Single-excited double-emission CdTe@CdS quantum dots for use in a fluorometric hybridization assay for multiple tumor-related microRNAs

Gold nanoparticle-mediated fluorescence resonance energy transfer for analytical applications in the fields of life health and safety

Fluorescence Resonance Energy Transfer (FRET) has emerged as a predominant, highly sensitive, and homogeneous optical analytical technique in the realm of analytical testing and bio-imaging. Gold nanoparticles (AuNPs) demonstrate a size-dependent, broader absorption range within visible wavelengths owing to the phenomenon of surface plasmon resonance. As a result, they can effectively act as light acceptors, enabling the creation of a donor-acceptor system crucial for achieving precise target analyte analysis. In this comprehensive review, we present an extensive survey of recent research advancements in the field of FRET techniques based on AuNPs for the analytical detection of a wide range of entities, including some biomolecules, pesticides, enzymes, microorganisms, food safety and environmental pollutants. Additionally, we elucidate the procedural strategies and underlying mechanisms involved. Finally, we provide perspectives on the current issues and future efforts surrounding the FRET applications of AuNPs in biological analysis. Overall, this review aims to provide a holistic comprehension of gold nanoparticle applications in life analysis using FRET, while also presenting a promising vision for future endeavors in this domain.

Signal differentiation models for multiple microRNA detection: a critical review

MicroRNAs (miRNAs) are a class of small, single-stranded non-coding RNAs which have critical functions in various biological processes. Increasing evidence suggested that abnormal miRNA expression was closely related to many human diseases, and they are projected to be very promising biomarkers for non-invasive diagnosis. Multiplex detection of aberrant miRNAs has great advantages including improved detection efficiency and enhanced diagnostic precision. Traditional miRNA detection methods do not meet the requirements of high sensitivity or multiplexing. Some new techniques have opened novel paths to solve analytical challenges of multiple miRNA detection. Herein, we give a critical overview of the current multiplex strategies for the simultaneous detection of miRNAs from the perspective of two different signal differentiation models, including label differentiation and space differentiation. Meanwhile, recent advances of signal amplification strategies integrated into multiplex miRNA methods are also discussed. We hope this review provides the reader with future perspectives on multiplex miRNA strategies in biochemical research and clinical diagnostics.

DNA functionalized double quantum dots-based fluorescence biosensor for one-step simultaneous detection of multiple microRNAs

The disease diagnosis by detecting single microRNAs (miRNAs) can produce high false positive rate. Herein, a novel fluorescence biosensor method for one-step simultaneous detection of multiple miRNAs was proposed by using single-stranded DNA (ssDNA) functionalized double quantum dots (QDs) and black hole quencher (BHQ)-decorated magnetic nanobeads (MNs). MNs were linked with two black hole quenchers (BHQ1 and BHQ3) via a complementary DNA (cDNA). The ssDNA/cDNA hybridization contributed to the fluorescence quenching of double QDs due to the fluorescence resonance energy transfer (FRET) between double QDs and BHQ. In the presence of target miRNA-33 (miR-33) and miRNA-125b (miR-125b), the ssDNA₁ and ssDNA₂ were respectively hybridized with miR-33 and miR-125b to form more stable duplexes. Thus, the double QDs were released into supernatant after the magnetic separation, leading to the fluorescence signals recovery at 537 nm and 647 nm. A wide linear range (0.5 nM-320 nM for miR-33 and 0.1 nM-250 nM for miR-125b) and low limits of detection (0.09 nM for miR-33 and 0.02 nM for miR-125b) were achieved. Moreover, our approach has been demonstrated to simultaneously detect miR-33 and miR-125b in cell extracts. With advantages of high sensitivity, strong specificity, low background and low cost, the strategies show great potentials for the detection of various targets in bioanalysis and disease diagnosis.