Intermolecular hydrogen-bond interaction to promote thermoreversible 2'-deoxyuridine-based AIE-organogels

Fluorescent supramolecular nucleoside-based organogels or hydrogels have attracted increasing attention owing to their tunable stability,drug delivery,tissue engineering,and inherent biocompatibility for applications in designing sensors.As the temperature of a constant TPE-Octa-dU gelato r at MGC as low as 0.2 wt%was increased with gel to sol transition,a progressive decrease in the fluorescence intensity was observed.~1 H NMR study in ethanol-d_(6)/H_(2)O revealed the existence of intermolecular hydrogen-bond interaction between uridine nucleobase and triazole moieties.Based on these experiments,thus organogels induced by hydrogen bonding can promote an aggregation-induced emission(AIE)of TPE moiety.Thermoreversible gelation properties have been investigated systematically,including AIE-shapemorphing architecture owing to their unique solid-liquid interface and easy processability.At the same line,the related TPE-EdU derivative which was synthesized from 5-ethynyl-2'-deoxyuridine does not delive r organogels or hydrogels,a nd under similar circumstances TPE moiety of TPE-EdU does not efficiently exhibit AIE phenomenon either.

Biocompatible and non cytotoxic nucleoside-based AIEgens sensor for lighting-up nucleic acids

Aggregation-induced emission luminogens(AIEgens) have been used in biomacromolecules detection.Herein,TPE-dC and TPE-dU acted as the nucleoside-based AIEgens sensors in the first case,which can be used to detect ctDNA and rRNA in vitro and light up the nucleus in vivo depending on the intermolecular binding affinity.This AIE process enables the quantitative analysis or visualization of nucleic acids in solution or gels state,respectively.Furthermore,confocal laser scanning microscopy(CLSM) images of L929 cells stained with TPE-dC or TPE-dU clearly shows that nucleoside-based AIEgens bio-probes can pass the cell membranes to reach the cell nucleus,without cytotoxicity at the imaging condition(incubation time> 12 h,and 10 μmol/L of concentration).Since the nucleus is rich in DNA/RNA,fluorescence turn-on mode has a great potential in nucleus imaging and clinical diagnosis.

An excimer ‘ON–OFF’ switch based on telomeric G-quadruplex and rGO for trace thrombin detection

In the recent decade,GO has emerged as an amazing 2D nanomaterial for developing DNA-based biosensors due to its fluorescence quenching properties,whereas similar research based on rGO was reported rarely.Herein,a novel multi-pyrene functionalized G-rich DNA probe based on the screened rGO showed much higher fluorescence quenching efficiency and excimer emission than that of universal GO.Different from the universal thrombin detection of the G4-forming aptamer-TBA(GGTTGGTGTGGTTGG),the original telomeric sequence is used in this study.The excimer emission“ON-OFF”switch amplified the response of thrombin detection is as low as 50 units.Furthermore,for four pyrene moieties that are sited in a crowded steric circumstance,the melting temperature(T_(m))values and molecular dynamics simulations showed a positive effect on duplex G-quadruplex or _(G)DNA·_(c)DNA stability,without disturbing its helix structure.