Recent advances in the detection of multiple microRNAs

DNA-mediated precise regulation of SERS hotspots for biosensing and bioimaging

Surface-enhanced Raman scattering (SERS) is a powerful analytical technique, where the creation of "hotspots" holds the key to unlocking sensitive, reproducible and reliable performance. DNA nanostructures, known for their unique predictability and exceptional programmability, have emerged as promising tools for the controllable assembly and precise regulation of SERS hotspots. In recent years, the application of DNA nanotechnology in the regulation of SERS hotspots has emerged as a research focus, but a comprehensive summary of this field is still lacking. This review begins by elucidating the mechanisms of localized surface plasmon resonance (LSPR) coupling and SERS enhancement, providing a theoretical foundation for the design principles and assembly strategies for SERS hotspots. Following this, general approaches for assembling static SERS hotspots using DNA structures of different dimensions as linkers or templates are explored. Subsequently, we delve into dynamic regulation strategies for SERS hotspots mediated by DNA structures, focusing on structural reconfiguration driven by DNA hybridization, toehold-mediated strand displacement (TMSD), and enzyme-catalyzed DNA allostery, and then summarize recent examples of DNA-mediated hotspot regulation in biosensing and bioimaging applications. Finally, we discuss future perspectives associated with the DNA-mediated precise regulation of SERS hotspots, underscoring the imperative for enhanced scalability, uniformity, and integration to pave the way for real-world applications.

Dual miRNAs Imaging Platform Based on HRCA-Cas12a by Replacing PAM with Bubble to Reduce False Positive

Detection and imaging of dual miRNAs based on AND logic gates can improve the accuracy of the early diagnosis of disease. However, a single target may lead to false positive. Hence, this work rationally integrates hyperbranched rolling circle amplification (HRCA) with Cas12a by replacing the PAM sequence with a bubble to sensitively detect and image miRNA-10b and miRNA-21 based on the AND logic gate. When miRNA-10b and miRNA-21 are both present, the two padlocks are linked into circular DNA as a template for RCA. Long ssDNA products are generated under the catalysis of phi29 DNA polymerase, which are cis-cleaved by Cas12a and activated the trans-cleavage of Cas12a to generate fluorescent signals. Subsequently, the primer hybridizes with the products of cis-cleavage and is extended as the dsDNA substrate of Cas12a to produce more fluorescent signals. However, a single target produces significant fluorescent signals leading to false positive due to the presence of protospacer adjacent motif (PAM) on the padlock. After PAM is removed from the padlock, the primer and RCA products form bubbles to replace PAM, which activate Cas12a without affecting sensitivity and reduce false positive. The introduction of a primer enables the second utilization of phi29 and Cas12a, increasing the signal-to-noise ratio. HRCA and Cas12a exhibit optimal activity in the T4 ligase buffer, achieving one-pot detection of dual miRNAs. In addition, the HRCA-Cas12a method enables the intracellular visualization of dual miRNAs. It exhibits the ability to distinguish different types of cancer cells based on the expression level of miRNAs.

Electrochemical-Enhanced Charge State Modulation of Nitrogen-Vacancy Centers for Ultrasensitive Biodetection of MicroRNA-155

Sensitive and accurate miRNA detection is important in cancer diagnosis but remains challenging owing to the essential features of miRNAs, such as their small size, high homology, and low abundance. This work proposes a novel electrochemical (EC)-enhanced quantum sensor achieving quantitative detection of miRNA-155 with simultaneous EC sensing. Specifically, fluorescent nanodiamonds/MXene nanocomposites were synthesized and modified with dual-mode signal labels, enabling miRNA-155 concentration measurement via T1 relaxation time of nitrogen-vacancy (NV) centers and EC signals. Quantum sensing was enhanced via external voltage during the EC process, which modulated the negatively charged state of the NV centers, thereby improving the sensitivity and accuracy of miRNA-155 detection. EC sensing improved the accuracy and reliability of miRNA-155 detection while enhancing quantum sensing. The limit of detection (LOD) of the EC-enhanced quantum biosensor reached 10.0 aM, nearly 106 and 10 times lower than the reported LODs of a quantum sensor using bulk diamond and fluorescent sensors, respectively. The LOD of EC sensing was 2.6 aM, aligning with previous reports. The findings of the study indicated that quantum sensing combined with EC sensing can achieve ultrasensitive miRNA-155 detection with high accuracy and reliability, providing an advanced approach for early cancer diagnosis.

A Comprehensive Review on Capillary Electrophoresis-Mass Spectrometry in Advancing Biomolecular Research

This review provides an in-depth exploration of capillary electrophoresis-mass spectrometry (CE-MS) in biomolecular research from 2020 to 2024. CE-MS emerges as a versatile and powerful tool due to its numerous advantages, facilitating the analysis of various biomolecules, including proteins, peptides, oligonucleotides, and other metabolites, such as lipids, carbohydrates, or amines, among others. The review extends to various CE modes and interfaces for the CE-MS coupling, offering comprehensive insights into their applications within biomolecular research. Furthermore, it effectively summarizes the conditions employed in CE-MS while also addressing critical aspects such as sample preparation requirements. Despite its advantages, the review highlights a gap between discovery and practical implementation, underscoring the need for large-scale validation and method standardization to fully realize the potential of CE-MS in biomolecular research.

A bivariate fluorescence biosensor based on Janus DNA nanoarchitecture-loaded dual-emissive Ag nanoclusters as bi-responsive signaling reporters

Constructing label-free bivariate fluorescence biosensor would be intriguing and desired for the recognizable and accurate detection of two specific DNA segments, yet the design of functional DNA structures with low overlapped interference might be challenging. Herein in this work, a double-faced Janus DNA nanoarchitecture (JDNA) with bi-responsive recognition regions on opposite sides was assembled, which consisted of two substrate strands and two template strands for loading green-/red-emissive Ag nanoclusters (gAgNC and rAgNC) as bivariate signaling reporters. Of note, the hybridized double helix in the middle rationally oriented two flank faces and stabilized the rigid conformation of JDNA, while the template sequences of bicolor clusters were blocked to minimize non-specific background leakage. Upon inputting two targets, the discernible hairpins lost their hairpin structures due to forming two dsDNA complexes. They were executed to simultaneously invade JDNA for activating two individual target-recycled strand displacement (TRSD) events, guiding signal transduction and efficient amplification. Consequently, the clustering templates were unlocked via the tailored conformation switch of JDNA, in which gAgNC and rAgNC were in situ synthesized in two diagonal positions, thereby significantly emitting bi-responsive signal without cross interference. Benefited from the logic integration of double-faced JDNA and TRSD, a label-free, sensitive and specific bivariate fluorescence approach was developed, which would open a new avenue for the potential application in biosensing and bioanalysis.

An advanced 3D DNA nanoplatform for spatiotemporally confined enhanced dual-mode biosensing MicroRNA in cancer cell

Dual-mode signal output platforms have demonstrated considerable promise due to their improved anti-interference capability and inherent signal self-correction. Nevertheless, traditional discrete-distributed signal probes often encounter significant drawbacks, including limited mass transfer efficiency, diminished signal strength, and instability in intricate biochemical environments. In response to these challenges, a scalable and hyper-compacted 3D DNA nanoplatform resembling "periodic focusing heliostat" has been developed for synergistically enhanced fluorescence (FL) and surface-enhanced Raman spectroscopy (SERS) biosensing of miRNA in cancer cells. Our approach utilized a distinctive assembly strategy integrating gold nanostars (GNS) as fundamental "heliostat units" linked by palindromic DNA sequences to facilitate each other hand-in-hand cascade alignment and condensed into large scale nanostructures. This configuration was further augmented by the incorporation of gold nanoparticles (GNP) via strong Au-S bonds, resulting in a sturdy framework for improved signal transduction. The initiation of this assembly process was mediated by the hybridization of dsDNA to miRNA-21, which served as a primer for polymerization and nicking reactions, thus generating a multifunctional T2 probe. This probe is intricately designed with three distinct parts: a 3'-palindromic end for structural integrity, a central region for capturing SERS-active probes (Cy3-P2), and a 5'-segment for attaching fluorescence reporters. Upon integration T2 into the GNS-based heliostat unit, it promotes palindromic arm-induced aggregation and plasma exciton coupling between plasma nanoparticles and signal transduction tags. This clustered arrangement creates a high-density "hot spot" array that maximizes the local electromagnetic fields necessary for enhanced SERS and FL response. This superstructure supports enhanced aggregation-induced signal amplification for both SERS and FL, offering exceptional sensitivity with LOD as low as 0.0306 pM and 0.409 pM. The efficacy of this method was demonstrated in the evaluation of miRNA-21 in various cancer cell lines.

Indirect and sensitive determination of microRNAs by magnetic field-assisted capillary sieving electrophoresis combined with catalytic hairpin assembly

To determine multiple microRNAs (miRNAs) from cells simultaneously is essential for understanding biological functions. Capillary electrophoresis (CE) can simultaneously determine multiple miRNAs by separation. Nevertheless, similar lengths and low concentrations in cells make miRNAs hard to separate and detect. In this study, CE with laser-induced fluorescence detection was combined with catalytic hairpin assembly (CHA) to determine three miRNAs, miR-21, miR-31, and miR-122. The amplification products of CHA, which were DNA duplexes, were designed to have different lengths for different miRNAs. This allowed for easy separation of the duplexes of different miRNAs by CE. The indirect determination of miRNAs was then achieved by separating and detecting these duplexes. A magnetic field was first applied on the capillary sieving electrophoresis to assist in the separation of the duplexes. Under the optimal conditions, the three duplexes could be completely separated within 2.5 min with the detection limits of miRNAs in the range 1.12-4.05 × 10-15 M. MiR-21 and miR-31 were successfully determined from Hela cells, while miR-122 was determined from chicken livers by this method. The recoveries ranged from 97.5% to 118%. The developed method was sensitive and reliable for miRNA determination.

Genetic Alchemy unveiled: MicroRNA-mediated gene therapy as the Artisan craft in the battlefront against hepatocellular carcinoma-a comprehensive chronicle of strategies and innovations

Investigating therapeutic miRNAs is a rewarding endeavour for pharmaceutical companies. Since its discovery in 1993, our understanding of miRNA biology has advanced significantly. Numerous studies have emphasised the disruption of miRNA expression in various diseases, making them appealing candidates for innovative therapeutic approaches. Hepatocellular carcinoma (HCC) is a significant malignancy that poses a severe threat to human health, accounting for approximately 70%-85% of all malignant tumours. Currently, the efficacy of several HCC therapies is limited. Alterations in various biomacromolecules during HCC progression and their underlying mechanisms provide a basis for the investigation of novel and effective therapeutic approaches. MicroRNAs, also known as miRNAs, have been identified in the last 20 years and significantly impact gene expression and protein translation. This atypical expression pattern is strongly associated with the onset and progression of various malignancies. Gene therapy, a novel form of biological therapy, is a prominent research area. Therefore, miRNAs have been used in the investigation of tumour gene therapy. This review examines the mechanisms of action of miRNAs, explores the correlation between miRNAs and HCC, and investigates the use of miRNAs in HCC gene therapy.

Detection of Single Nucleotide Polymorphisms of Circulating Tumor DNA by Strand Displacement Amplification Coupled with Liquid Chromatography

The detection of multiple single nucleotide polymorphisms (SNPs) of circulating tumor DNA (ctDNA) is still a great challenge. In this study, we designed enzyme-assisted nucleic acid strand displacement amplification combined with high-performance liquid chromatography (HPLC) for the simultaneous detection of three ctDNA SNPs. First, the trace ctDNA could be hybridized to the specially designed template strand, which initiated the strand displacement nucleic acid amplification process under the synergistic action of DNA polymerase and restriction endonuclease. Then, the targets would be replaced with G-quadruplex fluorescent probes with different tail lengths. Finally, the HPLC-fluorescence assay enabled the separation and quantification of multiple signals. Notably, this method can simultaneously detect both the wild type (WT) and mutant type (MT) of multiple ctDNA SNPs. Within a linear range of 0.1 fM-0.1 nM, the detection limits of BRAF V600E-WT, EGFR T790M-WT, and KRAS 134A-WT and BRAF V600E-MT, EGFR T790M-MT, and KRAS 134A-MT were 29, 31, and 11 aM and 22, 29, and 33 aM, respectively. By using this method, the mutation rates of multiple ctDNA SNPs in blood samples from patients with lung or breast cancer can be obtained in a simple way, providing a convenient and highly sensitive analytical assay for the early screening and monitoring of lung cancer.

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) modified metal-organic frameworks boosting carbon dots electrochemiluminescence emission for sensitive miRNA detection

Highly efficient luminescent materials play an important role in electrochemiluminescence (ECL) biosensing systems. Herein, the poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) modified carbon dots (CDs)/zeolitic imidazolate framework-8 (ZIF-8) compositing metal-organic frameworks (MOFs) materials with excellent luminescence performance were prepared as the ECL emitters for biosensing application. In this novel ternary composites, CDs were used as emitters, ZIF-8 was used as a carrier, and the luminescent performance was finally improved by introducing PEDOT:PSS to improve the conductivity of the nanomaterials. As a result, CDs/PEDOT:PSS/ZIF-8 exhibited an approximately 8 times ECL intensity compared to CDs alone. By further modifying with AuNPs, the enhancement factor reached ≈10 in reference to the individual CDs. After combining with a DNAzyme-based two-cycle target amplification principle, an ECL biosensor was constructed to achieve high-sensitivity detection of miRNA-21 with a detection limit of 50 aM. The biosensor also demonstrated desirable selectivity, excellent stability, and quantitative ability for human serum target detection. Overall, these findings not only provide a promising pathway for high luminous efficiency ECL emitters synthesis, but also provide a platform for ultrasensitive miRNA sensing.

Deep Learning Promotes Profiling of Multiple miRNAs in Single Extracellular Vesicles for Cancer Diagnosis

Extracellular vesicle microRNAs (EV miRNAs) are critical noninvasive biomarkers for early cancer diagnosis. However, accurate cancer diagnosis based on bulk analysis is hindered by the heterogeneity among EVs. Herein, we report an approach for profiling single-EV multi-miRNA signatures by combining total internal reflection fluorescence (TIRF) imaging with a deep learning (DL) algorithm for the first time. This innovative technique allows for the precise characterization of EV miRNAs at the single-vesicle level, overcoming the challenges posed by EV heterogeneity. TIRF with high resolution and a signal-to-noise ratio can simultaneously detect multi-miRNAs in situ in individual EVs. DL algorithm avoids complicated and inaccurate artificial feature extraction, achieving automated high-resolution image analysis. Using this approach, we reveal that the main variation of EVs from 5 cancer cells and normal plasma is the triple-positive EV subpopulation, and the classification accuracy of single triple-positive EVs from 6 sources can reach above 95%. In the clinical cohort, 20 patients (5 lung cancer, 5 breast cancer, 5 cervical cancer, and 5 colon cancer) and 5 healthy controls are predicted with an overall accuracy of 100%. This single-EV strategy provides new opportunities for exploring more specific EV biomarkers to achieve cancer diagnosis and classification.

Label-free fluorescence detection of human 8-oxoguanine DNA glycosylase activity amplified by target-induced rolling circle amplification

BACKGROUND

Human 8-oxoG DNA glycosylase 1 (hOGG1) is one of the important members of DNA glycosylase for Base excision repair (BER), the abnormal activity of which can lead to the failure of BER and the appearance of various diseases, such as breast cancer, bladder cancer, Parkinson's disease and lung cancer. Therefore, it is important to detect the activity of hOGG1. However, traditional detection methods suffer from time consuming, complicated operation, high false positive results and low sensitivity. Thus, it remains a challenge to develop simple and sensitive hOGG1 analysis strategies to facilitate early diagnosis and treatment of the relative disease.

RESULTS

A target-induced rolling circle amplification (TIRCA) strategy for label-free fluorescence detection of hOGG1 activity was proposed with high sensitivity and specificity. The TIRCA strategy was constructed by a hairpin probe (HP) containing 8-oxoG site and a primer probe (PP). In the presence of hOGG1, the HP transformed into dumbbell DNA probe (DDP) after the 8-oxoG site of which was removed. Then the DDP formed closed circular dumbbell probe (CCDP) by ligase. CCDP could be used as amplification template of RCA to trigger RCA. The RCA products containing repeated G4 sequences could combine with ThT to produce enhanced fluorescence, achieving label-free fluorescence sensing of hOGG1. Given the high amplification efficiency of RCA and the high fluorescence quantum yield of the G4/ThT, the proposed TIRCA achieved highly sensitive measurement of hOGG1 activity with a detection limit of 0.00143 U/mL. The TIRCA strategy also exhibited excellent specificity for hOGG1 analysis over other interference enzymes.

SIGNIFICANCE

This novel TIRCA strategy demonstrates high sensitivity and high specificity for the detection of hOGG1, which has also been successfully used for the screening of inhibitors and the analysis of hOGG1 in real samples. We believe that this TIRCA strategy provides new insight into the use of the isothermal nucleic acid amplification as a useful tool for hOGG1 detection and will play an important role in disease early diagnosis and treatment.

Au nano-cone array for SERS detection of associated miRNA in lymphoma patients

Based on Au nano-cone array (Au-NCA) and a three-segment hybridization strategy, a novel SERS biosensor is proposed for the ultrasensitive detection of the microRNA miR-21. The uniform, stable, and reproducible Au-NCA was prepared by the single-layer colloidal ball template method. Subsequently, the target was hybridized with sequence 2. The resulting target-sequence 2 complex was then hybridized with sequence 1 anchored on Au-NCA. Thus, a three-segment sequence complex was formed. SERS measurements can be performed without the need for complex purification and amplification steps. Due to the ability of miR-21 to perform specific complementary hybridization with two sequences, SERS biosensors have superior specificity for miR-21 without interference from other miRNAs. Under the optimal conditions, the SERS biosensor was applied and the limit of detection (LOD) was as low as 3.02 aM. This method has been successfully used to the detection of miR-21 in the serum of lymphoma patients and healthy volunteers. The results are consistent with the traditional test methods. Therefore, this novel SERS biosensor shows excellent clinical translational potential in the detection of lymphoma.

A cascade signal-amplified fluorescent biosensor combining APE1 enzyme cleavage-assisted target cycling with rolling circle amplification

A cascade signal-amplified fluorescent biosensor was developed for miRNA-21 detection by combining APE1 enzyme-assisted target recycling and rolling circle amplification strategy. A key feature of this biosensor is its dual-trigger mechanism, utilizing both tumor-endogenous miRNA-21 and the APE1 enzyme in the initial amplification step, followed by a second rolling circle amplification reaction. This dual signal amplification cascade significantly enhanced sensitivity, achieving a detection limit of 3.33 pM. Furthermore, this biosensor exhibited excellent specificity and resistance to interference, allowing it to effectively distinguish and detect the target miRNA-21 in the presence of multiple interfering miRNAs. Moreover, the biosensor maintained its robust detection capabilities in a 10% serum environment, demonstrating its potential for clinical disease diagnosis applications.

LC-MS-Based Direct Quantification of MicroRNAs in Rat Blood

MicroRNA (miRNA) has recently garnered significant research attention, owing to its potential as a diagnostic biomarker and therapeutic target. Liquid chromatography-mass spectrometry (LC-MS) offers accurate quantification, multiplexing capacity, and high compatibility with various matrices. These advantages establish it as a preferred technique for detecting miRNA in biological samples. In this study, we presented an LC-MS method for directly quantifying seven miRNAs (rno-miR-150, 146a, 21, 155, 223, 181a, and 125a) associated with immune and inflammatory responses in rat whole blood. To ensure miRNA stability in the samples and efficiently purify target analytes, we compared Trizol- and proteinase K-based extraction methods, and the Trizol extraction proved to be superior in terms of analytical sensitivity and convenience. Chromatographic separation was carried out using an oligonucleotide C18 column with a mobile phase composed of N-butyldimethylamine, 1,1,1,3,3,3-hexafluoro-2-propanol, and methanol. For MS detection, we performed high-resolution full scan analysis using an orbitrap mass analyzer with negative electrospray ionization. The established method was validated by assessing its selectivity, linearity, limit of quantification, accuracy, precision, recovery, matrix effect, carry-over, and stability. The proposed assay was then applied to simultaneously monitor target miRNAs in lipopolysaccharide-treated rats. Although potentially less sensitive than conventional methods, such as qPCR and microarray, this direct-detection-based LC-MS method can accurately and precisely quantify miRNA. Given these promising results, this method could be effectively deployed in various miRNA-related applications.

Three-dimensional ordered DNA network constructed by a biomarker pair for accurate monitoring of colorectal cancer

Precise and early screening of colorectal cancer (CRC) is one crucial yet challenging task for its treatment, and the analysis of multi-targets of CRC in a single assay with high accuracy is essential for pathological research and clinical diagnosis. Here, a CRC-related biomarker pair, microRNA-211 (miRNA-211) and H₂S, was detected by constructing a three-dimensional (3D) ordered DNA network. First, trace amount of miRNA-211 could initiate a hybridization chain reaction-based amplification process. A highly ordered 3D DNA network was formed based on the organized assembly of DNA-cube frameworks that were constructed by DNA origamis and Ag nanoparticles (NPs) encapsulated inside. In the presence of the H₂S, Ag NPs within the network can be etched to generate Ag₂S quantum dots, which could be better visualized in fluorescence in situ cell imaging. Using the 3D DNA ordered network as the sensing platform, it can acquire dual analysis of biomolecule (miRNA-211) and inorganic gas (H₂S) in vitro, overcoming the limitations of single type of biomarker detection in a single assay. This assay achieved a wide linearity range of H₂S from 0.05 to 10 μM, and exhibited a low limit of detection of 4.78 nM. This strategy allows us to acquire the spatial distributions of H₂S and miRNA expression levels in living CRC cells simultaneously, providing a highly sensitive and selective tool for early screening and monitoring of CRC.

Bidirectional motivated bimodal isothermal strand displacement amplifier with a table tennis-like movement for the ultrasensitive fluorescent and colorimetric detection of depression-related microRNA

An increasing number of studies have highlighted the potential of microRNAs (miRNAs) as physiological indicators of major depressive disorder (MDD). Herein, we developed a bidirectional-motivated bimodal isothermal strand displacement amplifier (BB-ISDA) for the ultrasensitive fluorescent and colorimetric detection of MDD-related miRNA-132. In the BB-ISDA system, a pair of functionalized hairpin probes (HP1 and HP2) with nicking recognition sites are designed to recognize target miRNA. The recognition of target miRNA by HP1 (or HP2) generates copious numbers of nicked triggers by HP1 (or HP2)-based ISDA to recognize HP2 (or HP1) by autonomous strand polymerization, cleavage, and displacement, which in turn induces the subsequent generation of copious numbers of nicked G-quadruplex triggers by HP2 (or HP1)-based ISDA to recognize HP1 (or HP2) along a same line. After many cycles, this bidirectional motivated table-tennis-like movement amplifies the fluorescent signal from HP1 and the colorimetric signal from HP2, simultaneously. The dual-signal output pattern was cross-validated for sensing miRNA-132. Each of the detection modal shows the capability for qualitative and quantitative detection of miRNA-132 with high sensitivity and specificity. The adaptability of the bimodal mechanism was verified via the detection of target miRNA-132 from clinical human blood samples. We envision that this BB-ISDA with dual-signal output for accurate and reliable analysis of miRNA is promising for the molecular diagnosis of human mental diseases.

Self-Generation of Distinguishable Fluorescent Probes via a One-Pot Process for Multiple MicroRNA Detection by Liquid Chromatography

To address the challenge of signal production and separation for multiple microRNA (miRNA) detection, in this work, a "one-pot" process to self-generate distinguishable fluorescent probes was developed. Based on a long and short probe amplification strategy, the generated G-quadruplex fluorescent dye-free probes can be separated and detected by a high-performance liquid chromatography-fluorescence platform. The free hairpin probes enriched in guanine with different lengths and base sequences were designed and could be opened by the target miRNAs (miRNA-10b, miRNA-21, and miRNA-210). Cleaved G-quadruplex probes with fluorescent signal could be generated in a one-pot process after a duplex-specific nuclease-based cleavage, and the detection of multiple miRNAs could be realized in one run. No solid nanomaterials were applied in the assay, which avoided the blocking of the column. Moreover, without modification of expensive fluorescein, the experimental cost was greatly reduced. The one-pot reaction process also eliminated tedious preparation steps and suggested feasibility of automation. The limits of detection of miRNA-10b, miRNA-21, and miRNA-210 were 2.19, 2.20, and 2.75 fM, respectively. Notably, this method was successfully applied to multiplex detection of miRNAs in serum samples from breast cancer patients within 30 min.

Multiplexed Profiling of Extracellular Vesicles for Biomarker Development

Extracellular vesicles (EVs) are cell-derived membranous particles that play a crucial role in molecular trafficking, intercellular transport and the egress of unwanted proteins. They have been implicated in many diseases including cancer and neurodegeneration. EVs are detected in all bodily fluids, and their protein and nucleic acid content offers a means of assessing the status of the cells from which they originated. As such, they provide opportunities in biomarker discovery for diagnosis, prognosis or the stratification of diseases as well as an objective monitoring of therapies. The simultaneous assaying of multiple EV-derived markers will be required for an impactful practical application, and multiplexing platforms have evolved with the potential to achieve this. Herein, we provide a comprehensive overview of the currently available multiplexing platforms for EV analysis, with a primary focus on miniaturized and integrated devices that offer potential step changes in analytical power, throughput and consistency.

Nanomaterial-Based Fluorescence Resonance Energy Transfer (FRET) and Metal-Enhanced Fluorescence (MEF) to Detect Nucleic Acid in Cancer Diagnosis

Nucleic acids, including DNA and RNA, have received prodigious attention as potential biomarkers for precise and early diagnosis of cancers. However, due to their small quantity and instability in body fluids, precise and sensitive detection is highly important. Taking advantage of the ease-to-functionality and plasmonic effect of nanomaterials, fluorescence resonance energy transfer (FRET) and metal-enhanced fluorescence (MEF)-based biosensors have been developed for accurate and sensitive quantitation of cancer-related nucleic acids. This review summarizes the recent strategies and advances in recently developed nanomaterial-based FRET and MEF for biosensors for the detection of nucleic acids in cancer diagnosis. Challenges and opportunities in this field are also discussed. We anticipate that the FRET and MEF-based biosensors discussed in this review will provide valuable information for the sensitive detection of nucleic acids and early diagnosis of cancers.