No abstract

A facile “dots-in-zeolites” strategy is developed to synthesize a new class of CD-based TADF materials with ultralong lifetimes.

Swimming biohybrid microsized robots (e.g., bacteria- or sperm-driven microrobots) with self-propelling and navigating capabilities have become an exciting field of research, thanks to their controllable locomotion in hard-to-reach areas of the body for noninvasive drug delivery and treatment. However, current cell-based microrobots are susceptible to immune attack and clearance upon entering the body. Here, we report a neutrophil-based microrobot (“neutrobot”) that can actively deliver cargo to malignant glioma in vivo. The neutrobots are constructed through the phagocytosis of Escherichia coli membrane-enveloped, drug-loaded magnetic nanogels by natural neutrophils, where the E. coli membrane camouflaging enhances the efficiency of phagocytosis and also prevents drug leakage inside the neutrophils. With controllable intravascular movement upon exposure to a rotating magnetic field, the neutrobots could autonomously aggregate in the brain and subsequently cross the blood-brain barrier through the positive chemotactic motion of neutrobots along the gradient of inflammatory factors. The use of such dual-responsive neutrobots for targeted drug delivery substantially inhibits the proliferation of tumor cells compared with traditional drug injection. Inheriting the biological characteristics and functions of natural neutrophils that current artificial microrobots cannot match, the neutrobots developed in this study provide a promising pathway to precision biomedicine in the future.

Luminescence anti‐counterfeiting derives from the easily changeable luminescence behaviors of luminescence materials under the regulation of various external stimuli (such as excitation light, chemical reagent, heat, and mechanical force, etc.) and luminescence lifetime, which plays an important role in preventing forgery of currency, artworks, and product brands. According to the numbers of changes of anti‐counterfeiting labels under various regulation conditions, luminescence anti‐counterfeiting can be classified into three levels from elementary to advanced: single‐level anti‐counterfeiting, double‐level anti‐counterfeiting, and multilevel anti‐counterfeiting. In this review, the recent achievements in luminescence anti‐counterfeiting are summarized, and the regulation of various factors to anti‐counterfeiting labels is discussed. Finally, existing problems, future challenges, and possible development directions are proposed in order to realize facile, quick, low‐cost, environmentally friendly, and difficult‐to‐replicate advanced luminescence anti‐counterfeiting.

Engineering self-propelled micromotors with good biocompatibility and biodegradability for actively seeking disease sites and targeted drug transport remains a huge challenge. In this study, neutrophils with intrinsic chemotaxis capability were transformed into self-guided hybrid micromotors by integrating mesoporous silica nanoparticles (MSNs) with high loading capability. To ensure the compatibility of neutrophil cells with drug-loaded MSNs, bacteria membranes derived from E. coli were coated on MSNs in advance by a camouflaging strategy. The resulting biohybrid micromotors inherited the characteristic chemotaxis capability of native neutrophils and could effectively move along the chemoattractant gradients produced by E. coli. Our studies suggest that this camouflaging approach, which favors the uptake of MSNs into neutrophils without loss of cellular activity and motility, could be used to construct synthetic nanoparticle-loaded biohybrid micromotors for advanced biomedical applications.

As a new class of luminescent nanomaterials, carbon dots (CDs) have aroused significant interest because of their fascinating photoluminescence properties and potential applications in biological, optoelectronic, and energy‐related fields. Strikingly, embedding CDs in host matrices endow them with intriguing luminescent properties, in particular, room temperature phosphorescence and thermally activated delayed fluorescence, due to the confinement effect of the host matrix and the H‐bonding interactions between CDs and the matrix. Here, the state‐of‐the‐art strategies for introducing CDs in various host matrices are summarized, such as nanoporous materials, polyvinyl alcohol, polyurethane, potash alum, layered double hydroxides, amorphous silica, etc. The resultant luminescent properties of the composites and their emission mechanisms are discussed. Their applications in bioimaging, drug delivery/release, sensing, and anticounterfeiting are also presented. Finally, current problems and challenges of CDs‐based composites are noted for future development of such luminescent materials.

Carbon dots (CDs) with red-emitting room-temperature phosphorescence (RTP) are rarely reported because of the increasing nonradiative decay of the excited states and the decreasing energy gap between the excited states and ground states. Herein, we demonstrate a facile strategy for modulating the RTP properties of CDs in terms of donor–acceptor energy transfer (EnT) in the CDs-in-zeolite system. Upon tuning of the heteroatoms (Zn 2+ , Mn 2+ ) doped in the aluminophosphate zeolite frameworks, CDs@zeolite composites with green and red phosphorescence have been prepared via in situ hydrothermal synthesis. In such composites, the zeolite matrix provides an efficient confinement role in stabilizing the triplet states of CDs. Significantly, the Mn-doped zeolite could act as an energy acceptor allowing EnT from excitons of CDs to the dopant in the host matrix, generating the intriguing red RTP behavior. This work provides an effective strategy for developing CD-based composite materials with special RTP emissions as well as new fields for applications.

High‐efficiency red room‐temperature phosphorescence (RTP) emissions have been achieved by embedding carbon dots (CDs) in crystalline Mn‐containing open‐framework matrices. The rationale of this strategy relies on two factors: 1) the carbon source, which affects the triplet energy levels of the resulting CDs and thus the spectral overlap and 2) the coordination geometry of the Mn atoms in the crystalline frameworks, which determines the crystal‐field splitting and thus the emission spectra. Embedding the carbon dots into a matrix with 6‐coordinate Mn centers resulted in a strong red RTP with a phosphorescence efficiency of up to 9.6 %, which is higher than that of most reported red RTP materials. The composite material has an ultrahigh optical stability in the presence of strong oxidants, various organic solvents, and strong ultraviolet radiation. A green‐yellow RTP composite was also prepared by using a matrix with 4‐coordinate Mn centers and different carbon precursors.