Facile Preparation of Fluorescent Nanoparticles with Tunable Exciplex Emission and Their Application to Targeted Cellular Imaging

Controlling the Interaction between Fluorescent Gold Nanoclusters and Biointerfaces for Rapid Discrimination of Fungal Pathogens

Nondestructive detection and discrimination of fungal pathogens is essential for rapid and precise treatment, which further effectively prevents antifungal resistance from overused drugs. In this work, fluorescent gold nanoclusters served as the basis for discriminating Candida species. Varied on surface ligands, these gold nanoclusters demonstrated different optical properties as a result of the perturbation effects of ligands. The biointerface interaction between the surface ligands of gold nanoclusters and the cell walls of Candida species can be constructed, and their restriction on ligands perturbation effect produced enhanced fluorescence signals. Owing to the variation of the cell wall composition, cells of different Candida species demonstrated different degrees of association with the gold nanoclusters, leading to discriminable amounts of fluorescence enhancements. The reverse signal response from these gold nanoclusters gives rise to a synergistic and effective assay that allows identification of Candida species.

Different Surface Interactions between Fluorescent Conjugated Polymers and Biological Targets

Fluorescent conjugated polymers (CPs) have attracted considerable interest in biosensing owing to their high fluorescence, tunable bandgap, and good biocompatibility. Aiming at acquiring the desired optical responses of CPs for bioapplications, it is essential that the CPs bind to biological targets with high efficacy and affinity. However, the efficient binding of CPs is largely driven by their effective interaction with target surfaces. In this Review, we will focus on the different surface interactions that pervade between CPs and biological targets. The multiple surface interactions can lead to changes in spatial conformation and distribution of CPs, which manifest alterable optical properties of CPs based on accumulation of target-directed CPs, Förster resonance energy transfer mechanism, and metal-enhanced fluorescence mechanism. Then, we display diverse bioapplications applying CPs-based surface interactions, such as cell imaging, imaging-guided detection, and photodynamic therapy. Finally, the challenges and future developments to control the efficient attachment of CPs to biological targets are discussed. We expect that the understanding of surface interactions between CPs and biological targets benefits the CPs-based system design and expands their applications in biological detections and therapies.

Thermally activated delayed fluorescence exciplex emitters for high-performance organic light-emitting diodes

Owing to their natural thermally activated delayed fluorescence (TADF) characteristics, the development of exciplex emitters for organic light-emitting diodes (OLEDs) has witnessed booming progress in recent years. Formed between electron-donating and electron-accepting molecules, exciplexes with intermolecular charge transfer processes have unique advantages compared with unimolecular TADF materials, offering a new way to develop high-performance TADF emitters. In this review, a comprehensive overview of TADF exciplex emitters is presented with a focus on the relationship between the constituents of exciplexes and their electroluminescence performance. We summarize and discuss the latest and most significant developments of TADF exciplex emitters. Notably, the design principles of efficient TADF exciplex emitters are systematically categorized into three systems within this review. These progressive achievements of TADF exciplex emitters point out future challenges to trigger more research endeavors in this growing field.

Gold Nanocluster-Decorated Nanocomposites with Enhanced Emission and Reactive Oxygen Species Generation

Ligand-protected gold nanoclusters (AuNCs) show promise for high performance in biological applications, such as imaging and therapeutics. The assembly of AuNCs with biological macromolecules represents a simple but effective approach to fine-tuning of material functionalities. Thus, these materials might enable intracellular applications of AuNCs. Herein, we prepared a new AuNC-based nanometric system through a self-assembly approach mediated by hydrophobic and electrostatic effects. We show that hydrophobic and electrostatic effects between fluorescent AuNCs with protamine and hyaluronic acid contribute to the formation of small nanocomposites with acceptable colloidal stability. More importantly, the AuNC-decorated nanocomposites show assembly enhanced emission and singlet oxygen generation. In vitro experiments showed that our nanocomposites labeled specific cells by targeting CD44 and induced cell death by producing singlet oxygen. Hence, our AuNC-decorated nanocomposites show great potential as theranostic fluorescent nanomaterials.