Protein typing of circulating microvesicles allows real-time monitoring of glioblastoma therapy

Microparticles in Autoimmunity: Cause or Consequence of Disease?

Microparticles (MPs) are small (100 nm - 1 um) extracellular vesicles derived from the plasma membrane of dying or activated cells. MPs are important mediators of intercellular communication, transporting proteins, nucleic acids and lipids from the parent cell to other cells. MPs resemble the state of their parent cells and are easily accessible when released into the blood or urine. MPs also play a role in the pathogenesis of different diseases and are considered as potential biomarkers. MP isolation and characterization is technically challenging and results in different studies are contradictory. Therefore, uniform guidelines to isolate and characterize MPs should be developed. Our understanding of MP biology and how MPs play a role in different pathological mechanisms has greatly advanced in recent years. MPs, especially if derived from apoptotic cells, possess strong immunogenic properties due to the presence of modified proteins and nucleic acids. MPs are often found in patients with autoimmune diseases where MPs for example play a role in the break of immunological tolerance and/or induction of inflammatory conditions. In this review, we describe the main techniques to isolate and characterize MPs, define the characteristics of MPs generated during cell death, illustrate different mechanism of intercellular communication via MPs and summarize the role of MPs in pathological mechanisms with a particular focus on autoimmune diseases.

Clair DK. Extracellular vesicles released after cranial radiation: An insight into an early mechanism of brain injury

Cranial radiation is important for treating both primary brain tumors and brain metastases. A potential delayed side effect of cranial radiation is neurocognitive function decline. Early detection of CNS injury might prevent further neuronal damage. Extracellular vesicles (EVs) have emerged as a potential diagnostic tool because of their unique membranous characteristics and cargos. We investigated whether EVs can be an early indicator of CNS injury by giving C57BJ/6 mice 10 Gy cranial IR. EVs were isolated from sera to quantify: 1) number of EVs using nanoparticle tracking analysis (NTA); 2) Glial fibrillary acidic protein (GFAP), an astrocyte marker; and 3) protein-bound 4-hydroxy-2-nonenal (HNE) adducts, an oxidative damage marker. Brain tissues were prepared for immunohistochemistry staining and protein immunoblotting. The results demonstrate: 1) increased GFAP levels (p < 0.05) in EVs, but not brain tissue, in the IR group; and 2) increased HNE-bound protein adduction levels (p < 0.05). The results support using EVs as an early indicator of cancer therapy-induced neuronal injury.

Application of exosomes in the diagnosis and treatment of pancreatic diseases

Pancreatic diseases, a serious threat to human health, have garnered considerable research interest, as they are associated with a high mortality rate. However, owing to the uncertain etiology and complex pathophysiology, the treatment of pancreatic diseases is a challenge for clinicians and researchers. Exosomes, carriers of intercellular communication signals, play an important role in the diagnosis and treatment of pancreatic diseases. Exosomes are involved in multiple stages of pancreatic disease development, including apoptosis, immune regulation, angiogenesis, cell migration, and cell proliferation. Thus, extensive alterations in the quantity and variety of exosomes may be indicative of abnormal biological behaviors of pancreatic cells. This phenomenon could be exploited for the development of exosomes as a new biomarker or target of new treatment strategies. Several studies have demonstrated the diagnostic and therapeutic effects of exosomes in cancer and inflammatory pancreatic diseases. Herein, we introduce the roles of exosomes in the diagnosis and treatment of pancreatic diseases and discuss directions for future research and perspectives of their applications.

Exosomes as Promising Nanostructures in Diabetes Mellitus: From Insulin Sensitivity to Ameliorating Diabetic Complications

Diabetes mellitus (DM) is among the chronic metabolic disorders that its incidence rate has shown an increase in developed and wealthy countries due to lifestyle and obesity. The treatment of DM has always been of interest, and significant effort has been made in this field. Exosomes belong to extracellular vesicles with nanosized features (30-150 nm) that are involved in cell-to-cell communication and preserving homeostasis. The function of exosomes is different based on their cargo, and they may contain lipids, proteins, and nucleic acids. The present review focuses on the application of exosomes in the treatment of DM; both glucose and lipid levels are significantly affected by exosomes, and these nanostructures enhance lipid metabolism and decrease its deposition. Furthermore, exosomes promote glucose metabolism and affect the level of glycolytic enzymes and glucose transporters in DM. Type I DM results from the destruction of β cells in the pancreas, and exosomes can be employed to ameliorate apoptosis and endoplasmic reticulum (ER) stress in these cells. The exosomes have dual functions in mediating insulin resistance/sensitivity, and M1 macrophage-derived exosomes inhibit insulin secretion. The exosomes may contain miRNAs, and by transferring among cells, they can regulate various molecular pathways such as AMPK, PI3K/Akt, and β-catenin to affect DM progression. Noteworthy, exosomes are present in different body fluids such as blood circulation, and they can be employed as biomarkers for the diagnosis of diabetic patients. Future studies should focus on engineering exosomes derived from sources such as mesenchymal stem cells to treat DM as a novel strategy.

Microfluidic platforms for extracellular vesicle isolation, analysis and therapy in cancer

Extracellular vesicles (EVs) are small lipidic particles packed with proteins, DNA, messenger RNA and microRNAs of their cell of origin that act as critical players in cell-cell communication. These vesicles have been identified as pivotal mediators in cancer progression and the formation of metastatic niches. Hence, their isolation and analysis from circulating biofluids is envisioned as the next big thing in the field of liquid biopsies for early non-invasive diagnosis and patient follow-up. Despite the promise, current benchtop isolation strategies are not compatible with point-of-care testing in a clinical setting. Microfluidic platforms are disruptive technologies capable of recovering, analyzing, and quantifying EVs within clinical samples with limited volume, in a high-throughput manner with elevated sensitivity and multiplexing capabilities. Moreover, they can also be employed for the controlled production of synthetic EVs and effective drug loading to produce EV-based therapies. In this review, we explore the use of microfluidic platforms for the isolation, characterization, and quantification of EVs in cancer, and compare these platforms with the conventional methodologies. We also highlight the state-of-the-art in microfluidic approaches for EV-based cancer therapeutics. Finally, we analyze the currently active or recently completed clinical trials involving EVs for cancer diagnosis, treatment or therapy monitoring and examine the future of EV-based point-of-care testing platforms in the clinic and EV-based therapy production by the industry.

Circulating Abnormal Extracellular Vesicles: Their Mechanism for Crossing Blood-Brain Barrier, Effects on Central Nervous System and Detection Methods

Central nervous system (CNS) diseases are difficult to treat and harmful. Many CNS diseases are secondary to peripheral diseases, such as tumor brain metastases (BMS), viral infections and inflammation of the brain, and their pathogenic factors travel through the circulatory system to the brain, eventually leading to lesions. Extracellular vesicles (EVs) play an important role in this process. Recent studies have shown that, extracellular EVs can effectively cross the blood- brain barrier (BBB) through endocytosis and they transmit molecular signals in cell-to-cell communication. Abnormal EVs produced in the lesion portion transport pathogenic factors, including miRNAs, proteins, and virions into the CNS. These pathogenic factors participate in cellular pathways to interfere with homeostasis or are themselves pathogens that directly damage CNS. In addition, different or specific pathological molecules in EVs are potential disease markers. We herein reviewed pathways through which the abnormal EVs cross BBB and adverse effects of abnormal exosomes. We also and summarized their existing detection techniques, so as to provide basis for prevention and early diagnosis of secondary diseases.

Enhanced Chemodynamic Therapy by Cu-Fe Peroxide Nanoparticles: Tumor Microenvironment-Mediated Synergistic Fenton Reaction

An urgent need in chemodynamic therapy (CDT) is to achieve high Fenton catalytic efficiency at small doses of CDT agents. However, simple general promotion of the Fenton reaction increases the risk of damaging normal cells along with the cancer cells. Therefore, a tailored strategy to selectively enhance the Fenton reactivity in tumors, for example, by taking advantage of the characteristics of the tumor microenvironment (TME), is in high demand. Herein, a heterogeneous CDT system based on copper-iron peroxide nanoparticles (CFp NPs) is designed for TME-mediated synergistic therapy. CFp NPs degrade under the mildly acidic conditions of TME, self-supply H₂O₂, and the released Cu and Fe ions, with their larger portions at lower oxidation states, cooperatively facilitate hydroxyl radical production through a highly efficient catalytic loop to achieve an excellent tumor therapeutic efficacy. This is distinct from previous heterogeneous CDT systems in that the synergism is closely coupled with the Cu⁺-assisted conversion of Fe³⁺ to Fe²⁺ rather than their independent actions. As a result, almost complete ablation of tumors at a minimal treatment dose is demonstrated without the aid of any other therapeutic modality. Furthermore, CFp NPs generate O₂ during the catalysis and exhibit a TME-responsive T₁ magnetic resonance imaging contrast enhancement, which are useful for alleviating hypoxia and in vivo monitoring of tumors, respectively.

Modernistic and Emerging Developments of Nanotechnology in Glioblastoma-Targeted Theranostic Applications

Brain tumors such as glioblastoma are typically associated with an unstoppable cell proliferation with aggressive infiltration behavior and a shortened life span. Though treatment options such as chemotherapy and radiotherapy are available in combating glioblastoma, satisfactory therapeutics are still not available due to the high impermeability of the blood–brain barrier. To address these concerns, recently, multifarious theranostics based on nanotechnology have been developed, which can deal with diagnosis and therapy together. The multifunctional nanomaterials find a strategic path against glioblastoma by adjoining novel thermal and magnetic therapy approaches. Their convenient combination of specific features such as real-time tracking, in-depth tissue penetration, drug-loading capacity, and contrasting performance is of great demand in the clinical investigation of glioblastoma. The potential benefits of nanomaterials including specificity, surface tunability, biodegradability, non-toxicity, ligand functionalization, and near-infrared (NIR) and photoacoustic (PA) imaging are sufficient in developing effective theranostics. This review discusses the recent developments in nanotechnology toward the diagnosis, drug delivery, and therapy regarding glioblastoma.

Multielectrode Spectroscopy Enables Rapid and Sensitive Molecular Profiling of Extracellular Vesicles

Detecting protein markers in extracellular vesicles (EVs) is becoming a useful tool for basic research and clinical diagnoses. Most EV protein assays, however, require lengthy processes-conjugating affinity ligands onto sensing substrates and affixing EVs with additional labels to maximize signal generation. Here, we present an iPEX (impedance profiling of extracellular vesicles) system, an all-electrical strategy toward fast, multiplexed EV profiling. iPEX adopts one-step electropolymerization to rapidly functionalize sensor electrodes with antibodies; it then detects EV proteins in a label-free manner through impedance spectroscopy. The approach streamlines the entire EV assay, from sensor preparation to signal measurements. We achieved (i) fast immobilization of antibodies (<3 min) per electrode; (ii) high sensitivity (500 EVs/mL) without secondary labeling; and (iii) parallel detection (quadruple) in a single chip. A potential clinical utility was demonstrated by directly analyzing plasma samples from glioblastoma multiforme patients.

MPAPASS software enables stitched multiplex, multidimensional EV repertoire analysis and a standard framework for reporting bead-based assays

Extracellular vesicles (EVs) of various types are released or shed from all cells. EVs carry proteins and contain additional protein and nucleic acid cargo that relates to their biogenesis and cell of origin. EV cargo in liquid biopsies is of widespread interest owing to its ability to provide a retrospective snapshot of cell state at the time of EV release. For the purposes of EV cargo analysis and repertoire profiling, multiplex assays are an essential tool in multiparametric analyte studies but are still being developed for high-parameter EV protein detection. Although bead-based EV multiplex analyses offer EV profiling capabilities with conventional flow cytometers, the utilization of EV multiplex assays has been limited by the lack of software analysis tools for such assays. To facilitate robust EV repertoire studies, we developed multiplex analysis post-acquisition analysis (MPAPASS) open-source software for stitched multiplex analysis, EV database-compatible reporting, and visualization of EV repertoires.

Glutathione-functionalized magnetic thioether-COFs for the simultaneous capture of urinary exosomes and enrichment of exosomal glycosylated and phosphorylated peptides

Exosomes play an irreplaceable role in physiological and pathological processes, and the study of proteomics (especially protein post-translational modifications, PTMs) in exosomes can reveal the pathogenesis of diseases and screen therapeutic disease targets. The separation and enrichment process is an essential step in mass spectroscopy-based exosomal PTMs studies to reduce sample complexity and ionization-suppression effects. Herein, we designed a novel magnetic zwitterionic material, namely glutathione-functionalized thioether covalent organic frameworks (Fe₃O₄@Thio-COF@Au@GSH), possessing fast magnetic responsiveness, regular porosity, and a suitable surface area. Thanks to the hydrophilicity and charge-switchable feature of GSH, for the first time, both the capture of exosomes from biological fluids and enrichment of the inherent glycoproteins/phosphoproteins in the exosomes were achieved with the same material. Furthermore, the high enrichment capacity was validated by theoretical calculations. The low detection limits (0.2/0.4 fmol for HRP/β-casein), high selectivity (1 : 1000 for HRP/β-casein : BSA molar ratio), and high exosomal glycoproteomics/phosphoproteomics profiling capability proved the feasibility of the developed method. This work provides a new heuristic strategy to solve the problems of exosomal capture and glycoproteins/phosphoproteins pretreatment in exosomal proteomics.

Exosomes: the key of sophisticated cell-cell communication and targeted metastasis in pancreatic cancer

Pancreatic cancer is one of the most common malignancies. Unfortunately, the lack of effective methods of treatment and diagnosis has led to poor prognosis coupled with a very high mortality rate. So far, the pathogenesis and progression mechanisms of pancreatic cancer have been poorly characterized. Exosomes are small vesicles secreted by most cells, contain lipids, proteins, and nucleic acids, and are involved in diverse functions such as intercellular communications, biological processes, and cell signaling. In pancreatic cancer, exosomes are enriched with multiple signaling molecules that mediate intercellular communication with control of immune suppression, mutual promotion between pancreas stellate cells and pancreatic cancer cells, and reprogramming of normal cells. In addition, exosomes can regulate the pancreatic cancer microenvironment and promote the growth and survival of pancreatic cancer. Exosomes can also build pre-metastatic micro-ecological niches and facilitate the targeting of pancreatic cancer. The ability of exosomes to load cargo and target allows them to be of great clinical value as a biomarker mediator for targeted drugs in pancreatic cancer. Video Abstract.

Using genetically modified extracellular vesicles as a non-invasive strategy to evaluate brain-specific cargo

The lack of techniques to trace brain cell behavior in vivo hampers the ability to monitor status of cells in a living brain. Extracellular vesicles (EVs), nanosized membrane-surrounded vesicles, released by virtually all brain cells might be able to report their status in easily accessible biofluids, such as blood. EVs communicate among tissues using lipids, saccharides, proteins, and nucleic acid cargo that reflect the state and composition of their source cells. Currently, identifying the origin of brain-derived EVs has been challenging, as they consist of a rare population diluted in an overwhelming number of blood and peripheral tissue-derived EVs. Here, we developed a sensitive platform to select out pre-labelled brain-derived EVs in blood as a platform to study the molecular fingerprints of brain cells. This proof-of-principle study used a transducible construct tagging tetraspanin (TSN) CD63, a membrane-spanning hallmark of EVs equipped with affinity, bioluminescent, and fluorescent tags to increase detection sensitivity and robustness in capture of EVs secreted from pre-labelled cells into biofluids. Our platform enables unprecedented efficient isolation of neural EVs from the blood. These EVs derived from pre-labelled mouse brain cells or engrafted human neuronal progenitor cells (hNPCs) were submitted to multiplex analyses, including transcript and protein levels, in compliance with the multibiomolecule EV carriers. Overall, our novel strategy to track brain-derived EVs in a complex biofluid opens up new avenues to study EVs released from pre-labelled cells in near and distal compartments into the biofluid source.

Liquid biopsy in gliomas: A RANO review and proposals for clinical applications

BACKGROUND

There is an extensive literature highlighting the utility of blood-based liquid biopsies in several extracranial tumors for diagnosis and monitoring.

METHODS

The RANO (Response Assessment in Neuro-Oncology) group developed a multidisciplinary international Task Force to review the English literature on liquid biopsy in gliomas focusing on the most frequently used techniques, that is circulating tumor DNA, circulating tumor cells, and extracellular vesicles in blood and CSF.

RESULTS

ctDNA has a higher sensitivity and capacity to represent the spatial and temporal heterogeneity in comparison to circulating tumor cells. Exosomes have the advantages to cross an intact blood-brain barrier and carry also RNA, miRNA, and proteins. Several clinical applications of liquid biopsies are suggested: to establish a diagnosis when tissue is not available, monitor the residual disease after surgery, distinguish progression from pseudoprogression, and predict the outcome.

CONCLUSIONS

There is a need for standardization of biofluid collection, choice of an analyte, and detection strategies along with rigorous testing in future clinical trials to validate findings and enable entry into clinical practice.

Si nanowire Bio-FET for electrical and label-free detection of cancer cell-derived exosomes

Exosomes are highly important in clinical diagnosis due to their high homology with their parental cells. However, conventional exosome detection methods still face the challenges of expensive equipment, low sensitivity, and complex procedures. Field effect transistors (FETs) are not only the most essential electronic component in the modern microelectronics industry but also show great potential for biomolecule detection owing to the advantages of rapid response, high sensitivity, and label-free detection. In this study, we proposed a Si nanowire field-effect transistor (Si-NW Bio-FET) device chemically modified with specific antibodies for the electrical and label-free detection of exosomes. The Si-NW FETs were fabricated by standard microelectronic processes with 45 nm width nanowires and packaged in a polydimethylsiloxane (PDMS) microfluidic channel. The nanowires were further modified with the specific CD63 antibody to form a Si-NW Bio-FET. The use of the developed Si-NW Bio-FET for the electrical and label-free detection of exosomes was successfully demonstrated with a limit of detection (LOD) of 2159 particles/mL. In contrast to other technologies, in this study, Si-NW Bio-FET provides a unique strategy for directly quantifying and real-time detecting exosomes without labeling, indicating its potential as a tool for the early diagnosis of cancer.

Molecularly Imprinted Polymers in Diagnostics: Accessing Analytes in Biofluids

Bio-applied molecularly imprinted polymers (MIPs) are biomimetic materials with tailor-made synthetic recognition sites, mimicking biological counterparts known for their sensitive and selective analyte detection. MIPs, specifically designed for biomarker analysis...

Role of extracellular vesicles in osteosarcoma

Osteosarcoma is a malignant bone tumor characterized by the direct production of osteoid tissue from tumor cells. Extracellular vesicles are membranous vesicles released by cells into the extracellular matrix, which exist widely in various body fluids and cell supernatants, and stably carry some important signaling molecules. They are involved in cell communication, cell migration, angiogenesis and tumor cell growth. Increasing evidence has shown that extracellular vesicles play a significant role in osteosarcoma development, progression, and metastatic process, indicating that extracellular vesicles can be use as biomarker vehicles in the diagnosis and prognosis of osteosarcoma. This review discusses the basic biological characteristics of extracellular vesicles and focuses on their application in osteosarcoma.

Improving the diagnostic efficacy of squamous cell carcinoma antigen for oral squamous cell carcinoma via saponin disruption of serum extracellular vesicles

BACKGROUND

The diagnostic value of squamous cell carcinoma antigen (SCCA) for oral squamous cell carcinoma (OSCC) is insufficient. Recently, extracellular vesicles (EVs) have displayed great potential for improving diagnostic efficacy. However, one of the main challenges that restricts the application of EVs is the lack of a clinically suitable separation method for the intra-vesicular protein detection.

METHODS

Saponin was used to destroy serum EVs membranes for releasing the intra-vesicular SCCA into the serum, circumventing the purification process of EVs. The concentrations of SCCA were measured and compared in 113 healthy people and 73 OSCC patients pre- and post-saponin treatment.

RESULTS

The concentration of serum SCCA significantly increased after saponin destroyed the membrane of EVs. The area under the curve (AUC) of serum SCCA for OSCC diagnosis was 0.6444 (95% CI, 0.5595 to 0.7293). The diagnostic AUC of serum EVs-derived SCCA reached 0.7969 (95% CI, 0.735 to 0.8588).

CONCLUSIONS

The results suggested that serum EVs disrupted by saponin could improve the diagnostic efficacy of SCCA for OSCC, which provides a simple, rapid, and high-throughput method to detect the intra-vesicular proteins of EVs and holds great potential for clinical application.

The emerging role of extracellular vesicles in retinal diseases

As a type of nanosized membranous vesicles secreted by living cells, extracellular vesicles (EVs) mediate intercellular communications with excellent physicochemical stability and biocompatibility. By delivering biologically active molecules including proteins, nucleic acids and lipids, EVs participate in many physiological and pathological processes. Increasing studies have suggested that EVs may be biomarkers for liquid biopsy of retinal diseases due to the ability to transfer through the blood-retinal barrier. EVs also represent a novel cell-free strategy to repair tissue damage in regenerative medicine. Evidence has indicated that EVs can be engineered and modified to enhance their efficacy. In this review, an overview of the characteristics, isolation, and identification of EVs is provided. Moreover, recent advances with EVs in the diagnosis and treatment of retinal diseases and the engineering approaches to elevate their effects are introduced, and opportunities and challenges for clinical application are discussed.

Tango of dual nanoparticles: Interplays between exosomes and nanomedicine

Exosomes are lipid bilayer vesicles released from cells as a mechanism of intracellular communication. Containing information molecules of their parental cells and inclining to fuse with targeted cells, exosomes are valuable in disease diagnosis and drug delivery. The realization of their clinic applications still faces difficulties, such as lacking technologies for fast purification and functional reading. The advancement of nanotechnology in recent decades makes it promising to overcome these difficulties. In this article, we summarized recent progress in utilizing the physiochemical properties of nanoparticles (NPs) to enhance exosome purification and detection sensitivity or to derive novel technologies. We also discussed the valuable applications of exosomes in NPs‐based drug delivery. Till now most studies in these fields are still at the laboratory research stage. Translation of these bench works into clinic applications still has a long way to go.

Advances in Biosensors Technology for Detection and Characterization of Extracellular Vesicles

Exosomes are extracellular vehicles (EVs) that encapsulate genomic and proteomic material from the cell of origin that can be used as biomarkers for non-invasive disease diagnostics in point of care settings. The efficient and accurate detection, quantification, and molecular profiling of exosomes are crucial for the accurate identification of disease biomarkers. Conventional isolation methods, while well-established, provide the co-purification of proteins and other types of EVs. Exosome purification, characterization, and OMICS analysis are performed separately, which increases the complexity, duration, and cost of the process. Due to these constraints, the point-of-care and personalized analysis of exosomes are limited in clinical settings. Lab-on-a-chip biosensing has enabled the integration of isolation and characterization processes in a single platform. The presented review discusses recent advancements in biosensing technology for the separation and detection of exosomes. Fluorescent, colorimetric, electrochemical, magnetic, and surface plasmon resonance technologies have been developed for the quantification of exosomes in biological fluids. Size-exclusion filtration, immunoaffinity, electroactive, and acoustic-fluid-based technologies were successfully applied for the on-chip isolation of exosomes. The advancement of biosensing technology for the detection of exosomes provides better sensitivity and a reduced signal-to-noise ratio. The key challenge for the integration of clinical settings remains the lack of capabilities for on-chip genomic and proteomic analysis.

The Past, the Present, and the Future of the Size Exclusion Chromatography in Extracellular Vesicles Separation

Extracellular vesicles (EVs) are cell-derived membranous particles secreted by all cell types (including virus infected and uninfected cells) into the extracellular milieu. EVs carry, protect, and transport a wide array of bioactive cargoes to recipient/target cells. EVs regulate physiological and pathophysiological processes in recipient cells and are important in therapeutics/drug delivery. Despite these great attributes of EVs, an efficient protocol for EV separation from biofluids is lacking. Numerous techniques have been adapted for the separation of EVs with size exclusion chromatography (SEC)-based methods being the most promising. Here, we review the SEC protocols used for EV separation, and discuss opportunities for significant improvements, such as the development of novel particle purification liquid chromatography (PPLC) system capable of tandem purification and characterization of biological and synthetic particles with near-single vesicle resolution. Finally, we identify future perspectives and current issues to make PPLC a tool capable of providing a unified, automated, adaptable, yet simple and affordable particle separation resource.

Nanoparticle-Enabled Multiplexed Electrochemical Immunoassay for Detection of Surface Proteins on Extracellular Vesicles

Extracellular vesicles (EVs) are lipid bilayer particles secreted from various cells. EVs carry molecular information of parent cells and hold considerable promise for early disease diagnostics. This paper describes a general strategy for multiplexed immunosensing of EV surface proteins, focusing on surface markers CD63, CD81, nephrin, and podocin to prove the concept. This sensing strategy entailed functionalizing gold nanoparticles (AuNPs) with two types of antibodies and then tagging with metal ions, either Pb2+ or Cu2+. The metal ions served as redox reporters, generating unique redox peaks at -0.23 and 0.28 V (vs Ag/AgCl) during electrochemical oxidation of Pb2+ and Cu2+, respectively. Capture of EVs on the working electrode, followed by labeling with immunoprobes and square wave voltammetry, produced redox currents proportional to concentrations of EVs and levels of expression of EV surface markers. Importantly, metal-ion tagging of immunoprobes enabled detection of two EV surface markers simultaneously from the same electrode. We demonstrated dual detection of either CD63/CD81 or podocin/nephrin surface markers from urinary EVs. The NP-enabled immunoassay had a sensitivity of 2.46 × 105 particles/mL (or 40.3 pg/mL) for CD63- and 5.80 × 105 particles/mL (or 47.7 pg/mL) for CD81-expressing EVs and a linear range of four orders of magnitude. The limit of detection for podocin and nephrin was 3.1 and 3.8 pg/mL, respectively. In the future, the capacity for multiplexing may be increased by extending the repertoire of metal ions used for redox tagging of AuNPs.

Small extracellular vesicles in cancer

Extracellular vesicles (EV) are lipid-bilayer enclosed vesicles in submicron size that are released from cells. A variety of molecules, including proteins, DNA fragments, RNAs, lipids, and metabolites can be selectively encapsulated into EVs and delivered to nearby and distant recipient cells. In tumors, through such intercellular communication, EVs can regulate initiation, growth, metastasis and invasion of tumors. Recent studies have found that EVs exhibit specific expression patterns which mimic the parental cell, providing a fingerprint for early cancer diagnosis and prognosis as well as monitoring responses to treatment. Accordingly, various EV isolation and detection technologies have been developed for research and diagnostic purposes. Moreover, natural and engineered EVs have also been used as drug delivery nanocarriers, cancer vaccines, cell surface modulators, therapeutic agents and therapeutic targets. Overall, EVs are under intense investigation as they hold promise for pathophysiological and translational discoveries. This comprehensive review examines the latest EV research trends over the last five years, encompassing their roles in cancer pathophysiology, diagnostics and therapeutics. This review aims to examine the full spectrum of tumor-EV studies and provide a comprehensive foundation to enhance the field. The topics which are discussed and scrutinized in this review encompass isolation techniques and how these issues need to be overcome for EV-based diagnostics, EVs and their roles in cancer biology, biomarkers for diagnosis and monitoring, EVs as vaccines, therapeutic targets, and EVs as drug delivery systems. We will also examine the challenges involved in EV research and promote a framework for catalyzing scientific discovery and innovation for tumor-EV-focused research.

Rolling Circle Amplification-Assisted Flow Cytometry Approach for Simultaneous Profiling of Exosomal Surface Proteins

Exosomes that carry multiple proteins from the originating cells are known as emerging biomarkers for tumor diagnostics. However, it is still technically challenging to accurately evaluate subtle differences of exosomal membrane proteins. Here, we developed a rolling circle amplification (RCA)-assisted flow cytometry approach (FCA) to simultaneously profile surface proteins and quantify exosomes. In this work, specific anti-CD63 antibody-conjugated magnetic beads were first utilized to capture exosomes. Then, the captured exosomes were bound with DNA primers, which comprise exosomal surface protein-specific recognition aptamers. The RCA reaction generates repeat DNA sequences for fluorescent probe hybridization. Finally, a conventional flow cytometer was introduced to phenotype exosomal protein markers. Such a sensitive RCA-assisted FCA displays an excellent detection limit of 1.3 × 10⁵ exosome/mL. The variable composition of four protein markers on different cell-derived exosomes was sensitively detected through changing the protein-recognition sequence of the DNA primer, which reveals a heterogeneous pattern. Exosomes from different cell sources could be distinguished by the abundance difference of multiple surface proteins. Furthermore, the developed RCA-assisted FCA enabled quantitative analysis of blood samples from lung cancer patients, indicating its potential for early clinical diagnosis and prognosis of cancer.

Exosomes and Brain Metastases: A Review on Their Role and Potential Applications

Brain metastases (BM) are a frequent complication in patients with advanced stages of cancer, associated with impairment of the neurological function, quality of life, prognosis, and survival. BM treatment consists of a combination of the available cancer therapies, such as surgery, radiotherapy, chemotherapy, immunotherapy and targeted therapies. Even so, cancer patients with BM are still linked to poor prognosis, with overall survival being reported as 12 months or less. Intercellular communication has a pivotal role in the development of metastases, therefore, it has been extensively studied not only to better understand the metastization process, but also to further develop new therapeutic strategies. Exosomes have emerged as key players in intercellular communication being potential therapeutic targets, drug delivery systems (DDS) or biomarkers. In this Review, we focus on the role of these extracellular vesicles (EVs) in BM formation and their promising application in the development of new BM therapeutic strategies.

A Novel Silicon Platform for Selective Isolation, Quantification, and Molecular Analysis of Small Extracellular Vesicles

Introduction

Small extracellular vesicles (sEVs), thanks to their cargo, are involved in cellular communication and play important roles in cell proliferation, growth, differentiation, apoptosis, stemness and embryo development. Their contribution to human pathology has been widely demonstrated and they are emerging as strategic biomarkers of cancer, neurodegenerative and cardiovascular diseases, and as potential targets for therapeutic intervention. However, the use of sEVs for medical applications is still limited due to the selectivity and sensitivity limits of the commonly applied approaches.

Methods

Novel sensing solutions based on nanomaterials are arising as strategic tools able to surpass traditional sensor limits. Among these, Si nanowires (Si NWs), realized with cost-effective industrially compatible metal-assisted chemical etching, are perfect candidates for sEV detection.

Results

In this paper, the realization of a selective sensor able to isolate, concentrate and quantify specific vesicle populations, from minimal volumes of biofluid, is presented. In particular, this Si NW platform has a detection limit of about 2×10⁵ sEVs/mL and was tested with follicular fluid and blastocoel samples. Moreover, the possibility to detach the selectively isolated sEVs allowing further analyses with other approaches was demonstrated by SEM analysis and several PCRs performed on the RNA content of the detached sEVs.

Discussion

This platform overcomes the limit of detection of traditional methods and, most importantly, preserves the biological content of sEVs, opening the route toward a reliable liquid biopsy analysis.

Extracellular vesicles: the key for precision medicine in glioblastoma

Glioblastoma (GBM) represents the most aggressive and lethal disease of the central nervous system. Diagnosis is delayed following the occurrence of symptoms, and treatment is based on standardized approaches that are unable to cope with its heterogeneity, mutability, and invasiveness. The follow-up of patients relies on burdensome schedules for magnetic resonance imaging (MRI). However, to personalize treatment, biomarkers and liquid biopsy still represent unmet clinical needs. Extracellular vesicles (EVs) may be the key to revolutionize the entire process of care for patients with GBM. EVs can be collected noninvasively (eg, blood) and impressively possess multilayered information, which is constituted by their concentration and molecular cargo. EV-based liquid biopsy may facilitate GBM diagnosis and enable the implementation of personalized treatment, resulting in customized care for each patient and for each analyzed time point of the disease, thereby tackling the distinctive heterogeneity and mutability of GBM that confounds effective treatment. Herein, we discuss the limitations of current GBM treatment options and the rationale behind the need for personalized care. We also review the evidence supporting GBM-associated EVs as a promising tool capable of fulfilling the still unmet clinical need for effective and timely personalized care of patients with GBM.

Biosensor-based assay of exosome biomarker for early diagnosis of cancer

Cancer imposes a severe threat to people's health and lives, thus pressing a huge medical and economic burden on individuals and communities. Therefore, early diagnosis of cancer is indispensable in the timely prevention and effective treatment for patients. Exosome has recently become an attractive cancer biomarker in noninvasive early diagnosis because of the unique physiology and pathology functions, which reflects remarkable information regarding the cancer microenvironment, and plays an important role in the occurrence and evolution of cancer. Meanwhile, biosensors have gained great attention for the detection of exosomes due to their superior properties, such as convenient operation, real-time readout, high sensitivity, and remarkable specificity, suggesting promising biomedical applications in the early diagnosis of cancer. In this review, the latest advances of biosensors regarding the assay of exosomes were summarized, and the superiorities of exosomes as markers for the early diagnosis of cancer were evaluated. Moreover, the recent challenges and further opportunities of developing effective biosensors for the early diagnosis of cancer were discussed.

Towards nanovesicle-based disease diagnostics: a rapid single-step exosome assay within one hour through in situ immunomagnetic extraction and nanophotonic label-free detection

Exosomes have been considered as high-quality biomarkers for disease diagnosis, as they are secreted by cells into extracellular environments as nanovesicles with rich and unique molecular information, and can be isolated and enriched from clinical samples. However, most existing exosome assays, to date, require time-consuming isolation and purification procedures; the detection specificity and sensitivity are also in need of improvement for the realization of exosome-based disease diagnostics. This paper reports a unique exosome assay technology that enables completing both magnetic nanoparticle (MNP)-based exosome extraction and high-sensitivity photonic crystal (PC)-based label-free exosome detection in a single miniature vessel within one hour, while providing an improved sensitivity and selectivity. High specificity of the assay to membrane antigens is realized by functionalizing both the MNPs and the PC with specific antibodies. A low limit of detection on the order of 10⁷ exosome particles per milliliter (volume) is achieved because the conjugated MNP-exosome nanocomplexes offer a larger index change on the PC surface, compared to the exosomes alone without using MNPs. Briefly, the single-step exosome assay involves (i) forming specific MNP-exosome nanocomplexes to enrich exosomes from complex samples directly on the PC surface at the bottom of the vessel, with a >500 enrichment factor, and (ii) subsequently, performing in situ quantification of the nanocomplexes using the PC biosensor. The present exosome assay method is validated in analyzing multiple membrane proteins of exosomes derived from murine macrophage cells with high selectivity and sensitivity, while requiring only about one hour. This assay technology will provide great potential for exosome-based disease diagnostics.

[Microfluidic strategies for separation and analysis of circulating exosomes]

外泌体是一类由细胞分泌的含有脂质、蛋白、核酸等多种物质的纳米级囊泡,主要参与细胞间的物质交换及信息传导,与多种疾病的发生发展密切相关。对外泌体进行深入研究,理解其生物学功能,对疾病诊断与治疗具有重要意义。由于外泌体尺寸较小且密度和体液接近,想要对复杂生物样本中的外泌体进行分离与分析十分困难。传统的外泌体分离方法如超速离心、超滤等大都需要借助大型仪器设备,且耗时长、操作复杂。因此迫切需要开发高效、便捷的外泌体分离检测手段。微流控技术因其微型化、高通量、可集成等特点,为外泌体的分离分析提供了一个新的平台。该文主要对近年来微流控技术在外泌体分离分析相关领域的研究进展进行了综述。重点从外泌体物理特性和生化特性两个角度出发,介绍了微流控芯片技术用于外泌体分离领域的主要原理、策略和方法。此外,还介绍了微流控技术与荧光、电化学传感、表面等离子体共振等多模态检测方法结合,实现外泌体一体化分析的新进展。最后,该文分析了目前微流控技术用于外泌体分离检测存在的挑战,并对其发展趋势和前景进行了展望。随着微流控外泌体分离分析装置的不断微型化、集成化、自动化,微流控芯片技术将在外泌体分离、生化检测、机制研究等方面将发挥越来越重要的作用。

Advances in microfluidic extracellular vesicle analysis for cancer diagnostics

Extracellular vesicles (EVs) secreted by cells into the bloodstream and other bodily fluids, including exosomes, have been demonstrated to be a class of significant messengers that mediate intercellular communications. Tumor-derived extracellular vesicles are enriched in a selective set of biomolecules from original cells, including proteins, nucleic acids, and lipids, and thus offer a new perspective of liquid biopsy for cancer diagnosis and therapeutic monitoring. Owing to the heterogeneity of their biogenesis, physical properties, and molecular constituents, isolation and molecular characterization of EVs remain highly challenging. Microfluidics provides a disruptive platform for EV isolation and analysis owing to its inherent advantages to promote the development of new molecular and cellular sensing systems with improved sensitivity, specificity, spatial and temporal resolution, and throughput. This review summarizes the state-of-the-art advances in the development of microfluidic principles and devices for EV isolation and biophysical or biochemical characterization, in comparison to the conventional counterparts. We will also survey the progress in adapting the new microfluidic techniques to assess the emerging EV-associated biomarkers, mostly focused on proteins and nucleic acids, for clinical diagnosis and prognosis of cancer. Lastly, we will discuss the current challenges in the field of EV research and our outlook on future development of enabling microfluidic platforms for EV-based liquid biopsy.

Zebrafish as a preclinical model for Extracellular Vesicle-based therapeutic development

Extracellular Vesicles (EVs) are released during various pathophysiological processes and reflect the state of their cell of origin. Once released, they can propagate through biological fluids, target cells, deliver their content and elicit functional responses. These specific features would allow their harnessing as biomarkers, drug nano-vehicles and therapeutic intrinsic modulators. However, the further development of their potential therapeutic application is hampered by the lack of knowledge about how EVs behave in vivo. Recent advances in the field of imaging EVs in vivo now allow live-tracking of endogenous and exogenous EV in various model organisms at high spatiotemporal resolution to define their distribution, half-life and fate. This review highlights current imaging tools available to image EVs in vivo and how live imaging especially in the zebrafish embryo can bring further insights into the characterization of EVs dynamics, biodistribution and functions to potentiate their development for therapeutic applications.

Collaborative Equilibrium Coupling of Catalytic DNA Nanostructures Enables Programmable Detection of SARS-CoV-2

Accessible and adaptable nucleic acid diagnostics remains a critical challenge in managing the evolving COVID-19 pandemic. Here, an integrated molecular nanotechnology that enables direct and programmable detection of SARS-CoV-2 RNA targets in native patient specimens is reported. Termed synergistic coupling of responsive equilibrium in enzymatic network (SCREEN), the technology leverages tunable, catalytic molecular nanostructures to establish an interconnected, collaborative architecture. SCREEN mimics the extraordinary organization and functionality of cellular signaling cascades. Through programmable enzyme-DNA nanostructures, SCREEN activates upon interaction with different RNA targets to initiate multi-enzyme catalysis; through system-wide favorable equilibrium shifting, SCREEN directly transduces a single target binding into an amplified electrical signal. To establish collaborative equilibrium coupling in the architecture, a computational model that simulates all reactions to predict overall performance and optimize assay configuration is developed. The developed platform achieves direct and sensitive RNA detection (approaching single-copy detection), fast response (assay reaction is completed within 30 min at room temperature), and robust programmability (across different genetic loci of SARS-CoV-2). When clinically evaluated, the technology demonstrates robust and direct detection in clinical swab lysates to accurately diagnose COVID-19 patients.

Regulatory role of long non coding RNAs (lncRNAs) in neurological disorders: From novel biomarkers to promising therapeutic strategies

Long non coding RNAs (lncRNAs) are non-protein or low-protein coding transcripts that contain more than 200 nucleotides. They representing a large share of the cell's transcriptional output, demonstrate functional attributes viz. tissue-specific expression, determination of cell fate, controlled expression, RNA processing and editing, dosage compensation, genomic imprinting, conserved evolutionary traits etc. These long non coding variants are well associated with pathogenicity of various diseases including the neurological disorders like Alzheimer's disease, schizophrenia, Huntington's disease, Parkinson's disease etc. Neurological disorders are widespread and there knowing the underlying mechanisms become crucial. The lncRNAs take part in the pathogenesis by a plethora of mechanisms like decoy, scaffold, mi-RNA sequestrator, histone modifiers and in transcriptional interference. Detailed knowledge of the role of lncRNAs can help to use them further as novel biomarkers for therapeutic aspects. Here, in this review we discuss regulation and functional roles of lncRNAs in eight neurological diseases and psychiatric disorders, and the mechanisms by which they act. With these, we try to establish their roles as potential markers and viable diagnostic tools in these disorders.

The role of extracellular vesicles in the physiological and pathological regulation of the blood-brain barrier

Extracellular vesicles (EVs) are a subclass of biological nanoparticles secreted by most cell types. Once secreted, EVs can travel long distances to deliver their content to target cells thereby playing a key role in cell-to-cell communication and supporting both physiological and pathological processes. In recent years, the functional versatility of EVs has come to be more widely appreciated. Their heterogeneous structure encloses solubilized bioactive cargoes including proteins and nucleic acids. EVs mirror the secreting cell in composition therefore representing a novel source of diagnostic and prognostic biomarkers. Moreover, due to their unique structure, EVs constitute a promising class of biocompatible nanovehicles for drug delivery as well. Importantly, and of burgeoning interest, is the fact that EVs have the intrinsic ability to breach biological barriers including the complex blood-brain barrier (BBB), whose restrictive nature represents a significant therapeutic challenge. EVs have been shown to contribute to the progression of a variety of brain diseases including metastatic brain cancer, neurodegenerative diseases, and acute pathologies including infections and ischemia. In this review, the role of EVs in the maintenance and regulation of the BBB under normal physiological and pathologic conditions are discussed. Applications of EVs as therapeutic and diagnostic tools in the treatment of diseases that affect the central nervous system are presented as are limitations hindering their broad translation and potential solutions to resolve them.

Single-Cell Cloning of Breast Cancer Cells Secreting Specific Subsets of Extracellular Vesicles

Simple Summary

Extracellular vesicles (EVs) are a pivotal mechanism for long-distance intercellular communication and facilitate the stable transport of biological information. Conventional methods for profiling EVs are focused on the biological cargo obtained from large populations of cells and cannot map the secretion of specific subsets of EVs onto their cell of origin. We developed a high-throughput single-cell cloning method that can identify the kinetics of secretion of specific subsets of EVs. With the aid of this methodology, we illustrate that secretion of specific subsets of EVs can be an inheritable property of cancer cells. Our single-cell methodology enables the direct integration of EV secretion with multiple cellular functions and can enable new insights into cell and disease biology.

Abstract

Extracellular vesicles (EVs) mediate communication in health and disease. Conventional assays are limited in profiling EVs secreted from large populations of cells and cannot map EV secretion onto individual cells and their functional profiles. We developed a high-throughput single-cell technique that enabled the mapping of dynamics of EV secretion. By utilizing breast cancer cell lines, we established that EV secretion is heterogeneous at the single-cell level and that non-metastatic cancer cells can secrete specific subsets of EVs. Single-cell RNA sequencing confirmed that pathways related to EV secretion were enriched in the non-metastatic cells compared with metastatic cells. We established isogenic clonal cell lines from non-metastatic cells with differing propensities for CD81⁺CD63⁺EV secretion and showed for the first time that specificity in EV secretion is an inheritable property preserved during cell division. Combined in vitro and animal studies with these cell lines suggested that CD81⁺CD63⁺EV secretion can impede tumor formation. In human non-metastatic breast tumors, tumors enriched in signatures of CD81⁺CD63⁺EV have a better prognosis, higher immune cytolytic activity, and enrichment of pro-inflammatory macrophages compared with tumors with low CD81⁺CD63⁺EVs signatures. Our single-cell methodology enables the direct integration of EV secretion with multiple cellular functions and enables new insights into cell/disease biology.

A systematic review of extracellular vesicles as non-invasive biomarkers in glioma diagnosis, prognosis, and treatment response monitoring

The present systematic review was done to investigate the possible application of Extracellular vesicles (EVs) in the diagnosis, prognosis, and treatment response monitoring of gliomas using available literature to wrap up the final applicable conclusion in this regard. we searched PubMed/MEDLINE, Scopus, and ISI Web of Science databases. Authors evaluated the quality of the included studies by the QUADAS-2 tool. In total, 2037 published datasets were retrieved through systematic search. Upon screening for eligibility, 35 datasets were determined as eligible. Exosome was the EV-subtype described in the majority of studies, and most datasets used serum as the primary EVs isolation source. EVs isolation was primarily conducted by ultracentrifugation. 31 datasets reported that EVs hold considerable potential for being used in diagnostics, with the majority reporting different types of miRNAs as biomarkers. Besides, 8 datasets reported that EVs could be a potential source of prognostic biomarkers. And finally, 3 datasets reported that EVs might be a reliable strategy for monitoring therapy response in glioma patients. According to the findings of the current systematic review, it seems that miR-301, miR-21, and HOTAIR had the highest diagnostic accuracy. However, heterogeneous and limited evidence regarding prognosis and treatment response monitoring precludes us from drawing a practical conclusion regarding EVs.

Extracellular Vesicle Separation Techniques Impact Results from Human Blood Samples: Considerations for Diagnostic Applications

Extracellular vesicles (EVs) are reminiscent of their cell of origin and thus represent a valuable source of biomarkers. However, for EVs to be used as biomarkers in clinical practice, simple, comparable, and reproducible analytical methods must be applied. Although progress is being made in EV separation methods for human biofluids, the implementation of EV assays for clinical diagnosis and common guidelines are still lacking. We conducted a comprehensive analysis of established EV separation techniques from human serum and plasma, including ultracentrifugation and size exclusion chromatography (SEC), followed by concentration using (a) ultracentrifugation, (b) ultrafiltration, or (c) precipitation, and immunoaffinity isolation. We analyzed the size, number, protein, and miRNA content of the obtained EVs and assessed the functional delivery of EV cargo. Our results demonstrate that all methods led to an adequate yield of small EVs. While no significant difference in miRNA content was observed for the different separation methods, ultracentrifugation was best for subsequent flow cytometry analysis. Immunoaffinity isolation is not suitable for subsequent protein analyses. SEC + ultracentrifugation showed the best functional delivery of EV cargo. In summary, combining SEC with ultracentrifugation gives the highest yield of pure and functional EVs and allows reliable analysis of both protein and miRNA contents. We propose this combination as the preferred EV isolation method for biomarker studies from human serum or plasma.

Isolation and analysis methods of extracellular vesicles (EVs)

Extracellular vesicles (EVs) have been recognized as an evolving biomarker within the liquid biopsy family. While carrying both host cell proteins and different types of RNAs, EVs are also present in sufficient quantities in biological samples to be tested using many molecular analysis platforms to interrogate their content. However, because EVs in biological samples are comprised of both disease and non-disease related EVs, enrichment is often required to remove potential interferences from the downstream molecular assay. Most benchtop isolation/enrichment methods require > milliliter levels of sample and can cause varying degrees of damage to the EVs. In addition, some of the common EV benchtop isolation methods do not sort the diseased from the non-diseased related EVs. Simultaneously, the detection of the overall concentration and size distribution of the EVs is highly dependent on techniques such as electron microscopy and Nanoparticle Tracking Analysis, which can include unexpected variations and biases as well as complexity in the analysis. This review discusses the importance of EVs as a biomarker secured from a liquid biopsy and covers some of the traditional and non-traditional, including microfluidics and resistive pulse sensing, technologies for EV isolation and detection, respectively.

Engineered exosomes: desirable target-tracking characteristics for cerebrovascular and neurodegenerative disease therapies

As extracellular vesicles secreted by cells, exosomes are intercellular signalosomes for cell communication and pharmacological effectors. Because of their special properties, including low toxicity and immunogenicity, biodegradability, ability to encapsulate endogenous biologically active molecules and cross the blood-brain barrier (BBB), exosomes have great therapeutic potential in cerebrovascular and neurodegenerative diseases. However, the poor targeting ability of natural exosomes greatly reduces the therapeutic effect. Using engineering technology, exosomes can obtain active targeting ability to accumulate in specific cell types and tissues by attaching targeting units to the membrane surface or loading them into cavities. In this review, we outline the improved targeting functions of bioengineered exosomes, tracing and imaging techniques, administration methods, internalization in the BBB, and therapeutic effects of exosomes in cerebrovascular and neurodegenerative diseases and further evaluate the clinical opportunities and challenges in this research field.

Extracellular Vesicles in neural cell interaction and CNS homeostasis

Central nervous system (CNS) homeostasis critically depends on the interaction between neurons and glia cells. Extracellular vesicles (EVs) recently emerged as versatile messengers in CNS cell communication. EVs are released by neurons and glia in activity-dependent manner and address multiple target cells within and outside the nervous system. Here, we summarize the recent advances in understanding the physiological roles of EVs in the nervous system and their ability to deliver signals across the CNS barriers. In addition to the disposal of cellular components via EVs and clearance by phagocytic cells, EVs are involved in plasticity-associated processes, mediate trophic support and neuroprotection, promote axonal maintenance, and modulate neuroinflammation. While individual functional components of the EV cargo are becoming progressively identified, the role of neural EVs as compound multimodal signaling entities remains to be elucidated. Novel transgenic models and imaging technologies allow EV tracking in vivo and provide further insight into EV targeting and their mode of action. Overall, EVs represent key players in the maintenance of CNS homeostasis essential for the lifelong performance of neural networks and thus provide a wide spectrum of biomedical applications.

Strategies to Enhance Extracellular Vesicle Production

Extracellular vesicles (EVs) are sub-micrometer lipid vesicles secreted from parental cells with their information such as DNA, RNA, and proteins. EVs can deliver their cargo to recipient cells and regulate the signaling pathway of the recipient cells to determine their destiny. Depending on the cargo of EVs, the recipient cells can be changed into abnormal state or be relieved from diseases. Therefore, EVs has been spotlighted as emerging therapeutics in biomedical research. However, slow EV secretion rate is the major limitation for the clinical applications of EVs. EV secretion is highly environmental dependent and can be regulated by various stimulants such as chemicals, oxygen levels, pH, radiation, starvation, and culture methods. To overcome the limitation of low productivity of EVs, EV stimulation methods have been widely studied and applied to massive EV productions. Another strategy is the synthesis of artificial EVs from cells by physical methods such as nitrogen cavitation, extrusion via porous membrane, and sonication. These physical methods disrupt cellular membrane and reassemble the membrane to lipid vesicles containing proteins or drugs. In this review, we will focus on how EV generation can be enhanced and recent advances in large scale EV generation strategies.

Membrane Feature-Inspired Profiling of Extracellular Vesicles for Pancreatic Cancer Diagnosis

Extracellular vesicles (EVs) have recently emerged as a promising tumor biomarker, and EV phenotyping offers many benefits for cancer diagnosis. However, the practicality of EV assays remains a challenge due to macromolecule disturbances, biomarker heterogeneities, and EV abundance limitations. Here, we demonstrate a membrane-based biosensor for precise and sensitive EV identification. The sensor synergistically integrates EV capture and detection by virtue of EV membrane features (membrane protein and lipid bilayer), comprising antibody-conjugated magnetic beads (AbMBs) and duplex-specific nuclease (DSN)-mediated amplification cycles. Bivalent cholesterol (biChol)-modified RNA-DNA duplexes are designed to insert into the EV membrane, transforming EV signals into RNA signals and initiating the signal amplification. The membrane-based signal production pattern eliminates protein interference. By employing four antibodies specific to PCa-related membrane proteins, the AbMB-biChol platform enables the successful differentiation and monitoring of PCa-related EVs and distinguishes PCa patients from healthy donors with improved efficacy, exhibiting superior efficiency over the analyses based on clinically used biomarker CA19-9 and PCa-related proteins. As such, the developed system has great potential for clinical PCa diagnosis.

An integrated magneto-electrochemical device for the rapid profiling of tumour extracellular vesicles from blood plasma

Assays for cancer diagnosis via the analysis of biomarkers on circulating extracellular vesicles (EVs) typically have lengthy sample workups, limited throughput or insufficient sensitivity, or do not use clinically validated biomarkers. Here we report the development and performance of a 96-well assay that integrates the enrichment of EVs by antibody-coated magnetic beads and the electrochemical detection, in less than one hour of total assay time, of EV-bound proteins after enzymatic amplification. By using the assay with a combination of antibodies for clinically relevant tumour biomarkers (EGFR, EpCAM, CD24 and GPA33) of colorectal cancer (CRC), we classified plasma samples from 102 patients with CRC and 40 non-CRC controls with accuracies of more than 96%, prospectively assessed a cohort of 90 patients, for whom the burden of tumour EVs was predictive of five-year disease-free survival, and longitudinally analysed plasma from 11 patients, for whom the EV burden declined after surgery and increased on relapse. Rapid assays for the detection of combinations of tumour biomarkers in plasma EVs may aid cancer detection and patient monitoring.