Reversible zwitterionic coordination enables rapid, high-yield, and high-purity isolation of extracellular vesicles from biofluids

TiO2-coated honeycomb-like super-macroporous silica for high-purity extraction of exosomes from human plasma

Screening biomarkers from exosomes has emerged as a new strategy for non-invasive early diagnosis of diseases. Nevertheless, the present screening efficiency and accuracy of biomarkers are limited by the low extraction efficiency and purity of exosomes. To address this issue, a highly selective adsorbent, which integrates size-exclusion and chemisorption, was created by coating TiO2 on honeycomb-like super-macroporous silica. Cell culture medium and human plasma were employed to investigate the enrichment performance, and the results indicate that the super-macropores ranging from 63.5 to 147.5 nm together with thin pore walls allow exosomes to enter and be adsorbed by TiO2 in the pores, enhancing the available surface area for exosomes meanwhile physically excluding the large-sized cell debris and vesicles. Taking advantages of these properties, the prepared adsorbent achieves a higher extraction efficiency, recovery and purity of exosomes compared with the normal adsorbents and ultracentrifugation (UC) method. Combining this method with proteomic analysis, a total of 392 proteins were identified in exosomes from healthy human plasma, which is significantly higher than the number obtained by UC (200 proteins). For clinical samples, 59 upregulated and 124 downregulated proteins were identified in the plasma from colorectal cancer (CRC) patients, of which 44 upregulated proteins and 69 downregulated proteins are strongly associated with the progression of CRC. These findings suggest that this adsorbent possesses considerable potential in the extraction of exosomes for screening biomarkers and diagnosing tumor progress.

Wash-Free Isolation and Quantification of Tumor-Derived Exosomes via In Situ-Formed Hydrogel

The isolation and detection of exosomes as tumor markers are of vital importance for the early diagnosis, therapeutic monitoring, and mechanistic studies of tumors. Here, exosomes derived from breast cancer cells were chosen as model targets, and a wash-free, enzyme-free, handheld mini centrifugation method based on hydrogels was developed to effectively isolate and detect breast cancer exosomes. Dual aptamers (CD63-T1 and EpCAM-T2) were employed to specifically recognize and capture breast cancer exosomes. This specific recognition triggered the formation of hybridization chain reaction (HCR) nanostructures on the captured exosomes through the interaction of hairpin 1 and the alginate complex (H1-Alg) and hairpin 2 (H2-Cy3). The interaction of Ca2+ and alginate enabled the in situ formation of a hydrogel on the exosome surface. Subsequent low-speed centrifugation using a handheld mini centrifuge facilitated the efficient isolation of the exosomes, thereby eliminating the need for tedious washing steps. Utilizing the classical chelation reaction of ethylene diamine tetraacetic acid (EDTA) with Ca2+, the hydrogel can be rapidly cleaved for enzyme-free release of exosomes. The method demonstrated excellent capture and release efficiencies of approximately 85% and 98%, respectively, for specific cancerous exosomes. Notably, the exosomes isolated by the hydrogel system retained excellent biological activity, making them suitable for further analysis and potential applications. Meanwhile, the highly sensitive detection of breast cancer exosomes based on this strategy could also be achieved with a lower limit of detection as low as 3.2 × 103 particles/mL. This work provides a novel and cost-effective strategy for the effective isolation and detection of tumor-derived exosomes, which can help to promote the subsequent application of exosomes in research.

Self-Adaptive Release of Stem Cell-Derived Exosomes from a Multifunctional Hydrogel for Accelerating MRSA-Infected Diabetic Wound Repair

Chronic diabetic wounds are prone to severe skin necrosis and bacterial infections, with elevated reactive oxygen species (ROS) and persistent inflammation further hindering the healing process. Developing smart dressings with multifunctional therapeutic capabilities to simultaneously combat infections, reduce oxidative stress, alleviate inflammation, and promote tissue regeneration remains a significant challenge. Here, we introduce a self-adaptive yet multifunctional hydrogel (Exo-Gel) designed to accelerate methicillin-resistant Staphylococcus aureus (MRSA)-infected diabetic wound repair. Exo-Gel utilizes choline phosphate (CP) groups to both anchor stem cell-derived exosomes (Exo) via electrostatic interactions and disrupt bacterial membranes, providing inherent bacteriostatic effects. Additionally, ROS-responsive thioketal (TK) linkers enable the self-adaptive release of exosomes based on local ROS levels while also scavenging excess ROS. This synergistic system facilitates wound healing by modulating oxidative stress, reducing inflammation, promoting M2 macrophage polarization, and enhancing cell proliferation, myofibroblast migration, angiogenesis, and collagen deposition to accelerate tissue regeneration. In diabetic Sprague-Dawley rats with MRSA-infected full-thickness wounds, Exo-Gel achieved remarkable bacteriostatic activity and accelerated wound healing. Exo-Gel offers a cost-effective, multifunctional, and self-adaptive therapeutic strategy for managing chronic diabetic wounds, requiring no external components or operations, making it highly practical and translatable for clinical applications.

Ultrasensitive Profiling of Plasma Extracellular Vesicles for Breast Cancer Subtyping with a High-Curvature Antifouling Nanoarray

Profiling of plasma extracellular vesicles (EVs) has long been hampered by their insufficient capture and assay sensitivity due to the high background of complex matrices. To address this challenge, we develop a high-curvature antifouling nanoarray electrochemical assay (eCAN) to enable ultrasensitive and specific profiling of plasma EVs for the accurate subtyping of breast cancer. This assay leverages a three-in-one multifunctional hierarchical antifouling nanofilm to improve EV capture, minimize nonspecific adsorption, and facilitate three-dimensional deposition of tyramine for signal amplification. These advantages allow the eCAN to achieve a sensitivity of up to 56 particles/mL (near a single-EV level), showing high specificity and anti-interference. The eCAN can differentiate EV subpopulations across different breast cancer cells and monitor their phenotypic changes. This assay allows accurate diagnosis and subtyping of breast cancer (AUC = 1.000) through direct profiling of EVs in undiluted plasma from a pilot cohort and provides a promising tool for precise diagnosis of cancers in clinical settings.

[Exosome separation and enrichment technologies and their applications in disease diagnosis and treatment]

Exosomes are nanoscale vesicles wrapped in lipid bilayers that are secreted by cells and carry a variety of proteins, lipids, nucleic acids, and metabolites. Exosomes are widely present in various bodily fluids and mediate intercellular communication. They participate in a variety of physiological and pathological processes, including immune regulation, angiogenesis, tumorigenesis, and metastasis, and have significant clinical diagnosis and treatment potential. Exosomes are source-rich, structurally stable, and reflect the states of their parental cells. Therefore, they are expected to serve as novel diagnostic markers for various diseases. In addition, stem-cell-derived exosomes show therapeutic potential and have the advantages of low immunogenicity, high safety and easy storage, and exhibit therapeutic potential for neurodegenerative disorder, cardiovascular disease, and cancer. Furthermore, exosomes are highly biocompatible, have natural homing properties, and are capable of easily penetrating biological barriers, making them excellent drug-delivery carriers. Isolation and enrichment of exosomes is a prerequisite for downstream analysis and application. High-purity, high-yield, and high-throughput exosome-isolation methods are expected to be used in clinical diagnosis and treatment applications. Based on the physicochemical properties of exosomes, including density, size, charge, and surface composition, exosome-isolation methods are mainly divided into density-based (e.g., differential ultracentrifugation, density-gradient ultracentrifugation), size-based (e.g., ultrafiltration, size-exclusion chromatography, field-flow fractionation), polymer-precipitation (e.g., polyethylene-glycol-based precipitation), and chemical affinity (e.g., antibody-based, aptamer-based, and surface-lipid-based lipid probes) methods. Currently, basic research into exosomes and their clinical applications face a number of challenges. Firstly, the complexity and heterogeneity of exosomes and the lack of standardized isolation methods has led to highly variable research results that hinder comparing and reproducing results between different laboratories and clinical settings. Current isolation methods are generally hindered by insufficient purity, low yield, low throughput, and difficulties separating specific subpopulations, which seriously restrict the development of the exosome field. Secondly, exosome-isolation methods that are easy to use in the clinic, have few technical requirements, and are highly efficient and inexpensive are lacking. Commonly used classical methods, such as ultracentrifugation, are time-consuming, labor-intensive, require large sample volumes, and are inappropriate for clinical settings. Methods such as immunoaffinity can be used to isolate exosomes from precious trace samples in clinical practice; however, high costs, low recoveries, and high operating requirements are shortcomings that restrict sample analysis in the clinic. In addition, robust large-scale methods for preparing exosomes are lacking. There is an urgent need to develop repeatable and scalable methods for preparing batches of high-quality exosomes owing to the rapid development of exosomes for the treatment of clinical diseases. Generally, exosome research progress is expected to greatly improve our understanding of the biological functions and components of exosomes, which will help transform the exosome research into effective diagnostic and therapeutic strategies and lead to new precision-medicine and personalized-treatment applications. This article summarizes the latest progress in exosome-isolation and -enrichment technologies and introduces the application of exosomes as disease diagnostic markers, therapeutic agents, and drug delivery carriers. Finally, the future developmental trends in exosome isolation and enrichment technologies for disease diagnosis and treatment are discussed.

[Research progress of peptide recognition-guided strategies for exosome isolation and enrichment]

Exosomes are bilayered vesicles derived from living cells and bacteria that are loaded with abundant biomolecules, such as proteins and nucleic acids. As an important medium of remote cell communication, exosomes are closely related to the occurrence and development of a number of diseases, including those involving tumors and inflammation. The isolation and enrichment of exosomes in complex biosystems is greatly significant for the diagnosis, prognosis, and detection of diseases, as well as in molecular-mechanism research. However, exosomes are usually nanoscale size distribution and widely existed in complex biological samples, including blood, tissue fluids, and urine, which bring difficulties and challenges to the isolation and enrichment of exosomes. To address this issue, several methods based on the physical properties of exosomes have been developed. For example, exosomes can be obtained by ultracentrifugation at high centrifugal force based on density differences; they can also be isolated and enriched by size-exclusion chromatography and ultrafiltration based on size heterogeneity. Exosomes can also be separated in high yields but with low purities using commercial polymer-coprecipitation-based isolation kits. While the abovementioned methods can be used to isolate and enrich exosomes in a highly efficient manner, accurately distinguishing interfering particles, including protein aggregates and microvesicles, in biosystems is still difficult, resulting in the poor purity of exosome isolation and enrichment. Affinity ligands are widely used during the affinity isolation and enrichment of exosomes. Antibodies exhibit high selectivity and affinity; consequently exosomes can be captured highly selectively by exploiting specific antigen/antibody interactions. However, antibodies also have some limitations, including complex preparation procedures, high costs, and poor stability. Chemical affinity ligands, such as aptamers, peptides, and small molecules, are also widely used to isolate and enrich exosomes. As a kind of molecular recognition tool, peptides contain a variety of amino acids and exhibit many advantages, including good biocompatibility, low immunogenicity, and design flexibility. Solid-phase synthesis strategies have rapidly developed, thereby providing a basis for automated and large-scale peptide synthesis. Affinity peptides have been widely used to recognize and analyze target biomolecules in complex physiological environments in a highly selective manner. A series of protein-targeting peptides has been reported based on the biomolecular characteristics of exosomes. These affinity peptides can be specifically anchored onto highly enriched transmembrane proteins on exosome surfaces, thereby enabling the efficient and highly selective isolation and enrichment of exosomes in complex systems. Additionally, exosomes contain stable bilayer membranes consisting of abundant and diverse phospholipid molecules. The development of phospholipid-molecule-targeting peptides is expected to effectively eliminate interference from protein aggregates and other particles. In addition to differences in the compositions of phospholipids in biofilms, exosomes are smaller and more curved than apoptotic bodies and microvesicles. A series of affinity peptides capable of inducing and sensing high membrane curvatures are widely used to isolate and enrich exosomes. The tumor microenvironment can produce and release tumor-derived exosomes that are buried in a large number of normal cell-derived exosomes. Accordingly, pH-responsive peptides have been designed and modified based on the acidic environments of tumor-derived exosomes, which were accurately and tightly anchored via peptide insertion and folding. Focusing on the current status of exosome research, this paper introduces and summarizes current and widely used methods for isolating and enriching exosomes. Various exosome-targeting peptide-design and screening principles are introduced based on the characteristics and advantages of peptides. The applications of these peptides to the isolation and enrichment of exosomes are also summarized, thereby providing strong guidance for the efficient and highly selective isolation and enrichment of exosomes in complex life-related systems.

[Typical strategy and research progress of efficient isolation methods of exosomes based on affinity interaction]

Exosomes form a subclass of extracellular vesicle that are secreted by most cells and found in nearly all body fluids, including blood, urine, saliva, amniotic fluid, and milk, as well as in various tissues and intercellular spaces. Exosomes have recently been recognized as crucial intercellular communication mediators, and an increasing number of studies have shown that exosomes are important liquid-biopsy tools that play irreplaceable roles in the diagnosis, prognosis, and treatment of diseases. The ability to isolate high-quality exosomes is a prerequisite for diagnosing and subsequently treating diseases in an accurate and repeatable manner. However, efficiently isolating exosomes from complex biological samples is challenging owing to their relatively low abundances and interference from non-vesicular macromolecules (such as cell debris and proteins). To date, various isolation techniques based on the physical, chemical, and biological characteristics of exosomes have been developed. Indeed, efficient affinity-interaction-based methods have recently overcome the limitations and drawbacks of traditional exosome isolation methods and are widely used in scientific research and clinical applications. This review focuses on exosome isolation and enrichment, and systematically reviews recent research progress on efficient isolation methods based on affinity interactions. Developmental prospects of exosome isolation and enrichment directions are analyzed with the aim of providing a reference for the construction and use of new exosome-isolation strategies.

Mesenchymal stem cell exosomes therapy for the treatment of traumatic brain injury: mechanism, progress, challenges and prospects

Traumatic brain injury (TBI) is a heterogeneous disease characterized by brain damage and functional impairment caused by external forces. Under the influence of multiple mechanisms, TBI can cause synaptic dysfunction, protein aggregation, mitochondrial dysfunction, oxidative stress, and neuroinflammatory cascade reactions, resulting in a high disability and mortality rate for patients and a heavy burden on families and society. Exosomes are cell-derived vesicles that encapsulate a variety of molecules, including proteins, lipids, mRNAs, and other small biomolecules. Among these, exosomes derived from mesenchymal stem cells (MSCs) have garnered significant attention owing to their therapeutic potential in the nervous system, offering broad clinical applicability. Recent studies have demonstrated that MSC-derived exosome injections in traumatic brain injury models effectively mitigate local inflammatory damage and promote nerve regeneration following injury. Owing to their small size, challenging replication, ease of preservation, and low immunogenicity, MSC exosomes are emerging as a promising therapeutic strategy for traumatic brain injury. This review explores the pathogenesis of traumatic brain injury, the underlying mechanisms of MSC exosome action, and the potential clinical applications of MSC exosomes in the treatment of traumatic brain injury.

Honeycomb-Shaped Supermacroporous Adsorbent Integrating Size-Exclusion and Selective Chemisorption Enables High-Efficiency Extraction and Analysis of Exosomes from Plasma

As cell secretions, exosomes play an important role in disease diagnosis, but the extraction of high-purity exosomes from body fluids faces great challenges. To address this issue, this work creates an excellently selective adsorbent by modifying the zwitterionic polymer carrying choline phosphate on the surface of honeycomb-shaped supermacroporous silica, which integrates chemisorption and size-exclusion principles. The results indicate that the supermacropore with a thin pore wall allows exosomes to enter and thereby be adsorbed by the polymer via specific multivalent interaction and, meanwhile, excludes large cell debris and microvesicles. Moreover, the amphiphilic polymer can inhibit the adsorption of coexisting proteins. Taking advantage of these properties, the adsorbent can extract higher purity exosomes in a simpler way over "gold standard" ultracentrifugation and normal adsorbents. Furthermore, the in situ lysis of adsorbed exosomes simplifies the subsequent analysis and enhances the sensitivity. Consequently, 422 proteins are identified in the exosomes extracted from healthy human plasma, which is higher than that obtained by ultracentrifugation. For plasma from colorectal cancer patients, 62 upregulated and 165 downregulated proteins are identified and can be used as potential biomarkers. In conclusion, the adsorbent can serve as a platform for the high-efficiency extraction of exosomes in clinical diagnostic research.

Efficient Metabolomics Profiling from Plasma Extracellular Vesicles Enables Accurate Diagnosis of Early Gastric Cancer

Accurate diagnosis of early gastric cancer is valuable for asymptomatic populations, while current endoscopic examination combined with pathological tissue biopsy often encounters bottlenecks for early-stage cancer and causes pain to patients. Liquid biopsy shows promise for noninvasive diagnosis of early gastric cancer; however, it remains a challenge to achieve accurate diagnosis due to the lack of highly sensitive and specific biomarkers. Herein, we propose a protocol combining metabolomics profiling from plasma extracellular vesicles (EVs) and machine learning to identify the metabolomics discrepancies of early gastric cancer individuals from other populations. Efficient metabolomics profiling is achieved by efficient, high-purity, and damage-free plasma EVs separation using elaborately designed nanotrap-structured microparticles (NanoFisher) by taking advantage of stereoscopic interaction and affinity interaction. Significant metabolomics discrepancies are obtained from 150 early gastric cancer (50), benign gastric disease (50), and non-disease control (50) plasma samples. Machine learning enables ideal distinction between early gastric cancer and non-disease control samples with an area under the curve (AUC) of 1.000, achieves an AUC of 0.875-0.975 for differentiating early gastric cancer from benign gastric diseases, and demonstrates an overall accuracy of 92% in directly classifying these three categories. The plasma EV metabolomics profiling enabled by NanoFisher materials, integrated with machine learning, holds considerable promise for broad clinical acceptance, enhancing gastric cancer screening outcomes.

Electric Field-Resistant Bubble-Enhanced Wash-Free Profiling of Extracellular Vesicle Surface Markers

Efficient profiling of circulating extracellular vesicles (EVs) benefits noninvasive cancer diagnosis and therapeutic monitoring, but is technically hampered by tedious isolation, multistep washing, and poor sensitivity. Here, we report multifunctional bubbles that enable self-separation, wash-free, single-step, and ultrasensitive profiling of EV surface markers in plasma samples for early diagnosis and treatment monitoring of lung cancer. In this assay, the buoyancy-dominated bubble is electric field-resistant, allowing EV-responsive release of electroactive probes for electrohydrodynamic nanoshearing force-enhanced hybridization, self-separation from the electrode interface for minimizing noise in electrochemical measurements, and one-step wash-free EV profiling. This assay achieves sensitivity near a single-EV level, shows high specificity against nontarget EVs, and tracks EV phenotypic changes induced by drugs. We further show that this technology can classify plasma samples (n = 111) between cancer patients and noncancer controls with accuracies >95%, enable accurate early diagnosis via machine learning, and monitor pre/post-surgery efficacy with higher accuracy over routine clinical serum markers. This bubble-driven one-step EV assay provides a promising wash-free quantitative tool to enable clinical precision liquid biopsies.

CRISPR-Based Homogeneous Electrochemical Strategy for Near-Zero Background Detection of Breast Cancer Extracellular Vesicles via Fluidity-Enhanced Magnetic Capture Nanoprobe

Precise identification and analysis of multiple protein biomarkers on the surface of breast cancer cell-derived extracellular vesicles (BC-EVs) are of great significance for noninvasive diagnosis of the breast cancer subtypes, but it remains a major challenge owing to their high heterogeneity and low abundance. Herein, we established a CRISPR-based homogeneous electrochemical strategy for near-zero background and ultrasensitive detection of BC-EVs. To realize the high-performance capture and isolation of BC-EVs, fluidity-enhanced magnetic nanoprobes were facilely prepared. After capturing BC-EVs, the AND logic gate-based catalytic hairpin assembly (CHA) and the trans-cleavage activity of CRISPR-Cas12a against the magnetic signal nanoprobes were triggered successively, generating a significant electrochemical signal. Notably, the as-developed metal-mediated magnetic signal nanoprobes could efficiently decrease the background signal by magnetic separation, endowing the method with a high signal-to-noise ratio. Consequently, by ingeniously integrating DNA logic gate-based CRISPR-CHA signal amplification with dual magnetic nanoprobes in a homogeneous electrochemical strategy, precise identification and ultrasensitive detection of BC-EVs was successfully achieved through simultaneous and specific recognition of dual protein markers on the BC-EVs surface. More importantly, this approach could effectively discriminate specific subgroups of BC-EVs in clinical serum samples, which may provide great opportunities for the accurate diagnosis and prognosis evaluation of breast cancer in a noninvasive manner.

Extracellular Vesicles Are Prevalent and Effective Carriers of Environmental Allergens in Indoor Dust

The global incidence of allergic diseases is rising and poses a substantial threat to human health. Allergenic proteins released by various allergenic species play a critical role in the pathogenesis of allergic diseases and have been widely detected in the environmental matrix. However, the release, presence and interaction of environmental allergens with human body remain to be elucidated. In this study, we reported the widespread of allergen-harboring extracellular vesicles (EVs) in indoor dust from 75 households across five provinces in China. Particle size and abundance of EVs were correlated with specific environmental factors. EVs showed long persistence and high resistance to environmental stress. Metagenomics and metaproteomics data revealed that most indoor allergenic species released allergens within the EVs into dust. A higher abundance of allergenic species and their derived EVs was observed in urban areas compared to rural areas. ELISA confirmed the allergenic activity of the EV-associated allergens. Allergens are common components and even markers of EVs, as evidenced by the data compilation of various allergenic species. The proportion of EV-associated allergens varied across species. EVs facilitated allergen entry into epithelial cells. Intranasally administered EVs can be rapidly transported to the lungs and gastrointestinal tract. EV-associated allergens exhibited higher allergenicity compared with non-EV allergens. Our findings elucidate a vesicle pathway through which environmental allergens are released, persist, and trigger allergic responses within EVs.

Tailoring cell-inspired biomaterials to fuel cancer therapy

Cancer stands as a predominant cause of mortality across the globe. Traditional cancer treatments, including surgery, radiotherapy, and chemotherapy, are effective yet face challenges like normal tissue damage, complications, and drug resistance. Biomaterials, with their advantages of high efficacy, targeting, and spatiotemporal controllability, have been widely used in cancer treatment. However, the biocompatibility limitations of traditional synthetic materials have restricted their clinical translation and application. Natural cell-inspired biomaterials inherently possess the targeting abilities of cells, biocompatibility, and immune evasion capabilities. Therefore, cell-inspired biomaterials can be used alone or in combination with other drugs or treatment strategies for cancer therapy. In this review, we first introduce the timeline of key milestones in cell-inspired biomaterials for cancer therapy. Then, we describe the abnormalities in cancer including biophysics, cellular biology, and molecular biology aspects. Afterwards, we summarize the design strategies of cell-inspired antitumor biomaterials. Subsequently, we elaborate on the application of antitumor biomaterials inspired by various cell types. Finally, we explore the current challenges and prospects of cell-inspired antitumor materials. This review aims to provide new opportunities and references for the development of antitumor cell-inspired biomaterials.

Efficient and Rapid Enrichment of Extracellular Vesicles Using DNA Nanotechnology-Enabled Synthetic Nano-Glue

Swift and efficient enrichment and isolation of extracellular vesicles (EVs) are crucial for enhancing precise disease diagnostics and therapeutic strategies, as well as elucidating the complex biological roles of EVs. Conventional methods of isolating EVs are often marred by lengthy and laborious processes. In this study, we introduce an innovative approach to enrich and isolate EVs by leveraging the capabilities of DNA nanotechnology. We have developed a novel multivalent cholesterol-modified paranemic crossover DNA (PX-DNA-chol) construct, which is a four-stranded DNA structure containing adjacent double helices intertwined with their local helix axes parallel and serves as an effective synthetic nano-glue. This construct promotes the rapid coalescence of nanoscale EVs into clusters of micrometer scale, thereby streamlining their enrichment. Utilizing a conventional low-speed centrifuge, this intriguing methodology achieves a rapid concentration of EVs within minutes, bypassing the laborious and high-speed centrifugation steps typically required. The quality of EVs isolated by our technique is comparable to that obtained through ultracentrifugation methods. Given these advancements, our PX-DNA-chol-facilitated EVs enrichment protocol is poised to advance the field of EVs research, providing a robust and accessible tool for in-depth studies of EVs.

Emerging phospholipid-targeted affinity materials for extracellular vesicle isolation and molecular profiling

Extracellular vesicles (EVs) carrying lipids, proteins, nucleic acids and small molecular metabolites have emerged as an attractive paradigm for understanding and interfering physiological and pathological processes. To this end, selective and efficient separation approaches are highly demanded to obtain target EVs from complicated biosamples. With increasing knowledges on EV lipids, recent years have witnessed rapid advances of phospholipid-targeted affinity materials and platforms for high-performance isolation and analysis of EVs. In view of this, this review is contributed to introduce recent progresses in lipid membrane-targeted affinity strategies for EV isolation and molecular detection in biofluids. Affinity ligands including lipids, peptides, small molecules and aptamers and their molecular interactions with lipids are discussed in focus. The design, construction and mechanism of actions of affinity interfaces are summarized. The EV separation performances in complex biosamples and downstream proteomic, lipidomic and metabolic profiling are introduced. Finally, the perspectives and challenges for the development of next-generation phospholipid-targeted EV separation platforms are discussed.

Engineering Peptide-Based Molecular Baits for Targeted Fishing and Protein Profiling of Exosomes as a Liquid Biopsy for Gastrointestinal Adenocarcinoma

High-performance isolation of exosomes as a promising liquid biopsy target is of great importance for both fundamental research and clinical applications. This is, however, challenged by the prevalent heterogeneity of exosomes and the highly complex nature of biosamples. Here, we introduce the use of a CD81-targeting peptide as a building block for tailoring molecular baits for exosome isolation and payload analysis in clinical biofluids. To explore the full potential of multivalent interactions, peptide-functionalized affinity interfaces were covalently engineered with varied assembling topology, flexibility, and local density of the recognition motif. Capable of best fitting the surface conformation of CD81 on highly curved exosome membranes, a dual-layered exosome capture affinity interface (Exo-PepTrap2) with tandem bivalent peptide decoration outperforms the monolayered and the branched multivalent architectures. Enabled by the multivalency-enhanced affinity reaction and antifouling ability, Exo-PepTrap2 achieved a high yield and purity for targeted fishing of exosomes in complex cell culture media and clinical urine samples. By integration of Exo-PepTrap2 isolation with mass spectrometry-based proteomic profiling, differentially expressed proteins were efficiently identified in harvested exosomes as potential biomarkers for gastrointestinal adenocarcinoma. This CD81-targeted tandem peptide-functionalized affinity platform provides a new viewpoint for tailoring multivalency-based affinity interfaces and a versatile tool to explore molecular information in exosomes for precise medicine.

Rapid and unbiased enrichment of extracellular vesicles via a meticulously engineered peptide

Extracellular vesicles (EVs) have garnered significant attention in biomedical applications. However, the rapid, efficient, and unbiased separation of EVs from complex biological fluids remains a challenge due to their heterogeneity and low abundance in biofluids. Herein, we report a novel approach to reconfigure and modify an artificial insertion peptide for the unbiased and rapid isolation of EVs in 20 min with ∼80% recovery in neutral conditions. Moreover, the approach demonstrates exceptional anti-interference capability and achieves a high purity of EVs comparable to standard ultracentrifugation and other methods. Importantly, the isolated EVs could be directly applied for downstream protein and nucleic acid analyses, including proteomics analysis, exome sequencing analysis, as well as the detection of both epidermal growth factor receptor (EGFR) and V-Ki-ras2 Kirsten Rat Sarcoma Viral Oncogene Homologue (KRAS) gene mutation in clinical plasma samples. Our approach offers great possibilities for utilizing EVs in liquid biopsy, as well as in various other biomedical applications.

Preparation of Dysprosium(III)-Metal Organic Framework Nanofiber for Exosome Capture and Biomarker Discovery toward Liver Disease

As an emerging source for liquid biopsy, exosomes hold significant promise for clinical diagnosis. However, commonly used exosome isolation methods (e.g., ultracentrifugation) suffer from low throughput for a large number of clinical samples. Herein, a dysprosium-metal organic framework was synthesized and doped with nanofibers by electrospinning for efficient capture of exosomes from body fluid. With the integration of multichannel of pipet or robot automatic workstation, high throughput exosome isolation can be achieved with clinical samples with high reproducibility. To evaluate the clinical value of the developed method, urinary exosomes were enriched from 34 liver disease samples of different stages for the profiling of metabolites by mass spectrometry. The results showed that HCC, cirrhosis, and healthy controls can be significantly differentiated by the Random Forest classification model. The dysprosium-metal organic framework has promising applications in exosome-based liquid biopsy for large-scale clinical disease diagnosis.

DNA Nanomaterial-Empowered Surface Engineering of Extracellular Vesicles

Extracellular vesicles (EVs) are cell-secreted biological nanoparticles that are critical mediators of intercellular communication. They contain diverse bioactive components, which are promising diagnostic biomarkers and therapeutic agents. Their nanosized membrane-bound structures and innate ability to transport functional cargo across major biological barriers make them promising candidates as drug delivery vehicles. However, the complex biology and heterogeneity of EVs pose significant challenges for their controlled and actionable applications in diagnostics and therapeutics. Recently, DNA molecules with high biocompatibility emerge as excellent functional blocks for surface engineering of EVs. The robust Watson-Crick base pairing of DNA molecules and the resulting programmable DNA nanomaterials provide the EV surface with precise structural customization and adjustable physical and chemical properties, creating unprecedented opportunities for EV biomedical applications. This review focuses on the recent advances in the utilization of programmable DNA to engineer EV surfaces. The biology, function, and biomedical applications of EVs are summarized and the state-of-the-art achievements in EV isolation, analysis, and delivery based on DNA nanomaterials are introduced. Finally, the challenges and new frontiers in EV engineering are discussed.

Extracellular Vesicle Preparation and Analysis: A State-of-the-Art Review

In recent decades, research on Extracellular Vesicles (EVs) has gained prominence in the life sciences due to their critical roles in both health and disease states, offering promising applications in disease diagnosis, drug delivery, and therapy. However, their inherent heterogeneity and complex origins pose significant challenges to their preparation, analysis, and subsequent clinical application. This review is structured to provide an overview of the biogenesis, composition, and various sources of EVs, thereby laying the groundwork for a detailed discussion of contemporary techniques for their preparation and analysis. Particular focus is given to state-of-the-art technologies that employ both microfluidic and non-microfluidic platforms for EV processing. Furthermore, this discourse extends into innovative approaches that incorporate artificial intelligence and cutting-edge electrochemical sensors, with a particular emphasis on single EV analysis. This review proposes current challenges and outlines prospective avenues for future research. The objective is to motivate researchers to innovate and expand methods for the preparation and analysis of EVs, fully unlocking their biomedical potential.

Celastrol nano-emulsions selectively regulate apoptosis of synovial macrophage for alleviating rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune inflammation. Excessive proliferation and inadequate apoptosis of synovial macrophages are the crucial events of RA. Therefore, delivering therapeutic molecules to synovial macrophages specifically to tackle apoptotic insufficiency probably can be an efficient way to reduce joint inflammation and bone erosion. Based on the characteristics of dextran sulphate (DS) specifically binding scavenger receptor A (SR-A) on macrophage and celastrol (CLT) inducing apoptosis, we designed synovial macrophage-targeted nano-emulsions encapsulated with CLT (SR-CLTNEs) and explored their anti-RA effect. After intravenous injection, fluorescence-labelled SR-CLTNEs successfully targeted inflammatory joints and synovial macrophages in a mouse model of RA, with the macrophage targeting efficiency of SR-CLTNEs, CLTNEs and free DID was 20.53%, 13.93% and 9.8%, respectively. In vivo and in vitro studies showed that SR-CLTNEs effectively promoted the apoptosis of macrophages, reshaped the balance between apoptosis and proliferation, and ultimately treated RA in a high efficiency and low toxicity manner. Overall, our work demonstrates the efficacy of using SR-CLTNEs as a novel nanotherapeutic approach for RA therapy and the great translational potential of SR-CLTNEs.

Choline Phosphate-Grafted Nanozymes as Universal Extracellular Vesicle Probes for Bladder Cancer Detection

Urinary extracellular vesicles (uEVs) are regarded as highly promising liquid-biopsy biomarkers for the early diagnosis and prognosis of bladder cancer (BC). However, detection of uEVs remains technically challenging owing to their huge heterogeneity and ultralow abundance in real samples. We herein present a choline phosphate-grafted platinum nanozyme (Pt@CP) that acts as a universal EV probe for the construction of a high-throughput and high-sensitivity immunoassay, which allowed multiplex profiling of uEV protein markers for BC detection. With the Pt@CP-based immunoassays, three uEV protein markers (MUC-1, CCDC25, and GLUT1) were identified for BC, by which the BC cases (n = 48), cystitis patients (n = 27), and healthy donors (n = 24) were discriminated with high clinical sensitivity and specificity (area under curve = 98.3%). For the BC cases (n = 9) after surgery, the Pt@CP-based immunoassay could report the postoperative residual tumor that cannot be observed by cystoscopy, which is clinically significant for assessing BC recurrence. This work provides generally high sensitivity for EV detection, facilitating the discovery and clinical use of EV-based biomarkers.

Buoyant Metal-Organic Framework Corona-Driven Fast Isolation and Ultrasensitive Profiling of Circulating Extracellular Vesicles

Accurately assaying tumor-derived circulating extracellular vesicles (EVs) is fundamental in noninvasive cancer diagnosis and therapeutic monitoring but limited by challenges in efficient EV isolation and profiling. Here, we report a bioinspired buoyancy-driven metal-organic framework (MOF) corona that leverages on-bubble coordination and dual-encoded surface-enhanced Raman scattering (SERS) nanotags to streamline rapid isolation and ultrasensitive profiling of plasma EVs in a single assay for cancer diagnostics. This integrated bubble-MOF-SERS EV assay (IBMsv) allows barnacle-like high-density adhesion of MOFs on a self-floating bubble surface to enable fast isolation (2 min, near 90% capture efficiency) of tumor EVs via enhanced EV-MOF binding. Also, IBMsv harnesses four-plexed SERS nanotags to profile the captured EV surface protein markers at a single-particle level. Such a sensitive assay allows multiplexed profiling of EVs across five cancer types, revealing heterogeneous EV surface expression patterns. Furthermore, the IBMsv assay enables cancer diagnosis in a pilot clinical cohort (n = 55) with accuracies >95%, improves discrimination between cancer and noncancer patients via an algorithm, and monitors the surgical treatment response from hepatocellular carcinoma patients. This assay provides a fast, sensitive, streamlined, multiplexed, and portable blood test tool to enable cancer diagnosis and response monitoring in clinical settings.

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.

Isolation and Enrichment of Extracellular Vesicles with Double-Positive Membrane Protein for Subsequent Biological Studies

The isolation and enrichment of specific extracellular vesicle (EV) subpopulations are essential in the context of precision medicine. However, the current methods predominantly rely on a single-positive marker and are susceptible to interference from soluble proteins or impurities. This limitation represents a significant obstacle to the widespread application of EVs in biological research. Herein, a novel approach that utilizes proximity ligation assay (PLA) and DNA-RNA hybridization are proposed to facilitate the binding of two proteins on the EV membrane in advance enabling the isolation and enrichment of intact EVs with double-positive membrane proteins followed by using functionalized magnetic beads for capture and enzymatic cleavage for isolated EVs release. The isolated subpopulations of EVs can be further utilized for cellular uptake studies, high-throughput small RNA sequencing, and breast cancer diagnosis. Hence, developing and implementing a specialized system for isolating and enriching a specific subpopulation of EVs can enhance basic and clinical research in this field.

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.