Visualization of Long Noncoding RNA MEG3 in Living Cells by a Triple-Helix-Powered 3D Catcher

Deciphering the Temporal-Spatial Interactive Heterogeneity of Long Non-Coding RNAs and RNA-Binding Proteins in Living Cells at Single-Cell Resolution

The investigation of long noncoding RNAs (lncRNAs) and RNA binding proteins (RBPs) interactions in living cell holds great significance for elucidating their critical roles in a variety of biological activities, but limited techniques are available to profile the temporal-spatial dynamic heterogeneity. Here, we introduced a molecular beacon-functionalized nanoneedle array designed for spatially resolved profiling of lncRNA-RBP interactions (Nano-SpatiaLR). A nanoneedle array modified with a molecular beacon is employed to selectively isolate specific intracellular lncRNAs and their associated RBPs without affecting cell viability. The RBPs are then in situ analyzed with a fluorescent labeled antibody and colocalized with lncRNA signals to get a quantitative measurement of their dynamic interactions. Additionally, leveraging the spatial distribution and nanoscale modality of the nanoneedle array, this technique provides the spatial heterogeneity information on cellular lncRNA-RBPs interaction at single cell resolution. In this study, we tracked the temporal-spatial interactive heterogeneity dynamics of lncRNA-RBPs interaction within living cells across different biological progresses. Our findings demonstrated that the interactions between lncRNA HOTAIR and RBPs EZH2 and LSD1 undergo significant changes in response to drug treatments, particularly in tumor cells. Moreover, these interactions become more intensified as tumor cells aggregate during the proliferation process.

Dual amplified ratiometric fluorescence ELISA based on G-quadruplex/hemin DNAzyme using tetrahedral DNA nanostructure as scaffold for ultrasensitive detection of dibutyl phthalate in aquatic system

Dibutyl phthalate (DBP) is considered as one of the most widely used phthalate esters (PAEs), which has attracted worldwide concerns because of its potential threats to eco-environments and human health. Systematic investigations of DBP environmental occurrence contribute to the further risk assessment, which depends on effective and available analytical methods. In this study, an amplified ratiometric fluorescence ELISA was established for sensitive and high-throughput detection of DBP in the aquatic system based on a novel tetrahedral DNA nanostructure (TDN)-scaffolded-DNAzyme (Tetrazyme). Wherein, Tetrazyme was prepared by the precise folding of G-quadruplex sequence on three vertex angles of the TDN, together with hemin as the horseradish peroxidase (HRP)-mimicking enzyme. The rigid TDN avoided the local overcrowding effect to provide a reasonable spatial spacing on the interface for G-quadruplex sequence, increasing the collision chance between DNAzyme and substrates, improving the catalytic ability of DNAzyme effectively. Besides, streptavidin (SA) and biotin (bio) were used to anchor TDN and antibody, in which the specific binding of SA/bio could make more Tetrazyme conjugate on each signal element, resulting in the dual signal amplification. Meanwhile, the accuracy and precision were enhanced owing to the inherent built-in rectification to the environment from the dual output ratiometric fluorescence assay. Under the optimized conditions, the detection limit of this proposed method was 0.17 ng/mL (16 times lower than that of conventional ELISA using the same antibody) with a satisfactory accuracy (recoveries, 79.0%- 116.2%; CV, 2.1-6.5%). Overall, this platform provides a promising way for accurate, sensitive and rapid determination of DBP from environmental waters.