Real-Time Fluorescence In Situ Visualization of Latent Fingerprints Exceeding Level 3 Details Based on Aggregation-Induced Emission.

A water-soluble probe, TPA-1OH, with aggregation-induced emission activity is synthesized and used for expedient real-time fluorescence in situ visualization of latent fingerprints (LFPs). A TPA-1OH aqueous solution exhibits nonfluorescence in pure water while strong fluorescence upon molecular aggregation induced by addition of poor solvent. Fluorescence images of LFPs on a variety of substrates, including rough surfaces such as walls, bricks, and paper, are developed under 405 nm light, by soaking in or spraying with a TPA-1OH aqueous solution (30 µM) without any necessity of organic cosolvents and post-treatment steps. The probe is noncytotoxic at a concentration lower than 50 µM. The development process of LFPs is demonstrated by real-time fluorescence in situ imaging. The exponential relationship between the relative fluorescence intensity and time is deduced from the fitting curve. The LFP images developed by TPA-1OH are evident and intact enough to allow that the level 1-3 details are displayed and analyzed. Noteworthily, the level 3 details of LFPs such as the fingerprint ridge width and the characteristics of the sweat pores are evidently visible under fluorescence microscopy. Even the nanoscopic details exceeding level 3 are visualized under super-resolution microscopy with sub-50 nm optical resolution.

AIE-Based Dynamic in Situ Nanoscale Visualization of Amyloid Fibrillation from Hen Egg White Lysozyme.

Protein misfolding and denaturation, represented by amyloid fibrillation, are associated with many diseases. However, as a general chemical biological process, the dynamic structure information on amyloid fibrillation has not been demonstrated categorically. Herein, hen egg white lysozyme (HEWL) was used as the model protein of interest to realize in situ nanoscale imaging of protein fibrillation process using the fluorophores with aggregation-induced emission (AIE) activity. The AIE-active fluorophores exhibit the reversible capability of association and dissociation with ß-sheet structure and thus dynamic binding-induced emission, which causes the spontaneous switching of fluorescence. The entire HEWL denaturation process induced by sodium dodecyl sulfate (SDS) at ambient conditions was demonstrated in detail by using two AIE-active fluorophores (TPE-NaSO3 and PD-BZ-OH) through reversible electrostatic interaction and specific labeling between AIE probes and ß-sheet structures of amyloid fibrils, respectively. The results indicate that PD-BZ-OH is more specific AIE probe for amyloid fibrils than TPE-NaSO3. In comparison, the SEM and TEM results show the same denaturation process of protein fibrillation induced by SDS at different concentrations. The static super-resolution imaging of amyloid fibrils is performed with a resolution of 35 nm using PD-BZ-OH aqueous solution without additional auxiliary conditions. The dynamic evolution process of HEWL amyloid fibrillation is in situ visualized through super-resolution fluorescent microscopy with nanoscale resolution. Both static and dynamic super-resolution imaging of amyloid fibrillation provides detailed nanoscale structure information exceeding 50 nm resolution, which is of great significance in the exploration of amyloid fibrillation and related diseases.

Graphene-like MoS2 Nanosheets on Carbon Fabrics as High-Performance Binder-free Electrodes for Supercapacitors and Li-Ion Batteries.

Two-dimensional layer-structure materials are now of great interest in energy storage devices, owing to their graphene-like structure and high theoretical capacity. Herein, graphene-like molybdenum disulfide (MoS2) nanosheets were uniformly grown on carbon fabrics by using a hydrothermal method. They were evaluated as binder-free electrodes for Li-ion batteries (LIBs) and supercapacitors. As expected, long cycling life and high capacity/capacitance are achieved. When used as self-standing electrodes for LIBs, they deliver a high area capacity of ∼0.5 mAh/cm2 even after 400 cycles and remarkable rate capability in the charge/discharge potential range of 1-3 V. In addition, a three-dimensional integrated electrode of the MoS2 nanosheet exhibits a high capacitance of 103.5 mF/cm2 and long cycling stability up to at least 15 000 cycles at a current density of 3 mA/cm2 for supercapacitors. The great cycling stability of MoS2 in supercapacitors is promising in the enhancement of cycling stability through their integration with other materials as alternatives to graphene in some special fields.