Detection Of Exosomes Research Articles

Dual signal Amplification-Mediated Aptamer-Based electrochemical biosensor for sensitive detection of exosomes

Exosomes, a class of extracellular vesicles carrying the biological information of their parent cells, have emerged as one of the most promising biomarkers for the early screening and prognostic monitoring of cancer. However, the effective capture and sensitive detection of cancer cell-derived exosomes pose significant challenges due to the inevitable interference from internal environment and the limited exosome abundance in clinical samples. Herein, we proposed an aptamer-based electrochemical biosensor combining with Au nanoprobe-mediated dual signal amplification for sensitive detection of tumor-related exosomes. Benefiting from the specific recognition of CD63 aptamer (CD63 Apt), the target exosomes were efficiently captured on the gold electrode, followed by trapping the iDNA-modified Au nanoprobe, which could induce the generation of hybridization chain reaction (HCR). The long double-stranded DNA produced by HCR procedure provided numerous insertion sites to RuHex, achieving the high sensitivity for exosome detection. Under the optimal experimental conditions, this aptamer-based electrochemical biosensor for MCF-7 cancer cell-derived exosome detection exhibited a good linear range within 5 orders of magnitude (from 1.29 × 104 to 1.29 × 108 particle/mL) with a low limit of detection (LOD) to 1.65 × 103 particle/mL. Furthermore, this biosensor possessed good stability and anti-interference ability. Therefore, this analysis platform is considered as a promising candidate for the exosome-based diagnosis and prognosis of cancer in clinical applications.

CRISPR/Cas13a Trans-Cleavage and Catalytic Hairpin Assembly Cascaded Signal Amplification Powered SERS Aptasensor for Ultrasensitive Detection of Gastric Cancer-Derived Exosomes.

Cancer-derived exosomes carry a large number of specific molecular profiles from cancer cells and have emerged as ideal biomarkers for early cancer diagnosis. Accurate detection of ultralow-abundance exosomes in complex biological samples remains a great challenge. Herein, a novel SERS aptasensor powered by cascaded signal amplification of CRISPR/Cas13a trans-cleavage and catalytic hairpin assembly (CHA) was proposed for ultrasensitive detection of gastric cancer-derived exosomes, which included hairpin-structured recognition aptamers (MUC1-apt), cascaded signal amplification (i.e., CRISPR/Cas13a trans-cleavage and CHA), SERS tags, and silver nanorods (AgNRs) sensing chip. In the presence of SGC-7901 cell-derived exosomes, MUC1-apt specifically bound to MUC1 proteins highly expressed on exosomes via its contained MUC1 aptamer with its exposed RNA fragments activating the CRISPR/Cas13a trans-cleavage to cleave the uracil-modified hairpin reporter, and the cleavage products further triggered the downstream CHA reaction to form numerous duplexes, which can, in turn, capture a large number of SERS tags onto the AgNRs sensing chip to generate a significantly enhanced Raman signal. The proposed SERS aptasensor exhibits good performance on analysis of exosomes, i.e., rapid response within 60 min, single-particle sensitive detection from a 2 μL biological sample, good specificity in distinguishing SGC-7901 cell-derived exosomes against other exosomes, good uniformity, excellent repeatability, and satisfactory recoveries in human serum, and good universality to expand the detection of multiplex exosomes, which indicates that the SERS aptasensor provides a valuable reference for clinical diagnosis of early cancer.

Functional Immunoaffinity 3D Magnetic Core-Shell Nanometallic Structure for High-Efficiency Separation and Label-Free SERS Detection of Exosomes.

Tumor exosomes, known as maternal cell messengers, play an important role in cancer occurrence, proliferation, metastasis, immune escape, drug resistance, and other processes and are an entry point for cancer research. However, there is still a lack of an efficient detection technology for exosomes. In this study, the ultrahigh sensitivity SERS nanoprobe with a three dimensional (3D) magnetic core/Au nanocolumn/Au nanoparticles shell strongly coupling multistage structure (Fe3O4@NR-NPs) was constructed by crystal growth of nanocrystals in the confined space of a central radiating single particle mesoporous molecular sieve channel and strong coupling secondary growth of gold particles. The exosomes were confined onto the "hot spot" of plasmonic nanoparticles and rapidly enriched by CD63 antibody functional-Fe3O4@NR-NPs to achieve high sensitivity detection, with the limit of detection of 1 × 103 particles/mL (S/N = 3). The spectral data set of different exosomes is applied to train for multivariate classification of cell types and to estimate how the normal exosome data resemble cancer cell exosomes by principal component analysis (PCA). Finally, this detection method has also been successfully employed for the detection of exosomes in complex samples; this proves that the proposed SERS-based method is a promising tool for clinical cancer screening.

Electroactivated SERS Nanoplatform for Rapid and Sensitive Detection and Identification of Tumor-Derived Exosome miRNA.

Exosomal miRNA expression derived from tumor cells provides a valuable and promising noninvasive modality for the early diagnosis and assessment of the efficacy of cancer treatment. However, accurate detection and identification of miRNA within exosomes have been challenging due to its low abundance and the complexity and tedious extraction with large sample volumes in the separation process. Here, we developed an electrically activated nanoplatform for rapid and sensitive detection and identification of exosome miRNA, through triggering miRNA release by opening exosomes that were captured on the electrode surface using a slightly applied electric field (50 mV), and simultaneously detected them with surface-enhanced Raman spectroscopy (SERS) in situ. The method possessed superior specificity and sensitivity for exosomal miRNA detection, with a low detection concentration of 0.5 nM. The SERS sensor chips also showed a superior sensing performance of exosomal miRNA in complex body fluids such as urine and blood. We found that exosomal miRNA contents derived from tumor cells were significantly higher than those in normal cells, and importantly, the concentrations of exosomes secreted from three different cell lines were distinctly augmented after mild electrical stimulation (ES) treatment. Furthermore, the miRNA expression within exosomes was upregulated after the ES treatment of cells. The developed approach and SERS detection platform for exosomal miRNA are promising for noninvasive and precise screening, classification, and monitoring of cancer.

Integrating All-rounder TiO2 Accelerated Electrochemiluminescence with Dual-Quenching PDA@COF Probes for Sensitive Quantification and Protein Profiling of Tumorous Exosomes.

Exosomes have been perceived as promising biomarkers for noninvasive cancer diagnosis and treatment monitoring. However, the sensitive and accurate quantification and phenotyping of exosomes remains challenging. Herein, a versatile electrochemiluminescence (ECL) aptasensor was proposed for the sensitive analysis of tumorous exosomes. Specifically, a ternary nanohybrid (Ru-HAuTiO2), by covalently linking ECL luminophore Ru(dcbpy)32+ with gold nanoparticles (AuNPs)-decorated hollow urchin-like TiO2 (HTiO2), was ingeniously designed as a highly luminescent and self-enhanced ECL nanoemitter. Notably, the porous HTiO2 played an "all-rounder" role, including the carrier for ECL luminophores and AuNPs, coreaction accelerator, and specific exosome capturing scaffold through Ti-phosphate coordination interaction. On the other hand, a polydopamine modified covalent organic framework (PDA@COF) was employed as a quencher to remarkably attenuate the ECL of Ru-HAuTiO2 through a dual-quenching mechanism, and further labeled with a specific aptamer (Apt) of exosomal surface protein. Based on forming a Ru-HAuTiO2/exosome/Apt-PDA@COF sandwich structure on the electrode, a "signal on-off" ECL platform for tumorous exosomes was constructed, realizing sensitive detection within the range of 3.1 × 103 particles/mL to 1 × 108 particles/mL and a low limit of detection of 1.41 × 103 particles/mL, achieving phenotypic profiling of surface proteins on different tumorous exosomes. This work provides a promising alternative method for the detection and analysis of exosomes.

Aptamer-Functionalized Magnetic Ti3C2 Based Nanoplatform for Simultaneous Enrichment and Detection of Exosomes.

Exosomes are nanovesicles secreted by cells, which play a crucial role in various pathological processes. Exosomes have shown great promise as tumor biomarkers because of the abundant secretion during tumor formation. The development of a convenient, efficient, and cost-effective method for simultaneously enriching and detecting exosomes is of utmost importance for both basic research and clinical applications. In this study, an aptamer-functionalized magnetic Ti3C2 composite material (Fe3O4@Ti3C2@PEI@DSP@aptamer@FAM-ssDNA) is prepared for the simultaneous enrichment and detection of exosomes. CD63 aptamers are utilized to recognize and capture the exosomes, followed by magnetic separation. The exosomes are then released by cleaving the disulfide bonds of DSP. Compared to traditional methods, Fe3O4@Ti3C2@PEI@DSP@aptamer@FAM-ssDNA exhibited superior efficiency in enriching exosomes while preserving their structural and functional integrity. Detection of exosome concentration is achieved through the fluorescence quenching of Ti3C2 and the competitive binding between the exosomes and a fluorescently labeled probe. This method exhibited a low detection limit of 4.21 × 104 particlesmL-1, a number that is comparable to the state-of-the-art method in the detection of exosomes. The present study demonstrates a method of simultaneous enrichment and detection of exosomes with a high sensitivity, accuracy, specificity, and cost-effectiveness providing significant potential for clinical research and diagnosis.

Improved Isolation Optimizes Downstream Application of Extracellular Vesicles Derived from Mycobacterium tuberculosis.

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, secretes extracellular vesicles (EVs), which may play an important role in mediating interactions between bacteria and host cells. Mtb EVs can be isolated by means of various techniques, which differ in terms of their effectiveness. In the present study, we found that an exosome isolation kit (EI) yielded higher numbers of EVs than either differential centrifugation (DC) or exosome detection via an ultrafast-isolation system (EXODUS). We also found that the EXODUS method revealed a greater abundance of H37Rv components within EVs, compared with the DC and EI methods. Analysis of the downstream application of H37Rv EVs revealed their internalization by RAW264.7 macrophages, peaking at 6 h, with subsequent activation of the TLR2 signaling pathway leading to the expression of inflammatory cytokines including IL-6 and TNF-α. It was also found that H37Rv EVs could cross the blood-brain barrier (BBB) and enter the brain, peaking at 12 h post-injection, eliciting an inflammatory response in the cerebral parenchyma, cerebellum, and hippocampus that persisted for up to 6 days. These findings offer novel insights into the pathogenesis of Mtb-induced diseases and may guide the development of therapeutic strategies.

Terminal deoxynucleotidyl transferase (TdT) based template-free signal amplification for the detection of exosomes in MUC1-positive cells

The Mucin1 (MUC1) protein, involved in cytoprotective and signaling pathways, is abnormally elevated in various cancers, making it a key cancer indicator. Exosomes, which reflect the status of their originating cells, offer potential for cancer diagnosis. Thus, developing a method to detect MUC1-positive exosomes is crucial for the early diagnosis of certain cancers. In this study, we developed a highly sensitive, specific, and simple UV–visible signal amplification method to detect MUC1-positive exosomes using terminal deoxynucleotidyl transferase (TdT). Initially, exosomes were captured on magnetic beads using a CD63 aptamer(apt). The Primer-AuNPs-MUC1 apt complex which we synthesized by low pH loading method was then attached MUC1 proteins on the surface of the exosomes to create a sandwich structure. TdT catalyzed the extension of Biotin-dATP at the 3′ end of the primer, introducing multiple biotin sites into the sandwich structure. These sites subsequently bound multiple streptavidin-horseradish peroxidase (streptavidin-HRP), which catalyzed the oxidative color change of the substrate, which can be detected by colorimetric method. This method can detect A549 exosomes in the range of 1.4E+6 to 4.2E+8 particles/mL and shows high specificity for cell lines with different MUC1 expression. Additionally, it successfully distinguished cholangiocarcinoma (CCA) patients (n=11) from healthy individuals (n=7) in clinical serum assays, demonstrating good performance in real sample detection.

Concentration of kidney markers and detection of exosomes in urine samples collected in cotton wool balls in preterm and term neonates

Collecting urine samples in neonates by catheterisation or suprapubic puncture causes trauma, whereas self-adhesive collection bags can damage fragile skin. An alternative method is the collection of samples from urine-soaked cotton wool balls placed in diapers. The aim of this study was to compare the concentration of albumin, creatinine, neutrophil gelatinase-associated lipocalin (NGAL), and uromodulin between clean-catch urine and samples collected in cotton wool balls in neonates and assess the efficiency of exosome extraction. Standard clean-catch urine samples were assayed for albumin, creatinine, NGAL, and uromodulin using commercial enzyme-linked immunosorbent assay (ELISA) kits. Concentrations were compared to the same urine samples extracted immediately from soaked cotton wool balls (sample 2, S2) or the urine extracted from cotton wool balls placed in a diaper in a warm incubator for 2 h before extraction (sample 3, S3). Exosomes were extracted from all three samples of one patient for visualisation by electron microscopy. Twenty-six infants (17 males) of median gestational age at birth of 32+1 weeks had urine collected at a median age of 29 days at 37+6 weeks corrected age. Concentrations in S2 and S3 were within 10% of the concentration of standard samples in 46% and 35% of specimens for albumin, 69% and 58% for creatinine, 12% and 12% for NGAL, and 27% and 15% for uromodulin, respectively, without consistent positive or negative bias. Urine albumin/creatinine ratios (UACRs) were 4.3% less in S2 and 4.5% less in S3 than in standard samples. Exosomes were extracted and visualised from all three sample types. Neonatal urine samples extracted from cotton wool balls can be used to screen for relevant albuminuria ​but provide imprecise estimates of NGAL and uromodulin. The proof of exosome extraction from urine collection in cotton wool balls opens the potential to examine exosomal cargo.

Label-Free Exosome Analysis by Surface-Enhanced Raman Scattering Spectroscopy with Laser-Ablated Silver Nanoparticle Substrate.

Early diagnostics of breast cancer is crucial to reduce the risk of cancer metastasis and late relapse. Exosome, which contains distinct information of its origin, can be the target object as a liquid biopsy. However, its low sensitivity and inadequate diagnostic tools interfere with the point-of-care testing (POCT) of the exosome. Recently, Surface-enhanced Raman Scattering (SERS) spectroscopy, which amplifies the Raman scattering, has been proved as a promising tool for exosome detection. However, the fabrication process of SERS probe or substrate is still inefficient and far from large-scale production. This study proposes rapid and label-free detection of breast cancer-derived exosomes by statistical analysis of SERS spectra using silver-nanoparticle-based SERS substrate fabricated by selective laser ablation and melting (SLAM). Employing silver nanowires and optimizing laser process parameters enable rapid and low-energy fabrication of SERS substrate. The functionalities including sensitivity, reproducibility, stability, and renewability are evaluated using rhodamine 6G as a probe molecule. Then, the feasibility of POCT is examined by the statistical analysis of SERS spectra of exosomes from malignant breast cancer cells and non-tumorigenic breast epithelial cells. The presented framework is anticipated to be utilized in other biomedical applications, facilitating cost-effective and large-scale production performance.

Enhanced plasmonic scattering imaging via deep learning-based super-resolution reconstruction for exosome imaging.

Exosome analysis plays pivotal roles in various physiological and pathological processes. Plasmonic scattering microscopy (PSM) has proven to be an excellent label-free imaging platform for exosome detection. However, accurately detecting images scattered from exosomes remains a challenging task due to noise interference. Herein, we proposed an image processing strategy based on a new blind super-resolution deep learning neural network, named ESRGAN-SE, to improve the resolution of exosome PSI images. This model can obtain super-resolution reconstructed images without increasing experimental complexity. The trained model can directly generate high-resolution plasma scattering images from low-resolution images collected in experiments. The results of experiments involving the detection of light scattered by exosomes showed that the proposed super-resolution detection method has strong generalizability and robustness. Moreover, ESRGAN-SE achieved excellent results of 35.52036, 0.09081, and 8.13176 in terms of three reference-free image quality assessment metrics, respectively. These results show that the proposed network can effectively reduce image information loss, enhance mutual information between pixels, and decrease feature differentiation. And, the single-image SNR evaluation score of 3.93078 also showed that the distinction between the target and the background was significant. The suggested model lays the foundation for a potentially successful approach to imaging analysis. This approach has the potential to greatly improve the accuracy and efficiency of exosome analysis, leading to more accurate cancer diagnosis and potentially improving patient outcomes.

Nucleic Acid Amplification Circuit-Based Hydrogel (NACH) Assay for One-Step Detection of Metastatic Gastric Cancer-Derived Exosomal miRNA.

Gastric cancer (GC) is recognized as the fifth most prevalent malignant tumor worldwide. It is characterized by diverse clinical symptoms, treatment responses, and prognoses. In GC prognosis, the promotion of epithelial-mesenchymal transition (EMT) fosters cancer cell invasion and metastasis, thereby triggering the dissemination of tumor cells. This study proposes a nucleic acid amplification circuit-based hydrogel (NACH) assay for identifying exosomal miRNA derived from metastatic GC. The NACH assay employs the rolling circle amplification method and targets miRNA-21, a tumor-related oncogene, and miRNA-99a, which promotes EMT. Specific amplification probes for each target are immobilized within the hydrogel, enabling a streamlined, one-step amplification reaction. The NACH assay exhibits a detection limit of 1fm for miRNA-21 and miRNA-99a, thereby enabling rapid and highly sensitive on-site detection. Performance evaluation using exosomal miRNA extracted from cell culture media, mouse plasma, and human plasma revealed fluorescence intensity patterns similar to those obtained in qRT-PCR. Furthermore, deploying a custom-developed portable fluorometer for the NACH assay allows for diagnostic performance assessment and point-of-care testing using clinical samples from GC patients. These findings emphasize the potential of the NACH assay to be used as a robust tool for the genetic diagnosis of GC based on exosome detection.

Surface protein analysis of breast cancer exosomes using visualized strategy on centrifugal disk chip

Breast cancer, the most common cancer among women worldwide, lacks specific tumor markers for accurate diagnosis. Recent advances have highlighted tumor-derived exosomes as a promising non-invasive biomarker for cancer detection. Continuous monitoring of surface protein markers on exosomes in the blood could offer valuable insights for breast cancer diagnosis. However, integrating the isolation and detection of exosomes from whole blood is bulky, time-consuming, and requires professional operations. To address this difficulty, we developed a method of integrated centrifugal disk chip (CD chip) exosome enrichment directly from whole blood followed by a colorimetric visualization strategy for multiplex analysis. The disc consists of multi-chambers and multi-microchannels with immediate smartphone-enabled processing of colorimetric results. The combination of CEA + CA125 + EGFR on-chip detection could significantly differentiate the different stages of cancer in tumor-bearing mice and successfully distinguish between breast cancer patients and healthy individuals. Crucially, small volumes (100 μL) of blood samples were adequate. In addition, the chip was simple and fast, with results within 10 min, which provides immediate exosomal information through consecutive blood sampling, which could potentially result in a more timely and well-informed clinical breast cancer diagnosis.

Harnessing Spatiotemporal-Specific Tumorous Exosome Dynamics: Ultra-Sensitive Lanthanide Luminescence Detection Strategy Enabled by Exosomal Membrane Engineering for Melanoma Immunotherapy Monitoring.

Focused on the newly secreted tumorous exosomes during melanoma immunotherapy, this work has pioneered an ultra-sensitive spatiotemporal-specific exosome detection strategy, leveraging advanced exosomal membrane engineering techniques. The proposed strategy harnesses the power of amplified lanthanide luminescence signals on these exosomes, enabling precise and real-time monitoring of the efficacy of melanoma immunotherapy. The methodology comprises two pivotal steps. Initially, Ac4ManNAz-associated metabolic labeling is employed to evolve azide groups onto the membranes of newly secreted exosomes with remarkable selectivity. These azide groups serve as versatile clickable artificial tags, enabling the precise identification of melanoma exosomes emerging during immunotherapy. Subsequently, lanthanide-nanoparticle-functionalized polymer chains are controllably grafted onto the exosome surfaces through click chemistry and in situ Fenton-RAFT polymerization, serving as robust signal amplifiers. When integrated with time-resolved fluorescence detection, this strategy yields detection signals with an exceptionally high signal-to-noise ratio, enabling ultra-sensitive detection of PD-L1 antigen expression levels on the spatiotemporal-specific exosomes. The detection strategy boasts a wide linear concentration range spanning from 1.7 × 104 to 1.7 × 109 particles/mL, with a remarkable theoretical detection limit of 1.28 × 103 particles/mL. The remarkable enhancements in detection sensitivity and accuracy facilitate the evaluation of the efficacy of immunotherapeutic interventions in the mouse B16 melanoma model, notably revealing a substantial disparity in PD-L1 levels between immunotherapy-treated and untreated groups (P < 0.01) and further emphasizing the cumulative therapeutic effect that intensifies with repeated treatments (P < 0.001).

Exosome in renal cell carcinoma progression and implications for targeted therapy.

Renal cell carcinoma is a urological malignancy with a high metastatic rate, while targeted therapy for renal cell carcinoma still has much room for improvement. Some cutting-edge researches have focused on exosome in cancer treatment and there are some breakthroughs in breast cancer, lung cancer, and pancreatic cancer. Up to now, exosome in renal cell carcinoma progression and implications for targeted therapy has been under research by scientists. In this review, we have summarized the structure, formation, uptake, functions, and detection of exosomes, classified the mechanisms of exosomes that cause renal cell carcinoma progression, and listed the promising utilization of exosomes in targeted therapy for renal cell carcinoma. In all, based on the mechanisms of exosomes causing renal cell carcinoma progression and borrowing the successful experience from renal cell carcinoma models and other cancers, exosomes will possibly be a promising target for therapy in renal cell carcinoma in the foreseeable future.

Advances in exosome plasmonic sensing: Device integration strategies and AI-aided diagnosis

Exosomes, as next-generation biomarkers, has great potential in tracking cancer progression. They face many detection limitations in cancer diagnosis. Plasmonic biosensors have attracted considerable attention at the forefront of exosome detection, due to their label-free, real-time, and high-sensitivity features. Their advantages in multiplex immunoassays of minimal liquid samples establish the leading position in various diagnostic studies. This review delineates the application principles of plasmonic sensing technologies, highlighting the importance of exosomes-based spectrum and image signals in disease diagnostics. It also introduces advancements in miniaturizing plasmonic biosensing platforms of exosomes, which can facilitate point-of-care testing for future healthcare. Nowadays, inspired by the surge of artificial intelligence (AI) for science and technology, more and more AI algorithms are being adopted to process the exosome spectrum and image data from plasmonic detection. Using representative algorithms of machine learning has become a mainstream trend in plasmonic biosensing research for exosome liquid biopsy. Typically, these algorithms process complex exosome datasets efficiently and establish powerful predictive models for precise diagnosis. This review further discusses critical strategies of AI algorithm selection in exosome-based diagnosis. Particularly, we categorize the AI algorithms into the interpretable and uninterpretable groups for exosome plasmonic detection applications. The interpretable AI enhances the transparency and reliability of diagnosis by elucidating the decision-making process, while the uninterpretable AI provides high diagnostic accuracy with robust data processing by a “black-box” working mode. We believe that AI will continue to promote significant progress of exosome plasmonic detection and mobile healthcare in the near future.

Ultrasensitive Electrochemiluminescence Biosensor Based on DNA-Bio-Bar-Code and Hybridization Chain Reaction Dual Signal Amplification for Exosomes Detection.

Exosomes have received considerable attention as potent reference markers for the diagnosis of various neoplasms due to their close and direct relationship with the proliferation, adhesion, and migration of tumor. The ultrasensitive detection of cancer-derived low-abundance exosomes is imperative, but still a great challenge. Herein, we report an electrochemiluminescence (ECL) biosensor based on the DNA-bio-bar-code and hybridization chain reaction (HCR)-mediated dual signal amplification for the ultrasensitive detection of cancer-derived exosomes. In this system, two types of aptamers were modified on the magnetic nanoprobe (MNPs) and gold nanoparticles (AuNPs) with numerous bio-bar-code DNA, respectively, which formed "sandwich" structures in the presence of specific target exosomes. The "sandwich" structures were separated under magnetic field, and the numerous bio-bar-code DNA were released by dissolving AuNPs. The released bio-bar-code DNA triggered the HCR procedure to produce a good deal of long DNA duplex structure for embedding in hemin, which generated strong ECL signal in the presence of coreactors for ultrasensitive detection of exosomes. Under the optimal conditions, it exhibited a good linearly of exosomes ranging from 10 to 104 exosomes particle μL-1 with limit of detection down to 5.01 exosome particle μL-1. Furthermore, the high ratio of ECL signal and minor change of ECL intensity indicated the good specificity, stability, and repeatability of this ECL biosensor. Given the good performance for exosome analysis, this ultrasensitive ECL biosensor has a promising application in the clinical diagnosis of early cancers.

A Calibration Strategy for Silicon Nanowire Field-Effect Transistor Biosensors and Its Application in Ultra-Sensitive, Label-Free Biosensing.

The silicon nanowire field-effect transistor (SiNW FET) has been developed for over two decades as an ultrasensitive, label-free biosensor for biodetection. However, inconsistencies in manufacturing and surface functionalization at the nanoscale have led to poor sensor-to-sensor consistency in performance. Despite extensive efforts to address this issue through process improvements and calibration methods, the outcomes have not been satisfactory. Herein, based on the strong correlation between the saturation response of SiNW FET biosensors and both their feature size and surface functionalization, we propose a calibration strategy that combines the sensing principles of SiNW FET with the Langmuir-Freundlich model. By normalizing the response of the SiNW FET biosensors (ΔI/I0) with their saturation response (ΔI/I0)max, this strategy fundamentally overcomes the issues mentioned above. It has enabled label-free detection of nucleic acids, proteins, and exosomes within 5 min, achieving detection limits as low as attomoles and demonstrating a significant reduction in the coefficient of variation. Notably, the nucleic acid test results exhibit a strong correlation with the ultraviolet-visible (UV-vis) spectrophotometer measurements, with a correlation coefficient reaching 0.933. The proposed saturation response calibration strategy exhibits good universality and practicability in biological detection applications, providing theoretical and experimental support for the transition of mass-manufactured nanosensors from theoretical research to practical application.

Application of EXODUS system combined with allosteric DNA nanoswitches in the detection of miR-107 among plasma exosomes of Parkinson's disease patients

This study aimed to achieve rapid detection of Parkinson's disease (PD) plasma exosome miR-107. A case-control design was used to collect ten Parkinson's disease and ten healthy control plasma samples from the Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College of Huazhong University of Science and Technology from December 2023 to January 2024. Exosome detection via the ultrafast-isolation system (EXODUS) was used to isolate plasma exosomes. The nanoparticle tracking analysis technology and electron microscopy were used to identify exosome particle size and morphology. The Qiagen miRNeasy Micro Kit was used to extract RNA. The microRNA-activated conditional looping of engineered switches (miRacles) was used to detect miR-107, and the relative expression was analyzed by agarose gel electrophoresis. Thermo Fisher RevertAid RT Reverse Transcription Kit was used to perform reverse transcription of RNA, and real-time PCR was used to detect miR-107. The independent samples t-test was used for comparison between groups. EXODUS system completed the isolation of exosomes from 500 μl plasma within 1.5 hours. The exosome concentration (mean±SD) was (4.82±2.02)×1010 particles/ml in the control group and (5.08±2.34)×1010 particles/ml in the PD group. There was no significant difference in exosome concentration between PD patients and healthy controls (t=-0.168, P=0.872). The morphology of exosomes was confirmed by electron microscopy. The miRacles nanoswitch could detect fM-level miR-107 and also effectively distinguish miR-107 from its family members, including miR-15a and miR-16. Agarose gel electrophoresis showed that the mean±SD of relative grey value content was 1.00±0.26 in the control group and 1.86±0.21 in the PD group. The miR-107 in the PD group was significantly higher than that in the control (t=-8.143, P<0.001), which was consistent with the result of real-time PCR. EXODUS combined with miRacles could achieve rapid, non-enzymatic and cheap detection of plasma exosomal miR-107 in PD patients.

Advancements in Nano-Mediated Biosensors: Targeting Cancer Exosome Detection

Advancements in Nano-Mediated Biosensors: Targeting Cancer Exosome Detection