Integrated Analysis of Exosomal Protein Biomarkers on Alternating Current Electrokinetic Chips Enables Rapid Detection of Pancreatic Cancer in Patient Blood

From bench to bedside: The evolution of extracellular vesicle diagnostics through microfluidic and paper-based technologies

"Extracellular vesicles (EVs) have emerged as key mediators of intercellular communication and valuable biomarkers for various diseases. However, traditional EV isolation and detection methods often struggle with efficiency, scalability, and purity, limiting their clinical utility. Recent advances in microfluidic and paper-based technologies offer innovative solutions that enhance EV isolation and detection by reducing sample volume, accelerating processing times, and integrating multiple analytical steps into compact platforms. These technologies hold significant promise for advancing point-of-care diagnostics, enabling rapid disease detection, personalized treatment monitoring, and better patient outcomes. For example, early detection of cancer biomarkers through EVs can facilitate timely intervention, potentially improving survival rates, while rapid infectious disease diagnostics can support prompt treatment. Despite their potential, challenges such as standardization, scalability, and regulatory hurdles remain. This review discusses recent advancements in microfluidic and paper-based EV diagnostic technologies, their comparative advantages over traditional methods, and their transformative potential in clinical practice."

Blood-based biomarkers in pancreatic ductal adenocarcinoma: developments over the last decade and what holds for the future- a review

Pancreatic Ductal Adenocarcinoma (PDAC) accounts for a significant burden of global cancer deaths worldwide. The dismal outcomes associated with PDAC can be overcome by detecting the disease early and developing tools that predict response to treatment, allowing the selection of the most optimal treatment. Over the last couple of years, significant progress has been made in the development of novel biomarkers that aid in diagnosis, prognosis, treatment selection, and monitoring response. Blood-based biomarkers offer an alternative to tissue-based diagnosis and offer immense potential in managing PDAC. In this review, we have discussed the advances in blood-based biomarkers in PDAC, such as DNA (mutations and methylations), RNA, protein biomarkers and circulating tumor cells (CTC) over the last decade and also elucidated all aspects of practical implementation of these biomarkers in clinical practice. We have also discussed implementing multiomics utilizing more than one biomarker and targeted therapies that have been developed using these biomarkers.

Exosomal biomarkers: A novel frontier in the diagnosis of gastrointestinal cancers

Gastrointestinal (GI) cancers, which predominantly manifest in the stomach, colorectum, liver, esophagus, and pancreas, accounting for approximately 35% of global cancer-related mortality. The advent of liquid biopsy has introduced a pivotal diagnostic modality for the early identification of premalignant GI lesions and incipient cancers. This non-invasive technique not only facilitates prompt therapeutic intervention, but also serves as a critical adjunct in prognosticating the likelihood of tumor recurrence. The wealth of circulating exosomes present in body fluids is often enriched with proteins, lipids, microRNAs, and other RNAs derived from tumor cells. These specific cargo components are reflective of processes involved in GI tumorigenesis, tumor progression, and response to treatment. As such, they represent a group of promising biomarkers for aiding in the diagnosis of GI cancer. In this review, we delivered an exhaustive overview of the composition of exosomes and the pathways for cargo sorting within these vesicles. We laid out some of the clinical evidence that supported the utilization of exosomes as diagnostic biomarkers for GI cancers and discussed their potential for clinical application. Furthermore, we addressed the challenges encountered when harnessing exosomes as diagnostic and predictive instruments in the realm of GI cancers.

Leveraging dielectrophoresis in inertial flow for versatile manipulation of micro and nanoparticles

The manipulation of micro and nanoparticles has extensive applications in biomedical research, clinical diagnostics, environmental monitoring, drug discovery, and the mining industry. Dielectrophoresis (DEP) utilises nonuniform electric fields to manipulate particles, offering a label-free, high-precision, and non-invasive method for both natural and synthetic particles. DEP manipulation has been well studied in the Stokes flow region with ultra-low Reynolds numbers (Re ≪ 1), where viscous effects dominate. However, its application in the inertial flow regime remains largely unexplored. This study aims to bridge the gap by coupling DEP and inertial flow for the manipulation of particles across micro and nano scales. First, we theoretically analysed the physical coupling of DEP and inertial lift forces along the vertical direction in microchannels, utilising symmetrical interdigitated electrode (IDE) arrays patterned on the top and bottom channel surfaces. We then experimentally investigated how the vertical coupling of DEP and inertial lift forces affects particle lateral focusing properties. The effects of DEP along the vertical direction were leveraged and amplified by the inertial effects along the lateral direction. Finally, we applied DEP in the inertial flow regime for size-based and dielectric property-based separation of particles and cells, as well as nanoparticle focusing and filtration. We believe that leveraging DEP in inertial flow will advance the field by providing a versatile and powerful method for the manipulation of micro and nanoparticles.

Nanomedicine in the Diagnosis and Treatment of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with increasing incidence and mortality rates, highlighting the urgent need for early diagnosis and treatment. However, early diagnosis of PDAC is extremely challenging due to the atypical early symptoms or the absence of noticeable symptoms. As a result, many patients are diagnosed with local metastasis, and even patients who are eligible for surgical resection have a high postoperative recurrence rate. Consequently, chemotherapy remains the primary treatment for PDAC. However, the unique biological characteristics of PDAC not only promote tumor progression and metastasis but also often lead to chemoresistance, a significant barrier to successful treatment. Recently, nanomaterials have garnered significant attention as promising materials for diagnosing and treating PDAC, showing great potential in cancer therapy, imaging, and drug delivery. Novel targeted nanomedicines, which encapsulate chemotherapy drugs and gene therapy products, offer significant advantages in overcoming resistance. These nanomedicines not only provide innovative solutions to the limitations of conventional chemotherapy but also improve the selectivity for cancer cells to enhance therapeutic outcomes. Current research is focused on the development of advanced nanomedicines, such as liposomes, nanotubes, and polymer-lipid hybrid systems, aimed at making chemotherapy more effective and longer lasting. This review provides a detailed overview of various nanomedicines utilized in the diagnosis and treatment of PDAC and outlines future directions for their development and key breakthroughs.

Optical sorting: past, present and future

Optical sorting combines optical tweezers with diverse techniques, including optical spectrum, artificial intelligence (AI) and immunoassay, to endow unprecedented capabilities in particle sorting. In comparison to other methods such as microfluidics, acoustics and electrophoresis, optical sorting offers appreciable advantages in nanoscale precision, high resolution, non-invasiveness, and is becoming increasingly indispensable in fields of biophysics, chemistry, and materials science. This review aims to offer a comprehensive overview of the history, development, and perspectives of various optical sorting techniques, categorised as passive and active sorting methods. To begin, we elucidate the fundamental physics and attributes of both conventional and exotic optical forces. We then explore sorting capabilities of active optical sorting, which fuses optical tweezers with a diversity of techniques, including Raman spectroscopy and machine learning. Afterwards, we reveal the essential roles played by deterministic light fields, configured with lens systems or metasurfaces, in the passive sorting of particles based on their varying sizes and shapes, sorting resolutions and speeds. We conclude with our vision of the most promising and futuristic directions, including AI-facilitated ultrafast and bio-morphology-selective sorting. It can be envisioned that optical sorting will inevitably become a revolutionary tool in scientific research and practical biomedical applications.

Protein profile in urinary extracellular vesicles is a marker of malignancy and correlates with muscle invasiveness in urinary bladder cancer

Urinary Bladder Cancer (UBC) ranks among the most prevalent cancers worldwide, has a high recurrence rate and unpredictable treatment responses. Thus, biomarkers are urgently needed. Extracellular vesicles (EVs) are released from both cancer- and immune cells and provide a snapshot of the originating cell. They are abundant in urine and are therefore candidate biomarkers for UBC. Isolated urinary EVs from 39 UBC patients were compared with EVs from healthy controls, prostate cancer patients and whole urine. Samples were from bladder urine at time of both transurethral resection of the bladder tumour (TURB) and cystectomy, as well as urine taken from the ureter at cystectomy. EVs were isolated by tangential flow filtration and differential ultracentrifugation and their protein composition was detected by Proximity Extension Assay (PEA; Olink, immuno-oncology panel). In UBC patients, the proteomic signature of bladder urine EVs differed from ureter urine EVs from the same individuals, and from bladder urine derived EVs of both healthy and prostate cancer controls. Pairwise comparison was performed with matched whole urine revealing proteins solely detected in isolated vesicles. Additionally, a distinct signature was identified in bladder urine EVs correlating with muscle invasiveness, and a trained classifier could predict UBC with 92 % accuracy. Some differentially expressed proteins, HO-1 and MMP7, were analysed by bead-based flow cytometry, where HO-1 was detected on the EV surface. Taken together, these results strengthen the rationale of using EVs as non-invasive biomarkers and prognostic tools for UBC.

Single step capture and assessment of multiple plasma extracellular vesicle biomarkers in Alzheimer's disease detection

BACKGROUND

Blood tests for Alzheimer's disease (AD) that measure biomarkers related to neuropathology have demonstrated to be useful, minimally-invasive ways to identify patients for screening into clinical trials. While some AD biomarkers can be detected in plasma, greater sensitivity is needed to make plasma AD tests more effective. Extracellular vesicles (EVs) in plasma carry AD-related biomarkers from the brain and could offer a concentrated source of brain-related biomarkers, though the methodological complexities involved in isolating plasma EVs have hampered its validation for clinical use.

OBJECTIVE

To explore the feasibility and effectiveness of developing blood tests for AD utilizing extracellular vesicle-bound protein biomarkers.

METHODS

We developed a simplified method for isolating EVs directly from plasma using an alternating current electrokinetic (ACE) microchip. No sample pretreatment steps were needed. Protein biomarkers on the EVs were detected by adding fluorescent antibodies to the plasma samples before capture by the chip. This allowed measurement of EV biomarker levels directly on the chip.

RESULTS

AD or non-AD control plasma was measured for ten different AD-related biomarkers. EV-associated NCAM1, pTau231, α-synuclein, and TDP-43 levels were able to distinguish a group of 10 AD, 10 mild cognitive impairment (MCI), and 10 non-AD subjects. pTau231 was different between AD and non-AD (p = 0.0300) and α-synuclein differentiated AD from MCI (p = 0.0148).

CONCLUSIONS

This study shows how ACE microfluidic chip technology can help differentiate AD and MCI patients from non-AD controls with clinical relevance. This work also highlights the important diagnostic role of plasma EV biomarkers in neurodegenerative disease.

[The concept of the liquid biopsy in the treatment of malignant eye tumours]

The liquid biopsy is a cutting-edge technique that involves analysing non-solid biological tissues, primarily blood but also ocular fluids, for the presence of cancer cells or fragments of tumour DNA. Unlike traditional biopsies, liquid biopsies are usually minimally invasive and can be performed more frequently, enabling continuous monitoring of disease progression and treatment efficacy. This article (and the associated series of articles) outlines the key developments in liquid biopsy, which include the analysis of circulating tumor DNA (ctDNA), circulating tumor cells (CTC) and exosomal RNA and protein biomarkers. Techniques, such as digital droplet PCR and next-generation sequencing (NGS) have made it possible to detect even very low levels of ctDNA, which is crucial for early cancer detection and monitoring minimal residual disease. The detection of rare CTCs is enhanced by techniques, such as microfluidic devices and immunomagnetic separation. Multiomic approaches, whereby exosomal RNA, protein and ctDNA analyses are combined, help to create a more comprehensive picture of tumour biology, including insights into tumour heterogeneity, potentially leading to better diagnostic and prognostic tools and helping to predict treatment response and resistance. The challenges of liquid biopsy application, which will be described in the following article, include (a) standardization, (b) cost and accessibility, (c) validation and clinical utility. However, the liquid biopsy represents a promising frontier in the application of precision ocular oncology, with ongoing research likely to expand its applications and improve its effectiveness in the coming years.

The new advance of exosome-based liquid biopsy for cancer diagnosis

Liquid biopsy is a minimally invasive method that uses biofluid samples instead of tissue samples for cancer diagnosis. Exosomes are small extracellular vesicles secreted by donor cells and act as mediators of intercellular communication in human health and disease. Due to their important roles, exosomes have been considered as promising biomarkers for liquid biopsy. However, traditional methods for exosome isolation and cargo detection methods are time-consuming and inefficient, limiting their practical application. In the past decades, many new strategies, such as microfluidic chips, nanowire arrays and electrochemical biosensors, have been proposed to achieve rapid, accurate and high-throughput detection and analysis of exosomes. In this review, we discussed about the new advance in exosome-based liquid biopsy technology, including isolation, enrichment, cargo detection and analysis approaches. The comparison of currently available methods is also included. Finally, we summarized the advantages and limitations of the present strategies and further gave a perspective to their future translational use.

Oligo cyc-DEP: On-chip cyclic immunofluorescence profiling of cell-derived nanoparticles

We present a follow-on technique for the cyclic-immunofluorescence profiling of suspension particles isolated using dielectrophoresis. The original lab-on-chip technique ("cyc-DEP" [cyclic immunofluorescent imaging on dielectrophoretic chip]) was designed for the multiplex surveillance of circulating biomarkers. Nanoparticles were collected from low-volume liquid biopsies using microfluidic dielectrophoretic chip technology. Subsequent rounds of cyclic immunofluorescent labeling and quenching were imaged and quantified with a custom algorithm to detect multiple proteins. While cyc-DEP improved assay multiplicity, long runtimes threatened its clinical adoption. Here, we modify the original cyc-DEP platform to reduce assay runtimes. Nanoparticles were formulated from human prostate adenocarcinoma cells and collected using dielectrophoresis. Three proteins were labeled on-chip with a mixture of short oligonucleotide-conjugated antibodies. The sample was then incubated with complementary fluorophore-conjugated oligonucleotides, which were dehybridized using an ethylene carbonate buffer after each round of imaging. Oligonucleotide removal exhibited an average quenching efficiency of 98 ± 3% (n = 12 quenching events), matching the original cyc-DEP platform. The presented "oligo cyc-DEP" platform achieved clinically relevant sample-to-answer times, reducing the duration for three rounds of cyclic immunolabeling from approximately 20 to 6.5 h-a 67% decrease attributed to rapid fluorophore removal and the consolidated co-incubation of antibodies.

Collection of serum albumin aggregate nanoparticles from human plasma by dielectrophoresis

Dielectrophoresis (DEP) is a fast and reliable nanoparticle recovery method that utilizes nonuniform electric fields to manipulate particles based on their material composition and size, enabling recovery of biologically-derived nanoparticles from plasma for diagnostic applications. When applying DEP to undiluted human plasma, collection of endogenous albumin proteins was observed at electric field gradients much lower than predicted by theory to collect molecular proteins. To understand this collection, nanoparticle tracking analysis of bovine serum albumin (BSA) dissolved in 0.5× phosphate-buffered saline was performed and showed that albumin spontaneously formed aggregate nanoparticles with a mean diameter of 237 nm. These aggregates experienced a dielectrophoretic force as a function of aggregate radius rather than the diameter of individual protein molecules which contributed to their collection. In high conductance buffer (6.8 mS/cm), DEP was able to move these aggregates into regions of high electric field gradient, and in lower conductance buffer (0.68 mS/cm), these aggregates could be moved into high or low gradient regions depending on the applied frequency. Disruption of BSA aggregates using a nonionic detergent significantly decreased the particle diameter, resulting in decreased dielectrophoretic collection of albumin which increased the collection consistency of particles of interest. These results provide techniques to manipulate albumin aggregates via DEP, which impacts collection of diagnostic biomarkers.

Recent Advances in Image-Guided Tissue Sampling

Recent advances in image-guided tissue sampling have enhanced diagnostic medicine, particularly in oncology. Traditional techniques, such as computed tomography (CT)-, ultrasound (US)-, and magnetic resonance imaging (MRI)-guided biopsies, remain the cornerstone of diagnostic interventions, each offering unique advantages based on tissue characteristics. CT-guided biopsies excel in deeper complex lesions, while US-guided biopsies provide real-time imaging ideal for superficial tissues. MRI-guided biopsies are invaluable for soft tissue evaluations. The emergence of fusion imaging, which combines modalities such as positron emission tomography (PET)/CT or MRI/US, has demonstrated enhanced diagnostic accuracy. Despite these advantages, image co-registration and cost are the main drawbacks. Emerging techniques such as molecular breast imaging (MBI) and shear wave elastography (SWE) have been evaluated, particularly for breast cancer; however, research suggests that US is likely to remain the most effective modality due to both its cost and ease of use. Innovations in biopsy navigation, including augmented reality, "hot needles," and robotic assistance, demonstrate promise in closing the gap between operator dependency and procedural consistency; however, further research is required. While liquid biopsies show promise in non-invasive early cancer detection, they are not yet ready to replace tissue biopsies. Collectively, these advancements indicate a future where image-guided tissue sampling is more targeted, less invasive, and diagnostically accurate, although cost and technology access remain challenges.

Deciphering extracellular vesicles protein cargo in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) presents a significant therapeutic challenge as it is frequently diagnosed at advanced inoperable stages. Therefore, the development of a reliable screening tool for PDAC is crucial for effective prevention and treatment. Extracellular vesicles (EVs), characterized by their cup-shaped lipid bilayer structure and ubiquitous release from various cell types, offer notable advantages as an emerging liquid biopsy technique that is rapid, minimally invasive, easily sampled, and cost-effective. While EVs play a substantial role in cancer progression, EV proteins serve as direct mediators of diverse cellular behaviors and have immense potential as biomarkers for PDAC diagnosis and prognostication. This review provides an overview of EV proteins regarding PDAC diagnosis and prognostic implications as well as disease progression.

Biomechanics of circulating cellular and subcellular bioparticles: beyond separation

Biomechanical attributes have emerged as novel markers, providing a reliable means to characterize cellular and subcellular fractions. Numerous studies have identified correlations between these factors and patients' medical status. However, the absence of a thorough overview impedes their applicability in contemporary state-of-the-art therapeutic strategies. In this context, we provide a comprehensive analysis of the dimensions, configuration, rigidity, density, and electrical characteristics of normal and abnormal circulating cells. Subsequently, the discussion broadens to encompass subcellular bioparticles, such as extracellular vesicles (EVs) enriched either from blood cells or other tissues. Notably, cell sizes vary significantly, from 2 μm for platelets to 25 μm for circulating tumor cells (CTCs), enabling the development of size-based separation techniques, such as microfiltration, for specific diagnostic and therapeutic applications. Although cellular density is relatively constant among different circulating bioparticles, it allows for reliable density gradient centrifugation to isolate cells without altering their native state. Additionally, variations in EV surface charges (-6.3 to -45 mV) offer opportunities for electrophoretic and electrostatic separation methods. The distinctive mechanical properties of abnormal cells, compared to their normal counterparts, present an exceptional opportunity for diverse medical and biotechnological approaches. This review also aims to provide a holistic view of the current understanding of popular techniques in this domain that transcend conventional boundaries, focusing on early harvesting of malignant cells from body fluids, designing effective therapeutic options, cell targeting, and resonating with tissue and genetic engineering principles.

Development of liquid biopsy in detection and screening of pancreatic cancer

Pancreatic cancer is a highly lethal malignant tumor, which has the characteristics of occult onset, low early diagnosis rate, rapid development and poor prognosis. The reason for the high mortality is partly that pancreatic cancer is usually found in the late stage and missed the best opportunity for surgical resection. As a promising detection technology, liquid biopsy has the advantages of non-invasive, real-time and repeatable. In recent years, the continuous development of liquid biopsy has provided a new way for the detection and screening of pancreatic cancer. The update of biomarkers and detection tools has promoted the development of liquid biopsy. Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), circulating tumor RNA (ctRNA) and extracellular vesicles (EVs) provide many biomarkers for liquid biopsy of pancreatic cancer, and screening tools around them have also been developed. This review aims to report the application of liquid biopsy technology in the detection of pancreatic cancer patients, mainly introduces the biomarkers and some newly developed tools and platforms. We have also considered whether liquid biopsy technology can replace traditional tissue biopsy and the challenges it faces.

Weak Value Amplification-Based Biochip for Highly Sensitive Detection and Identification of Breast Cancer Exosomes

Exosomes constitute an emerging biomarker for cancer diagnosis because they carry multiple proteins that reflect the origins of the parent cell. The highly sensitive detection of exosomes is a crucial prerequisite for the diagnosis of cancer. In this study, we report an exosome detection system based on quantum weak value amplification (WVA). The WVA detection system consists of a reflection detection light path and a Zr-ionized biochip. Zr-ionized biochips effectively capture exosomes through the specific interaction between zirconium dioxide and the phosphate groups on the lipid bilayer of exosomes. Aptamer-modified gold nanoparticles (Au NPs) are then used to specifically recognize proteins on exosomes to enhance the detection signal. The sensitivity and resolution of the detection system are 2944.07 nm/RIU and 1.22 × 10-5 RIU, respectively. The concentration of exosomes can be directly quantified by the WVA system, ranging from 105-107 particles/mL with the detection limit of 3 × 104 particles/mL. The use of Au NPs-EpCAM for the specific enhancement of breast cancer MDA-MB-231 exosomes is demonstrated. The results indicate that the WVA detection system can be a promising candidate for the detection of exosomes as tumor markers.

A Current Synopsis of the Emerging Role of Extracellular Vesicles and Micro-RNAs in Pancreatic Cancer: A Forward-Looking Plan for Diagnosis and Treatment

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies worldwide, while it persists as the fourth most prevalent cause of cancer-related death in the United States of America. Although there are several novel therapeutic strategies for the approach of this intensely aggressive tumor, it remains a clinical challenge, as it is hard to identify in early stages, due to its asymptomatic course. A diagnosis is usually established when the disease is already in its late stages, while its chemoresistance constitutes an obstacle to the optimal management of this malignancy. The discovery of novel diagnostic and therapeutic tools is considered a necessity for this tumor, due to its low survival rates and treatment failures. One of the most extensively investigated potential diagnostic and therapeutic modalities is extracellular vesicles (EVs). These vesicles constitute nanosized double-lipid membraned particles that are characterized by a high heterogeneity that emerges from their distinct biogenesis route, their multi-variable sizes, and the particular cargoes that are embedded into these particles. Their pivotal role in cell-to-cell communication via their cargo and their implication in the pathophysiology of several diseases, including pancreatic cancer, opens new horizons in the management of this malignancy. Meanwhile, the interplay between pancreatic carcinogenesis and short non-coding RNA molecules (micro-RNAs or miRs) is in the spotlight of current studies, as they can have either a role as tumor suppressors or promoters. The deregulation of both of the aforementioned molecules leads to several aberrations in the function of pancreatic cells, leading to carcinogenesis. In this review, we will explore the role of extracellular vesicles and miRNAs in pancreatic cancer, as well as their potent utilization as diagnostic and therapeutic tools.

Single extracellular vesicle surface protein-based blood assay identifies potential biomarkers for detection and screening of five cancers

Extracellular vesicles (EVs) and EV proteins are promising biomarkers for cancer liquid biopsy. Herein, we designed a case-control study involving 100 controls and 100 patients with esophageal, stomach, colorectal, liver, or lung cancer to identify common and type-specific biomarkers of plasma-derived EV surface proteins for the five cancers. EV surface proteins were profiled using a sequencing-based proximity barcoding assay. In this study, five differentially expressed proteins (DEPs) and eight differentially expressed protein combinations (DEPCs) showed promising performance (area under curve, AUC > 0.900) in pan-cancer identification [e.g., TENM2 (AUC = 0.982), CD36 (AUC = 0.974), and CD36-ITGA1 (AUC = 0.971)]. Our classification model could properly discriminate between cancer patients and controls using DEPs (AUC = 0.981) or DEPCs (AUC = 0.965). When distinguishing one cancer from the other four, the accuracy of the classification model using DEPCs (85-92%) was higher than that using DEPs (78-84%). We validated the performance in an additional 14 cancer patients and 14 controls, and achieved an AUC value of 0.786 for DEPs and 0.622 for DEPCs, highlighting the necessity to recruit a larger cohort for further validation. When clustering EVs into subpopulations, we detected cluster-specific proteins highly expressed in immune-related tissues. In the context of colorectal cancer, we identified heterogeneous EV clusters enriched in cancer patients, correlating with tumor initiation and progression. These findings provide epidemiological and molecular evidence for the clinical application of EV proteins in cancer prediction, while also illuminating their functional roles in cancer physiopathology.

An Alternating Current Electroosmotic Flow-Based Ultrasensitive Electrochemiluminescence Microfluidic System for Ultrafast Monitoring, Detection of Proteins/miRNAs in Unprocessed Samples

Early diagnosis of acute diseases is restricted by the sensitivity and complex process of sample treatment. Here, an ultrasensitive, rapid, and portable electrochemiluminescence-microfluidic (ECL-M) system is described via sandwich-type immunoassay and surface plasmonic resonance (SPR) assay. Using a sandwich immunoreaction approach, the ECL-M system employs cardiac troponin-I antigen (cTnI) as a detection model with a Ru@SiO2 NPs labeled antibody as the signal probe. For miR-499-5p detection, gold nanoparticles generate SPR effects to enhance Ru(bpy)3 2+ ECL signals. The system based on alternating current (AC) electroosmotic flow achieves an LOD of 2 fg mL-1 for cTnI in 5 min and 10 aM for miRNAs in 10 min at room temperature. The point-of-care testing (POCT) device demonstrated 100% sensitivity and 98% specificity for cTnI detection in 123 clinical serum samples. For miR-499-5p, it exhibited 100% sensitivity and 97% specificity in 55 clinical serum samples. Continuous monitoring of these biomarkers in rats' saliva, urine, and interstitial fluid samples for 48 hours revealed observations rarely documented in biotic fluids. The ECL-M POCT device stands as a top-performing system for ECL analysis, offering immense potential for ultrasensitive, rapid, highly accurate, and facile detection and monitoring of acute diseases in POC settings.

Clinical Application of Liquid Biopsy in Pancreatic Cancer: A Narrative Review

Pancreatic ductal adenocarcinoma contributes significantly to global cancer-related deaths, featuring only a 10% survival rate over five years. The quest for novel tumor markers is critical to facilitate early diagnosis and tailor treatment strategies for this disease, which is key to improving patient outcomes. In pancreatic ductal adenocarcinoma, these markers have been demonstrated to play a crucial role in early identification, continuous monitoring, and prediction of its prognosis and have led to better patient outcomes. Nowadays, biopsy specimens serve to ascertain diagnosis and determine tumor type. However, liquid biopsies present distinct advantages over conventional biopsy techniques. They offer a noninvasive, easily administered procedure, delivering insights into the tumor's status and facilitating real-time monitoring. Liquid biopsies encompass a variety of elements, such as circulating tumor cells, circulating tumor DNA, extracellular vesicles, microRNAs, circulating RNA, tumor platelets, and tumor endothelial cells. This review aims to provide an overview of the clinical applications of liquid biopsy as a technique in the management of pancreatic cancer.

A Comprehensive Review of the Potential Role of Liquid Biopsy as a Diagnostic, Prognostic, and Predictive Biomarker in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma is one of the most lethal malignant diseases, with a mortality rate being close to incidence. Due to its heterogeneity and plasticity, as well as the lack of distinct symptoms in the early phases, it is very often diagnosed at an advanced stage, resulting in poor prognosis. Traditional tissue biopsies remain the gold standard for making a diagnosis, but have an obvious disadvantage in their inapplicability for frequent sampling. Blood-based biopsies represent a non-invasive method which potentially offers easy and repeated sampling, leading to the early detection and real-time monitoring of the disease and hopefully an accurate prognosis. Given the urgent need for a reliable biomarker that can estimate a patient's condition and response to an assigned treatment, blood-based biopsies are emerging as a potential new tool for improving patients' survival and surveillance. In this article, we discuss the current advances and challenges in using liquid biopsies for pancreatic cancer, focusing on circulating tumour DNA (ctDNA), extracellular vesicles (EVs), and circulating tumour cells (CTCs), and compare the performance and reliability of different biomarkers and combinations of biomarkers.

Prostate cancer-derived small extracellular vesicle proteins: the hope in diagnosis, prognosis, and therapeutics

Current diagnostic tools for prostate cancer (PCa) diagnosis and risk stratification are insufficient. The hidden onset and poor efficacy of traditional therapies against metastatic PCa make this disease a heavy burden in global men's health. Prostate cancer-derived extracellular vesicles (PCDEVs) have garnered attention in recent years due to their important role in communications in tumor microenvironment. Recent advancements have demonstrated PCDEVs proteins play an important role in PCa invasion, progression, metastasis, therapeutic resistance, and immune escape. In this review, we briefly discuss the applications of sEV proteins in PCa diagnosis and prognosis in liquid biopsy, focus on the roles of the PCa-derived small EVs (sEVs) proteins in tumor microenvironment associated with cancer progression, and explore the therapeutic potential of sEV proteins applied for future metastatic PCa therapy.

Thinking small to win big? A critical review on the potential application of extracellular vesicles for biomarker discovery and new therapeutic approaches in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extremely deadly form of cancer, with limited progress in 5-year survival rates despite significant research efforts. The main challenges in treating PDAC include difficulties in early detection, and resistance to current therapeutic approaches due to aggressive molecular and microenvironment features. These challenges emphasize the importance of identifying clinically validated biomarkers for early detection and clinical management. Extracellular vesicles (EVs), particularly exosomes, have emerged as crucial mediators of intercellular communication by transporting molecular cargo. Recent research has unveiled their role in initiation, metastasis, and chemoresistance of PDAC. Consequently, utilizing EVs in liquid biopsies holds promise for the identification of biomarkers for early detection, prognosis, and monitoring of drug efficacy. However, numerous limitations, including challenges in isolation and characterization of homogeneous EVs populations, as well as the absence of standardized protocols, can affect the reliability of studies involving EVs as biomarkers, underscoring the necessity for a prudent approach. EVs have also garnered considerable attention as a promising drug delivery system and novel therapy for tumors. The loading of biomolecules or chemical drugs into exosomes and their subsequent delivery to target cells can effectively impede tumor progression. Nevertheless, there are obstacles that must be overcome to ensure the accuracy and efficacy of therapies relying on EVs for the treatment of tumors. In this review, we examine both recent advancements and remaining obstacles, exploring the potential of utilizing EVs in biomarker discovery as well as for the development of drug delivery vehicles.

Microfluidic-based technologies in cancer liquid biopsy: Unveiling the role of horizontal gene transfer (HGT) materials

Liquid biopsy includes the isolating and analysis of non-solid biological samples enables us to find new ways for molecular profiling, prognostic assessment, and better therapeutic decision-making in cancer patients. Despite the conventional theory of tumor development, a non-vertical transmission of DNA has been reported among cancer cells and between cancer and normal cells. The phenomenon referred to as horizontal gene transfer (HGT) has the ability to amplify the advancement of tumors by disseminating genes that encode molecules conferring benefits to the survival or metastasis of cancer cells. Currently, common liquid biopsy approaches include the analysis of extracellular vesicles (EVs) and tumor-free DNA (tfDNA) derived from primary tumors and their metastatic sites, which are well-known HGT mediators in cancer cells. Current technological and molecular advances expedited the high-throughput and high-sensitive HGT materials analyses by using new technologies, such as microfluidics in liquid biopsies. This review delves into the convergence of microfluidic-based technologies and the investigation of Horizontal Gene Transfer (HGT) materials in cancer liquid biopsy. The integration of microfluidics offers unprecedented advantages such as high sensitivity, rapid analysis, and the ability to analyze rare cell populations. These attributes are instrumental in detecting and characterizing CTCs, circulating nucleic acids, and EVs, which are carriers of genetic cargo that could potentially undergo HGT. The phenomenon of HGT in cancer has raised intriguing questions about its role in driving genomic diversity and acquired drug resistance. By leveraging microfluidic platforms, researchers have been able to capture and analyze individual cells or genetic material with enhanced precision, shedding light on the potential transfer of genetic material between cancer cells and surrounding stromal cells. Furthermore, the application of microfluidics in single-cell sequencing has enabled the elucidation of the genetic changes associated with HGT events, providing insights into the evolution of tumor genomes. This review also discusses the challenges and opportunities in studying HGT materials using microfluidic-based technologies. In conclusion, microfluidic-based technologies have significantly advanced the field of cancer liquid biopsy, enabling the sensitive and accurate detection of HGT materials. As the understanding of HGT's role in tumor evolution and therapy resistance continues to evolve, the synergistic integration of microfluidics and HGT research promises to provide valuable insights into cancer biology, with potential implications for precision oncology and therapeutic strategies.

Continuous-flow electrorotation (cROT): improved throughput characterization for dielectric properties of cancer cells

This paper presents the concept of a newly developed high-throughput measurement device for determining the dielectric properties of cancer cells. The proposed continuous-flow electrorotation (cROT) device can induce electrorotation (ROT) with vertical rotation using two sets of interdigitated electrodes on the top and bottom substrates to torque the cells. In the developed device, multiple rotating cells flowing in a microchannel are aligned between electrodes using dielectrophoresis. This allows for the measurement of the rotational behavior of the cells with continuous flow, resulting in a significant improvement in throughput compared to the conventional ROT devices reported previously. The dielectric properties, permittivity of the cell membrane and conductivity of the cell cytoplasm, of HeLa cells obtained by simultaneous measurements using the developed cROT device were 9.13 ± 1.02 and 0.93 ± 0.10 S m-1, respectively. Moreover, the measurement throughput was successfully increased to 2700 cells per h using the cROT technique.

Identification of exosome protein panels as predictive biomarkers for non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) remains a leading cause of cancer-related deaths worldwide, primarily due to its propensity for metastasis. Patients diagnosed with localized primary cancer have higher survival rates than those with metastasis. Thus, it is imperative to discover biomarkers for the early detection of NSCLC and the timely prediction of tumor metastasis to improve patient outcomes.

METHODS

Here, we utilized an integrated approach to isolate and characterize plasma exosomes from NSCLC patients as well as healthy individuals. We then conducted proteomics analysis and parallel reaction monitoring to identify and validate the top-ranked proteins of plasma exosomes.

RESULTS

Our study revealed that the proteome in exosomes from NSCLC patients with metastasis was distinctly different from that from healthy individuals. The former had larger diameters and lower concentrations of exosomes than the latter. Furthermore, among the 1220 identified exosomal proteins, we identified two distinct panels of biomarkers. The first panel of biomarkers (FGB, FGG, and VWF) showed potential for early NSCLC diagnosis and demonstrated a direct correlation with the survival duration of NSCLC patients. The second panel of biomarkers (CFHR5, C9, and MBL2) emerged as potential biomarkers for assessing NSCLC metastasis, of which CFHR5 alone was significantly associated with the overall survival of NSCLC patients.

CONCLUSIONS

These findings underscore the potential of plasma exosomal biomarkers for early NSCLC diagnosis and metastasis prediction. Notably, CFHR5 stands out as a promising prognostic indicator for NSCLC patients. The clinical utility of exosomal biomarkers offers the potential to enhance the management of NSCLC.

Hydrogel-Loaded Exosomes: A Promising Therapeutic Strategy for Musculoskeletal Disorders

Clinical treatment strategies for musculoskeletal disorders have been a hot research topic. Accumulating evidence suggests that hydrogels loaded with MSC-derived EVs show great potential in improving musculoskeletal injuries. The ideal hydrogels should be capable of promoting the development of new tissues and simulating the characteristics of target tissues, with the properties matching the cell-matrix constituents of autologous tissues. Although there have been numerous reports of hydrogels loaded with MSC-derived EVs for the repair of musculoskeletal injuries, such as intervertebral disc injury, tendinopathy, bone fractures, and cartilage injuries, there are still many hurdles to overcome before the clinical application of modified hydrogels. In this review, we focus on the advantages of the isolation technique of EVs in combination with different types of hydrogels. In this context, the efficacy of hydrogels loaded with MSC-derived EVs in different musculoskeletal injuries is discussed in detail to provide a reference for the future application of hydrogels loaded with MSC-derived EVs in the clinical treatment of musculoskeletal injuries.

Ultrafast and Controlled Capturing, Loading, and Release of Extracellular Vesicles by a Portable Microstructured Electrochemical Fluidic Device

Extracellular vesicles (EVs) are secreted by all living cells and are found in body fluids. They exert numerous physiological and pathological functions and serve as cargo shuttles. Due to their safety and inherent bioactivity, they have emerged as versatile therapeutic agents, biomarkers, and potential drug carriers. Despite the growing interest in EVs, current progress in this field is, in part, limited by relatively inefficient isolation techniques. Conventional methods are indeed slow, laborious, require specialized laboratory equipment, and may result in low yield and purity. This work describes an electrochemically controlled "all-in-one" device enabling capturing, loading, and releasing of EVs. The device is composed of a fluidic channel confined within antibody-coated microstructured electrodes. It rapidly isolates EVs with a high level of purity from various biofluids. As a proof of principle, the device is applied to isolate EVs from skin wounds of healthy and diabetic mice. Strikingly, it is found that EVs from healing wounds of diabetic mice are enriched in mitochondrial proteins compared to those of healthy mice. Additionally, the device improves the loading protocol of EVs with polyplexes, and may therefore find applications in nucleic acid delivery. Overall, the electrochemical device can greatly facilitate the development of EVs-based technologies.

Rapid purification and multiparametric characterization of circulating small extracellular vesicles utilizing a label-free lab-on-a-chip device

Nano-scale extracellular vesicles are lipid-bilayer delimited particles that are naturally secreted by all cells and have emerged as valuable biomarkers for a wide range of diseases. Efficient isolation of small extracellular vesicles while maintaining yield and purity is crucial to harvest their potential in diagnostic, prognostic, and therapeutic applications. Most conventional methods of isolation suffer from significant shortcomings, including low purity or yield, long duration, need for large sample volumes, specialized equipment, trained personnel, and high costs. To address some of these challenges, our group has reported a novel insulator-based dielectrophoretic device for rapid isolation of small extracellular vesicles from biofluids and cell culture media based on their size and dielectric properties. In this study, we report a comprehensive characterization of small extracellular vesicles isolated from cancer-patients' biofluids at a twofold enrichment using the device. The three-fold characterization that was performed using conventional flow cytometry, advanced imaging flow cytometry, and microRNA sequencing indicated high yield and purity of the isolated small extracellular vesicles. The device thus offers an efficient platform for rapid isolation while maintaining biomolecular integrity.

Development of a blood-based extracellular vesicle classifier for detection of early-stage pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has an overall 5-year survival rate of just 12.5% and thus is among the leading causes of cancer deaths. When detected at early stages, PDAC survival rates improve substantially. Testing high-risk patients can increase early-stage cancer detection; however, currently available liquid biopsy approaches lack high sensitivity and may not be easily accessible.

METHODS

Extracellular vesicles (EVs) were isolated from blood plasma that was collected from a training set of 650 patients (105 PDAC stages I and II, 545 controls). EV proteins were analyzed using a machine learning approach to determine which were the most informative to develop a classifier for early-stage PDAC. The classifier was tested on a validation cohort of 113 patients (30 PDAC stages I and II, 83 controls).

RESULTS

The training set demonstrates an AUC of 0.971 (95% CI = 0.953-0.986) with 93.3% sensitivity (95% CI: 86.9-96.7) at 91.0% specificity (95% CI: 88.3-93.1). The trained classifier is validated using an independent cohort (30 stage I and II cases, 83 controls) and achieves a sensitivity of 90.0% and a specificity of 92.8%.

CONCLUSIONS

Liquid biopsy using EVs may provide unique or complementary information that improves early PDAC and other cancer detection. EV protein determinations herein demonstrate that the AC Electrokinetics (ACE) method of EV enrichment provides early-stage detection of cancer distinct from normal or pancreatitis controls.

Liquid biopsy techniques and pancreatic cancer: diagnosis, monitoring, and evaluation

Pancreatic cancer (PC) is one of the most common malignancies. Surgical resection is a potential curative approach for PC, but most patients are unsuitable for operations when at the time of diagnosis. Even with surgery, some patients may still experience tumour metastasis during the operation or shortly after surgery, as precise prognosis evaluation is not always possible. If patients miss the opportunity for surgery and resort to chemotherapy, they may face the challenging issue of chemotherapy resistance. In recent years, liquid biopsy has shown promising prospects in disease diagnosis, treatment monitoring, and prognosis assessment. As a noninvasive detection method, liquid biopsy offers advantages over traditional diagnostic procedures, such as tissue biopsy, in terms of both cost-effectiveness and convenience. The information provided by liquid biopsy helps clinical practitioners understand the molecular mechanisms underlying tumour occurrence and development, enabling the formulation of more precise and personalized treatment decisions for each patient. This review introduces molecular biomarkers and detection methods in liquid biopsy for PC, including circulating tumour cells (CTCs), circulating tumour DNA (ctDNA), noncoding RNAs (ncRNAs), and extracellular vesicles (EVs) or exosomes. Additionally, we summarize the applications of liquid biopsy in the early diagnosis, treatment response, resistance assessment, and prognostic evaluation of PC.

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

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

A smart TESTER for reliable discrimination of cancer-derived small extracellular vesicles

Cancer-derived small extracellular vesicles (csEVs) are crucial liquid biopsy indicators that reflect the presence and progression of many malignancies. However, reliable discrimination of csEVs remains a great challenge owing to the interference from normal sEVs (nsEVs) and low abundance in the early stages of cancer. In this work, we developed a Two-Elements Selectively Triggered csEVs Recognization (TESTER) strategy for selective identification of csEVs from the complex clinical body fluid samples. This method was based on the MNAzyme-controlled synchronous recognition to EpCAM and CD63 proteins on the membrane of csEVs. Efficient recognition to csEVs via EpCAM aptamer and CD63 aptamer prompted the release of Partzyme A and Partzyme B probes to induce a MNAzyme structure formation, resulting in the cyclic cleavage of substrate chain to produce cascade fluorescence signal amplification. The detection threshold of the developed TESTER approach for csEVs in complicated biological samples was 72 particles μL-1, accomplishing the highly sensitive and selective quantification of csEVs. At the same time, we successfully constructed a new platform for bimolecular simultaneous recognition, which provides a good idea for the construction of bimolecular-activated detection switch in the future.

Engineered exosomes as drug and RNA co-delivery system: new hope for enhanced therapeutics?

Chemotherapy often faces some obstacles such as low targeting effects and drug resistance, which introduce the low therapeutic efficiency and strong side effects. Recent advances in nanotechnology allows the use of novel nanosystems for targeted drug delivery, although the chemically synthesized nanomaterials always show unexpected low biocompability. The emergence of exosome research has offered a better understanding of disease treatment and created novel opportunities for developing effective drug delivery systems with high biocompability. Moreover, RNA interference has emerged as a promising strategy for disease treatments by selectively knocking down or over-expressing specific genes, which allows new possibilities to directly control cell signaling events or drug resistance. Recently, more and more interests have been paid to develop optimal delivery nanosystems with high efficiency and high biocompability for drug and functional RNA co-delivery to achieve enhanced chemotherapy. In light of the challenges for developing drug and RNA co-delivery system, exosomes have been found to show very attractive prospects. This review aims to explore current technologies and challenges in the use of exosomes as drug and RNA co-delivery system with a focus on the emerging trends and issues associated with their further applications, which may contribute to the accelerated developments of exosome-based theraputics.

Engineered extracellular vesicles-like biomimetic nanoparticles as an emerging platform for targeted cancer therapy

Nanotechnology offers the possibility of revolutionizing cancer theranostics in the new era of precision oncology. Extracellular vesicles (EVs)-like biomimetic nanoparticles (EBPs) have recently emerged as a promising platform for targeted cancer drug delivery. Compared with conventional synthetic vehicles, EBPs have several advantages, such as lower immunogenicity, longer circulation time, and better targeting capability. Studies on EBPs as cancer therapeutics are rapidly progressing from in vitro experiments to in vivo animal models and early-stage clinical trials. Here, we describe engineering strategies to further improve EBPs as effective anticancer drug carriers, including genetic manipulation of original cells, fusion with synthetic nanomaterials, and direct modification of EVs. These engineering approaches can improve the anticancer performance of EBPs, especially in terms of tumor targeting effectiveness, stealth property, drug loading capacity, and integration with other therapeutic modalities. Finally, the current obstacles and future perspectives of engineered EBPs as the next-generation delivery platform for anticancer drugs are discussed.

Absolute Quantification of Serum Exosomes in Patients with an SERS-Lateral Flow Strip Biosensor for Noninvasive Clinical Cancer Diagnosis

Exosomes (exos) widely existing in body fluids show great potential for noninvasive cancer diagnosis. Quantitative analysis of exos is traditionally performed by targeting specific exosomal surface proteins, but it is often imprecise due to the common expression of exosomal proteins and subtle expression differences between different cancer subtypes. Herein, we report quantitative surface-enhanced Raman spectroscopy (SERS) of serum exos through a combination of a paper-based lateral flow strip (LFS) biosensor with multivariate spectral unmixing analysis rather than simply quantifying exosomal proteins. Our SERS-LFS biosensor enables absolute quantification of two different serum exos with a limit of detection down to ∼106 particles/mL for both exos. We further exemplify the application of this strategy in quantitative dual-plex detection of serum exos from breast cancer patients. We find that human epidermal growth factor receptor 2+ (HER2+) and luminal A breast cancer patients undergoing no surgery are enriched in serum exos derived from SKBR-3 cells and MCF-7 cells (denoted as SKBR and MCF exos), respectively. The surgical treatment of these breast cancer patients accompanies an obvious decrease of either SKBR or MCF exos in the serum. These results suggest the great potential of the combination of the SERS-LFS biosensor and multivariate spectral unmixing for breast cancer subtyping and therapeutic surveillance with the powerful quantitative capability of exos in clinical samples.

Graphene Sensor Arrays for Rapid and Accurate Detection of Pancreatic Cancer Exosomes in Patients' Blood Plasma Samples

Biosensors based on graphene field effect transistors (GFETs) have the potential to enable the development of point-of-care diagnostic tools for early stage disease detection. However, issues with reproducibility and manufacturing yields of graphene sensors, but also with Debye screening and unwanted detection of nonspecific species, have prevented the wider clinical use of graphene technology. Here, we demonstrate that our wafer-scalable GFETs array platform enables meaningful clinical results. As a case study of high clinical relevance, we demonstrate an accurate and robust portable GFET array biosensor platform for the detection of pancreatic ductal adenocarcinoma (PDAC) in patients' plasma through specific exosomes (GPC-1 expression) within 45 min. In order to facilitate reproducible detection in blood plasma, we optimized the analytical performance of GFET biosensors via the application of an internal control channel and the development of an optimized test protocol. Based on samples from 18 PDAC patients and 8 healthy controls, the GFET biosensor arrays could accurately discriminate between the two groups while being able to detect early cancer stages including stages 1 and 2. Furthermore, we confirmed the higher expression of GPC-1 and found that the concentration in PDAC plasma was on average more than 1 order of magnitude higher than in healthy samples. We found that these characteristics of GPC-1 cancerous exosomes are responsible for an increase in the number of target exosomes on the surface of graphene, leading to an improved signal response of the GFET biosensors. This GFET biosensor platform holds great promise for the development of an accurate tool for the rapid diagnosis of pancreatic cancer.

Enhancement of dielectrophoresis-based particle collection from high conducting fluids due to partial electrode insulation

Dielectrophoresis (DEP) is a successful method to recover nanoparticles from different types of fluid. The DEP force acting on these particles is created by an electrode microarray that produces a nonuniform electric field. To apply DEP to a highly conducting biological fluid, a protective hydrogel coating over the metal electrodes is required to create a barrier between the electrode and the fluid. This protects the electrodes, reduces the electrolysis of water, and allows the electric field to penetrate into the fluid sample. We observed that the protective hydrogel layer can separate from the electrode and form a closed domed structure and that collection of 100 nm polystyrene beads increased when this occurred. To better understand this collection increase, we used COMSOL Multiphysics software to model the electric field in the presence of the dome filled with different materials ranging from low-conducting gas to high conducting phosphate-buffered saline fluids. The results suggest that as the electrical conductivity of the material inside the dome is reduced, the whole dome acts as an insulator which increases electric field intensity at the electrode edge. This increased intensity widens the high-intensity electric field factor zone resulting in increased collection. This informs how dome formation results in increased particle collection and provides insight into how the electric field can be intensified to the increase collection of particles. These results have important applications for increasing the recovery of biologically-derived nanoparticles from undiluted physiological fluids that have high conductance, including the collection of cancer-derived extracellular vesicles from plasma for liquid biopsy applications.

Placental Exosomes as Biomarkers for Maternal Diseases: Current Advances in Isolation, Characterization, and Detection

Serving as the interface between fetal and maternal circulation, the placenta plays a critical role in fetal growth and development. Placental exosomes are small membrane-bound extracellular vesicles released by the placenta during pregnancy. They contain a variety of biomolecules, including lipids, proteins, and nucleic acids, which can potentially be biomarkers of maternal diseases. An increasing number of studies have demonstrated the utility of placental exosomes for the diagnosis and monitoring of pathological conditions such as pre-eclampsia and gestational diabetes. This suggests that placental exosomes may serve as new biomarkers in liquid biopsy analysis. This review provides an overview of the current understanding of the biological function of placental exosomes and their potential as biomarkers of maternal diseases. Additionally, this review highlights current barriers and the way forward for standardization and validation of known techniques for exosome isolation, characterization, and detection. Finally, microfluidic devices for exosome research are discussed.

A Review of Extracellular Vesicles in COVID-19 Diagnosis, Treatment, and Prevention

The 2019 novel coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is ongoing, and has necessitated scientific efforts in disease diagnosis, treatment, and prevention. Interestingly, extracellular vesicles (EVs) have been crucial in these developments. EVs are a collection of various nanovesicles which are delimited by a lipid bilayer. They are enriched in proteins, nucleic acids, lipids, and metabolites, and naturally released from different cells. Their natural material transport properties, inherent long-term recycling ability, excellent biocompatibility, editable targeting, and inheritance of parental cell properties make EVs one of the most promising next-generation drug delivery nanocarriers and active biologics. During the COVID-19 pandemic, many efforts have been made to exploit the payload of natural EVs for the treatment of COVID-19. Furthermore, strategies that use engineered EVs to manufacture vaccines and neutralization traps have produced excellent efficacy in animal experiments and clinical trials. Here, the recent literature on the application of EVs in COVID-19 diagnosis, treatment, damage repair, and prevention is reviewed. And the therapeutic value, application strategies, safety, and biotoxicity in the production and clinical applications of EV agents for COVID-19 treatment, as well as inspiration for using EVs to block and eliminate novel viruses are discussed.

Catalytic hairpin assembly-assisted dual-signal amplification platform for ultrasensitive detection of tumor markers and intelligent diagnosis of gastric cancer

Quantification of extracellular tumor markers has shown great promise for non-invasive cancer diagnosis. Combined detection of multiple tumor markers instead of a single one is valuable for accurate diagnosis. Here, we integrate CRISPR-Cas12a with DNA catalytic hairpin assembly (CHA) to doubly amplify the output signal for detecting microRNA-182 (miR-182), which is overexpressed by gastric cancer patients. Additionally, we develop a CHA system with self-replicating capacity (SRCHA) to realize dual-signal amplification for the detection of carcinoembryonic antigen (CEA), a broad-spectrum tumor marker. The proposed cascade amplification strategies enable ultrasensitive detection of miR-182 and CEA with low LODs of 0.063 fM and 4.8 pg mL^-1, respectively. Moreover, we design a ternary "AND" logic gate using different concentrations of miR-182 and CEA as inputs, which demonstrates intelligent diagnosis of gastric cancer staging with a high accuracy of 93.3% in a clinical cohort of 30 individuals. Overall, our study expands the application of CRISPR-Cas12a in biosensing and provides a new diagnostic strategy for non-invasive liquid biopsy of gastric cancer before resorting to a traumatic tissue biopsy.

Glypican1: a potential cancer biomarker for nanotargeted therapy

Glypicans (GPCs) are generally involved in cellular signaling, growth and proliferation. Previous studies reported their roles in cancer proliferation. GPC1 is a co-receptor for a variety of growth-related ligands, thereby stimulating the tumor microenvironment by promoting angiogenesis and epithelial-mesenchymal transition (EMT). This work reviews GPC1-biomarker-assisted drug discovery by the application of nanostructured materials, creating nanotheragnostics for targeted delivery and application in liquid biopsies. The review includes details of GPC1 as a potential biomarker in cancer progression as well as a potential candidate for nano-mediated drug discovery.

Parkinson's Disease: From Genetics and Epigenetics to Treatment, a miRNA-Based Strategy

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, characterized by an initial and progressive loss of dopaminergic neurons of the substantia nigra pars compacta via a potentially substantial contribution from protein aggregates, the Lewy bodies, mainly composed of α-Synuclein among other factors. Distinguishing symptoms of PD are bradykinesia, muscular rigidity, unstable posture and gait, hypokinetic movement disorder and resting tremor. Currently, there is no cure for PD, and palliative treatments, such as Levodopa administration, are directed to relieve the motor symptoms but induce severe side effects over time. Therefore, there is an urgency for discovering new drugs in order to design more effective therapeutic approaches. The evidence of epigenetic alterations, such as the dysregulation of different miRNAs that may stimulate many aspects of PD pathogenesis, opened a new scenario in the research for a successful treatment. Along this line, a promising strategy for PD treatment comes from the potential exploitation of modified exosomes, which can be loaded with bioactive molecules, such as therapeutic compounds and RNAs, and can allow their delivery to the appropriate location in the brain, overcoming the blood-brain barrier. In this regard, the transfer of miRNAs within Mesenchymal stem cell (MSC)-derived exosomes has yet to demonstrate successful results both in vitro and in vivo. This review, besides providing a systematic overview of both the genetic and epigenetic basis of the disease, aims to explore the exosomes/miRNAs network and its clinical potential for PD treatment.

Continuous-flow label-free size fractionation of extracellular vesicles through electrothermal fluid rolls and dielectrophoresis synergistically integrated in a microfluidic device

Extracellular vesicles (EVs) are cell-derived bioparticles that play significant roles in various biological processes including cell-to-cell communication and intercellular delivery. Additionally, they hold great potential as liquid biopsy biomarkers for pre-diagnostic applications. However, the isolation of EV subpopulations, especially exosomes from a biological fluid remains a challenge due to their submicron range. Here, we demonstrate continuous-flow label-free size fractionation of EVs for the first time through a synergistic combination of electrothermal fluid rolls and dielectrophoresis in a microfluidic device. The device features three dimensional microelectrodes with unique sidewall contours that give rise to effective electrothermal fluid rolls in cooperation with dielectrophoretic forces for the electrokinetic manipulation and size separation of submicron particles. We first validate the device functionality by separating submicron polystyrene particles from binary mixtures with a cut-off size of ∼200 nm and then isolate intact exosomes from cell culture medium or blood serum with a high recovery rate and purity (∼80%). The device operation in a high-conductivity medium renders the method ideal for the purification of target bioparticles directly from physiological fluids, and may offer a robust and versatile platform for EV related diagnostic applications.

Exosomal miRNAs in the microenvironment of pancreatic cancer

Pancreatic cancer (PC) is highly aggressive having an extremely poor prognosis. The tumor microenvironment (TME) of PC is complex and heterogeneous. Various cellular components in the microenvironment are capable of secreting different active substances that are involved in promoting tumor development. Their release may occur via exosomes, the most abundant extracellular vesicles (EVs), that can carry numerous factors as well as act as a mean of intercellular communication. Emerging evidence suggests that miRNAs are involved in the regulation and control of many pathological and physiological processes. They can also be transported by exosomes from donor cells to recipient cells, thereby regulating the TME. Exosomal miRNAs show promise for use as future targets for PC diagnosis and prognosis, which may reveal new treatment strategies for PC. In this paper, we review the important role of exosomal miRNAs in mediating cellular communication in the TME of PC as well as their potential use in clinical applications.

The Role of Exosomes in Pancreatic Ductal Adenocarcinoma Progression and Their Potential as Biomarkers

Pancreatic ductal adenocarcinoma (PDAC), the most common pancreatic malignancy, is an aggressive and lethal cancer with a dismal five-year survival rate. Despite remarkable improvements in cancer therapeutics, the clinical outcome of PDAC patients remains poor due to late diagnosis of the disease. This highlights the importance of early detection, wherein biomarker evaluation including exosomes would be helpful. Exosomes, small extracellular vesicles (sEVs), are cell-secreted entities with diameters ranging from 50 to 150 nm that deliver cellular contents (e.g., proteins, lipids, and nucleic acids) from parent cells to regulate the cellular processes of targeted cells. Recently, an increasing number of studies have reported that exosomes serve as messengers to facilitate stromal-immune crosstalk within the PDAC tumor microenvironment (TME), and their contents are indicative of disease progression. Moreover, evidence suggests that exosomes with specific surface markers are capable of distinguishing patients with PDAC from healthy individuals. Detectable exosomes in bodily fluids (e.g., blood, urine, saliva, and pancreatic juice) are omnipresent and may serve as promising biomarkers for improving early detection and evaluating patient prognosis. In this review, we shed light on the involvement of exosomes and their cargos in processes related to disease progression, including chemoresistance, angiogenesis, invasion, metastasis, and immunomodulation, and their potential as prognostic markers. Furthermore, we highlight feasible clinical applications and the limitations of exosomes in liquid biopsies as tools for early diagnosis as well as disease monitoring. Taking advantage of exosomes to improve diagnostic capacity may provide hope for PDAC patients, although further investigation is urgently needed.

Liquid Biopsies, Novel Approaches and Future Directions

Cancer is among the leading causes of death worldwide. Early diagnosis and prognosis are vital to improve patients' outcomes. The gold standard of tumor characterization leading to tumor diagnosis and prognosis is tissue biopsy. Amongst the constraints of tissue biopsy collection is the sampling frequency and the incomplete representation of the entire tumor bulk. Liquid biopsy approaches, including the analysis of circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), circulating miRNAs, and tumor-derived extracellular vesicles (EVs), as well as certain protein signatures that are released in the circulation from primary tumors and their metastatic sites, present a promising and more potent candidate for patient diagnosis and follow up monitoring. The minimally invasive nature of liquid biopsies, allowing frequent collection, can be used in the monitoring of therapy response in real time, allowing the development of novel approaches in the therapeutic management of cancer patients. In this review we will describe recent advances in the field of liquid biopsy markers focusing on their advantages and disadvantages.

The next "sweet" spot for pancreatic ductal adenocarcinoma: Glycoprotein for early detection

Pancreatic ductal adenocarcinoma (PDAC) is the most common neoplastic disease of the pancreas, accounting for more than 90% of all pancreatic malignancies. As a highly lethal malignancy, PDAC is the fourth leading cause of cancer-related deaths worldwide with a 5-year overall survival of less than 8%. The efficacy and outcome of PDAC treatment largely depend on the stage of disease at the time of diagnosis. Surgical resection followed by adjuvant chemotherapy remains the only possibly curative therapy, yet 80%-90% of PDAC patients present with nonresectable PDAC stages at the time of clinical presentation. Despite our advancing knowledge of PDAC, the prognosis remains strikingly poor, which is primarily due to the difficulty of diagnosing PDAC at the early stages. Recent advances in glycoproteomics and glycomics based on mass spectrometry have shown that aberrations in protein glycosylation plays a critical role in carcinogenesis, tumor progression, metastasis, chemoresistance, and immuno-response of PDAC and other types of cancers. A growing interest has thus been placed upon protein glycosylation as a potential early detection biomarker for PDAC. We herein take stock of the advancements in the early detection of PDAC that were carried out with mass spectrometry, with special focus on protein glycosylation.

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.