Solid tumors are regarded as complex evolving systems rather than simple diseases. Self-adaptive synthetic therapeutics are required to cope with the challenges of entire tumors; however, limitations in accurate positioning and destruction of hypoxic niches seriously hinder complete tumor eradication. In this study, we engineer a molecular nanoassembly of sorafenib and a hypoxia-sensitive cyanine probe (CNO) to facilitate periphery/center synergistic cancer therapies. The self-adaptive nanoassembly with cascade drug release features not only effectively kills the peripheral tumor cells in normoxic rims but precisely illuminates hypoxic niches following the reduction of CNO by nitroreductase. More important, CNO is found to synergistically induce tumor ferroptosis with sorafenib via nicotinamide adenine dinucleotide phosphate (NADPH) depletion in hypoxic niches. As expected, the engineered nanoassembly demonstrates self-adaptive hypoxic illumination and periphery/center synergetic tumor eradication in colon and breast cancer BALB/c mouse xenograft models. This study advances turn-on hypoxia illumination and chemo-ferroptosis toward clinical applicability.
Cells and exosomes derived from them are extensively used as biological carrier systems. Cells demonstrate superior targeting specificity and prolonged circulation facilitated by their rich array of surface proteins, while exosomes, due to their small size, cross barriers and penetrate tumors efficiently. However, challenges remain, cells’ large size restricts tissue penetration, and exosomes have limited targeting accuracy and short circulation times. To address these challenges, we developed a novel concept termed exosomal spheres. This approach involved incorporating platelet-derived exosomes shielded with phosphatidylserine (PS) and linked via pH-sensitive bonds for drug delivery applications. The study demonstrated that, compared with exosomes, the exosomal spheres improved blood circulation through the upregulation of CD47 expression and shielding of phosphatidylserine, thereby minimizing immune clearance. Moreover, the increased expression of P-selectin promoted adhesion to circulating tumor cells, thereby enhancing targeting efficiency. Upon reaching the tumor site, the hydrazone bonds of exosome spheres were protonated in the acidic tumor microenvironment, leading to disintegration into uniform-sized exosomes capable of deeper tumor penetration compared to platelets. These findings suggested that exosome spheres addressed the challenges and offered significant potential for efficient and precise drug delivery.
Neural progenitor cells (NPCs) are widely recognized as promising seed cells for the treatment of neurodegenerative diseases due to their inherent potential to differentiate into functional neurons. However, due to the low differentiation efficiency, their practical application in neural repair remains a significant challenge. In this work, we present a novel, non‐invasive strategy to enhance the neuronal differentiation of NPCs through photothermal‐pyroelectric stimulation. Specifically, a hybrid film was fabricated by coating BaTiO 3 (BTO) nanocrystals – comprising either nanoparticles or nanosheets – onto the surface of a CNT@PDMS composite membrane. Under periodic light irradiation, the photothermal effect triggered rapid temperature oscillations, which activated BTO's pyroelectric effect, generating localized electric stimulation that promoted neuronal differentiation of NPCs. Immunofluorescent staining and Western blot analysis further confirmed that the observed enhancement in neural differentiation was mediated by the activation of Ca 2+ signaling and the PI3K/Akt pathway. Moreover, comparative experiments revealed that BTO nanosheets with highly exposed (001) facets exhibited markedly enhanced neurogenic differentiation capabilities relative to BTO nanoparticles, highlighting the facet‐dependent pyroelectric effect. This work presents wireless photothermal‐pyroelectric stimulation for neural differentiation and, for the first time, proposes a pyroelectric regenerative medicine for the non‐invasive repair of damaged neural tissue.
Covalent organic frameworks (COFs) are crystalline materials with intrinsic porosity that offer a wide range of potential applications spanning diverse fields. Yet, the main goal in the COF research area is to achieve the most stable thermodynamic product while simultaneously targeting the desired size and structure crucial for enabling specific functions. While significant progress has been made in the synthesis and processing of 2D COFs, the development of processable 3D COF nanocrystals remains challenging. Here, we present a water-based nanoreactor technology for producing processable sub-40 nm 3D COF nanoparticles at ambient conditions. Significantly, this technology not only improves the processability of the synthesized 3D COF, but also unveils exciting possibilities for their utilization in previously unexplored domains, such as nano/microrobotics and biomedicine, which were limited by larger crystallites.
Magnetic microrobots have been developed for navigating microscale environments by means of remote magnetic fields. However, limited propulsion speeds at small scales remain an issue in the maneuverability of these devices as magnetic force and torque are proportional to their magnetic volume. Here, we propose a microrobotic superstructure, which, as analogous to a supramolecular system, consists of two or more microrobotic units that are interconnected and organized through a physical (transient) component (a polymeric frame or a thread). Our superstructures consist of microfabricated magnetic helical micromachines interlocked by a magnetic gelatin nanocomposite containing iron oxide nanoparticles (IONPs). While the microhelices enable the motion of the superstructure, the IONPs serve as heating transducers for dissolving the gelatin chassis via magnetic hyperthermia. In a practical demonstration, we showcase the superstructure's motion with a gradient magnetic field in a large channel, the disassembly of the superstructure and release of the helical micromachines by a high-frequency alternating magnetic field, and the corkscrew locomotion of the released helices through a small channel via a rotating magnetic field. This adaptable microrobotic superstructure reacts to different magnetic inputs, which could be used to perform complex delivery procedures within intricate regions of the human body.