neural network (SENN) model was proposed for synchronous SERS detection of each component in mixed solutions using a demonstration sample containing diquat dibromide (DDM), methyl viologen dichloride (MVD), and tetramethylthiuram disulfide (TMTD). A SERS spectra dataset including 3600 spectra of DDM, MVD, TMTD, and their mixtures was first constructed to train the SENN model. After the training step, the cosine similarity of the SENN model can achieve 0.999, 0.997, and 0.994 for DDM, MVD, and TMTD, respectively, which means that the spectra extracted from the mixture are highly consistent with those collected by the SERS experiment of the corresponding pure samples. Furthermore, a convolutional neural network model for quantitative analysis is combined with the SENN, which can simultaneously and rapidly realize the qualitative and quantitative SERS analysis of mixture solutions with lower than 8.8% relative standard deviation. The result demonstrates that the proposed strategy has great potential in improving SERS analysis in environmental monitoring, food safety, and so on.

Nanopipette-Based Nanosensor for Label-Free Electrochemical Monitoring of Cell Membrane Rupture under H2O2 Treatment.

H2O2 is an essential signaling molecule in living cells that can cause direct damage to lipids, proteins, and DNA, resulting in cell membrane rupture. However, current studies mostly focus on probe-based sensing of intracellular H2O2, and these methods usually require sophisticated probe synthesis and instruments. In particular, local H2O2 treatment induces cell membrane rupture, but the level of cell membrane destruction is unknown because the mechanical properties of the cell membrane are difficult to accurately determine. Therefore, highly sensitive and label-free methods are required to measure and reflect mechanical changes in the cell membrane. Here, using an ultrasmall quartz nanopipette with a tip diameter less than 90 nm as a nanosensor, label-free and noninvasive electrochemical single-cell measurement is achieved for real-time monitoring of cell membrane rupture under H2O2 treatment. By spatially controlling the nanopipette tip to precisely approach a specific location on the membrane of a single living cell, stable cyclic membrane oscillations are observed under a constant direct current voltage. Specifically, upon nanopipette advancement, the mechanical status of the cell membrane can be sensibly displayed by continuous current versus time traces. The electrical signals are collected and processed, ultimately revealing the mechanical properties of the cell membrane and the degree of cell apoptosis. This nanopipette-based nanosensor paves the way for developing a facile, label-free, and noninvasive strategy to assay the mechanical properties of the cell membrane during external stimulation at the single-cell level.

Development and validation of a risk assessment nomogram for venous thromboembolism associated with hospitalized postoperative Chinese breast cancer patients.

AIM: The purpose of this study was to develop and validate an individualized nomogram to predict venous thromboembolism (VTE) risk in hospitalized postoperative breast cancer patients. DESIGN: A single-central retrospective and non-interventional trial. METHODS: For model development, we used data from 4,755 breast cancer patients between 1 November 2016-30 June 2018 (3,310 patients in the development group and 1,445 in the validation group). Overall, 216 patients developed VTE (150 in development group and 66 in validation group). The model was validated by receiver operating characteristic curves and the calibration plot. The clinical utility of the model was determined through decision curve analysis. RESULTS: The individualized nomogram consisted of six clinical factors: age, body mass index, number of cardiovascular comorbidities, neoadjuvant chemotherapy, surgical treatment, hospital length of stay and two pre-operative biomarkers of Homocysteine and D-dimer. The model at the 3.9% optimal cut-off had the area under the curve of 0.854 (95% CI, 0.824-0.884) and 0.805 (95% CI, 0.740-0.870) in the development and validation groups. A p = 0.570 of the calibration test showed that the model was well-calibrated. The net benefit of the model was better between threshold probabilities of 5%-30% in decision curve analysis. CONCLUSION: The nomogram of VTE risk assessment, is applicable to hospitalized postoperative breast cancer patients. However, multi-central prospective studies are needed to improve and validate the model. Effectiveness and safety of thromboprophylaxis in high-risk patients are needed to demonstrate in interventional trials. IMPACT: This nomogram can be used in clinical to inform practice of physicians and nurses to predict the VTE probability and maybe direct personalized decision making for thromboprophylaxis in hospitalized postoperative breast cancer patients.

Probing the Membrane Vibration of Single Living Cells by Using Nanopipettes.

The vibration of a cell membrane plays a key role in the regulation of cell shape and the behavior of cells. However, most existing approaches for the measurement of cell vibration require either exogenous modification or sophisticated techniques, and the main challenge lies in developing methods that can monitor membrane vibration of living cells directly. Herein, a noninvasive strategy based on ultrasmall quartz nanopipettes is introduced. With a tip size of less than 100 nm, nanopipettes can be spatially controlled for precision targeting of a specific location on the membrane of single living cells. Surprisingly, by employing a constant voltage, stable cyclic oscillations are observed from the continuous current versus time traces. The time-domain current can be decomposed into two basic waves: the high-frequency one indicates the local membrane vibration driven by the electro-osmotic flow from the nanopipette, whereas the low-frequency one indicates the natural frequency of the whole cell. This provides a simple but reliable method to test local and global membrane vibration of single living cells simultaneously with little damage, which provides a tool for the quantification of drugs, disease, or mutations of the cell structure.

A polydopamine-based biomimetic multifunctional nanoplatform for multilayer imaging of cancer biomarkers carried by extracellular vesicles.

Cancer-derived extracellular vesicles (EVs) have attracted considerable attention for clinical diagnosis. However, a limiting factor in current EV assays is the ability to detect various EV cancer biomarkers expressed at different locations. Here, we report a biomimetic multifunctional nanoplatform for multilayer imaging of cancer biomarkers from the EV surface to the interior without complex pretreatment. Constructed from polydopamine-wrapped gold nanoparticles modified with multiple functional molecules, this nanoplatform can capture EVs from complex samples and target different EV cancer biomarkers for imaging analysis at the single-vesicle level. Combined with 96-well plates, this assay can distinguish cancer cell-derived EVs from normal ones in a high-throughput manner. Using serum samples, EVs from hepatocellular carcinoma (HCC) patients can be distinguished from healthy controls. This convenient workflow represents a promising tool for EV-based cancer diagnosis.

MiR-24 Protects Cardiomyocytes Against Hypoxia/Reoxygenation-Induced Injury Through Regulating Mitogen-Activated Protein Kinase 14.

This study aimed to explore the function of miR-24 in hypoxia/reoxygenation (H/R) -induced cardiomyocyte injury.We constructed a cardiomyocyte model of H/R using the primary cardiomyocytes isolated from Sprague-Dawley rats. To explore the role of miR-24, cells were transfected with a miR-24 mimic or miR-24 inhibitor. The RNA expression levels of miR-24 and Mapk14 were determined using qRT-PCR. The proliferation and apoptosis of cells were determined using a CCK8 assay and a flow cytometer. The TargetScan website was used to predict the targets of miR-24. A dual-luciferase reporter gene assay was conducted to verify whether Mapk14 is indeed a target of miR-24. A Western blot was applied for protein detection.H/R exposure decreased the expression of miR-24 in rat cardiomyocytes. Transfection of the miR-24 mimic into cardiomyocytes reduced H/R-induced injury as evidenced by an increase in proliferation and a decrease in the apoptotic rate. By contrast, transfection of the miR-24 inhibitor aggravated H/R-induced injury. The expression of Bcl-2 was increased while the levels of Bax and Active-caspase 3 were reduced in the H/R+miR-24 mimic group compared to those in the H/R group. H/R+miR-24 inhibitor group showed the opposite results. Mapk14 was identified as a target of miR-24. The mRNA level of Mapk14 and its protein (p38 MAPK) level were negatively affected by miR-24. Furthermore, we discovered that depletion of Mapk14 reduced the promoting effect of the miR-24 inhibitor on cell apoptosis.Overall, our results illustrated that miR-24 could attenuate H/R-induced injury partly by regulating Mapk14.

Clinical efficacy of low-dose rituximab on hematological abnormalities in patients with connective tissue disease
.

OBJECTIVE: To evaluate the efficacy and safety of low-dose rituximab in the treatment of hematologic abnormalities in patients with connective tissue disease. MATERIALS AND METHODS: A total of 13 patients with connective tissue disease who did not respond to prednisolone and multiple immunosuppressive agents, or their disease recurred after treatment, were given 100 mg of rituximab only combined with prednisolone once a week for 4 weeks. Then, the therapeutic effects and adverse reactions were respectively observed in the 13 patients. RESULTS: Rituximab showed good and rapid efficacy in the treatment of refractory thrombocytopenia and autoimmune hemolytic anemia caused by systemic lupus erythematosus, Sjögren's syndrome, and mixed connective tissue disease. Only 1 patient had urinary tract infection. During 24-month follow-up, disease recurred in 7 patients who still responded to azathioprine/Tripterygium wilfordii. CONCLUSION: Low-dose rituximab has good efficacy and safety in the treatment of hematologic abnormalities in patients with connective tissue disease.

[MiR-155 Inhibits the Expression of MMPs in HK2 Cells by Targeting KLF4].

OBJECTIVES: To determine whether miR -155 inhibits the expression of matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9) in HK2 cells by targeting Kruppel-like factor 4 (KLF4). METHODS: MiR -155-mimic, miR -155-NC empty plasmid, and culture medium were transfected into renal tubular epithelial cells, respectively. Six hours later, the expression of miR -155 was detected by real time-PCR; the expressions of MMP-2, MMP-9 and KLF4 were detected by Western blot; and the activity of MMP-2 and MMP-9 in the cells was detected by gelatin zymography. Because KLF4 was predicted as the target gene of miR -155 by bioinformatics. The miR-155 overexpressed HK2 cells were transfected with KLF4 overexpression plasmid or empty plasmid. Six hours later, the expressions of MMP-2, MMP-9 and KLF4, and the activity of MMP-2 and MMP-9 were measured again. Finally, cells containing luciferase plasmids with KLF4-3!d-UTR wild type (WT) or mutant (MUT) sequence were constructed and transfected with miR -155-mimic or empty plasmid. Luciferase assay was used to confirm whether KLF4 -3!d-UTR was the binding site in targeting miR -155#. RESULTS: Compared with the cells transfected with empty plasmid, the expression of miR -155 was up-regulated and the expressions of MMP-2, MMP-9 and KLF4 were down-regulated in the cells transfected with miR -155-mimic. Compared with the cells transfected with miR -155 mimic or miR -155 mimic+empty plasmid, the expressions of MMP-2, MMP-9 and KLF4 were up-regulated in the KLF4+miR -155 transfected cells. Luciferase assays confirmed that miR -155 binds to KLF4 , and KLF4 -3!d-UTR is the target gene of miR -155. CONCLUSION: MiR-155 inhibits the expressions of MMP-2 and MMP-9 in HK2 cells by targeting KLF4 -3!d-UTR.

Analysis of vibrational dynamics in cell-substrate interactions using nanopipette electrochemical sensors.

Cell-substrate interaction plays a critical role in determining the mechanical status of living cell membrane. Changes of substrate surface properties can significantly alter the cell mechanical microenvironment, leading to mechanical changes of cell membrane. However, it is still difficult to accurately quantify the influence of the substrate surface properties on the mechanical status of living cell membrane without damage. This study addresses the challenge by using an electrochemical sensor made from an ultrasmall quartz nanopipette. With the tip diameter less than 100 nm, the nanopipette-based sensor achieves highly sensitive, noninvasive and label-free monitoring of the mechanical status of single living cells by collecting stable cyclic membrane oscillatory signals from continuous current versus time traces. The electrochemical signals collected from PC12 cells cultured on three different substrates (bare ITO (indium tin oxides) glass, hydroxyl modified ITO glass, amino modified ITO glass) indicate that the microenvironment more favorable for cell adhesion can increase the membrane stiffness. This work provides a label-free electrochemical approach to accurately quantify the mechanical status of single living cells in real-time, which may help to better understand the relationship between the cell membrane and the extra cellular matrix.

Natural compound library screening to identify berberine as a treatment for rheumatoid arthritis.

OBJECTIVE: Fibroblast-like synoviocytes (FLS) play a critical role on the exacerbation and deterioration of rheumatoid arthritis (RA). Aberrant activation of FLS pyroptosis signaling is responsible for the hyperplasia of synovium and destruction of cartilage of RA. This study investigated the screened traditional Chinese medicine berberine (BBR), an active alkaloid extracted from the Coptis chinensis plant, that regulates the pyroptosis of FLS and secretion of inflammatory factors in rheumatoid arthritis. METHODS: First, BBR was screened using a high-throughput drug screening strategy, and its inhibitory effect on RA-FLS was verified by in vivo and in vitro experiments. Second, BBR was intraperitoneally administrated into the collagen-induced arthritis rat model, and the clinical scores, arthritis index, and joint HE staining were evaluated. Third, synovial tissues of CIA mice were collected, and the expression of NLRP3, cleaved-caspase-1, GSDMD-N, Mst1, and YAP was detected by Western blot. RESULTS: The administration of BBR dramatically alleviated the severity of collagen-induced arthritis rat model with a decreased clinical score and inflammation reduction. In addition, BBR intervention significantly attenuates several pro-inflammatory cytokines (interleukin-1ß, interleukin-6, interleukin-17, and interleukin-18). Moreover, BBR can reduce the pyroptosis response (caspase-1, NLR family pyrin domain containing 3, and gasdermin D) of the RA-FLS in vitro, activating the Hippo signaling pathway (Mammalian sterile 20-like kinase 1, yes-associated protein, and transcriptional enhanced associate domains) so as to inhibit the pro-inflammatory effect of RA-FLS. CONCLUSION: These results support the role of BBR in RA and may have therapeutic implications by directly repressing the activation, migration of RA-FLS, which contributing to the attenuation of the progress of CIA. Therefore, targeting PU.1 might be a potential therapeutic approach for RA. Besides, BBR inhibited RA-FLS pyroptosis by downregulating of NLRP3 inflammasomes (NLRP3, caspase-1) and eased the pro-inflammatory activities via activating the Hippo signaling pathway, thereby improving the symptom of CIA.

[Treatment of diabetic foot by clearing heat, detoxification, activating blood, and dredging collaterals method].

OBJECTIVE: To study the mechanism of treating diabetic foot by clearing heat, detoxification, activating blood, and dredging collaterals method. METHODS: Sixty diabetic foot patients were randomly assigned to the treatment group and the control group, 30 cases in each group. On the basis of the same routine treatment, patients in the treatment group were treated by Qingjie Tongluo Recipe (QTR) plus external washing of Chinese herbs plus external dressing by herbs with removing necrosis and promoting granulation actions, while those in the control group were treated with routine aseptic external dressing. Three months was taken as one therapeutic course. The wound area and basic fibroblast growth factor (bFGF) were detected before and after treatment. The content of vascular endothelial growth factor (VEGF), the peripheral vascular and nerve functions were also measured. The therapeutic effects were also observed. RESULTS: After treatment, in the treatment group,15 patients were cured, 12 markedly effective, 2 effective, 1 ineffective, the cure rate was 50.0% and the total effective rate was 96.7%, while in the control group, 9 cases were cured, 6 markedly effective, 8 effective, 7 ineffective, the cure rate was 30.0% and the total effective rate was 76.7%. The total effective rate was better in the treatment group than in the control group (P <0. 01). The contents of bFGF and VEGF were significantly higher in the two groups after treatment (P <0.01). Besides, better results were obtained in the treatment group (P < 0.01). The blood flow speed of the dorsalis pedis artery, the inner diameter of the dorsalis pedis artery, and the common peroneal nerve conduction velocity were somewhat improved (P <0.05, P <0.01). Besides, better results were obtained in the treatment group (P <0.01). CONCLUSIONS: QTR combined external washing plus external dressing by herbs with removing necrosis and promoting granulation actions could promote the healing of diabetic foot induced ulcers, improve the vascular and nerve functions. Its efficacy was superior to that of the control group.

The Modification and Applications of Nanopipettes in Electrochemical Analysis.

Nanopipette, which is fabricated by glasses and possesses a nanoscale pore in the tip, has been proven to be immensely useful in electrochemical analysis. Numerous nanopipette-based sensors have emerged with improved sensitivity, selectivity, ease of use, and miniaturization. In this minireview, we provide an overview of the recent developments of nanopipette-based electrochemical sensors based on different types of nanopipettes, including single-nanopipettes, self-referenced nanopipettes, dual-nanopipettes, and double-barrel nanopipettes. Several important modification materials for nanopipette functionalization are highlighted, such as conductive materials, macromolecular materials, and functional molecules. These materials can improve the sensing performance and targeting specificities of nanopipettes. We also discuss examples of related applications and the future development of nanopipette-based strategies.

Peroxiredoxin-6 Released by Astrocytes Contributes to Neuroapoptosis During Ischemia.

Peroxiredoxin-6 (PRDX6), a member of the peroxiredoxin family, has progressively emerged as a possible therapeutic target for a variety of brain diseases, particularly Alzheimer's disease and ischemic stroke. However, the role of PRDX6 in neurons under ischemic conditions has remained elusive. Here, we found that astrocytes could release PRDX6 extracellularly after OGD/R, and that PRDX6 release actually worsened neuroapoptosis under OGD/R. We discovered a unique PRDX6/RAGE/JNK signaling pathway that contributes to the effect of neuroapoptosis. We applied a specific inhibitor of the RAGE signaling pathway in a mouse MCAO model and observed significant alterations in animal behavior. Considered together, our findings show the crucial role of the astrocyte-released PRDX6 in the process of neuroapoptosis caused by OGD/R, and could provide novel insights for investigating the molecular mechanism of protecting brain function from ischemia-reperfusion injury.

Palladium(II)-Catalyzed Intramolecular [2 + 2 + 2] Annulation of Indolyl 1,3-Diynes: Construction of Azepino-Fused Carbazoles.

A novel palladium(II)-catalyzed intramolecular [2 + 2 + 2] annulation of indolyl 1,3-diynes is described in this contribution. A variety of azepino-fused carbazoles are obtained in moderate to excellent yields. The key to the success of this transformation is the use of a carboxylic acid as an additive. This protocol features broad functional group tolerances, easy handling in air, and 100% atom economy. Furthermore, scale-up reactions, late-stage derivatizations, and photophysical property investigations highlight the potential synthetic utility of this methodology.

Engineered Extracellular Vesicle-Encapsuled Nanoreactors for Effective Targeting and Cascade Killing of Cancer Cells.

Nanomaterials have presented great potential for cancer therapy. However, their therapeutic efficacy is not always satisfied because of inefficient biocompatibility and targeting efficacy. Here, we report engineered extracellular vesicle (EV)-encapsuled nanoreactors for the targeting and killing of cancer cells. EVs are extracted from engineered cancer cells with surface N-glycans cut and intracellular microRNA-21 (miR-21) silenced to generate cancer-targeting membranes for the following coating of gold-polydopamine (PDA) core-shell nanoparticles. The encapsuled nanoparticles are decorated with doxorubicin (Dox), glucose oxidase (GOx), and miR-21-indicative DNA tags. Once endocytosed, the acidic pH, together with the photothermal effect of the PDA shell, can promote the release of Dox and GOx-catalyzed H2O2 generation/glucose consumption, while the DNA tags allow enhanced fluorescence imaging of miR-21 to indicate the targeting effect. The coadministration of EV-assisted delivery and cascade treatment represents a promising strategy for combination therapy.

Spatiotemporal Controlled Formation of Synthetic Nanoreactors in Single Living Cells.

Cellular compartments provide confined environments for spatiotemporal control of biological processes and enzymatic reactions. To mimic such compartmentalization of eukaryotic cells, we report an efficient and general platform to precisely control the formation of artificial nanoreactors in single living cells. We introduce an electroosmotic controlled strategy for the synthesis of ZIF-8 at the nanoscale liquid-liquid interface around the tip of a nanopipet, whereby the formed ZIF-8 nanoparticles are driven into a single living cell by the electroosmotic flow. The porous ZIF-8 nanoparticles, as synthetic nanoreactors, are not only able to harvest fluorescent molecules from peripheral cytoplasm but also perform the subsequent photocatalytic degradation, mimicking compartmentalized chemical reactions in eukaryotic cells. Our strategy provides a useful tool for spatiotemporal controlled synthesis of artificial nanoreactors with on-demand functions in single living cells with versatile applications in chemical biology.