An electrochemical biosensor based on ARGET ATRP with DSN-assisted target recycling for sensitive detection of tobacco mosaic virus RNA

Simultaneous detection of breast cancer biomarkers HER2 and miRNA-21 based on duplex-specific nuclease signal amplification

The detection of a single biomarker is prone to false negative or false positive results. Simultaneous analysis of two biomarkers can greatly improve the accuracy of diagnosis. In this work, we designed a new method for coinstantaneous detection of two breast cancer biomarkers miRNA-21 and HER2 using the properties of duplex-specific nuclease (DSN). Cy5-labeled DNA1 and FAM-labeled DNA2 are used as signal probes to distinguish the two signals. When the sample contains the targets HER2 and miRNA-21, HER2 binds to the HER2 aptamer on the double-stranded DNA2, while miRNA-21 binds to the complementary DNA1. Then, DSN enzyme is added to cut the DNA probes adsorbed on the HER2 aptamer and miRNA-21, releasing the fluorescent groups, which can be readsorbed to the empty sites, thus repeating the cutting of the probes and producing an exponential signal amplification with two distinct fluorescent signals. The detection limits of miRNA-21 and HER2 are 1.12 pM and 0.36 ng mL-1, respectively, with linear ranges of 5 pM to 50 pM and 1 ng mL-1 to 15 ng mL-1. The method was validated in real biological samples, providing a new approach for synchronous analysis of important markers in breast cancer.

Recent advances in the applications of DNA frameworks in liquid biopsy: A review

Cancer is one of the serious threats to public life and health. Early diagnosis, real-time monitoring, and individualized treatment are the keys to improve the survival rate and prolong the survival time of cancer patients. Liquid biopsy is a potential technique for cancer early diagnosis due to its non-invasive and continuous monitoring properties. However, most current liquid biopsy techniques lack the ability to detect cancers at the early stage. Therefore, effective detection of a variety of cancers is expected through the combination of various techniques. Recently, DNA frameworks with tailorable functionality and precise addressability have attracted wide spread attention in biomedical applications, especially in detecting cancer biomarkers such as circulating tumor cells (CTCs), exosomes and circulating tumor nucleic acid (ctNA). Encouragingly, DNA frameworks perform outstanding in detecting these cancer markers, but also face some challenges and opportunities. In this review, we first briefly introduced the development of DNA frameworks and its typical structural characteristics and advantages. Then, we mainly focus on the recent progress of DNA frameworks in detecting commonly used cancer markers in liquid-biopsy. We summarize the advantages and applications of DNA frameworks for detecting CTCs, exosomes and ctNA. Furthermore, we provide an outlook on the possible opportunities and challenges for exploiting the structural advantages of DNA frameworks in the field of cancer diagnosis. Finally, we envision the marriage of DNA frameworks with other emerging materials and technologies to develop the next generation of disease diagnostic biosensors.

A highly sensitive fluorescence sensor for tobacco mosaic virus RNA based on DSN cycle and ARGET ATRP double signal amplification

Early and sensitive detection of tobacco mosaic virus (TMV) is of great significance for improving crop yield and protecting germplasm resources. Herein, we constructed a novel fluorescence sensor to detect TMV RNA (tRNA) through double strand specific nuclease (DSN) cycle and activator regenerative electron transfer atom transfer radical polymerization (ARGET ATRP) dual signal amplification strategy. The hairpin DNA complementarily paired with tRNA was used as a recognition unit to specifically capture tRNA. By the double-stranded DNA hydrolyzed with DSN, tRNA is released to open more hairpin DNA, and more complementary DNA (cDNA) is bound to the surface of the magnetic beads (MBs) to achieve the first amplification. After binding with the initiator, the cDNA employed ARGET ATRP to attach more fluorescent signal molecules to the surface of MBs, thus achieving the second signal amplification. Under the optimal experimental conditions, the logarithm of fluorescence intensity versus tRNA concentration showed a good linear relationship in the range of 0.01-100 pM, with a detection limit of 1.03 fM. The limit of detection (LOD) was calculated according to LOD = 3 N/S. Besides, the sensor showed good reproducibility and stability, which present provided new method for early and highly sensitive detection for plant viruses.

Electrochemical Sensors and Biosensors for Identification of Viruses: A Critical Review

Due to their life cycle, viruses can disrupt the metabolism of their hosts, causing diseases. If we want to disrupt their life cycle, it is necessary to identify their presence. For this purpose, it is possible to use several molecular-biological and bioanalytical methods. The reference selection was performed based on electronic databases (2020-2023). This review focused on electrochemical methods with high sensitivity and selectivity (53% voltammetry/amperometry, 33% impedance, and 12% other methods) which showed their great potential for detecting various viruses. Moreover, the aforementioned electrochemical methods have considerable potential to be applicable for care-point use as they are portable due to their miniaturizability and fast speed analysis (minutes to hours), and are relatively easy to interpret. A total of 2011 articles were found, of which 86 original papers were subsequently evaluated (the majority of which are focused on human pathogens, whereas articles dealing with plant pathogens are in the minority). Thirty-two species of viruses were included in the evaluation. It was found that most of the examined research studies (77%) used nanotechnological modifications. Other ones performed immunological (52%) or genetic analyses (43%) for virus detection. 5% of the reports used peptides to increase the method's sensitivity. When evaluable, 65% of the research studies had LOD values in the order of ng or nM. The vast majority (79%) of the studies represent proof of concept and possibilities with low application potential and a high need of further research experimental work.

Catalytic Hairpin Assembly-Based Self-Ratiometric Gel Electrophoresis Detection Platform for Reliable Nucleic Acid Analysis

The development of gel electrophoresis-based biodetection assays for point-of-care analysis are highly demanding. In this work, we proposed a ratiometric gel electrophoresis-based biosensing platform by employing catalytic hairpin assembly (CHA) process functions as both the signal output and the signal amplification module. Two types of nucleic acids, DNA and miRNA, are chosen for demonstration. The proposed strategy indeed provides a new paradigm for the design of a portable detection platform and may hold great potential for sensitive diagnoses.

Advances in rapid point-of-care virus testing

Outbreaks of viral diseases seriously jeopardize people's health and cause huge economic losses. At the same time, virology provides a new perspective for biology, molecular biology and cancer research, and it is important to study the discovered viruses with potential applications. Therefore, the development of immediate and rapid viral detection methods for the prevention and treatment of viral diseases as well as the study of viruses has attracted extensive attention from scientists. With the continuous progress of science and technology, especially in the field of bioanalysis, a series of new detection techniques have been applied to the on-site rapid detection of viruses, which has become a powerful approach for human beings to fight against viruses. In this paper, the latest research progress of rapid point-of-care detection of viral nucleic acids, antigens and antibodies is presented. In addition, the advantages and disadvantages of these technologies are discussed from the perspective of practical application requirements. Finally, the problems and challenges faced by rapid viral detection methods and their development prospects are discussed.

Trends and challenges in electroanalytical biosensing methodologies for infectious viral diseases

Viral pandemic diseases have disruptive global consequences leading to millions of deaths and a severe impact on the global economy. Inadequate preventative protocols have led to an overwhelming demand for intensive care leading to uncontrollable burdens and even breakdown of healthcare sectors across many countries. The rapid detection of viral disease helps in the understanding of the relevant intricacies, helping to tackle infection with improved guidelines. Portable biosensor devices offer promising solutions by facilitating on-site detection of viral pathogens. This review summarizes the latest innovative strategies reported using electroanalytical methods for the screening of viral antigens. The structural components of viruses and their categories are presented followed by the various recognition elements and transduction techniques involved in biosensors. Core sections focus on biosensors reported for viral genomic detection(DNA and RNA) and antigenic capsid protein. Strategies for addressing the challenges of electroanalytical biosensing of viral components are also presented. The advantages, and disadvantages of biorecognition elements and nanozymes for the detection of viral disease are highlighted. Such technical insights will help researchers working in chemistry, and biochemistry as well as clinicians working in medical diagnostics.

Surface Functionalization with Polymer Brushes via Surface-Initiated Atom Transfer Radical Polymerization: Synthesis, Applications, and Current Challenges

Polymer brushes have received great attention in recent years due to their distinctive properties and wide range of applications. The synthesis of polymer brushes typically employs surface-initiated atom transfer radical polymerization (SI-ATRP) techniques. To realize the control of the polymerization process in different environments, various SI-ATRP techniques triggered by different stimuli have been developed. This review focuses on the latest developments in different stimuli-triggered SI-ATRP methods, such as electrochemically mediated, photoinduced, enzyme-assisted, mechanically controlled, and organocatalyzed ATRP. Additionally, SI-ATRP technology triggered by a combination of multiple stimuli sources is also discussed. Furthermore, the applications of polymer brushes in lubrication, biological applications, antifouling, and catalysis are also systematically summarized and discussed. Despite the advancements in the synthesis of various types of 1D, 2D, and 3D polymer brushes via controlled radical polymerization, contemporary challenges remain in the quest for more efficient and straightforward synthetic protocols that allow for precise control over the composition, structure, and functionality of polymer brushes. We anticipate the readers could promote the understanding of surface functionalization based on ATRP-mediated polymer brushes and envision future directions for their application in surface coating technologies.

Impact of nanotechnology on conventional and artificial intelligence-based biosensing strategies for the detection of viruses

Recent years have witnessed the emergence of several viruses and other pathogens. Some of these infectious diseases have spread globally, resulting in pandemics. Although biosensors of various types have been utilized for virus detection, their limited sensitivity remains an issue. Therefore, the development of better diagnostic tools that facilitate the more efficient detection of viruses and other pathogens has become important. Nanotechnology has been recognized as a powerful tool for the detection of viruses, and it is expected to change the landscape of virus detection and analysis. Recently, nanomaterials have gained enormous attention for their value in improving biosensor performance owing to their high surface-to-volume ratio and quantum size effects. This article reviews the impact of nanotechnology on the design, development, and performance of sensors for the detection of viruses. Special attention has been paid to nanoscale materials, various types of nanobiosensors, the internet of medical things, and artificial intelligence-based viral diagnostic techniques.

Plant Virus Sensor for the Rapid Detection of Bean Pod Mottle Virus Using Virus-Specific Nanocavities

This study presents a miniaturized sensor for rapid, selective, and sensitive detection of bean pod mottle virus (BPMV) in soybean plants. The sensor employs molecularly imprinted polymer technology to generate BPMV-specific nanocavities in porous polypyrrole. Leveraging the porous structure, high surface reactivity, and electron transfer properties of polypyrrole, the sensor achieves a sensitivity of 143 μA ng-1 mL cm-2, a concentration range of 0.01-100,000 ng/mL, a detection time of less than 2 min, and a detection limit of 41 pg/mL. These capabilities outperform those of conventional methods, such as enzyme-linked immunosorbent assays and reverse transcription polymerase chain reactions. The sensor possesses the ability to distinguish BPMV-infected soybean plants from noninfected ones while rapidly quantifying virus levels. Moreover, it can reveal the spatial distribution of virus concentration across distinct leaves, a capability not previously attained by cost-effective sensors for such detailed viral data within a plant. The BPMV-specific nanocavities can also be easily restored and reactivated for multiple uses through a simple wash with acetic acid. While MIP-based sensors for plant virus detection have been relatively understudied, our findings demonstrate their potential as portable, on-site diagnostic tools that avoid complex and time-consuming sample preparation procedures. This advancement addresses a critical need in plant virology, enhancing the detection and management of plant viral diseases.

Improvement of duplex-specific nuclease salt tolerance by fusing DNA-binding domain of DNase from an extremely halotolerant bacterium Thioalkalivibrio sp. K90mix

Salt tolerance is an important property of duplex-specific nuclease (DSN). DSN with high salt tolerance can be more widely used in genetic engineering, especially in the production of nucleic acid drugs. To improve the salt tolerance of DSN, we selected five DNA-binding domains from extremophilic organisms, which have been shown the ability to improve salt tolerance of DNA polymerases and nucleases. The experimental results demonstrated that the fusion protein TK-DSN produced by fusing a N-terminal DNA-binding domain, which comprised two HhH (helix-hairpin-helix) motifs domain from an extremely halotolerant bacterium Thioalkalivibrio sp. K90mix, has a significantly improved salt tolerance. TK-DSN can tolerate the concentration of NaCl up to 800 mM; in addition, the ability of digesting DNA was also enhanced during in vitro transcription and RNA purification. This strategy provides the method for the personalized customization of biological tool enzymes for different applications.

Dual-signal amplified electrochemical biosensor based on eATRP and PEI for early detection of lung cancer

Carcinoembryonic antigen (CEA), a lung cancer marker with high sensitivity and specificity, plays vital roles in the early diagnosis of lung cancer. In this paper, an electrochemical biosensor for highly sensitive detection of CEA was constructed, which based on dual signal amplification of electrically mediated atom transfer radical polymerization (eATRP) and polyethyleneimine (PEI) for the first time. Firstly, CEA was captured in a specific recognition manner with CEA aptamer 1 (Apt1), which self-assembled on the electrode via "Au-S" bond. After that, CEA aptamer 2-PEI (Apt2-PEI) was recognized by CEA to form an Apt-antigen-Apt sandwich structure. Next, multiple initiation sites were introduced for the eATRP reaction by the amide reaction. Finally, numerous electroactive monomers, ferrocene methacrylate (FMMA), were grafted onto the modified electrode by eATRP. Under the optimized conditions, there was a wide linear detection range of 10^-3 ∼ 10² ng·mL^-1, and the limit of detection (LOD) was 70.17 fg·mL^-1. Compared to other reported sensors, this electrochemical biosensor used a simpler and more environmentally friendly eATRP, and the use of PEI increased the electron transfer rate. Moreover, the biosensor showed superior analytical performance in the clinical serums and has great promise for early lung cancer diagnosis applications.