Sulforaphane and bladder cancer: a potential novel antitumor compound.

Bladder cancer (BC) is a common form of urinary tract tumor, and its incidence is increasing annually. Unfortunately, an increasing number of newly diagnosed BC patients are found to have advanced or metastatic BC. Although current treatment options for BC are diverse and standardized, it is still challenging to achieve ideal curative results. However, Sulforaphane, an isothiocyanate present in cruciferous plants, has emerged as a promising anticancer agent that has shown significant efficacy against various cancers, including bladder cancer. Recent studies have demonstrated that Sulforaphane not only induces apoptosis and cell cycle arrest in BC cells, but also inhibits the growth, invasion, and metastasis of BC cells. Additionally, it can inhibit BC gluconeogenesis and demonstrate definite effects when combined with chemotherapeutic drugs/carcinogens. Sulforaphane has also been found to exert anticancer activity and inhibit bladder cancer stem cells by mediating multiple pathways in BC, including phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR), mitogen-activated protein kinase (MAPK), nuclear factor kappa-B (NF-κB), nuclear factor (erythroid-derived 2)-like 2 (Nrf2), zonula occludens-1 (ZO-1)/beta-catenin (ß-Catenin), miR-124/cytokines interleukin-6 receptor (IL-6R)/transcription 3 (STAT3). This article provides a comprehensive review of the current evidence and molecular mechanisms of Sulforaphane against BC. Furthermore, we explore the effects of Sulforaphane on potential risk factors for BC, such as bladder outlet obstruction, and investigate the possible targets of Sulforaphane against BC using network pharmacological analysis. This review is expected to provide a new theoretical basis for future research and the development of new drugs to treat BC.

In Situ Investigation of Intercellular Signal Transduction Based on Detection of Extracellular pH and ROS by Scanning Electrochemical Microscopy.

Intercellular signal transduction plays an important role in the regulation of biological activities. Herein, a Transwell chamber-based two-layer device combined with scanning electrochemical microscopy (SECM) technology has been proposed for in situ investigation of intercellular signal transduction. The cells in the device were cultured on two layers: the lower layer was for signaling cells, and the upper layer was for signal-receiving cells. The extracellular pH (pHe) and ROS (reactive oxygen species, ROSe) were in situ monitored by SECM potentiometric mode and SECM-MPSW (multipotential step waveform), respectively. When the signaling cells, including MCF-7, HeLa, and HFF cells, were electrically stimulated, the ROS release of the signal-receiving cells was promoted. By detecting the pH at the cell surface, it was found that more H+ generated by the signaling cells and two cell layers at a shorter distance could both cause the signal-receiving cells to release more ROS, revealing that H+ is one of the signaling molecules of intercellular communication. This SECM-based in situ monitoring strategy provides an effective way to investigate intercellular signal transduction and explore the corresponding mechanism.

A multi-calibration potentiometric sensing array based on diboronic acid-PtAu/CNTs nanozyme for home monitoring of urine glucose.

All-solid-state potentiometric sensors that are easily miniaturized and arrayed are widely used in home diagnostics. However, changes in sample matrix compositions tend to affect the basic potential of the potentiometric sensor, and pH of sample could change the response slope, thus affecting the detection reliability. This study takes the detection of glucose in urine as a model to increase the reliability of potentiometric sensors in home detection. PtAu/CNTs nanozyme modified by diboronic acid has been designed, showing better catalytic selectivity for glucose by experiments and theoretical calculations. Moreover, glucose electrode group in a multi-calibration glucose potentiometric sensing array can realize the basic potential calibration of sensing channel by the calibration channel. Meanwhile, the pH electrode group can not only measure the urine pH, but also calibrate the response slope of the glucose electrode group, thus improving the reliability of home detection.

A Multicalibration Urea Potentiometric Sensing Array Based on Au@urease Nanoparticles and Its Application in Home Detection.

Home potentiometric sensing devices can real-time monitor personal health status and are widely used in the prevention and management of related diseases. However, variations in the composition and the pH of the sample matrix tend to change the basic potential and response slope of some potentiometric sensors, thus affecting detection reliability. Therefore, this work uses the detection of urea in urine as a model to improve reliability of the potentiometric sensor in home detection. Au@urease nanoparticles were synthesized as the sensing material to improve the stability of the urease-based potentiometric sensor. Meanwhile, a multicalibrated urea potential (MCUP) sensing array was designed, which consists of a urea electrode group, a pH electrode group, and a reference channel. The urea electrode group and the pH electrode group contain respectively a sensing channel and a calibration channel. The basic potential of sensing channels can be calibrated through the corresponding calibration channels. Moreover, the pH electrode group can not only measure the pH values of the samples but also calibrate the response slope of the urea electrode group through the calibration coefficient, thus improving the reliability of home detection. Consequently, the potentiometric sensing array based on the enzyme reaction can be applied in body fluids with a wide pH range.

Biosensing bacterial 16S rDNA by microchip electrophoresis combined with a CRISPR system based on real-time crRNA/Cas12a formation.

The accurate, simple and sensitive detection of bacterial infections at the early stage is highly valuable in preventing the spread of disease. Recently, CRISPR-Cas12a enzyme-derived nucleic acid detection methods have emerged along with the discovery of the indiscriminate single-stranded DNA (ssDNA) cleavage activity of Cas12a. These nucleic acid detection methods are made effective and sensitive by combining them with isothermal amplification technologies. However, most of the proposed CRISPR-Cas12a strategies involve Cas-crRNA complexes in the preassembled mode, which result in inevitable nonspecific background signals. Besides, the signal ssDNA used in these strategies needs tedious pre-labeling of the signal molecules. Herein, a post-assembly CRISPR-Cas12a method has been proposed based on target-induced transcription amplification and real-time crRNA generation for bacterial 16S rDNA biosensing. This strategy is label-free through the combination of microchip electrophoresis (MCE) detection. In addition, this method eliminates the need for a protospacer adjacent motif (PAM) on the target sequences, and has the potential to be an effective and simple method for nucleic acid detection and infectious disease diagnosis.

In Situ Monitoring of Extracellular K+ Using the Potentiometric Mode of Scanning Electrochemical Microscopy with a Carbon-Based Potassium Ion-Selective Tip.

The expression of potassium channels can be related to the occurrence and development of tumors. Their change would affect K+ outflow. Thus, in situ monitoring of extracellular K+ shows a great significance. Herein, the dual-functional K+ ion-selective electrode as the scanning electrochemical microscopy (SECM) tip (K+-ISE SECM tip) has been developed for in situ monitoring of the extracellular K+. Based on multi-wall carbon nanotubes as a transduction layer, the K+-ISE SECM tip realizes both the plotting of approach curves to position the tip for in situ detection and the recording of potential responses. It shows a near Nernstian response, good selectivity, and excellent stability. Based on these characteristics, it was used to in situ monitor K+ concentrations ([K+]o) of three breast cancer cell lines (MCF-7, MDA-MB-231, and SK-BR-3 cells) at 3 µm above the cell, and [K+]o of MDA-MB-231 cells show the highest value, followed by MCF-7 cells and SK-BR-3 cells. K+ outflow induced by electrical stimulation or pH changes of the culture environment (Δ[K+]o) was further determined, and the possible mechanism of K+ outflow was investigated with 4-aminopyridin (4-AP). MCF-7 cells present the largest value of Δ[K+]o, followed by MDA-MB-231 cells and SK-BR-3 cells at all the stimulation potentials, and pH 6.50 shows the greatest impact on K+ outflow of the three cell lines. The pretreatment of 4-AP changed K+ outflow, probably due to the regulation of voltage-gated channels. These findings provide insight into a deep understanding of the microenvironment influence on K+ outflow, thereby reflecting the possible mechanism of potassium channels.

In situ monitoring of the effect of Cu2+ on the membrane permeability of a single living cell with a dual-electrode tip of a scanning electrochemical microscope.

Here, an Au-Cu dual-electrode tip was designed to monitor the effect of Cu2+ on the membrane permeability of a single living cell in situ using scanning electrochemical microscopy. The probe approach curves (PACs) were obtained using potassium ferricyanide as a redox mediator. Meanwhile, according to the simulation, theoretical PACs could be acquired. Thus, the cell membrane permeability coefficient (Pm) values were obtained by overlapping the experimental PACs with the theoretical values. Cu2+ was directly generated by electrolyzing the Cu electrode of the dual-electrode tip to investigate its effect on the cell membrane permeability in situ. This work has potential value to improve the understanding of the mechanism of acute heavy metal damage on the cell membrane and will also help clarify the role of heavy metal ions in physiological or pathological processes.

A ratiometric electrochemical biosensor for glycated albumin detection based on enhanced nanozyme catalysis of cuprous oxide-modified reduced graphene oxide nanocomposites.

Nanozymes have enzyme-like characteristics and nanozyme-based electrochemical sensors have been widely studied for biomarker detection. In this work, cuprous oxide-modified reduced graphene oxide (Cu2O-rGO) nanozyme was prepared by simultaneous reduction of copper chloride and graphene oxide. This Cu2O-rGO nanozyme displayed an outstanding electrocatalytic activity to glucose oxidation and was used as the modified material of a glassy carbon electrode to fabricate an electrochemical ratiometric biosensor for glycated albumin (GA) detection. In this ratiometric biosensor, methylene blue-labeled DNA tripods (MB-tDNA) were adsorbed on the Cu2O-rGO/GCE surface to form a bioinspired electrode (MB-tDNA/Cu2O-rGO/GCE), in which the catalytic sites of Cu2O-rGO were covered by MB-tDNA. In the presence of target GA, GA could be identified by the aptamer sequence contained in MB-tDNA, and a MB-tDNA/GA complex was formed and released into the solution, so the reduced current of MB-tDNA was decreased. Simultaneously, the oxidized current of the outer added glucose was increased since more catalytic sites of Cu2O-rGO nanozyme on the substrate electrode surface were exposed. The ratio of the peak currents of glucose oxidation and methylene blue reduction (IGlu/IMB) was used to monitor the GA level and ultimately improve the accuracy of the method. The electrochemical sensor showed a low detection limit of 0.007 µg mL-1 and a wide linear range from 0.02 to 1500 µg mL-1. The proposed sensor was also successfully used to measure the GA expression level in the blood serum of a diabetic mouse model.

A ratiometric electrochemical sensor for the determination of exosomal glycoproteins.

Abnormal glycosylation of exosomal proteins is related to many diseases. However, there is still a lack of convenient and easy methods for the determination of exosomal glycoproteins. In this work, a ratiometric electrochemical sensor based on the recognition of glycoproteins by boronic acid and core-shell nanoparticles of silica-silver (SiO2@Ag) amplified signals was developed for the highly sensitive detection of exosomal glycoproteins. The CD63 aptamer-SiO2-N-(2-((2-aminoethyl)disulfanyl)ethyl) ferrocene carboxamide (FcNHSSNH2) probe was first connected to graphene oxide-cucurbit [7] (GO-CB [7]) modified GCE through host-guest recognition. The CD63 aptamer was employed for the specific capture of exosomes, and the FcNHSSNH2 molecule was used as the internal reference signal of the sensor. The mercaptophenylboronic acid (MPBA) of MPBA-SiO2@Ag probe was used for the identification of exosomes surface glycoproteins. SiO2 nanoparticle has a large specific surface area, which can load a large amount of silver nanoparticles (AgNPs) for electrochemical signal amplification. The results were expressed as the current ratio of AgNPs and FcNHSSNH2. The introduction of the internal reference molecule FcNHSSNH2 could effectively reduce the measurement error caused by the different DNA density of the substrate, and further improve the sensitivity and accuracy of the detection. Under the optimal experimental conditions, this sensor allowed the sensitive detection of exosomal glycoproteins in the range of 4.2 × 102 to 4.2 × 108 particles/µL with a limit of detection (LOD) of 368 particles/µL. Furthermore, the ratiometric electrochemical sensor could be employed for the detection of exosomal glycoproteins in human serum samples, which has a good clinical application prospect.

Home Detection Technique for Na+ and K+ in Urine Using a Self-Calibrated all-Solid-State Ion-Selective Electrode Array Based on Polystyrene-Au Ion-Sensing Nanocomposites.

An all-solid-state ion-selective electrode (ASS-ISE) array that is portable and easily miniaturized can meet the needs of home sensing devices for long-term health monitoring. However, their stability and accuracy are affected by the multistep modification required for ASS-ISE manufacturing and the complex background signal of real samples. In this study, a four-channel ISE array with the integration of a calibration channel has been developed based on polystyrene-Au (PS-Au) ion-sensing nanocomposites (PS-Au ISE array) for the home detection of Na+ and K+. The nanocomposites combine target recognition function and ion-electron transduction function and could be modified on the channel surface by direct drop-casting, thus simplifying the preparation process and then improving the stability. Meanwhile, the integrated calibration channel could automatically deduct complex background signals in real sample analysis and thus improve the accuracy. As a result, the proposed self-calibrated PS-Au ISE array showed a near Nernstian behavior for Na+ and K+ in the range of 1 × 10-2 M-1 × 10-4 M, and the detection limits were 6.8 × 10-5 M and 5.5 × 10-5 M in artificial urine. The linear equations can be obtained according to the slopes and intercepts of Na+ and K+, and thus, the concentration of the target ions can be directly read out by combining this PS-Au ISE array with the smart electronic device. Furthermore, the detection results of Na+ and K+ in human urine agreed well with those obtained by ICP-AES, suggesting that this proposed self-calibrated PS-Au ISE array is very suitable for home smart sensing devices, facilitating the health monitoring.

Theoretical and experimental verification of imaging resolution factors in scanning electrochemical microscopy.

The imaging resolution of scanning electrochemical microscopy (SECM) depends strongly on the tip electrode size and the tip-substrate distance. Herein, etched glass encapsulation was applied to fabricate a gold disk electrode, and the size of the tip electrode was accurately determined from the steady-state limiting current. Referring to the theoretical research carried out by our predecessors, the formula for the imaging resolution was derived, followed by the imaging of gold spots and cells with the prepared microelectrodes of different sizes and with different tip-substrate distances. A depth scan was performed to generate 2D current maps of the gold spot relative to the position of the microelectrode in the x-z plane. Probe approach curves and horizontal sweeps were obtained from one depth scan image by simply extracting vertical and horizontal cross-sectional lines, and further characterized by comparison with simulated curves through modeling of the experimental system. The experimental results were basically consistent with the theory, revealing that the highest imaging resolution can be obtained with the smallest tip electrode when d/a = 1, and when the size of the tip electrode is fixed the smallest tip-substrate distance can give the highest imaging resolution.

Study on Defective T Junction-Mediated Strand Displacement Amplification and Its Application in Microchip Electrophoretic Detection of Longer Bacterial 16S rDNA.

Current strand displacement amplification (SDA)-based nucleic acid sensing methods generally rely on a ssDNA template that involves complementary bases to the endonuclease recognition sequence, which has the limitation of detecting only short nucleic acids. Herein, a new SDA method in which the defective T junction structure is first used to support SDA (dT-SDA) was proposed and applied in longer DNA detection. In dT-SDA, an auxiliary probe and a primer were designed to specifically identify the target gene, following the formation of a stable defective T junction structure through proximity hybridization, and the formation of defective T junctions could further trigger cascade SDA cycling to produce numerous ssDNA products. The quantity of these ssDNA products was detected through microchip electrophoresis (MCE) and could be transformed to the concentration of the target gene. Moreover, the applicability of this developed strategy in detecting long genomic DNA was verified by detecting bacterial 16S rDNA. This proposed dT-SDA strategy consumes less time and has satisfactory sensitivity, which has great potential for effective bacterial screening and infection diagnosis.

Simultaneous electrochemical determination of nuc and mecA genes for identification of methicillin-resistant Staphylococcus aureus using N-doped porous carbon and DNA-modified MOF.

The detection of Staphylococcus aureus specific gene in combination with the mecA gene is vitally important for accurate identification of methicillin-resistant Staphylococcus aureus (MRSA). A homogeneous electrochemical DNA sensor was fabricated for simultaneous detection of mecA and nuc gene in MRSA. Metal-organic framework (type UiO-66-NH2) was applied as nanocarrier. Two electroactive dyes, methylene blue (MB) and epirubicin (EP), were encapsulated in UiO-66-NH2, respectively, and were locked by the hybrid double-stranded DNA. Based on the target-response electroactive dye release strategy, once target DNA exists, it completely hybridizes with displacement DNA (DEP and DMB). So DEP and DMB is displaced from the MOF surface, causing the release of electroactive dyes. Co-Zn bimetallic zeolitic imidazolate framework-derived N-doped porous carbon serves for electrode modification to improve electrocatalytic performance and sensitivity. The differential pulse voltammetry peak currents of MB and EP were accurately detected at - 0.14 V and - 0.53 V versus the Ag/AgCl reference electrode, respectively. Under the optimal conditions, the detection limits of mecA gene and nuc gene were 3.7 fM and 1.6 fM, respectively. Combining the effective application of MOFs and the homogeneous detection strategy, the sensor exhibited satisfactory performance for MRSA identification in real samples. The recovery was 92.6-103%, and the relative standard deviation was less than 5%. Besides, MRSA and SA can also be distinguished. This sensor has great potential in practical applications.

Ultrasensitive microchip electrophoretic detection of the mecA gene in methicillin-resistant Staphylococcus aureus (MRSA) based on isothermal strand-displacement polymerase reaction.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main pathogens involved in hospital and community infection. To rapidly and sensitively detect the mecA gene, which is relevant to methicillin-resistant strains, microchip electrophoresis (MCE) integrated with isothermal strand-displacement polymerase reaction (ISDPR) was developed. In the ISDPR signal recycle amplification, the target DNA opened the DNA hairpin structure by specifically binding with the hairpin probe (HP), and then the primer hybridized with the probe and released the target DNA in the presence of Klenow Fragment exo- (KF exo-) polymerase. The released target DNA hybridized with the next HP and then was displaced by the primer again, consequently achieving target recycling and amplification. The amplified products of the HP-cDNA duplex were separated rapidly from other DNAs by MCE. Under optimal conditions, the limit of detection of the target DNA was as low as 12.3 pM (S/N = 3). The proposed ISDPR with MCE method was also successfully applied to detect methicillin-resistant S. aureus, and the experimental results showed that it had some advantages such as being label free, ultrasensitive, rapid and well separated.

Identification of Cell Status via Simultaneous Multitarget Imaging Using Programmable Scanning Electrochemical Microscopy.

A programmable multitarget-response electrochemical imaging technique was presented using scanning electrochemical microscopy (SECM) combined with a self-designed waveform. The potential waveform applied to the tip decreased the charging current caused by the potential switch, enhancing the signal-to-noise ratio. This programmable SECM (P-SECM) method was used to scan a metal strip for verifying its feasibility in feedback mode. Since it could achieve simultaneous multitarget imaging during one single imaging process, PC12 cells status was imaged and identified through three different molecules (FcMeOH, Ru(NH3)63+, and oxygen). The FcMeOH image eliminated the error from cell height, and the Ru(NH3)63+ image verified the change of membrane permeability. Moreover, the oxygen image demonstrated the bioactivity of the cell via its intensity of respiration. Combining information from these three molecules, the cell status could be determined accurately and also the error caused by time consumption with multiple scans in traditional SECM was eliminated.

Investigation of hydroxypropyl-ß-cyclodextrin-based synergistic system with chiral nematic mesoporous silica as chiral stationary phase for enantiomeric separation in microchip electrophoresis.

The separation of chiral amino acids using microchip electrophoresis (MCE) was investigated using chiral nematic mesoporous silica (CNMS) as the chiral stationary phase, with hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as the chiral selector. Individually, neither CNMS nor HP-ß-CD achieved separation, so they were combined. Ten chiral amino acids (phenylalanine, tryptophan, glutamic, alanine, serine, aspartic acid, cysteine, methionine, tyrosine, and histidine) were selected as the model analytes. Under optimized conditions, we achieved baseline separation of six chiral amino acids, and the other four chiral amino acids displayed improved resolution. These results indicate the presence of a synergistic effect between CNMS and HP-ß-CD, showing that the combination of a chiral stationary phase and a chiral additive is a promising approach for enantioseparation using MCE.

An electrochemical sensor for bacterial lipopolysaccharide detection based on dual functional Cu2+-modified metal-organic framework nanoparticles.

An electrochemical sensor based on dual functional Cu2+-modified metal-organic framework nanoparticles (Cu2+-NMOFs) for sensitive detection of bacterial lipopolysaccharide (LPS) is reported. Cu2+-NMOFs were prepared and characterized by SEM, EDS, XRD, and XPS. In this LPS sensor, LPS firstly immobilized in gold nanoparticles/reduced graphene oxide by C18 alkane thiol chains, since the LPS can interact with the C18 alkyl chains by strong intermolecular interactions. Then the Cu2+-NMOFs were captured by the anionic groups of the carbohydrate portions of LPS molecules and played a vital role of recognition unit. More importantly, the Cu2+-NMOFs can catalyze dopamine oxidation to generate aminochrome, resulting in a strong electrochemical oxidation signal. The electrochemical sensor based on dual functional Cu2+-NMOFs was investigated by differential pulse voltammetry, and the stripping peak currents of dopamine oxidized to aminochrome were used to monitor the level of LPS. The developed method demonstrated a wide linear range from 0.0015 to 750 ng/mL with a limit of detection of 6.1 × 10-4 ng/mL. The fabricated sensor was applied to detect LPS in mouse blood serum and satisfactory results were achieved. Compared to other detection schemes by using the LPS-binding proteins, peptides, and aptamer, the proposed LPS determination based on the catalytic peroxidase-mimicking NMOFs has some advantages such as good reproducibility, low detection limit, and excellent specificity. Graphical abstract An electrochemical sensor based on dual functional Cu2+-modified metal-organic framework was developed for detection of bacterial lipopolysaccharide. This sensor combined a metal ion-based target recognition and electrocatalytic detection, and provided a high sensitive strategy for detection of lipopolysaccharide.

Dual-signal electrochemical sensor for detection of cancer cells by the split primer ligation-triggered catalyzed hairpin assembly.

Simultaneous detection of various intracellular biomarkers is promising for early diagnosis and treatment of cancer. Herein, a split primer ligation-triggered catalyzed hairpin assembly-based on dual-signal electrochemical biosensor was constructed for the determination of two pairs of cancer mRNAs: TK1 and c-myc, survivin and GalNAc-T by using ferrocene molecular beacon and hemin molecular beacon as detection signal sources. Each pair of targets exists simultaneously, can release the split primers and ligated as the integral primers, hybridization occurred between the integral primers and part of MBs, causing a double-stranded DNA formed. The probes hybridized with the unfolded MBs and displaced integral primers. Finally, the displaced integral primers again hybridized with the MBs and initiated cycle amplification. Under the optimal conditions, the detection limit of TK1 and c-myc mRNA is as low as 0.022 nM, and that of survivin and GalNAc-T mRNA is 0.029 nM. In addition, two pairs of cancer mRNAs could act as outputs to activate an AND logic gate.

Real-time monitoring of extracellular pH using a pH-potentiometric sensing SECM dual-microelectrode.

Extracellular pH can indicate the variation in organelle function and cell state. It is important to measure extracellular pH (pHe) with a controllable distance. In this work, a potentiometric SECM dual-microelectrode was developed to monitor the pHe of MCF-7 cells under electrical stimulation. The distance between the dual-microelectrode and the cells was determined first with a gold microelectrode by recording the approaching curve, and the pH was determined using an open-circuit potential (OCP) technique with a polyaniline-modified Pt microelectrode. The pH microelectrode showed a response slope of 53.0 ± 0.4 mV/pH and good reversibility from pH 4 to pH 8, fast response within 10 s, and a potential drift of 1.13% for 3 h, and thus was employed to monitor the pHe of stimulated cells. The value of pHe decreased with the decrease in the distance to cells, likely due to the release of H+. With an increase in the stimulation potential or time, the pHe value decreased, as the cell membrane became more permeable, which was verified by fluorescence staining of calcein-AM/PI (propidium iodide). Based on these results, this method can be widely applied for determining the species released by biosystems at a controllable position.

Magneto-Mediated Electrochemical Sensor for Simultaneous Analysis of Breast Cancer Exosomal Proteins.

Breast cancer is a heterogeneous disease, and it lacks special tumor markers. Exosomes, new noninvasive biomarkers, with the proteins on the exosome surface show potential for the diagnosis and prognosis of a tumor. However, assessing the variations of exosomal proteins still faces significant challenges. Herein, a magneto-mediated electrochemical sensor based on host-guest recognition has been developed for simultaneous analysis of breast cancer exosomal proteins. Magnetic beads (MB) modified with CD63 aptamer was first employed to capture exosomes. Silica nanoparticles (SiO2 NPs) was modified with MUC1, HER2, EpCAM, and CEA aptamers for specific exosomal proteins identification, respectively, and functionalized with N-(2-((2-aminoethyl)disulfanyl)ethyl) ferrocene carboxamide (FcNHSSNH2) as the signal molecule. The sandwich structure (MB-exosomes-SiO2 NPs probe) was separated by a magnet, and N-(2-mercaptoethyl) ferrocene carboxamide (FcNHSH) was released to the supernatant by the addition of reductants (dithiothreitol, DTT) that break the disulfide bond of FcNHSSNH2. FcNHSH and the graphene oxide-cucurbit [7](GO-CB[7]) modified screen-printed carbon electrode (SPCE) was employed to monitor the oxidation current signals. In this way, four tumor markers on different breast cancer cells (MCF-7, SK-BR-3, MDA-MB-231, and BT474) derived exosomes were sensitively detected. Furthermore, the present assay enabled accurate analysis of exosomes from breast cancer patients, suggesting the potential of exosome analysis in clinic diagnosis.