ExoSD chips for high-purity immunomagnetic separation and high-sensitivity detection of gastric cancer cell-derived exosomes

"Sample-in, result-out" liquid biopsy chip based on immunomagnetic separation and CRISPR detection for multiplex analysis of exosomal microRNAs

Multiplex analysis of exosomal microRNAs (miRNAs) plays an important role in noninvasive early disease diagnosis. However, the complexity of the testing process has hindered its clinical application. Here, we proposed an integrated chip for the detection of eight exosomal miRNAs in serum which can achieve "sample in, result out" detection. We developed an immunomagnetic isolation system based on CD63 aptamers (IISA) for separation of serum exosomes. The system was combined with immiscible filtration assisted by surface tension (IFAST) to remove impurities. Bubble mixing was applied to ensure adequate binding or cleavage of exosomes to magnetic beads. CRISPR detection technology was utilized to allow for effective detection of seven hepatocellular carcinoma (HCC)-related miRNA targets. Based on the test of clinical samples, the chip can achieve 78 % exosome capture efficiency and 55 % recovery, and simultaneously detect eight targets within 1 h. This chip could be applied as a robust and cost-effective tool for cancer diagnosis and monitoring of cancer stages.

Direct isolation of multiple types of circulating tumor cells from undiluted human blood using cascaded viscoelastic microfluidics

Circulating tumor cells (CTCs) are rare cells detaching from metastasis or primary tumor and flowing into bloodstream, which has been a promising biomarker for non-invasive cancer monitoring and diagnosis. Although CTC separating techniques have been widely reported, few platforms practically realize high-throughput and precise isolation of multiple types of CTCs directly from undiluted human blood due to complex flow behavior and interference from high concentration of blood cells. Herein, we present a rapid and label-free cascaded viscoelastic microfluidics (CVEM) composed of blood cells depletion module (BCDM) and CTCs isolation module (CIM). BCDM is used to filter out blood cells from samples, and remaining two types of CTCs (A549 and MCF-7) are isolated in CIM. To systematically reveal the separation mechanism, particle trajectory prediction model including criterion of crossing interface and particle dynamics equation is constructed, and the theoretical results are verified by polystyrene (PS) particle separation experiments. Further, the performance of CVEM is tested with four PS particles mixture solution and human blood spiked with A549 and MCF-7, respectively. 1 mL undiluted blood can be processed within 40 min, and both types of CTCs have high purity (≥81.27%) and recovery rate (≥82.15%). CVEM represents a powerful platform for sorting multiple types of CTCs from directly collected blood, demonstrating significant clinical application potential. Furthermore, particle trajectory prediction model provides a solid theoretical basis for optimizing viscoelastic microfluidics (VEM), and permits rapid iterative design according to different separating requirements, thereby realizing the flexible extension of VEM to other fields.

An integrated microfluidic chip for synchronous drug loading, separation and detection of plasma exosomes

Exosomes have gained increasing attention as robust, biocompatible carriers for targeted therapy. However, current techniques for exosome drug loading suffer from low drug loading efficiency and substantial exosome loss during repeated purification and quantification processes. Here, we present an integrated microfluidic chip (IMC) that streamlines drug loading, separation, and electrochemical detection of exosomes from plasma in a single device. In this design, the three-dimensional (3D) macroporous scaffold and the magnetoresponsive electrode are successfully assembled into the modeling microchip, playing the functions of "3D chaotic flow mixer", "magnetic separator" and "electrochemical detector". When plasma, doxorubicin (DOX), boron clusters and immunomagnetic nanoprobes (IMPs) are simultaneously injected into the IMC, the exosomes are loaded with DOX-boron cluster (EDB) complexes and synchronously recognized by IMPs in the "3D chaotic flow mixer". Our strategy exhibits high DOX loading efficiency owing to the superchaotropic effect of boron clusters and enhanced immunolabeling efficiency by the thorough mixing of the 3D scaffold. Meanwhile, the novel magnetoresponsive electrode enables magnetic separation and real-time, enzyme-linked immunoelectrochemical quantification of exosomes, thereby simplifying the workflow from drug loading to quantification. The resulting EDB in combination with magnetic hyperthermia achieves up to 90% cell-killing efficiency against DOX-resistant breast cancer cells. Overall, our system could simultaneously realize the enhanced DOX loading into exosomes, efficient magnetic immunoseparation of exosomes, and sensitive electrochemical quantification of exosomes, offering a promising approach for autologous exosome-based drug delivery for cancer treatment.

Isolation Techniques of Micro/Nano-Scaled Species for Biomedical Applications

Isolation of micro/nano-scaled bioparticles, such as circulating tumor cells (CTCs), exosomes, bacteria, white blood cells (WBCs), platelets, and viruses, from the sample is essential for cancer diagnosis and treatment, preventing bacterial infections, and monitoring human health. Numerous separation techniques, including magnetophoresis, dielectrophoresis, acoustophoresis, optophoresis, and fluorescence-activated sorting (FAS) have been developed to isolate the target bioparticles from complex samples accurately. However, these active methods usually rely on sophisticated instruments which are expensive and bulky. Passive platforms with high throughput, low cost, and small volume have gradually become alternative methods. Alongside this context, this review paper is no longer confined to one specific category of isolation techniques, advanced systems that have been developed in recent years are comprehensively introduced. Characteristics and limitations of each technology are discussed according to the critical performance parameters including purity, recovery rate, throughput, resolution, size, and convenience. Specific biomedical applications of separation techniques are summarized to provide practical implications for disease diagnosis, treatment, and mechanism research. This review also addresses the current challenges, potential solutions, and prospects in this field, laying the foundation for further optimization, innovation, and cross-integration of isolation techniques in the future.

Integration of acoustic, optical, and electrical methods in picoliter droplet microfluidics for rare particles enrichment

Rare particle enrichment plays a pivotal role in advancing numerous scientific research areas and industrial processes. Traditional enrichment methods encounter obstacles such as low efficiency, high cost, and complexity. Acoustic focusing, optical fiber detection, and electrical manipulation have shown potential in microfluidics for particle manipulation and analysis. This study pioneers the integration of the acoustic, optical, and electrical units to overcome the traditional limitations. The cooperative dynamics of acoustic and flow focusing are explored. The optical fibers with an enhanced detection algorithm greatly boost optical detection sensitivity. Furthermore, the droplet charging to enhance the tip charging phenomenon is complemented and validated. The detection and sorting accuracy of enriching large-size H22 cells reached 99.8% and 99.3%, respectively, with the target cell concentration increased by nearly 86-fold. Our work significantly enhances detection sensitivity and particle manipulation accuracy, ultimately offering a robust and reliable solution for generating droplets to enrich rare particles.

The Roles of Exosomes in Anti-Cancer Drugs

BACKGROUND

Cancer is an escalating global health issue, with rising incidence rates annually. Chemotherapy, a primary cancer treatment, often exhibits low tumor-targeting efficiency and severe side effects, limiting its effectiveness. Recent research indicates that exosomes, due to their immunogenicity and molecular delivery capabilities, hold significant potential as drug carriers for tumor treatment.

METHODS

This review summarizes the current status, powerful therapeutic potential, and challenges of using exosomes for the treatment of tumors.

RESULTS

Exosomes are crucial in tumor diagnosis, onset, and progression. To improve the efficacy of exosome-based treatments, researchers are exploring various biological, physical, and chemical approaches to engineer exosomes as a new nanomedicine translational therapy platform with broad and alterable therapeutic capabilities. Numerous clinical trials are currently underway investigating the safety and tolerability of exosomes carrying drugs to specific sites for the treatment of tumors.

CONCLUSIONS

Exosomes can be engineered as carriers to deliver therapeutic molecules to specific cells and tissues, offering a novel approach for disease treatment.

Enhancing Analysis of Extracellular Vesicles by Microfluidics

Extracellular vesicles (EVs) play crucial roles in intercellular communication and hold great promise as biomarkers for noninvasive disease diagnosis. Intensive research efforts have been devoted to discovering the EV subpopulations responsible for specific functions or with enhanced effectiveness as disease markers, through extensive EV purification and content analysis. However, their high heterogeneity in size and cargo composition poses significant challenges for reaching such goals. Isolation methods like ultracentrifugation and size-exclusion chromatography, as well as content analysis approaches like polymerase chain reaction and enzyme-linked immunosorbent assay, have made significant contributions to improving our understanding of EV biology. Nonetheless, these methods face limitations in isolation efficiency, EV purity, and detection sensitivity and specificity due to issues like large sample consumption, unsatisfactory purity, and insufficient resolution in EV subtyping. Microfluidic technology presents promising solutions to these challenges, leveraging their intrinsic capabilities in precise flow and external energy field manipulation, sample compartmentalization, and signal enhancement at the micro- and nanoscale. Hence, this review summarizes the recent developments in microfluidics-enabled EV analysis, paying special attention to the unique microfluidic features exploited. Strategies such as viscoelastic and inertial flow, fluid mixing, and external-field-assisted approaches in improving EV purification, as well as compartmentalization and micro/nanostructures for enhancing EV detection, are examined. Furthermore, the current limitations and potential future directions are discussed to inspire advancements in this rapidly developing field.

Ultrasensitive Detection of Extracellular Vesicles Based on Metal-Organic Framework DNA Biobarcodes Triggered G-Quadruplex Coupled with Rolling Circle Amplification Assay

Extracellular vesicles (EVs), as liquid biopsy markers for accurate tumor diagnosis, are considered to hold great promise. However, effectively isolating and sensitively detecting EVs with convenience still face challenges. Herein, we propose a highly sensitive and specific platform for EV detection by integrating a metal-organic framework (MOF)-based DNA biobarcodes strategy with a rolling circle amplification (RCA)/G-quadruplex system. In this study, first, Zr-MOFs act as signal converters by comodification with DNA barcodes and antibodies, converting and amplifying the abundance of EVs into DNA barcodes. Second, the released DNA can trigger RCA, followed by G-quadruplex formation to further amplify the signal. Consequently, this approach significantly enhances the sensitivity for EV biomarker detection, achieving a low limit of detection of 100 EVs mL-1. Furthermore, the strategy offers high sensitivity, specificity, accuracy, and simplicity, highlighting its potential for clinical applications in noninvasive EV detection.

EV-Lev: extracellular vesicle isolation from human plasma using microfluidic magnetic levitation device

Biological nanomaterials have unique magnetic and density characteristics that can be employed to isolate them into subpopulations. Extracellular nanovesicles (EVs) are crucial for cellular communication; however, their isolation poses significant challenges due to their diverse sizes and compositions. We present EV-Lev, a microfluidic magnetic levitation technique for high-throughput, selective isolation of small EVs (<200 nm) from human plasma. EV-Lev overcomes the challenges posed by the subtle buoyancy characteristics of EVs, whose small size and varied densities complicate traditional magnetic levitation techniques. It employs antibody-coated polymer beads of varying densities, integrating immuno-affinity and microfluidics to isolate EVs from sub-milliliter plasma volumes efficiently. It facilitates rapid, simultaneous sorting of EV subpopulations based on surface markers, such as CD9, CD63, and CD81, achieving high yield and purity. Subsequent size and morphology analyses confirmed that the isolated EVs maintain their structural integrity. EV-Lev could help uncover the cargo and function of EV subpopulations associated with multiple diseases including cancer, infectious diseases and help to discover potential biomarkers in small volume samples, while offering a portable, cost-effective, and straightforward assay scheme.

Cost-effective microfluidic flow cytometry for precise and gentle cell sorting

Microfluidic flow cytometry (MFCM) is considered to be an effective substitute for traditional flow cytometry, because of its advantages in terms of higher integration, smaller device size, lower cost, and higher cell sorting activity. However, MFCM still faces challenges in balancing parameters such as sorting throughput, viability, sorting efficiency, and cost. Here, we demonstrate a cost-effective and high-performance microfluidic cytometry cell sorting system, along with a customized microfluidic chip that integrates hydrodynamic focusing, droplet encapsulation, and sorting for precise cell manipulation. An innovative photon incremental counting-based fluorescence detection method is proposed, which requires only one-fiftieth of the data compared to traditional methods. This significantly simplifies the structure of the system and substantially reduces costs. The system exhibits detection recoveries exceeding 95% across sample solution flow rates ranging from 10 to 80 μL min-1. Moreover, it accurately achieves individual droplet deflections at a droplet generation frequency of 1600 Hz. Ultimately, our cell sorting system offers an impressive sorting efficiency of 90.7% and a high cell viability of 94.3% when operating at a droplet generation frequency of 1316 Hz, highlighting its accuracy and gentleness throughout the entire process. Our work will enhance advances in the life sciences, thereby creating a boom in great applications in single-cell cloning, single-cell analysis, drug screening, etc.

Exosomal ncRNAs in liquid biopsies for lung cancer

Exosomal non-coding RNAs (ncRNAs) have become essential contributors to advancing and treating lung cancers (LCs). The development of liquid biopsies that utilize exosomal ncRNAs (exo-ncRNAs) offers an encouraging method for diagnosing, predicting, and treating LC. This thorough overview examines the dual function of exo-ncRNAs as both indicators for early diagnosis and avenues for LC treatment. Exosomes are tiny vesicles secreted by various cells, including cancerous cells, enabling connection between cells by delivering ncRNAs. These ncRNAs, which encompass circular RNAs, long ncRNAs, and microRNAs, participate in the modulation of gene expression and cellular functions. In LC, certain exo-ncRNAs are linked to tumour advancement, spread, and treatment resistance, positioning them as promising non-invasive indicators in liquid biopsies. Additionally, targeting these ncRNAs offers potential for innovative treatment approaches, whether by suppressing harmful ncRNAs or reinstating the activity of tumour-suppressing ones. This review emphasizes recent developments in the extraction and analysis of exo-ncRNAs, their practical applications in LC treatment, and the challenges and prospects for translating these discoveries into clinical usage. Through this detailed examination of the current state of the art, we aim to highlight the significant potential of exo-ncRNAs for LC diagnostics and treatments.

Microfluidic-based electrically driven particle manipulation techniques for biomedical applications

Microfluidic chips exhibit unique advantages in both economy and rapidity, particularly for the separation and detection of biomolecules. In this review, we first introduced the mechanisms of several electrically driven methods, such as electrophoresis, dielectrophoresis, electro-wetting and electro-rotation. We then discussed in detail the application of these methods in nucleic acid analysis, protein manipulation and cell treatment. In addition, we outlined the considerations for material selection, manufacturing processes and structural design of microfluidic chips based on electrically driven mechanisms.

A stepwise multi-stage continuous dielectrophoresis separation microfluidic chip with microfilter structures

The separation of target microparticles using microfluidic systems owns extensive applications in biomedical, chemical, and materials science fields. Integration of microfluidic sorting systems employing dielectrophoresis (DEP) technology has been widely investigated. However, enhancing separation efficiency, purity, stability, and integration remains a pressing issue. This study proposes a stepwise multi-stage continuous DEP separation microfluidic chip with a microfilter structure. By leveraging a stepwise electrode configuration, a gradient electric field is generated to drive target microparticles along the electric field gradient, thereby enhancing separation efficiency. Innovative integration of a microfilter structure facilitates simultaneous filtration and improves flow field distribution, thus enhancing system stability. Through the synergistic effect of stepwise electrodes and the microfilter structure, superior coupling of electric and flow fields is achieved, consequently improving the sorting purity, separation efficiency, and system stability of the DEP-based microfluidic sorting system. Validation through simulation and separation of polystyrene microspheres demonstrates the excellent particle separation performance of the proposed system. It evidently shows potential for seamless extension to various biological microparticle sorting applications, harboring significant prospects in the biomedical domain field.

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.

Increasing the sensitivity and accuracy of detecting exosomes as biomarkers for cancer monitoring using optical nanobiosensors

The advancement of nanoscience and material design in recent times has facilitated the creation of point-of-care devices for cancer diagnosis and biomolecule sensing. Exosomes (EXOs) facilitate the transfer of bioactive molecules between cancer cells and diverse cells in the local and distant microenvironments, thereby contributing to cancer progression and metastasis. Specifically, EXOs derived from cancer are likely to function as biomarkers for early cancer detection due to the genetic or signaling alterations they transport as payload within the cancer cells of origin. It has been verified that EXOs circulate steadily in bodily secretions and contain a variety of information that indicates the progression of the tumor. However, acquiring molecular information and interactions regarding EXOs has presented significant technical challenges due to their nanoscale nature and high heterogeneity. Colorimetry, surface plasmon resonance (SPR), fluorescence, and Raman scattering are examples of optical techniques utilized to quantify cancer exosomal biomarkers, including lipids, proteins, RNA, and DNA. Many optically active nanoparticles (NPs), predominantly carbon-based, inorganic, organic, and composite-based nanomaterials, have been employed in biosensing technology. The exceptional physical properties exhibited by nanomaterials, including carbon NPs, noble metal NPs, and magnetic NPs, have facilitated significant progress in the development of optical nanobiosensors intended for the detection of EXOs originating from tumors. Following a summary of the biogenesis, biological functions, and biomarker value of known EXOs, this article provides an update on the detection methodologies currently under investigation. In conclusion, we propose some potential enhancements to optical biosensors utilized in detecting EXO, utilizing various NP materials such as silicon NPs, graphene oxide (GO), metal NPs, and quantum dots (QDs).

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.

Magnetic Nanoparticle-Based Microfluidic Platform for Automated Enrichment of High-Purity Extracellular Vesicles

Extracellular vesicles (EVs) are available in various biological fluids and have highly heterogeneous sizes, origins, contents, and functions. Rapid enrichment of high-purity EVs remains crucial for enhancing research on EVs in tumors. In this work, we present a magnetic nanoparticle-based microfluidic platform (ExoCPR) for on-chip isolation, purification, and mild recovery of EVs from cell culture supernatant and plasma within 29 min. The ExoCPR chip integrates bubble-driven micromixers and immiscible filtration assisted by surface tension (IFAST) technology. The bubble-driven micromixer enhances the mixing between immunomagnetic beads and EVs, eliminating the need for manual pipetting or off-chip oscillatory incubation. The high-purity EVs were obtained after passing through the immiscible phase interface where hydrophilic or hydrophobic impurities nonspecifically bound to SIMI were removed. The ExoCPR chip had a capture efficiency of 75.8% and a release efficiency of 62.7% for model EVs. We also demonstrated the powerful performance of the ExoCPR in isolating EVs from biological samples (>90% purity). This chip was further employed in clinical plasma samples and showed that the number of GPC3-positive EVs isolated from hepatocellular carcinoma patients was significantly higher than that of healthy individuals. This ExoCPR chip may provide a promising tool for EV-based liquid biopsy and other fundamental research.

Nanocluster/metal-organic framework nanosheet-based confined ECL enhancement biosensor for the extracellular vesicle detection

Gastric cancer (GC) was one of the most common cancers with high mortality. The detection of GC peritoneal metastasis had important significance. In this work, we have developed the novel electrochemiluminescence (ECL) biosensor to detect microRNA in GC extracellular vesicle (EV). Firstly, in situ growth of Cu nanocluster (Cu NC) on the metal-organic frameworks (MOFs) nanosheet was achieved successfully. Due to the confinement effect, Cu NCs in the porous structure of Zn MOF possessed the high quantum yield and good stability. Meanwhile, Zn MOF provided good electrochemical activity for the ECL reaction. Furthermore, the nanosized MOFs did not only act as sensing platform to load Cu NCs and link biomolecules, but also reduce steric hindrance effect for biomolecular recognition. Additionally, Au NPs/MXene and phospholipid layer were prepared and modified on the electrode, which can regulate electron transfer and improve the target recognition efficiency. The Cu NCs/Zn MOF nanosheet-based ECL sensor was employed to detect miRNA-421 from 1 fM to 1 nM with a detection limit of 0.5 fM. Finally, extracellular vesicles form clinic GC patient ascites were extracted and analyzed. The results showed that the constructed biosensor can be used for the GC peritoneal metastasis diagnosis.

Exosome Isolation and Detection: From Microfluidic Chips to Nanoplasmonic Biosensor

Exosomes are becoming more widely acknowledged as significant circulating indicators for the prognosis and diagnosis of cancer. Circulating exosomes are essential to the development and spread of cancer, according to a growing body of research. Using existing technology, characterizing exosomes is quite difficult. Therefore, a direct, sensitive, and targeted approach to exosome detection will aid in illness diagnosis and prognosis. The review discusses the new strategies for exosome isolation and detection technologies from microfluidic chips to nanoplasmonic biosensors, analyzing the advantages and limitations of these new technologies. This review serves researchers to better understand exosome isolation and detection methods and to help develop better exosome isolating and detecting devices for clinical applications.

Isolation and usage of exosomes in central nervous system diseases

BACKGROUND

Exosomes are vesicles secreted by all types of mammalian cells. They are characterized by a double-layered lipid membrane structure. They serve as carriers for a plethora of signal molecules, including DNA, RNA, proteins, and lipids. Their unique capability of effortlessly crossing the blood-brain barrier underscores their critical role in the progression of various neurological disorders. This includes, but is not limited to, diseases such as Alzheimer's, Parkinson's, and ischemic stroke. Establishing stable and mature methods for isolating exosomes is a prerequisite for the study of exosomes and their biomedical significance. The extraction technologies of exosomes include differential centrifugation, density gradient centrifugation, size exclusion chromatography, ultrafiltration, polymer coprecipitation, immunoaffinity capture, microfluidic, and so forth. Each extraction technology has its own advantages and disadvantages, and the extraction standards of exosomes have not been unified internationally.

AIMS

This review aimed to showcase the recent advancements in exosome isolation techniques and thoroughly compare the advantages and disadvantages of different methods. Furthermore, the significant research progress made in using exosomes for diagnosing and treating central nervous system (CNS) diseases has been emphasized.

CONCLUSION

The varying isolation methods result in differences in the concentration, purity, and size of exosomes. The efficient separation of exosomes facilitates their widespread application, particularly in the diagnosis and treatment of CNS diseases.

Engineered Extracellular Vesicles in Wound Healing: Design, Paradigms, and Clinical Application

The severe quality of life and economic burden imposed by non-healing skin wounds, infection risks, and treatment costs are affecting millions of patients worldwide. To mitigate these challenges, scientists are relentlessly seeking effective treatment measures. In recent years, extracellular vesicles (EVs) have emerged as a promising cell-free therapy strategy, attracting extensive attention from researchers. EVs mediate intercellular communication, possessing excellent biocompatibility and stability. These features make EVs a potential tool for treating a plethora of diseases, including those related to wound repair. However, there is a growing focus on the engineering of EVs to overcome inherent limitations such as low production, relatively fixed content, and targeting capabilities of natural EVs. This engineering could improve both the effectiveness and specificity of EVs in wound repair treatments. In light of this, the present review will introduce the latest progress in the design methods and experimental paradigms of engineered EVs applied in wound repair. Furthermore, it will comprehensively analyze the current clinical research status and prospects of engineered EVs within this field.

Magnetic Microbead-Based Herringbone Chip for Sensitive Detection of Human Immunodeficiency Virus

The microfluidic chip-based nucleic acid detection method significantly improves the sensitivity since it precisely controls the microfluidic flow in microchannels. Nonetheless, significant challenges still exist in improving the detection efficiency to meet the demand for rapid detection of trace substances. This work provides a novel magnetic herringbone (M-HB) structure in a microfluidic chip, and its advantage in rapid and sensitive detection is verified by taking complementary DNA (cDNA) sequences of human immunodeficiency virus (HIV) detection as an example. The M-HB structure is designed based on controlling the magnetic field distribution in the micrometer scale and is formed by accumulation of magnetic microbeads (MMBs). Hence, M-HB is similar to a nanopore microstructure, which has a higher contact area and probe density. All of the above is conducive to improving sensitivity in microfluidic chips. The M-HB chip is stable and easy to form, which can linearly detect cDNA sequences of HIV quantitatively ranging from 1 to 20 nM with a detection limit of 0.073 nM. Compared to the traditional herringbone structure, this structure is easier to form and release by controlling the magnetic field, which is flexible and helps in further study. Results show that this chip can sensitively detect the cDNA sequences of HIV in blood samples, demonstrating that it is a powerful platform to rapidly and sensitively detect multiple nucleic acid-related viruses of infectious diseases.

Exosomes: Methods for Isolation and Characterization in Biological Samples

Exosomes are small lipid bilayer-encapsulated nanosized extracellular vesicles of endosomal origin. Exosomes are secreted by almost all cell types and are a crucial player in intercellular communication. Exosomes transmit cellular information from donor to recipient cells in the form of proteins, lipids, and nucleic acids and influence several physiological and pathological responses. Due to their capacity to carry a variety of cellular cargo, low immunogenicity and cytotoxicity, biocompatibility, and ability to cross the blood-brain barrier, these nanosized vesicles are considered excellent diagnostic tools and drug-delivery vehicles. Despite their tremendous potential, the progress in therapeutic applications of exosomes is hindered by inadequate isolation techniques, poor characterization, and scarcity of specific biomarkers. The current research in the field is focused on overcoming these limitations. In this chapter, we have reviewed conventional exosome isolation and characterization methods and recent advancements, their advantages and limitations, persistent challenges in exosome research, and future directions.

MoS2 QDs-MXene heterostructure-based ECL sensor for the detection of miRNA-135b in gastric cancer exosomes

Exosomes play an important role in the proliferation, adhesion and migration of cancer cells. In this study, we have developed a novel electrochemiluminescence (ECL) sensor based on MoS2 QDs-MXene heterostructure and Au NPs@biomimetic lipid layer to detect exosomal miRNA. MoS2 QDs-MXene heterostructure had been prepared as the luminescence probe. Ti3C2Tx MXene nanosheets possessed the large specific surface area, excellent flexibility and superior conductivity. MoS2 QDs on the MXene nanosheets worked as the radiation center to generate strong ECL signal. Meanwhile, Au NPs with biomimetic lipid layer have been modified on the electrode, which retained the lipid dynamics and excellent antifouling property. When miRNA-135b was recognized on the Au NPs@biomimetic lipid layer, MoS2 QDs-MXene heterostructure was linked on the electrode and further extended the outer Helmholtz plane. As a result, the self-luminous Faraday cage-mode sensing system has been used to detect miRNA-135b from 30 fM to 20 nM with a detection limit of 10 fM. Furthermore, gastric cancer exosomal miRNA in the ascites of clinical patients has been detected successfully. The sensing system can be served as a versatile platform with huge application potential in the field of exosome detection.

Artificial intelligence in theranostics of gastric cancer, a review

Gastric cancer (GC) is one of the commonest cancers with high morbidity and mortality in the world. How to realize precise diagnosis and therapy of GC owns great clinical requirement. In recent years, artificial intelligence (AI) has been actively explored to apply to early diagnosis and treatment and prognosis of gastric carcinoma. Herein, we review recent advance of AI in early screening, diagnosis, therapy and prognosis of stomach carcinoma. Especially AI combined with breath screening early GC system improved 97.4 % of early GC diagnosis ratio, AI model on stomach cancer diagnosis system of saliva biomarkers obtained an overall accuracy of 97.18 %, specificity of 97.44 %, and sensitivity of 96.88 %. We also discuss concept, issues, approaches and challenges of AI applied in stomach cancer. This review provides a comprehensive view and roadmap for readers working in this field, with the aim of pushing application of AI in theranostics of stomach cancer to increase the early discovery ratio and curative ratio of GC patients.

Urine biomarkers in cancer detection: A systematic review of preanalytical parameters and applied methods

The aim of this review was to explore the status of urine sampling as a liquid biopsy for noninvasive cancer research by reviewing used preanalytical parameters and protocols. We searched two main health sciences databases, PubMed and Web of Science. From all eligible publications (2010-2022), information was extracted regarding: (a) study population characteristics, (b) cancer type, (c) urine preanalytics, (d) analyte class, (e) isolation method, (f) detection method, (g) comparator used, (h) biomarker type, (i) conclusion and (j) sensitivity and specificity. The search query identified 7835 records, of which 924 unique publications remained after screening the title, abstract and full text. Our analysis demonstrated that many publications did not report information about the preanalytical parameters of their urine samples, even though several other studies have shown the importance of standardization of sample handling. Interestingly, it was noted that urine is used for many cancer types and not just cancers originating from the urogenital tract. Many different types of relevant analytes have been shown to be found in urine. Additionally, future considerations and recommendations are discussed: (a) the heterogeneous nature of urine, (b) the need for standardized practice protocols and (c) the road toward the clinic. Urine is an emerging liquid biopsy with broad applicability in different analytes and several cancer types. However, standard practice protocols for sample handling and processing would help to elaborate the clinical utility of urine in cancer research, detection and disease monitoring.

A Novel Electrochemical Differentiation between Exosomal-RNA of Breast Cancer MCF7 and MCF7/ADR-Resistant Cells

Cancer is considered one of the most burdensome diseases affecting lives and, hence, the economy. Breast cancer is one of the most common types of cancer. Patients with breast cancer are divided into two groups: one group responds to the chemotherapy, and the other group resists the chemotherapy. Unfortunately, the group which resists the chemotherapy is still suffering the pain associated with the severe side effects of the chemotherapy. Therefore, there is a critical need for a method to differentiate between both groups before the administration of the chemotherapy. Exosomes, the recently discovered nano-vesicles, are often used as cancer diagnostic biomarkers as their unique composition allows them to represent their parental cells, which makes them promising indicators for tumor prognosis. Exosomes contain proteins, lipids, and RNA that exist in most body fluids and are expelled by multiple cell types, including cancer cells. Furthermore, exosomal RNA has been significantly used as a promising biomarker for tumor prognosis. Herein, we have developed an electrochemical system that could successfully differentiate between MCF7 and MCF7/ADR depending on the exosomal RNA. The high sensitivity of the proposed electrochemical assay opens the door for further investigation that will address the other type of cancer cells.

Toward Personalized Nanomedicine: The Critical Evaluation of Micro and Nanodevices for Cancer Biomarker Analysis in Liquid Biopsy

Liquid biopsy for the analysis of circulating cancer biomarkers (CBs) is a major advancement toward the early detection of cancer. In comparison to tissue biopsy techniques, liquid biopsy is relatively painless, offering multiple sampling opportunities across easily accessible bodily fluids such as blood, urine, and saliva. Liquid biopsy is also relatively inexpensive and simple, avoiding the requirement for specialized laboratory equipment or trained medical staff. Major advances in the field of liquid biopsy are attributed largely to developments in nanotechnology and microfabrication that enables the creation of highly precise chip-based platforms. These devices can overcome detection limitations of an individual biomarker by detecting multiple markers simultaneously on the same chip, or by featuring integrated and combined target separation techniques. In this review, the major advances in the field of portable and semi-portable micro, nano, and multiplexed platforms for CB detection for the early diagnosis of cancer are highlighted. A comparative discussion is also provided, noting merits and drawbacks of the platforms, especially in terms of portability. Finally, key challenges toward device portability and possible solutions, as well as discussing the future direction of the field are highlighted.

Endogenous Lipid Carriers-Bench-to-Bedside Roadblocks in Production and Drug Loading of Exosomes

Exosomes are cell-derived, nano-sized extracellular vesicles comprising a lipid bilayer membrane that encapsulates several biological components, such as nucleic acids, lipids, and proteins. The role of exosomes in cell-cell communication and cargo transport has made them promising candidates in drug delivery for an array of diseases. Despite several research and review papers describing the salient features of exosomes as nanocarriers for drug delivery, there are no FDA-approved commercial therapeutics based on exosomes. Several fundamental challenges, such as the large-scale production and reproducibility of batches, have hindered the bench-to-bedside translation of exosomes. In fact, compatibility and poor drug loading sabotage the possibility of delivering several drug molecules. This review provides an overview of the challenges and summarizes the potential solutions/approaches to facilitate the clinical development of exosomal nanocarriers.

Magneto-Nanomechanical Array Biosensor for Ultrasensitive Detection of Oncogenic Exosomes for Early Diagnosis of Cancers

Exosomes are a class of nanoscale vesicles secreted by cells, which contain abundant information closely related to parental cells. The ultrasensitive detection of cancer-derived exosomes is highly significant for early non-invasive diagnosis of cancer. Here, an ultrasensitive nanomechanical sensor is reported, which uses a magnetic-driven microcantilever array to selectively detect oncogenic exosomes. A magnetic force, which can produce a far greater deflection of microcantilever than that produced by the intermolecular interaction force even with very low concentrations of target substances, is introduced. This method reduced the detection limit to less than 10 exosomes mL^-1 . Direct detection of exosomes in the serum of patients with breast cancer and in healthy people showed a significant difference. This work improved the sensitivity by five orders of magnitude as compared to that of traditional nanomechanical sensing based on surface stress mode. This method can be applied parallelly for highly sensitive detection of other microorganisms (such as bacteria and viruses) by using different probe molecules, which can provide a supersensitive detection approach for cancer diagnosis, food safety, and SARS-CoV-2 infection.

From Conventional to Microfluidic: Progress in Extracellular Vesicle Separation and Individual Characterization

Extracellular vesicles (EVs) are nanoscale membrane vesicles, which contain a wide variety of cargo such as proteins, miRNAs, and lipids. A growing body of evidence suggests that EVs are promising biomarkers for disease diagnosis and therapeutic strategies. Although the excellent clinical value, their use in personalized healthcare practice is not yet feasible due to their highly heterogeneous nature. Taking the difficulty of isolation and the small size of EVs into account, the characterization of EVs at a single-particle level is both imperative and challenging. In a bid to address this critical point, more research has been directed into a microfluidic platform because of its inherent advantages in sensitivity, specificity, and throughput. This review discusses the biogenesis and heterogeneity of EVs and takes a broad view of state-of-the-art advances in microfluidics-based EV research, including not only EV separation, but also the single EV characterization of biophysical detection and biochemical analysis. To highlight the advantages of microfluidic techniques, conventional technologies are included for comparison. The current status of artificial intelligence (AI) for single EV characterization is then presented. Furthermore, the challenges and prospects of microfluidics and its combination with AI applications in single EV characterization are also discussed. In the foreseeable future, recent breakthroughs in microfluidic platforms are expected to pave the way for single EV analysis and improve applications for precision medicine.

Prostate cancer extracellular vesicle digital scoring assay - a rapid noninvasive approach for quantification of disease-relevant mRNAs

Optimizing outcomes in prostate cancer (PCa) requires precision in characterization of disease status. This effort was directed at developing a PCa extracellular vesicle (EV) Digital Scoring Assay (DSA) for detecting metastasis and monitoring progression of PCa. PCa EV DSA is comprised of an EV purification device (i.e., EV Click Chip) and reverse-transcription droplet digital PCR that quantifies 11 PCa-relevant mRNA in purified PCa-derived EVs. A Met score was computed for each plasma sample based on the expression of the 11-gene panel using the weighted Z score method. Under optimized conditions, the EV Click Chips outperformed the ultracentrifugation or precipitation method of purifying PCa-derived EVs from artificial plasma samples. Using PCa EV DSA, the Met score distinguished metastatic (n = 20) from localized PCa (n = 20) with an area under the receiver operating characteristic curve of 0.88 (95% CI:0.78-0.98). Furthermore, longitudinal analysis of three PCa patients showed the dynamics of the Met scores reflected clinical behavior even when disease was undetectable by imaging. Overall, a sensitive PCa EV DSA was developed to identify metastatic PCa and reveal dynamic disease states noninvasively. This assay may complement current imaging tools and blood-based tests for timely detection of metastatic progression that can improve care for PCa patients.

Tumor-Derived Biomarkers in Liquid Biopsy of Glioblastoma

There is a pressing clinical need for minimally invasive liquid biopsies to supplement imaging in the treatment of glioblastoma. Diagnostic imaging is often difficult to interpret and the medical community is divided on distinguishing among complete response, partial response, stable disease, and progressive disease. A minimally invasive liquid biopsy would supplement imaging and clinical findings and has the capacity to be helpful in several ways: 1) diagnosis, 2) selection of patients for specific treatments, 3) tracking of treatment response, and 4) prognostic value. The liquid biome is the combination of biological fluids including blood, urine, and cerebrospinal fluid that contain small amounts of tumor cells, DNA/RNA coding material, peptides, and metabolites. Within the liquid biome, 2 broad categories of biomarkers can exist: tumor-derived, which can be directly traced to the tumor, and tumor-associated, which can be traced back to the response of the body to disease. Although tumor-associated biomarkers are promising liquid biopsy candidates, recent advances in biomarker enrichment and detection have allowed concentration on a new class of biomarker: tumor-derived biomarkers. This review focuses on making the distinction between the 2 biomarker categories and highlights promising new direction.

Recent developments in isolating methods for exosomes

Exosomes are the smallest extracellular vesicles that can be released by practically all cell types, and range in size from 30 nm to 150 nm. As the major marker of liquid biopsies, exosomes have great potential for disease diagnosis, therapy, and prognosis. However, their inherent heterogeneity, the complexity of biological fluids, and the presence of nanoscale contaminants make the isolation of exosomes a great challenge. Traditional isolation methods of exosomes are cumbersome and challenging with complex and time-consuming operations. In recent years, the emergence of microfluidic chips, nanolithography, electro-deposition, and other technologies has promoted the combination and innovation of the isolation methods. The application of these methods has brought very considerable benefits to the isolation of exosomes such as ultra-fast, portable integration, and low loss. There are significant functional improvements in isolation yield, isolation purity, and clinical applications. In this review, a series of methods for the isolation of exosomes are summarized, with emphasis on the emerging methods, and in-depth comparison and analysis of each method are provided, including their principles, merits, and demerits.

Exosomal circRNAs: Novel biomarkers and therapeutic targets for gastrointestinal tumors

Despite the high prevalence of gastrointestinal tumors, early diagnosis and treatment of these tumors is limited by the lack of effective and specific biomarkers and therapeutic targets. Exosomes carry active molecules to mediate cell-to-cell communication, especially in the tumor microenvironment, and are promising biomarkers and therapeutic targets for cancer. Circular RNAs (circRNAs) are stably enriched in exosomes and show a unique circular structure, high stability, conservation, and tissue specificity. Exosomal circRNAs play important roles in regulating cell proliferation, metastasis, angiogenesis, metabolism, and the immune microenvironment of gastrointestinal tumors and exhibit great potential as tumor biomarkers and anti-tumor targets or tools. This review briefly introduces the characteristics and functions of circRNAs and exosomes, and systematically describes the biological roles and mechanisms of exosomal circRNAs in gastrointestinal tumors. This article also summarizes the detection methodology of exosomal circRNAs and discusses their clinical significance as biomarkers and targets for gastrointestinal tumors.

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.

Nickel-Doped Microfluidic Chip for Rapid and Efficient Immunomagnetic Separation and Detection of Breast Cancer Cell-Derived Exosomes

Breast cancer cell-derived exosomes have high potential as biomarkers for continuous biopsies and longitudinal monitoring in breast cancer. However, it is extremely difficult to separate exosomes with high recovery and high purity from complex media, such as urine, plasma, saliva and cell culture supernatants. Here, we designed a flexible and simple microfluidic chip for exosome separation. The capture zone of the chip is a three-dimensional structure of interlaced cylinders doped with nickel powder. Exosomes were separated from cell culture supernatant by the immunomagnetic separation method in continuous flow mode and were detected by fluorescence imaging with high sensitivity. The chip achieved a high exosome recovery rate (> 74%) and purity (> 67%) at an injection rate of 3.6 mL/h. Thus, this chip was demonstrated to be a cutting-edge platform for the separation and detection of exosomes. It could also be applied to separate and detect other types of exosomes, microbubbles and cells.

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.

Integrated microfluidic-SERS for exosome biomarker profiling and osteosarcoma diagnosis

Osteosarcoma is one of the most frequent primary sarcoma of bone among adolescents. Early diagnosis of osteosarcoma is the key factor to achieve high survival rate of patients. Nevertheless, traditional histological biopsy is highly invasive and associated with the risk of arousing tumor spread. Herein, we develop a method integrating microfluidics and surface-enhanced Raman spectroscopy (SERS) to isolate plasma-derived exosomes and profile multiple exosomal biomarkers for the diagnosis of osteosarcoma. The method showed highly efficient isolation of exosomes directly from human plasma and can profile exosomes based on protein biomarkers, with the detection limit down to 2 exosomes per μL. The whole assay can be performed in 5 h and only consumed 50 μL of plasma for one analysis. With the method, we analyzed the level of three protein biomarkers, i.e., CD63, vimentin (VIM) and epithelial cell adhesion molecule (EpCAM), on plasma-derived exosomes from 20 osteosarcoma patients and 20 heathy controls. Significantly higher levels of CD63, VIM and EpCAM were observed on plasma exosomes from the osteosarcoma patients compared to the healthy controls. Based on the level of the exosomal biomarkers, a classification model was built for the rapid diagnosis of osteosarcoma, with the sensitivity, specificity and accuracy of 100%, 90% and 95%, respectively. The proposed method does not require complex operations nor expensive equipment, and has great promise in clinical diagnosis of cancer as a liquid biopsy technique.

A visual and reversible nanoprobe for rapid and on-site determination of hexavalent chromium and lysine based on dual-emission carbon quantum dots coupled with smartphone

A straightforward, largely instrument-free, smartphone-based analytical strategy for hexavalent chromium and lysine (Lys) on-site detection via exploitation of dual-emission carbon quantum dots (DECQDs) has been demonstrated. DECQDs show dual-emission peaks at 439 and 630 nm with the excitation at 375 nm. As a dual-mode detection probe, the fluorescence and ultraviolet adsorption spectra of DECQDs vary with hexavalent chromium concentrations. Most importantly, Lys can restore the fluorescence of the hexavalent chromium added DECQD nanoprobe and change the color of the probe under natural light. At the same time, based on the participation of smartphones, the prepared DECQD probes favor the establishment of visual smart sensors that can also be used for the in-situ detection of targets. The on-site quantitative analysis exhibited a linear range of 5.3-320 μM with a detection limit of 1.6 μM towards Cr(VI) and the differentiation of Lys variation from 1 to 75 mM with a detection limit of 0.3 mM. The probe has been applied for the first time to enable vision-based colorimetric in complex samples such as water, milk and egg. The recoveries of Cr(VI) and Lys in real samples were between 90 and 104%, and the relative standard deviation (RSD) was as low as 0.4%. This work offers new perspectives for fundamental understanding and new design of functional luminescent materials that are applicable for food-safety and rapid and intelligent inspection. A straightforward, large instrument-free, smartphone-based analytical strategy with dual-emission carbon quantum dots was developed for hexavalent chromium and Lys on-site detection via fluorescent and colorimetric twofold readout measure.

Tumor-derived small extracellular vesicles: potential roles and mechanism in glioma

Small extracellular vesicles (SEVs) are extracellular vesicles containing DNA, RNA, and proteins and are involved in intercellular communication and function, playing an essential role in the growth and metastasis of tumors. SEVs are present in various body fluids and can be isolated and extracted from blood, urine, and cerebrospinal fluid. Under both physiological and pathological conditions, SEVs can be released by some cells, such as immune, stem, and tumor cells, in a cytosolic manner. SEVs secreted by tumor cells are called tumor-derived exosomes (TEXs) because of their origin in the corresponding parent cells. Glioma is the most common intracranial tumor, accounting for approximately half of the primary intracranial tumors, and is characterized by insidious onset, high morbidity, and high mortality rate. Complete removal of tumor tissues by surgery is difficult. Chemotherapy can improve the survival quality of patients to a certain extent; however, gliomas are prone to chemoresistance, which seriously affects the prognosis of patients. In recent years, TEXs have played a vital role in the occurrence, development, associated immune response, chemotherapy resistance, radiation therapy resistance, and metastasis of glioma. This article reviews the role of TEXs in glioma progression, drug resistance, and clinical diagnosis.

Sensitive Electrochemical Biosensor for Rapid Screening of Tumor Biomarker TP53 Gene Mutation Hotspot

Rapid and sensitive detection of cancer biomarkers is crucial for cancer screening, early detection, and improving patient survival rate. The present study proposes an electrochemical gene-sensor capable of detecting tumor related TP53 gene mutation hotspots by self-assembly of sulfhydryl ended hairpin DNA probes tagged with methylene blue (MB) onto a gold electrode. By performing a hybridization reaction with the target DNA sequence, the gene-sensor can rearrange the probe's structure, resulting in significant electrochemical signal differences by differential pulse voltammetry. When the DNA biosensor is hybridized with 1 μM target DNA, the peak current response signal can decrease more than 60%, displaying high sensitivity and specificity for the TP53 gene. The biosensor achieved rapid and sensitive detection of the TP53 gene with a detection limit of 10 nmol L-1, and showed good specific recognition ability for single nucleotide polymorphism (SNP) and base sequence mismatches in the TP53 gene affecting residue 248 of the P53 protein. Moreover, the biosensor demonstrated good reproducibility, repeatability, operational stability, and anti-interference ability for target DNA molecule in the complex system of 50% fetal bovine serum. The proposed biosensor provides a powerful tool for the sensitive and specific detection of TP53 gene mutation hotspot sequences and could be used in clinical samples for early diagnosis and detection of cancer.

Glioblastoma Associated Natural Killer Cell EVs Generating Tumour-Specific Signatures: Noninvasive GBM Liquid Biopsy with Self-Functionalized Quantum Probes

Diagnosis of glioblastoma (GBM) poses a recurring struggle due to many factors, including the presence of the blood-brain barrier (BBB) in addition to the significant tumor heterogeneity. Natural killer (NK) cells of the innate immune system are the primary immune surveillance mechanism for GBM and identify GBM tumors without any previous sensitization. The metabolic reprogramming of NK cells during GBM association is expected to be reflected in its extracellular vesicles. Therefore, tracking the activity of NK cell vesicles in circulation (circulating immune vesicles, CIVs) has great potential for accurate GBM diagnosis. However, identification GBM associated CIVs in circulation is immensely challenging as there is no availability of clinically validated GBM-specific circulating biomarkers. Here, we present GBM associated CIV profiling for noninvasive GBM diagnosis. We investigated the feasibility of using the signals derived from GBM associated CIVs as a de novo methodology for GBM diagnosis. An ultrasensitive sensor and a marker-free approach were essential for the detection of rare signals of GBM associated CIVs. For this purpose, we designed GBM ImmunoProfiler platform using scalable ultrafast laser multiphoton ionization mechanism and adopted surface enhanced Raman spectroscopy (SERS) ensuring simultaneous detection of multiple CIV signals to identify GBM. We experimentally demonstrated that GBM associated CIVs carry unique, tumor-specific signals. The features of GBM associated CIVs were explored through machine learning identifying its similarity with GBM patient blood (without cell isolation) using a very small amount of peripheral blood (5 μL) with 96.82% sensitivity and 100% specificity. In addition, we demonstrated that a tumor associated CIV profile can classify between multiple brain cancer types (astrocytoma, oligodendroglioma, and glioblastoma). We also experimentally demonstrated significant variation in the immune checkpoint protein expression (PDL-1 and CTLA-4) between GBM associated CIVs and uninteracted CIVs. Preclinical analysis with serum specimens of GBM patients showed the possibility of using our technology for minimally invasive GBM diagnosis. With clinical validation, our technology has potential to improve GBM diagnostics with a useful, minimally invasive GBM liquid biopsy.

Exosomes as Crucial Players in Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that affects multiple systems. Its clinical manifestation varies across patients, from skin mucosa to multiorgan damage to severe central nervous system involvement. The exosome has been shown to play an important role in the pathogenesis of autoimmune diseases, including SLE. We review the recent knowledge of exosomes, including their biology, functions, mechanism, and standardized extraction and purification methods in SLE, to highlight potential therapeutic targets for SLE.

Exosome-mediated remodeling of the tumor microenvironment: From local to distant intercellular communication

Extracellular vesicles (EVs) are membrane-enveloped nanoscale particles that carry various bioactive signaling molecules secreted by cells. Their biological roles depend on the original cell type from which they are derived and their inclusions. Exosomes, a class of EVs, are released by almost all eukaryotic cell types, including tumor cells. Tumor cell-derived exosomes mediate signal transduction between tumor cells and surrounding non-tumor cells. This intercellular communication actively contributes to the remodeling of the tumor microenvironment (TME) to enable tumor growth, invasion, and metastasis. This review summarizes the latest progress in the exploration of exosome-mediated cell-cell communication implicated in TME remodeling and underlying mechanisms. We focus on the role of cell-cell interactions mediated by tumor cell-derived exosomes in promoting invasion and metastasis, and their potential as a therapeutic intervention target against distant metastasis. We also discuss the clinical translational significance of tumor-derived exosomes for early diagnosis, efficacy and progression evaluations.

Hedgehog-inspired immunomagnetic beads for high-efficient capture and release of exosomes

Exosomes are small extracellular vesicles secreted by cells. They play an important regulatory role in the physiological and pathological processes of the body, and participate in the occurrence and development of many diseases. Although tumor-derived exosomes have been used as biomarkers for cancer detection, it is still a huge challenge to efficiently capture and release functionally complete exosomes. In our research, inspired by the structure of hedgehog burrs, we proposed immunomagnetic hedgehog particles (IMHPs) to efficiently capture and release exosomes. In general, after the assembly of one-dimensional nanostructural TiO2 bundles into hedgehog TiO2 particles with 356.12 ± 38.32 nm spikes, magnetic responsive nanoparticles (Fe3O4, ∼20 nm), an antifouling polyethylene glycol (PEG) component containing a redox responsive disulfide linkage and anti-CD63 antibody were introduced stepwise to functionalize hedgehog particles and generate IMHPs (1.23 ± 0.18 μm). Due to their unique topological structures, exosomes were positively selected with an exosomal marker (CD63) and negatively selected by depleting environmental pollutants (protein precipitates, cell debris) with the nano-spikes. These prepared IMHPs were successfully applied to capture exosomes from MCF-7 cells, with a capture efficiency of 91.70%. Then, tris (2-carboxyethyl) phosphine hydrochloride (TCEP) was used to reduce the disulfide bond to release exosomes, and the release efficiency was up to 82.45%. The exosomes that experienced successive immunomagnetic separation and release well maintained their structural integrity and good bioactivity to promote MCF-7 cell migration, as compared with those exosomes separated by the classic ultracentrifugation approach. These results also indicated that IMHPs would have broad prospects in biomedicine and clinical applications, where highly efficient and non-destructive separation of bio-substances (cells, extracellular vesicles, etc.) is critically required.

Rapid On-Chip Isolation of Cancer-Associated Exosomes and Combined Analysis of Exosomes and Exosomal Proteins

Exosomes are lipid bilayer extracellular vesicles secreted by various types of cells and inherit abundant molecular information from parental cells. Tumor-derived exosomes have been widely recognized as noninvasive biomarkers for early cancer diagnosis and surveillance, but the separation of intact exosomes and detection of exosomal proteins remain challenging. Herein, we proposed a microfluidic chip for specific exosome isolation, integrated with sensitive quantification by a novel PTCDI-aptamer signal switch strategy. To enhance the capture efficiency, an alternating drop-shaped micropillar array was designed to assist the capture of tumor-derived exosomes by Tim4-modified magnetic beads (Tim4 beads) on the chip. Following capture, a chelating agent can easily elute intact exosomes which were further used for profiling exosomal surface proteins by the multiplexed fluorescence turn-on approach. Profiting from the efficient on-chip enrichment of the Tim4 beads and superior fluorescence signal transduction strategy, the detection limit of the analysis platform for HepG2 exosomes is as low as 8.69 × 10³ particles/mL with a wide linear range spanning 6 orders of magnitude. Meanwhile, the proposed platform could recognize subtle changes in protein levels on the exosomal surface from various cell lines. More importantly, this strategy is successfully applied to analyze exosomes in human serum to distinguish liver cancer patients from healthy individuals. Combined analysis of different types of biomarkers on the exosomal membrane surface can greatly improve the accuracy of cancer type identification and disease monitoring. We hope that this convenient, rapid, and sensitive platform may become a powerful tool in the field of exosome analysis and early cancer screening.