Magnetic microrobots and nanorobots can be remotely controlled to propel in complex biological fluids with high precision by using magnetic fields. Their potential for controlled navigation in hard-to-reach cavities of the human body makes them promising miniaturized robotic tools to diagnose and treat diseases in a minimally invasive manner. However, critical issues, such as motion tracking, biocompatibility, biodegradation, and diagnostic/ therapeutic effects, need to be resolved to allow preclinical in vivo development and clinical trials. We report biohybrid magnetic robots endowed with multifunctional capabilities by integrating desired structural and functional attributes from a biological matrix and an engineered coating. Helical microswimmers were fabricated from Spirulina microalgae via a facile dip-coating process in magnetite (Fe 3 O 4) suspensions, superparamagnetic, and equipped with robust navigation capability in various biofluids. The innate properties of the microalgae allowed in vivo fluorescence imaging and remote diagnostic sensing without the need for any surface modification. Furthermore, in vivo magnetic resonance imaging tracked a swarm of microswimmers inside rodent stomachs, a deep organ where fluorescence-based imaging ceased to work because of its penetration limitation. Meanwhile, the microswimmers were able to degrade and exhibited selective cytotoxicity to cancer cell lines, subject to the thickness of the Fe 3 O 4 coating, which could be tailored via the dip-coating process. The biohybrid microrobots reported herein represent a microrobotic platform that could be further developed for in vivo imaging-guided therapy and a proof of concept for the engineering of multifunctional microrobotic and nanorobotic devices.

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Bacteria‐inspired magnetic helical micro‐/nanoswimmers can be actuated and steered in a fuel‐free manner using a low‐strength rotating magnetic field, generating remotely controlled 3D locomotion with high precision in a variety of biofluidic environments. They are therefore envisioned for biomedical applications related to targeted diagnosis and therapy. In this article, a porous hollow microswimmer possessing an outer shell aggregated by mesoporous spindle‐like magnetite nanoparticles (NPs) and a helical‐shaped inner cavity is proposed. The fabrication is straightforward via a cost‐effective mass‐production process of biotemplated synthesis using helical microorganisms. Here, Spirulina‐based fabrication is demonstrated as an example. The fabricated microswimmers are superparamagnetic and exhibit low cytotoxicity. They are also capable of performing structural disassembly to form individual NPs using ultrasound when needed. For the first time in the literature of helical microswimmers, a porous hollow architecture is successfully constructed, achieving an ultrahigh specific surface area for surface functionalization and enabling diffusion‐based cargo loading/release. Furthermore, experimental and analytical results indicate better swimming performance of the microswimmers than the existing non‐hollow helical micromachines of comparable sizes and dimensions. These characteristics of the as‐proposed microswimmers suggest a novel microrobotic tool with high loading capacity for targeted delivery of therapeutic/imaging agents in vitro and in vivo.

Two-dimensional (2D) lead halide perovskites with distinct excitonic feature have shown exciting potential for optoelectronic applications. Compared to their three-dimensional counterparts with large polaron character, how the interplay between long- and short- range exciton-phonon interaction due to polar and soft lattice define the excitons in 2D perovskites is yet to be revealed. Here, we seek to understand the nature of excitons in 2D CsPbBr3 perovskites by static and time-resolved spectroscopy which is further rationalized with Urbach-Martienssen rule. We show quantitatively an intermediate exciton-phonon coupling in 2D CsPbBr3 where exciton polarons are momentarily self-trapped by lattice vibrations. The 0.25 ps ultrafast interconversion between free and self-trapped exciton polaron with a barrier of ~ 34 meV gives rise to intrinsic asymmetric photoluminescence with a low energy tail at room temperature. This study reveals a complex and dynamic picture of exciton polarons in 2D perovskites and emphasizes the importance to regulate exciton-phonon coupling.

Chemical systems with external control capability and selfrecoverability are promising since they can avoid additional chemical or energy imposition during the working process. However, it remains challenging to employ such a nonequilibrium method for the engineering of optoelectronic function and for visualization. Here, we report a functional molecule that can undergo intense conformational regulation upon photoexcitation. It enables a dynamical change in hydrophobicity and a follow-up molecular aggregation in aqueous media, accordingly leading to an aggregation-induced phosphorescence (AIP) behavior. This successive performance is self-recoverable, allowing a rapid (second-scale cycle) and long-standing (>10 3 cycles) flicker ability under rhythmical control of the AIP. Compared with traditional bidirectional manipulations, such monodirectional photocontrol with spontaneous reset profoundly enhances the operability while mostly avoiding possible side reactions and fatigue accumulation. Furthermore, this material can serve as a type of luminescent probe for dynamically strengthening visualization in bioimaging.A rtificial molecular switches continue to attract research attention due to their fascinating structures and smart control performances (1-5). Nevertheless, most of these chemical systems work between two or more stable states, and the rest of them requires at least a secondary chemical or energy stimuli, imposing additional inconvenience and the possibility of doubling fatigue accumulation (6-8). Inspired by the underlying mechanism of functional natural systems, scientists began to design and develop molecules with self-recoverability for nonequilibrium action control (9-11). Among the control methods, photocontrol is still a superior fashion because light stimuli are usually rapid and precise, and can be operated remotely (12,13). In contrast to well-studied photochemical processes like photoreaction, photocyclization, and photoisomerization (14, 15), a photocontrol approach with selfrecoverability largely connects to a photoexcitation principle. Thus, it may generally suffer from ultrafast energy relaxation and dissipation, and is extremely difficult to be utilized in materials. Engineering of optoelectronic function and visualization via such a photocontrol method is particularly challenging but also desirable.While luminescent probe techniques enabled a significant scientific advancement in visualized analysis, sensing, and imaging (16)(17)(18), in this work, we expect to impose a photocontrol with self-recoverability into the advancing of operating methods for molecular luminescence. Aggregation-induced emission (AIE) is a type of approach where the molecules can exhibit high luminescence in condensed or constraint states by overcoming the aggregation-caused quenching effect (19)(20)(21). Controllable AIE probes that utilize specific chemical reactions have emerged to facilitate a series of frontier biological usage (22)(23)(24)(25). In contrast, the necessity of spontaneous, repeatable, and rhyth...