DNA Tile and Invading Stacking Primer-Assisted CRISPR-Cas12a Multiple Amplification System for Entropy-Driven Electrochemical Detection of MicroRNA with Tunable Sensitivity

Hydrophilic/hydrophobic modified microchip for detecting multiple gene doping candidates using CRISPR-Cas12a and RPA

With significant advancements in understanding gene functions and therapy, the potential misuse of gene technologies, particularly in the context of sports through gene doping (GD), has come to the forefront. This raises concerns regarding the need for point-of-care testing of various GD candidates to counter illicit practices in sports. However, current GD detection techniques, such as PCR, lack the portability required for on-site multiplexed detection. In this study, we introduce an integrated microfluidics-based chip for multiplexed gene doping detection, termed MGD-Chip. Through the strategic design of hydrophilic and hydrophobic channels, MGD-Chip enables the RPA and CRISPR-Cas12a assays to be sequentially performed on the device, ensuring minimal interference and cross-contamination. Six potential GD candidates were selected and successfully tested simultaneously on the platform within 1 h. Demonstrating exceptional specificity, the platform achieved a detection sensitivity of 0.1 nM for unamplified target plasmids and 1 aM for amplified ones. Validation using mouse models established by injecting IGFI and EPO transgenes confirmed the platform's efficacy in detecting gene doping in real samples. This technology, capable of detecting multiple targets using portable elements, holds promise for real-time GD detection at sports events, offering a rapid, highly sensitive, and user-friendly solution to uphold the integrity of sports competitions.

Antibody-Protein-Aptamer Electrochemical Biosensor based on Highly Efficient Proximity-Induced DNA Hybridization on Tetrahedral DNA Nanostructure for Sensitive Detection of Insulin-like Growth Factor-1

Herein, an antibody-protein-aptamer electrochemical biosensor was designed by highly efficient proximity-induced DNA hybridization on a tetrahedral DNA nanostructure (TDN) for ultrasensitive detection of human insulin-like growth factor-1 (IGF-1). Impressively, the IGF-1 antibody immobilized on the top vertex of the TDN could effectively capture the target protein with less steric effect, and the ferrocene-labeled signal probe (SP) bound on the bottom vertex of the TDN was close to the electrode surface for generating a strong initial signal. In the presence of target protein IGF-1 and an aptamer strand, an antibody-protein-aptamer sandwich could be formed on the top vertex of TDN, which would trigger proximity-induced DNA hybridization to release the SP on the bottom vertex of TDN; therefore, the signal response would decrease dramatically, enhancing the sensitivity of the biosensor. As a result, the linear range of the proposed biosensor for target IGF-1 was 1 fM to 1 nM with the limit of detection down to 0.47 fM, which was much lower than that of the traditional TDN designs on electrochemical biosensors. Surprisingly, the use of this approach offered an innovative approach for the sensitive detection of biomarkers and illness diagnosis.

Multiplex Assay of Cytokines with Tunable Detection Ranges for the Precise Diagnosis of Breast Cancer

Precise profiling of the cytokine panel consisting of different levels of cytokines can provide personalized information about several diseases at certain stages. In this study, we have designed and fabricated an "all-in-one" diagnostic tool kit to bioassay multiple inflammatory cytokines ranging from picograms per milliliter to μg/mL in a small cytokine panel. Taking advantage of the kit fabricated by the DNA-encoded assembly of nanocatalysts in dynamic regulation and signal amplification, we have demonstrated the multiplex, visual, and quantitative detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) with limits of detection of 1.6 ng/mL (61.54 pM), 20 pg/mL (1.57 pM), and 4 pg/mL (0.19 pM), respectively. This diagnostic tool kit can work well with commercial kits for detecting serum cytokines from breast cancer patients treated with immunotherapies. Furthermore, a small cytokine panel composed of CRP, PCT, and IL-6 is revealed to be significantly heterogeneous in each patient and highly dynamic for different treatment courses, showing promise as a panel of quantitative biomarker candidates for individual treatments. So, our work may provide a versatile diagnostic tool kit for the visual detection of clinical biomarkers with an adjustable broad detection range.

Protonation-mediated DNA tile self-assembly with nuclease resistance characteristic for signal-amplified detection of microRNAs

DNA nanotechnology, developing rapidly in recent years, has unprecedented superiorities in biological application-oriented research including high programmability, convenient functionalization, reconfigurable structure, and intrinsic biocompatibility. However, the susceptibility to nucleases in the physiological environment has been an obstacle to applying DNA nanostructures in biological science research. In this study, a new DNA self-assembly strategy, mediated by double-protonated small molecules instead of classical metal ions, is developed to enhance the nuclease resistance of DNA nanostructures while retaining their integrality and functionality, and the relative application has been launched in the detection of microRNAs (miRNAs). Faced with low-abundance miRNAs, we integrate hybrid chain reaction (HCR) with DNA self-assembly in the presence of double-protonated small molecules to construct a chemiluminescence detection platform with nuclease resistance, which utilizes the significant difference of molecular weight between DNA arrays and false-positive products to effectively separate of reaction products and remove the detection background. This strategy attaches importance to the nucleic acid stability during the assay process via improving nuclease resistance while rendering the detection results for miRNAs more authentic and reliable, opening our eyes to more possibilities for the multiple applications of customized DNA nanostructures in biology, including bioassay, bioimaging, drug delivery, and cell modulation.

Photocontrollable DNA Walker-Based Molecular Circuit for the Tunable Detection of MicroRNA-21 Using Metal-Organic Frameworks as Label-Free Fluorescence Tags

Tunable detection of microRNA is crucial to meet the desired demand for sample species with varying concentrations in clinical settings. Herein, we present a DNA walker-based molecular circuit for the detection of miRNA-21 (miR-21) with tunable dynamic ranges and sensitivity levels ranging from fM to pM. The phosphate-activated fluorescence of UiO-66-NH2 metal-organic framework nanoparticles was used as label-free fluorescence tags due to their competitive coordination effect with the Zr atom, which significantly inhibited the ligand-to-metal charge transfer. To achieve a tunable detection performance for miR-21, the ultraviolet sensitive o-nitrobenzyl was induced as a photocleavable linker, which was inserted at various sites between the loop and the stem of the hairpin probe to regulate the DNA strand displacement reaction. The dynamic range can be precisely regulated from 700- to 67,000-fold with tunable limits of detection ranging from 2.5 fM to 36.7 pM. Impressively, a Boolean logic tree and complex molecular circuit were constructed for logic computation and cancer diagnosis in clinical blood samples. This intelligent biosensing method presents a powerful solution for converting complex biosensing systems into actionable healthcare decisions and will facilitate early disease diagnosis.