Boston Ivy-Inspired Disc-Like Adhesive Microparticles for Drug Delivery

Bio-inspired drug delivery systems: A new attempt from bioinspiration to biomedical applications

Natural organisms have evolved sophisticated and multiscale hierarchical structures over time to enable survival. Currently, bionic design is revolutionizing drug delivery systems (DDS), drawing inspiration from the structure and properties of natural organisms that offer new possibilities to overcome the challenges of traditional drug delivery systems. Bionic drug delivery has contributed to a significant improvement in therapeutic outcomes, providing personalized regimens for patients with various diseases and enhancing both their quality of life and drug efficacy. Therefore, it is important to summarize the progress made so far and to discuss the challenges and opportunities for future development. Herein, we review the recent advances in bio-inspired materials, bio-inspired drug vehicles, and drug-loading platforms of biomimetic structures and properties, emphasizing the importance of adapting the structure and function of organisms to meet the needs of drug delivery systems. Finally, we highlight the delivery strategies of bionics in DDS to provide new perspectives and insights into the research and exploration of bionics in DDS. Hopefully, this review will provide future insights into utilizing biologically active vehicles, bio-structures, and bio-functions, leading to better clinical outcomes.

Chinese herb pollen derived micromotors as active oral drug delivery system for gastric ulcer treatment

Considerable efforts have been devoted to treating gastric ulcers. Attempts in this field tend to develop drug delivery systems with prolonged gastric retention time. Herein, we develop novel Chinese herb pollen-derived micromotors as active oral drug delivery system for treating gastric ulcer. Such Chinese herb pollen-derived micromotors are simply produced by asymmetrically sputtering Mg layer onto one side of pollen grains. When exposed to gastric juice, the Mg layer can react with the hydrogen ions, resulting in intensive generation of hydrogen bubbles to propel the micromotors. Benefiting from the autonomous motion and unique spiny structure, our micromotors can move actively in the stomach and adhere to the surrounding tissues. Besides, their special architecture endows the micromotors with salient capacity of drug loading and releasing. Based on these features, we have demonstrated that our Chinese herb pollen-derived micromotors could effective deliver berberine hydrochloride and show desirable curative effect on the gastric ulcer model of mice. Therefore, these Chinese herb pollen-derived micromotors are anticipated to serve as promising oral drug delivery carriers for clinical applications.

Erythrocyte-Inspired Functional Materials for Biomedical Applications

Erythrocytes are the most abundant cells in the blood. As the results of long-term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte-inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte-inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte-inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications.

Hierarchical Microparticles Delivering Oxaliplatin and NLG919 Nanoprodrugs for Local Chemo-immunotherapy

Chemo-immunotherapy shows promising antitumor therapeutic outcomes for many primary cancers. Research in this area has been focusing on developing an ideal formula that enables the potent efficacy of chemo-immunotherapy in combating various cancers with reduced systemic toxicity. Herein, we present novel hierarchical hydrogel microparticles (M_DDP) delivering oxaliplatin and NLG919 nanoprodrugs for local chemo-immunotherapy with desired features. The oxaliplatin prodrug and NLG919 were efficiently loaded in the dual-drug polymeric nanoparticles (DDP NPs), which were further encapsulated into a M_DDP by using microfluidic technology. When delivered to the tumor site, the DDP NPs will be sustainedly released from the M_DDP and retained locally to reduce systemic toxicity. After being endocytosed by cancer cells, the cytotoxic oxaliplatin and NLG919 could be successfully triggered to release from DDP NPs in a chain-shattering manner, leading to the immunogenic cell death (ICD) of tumor cells and the suppression of intratumoral immunosuppressive Tregs, respectively. With the assistance of an immune modulator, the chemotherapeutics-induced ICD could trigger robust systemic antitumor immune responses, presenting superior synergistic antitumor efficacies. Thus, the hierarchical microparticles could substantially inhibit the growth of mouse subcutaneous colorectal tumors, breast tumors, and colorectal tumors with large initial sizes via synergized chemo-immunotherapy, showing great potential in the practical clinical application of oncotherapy.

Microfluidic Preparation of Gelatin Methacryloyl Microgels as Local Drug Delivery Vehicles for Hearing Loss Therapy

Local drug delivery has become an effective method for disease therapy in fine organs including ears, eyes, and noses. However, the multiple anatomical and physiological barriers, unique clearance pathways, and sensitive perceptions characterizing these organs have led to suboptimal drug delivery efficiency. Here, we developed dexamethasone sodium phosphate-encapsulated gelatin methacryloyl (Dexsp@GelMA) microgel particles, with finely tunable size through well-designed microfluidics, as otic drug delivery vehicles for hearing loss therapy. The release kinetics, encapsulation efficiency, drug loading efficiency, and cytotoxicity of the GelMA microgels with different degrees of methacryloyl substitution were comprehensively studied to optimize the microgel formulation. Compared to bulk hydrogels, Dexsp@GelMA microgels of certain sizes hardly cause air-conducted hearing loss in vivo. Besides, strong adhesion of the microgels on the round window membrane was demonstrated. Moreover, the Dexsp@GelMA microgels, via intratympanic administration, could ameliorate acoustic noise-induced hearing loss and attenuate hair cell loss and synaptic ribbons damage more effectively than Dexsp alone. Our results strongly support the adhesive and intricate microfluidic-derived GelMA microgels as ideal intratympanic delivery vehicles for inner ear disease therapies, which provides new inspiration for microfluidics in drug delivery to the fine organs.

Bio-Inspired Bianisotropic Magneto-Sensitive Elastomers with Excellent Multimodal Transformation

Magneto-sensitive soft materials that can accomplish fast, remote, and reversible shape morphing are highly desirable for practical applications including biomedical devices, soft robotics, and flexible electronics. In conventional magneto-sensitive elastomers (MSEs), there is a tradeoff between employing hard magnetic particles with costly magnetic programming and utilizing soft magnetic particle chains causing tedious and small deformation. Here, inspired by the shape and movement of mimosa, a novel soft magnetic particle doped shape material bianisotropic magneto-sensitive elastomer (SM bianisotropic MSE) with multimodal transformation and superior deformability is developed. The high-aspect-ratio shape anisotropy and the material anisotropy in which the magnetic particles are arranged in a chainlike structure together impart magnetic anisotropy to the SM bianisotropic MSE. A magneto-elastic analysis model is proposed, and it is elucidated that magnetic anisotropy leads to peculiar field-direction-dependent multimodal transformation. More importantly, a quadrilateral assembly and a regular hexagon assembly based on this SM bianisotropic MSE are designed, and they exhibit 2.4 and 1.7 times the deformation capacity of shape anisotropic samples, respectively. By exploiting the multidegree of freedom and excellent deformability of the SM bianisotropic MSE, flexible logic switches and ultrasoft magnetic manipulators are further demonstrated, which prove its potential applications in future intelligent flexible electronics and autonomous soft robotics.

Prebiotics and Postbiotics Synergistic Delivery Microcapsules from Microfluidics for Treating Colitis

Manipulation of gut microbiota by bacterial metabolites has shown protective effects against colitis; while the efficacy is strictly limited by the poor oral delivery efficiency and single drug usage. Here, a novel prebiotics and postbiotics synergistic delivery microcapsule composed of indole-3-propionic acid (IPA) postbiotic and three prebiotics including alginate sodium, resistant starch (RS), and chitosan via microfluidic electrospray for preventing and treating colitis are proposed. It is found that oral administration of IPA microcapsules (IPA@MC) to mice can exert significant protective effects to colitis, suggesting the therapeutic synergy between prebiotics and postbiotics. Furthermore, the mechanism of the IPA@MC is revealed in modulating the gut microbiota, that is by significantly increasing the overall richness and abundance of short-chain fatty acids (SCFA) producing bacteria such as Faecalibacterium and Roseburia. These results indicate that the prebiotics and postbiotics synergistic delivery microcapsules are ideal candidates for treating colitis.

Photopolymerized 3D Printing Scaffolds with Pt(IV) Prodrug Initiator for Postsurgical Tumor Treatment

Biomedical scaffolds have shown great success in postsurgical tumor treatment; their current efforts are focusing on eradicating residual tumor cells and circulating tumor cells and simultaneously repairing postoperative tissue defects. Herein, we report a novel photopolymerized 3D scaffold with Pt(IV) prodrug initiator to achieve the desired features for tumor comprehensive therapy. The Pt-GelMA scaffold was fabricated from the microfluidic 3D printing of methacrylate gelatin (GelMA) bioinks through a Pt(IV)-induced photocrosslinked process without any other additional photoinitiator and chemotherapeutic drug. Thus, the resultant scaffold displayed efficient cell killing ability against breast cancer cells in vitro and significantly inhibited the local tumor growth and distant metastases on an orthotopic postoperative breast cancer model in vivo. Besides, benefiting from their ordered porous structures and favorable biocompatibility, the scaffolds supported the cell attachment, spreading, and proliferation of normal cells in vitro; could facilitate the nutrient transportation; and induced new tissue ingrowth for repairing tissue defects caused by surgery. These properties indicate that such 3D printing scaffold is a promising candidate for efficient postoperative tumor treatment in the practical application.

Suction-Cup-Inspired Adhesive Micromotors for Drug Delivery

Micromotors have opened novel avenues for drug delivery due to their capacity for self-propelling. Attempts in this field trend towards ameliorating their functions to promote their clinical applications. In this paper, an ingenious suction-cup-inspired micromotor is presented with adhesive properties for drug delivery in the stomach. The micromotors are fabricated by using hydrogel replicating the structure of suction-cup-like microparticles, which derive from self-assembly of colloidal crystals under rapid solvent extraction, followed by loading magnesium (Mg) in the bottom spherical surface. The Mg-loaded micromotors can realize spontaneous movement due to the continual generation of hydrogen bubbles in gastric juice. The combination of unique suction-cup-like structure with excellent motion performance makes the micromotor an ideal carrier for drug delivery as they can efficiently adhere to the tissue. Moreover, benefiting from the porous structure, the hydrogel micromotors exhibit a high volume-surface ratio, which enables efficient drug loading. It is demonstrated that the suction-cup-inspired micromotors can adhere efficiently to the ulcer-region in the stomach and release drugs due to their distinctive architecture and spontaneous motion, exhibiting desirable curative effect of gastric ulcer. Thus, the suction-cup-inspired micromotors with adhesive properties are expected to advance the development of micromotor in clinical applications.

Platelet Membrane-Coated Nanocarriers Targeting Plaques to Deliver Anti-CD47 Antibody for Atherosclerotic Therapy

Atherosclerosis, the principle cause of cardiovascular disease (CVD) worldwide, is mainly characterized by the pathological accumulation of diseased vascular cells and apoptotic cellular debris. Atherogenesis is associated with the upregulation of CD47, a key antiphagocytic molecule that is known to render malignant cells resistant to programmed cell removal, or "efferocytosis." Here, we have developed platelet membrane-coated mesoporous silicon nanoparticles (PMSN) as a drug delivery system to target atherosclerotic plaques with the delivery of an anti-CD47 antibody. Briefly, the cell membrane coat prolonged the circulation of the particles by evading the immune recognition and provided an affinity to plaques and atherosclerotic sites. The anti-CD47 antibody then normalized the clearance of diseased vascular tissue and further ameliorated atherosclerosis by blocking CD47. In an atherosclerosis model established in ApoE^-/- mice, PMSN encapsulating anti-CD47 antibody delivery significantly promoted the efferocytosis of necrotic cells in plaques. Clearing the necrotic cells greatly reduced the atherosclerotic plaque area and stabilized the plaques reducing the risk of plaque rupture and advanced thrombosis. Overall, this study demonstrated the therapeutic advantages of PMSN encapsulating anti-CD47 antibodies for atherosclerosis therapy, which holds considerable promise as a new targeted drug delivery platform for efficient therapy of atherosclerosis.