Self-Assembly-Induced Far-Red/Near-Infrared Fluorescence Light-Up for Detecting and Visualizing Specific Protein–Peptide Interactions

Abstract

Understanding specific protein-peptide interactions could offer a deep insight into the development of therapeutics for many human diseases. In this work, we designed and synthesized a far-red/near-infrared (FR/NIR) fluorescence light-up probe (DBT-2EEGWRESAI) by simply integrating two tax-interacting protein-1 (TIP-1)-specific peptide ligands (EEGWRESAI) with one 4,7-di(thiophen-2-yl)-2,1,3-benzothiadiazole (DBT) unit. We first demonstrated that DBT is an environment-sensitive fluorophore with FR/NIR fluorescence due to its strong charge transfer character in the excited state. Thanks to the environmental sensitivity of DBT, the probe DBT-2EEGWRESAI is very weakly fluorescent in aqueous solution but lights up its fluorescence when the probe specifically binds to TIP-1 protein or polyprotein (ULD-TIP-1 tetramer). It is found that the DBT-2EEGWRESAI/TIP-1 protein and the DBT-2EEGWRESAI/ULD-TIP-1 tetramer could self-assemble into spherical nanocomplexes and a nanofiber network, respectively, which lead to probe fluorescence turn-on through providing DBT with a hydrophobic microenvironment. By virtue of the self-assembly-induced FR/NIR fluorescence turn-on, DBT-2EEGWRESAI can detect and visualize specific protein/polyprotein-peptide interactions in both solution and live bacteria in a high contrast and selective manner.

Folic acid-targeted disulfide-based cross-linking micelle for enhanced drug encapsulation stability and site-specific drug delivery against tumors

“…The particle sizes of them were ∼100 nm, which could enable these spherical vehicles to target tumor tissues via enhanced permeability and retention effect. 5,6 The Cur release profiles from NCM and CCM are shown in Figure 6A and 6B, less Cur was released from CCM than from NCM at pH 7.4, which proved higher loading stability after being cross-linked by disulfide bond. These results may contribute to the reduced drug leakage from CCM during sample storage and blood circulation in vivo.…”

“…After being entrapped by various nanosized vehicles, [1][2][3][4] the circulation time of therapeutic agents was prolonged, and the concentration of drugs accumulated into tumor sites was enhanced owing to the enhanced permeability and retention effect. 5,6 However, the nanocarrier for this drug delivery system is still confronted with a series of barriers when applied to antitumor activities in vitro and in vivo. [7][8][9] Among them, encapsulation stability is an urgent problem to be solved.…”

Supramolecular biofunctional materials

“…The self-assembly-induced FR/NIR fluorescence turn-on made DBT-2EEGWRESAI an excellent probe for detecting and visualizing specific protein/polyprotein-peptide interactions in both cell-free solutions and in live bacteria. [324]…”

AIEgen-based theranostic system: targeted imaging of cancer cells and adjuvant amplification of antitumor efficacy of paclitaxel

“…2 Among diverse imaging techniques, fluorescence imaging is an excellent alternative due to the advantages of superb sensitivity, manoeuvrable instruments, low cost and reliable safety. 3 Furthermore, a considerable number of fluorescence imaging agents are perfectly suitable for theranostic application, as they can undergo photophysical and photochemical processes under light irradiation to generate toxic reactive oxygen species (ROS) in situ . 4 However, traditional fluorescent materials often suffer from numerous disadvantages that greatly limit their practical application in theranostics.…”