Microfluidic device for one-step detection of breast cancer-derived exosomal mRNA in blood using signal-amplifiable 3D nanostructure

Deep learning-assisted monitoring of trastuzumab efficacy in HER2-Overexpressing breast cancer via SERS immunoassays of tumor-derived urinary exosomal biomarkers

Monitoring drug efficacy is significant in the current concept of companion diagnostics in metastatic breast cancer. Trastuzumab, a drug targeting human epidermal growth factor receptor 2 (HER2), is an effective treatment for metastatic breast cancer. However, some patients develop resistance to this therapy; therefore, monitoring its efficacy is essential. Here, we describe a deep learning-assisted monitoring of trastuzumab efficacy based on a surface-enhanced Raman spectroscopy (SERS) immunoassay against HER2-overexpressing mouse urinary exosomes. Individual Raman reporters bearing the desired SERS tag and exosome capture substrate were prepared for the SERS immunoassay; SERS tag signals were collected to prepare deep learning training data. Using this deep learning algorithm, various complicated mixtures of SERS tags were successfully quantified and classified. Exosomal antigen levels of five types of cell-derived exosomes were determined using SERS-deep learning analysis and compared with those obtained via quantitative reverse transcription polymerase chain reaction and western blot analysis. Finally, drug efficacy was monitored via SERS-deep learning analysis using urinary exosomes from trastuzumab-treated mice. Use of this monitoring system should allow proactive responses to any treatment-resistant issues.

Nanoarchitectonics-based electrochemical aptasensors for highly efficient exosome detection

Exosomes, a type of extracellular vesicles, have attracted considerable attention due to their ability to provide valuable insights into the pathophysiological microenvironment of the cells from which they originate. This characteristic implicates their potential use as diagnostic disease biomarkers clinically, including cancer, infectious diseases, neurodegenerative disorders, and cardiovascular diseases. Aptasensors, which are electrochemical aptamers based biosensing devices, have emerged as a new class of powerful detection technology to conventional methods like ELISA and Western analysis, primarily because of their capability for high-performance bioanalysis. This review covers the current research landscape on the detection of exosomes utilizing nanoarchitectonics strategy for the development of electrochemical aptasensors. Strategies involving signal amplification and biofouling prevention are discussed, with an emphasis on nanoarchitectonics-based bio-interfaces, showcasing their potential to enhance sensitivity and selectivity through optimal conduction and mass transport properties. The ongoing challenges to broaden the clinical applications of these biosensors are also highlighted.

Liposome-integrated hydrogel hybrids: Promising platforms for cancer therapy and tissue regeneration

Drug delivery platforms have gracefully emerged as an indispensable component of novel cancer chemotherapy, bestowing targeted drug distribution, elevating therapeutic effects, and reducing the burden of unwanted side effects. In this context, hybrid delivery systems artfully harnessing the virtues of liposomes and hydrogels bring remarkable benefits, especially for localized cancer therapy, including intensified stability, excellent amenability to hydrophobic and hydrophilic medications, controlled liberation behavior, and appropriate mucoadhesion to mucopenetration shift. Moreover, three-dimensional biocompatible liposome-integrated hydrogel networks have attracted unprecedented interest in tissue regeneration, given their tunable architecture and physicochemical properties, as well as enhanced mechanical support. This review elucidates and presents cutting-edge developments in recruiting liposome-integrated hydrogel systems for cancer treatment and tissue regeneration.

All-in-one detection of breast cancer-derived exosomal miRNA on a pen-based paper chip

Exosomal microRNAs (miRNAs) play a pivotal role in intercellular communication, regulating gene expression in target cells, and hold significant promise as cancer biomarkers for early detection and screening. However, achieving precise and viable detection of exosomal miRNAs remains a challenge. This paper proposes an all-in-one detection strategy for breast cancer-derived exosomal miRNA-21 on a pen-based paper chip (PPC). The PPC is constructed using a modified automatic pen and lateral flow assay (LFA), which results in a cost-effective fabrication process. The user only needs to add the sample and trigger the top of the self-contained PPC after a period of time to complete the entire detection process. To enhance the sensitivity of exosomal miRNA testing, an enzyme-free catalyzed hairpin assembly (CHA) is further introduced, enabling highly sensitive detection of miRNA-21 with a limit of detection (LOD) of 25 fmol. Additionally, the detection of miRNAs in differentially-expressed cells and clinical samples has also been successfully achieved with high specificity. Overall, the proposed PPC provides an effective tool for detecting early cancer, monitoring diseases, and establishing point of care testing (POCT).

Exosomal miRNAs from neutrophils act as accurate biomarkers for gastric cancer diagnosis

BACKGROUND

Gastric cancer (GC) is the third leading cause of cancer-related death worldwide. Sensitive and accurate biomarkers can greatly aid in early diagnosis and favorable prognosis. Neutrophils are the most abundant immune cells in human circulation and play a critical role in tumor progression. Neutrophil-derived exosomes (Neu-Exo) contain abundant bioactive molecules and are critically involved in disease progression.

METHODS

We proposed a Dynabeads-based (CD66b antibody-coupled) separation and detection system for Neu-Exo analysis. Dual antibody-assisted fluorescent Dynabeads was established to detect Neu-Exo abundance. MiRNA signature of Neu-Exo was identified by RNA sequencing. QRT-PCR and droplet digital PCR (ddPCR) were used for candidate miRNA detection and the potential of Neu-Exo miRNAs in the diagnosis of gastric cancer was evaluated.

RESULTS

Dual antibody-assisted fluorescent Dynabeads obtained a detection limit of 7.8 × 105 particles/mL of Neu-Exo and a recovery rate of 81 % under optimized conditions. ROC curve indicated that the abundance of CD66b+ Neu-Exo could well distinguish GC patients from healthy controls (HC) (AUC > 0.8). Additionally, miR-223-3p was found among the top differentially expressed miRNAs in Neu-Exo and presented superior diagnostic value in gastric cancer. Droplet digital PCR (ddPCR) significantly improved the diagnostic efficiency to differentiate GC patients from HC and benign gastric diseases (BGD) patients (AUC > 0.9).

CONCLUSION

The Dynabeads-based separation and detection system, assisted with ddPCR analysis, provides a promising platform to enrich Neu-Exo and analyze miRNA profile for gastric cancer liquid biopsy.

Encapsulation and assessment of therapeutic cargo in engineered exosomes: a systematic review

Exosomes are nanoscale extracellular vesicles secreted by cells and enclosed by a lipid bilayer membrane containing various biologically active cargoes such as proteins, lipids, and nucleic acids. Engineered exosomes generated through genetic modification of parent cells show promise as drug delivery vehicles, and they have been demonstrated to have great therapeutic potential for treating cancer, cardiovascular, neurological, and immune diseases, but systematic knowledge is lacking regarding optimization of drug loading and assessment of delivery efficacy. This review summarizes current approaches for engineering exosomes and evaluating their drug delivery effects, and current techniques for assessing exosome drug loading and release kinetics, cell targeting, biodistribution, pharmacokinetics, and therapeutic outcomes are critically examined. Additionally, this review synthesizes the latest applications of exosome engineering and drug delivery in clinical translation. The knowledge compiled in this review provides a framework for the rational design and rigorous assessment of exosomes as therapeutics. Continued advancement of robust characterization methods and reporting standards will accelerate the development of exosome engineering technologies and pave the way for clinical studies.

Effective exosomes in breast cancer: focusing on diagnosis and treatment of cancer progression

Breast cancer (BC) is the most prevalent aggressive malignant tumor in women worldwide and develops from breast tissue. Although cutting-edge treatment methods have been used and current mortality rates have decreased, BC control is still not satisfactory. Clarifying the underlying molecular mechanisms will help clinical options. Extracellular vesicles known as exosomes mediate cellular communication by delivering a variety of biomolecules, including proteins, oncogenes, oncomiRs, and even pharmacological substances. These transferable bioactive molecules can alter the transcriptome of target cells and affect signaling pathways that are related to tumors. Numerous studies have linked exosomes to BC biology, including therapeutic resistance and the local microenvironment. Exosomes' roles in tumor treatment resistance, invasion, and BC metastasis are the main topics of discussion in this review.

Colorimetric Detection of HER2-Overexpressing-Cancer-Derived Exosomes in Mouse Urine Using Magnetic-Polydiacetylene Nanoparticles

Breast cancer (BC) is a major global health problem, with ≈20-25% of patients overexpressing human epidermal growth factor receptor 2 (HER2), an aggressive marker, yet access to early detection and treatment varies across countries. A low-cost, equipment-free, and easy-to-use polydiacetylene (PDA)-based colorimetric sensor is developed for HER2-overexpressing cancer detection, designed for use in low- and middle-income countries (LMICs). PDA nanoparticles are first prepared through thin-film hydration. Subsequently, hydrophilic magnetic nanoparticles and HER2 antibodies are sequentially conjugated to them. The synthesized HER2-MPDA can be concentrated and separated by a magnetic field while inheriting the optical characteristics of PDA. The specific binding of HER2 antibody in HER2-MPDA to HER2 receptor in HER2-overexpressing exosomes causes a blue-to-red color change by altering the molecular structure of the PDA backbone. This colorimetric sensor can simultaneously separate and detect HER2-overexpressing exosomes. HER2-MPDA can detect HER2-overexpressing exosomes in the culture medium of HER2-overexpressing BC cells and in mouse urine samples from a HER2-overexpressing BC mouse model. It can selectively isolate and detect only HER2-overexpressing exosomes through magnetic separation, and its detection limit is found to be 8.5 × 108  particles mL-1 . This colorimetric sensor can be used for point-of-care diagnosis of HER2-overexpressing BC in LMICs.

Application of Biosensors in Detecting Breast Cancer Metastasis

Breast cancer has garnered global attention due to its high incidence worldwide, and even more noteworthy is that approximately 90% deaths due to breast cancer are attributed to cancer metastasis. Therefore, the early diagnosis of breast cancer metastasis holds significant importance for reducing mortality outcomes. Biosensors play a crucial role in the early detection of metastatic breast cancer due to their advantages, such as ease of use, portability, and real-time analysis capabilities. This review primarily described various types of sensors for detecting breast cancer metastasis based on biomarkers and cell characteristics, including electrochemical, optical, and microfluidic chips. We offered detailed descriptions of the performance of these various biosensors and made comparisons between them. Furthermore, we described the pathology of breast cancer and summarized commonly used biomarkers for metastatic breast cancer. Finally, we discussed the advantages of current-stage biosensors and the challenges that need to be addressed, as well as prospects for their future development.

Surface immobilization strategies for the development of electrochemical nucleic acid sensors

Following the recent pandemic and with the emergence of cell-free nucleic acids in liquid biopsies as promising biomarkers for a broad range of pathologies, there is an increasing demand for a new generation of nucleic acid tests, with a particular focus on cost-effective, highly sensitive and specific biosensors. Easily miniaturized electrochemical sensors show the greatest promise and most typically rely on the chemical functionalization of conductive materials or electrodes with sequence-specific hybridization probes made of standard oligonucleotides (DNA or RNA) or synthetic analogues (e.g. Peptide Nucleic Acids or PNAs). The robustness of such sensors is mostly influenced by the ability to control the density and orientation of the probe at the surface of the electrode, making the chemistry used for this immobilization a key parameter. This exhaustive review will cover the various strategies to immobilize nucleic acid probes onto different solid electrode materials. Both physical and chemical immobilization techniques will be presented. Their applicability to specific electrode materials and surfaces will also be discussed as well as strategies for passivation of the electrode surface as a way of preventing electrode fouling and reducing nonspecific binding.

Omics-Based Investigations of Breast Cancer

Breast cancer (BC) is characterized by an extensive genotypic and phenotypic heterogeneity. In-depth investigations into the molecular bases of BC phenotypes, carcinogenesis, progression, and metastasis are necessary for accurate diagnoses, prognoses, and therapy assessments in predictive, precision, and personalized oncology. This review discusses both classic as well as several novel omics fields that are involved or should be used in modern BC investigations, which may be integrated as a holistic term, onco-breastomics. Rapid and recent advances in molecular profiling strategies and analytical techniques based on high-throughput sequencing and mass spectrometry (MS) development have generated large-scale multi-omics datasets, mainly emerging from the three "big omics", based on the central dogma of molecular biology: genomics, transcriptomics, and proteomics. Metabolomics-based approaches also reflect the dynamic response of BC cells to genetic modifications. Interactomics promotes a holistic view in BC research by constructing and characterizing protein-protein interaction (PPI) networks that provide a novel hypothesis for the pathophysiological processes involved in BC progression and subtyping. The emergence of new omics- and epiomics-based multidimensional approaches provide opportunities to gain insights into BC heterogeneity and its underlying mechanisms. The three main epiomics fields (epigenomics, epitranscriptomics, and epiproteomics) are focused on the epigenetic DNA changes, RNAs modifications, and posttranslational modifications (PTMs) affecting protein functions for an in-depth understanding of cancer cell proliferation, migration, and invasion. Novel omics fields, such as epichaperomics or epimetabolomics, could investigate the modifications in the interactome induced by stressors and provide PPI changes, as well as in metabolites, as drivers of BC-causing phenotypes. Over the last years, several proteomics-derived omics, such as matrisomics, exosomics, secretomics, kinomics, phosphoproteomics, or immunomics, provided valuable data for a deep understanding of dysregulated pathways in BC cells and their tumor microenvironment (TME) or tumor immune microenvironment (TIMW). Most of these omics datasets are still assessed individually using distinct approches and do not generate the desired and expected global-integrative knowledge with applications in clinical diagnostics. However, several hyphenated omics approaches, such as proteo-genomics, proteo-transcriptomics, and phosphoproteomics-exosomics are useful for the identification of putative BC biomarkers and therapeutic targets. To develop non-invasive diagnostic tests and to discover new biomarkers for BC, classic and novel omics-based strategies allow for significant advances in blood/plasma-based omics. Salivaomics, urinomics, and milkomics appear as integrative omics that may develop a high potential for early and non-invasive diagnoses in BC. Thus, the analysis of the tumor circulome is considered a novel frontier in liquid biopsy. Omics-based investigations have applications in BC modeling, as well as accurate BC classification and subtype characterization. The future in omics-based investigations of BC may be also focused on multi-omics single-cell analyses.

Ratiometric fluorescent detection of exosomal piRNA-823 based on Au NCs/UiO-66-NH2 and target-triggered rolling circle amplification

piR-823 is a newly discovered colorectal cancer marker with high diagnostic efficacy. However, the current quantification methods have complicated operations and high cost, which restrict its clinical application. Herein, a metal-organic framework (MOF) with a UiO-66 prototype structure which supports gold nanoclusters (Au NCs), Au NCs/UiO-66-NH₂, were prepared as a model nanobiosensing platform for ratiometric detection of exosomal piR-823. The rolling circle amplification process provides high sensitivity and the ratiometric detection process ensures good accuracy of the sensor. Such biosensor showed a wide linear range of 0.04-4 pM, and a low detection limit of 10.2 fM towards piR-823. In addition, piR-823 can be used as an effective supplement to carcinoembryonic antigen (CEA) in clinical diagnosis of colorectal cancer. This study not only provides a potentially valuable ratio fluorescence platform involving enzyme catalytic reaction, but also offers a design blueprint for further expansion of nanotechnology in the diverse biological analysis.

Lab-on-a-chip systems for cancer biomarker diagnosis

Lab-on-a-chip (LOC) or micro total analysis system is one of the microfluidic technologies defined as the adaptation, miniaturization, integration, and automation of analytical laboratory procedures into a single instrument or "chip". In this article, we review developments over the past five years in the application of LOC biosensors for the detection of different types of cancer. Microfluidics encompasses chemistry and biotechnology skills and has revolutionized healthcare diagnosis. Superior to traditional cell culture or animal models, microfluidic technology has made it possible to reconstruct functional units of organs on chips to study human diseases such as cancer. LOCs have found numerous biomedical applications over the past five years, including integrated bioassays, cell analysis, metabolomics, drug discovery and delivery systems, tissue and organ physiology and disease modeling, and personalized medicine. This review provides an overview of the latest developments in microfluidic-based cancer research, with pros, cons, and prospects.

Production and Utility of Extracellular Vesicles with 3D Culture Methods

In recent years, extracellular vesicles (EVs) have emerged as promising biomarkers, cell-free therapeutic agents, and drug delivery carriers. Despite their great clinical potential, poor yield and unscalable production of EVs remain significant challenges. When using 3D culture methods, such as scaffolds and bioreactors, large numbers of cells can be expanded and the cell environment can be manipulated to control the cell phenotype. This has been employed to successfully increase the production of EVs as well as to enhance their therapeutic effects. The physiological relevance of 3D cultures, such as spheroids, has also provided a strategy for understanding the role of EVs in the pathogenesis of several diseases and to evaluate their role as tools to deliver drugs. Additionally, 3D culture methods can encapsulate EVs to achieve more sustained therapeutic effects as well as prevent premature clearance of EVs to enable more localised delivery and concentrated exosome dosage. This review highlights the opportunities and drawbacks of different 3D culture methods and their use in EV research.

Conductive Thread-Based Immunosensor for Pandemic Influenza A (H1N1) Virus Detection

Infectious agents such as viruses pose significant threats to human health, being transmitted via direct contact as well as airborne transmission without direct contact, thus requiring rapid detection to prevent the spread of infectious diseases. In this study, we developed a conductive thread-based immunosensor (CT-IS), a biosensor to easily detect the presence of airborne viruses. CT-IS utilizes an antibody that specifically recognizes the HA protein of the pandemic influenza A (pH1N1) virus, which is incorporated into the conductive thread. The antigen-antibody interaction results in increased strain on the conductive thread in the presence of the pH1N1 virus, resulting in increased electrical resistance of the CT-IS. We evaluated the performance of this sensor using the HA protein and the pH1N1 virus, in addition to samples from patients infected with the pH1N1 virus. We observed a significant change in resistance in the pH1N1-infected patient samples (positive: n = 11, negative: n = 9), whereas negligible change was observed in the control samples (patients not infected with the pH1N1 virus; negative). Hence, the CT-IS is a lightweight fiber-type sensor that can be used as a wearable biosensor by combining it with textiles, to detect the pH1N1 virus in a person's vicinity.

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.

Tumor-Derived Exosomes and Their Role in Breast Cancer Metastasis

Breast cancer has been the most common cancer in women worldwide, and metastasis is the leading cause of death from breast cancer. Even though the study of breast cancer metastasis has been extensively carried out, the molecular mechanism is still not fully understood, and diagnosis and prognosis need to be improved. Breast cancer metastasis is a complicated process involving multiple physiological changes, and lung, brain, bone and liver are the main metastatic targets. Exosomes are membrane-bound extracellular vesicles that contain secreted cellular constitutes. The biogenesis and functions of exosomes in cancer have been intensively studied, and mounting studies have indicated that exosomes play a crucial role in cancer metastasis. In this review, we summarize recent findings on the role of breast cancer-derived exosomes in metastasis organotropism and discuss the potential promising clinical applications of targeting exosomes as novel strategies for breast cancer diagnosis and therapy.

Engineered small extracellular vesicles as a versatile platform to efficiently load ferulic acid via an “esterase-responsive active loading” strategy

As nano-drug carriers, small extracellular vesicles (sEVs) have shown unique advantages, but their drug loading and encapsulation efficiency are far from being satisfied, especially for the loading of hydrophilic small-molecule drugs. Inspired by the strategies of active loading of liposomal nanomedicines, pre-drug design and immobilization enzyme, here we developed a new platform, named “Esterase-responsive Active Loading” (EAL), for the efficient and stable drug encapsulation of sEVs. Widely used ferulic acid ester derivatives were chosen as prodrugs based on the EAL of engineered sEVs to establish a continuous transmembrane ion gradient for achieving efficient loading of active molecule ferulic acid into sEVs. The EAL showed that the drug loading and encapsulation efficiency were around 6-fold and 5-fold higher than passive loading, respectively. Moreover, characterization by nano-flow cytometry and Malvern particle size analyzer showed that differential ultracentrifugation combined with multiple types of membrane filtration methods can achieve large-scale and high-quality production of sEVs. Finally, extracellular and intracellular assessments further confirmed the superior performance of the EAL-prepared sEVs-loaded ferulic acid preparation in terms of slow release and low toxicity. Taken together, these findings will provide an instructive insight into the development of sEV-based delivery systems.

Novel Pumping Methods for Microfluidic Devices: A Comprehensive Review

This review is an account of methods that use various strategies to control microfluidic flow control with high accuracy. The reviewed systems are divided into two large groups based on the way they create flow: passive systems (non-mechanical systems) and active (mechanical) systems. Each group is presented by a number of device fabrications. We try to explain the main principles of operation, and we list advantages and disadvantages of the presented systems. Mechanical systems are considered in more detail, as they are currently an area of increased interest due to their unique precision flow control and "multitasking". These systems are often applied as mini-laboratories, working autonomously without any additional operations, provided by humans, which is very important under complicated conditions. We also reviewed the integration of autonomous microfluidic systems with a smartphone or single-board computer when all data are retrieved and processed without using a personal computer. In addition, we discuss future trends and possible solutions for further development of this area of technology.

Extracellular vesicle isolation, purification and evaluation in cancer diagnosis

Strategies for non-invasive biomarker discovery in early detection of cancer are an urgent need. Extracellular vesicles (EVs) have generated increasing attention from the scientific community and are under intensive investigations due to their unique biological profiles and their non-invasive nature. EVs are membrane-enclosed vesicles with variable sizes and function. Such vesicles are actively secreted from multiple cell types and are considered as key vehicles for inter-cellular communications and signalling. The stability and potential to easily cross biological barriers enable EVs for exerting durable effects on target cells. These along with easy access to such vesicles, the consistent secretion from tumour during all stages of tumorigenesis and their content providing a reservoir of molecules as well as mirroring the identity of the cell of origin are virtues that have made EVs appealing to be assessed in liquid biopsy approaches and for using as a promising resource of biomarkers in cancer diagnosis and therapy and monitoring targeted cancer therapy. Early detection of EVs will guide time-scheduled personalised therapy. Surveying reliable and sensitive methods for rapid isolation of EVs from biofluids, the purity of isolated vesicles and their molecular profiling and marker specification for clinical translation in patients with cancer are issues in the area and the hot topics of many recent studies. Here, the focus is over methods for EV isolation and stratification for digging more information about liquid biopsy-based diagnosis. Extending knowledge regarding EV-based strategies is a key to validate independent patient follow-up for cancer diagnosis at early stages and inspecting the efficacy of therapeutics.

Electrochemical nano-sensing interface for exosomes analysis and cancer diagnosis

Exosomes are a class of the nanosized extracellular vesicles, which have emerged as representative liquid biopsy biomarkers. To date, the electrochemical nanosensors are of great significance in the exosome detection with the advantages of easy operation, high accuracy and reliable repeatability. Especially, the growing field of nano interface has provided the electrochemical sensing platforms for the accurate exosomes analysis. The incorporation of multiple nanomaterials can take advantages and synergistic properties of functional units. So, based on the integration of with nanomaterial-based signal transduction and specific biorecognition, the nano-sensing interface provides excellent electrochemical features owing to rapid mass transport and excellent conductivity. The nano-sensing interface with a wide variety of morphologies and structure also provides the large active surface area for the immobilization of bio-capturing agents. Furthermore, through the design of nanostructured electrode array, the efficiency of transducer can be greatly improved. It should be noticed that the elaboration of a proper sensor requires the profound knowledge of the nano-sensing interface. Therefore, this article presents a review of the recent advance in exosomes detection based on the electrochemical nano-sensing interface, including electrochemical analysis principles, exosome sensing mechanisms, nano-interface construction strategies, as well as the typical diagnosis application. In particular, the article is focused on the exploration of the various electrochemical sensing performance of nano-interface in the exosome detection. We have also prospected the future trend and challenge of the electrochemical nano-sensing interface for exosomes analysis in clinical cancer diagnosis.

A rational design of a cascaded DNA circuit for nanoparticle assembly and its application in the discrimination of single-base changes

In the field of dynamic DNA nanotechnology, a designable DNA assembly circuit based on the toehold-mediated strand displacement reaction has demonstrated its ability to program the self-assembly of nanoparticles. However, the laborious work for the modification of nanoparticles with oligonucleotides, the long assembly time, and the circuit leakage prevent its further and scalable applications. To this end, cascaded circuits composed of two recycling circles are rationally designed in this study. Through the pre-initiation of the autonomous reaction, nanoparticles as sensing elements and no additionally exposed bases on the substrate hybridized with fuel strand, the real assembly time and signal leakage for diagnostic application can be effectively reduced and eliminated, thus offering a promising methodology for future point-of-care testing.

Isothermal amplification-mediated lateral flow biosensors for in vitro diagnosis of gastric cancer-related microRNAs

MicroRNAs (miRNAs) are important diagnostic and prognostic biomarkers for various tumors. Currently, many diagnostic systems have been developed to detect miRNAs, but simple techniques for detecting miRNAs are still required. Recently, we reported that the expression of miRNA-135b is upregulated in gastric epithelial cells during gastric inflammation and carcinogenesis. Our aim was to develop an in vitro diagnostic platform to analyze the expression of gastric cancer-related biomarkers in the blood. The diagnostic platform comprised an isothermal amplification-based lateral flow biosensor (IA-LFB) that enables easy diagnosis of gastric cancer through visual observation. In this platform, trace amounts of biomarkers are isothermally amplified through rolling circle amplification (RCA), and the amplified product is grafted to the LFB. The performance of the IA-LFB was confirmed using RNAs extracted from in vitro and in vivo models. The platform could detect target miRNAs within 3 h with excellent sensitivity and selectivity. In particular, the IA-LFB could detect the overexpression of gastric cancer-related markers (miRNA-135b and miRNA-21) in RNAs extracted from the blood of patients with various stages (stages 1-4) of gastric cancer compared to that in healthy volunteers. Therefore, IA-LFB is a simple and sensitive in vitro diagnostic system for detecting gastric cancer-related biomarkers and can contribute to the early diagnosis and prognosis monitoring of gastric cancer. Furthermore, this technology can be applied to systems that can detect multiple biomarkers related to various diseases (such as infectious and genetic diseases).

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

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

Microfluidic Point-of-Care (POC) Devices in Early Diagnosis: A Review of Opportunities and Challenges

The early diagnosis of infectious diseases is critical because it can greatly increase recovery rates and prevent the spread of diseases such as COVID-19; however, in many areas with insufficient medical facilities, the timely detection of diseases is challenging. Conventional medical testing methods require specialized laboratory equipment and well-trained operators, limiting the applicability of these tests. Microfluidic point-of-care (POC) equipment can rapidly detect diseases at low cost. This technology could be used to detect diseases in underdeveloped areas to reduce the effects of disease and improve quality of life in these areas. This review details microfluidic POC equipment and its applications. First, the concept of microfluidic POC devices is discussed. We then describe applications of microfluidic POC devices for infectious diseases, cardiovascular diseases, tumors (cancer), and chronic diseases, and discuss the future incorporation of microfluidic POC devices into applications such as wearable devices and telemedicine. Finally, the review concludes by analyzing the present state of the microfluidic field, and suggestions are made. This review is intended to call attention to the status of disease treatment in underdeveloped areas and to encourage the researchers of microfluidics to develop standards for these devices.