Isolation of exosomes from whole blood by a new microfluidic device: proof of concept application in the diagnosis and monitoring of pancreatic cancer

Single-cell Organelle Extraction with Cellular Indexing

Bulk methods to fractionate organelles lack the resolution to capture single-cell heterogeneity. While microfluidic approaches attempt to fractionate organelles at the cellular level, they fail to map each organelle back to its cell of origin-crucial for multiomics applications. To address this, we developed VacTrap, a high-throughput microfluidic device for isolating and spatially indexing single nuclei from mammalian cells. VacTrap consists of three aligned layers: (1) a Bis-gel microwells layer with a 'trapdoors' (BAC-gel) base, fabricated atop a through-hole glass slide; (2) a PDMS microwell layer to receive transferred nuclei; and (3) a vacuum manifold. VacTrap operation begins with cell lysis using DDF to release intact nuclei into the Bis-gel microwells, while cytoplasmic proteins are electrophoresed into the Bis-gel. Upon exposure to DTT and vacuum force, the trapdoors open, allowing nuclei to transfer to the PDMS microwells. VacTrap dissolves the trapdoors within 3-5 minutes and achieve synchronized nuclei transfer with 98% efficiency across 80% of trapdoors in a 256-microwell array, surpassing the <1% efficiency of passive transfer without vacuum. Morphology analysis confirmed preservation of organelle integrity throughout VacTrap operation. By enabling spatial indexing of nuclei back to their original cell, VacTrap provides a robust, high-throughput tool for single-cell multiomics applications.

Advancements in Exosome Proteins for Breast Cancer Diagnosis and Detection: With a Focus on Nanotechnology

Breast cancer, a leading cause of mortality among women, has been recognized as requiring improved diagnostic methods. Exosome proteins, found in small extracellular vesicles, have emerged as a promising solution, reflecting the state of their cell of origin and playing key roles in cancer progression. This review examines their potential in breast cancer diagnosis, discussing advanced isolation and characterization techniques such as ultracentrifugation and microfluidic-based approaches. Various detection methods-including electrochemical, nano-based, optical, and machine learning platforms-were evaluated for their high sensitivity, specificity, and non-invasive capabilities. Electrochemical methods were used to identify unique protein signatures for rapid, cost-effective diagnosis, while machine learning enhanced the classification of exosome proteins. Nano-based techniques leveraged nanomaterials to detect low-abundance proteins, and optical methods offered real-time, label-free monitoring. Despite their promise, challenges in standardizing protocols and integrating these diagnostics into clinical practice remain. Future directions include technological advancements, personalized medicine, and exploring the therapeutic potential of exosome proteins.

Basic Guide for Approaching Drug Delivery with Extracellular Vesicles

Extracellular vesicles (EVs) are natural carriers of biomolecules that play a crucial role in cell-to-cell communication and tissue homeostasis under normal and pathological conditions, including inflammatory diseases and cancer. Since the discovery of the pro-regenerative and immune-modulating properties of EVs, EV-based therapeutics have entered clinical trials for conditions such as myocardial infarction and autoimmune diseases, among others. Due to their unique advantages-such as superior bioavailability, substantial packaging capacity, and the ability to traverse biological barriers-EVs are regarded as a promising platform for targeted drug delivery. However, achieving a sufficient accumulation of therapeutic agents at the target site necessitates a larger quantity of EVs per dose compared to using EVs as standalone drugs. This challenge can be addressed by administering larger doses of EVs, increasing the drug dosage per administration, or enhancing the selective accumulation of EVs at target cells. In this review, we will discuss methods to improve the isolation and purification of EVs, approaches to enhance cargo packaging-including proteins, RNAs, and small-molecule drugs-and technologies for displaying targeting ligands on the surface of EVs to facilitate improved targeting. Ultimately, this guide can be applied to the development of novel classes of EV-based therapeutics and to overcoming existing technological challenges.

Microfluidic systems for modeling digestive cancer: a review of recent progress

Purpose. This review aims to highlight current improvements in microfluidic devices designed for digestive cancer simulation. The review emphasizes the use of multicellular 3D tissue engineering models to understand the complicated biology of the tumor microenvironment (TME) and cancer progression. The purpose is to develop oncology research and improve digestive cancer patients' lives.Methods. This review analyzes recent research on microfluidic devices for mimicking digestive cancer. It uses tissue-engineered microfluidic devices, notably organs on a chip (OOC), to simulate human organ function in the lab. Cell cultivation on modern three-dimensional hydrogel platforms allows precise geometry, biological components, and physiological qualities. The review analyzes novel methodologies, key findings, and technical progress to explain this field's advances.Results. This study discusses current advances in microfluidic devices for mimicking digestive cancer. Micro physiological systems with multicellular 3D tissue engineering models are emphasized. These systems capture complex biochemical gradients, niche variables, and dynamic cell-cell interactions in the tumor microenvironment (TME). These models reveal stomach cancer biology and progression by duplicating the TME. Recent discoveries and technology advances have improved our understanding of gut cancer biology, as shown in the review.Conclusion. Microfluidic systems play a crucial role in modeling digestive cancer and furthering oncology research. These platforms could transform drug development and treatment by revealing the complex biology of the tumor microenvironment and cancer progression. The review provides a complete summary of recent advances and suggests future research for field professionals. The review's major goal is to further medical research and improve digestive cancer patients' lives.

Recent progress in engineered extracellular vesicles and their biomedical applications

AIMS

To present the recent update on the isolation, engineering techniques for extracellular vesicles, limitations associated with different isolation techniques, different biomedical applications, and challenges of engineered extracellular vesicles for the benefit of researchers from academic, industry, etc. MATERIALS AND METHODS: Peer-reviewed articles from most recognized journals were collected, and presented information was analyzed to discuss collection, chemical, electroporation, cellular, and membrane surface engineering to design extracellular vesicles for various therapeutic applications. In addition, we present the applications and limitations of techniques for the collection of extracellular vesicles.

KEY FINDINGS

There is a need for isolation techniques with the gold standard. However, advanced extracellular vesicle isolation techniques showed improved recovery, and purity of extracellular vesicles. Tumor therapy is a major part of the therapy section that illustrates the role of engineered extracellular vesicles in synergetic therapy such as phototherapy, theragnostic, and delivery of genetic materials. In addition, extracellular vesicles have shown their potential in the treatment of retinal disorders, neurodegenerative disease, tuberculosis, osteoporosis, inflammatory bowel disease, vaccine production, and wound healing.

SIGNIFICANCE

Engineered extracellular vesicles can deliver cargo to the specific cells, elicit an immune response and could be used for the development of the vaccines in the future. However, the progress is at the initial stage. Overall, this review will provide a comprehensive understanding and could serve as a reference for researchers in the clinical translation of engineered extracellular vesicles in different biomedical fields.

The Exosome-Mediated Bone Regeneration: An Advanced Horizon Toward the Isolation, Engineering, Carrying Modalities, and Mechanisms

Exosomes, nanoparticles secreted by various cells, composed of a bilayer lipid membrane, and containing bioactive substances such as proteins, nucleic acids, metabolites, etc., have been intensively investigated in tissue engineering owing to their high biocompatibility and versatile biofunction. However, there is still a lack of a high-quality review on bone defect regeneration potentiated by exosomes. In this review, the biogenesis and isolation methods of exosomes are first introduced. More importantly, the engineered exosomes of the current state of knowledge are discussed intensively in this review. Afterward, the biomaterial carriers of exosomes and the mechanisms of bone repair elucidated by compelling evidence are presented. Thus, future perspectives and concerns are revealed to help devise advanced modalities based on exosomes to overcome the challenges of bone regeneration. It is totally believed this review will attract special attention from clinicians and provide promising ideas for their future works.

Recent research on material-based methods for isolation of extracellular vesicles

Extracellular vesicles (EVs) are nanoparticles secreted by cells with a closed phospholipid bilayer structure, which can participate in various physiological and pathological processes and have significant clinical value in disease diagnosis, targeted therapy and prognosis assessment. EV isolation methods currently include differential ultracentrifugation, ultrafiltration, size exclusion chromatography, immunoaffinity, polymer co-precipitation and microfluidics. In addition, material-based biochemical or biophysical approaches relying on intrinsic properties of the material or its surface-modified functionalized monomers, demonstrated unique advantages in the efficient isolation of EVs. In order to provide new ideas for the subsequent development of material-based EV isolation methods, this review will focus on the principle, research status and application prospects of material-based EV isolation methods based on different material carriers and functional monomers.

Therapeutic Potential of Bovine Milk-Derived Extracellular Vesicles

Milk is a fundamental component of the human diet, owing to its substantial nutritional content. In addition, milk contains nanoparticles called extracellular vesicles (EVs), which have indicated their potential beneficial roles such as cell-to-cell communication, disease biomarkers, and therapeutics agents. Amidst other types of EVs, milk EVs (MEVs) have their significance due to their high abundance, easy access, and stability in harsh environmental conditions, such as low pH in the gut. There have been plenty of studies conducted to evaluate the therapeutic potential of bovine MEVs over the past few years, and attention has been given to their engineering for drug delivery and targeted therapy. However, there is a gap between the experimental findings available and clinical trials due to the many challenges related to EV isolation, cargo, and the uniformity of the material. This review aims to provide a comprehensive comparison of various techniques for the isolation of MEVs and offers a summary of the therapeutic potential of bovine MEVs described over the last decade, analyzing potential challenges and further applications. Although a number of aspects still need to be further elucidated, the available data point to the role of MEVs as a potential candidate with therapeutics potential, and the supplementation of MEVs would pave the way to understanding their in-depth effects.

An overview of challenges associated with exosomal miRNA isolation toward liquid biopsy-based ovarian cancer detection

As one of the deadliest gynaecological cancers, ovarian cancer has been on the list. With lesser-known symptoms and lack of an accurate detection method, it is still difficult to catch it early. In terms of both the diagnosis and outlook for cancer, liquid biopsy has come a long way with significant advancements. Exosomes, extracellular components commonly shed by cancerous cells, are nucleic acid-rich particles floating in almost all body fluids and hold enormous promise, leading to minimallyinvasive molecular diagnostics. They have been shown as potential biomarkers in liquid biopsy, being implicated in tumour growth and metastasis. In order to address the drawbacks of ovarian cancer tumor heterogeneity, a liquid biopsy-based approach is being investigated by detecting cell-free nucleic acids, particularly non-coding RNAs, having the advantage of being less invasive and more prominent in nature. microRNAs are known to actively contribute to cancer development and their existence inside exosomes has also been made quite apparent which can be leveraged to diagnose and treat the disease. Extraction of miRNAs and exosomes is an arduous execution, and while other approaches have been investigated, none have produced results that are as encouraging due to limits in time commitment, yield, and, most significantly, damage to the exosomal structure resulting discrepancies in miRNA-based expression profiling for disease diagnosis. We have briefly outlined and reviewed the difficulties with exosome isolation techniques and the need for their standardization. The several widely used procedures and their drawbacks in terms of the exosomal purity they may produce have also been outlined.

High-Throughput Microfluidic Extraction of Platelet-free Plasma for MicroRNA and Extracellular Vesicle Analysis

Cell-free RNAs and extracellular vesicles (EVs) are valuable biomarkers in liquid biopsies, but they are prone to preanalytical variabilities such as nonstandardized centrifugation or ex vivo blood degradation. Herein, we report a high-throughput and label-free inertial microfluidic device (ExoArc) for isolation of platelet-free plasma from blood for RNA and EV analysis. Unlike conventional inertial microfluidic devices widely used for cell sorting, a submicrometer size cutoff (500 nm) was achieved which completely removed all leukocytes, RBCs, platelets, and cellular debris based on differential lateral migration induced by Dean vortices. The single-step operation also reduced platelet-associated miRNAs (∼2-fold) compared to centrifugation. We clinically validated ExoArc for plasma miRNA profiling (39 samples) and identified a 7-miRNA panel that detects non-small cell lung cancer with ∼90% sensitivity. ExoArc was also coupled with size exclusion chromatography (SEC) to isolate EVs within 50 min with ∼10-fold higher yield than ultracentrifugation. As a proof-of-concept for EV-based transcriptomics analysis, we performed miRNA analysis in healthy and type 2 diabetes mellitus (T2DM) subjects (n = 3 per group) by coupling ExoArc and ExoArc+SEC with quantitative polymerase chain reaction (RT-qPCR) assay. Among 293 miRNAs detected, plasmas and EVs showed distinct differentially expressed miRNAs in T2DM subjects. We further demonstrated automated in-line EV sorting from low volume culture media for continuous EV monitoring. Overall, the developed ExoArc offers a convenient centrifugation-free workflow to automate plasma and EV isolation for point-of-care diagnostics and quality control in EV manufacturing.

Exosome subpopulations: The isolation and the functions in diseases

Exosomes are nanoscale extracellular vesicles secreted by cells. Exosomes mediate intercellular communication by releasing their bioactive contents (e.g., DNAs, RNAs, lipids, proteins, and metabolites). The components of exosomes are regulated by the producing cells of exosomes. Due to their diverse origins, exosomes are highly heterogeneous in size, content, and function. Depending on these characteristics, exosomes can be divided into multiple subpopulations which have different functions. Efficient enrichment of specific subpopulations of exosomes helps to investigate their biological functions. Accordingly, numerous techniques have been developed to isolate specific subpopulations of exosomes. This review systematically introduces emerging new technologies for the isolation of different exosome subpopulations and summarizes the critical role of specific exosome subpopulations in diseases, especially in tumor occurrence and progression.

Engineering of Cell Derived-Nanovesicle as an Alternative to Exosome Therapy

BACKGROUND

Exosomes, nano-sized vesicles ranging between 30 and 150 nm secreted by human cells, play a pivotal role in long-range intercellular communication and have attracted significant attention in the field of regenerative medicine. Nevertheless, their limited productivity and cost-effectiveness pose challenges for clinical applications. These issues have recently been addressed by cell-derived nanovesicles (CDNs), which are physically synthesized exosome-mimetic nanovesicles from parent cells, as a promising alternative to exosomes. CDNs exhibit structural, physical, and biological properties similar to exosomes, containing intracellular protein and genetic components encapsulated by the cell plasma membrane. These characteristics allow CDNs to be used as regenerative medicine and therapeutics on their own, or as a drug delivery system.

METHODS

The paper reviews diverse methods for CDN synthesis, current analysis techniques, and presents engineering strategies to improve lesion targeting efficiency and/or therapeutic efficacy.

RESULTS

CDNs, with their properties similar to those of exosomes, offer a cost-effective and highly productive alternative due to their non-living biomaterial nature, nano-size, and readiness for use, allowing them to overcome several limitations of conventional cell therapy methods.

CONCLUSION

Ongoing research and enhancement of CDNs engineering, along with comprehensive safety assessments and stability analysis, exhibit vast potential to advance regenerative medicine by enabling the development of efficient therapeutic interventions.

Emerging Microfluidic Tools for Simultaneous Exosomes and Cargo Biosensing in Liquid Biopsy: New Integrated Miniaturized FFF-Assisted Approach for Colon Cancer Diagnosis

The early-stage diagnosis of cancer is a crucial clinical need. The inadequacies of surgery tissue biopsy have prompted a transition to a less invasive profiling of molecular biomarkers from biofluids, known as liquid biopsy. Exosomes are phospholipid bilayer vesicles present in many biofluids with a biologically active cargo, being responsible for cell-to-cell communication in biological systems. An increase in their excretion and changes in their cargo are potential diagnostic biomarkers for an array of diseases, including cancer, and they constitute a promising analyte for liquid biopsy. The number of exosomes released, the morphological properties, the membrane composition, and their content are highly related to the physiological and pathological states. The main analytical challenge to establishing liquid biopsy in clinical practice is the development of biosensors able to detect intact exosomes concentration and simultaneously analyze specific membrane biomarkers and those contained in their cargo. Before analysis, exosomes also need to be isolated from biological fluids. Microfluidic systems can address several issues present in conventional methods (i.e., ultracentrifugation, size-exclusion chromatography, ultrafiltration, and immunoaffinity capture), which are time-consuming and require a relatively high amount of sample; in addition, they can be easily integrated with biosensing systems. A critical review of emerging microfluidic-based devices for integrated biosensing approaches and following the major analytical need for accurate diagnostics is presented here. The design of a new miniaturized biosensing system is also reported. A device based on hollow-fiber flow field-flow fractionation followed by luminescence-based immunoassay is applied to isolate intact exosomes and characterize their cargo as a proof of concept for colon cancer diagnosis.

Microfluidic Blood Separation: Key Technologies and Critical Figures of Merit

Blood is a complex sample comprised mostly of plasma, red blood cells (RBCs), and other cells whose concentrations correlate to physiological or pathological health conditions. There are also many blood-circulating biomarkers, such as circulating tumor cells (CTCs) and various pathogens, that can be used as measurands to diagnose certain diseases. Microfluidic devices are attractive analytical tools for separating blood components in point-of-care (POC) applications. These platforms have the potential advantage of, among other features, being compact and portable. These features can eventually be exploited in clinics and rapid tests performed in households and low-income scenarios. Microfluidic systems have the added benefit of only needing small volumes of blood drawn from patients (from nanoliters to milliliters) while integrating (within the devices) the steps required before detecting analytes. Hence, these systems will reduce the associated costs of purifying blood components of interest (e.g., specific groups of cells or blood biomarkers) for studying and quantifying collected blood fractions. The microfluidic blood separation field has grown since the 2000s, and important advances have been reported in the last few years. Nonetheless, real POC microfluidic blood separation platforms are still elusive. A widespread consensus on what key figures of merit should be reported to assess the quality and yield of these platforms has not been achieved. Knowing what parameters should be reported for microfluidic blood separations will help achieve that consensus and establish a clear road map to promote further commercialization of these devices and attain real POC applications. This review provides an overview of the separation techniques currently used to separate blood components for higher throughput separations (number of cells or particles per minute). We present a summary of the critical parameters that should be considered when designing such devices and the figures of merit that should be explicitly reported when presenting a device's separation capabilities. Ultimately, reporting the relevant figures of merit will benefit this growing community and help pave the road toward commercialization of these microfluidic systems.

Direct isolation of small extracellular vesicles from human blood using viscoelastic microfluidics

Small extracellular vesicles (sEVs; <200 nm) that contain lipids, nucleic acids, and proteins are considered promising biomarkers for a wide variety of diseases. Conventional methods for sEV isolation from blood are incompatible with routine clinical workflows, significantly hampering the utilization of blood-derived sEVs in clinical settings. Here, we present a simple, viscoelastic-based microfluidic platform for label-free isolation of sEVs from human blood. The separation performance of the device is assessed by isolating fluorescent sEVs from whole blood, demonstrating purities and recovery rates of over 97 and 87%, respectively. Significantly, our viscoelastic-based microfluidic method also provides for a remarkable increase in sEV yield compared to gold-standard ultracentrifugation, with proteomic profiles of blood-derived sEVs purified by both methods showing similar protein compositions. To demonstrate the clinical utility of the approach, we isolate sEVs from blood samples of 20 patients with cancer and 20 healthy donors, demonstrating that elevated sEV concentrations can be observed in blood derived from patients with cancer.

Recent progress in the effect of magnetic iron oxide nanoparticles on cells and extracellular vesicles

At present, iron oxide nanoparticles (IONPs) are widely used in the biomedical field. They have unique advantages in targeted drug delivery, imaging and disease treatment. However, there are many things to pay attention to. In this paper, we reviewed the fate of IONPs in different cells and the influence on the production, separation, delivery and treatment of extracellular vesicles. It aims to provide cutting-edge knowledge related to iron oxide nanoparticles. Only by ensuring the safety and effectiveness of IONPs can their application in biomedical research and clinic be further improved.

Emerging integrated SERS-microfluidic devices for analysis of cancer-derived small extracellular vesicles

Cancer-derived small extracellular vesicles (sEVs) are specific subgroups of lipid bilayer vesicles secreted from cancer cells to the extracellular environment. They carry distinct biomolecules (e.g., proteins, lipids and nucleic acids) from their parent cancer cells. Therefore, the analysis of cancer-derived sEVs can provide valuable information for cancer diagnosis. However, the use of cancer-derived sEVs in clinics is still limited due to their small size, low amounts in circulating fluids, and heterogeneous molecular features, making their isolation and analysis challenging. Recently, microfluidic technology has gained great attention for its ability to isolate sEVs in minimal volume. In addition, microfluidics allows the isolation and detection of sEVs to be integrated into a single device, offering new opportunities for clinical application. Among various detection techniques, surface-enhanced Raman scattering (SERS) has emerged as a promising candidate for integrating with microfluidic devices due to its ultra-sensitivity, stability, rapid readout, and multiplexing capability. In this tutorial review, we start with the design of microfluidics devices for isolation of sEVs and introduce the key factors to be considered for the design, and then discuss the integration of SERS and microfluidic devices by providing descriptive examples of the currently developed platforms. Lastly, we discuss the current limitations and provide our insights for utilising integrated SERS-microfluidics to isolate and analyse cancer-derived sEVs in clinical settings.

Can the molecules carried by extracellular vesicles help to diagnose pancreatic cancer early?

BACKGROUND

Pancreatic cancer is a deadly malignancy mainly because of its asymptomatic onset which prevents the implementation of the primary tumour's resection surgery, leading to metastatic spread resistant to chemotherapy. Early-detection of this cancer in its initial stage would represent a game changer in the fight against this disease. The few currently available biomarkers detectable in patients' body fluids lack sensitivity and specificity.

SCOPE OF REVIEW

The recent discovery of extracellular vesicles and their role in promoting cancer's advancement, has boosted interest in researching their cargo, to find reliable early detection biological markers. This review examines the most recent discoveries in the analysis of potential extra vesicle-carried biological markers for the early detection of pancreatic cancer.

MAJOR CONCLUSIONS

Despite the advantages of using extracellular vesicles for early diagnosis, and the promising findings of extracellular vesicle-carried molecules possibly functional as biomarkers, until now there are no validated markers derived from extracellular vesicles available to be used in the clinic.

GENERAL SIGNIFICANCE

Further studies in this direction are urgently required to provide what would be a major asset for defeating pancreatic cancer.

A novel combination for the treatment of small cell lung cancer: Active targeted irinotecan and stattic co-loaded PLGA nanoparticles

Polymeric nanoparticles are widely used drug delivery systems for cancer treatment due to their properties such as ease of passing through biological membranes, opportunity to modify drug release, specifically targeting drugs to diseased areas, and potential of reducing side effects. Here, we formulated irinotecan and Stattic co-loaded PLGA nanoparticles targeted to small cell lung cancer. Nanoparticles were successfully conjugated with CD56 antibody with a conjugation efficiency of 84.39 ± 1.01%, and characterization of formulated nanoparticles was conducted with in-vitro and in-vivo studies. Formulated particles had sizes in the range of 130-180 nm with PDI values smaller than 0.3. Encapsulation and active targeting of irinotecan and Stattic resulted in increased cytotoxicity and anti-cancer efficiency in-vitro. Furthermore, it was shown with ex-vivo biodistribution studies that conjugated nanoparticles were successfully targeted to CD56-expressing SCLC cells and distributed mainly to tumor tissue and lungs. Compliant with our hypothesis and literature, the STAT3 pathway was successfully inhibited with Stattic solution and Stattic loaded nanoparticles. Additionally, intravenous injection of conjugated co-loaded nanoparticles resulted in decreased side effects and better anti-tumor activity than individual solutions of drugs in SCLC tumor-bearing mice. These results may indicate a new treatment option for clinically aggressive small cell lung cancer.

Microfluidics facilitating the use of small extracellular vesicles in innovative approaches to male infertility

Sperm are transcriptionally and translationally quiescent and, therefore, rely on the seminal plasma microenvironment for function, survival and fertilization of the oocyte in the oviduct. The male reproductive system influences sperm function via the binding and fusion of secreted epididymal (epididymosomes) and prostatic (prostasomes) small extracellular vesicles (S-EVs) that facilitate the transfer of proteins, lipids and nucleic acids to sperm. Seminal plasma S-EVs have important roles in sperm maturation, immune and oxidative stress protection, capacitation, fertilization and endometrial implantation and receptivity. Supplementing asthenozoospermic samples with normospermic-derived S-EVs can improve sperm motility and S-EV microRNAs can be used to predict non-obstructive azoospermia. Thus, S-EV influence on sperm physiology might have both therapeutic and diagnostic potential; however, the isolation of pure populations of S-EVs from bodily fluids with current conventional methods presents a substantial hurdle. Many conventional techniques lack accuracy, effectiveness, and practicality; yet microfluidic technology has the potential to simplify and improve S-EV isolation and detection.

The emerging role of exosomes in innate immunity, diagnosis and therapy

Exosomes, which are nano-sized transport bio-vehicles, play a pivotal role in maintaining homeostasis by exchanging genetic or metabolic information between different cells. Exosomes can also play a vital role in transferring virulent factors between the host and parasite, thereby regulating host gene expression and the immune interphase. The association of inflammation with disease development and the potential of exosomes to enhance or mitigate inflammatory pathways support the notion that exosomes have the potential to alter the course of a disease. Clinical trials exploring the role of exosomes in cancer, osteoporosis, and renal, neurological, and pulmonary disorders are currently underway. Notably, the information available on the signatory efficacy of exosomes in immune-related disorders remains elusive and sporadic. In this review, we discuss immune cell-derived exosomes and their application in immunotherapy, including those against autoimmune connective tissue diseases. Further, we have elucidated our views on the major issues in immune-related pathophysiological processes. Therefore, the information presented in this review highlights the role of exosomes as promising strategies and clinical tools for immune regulation.

Isolation of Extracellular Vesicles by a Microfluidic Platform to Diagnose and Monitor Pancreatic Cancer

Exosomes are extracellular vesicles that are involved in cell-cell communication. Considering their bioavailability and accessibility in all the body fluids (including the blood, semen, breast milk, saliva, and urine), their use has been proposed as an alternative noninvasive tool for the diagnosis, monitoring, and prognosis of several diseases, including cancer. The isolation of exosomes and their subsequent analysis are emerging as a promising technique in diagnostics and personalized medicine. The most widely employed isolation procedure is differential ultracentrifugation, but this approach is laborious, time-consuming, and expensive and with limited isolation yield. Microfluidic devices are now emerging as novel platforms for exosome isolation, which is a low cost technology and enables high purity and fast treatment of exosome isolation. Our approach describes a microfluidic device that enables inflow capture and separation from whole blood using antibody-functionalized magnetic nanoparticles. This device allows isolation of pancreatic cancer-derived exosomes from whole blood without the need of any pretreatment, resulting in a high sensitivity.

Advancement and obstacles in microfluidics-based isolation of extracellular vesicles

There is a great need for techniques which enable reproducible separation of extracellular vesicles (EVs) from biofluids with high recovery, purity and throughput. The development of new techniques for isolation of EVs from minute sample volumes is instrumental in enabling EV-based biomarker profiling in large biobank cohorts and paves the way to improved diagnostic profiles in precision medicine. Recent advances in microfluidics-based devices offer a toolbox for separating EVs from small sample volumes. Microfluidic devices that have been used in EV isolation utilise different fundamental principles and rely largely on benefits of scaling laws as the biofluid processing is miniaturised to chip level. Here, we review the progress in the practicality and performance of both passive devices (such as mechanical filtering and hydrodynamic focusing) and active devices (using magnetic, electric or acoustic fields). As it stands, many microfluidic devices isolate intact EV populations at higher purities than centrifugation, precipitation or size-exclusion chromatography. However, this comes at a cost. We address challenges (in particular low throughput, clogging risks and ability to process biofluids) and highlight the need for more improvements in microfluidic devices. Finally, we conclude that there is a need to refine and standardise these lab-on-a-chip techniques to meet the growing interest in the diagnostic and therapeutic value of purified EVs.

Microfluidic Strategies for Extracellular Vesicle Isolation: Towards Clinical Applications

Extracellular vesicles (EVs) are double-layered lipid membrane vesicles released by cells. Currently, EVs are attracting a lot of attention in the biological and medical fields due to their role as natural carriers of proteins, lipids, and nucleic acids. Thus, they can transport useful genomic information from their parental cell through body fluids, promoting cell-to-cell communication even between different organs. Due to their functionality as cargo carriers and their protein expression, they can play an important role as possible diagnostic and prognostic biomarkers in various types of diseases, e.g., cancers, neurodegenerative, and autoimmune diseases. Today, given the invaluable importance of EVs, there are some pivotal challenges to overcome in terms of their isolation. Conventional methods have some limitations: they are influenced by the starting sample, might present low throughput and low purity, and sometimes a lack of reproducibility, being operator dependent. During the past few years, several microfluidic approaches have been proposed to address these issues. In this review, we summarize the most important microfluidic-based devices for EV isolation, highlighting their advantages and disadvantages compared to existing technology, as well as the current state of the art from the perspective of the use of these devices in clinical applications.

Extracellular vesicles as source for the identification of minimally invasive molecular signatures in glioblastoma

The analysis of extracellular vesicles (EVs) as a source of cancer biomarkers is an emerging field since low-invasive biomarkers are highly demanded. EVs constitute a heterogeneous population of small membrane-contained vesicles that are present in most of body fluids. They are released by all cell types, including cancer cells and their cargo consists of nucleic acids, proteins and metabolites and varies depending on the biological-pathological state of the secretory cell. Therefore, EVs are considered as a potential source of reliable biomarkers for cancer. EV biomarkers in liquid biopsy can be a valuable tool to complement current medical technologies for cancer diagnosis, as their sampling is minimally invasive and can be repeated over time to monitor disease progression. In this review, we highlight the advances in EV biomarker research for cancer diagnosis, prognosis, and therapy monitoring. We especially focus on EV derived biomarkers for glioblastoma. The diagnosis and monitoring of glioblastoma still relies on imaging techniques, which are not sufficient to reflect the highly heterogenous and invasive nature of glioblastoma. Therefore, we discuss how the use of EV biomarkers could overcome the challenges faced in diagnosis and monitoring of glioblastoma.

Lectin-Based Study Reveals the Presence of Disease-Relevant Glycoepitopes in Bladder Cancer Cells and Ectosomes

Bladder cancer is a malignancy that remains a therapeutic challenge and requires the identification of new biomarkers and mechanisms of progression. Several studies showed that extracellular vesicles promote angiogenesis, migration and metastasis, and inhibit apoptosis in bladder cancer. This effect may depend on their glycosylation status. Thus, the aim of this study was to compare glycosylation profiles of T-24 urothelial bladder cancer cells, HCV-29 normal ureter epithelial cells, and ectosomes released by both cell lines using lectin blotting and flow cytometry. Ectosomes displayed distinct total and surface glycosylation profiles with abundance of β-1,6-branched glycans and sialilated structures. Then, it was investigated whether the glycosylation status of the T-24 and HCV-29 cells is responsible for the effect exerted by ectosomes on the proliferation and migration of recipient cells. Stronger proproliferative and promigratory activity of T-24-derived ectosomes was observed in comparison to ectosomes from HCV-29 cells. When ectosomes were isolated from DMJ-treated cells, the aforementioned effects were diminished, suggesting that glycans carried by ectosomes were involved in modulation of recipient cell function. HCV-29- and T-24-derived ectosomes also increased the viability and motility of endothelial HUVEC cells and Hs27 fibroblasts. This supports the hypothesis that ectosomes can modulate the function of various cells present in the tumor microenvironment.

Application of extracellular vesicles proteins in cancer diagnosis

Early tumor diagnosis is crucial for its treatment and reduction of death, with effective tumor biomarkers being important tools. Extracellular vesicles (EVs) are small vesicles secreted by cells with various biomolecules, including proteins, nucleic acids, and lipids. They harbor a double membrane structure. Previous studies on EVs in cancer diagnosis and therapy focused on miRNAs. Nonetheless, EVs contain proteins that represent physiological and pathological state of their parental cells. EVs proteins can reflect the pathological state of some diseases, which provides a basis for diagnosis and treatment. This study describes the role of EVs in cancer and summarizes the use of EVs proteins as diagnostic markers in different cancer types. Specifically, we discuss the potential and shortcomings of EVs as tumor biomarkers.

Molecular Docking and Intracellular Translocation of Extracellular Vesicles for Efficient Drug Delivery

Extracellular vesicles (EVs), including exosomes, mediate intercellular communication by delivering their contents, such as nucleic acids, proteins, and lipids, to distant target cells. EVs play a role in the progression of several diseases. In particular, programmed death-ligand 1 (PD-L1) levels in exosomes are associated with cancer progression. Furthermore, exosomes are being used for new drug-delivery systems by modifying their membrane peptides to promote their intracellular transduction via micropinocytosis. In this review, we aim to show that an efficient drug-delivery system and a useful therapeutic strategy can be established by controlling the molecular docking and intracellular translocation of exosomes. We summarise the mechanisms of molecular docking of exosomes, the biological effects of exosomes transmitted into target cells, and the current state of exosomes as drug delivery systems.

Strategies to overcome the main challenges of the use of exosomes as drug carrier for cancer therapy

Exosomes are naturally occurring nanosized particles that aid intercellular communication by transmitting biological information between cells. Exosomes have therapeutic efficacy that can transfer their contents between cells as natural carriers. In addition, the exosomal contents delivered to the recipient pathological cells significantly inhibit cancer progression. However, exosome-based tumor treatments are inadequately precise or successful, and various challenges should be adequately overcome. Here, we discuss the significant challenges that exosomes face as drug carriers used for therapeutic targets and strategies for overcoming these challenges in order to promote this new incoming drug carrier further and improve future clinical outcomes. We also present techniques for overcoming these challenges.

Microfluidic Technology for the Isolation and Analysis of Exosomes

Exosomes are lipid-bilayer enclosed vesicles with diameters of 30-150 nm, which play a pivotal role in cell communication by transporting their cargoes such as proteins, lipids, and genetic materials. In recent years, exosomes have been under intense investigation, as they show great promise in numerous areas, especially as bio-markers in liquid biopsies. However, due to the high heterogeneity and the nano size of exosomes, the separation of exosomes is not easy. This review will deliver an outline of the conventional methods and the microfluidic-based technologies for exosome separation. Particular attention is devoted to microfluidic devices, highlighting the efficiency of exosome isolation by these methods. Additionally, this review will introduce advances made in the integrated microfluidics technologies that enable the separation and analysis of exosomes.

Multiplexed strategies toward clinical translation of extracellular vesicles

Extracellular vesicles (EVs), of which exosomes are a representative subgroup, are naturally secreted nanoparticles with a variety of payloads. With the intrinsic merits of stability, biocompatibility, low immunogenicity, and large capacity, EVs are widely regarded as effective carriers of drug delivery. However, disadvantages, such as low yield, complicated isolation procedures, and low loading efficiency, hinder its clinical translation. In this review, we systematically summarize the advances in EV (especially exosomes) engineering for clinical application, focusing on strategies toward high yield, facile isolation, efficient cargo loading, improved delivery, and optimized manufacturing, which might unleash the infinite power of EVs in clinical translation.

Recent progresses in exosome-based systems for targeted drug delivery to the brain

Despite the multiple ongoing and novel initiatives for developing brain-targeted drug delivery systems, insurmountable obstacles remain. A perfect drug delivery device that can bypass the brain-blood barrier and boost therapeutic efficacy is urgently needed for clinical applications. Exosomes hold unrivaled benefits as a drug delivery vehicle for treating brain diseases due to their endogenous and innate attributes. Unique properties, such as the ability to penetrate physical barriers, biocompatibility, innate targeting features, ability to leverage natural intracellular trafficking pathways, favored tumor homing, and stability, make exosomes suitable for brain-targeted drug delivery. Herein, we provide an overview of recent exosome-based drug delivery nanoplatforms and discuss how these inherent vesicles can be used to deliver therapeutic agents to the brain to cure neurodegenerative diseases, brain tumors, and other brain disorders. Moreover, we review the current roadblocks associated with exosomes and other brain-targeted drug delivery systems and discuss future directions for achieving successful therapy outcomes.

Microfluidics for detection of exosomes and microRNAs in cancer: State of the art

Exosomes are small extracellular vesicles with sizes ranging from 30-150 nanometers that contain proteins, lipids, mRNAs, microRNAs, and double-stranded DNA derived from the cells of origin. Exosomes can be taken up by target cells, acting as a means of cell-to-cell communication. The discovery of these vesicles in body fluids and their participation in cell communication has led to major breakthroughs in diagnosis, prognosis, and treatment of several conditions (e.g., cancer). However, conventional isolation and evaluation of exosomes and their microRNA content suffers from high cost, lengthy processes, difficult standardization, low purity, and poor yield. The emergence of microfluidics devices with increased efficiency in sieving, trapping, and immunological separation of small volumes could provide improved detection and monitoring of exosomes involved in cancer. Microfluidics techniques hold promise for advances in development of diagnostic and prognostic devices. This review covers ongoing research on microfluidics devices for detection of microRNAs and exosomes as biomarkers and their translation to point-of-care and clinical applications.

Small extracellular vesicles (exosomes) and their cargo in pancreatic cancer: Key roles in the hallmarks of cancer

Pancreatic cancer (PC) is a devastating disease, offering poor mortality rates for patients. The current challenge being faced is the inability to diagnose patients in a timely manner, where potentially curative resection provides the best chance of survival. Recently, small/nanosized extracellular vesicles (sEVs), including exosomes, have gained significant preclinical and clinical attention due to their emerging roles in cancer progression and diagnosis. Extracellular vesicles (EVs) possess endogenous properties that offer stability and facilitate crossing of biological barriers for delivery of molecular cargo to cells, acting as a form of intercellular communication to regulate function and phenotype of recipient cells. This review provides an overview of the role of EVs, their subtypes and their oncogenic cargo (as characterised by targeted studies as well as agnostic '-omics' analyses) in the pathobiology of pancreatic cancer. The discussion covers the progress of 'omics technology' that has enabled elucidation of the molecular mechanisms that mediate the role of EVs and their cargo in pancreatic cancer progression.

Challenges in the Development of Drug Delivery Systems Based on Small Extracellular Vesicles for Therapy of Brain Diseases

Small extracellular vesicles (sEVs) have ∼30–200 nm diameter size and may act as carriers of different cargoes, depending on the cell of origin or on the physiological/pathological condition. As endogenous nanovesicles, sEVs are important in intercellular communication and have many of the desirable features of an ideal drug delivery system. sEVs are naturally biocompatible, with superior targeting capability, safety profile, nanometric size, and can be loaded with both lipophilic and hydrophilic agents. Because of their biochemical and physical properties, sEVs are considered a promising strategy over other delivery vehicles in the central nervous system (CNS) since they freely cross the blood-brain barrier and they can be directed to specific nerve cells, potentiating a more precise targeting of their cargo. In addition, sEVs remain stable in the peripheral circulation, making them attractive nanocarrier systems to promote neuroregeneration. This review focuses on the recent progress in methods for manufacturing, isolating, and engineering sEVs that can be used as a therapeutic strategy to overcome neurodegeneration associated with pathologies of the CNS, with particular emphasis on Alzheimer’s, Parkinson’s, and amyotrophic lateral sclerosis diseases, as well as on brain tumors.

Harnessing the Therapeutic Potential of Extracellular Vesicles for Biomedical Applications Using Multifunctional Magnetic Nanomaterials

Extracellular vesicles (e.g., exosomes) carrying various biomolecules (e.g., proteins, lipids, and nucleic acids) have rapidly emerged as promising platforms for many biomedical applications. Despite their enormous potential, their heterogeneity in surfaces and sizes, the high complexity of cargo biomolecules, and the inefficient uptake by recipient cells remain critical barriers for their theranostic applications. To address these critical issues, multifunctional nanomaterials, such as magnetic nanomaterials, with their tunable physical, chemical, and biological properties, may play crucial roles in next-generation extracellular vesicles (EV)-based disease diagnosis, drug delivery, tissue engineering, and regenerative medicine. As such, one aims to provide cutting-edge knowledge pertaining to magnetic nanomaterials-facilitated isolation, detection, and delivery of extracellular vesicles and their associated biomolecules. By engaging the fields of extracellular vesicles and magnetic nanomaterials, it is envisioned that their properties can be effectively combined for optimal outcomes in biomedical applications.

Review on Strategies and Technologies for Exosome Isolation and Purification

Exosomes, a nano-sized subtype of extracellular vesicles secreted from almost all living cells, are capable of transferring cell-specific constituents of the source cell to the recipient cell. Cumulative evidence has revealed exosomes play an irreplaceable role in prognostic, diagnostic, and even therapeutic aspects. A method that can efficiently provide intact and pure exosomes samples is the first step to both exosome-based liquid biopsies and therapeutics. Unfortunately, common exosomal separation techniques suffer from operation complexity, time consumption, large sample volumes and low purity, posing significant challenges for exosomal downstream analysis. Efficient, simple, and affordable methods to isolate exosomes are crucial to carrying out relevant researches. In the last decade, emerging technologies, especially microfluidic chips, have proposed superior strategies for exosome isolation and exhibited fascinating performances. While many excellent reviews have overviewed various methods, a compressive review including updated/improved methods for exosomal isolation is indispensable. Herein, we first overview exosomal properties, biogenesis, contents, and functions. Then, we briefly outline the conventional technologies and discuss the challenges of clinical applications of these technologies. Finally, we review emerging exosomal isolation strategies and large-scale GMP production of engineered exosomes to open up future perspectives of next-generation Exo-devices for cancer diagnosis and treatment.

Exploration of Exosomal miRNAs from Serum and Synovial Fluid in Arthritis Patients

Arthritis is caused by inflammation, infection, degeneration, trauma, or other factors that affect approximately 250 million people all over the world. Early diagnosis and prediction are essential for treatment. Exosomes are nanoscale vesicles that participate in the process of joint disease. Serum is the mainly used sources in the study of arthritis-related exosomes, while whether serum exosomes can reflect the contents of synovial fluid exosomes is still unknown. In this work, we separated exosomes from serum and the synovial fluid of osteoarthritis patients and compared their miRNA expression utilizing miRNA sequencing. The results revealed that 31 upregulated and 33 downregulated miRNAs were found in synovial fluid compared to serum. Transcriptome analysis showed that these differentially expressed miRNAs were mainly associated with intercellular processes and metabolic pathways. Our results show that serum-derived exosomes cannot fully represent the exosomes of synovial fluid, which may be helpful for the study of joint diseases and the discovery of early diagnostic biomarkers of arthritis.

Methodologies to Isolate and Purify Clinical Grade Extracellular Vesicles for Medical Applications

The use of extracellular vesicles (EV) in nano drug delivery has been demonstrated in many previous studies. In this study, we discuss the sources of extracellular vesicles, including plant, salivary and urinary sources which are easily available but less sought after compared with blood and tissue. Extensive research in the past decade has established that the breadth of EV applications is wide. However, the efforts on standardizing the isolation and purification methods have not brought us to a point that can match the potential of extracellular vesicles for clinical use. The standardization can open doors for many researchers and clinicians alike to experiment with the proposed clinical uses with lesser concerns regarding untraceable side effects. It can make it easier to identify the mechanism of therapeutic benefits and to track the mechanism of any unforeseen effects observed.

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.

Diverse Effects of Exosomes on COVID-19: A Perspective of Progress From Transmission to Therapeutic Developments

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new strain of coronavirus and the causative agent of the current global pandemic of coronavirus disease 2019 (COVID-19). There are currently no FDA-approved antiviral drugs for COVID-19 and there is an urgent need to develop treatment strategies that can effectively suppress SARS-CoV-2 infection. Numerous approaches have been researched so far, with one of them being the emerging exosome-based therapies. Exosomes are nano-sized, lipid bilayer-enclosed structures, share structural similarities with viruses secreted from all types of cells, including those lining the respiratory tract. Importantly, the interplay between exosomes and viruses could be potentially exploited for antiviral drug and vaccine development. Exosomes are produced by virus-infected cells and play crucial roles in mediating communication between infected and uninfected cells. SARS-CoV-2 modulates the production and composition of exosomes, and can exploit exosome formation, secretion, and release pathways to promote infection, transmission, and intercellular spread. Exosomes have been exploited for therapeutic benefits in patients afflicted with various diseases including COVID-19. Furthermore, the administration of exosomes loaded with immunomodulatory cargo in combination with antiviral drugs represents a novel intervention for the treatment of diseases such as COVID-19. In particular, exosomes derived from mesenchymal stem cells (MSCs) are used as cell-free therapeutic agents. Mesenchymal stem cell derived exosomes reduces the cytokine storm and reverse the inhibition of host anti-viral defenses associated with COVID-19 and also enhances mitochondrial function repair lung injuries. We discuss the role of exosomes in relation to transmission, infection, diagnosis, treatment, therapeutics, drug delivery, and vaccines, and present some future perspectives regarding their use for combating COVID-19.

Exosomes for mRNA delivery: a novel biotherapeutic strategy with hurdles and hope

Over the past decade, therapeutic messenger RNAs (mRNAs) have emerged as a highly promising new class of drugs for protein replacement therapies. Due to the recent developments, the incorporation of modified nucleotides in synthetic mRNAs can lead to maximizing protein expression and reducing adverse immunogenicity. Despite these stunning improvements, mRNA therapy is limited by the need for the development of safe and efficient carriers to protect the mRNA integrity for in vivo applications. Recently, leading candidates for in vivo drug delivery vehicles are cell-derived exosomes, which have fewer immunogenic responses. In the current study, the key hurdles facing mRNA-based therapeutics, with an emphasis on recent strategies to overcoming its immunogenicity and instability, were highlighted. Then the immunogenicity and toxicity of exosomes derived from various cell sources were mentioned in detail. Finally, an overview of the recent strategies in using exosomes for mRNA delivery in the treatment of multiple diseases was stated.

Therapeutic Application of Exosomes in Inflammatory Diseases

Immunomodulation is on the cusp of being an important therapy for treating many diseases, due to the significant role of the immune system in defending the human body. Although the immune system is an essential defense system, overactivity can result in diverse sicknesses such as inflammation and autoimmune disease. Exosomes are emerging as a state-of-the-art therapeutic strategy for treating an overactive immune system. Thus, in this review, we will thoroughly review therapeutic applications of exosomes in various inflammatory and autoimmune diseases. Finally, issues for an outlook to the future of exosomal therapy will be introduced.

Glycosylation of Cancer Extracellular Vesicles: Capture Strategies, Functional Roles and Potential Clinical Applications

Glycans are major constituents of extracellular vesicles (EVs). Alterations in the glycosylation pathway are a common feature of cancer cells, which gives rise to de novo or increased synthesis of particular glycans. Therefore, glycans and glycoproteins have been widely used in the clinic as both stratification and prognosis cancer biomarkers. Interestingly, several of the known tumor-associated glycans have already been identified in cancer EVs, highlighting EV glycosylation as a potential source of circulating cancer biomarkers. These particles are crucial vehicles of cell–cell communication, being able to transfer molecular information and to modulate the recipient cell behavior. The presence of particular glycoconjugates has been described to be important for EV protein sorting, uptake and organ-tropism. Furthermore, specific EV glycans or glycoproteins have been described to be able to distinguish tumor EVs from benign EVs. In this review, the application of EV glycosylation in the development of novel EV detection and capture methodologies is discussed. In addition, we highlight the potential of EV glycosylation in the clinical setting for both cancer biomarker discovery and EV therapeutic delivery strategies.