The authors report a new biomimetic nanodelivery platform in which polymeric nanoparticles enclosed in the plasma membrane of human platelets are used for disease-relevant targeting, and the therapeutic potential of the concept is demonstrated in animal models of coronary restenosis and systemic bacterial infection. The properties of blood platelets — small discoid cells that carry out a broad range of functions related to haemostasis — marks them out as prime candidates to form the basis of drug delivery systems. These authors report a new nanoparticle-based delivery platform, in which polymeric nanoparticles are enclosed in the plasma membrane of human platelets. They demonstrate the use of these platelet-membrane cloaked nanoparticles for antibiotic delivery in murine models for cardiovascular disease and systemic bacterial infection. Development of functional nanoparticles can be encumbered by unanticipated material properties and biological events, which can affect nanoparticle effectiveness in complex, physiologically relevant systems1,2,3. Despite the advances in bottom-up nanoengineering and surface chemistry, reductionist functionalization approaches remain inadequate in replicating the complex interfaces present in nature and cannot avoid exposure of foreign materials. Here we report on the preparation of polymeric nanoparticles enclosed in the plasma membrane of human platelets, which are a unique population of cellular fragments that adhere to a variety of disease-relevant substrates4,5,6,7. The resulting nanoparticles possess a right-side-out unilamellar membrane coating functionalized with immunomodulatory and adhesion antigens associated with platelets. Compared to uncoated particles, the platelet membrane-cloaked nanoparticles have reduced cellular uptake by macrophage-like cells and lack particle-induced complement activation in autologous human plasma. The cloaked nanoparticles also display platelet-mimicking properties such as selective adhesion to damaged human and rodent vasculatures as well as enhanced binding to platelet-adhering pathogens. In an experimental rat model of coronary restenosis and a mouse model of systemic bacterial infection, docetaxel and vancomycin, respectively, show enhanced therapeutic efficacy when delivered by the platelet-mimetic nanoparticles. The multifaceted biointerfacing enabled by the platelet membrane cloaking method provides a new approach in developing functional nanoparticles for disease-targeted delivery.

Advances in bioinspired design principles and nanomaterials have led to tremendous progress in autonomously moving synthetic nano/micromotors with diverse functionalities in different environments. However, a significant gap remains in moving nano/micromotors from test tubes to living organisms for treating diseases with high efficacy. Here we present the first, to our knowledge, in vivo therapeutic micromotors application for active drug delivery to treat gastric bacterial infection in a mouse model using clarithromycin as a model antibiotic and Helicobacter pylori infection as a model disease. The propulsion of drug-loaded magnesium micromotors in gastric media enables effective antibiotic delivery, leading to significant bacteria burden reduction in the mouse stomach compared with passive drug carriers, with no apparent toxicity. Moreover, while the drug-loaded micromotors reach similar therapeutic efficacy as the positive control of free drug plus proton pump inhibitor, the micromotors can function without proton pump inhibitors because of their built-in proton depletion function associated with their locomotion.

Sepsis, resulting from uncontrolled inflammatory responses to bacterial infections, continues to cause high morbidity and mortality worldwide. Currently, effective sepsis treatments are lacking in the clinic, and care remains primarily supportive. Here we report the development of macrophage biomimetic nanoparticles for the management of sepsis. The nanoparticles, made by wrapping polymeric cores with cell membrane derived from macrophages, possess an antigenic exterior the same as the source cells. By acting as macrophage decoys, these nanoparticles bind and neutralize endotoxins that would otherwise trigger immune activation. In addition, these macrophage-like nanoparticles sequester proinflammatory cytokines and inhibit their ability to potentiate the sepsis cascade. In a mouse Escherichia coli bacteremia model, treatment with macrophage mimicking nanoparticles, termed MΦ-NPs, reduced proinflammatory cytokine levels, inhibited bacterial dissemination, and ultimately conferred a significant survival advantage to infected mice. Employing MΦ-NPs as a biomimetic detoxification strategy shows promise for improving patient outcomes, potentially shifting the current paradigm of sepsis management. Significance Clinical evidence has indicated that the systemic spread of endotoxins from septic infection plays a crucial role in the pathogenesis of Gram-negative bacterial sepsis. However, currently there are no effective ways to manage the diverse endotoxins released by different bacterial genus, species, and strain. Herein, we demonstrate the therapeutic potential of a macrophage-like nanoparticle for sepsis control through a powerful two-step neutralization process: endotoxin neutralization in the first step followed by cytokine sequestration in the second step. The biomimetic nanoparticles possess an antigenic exterior identical to macrophage cells, thus inheriting their capability to bind to endotoxins and proinflammatory cytokines. This detoxification strategy may provide a first-in-class treatment option for sepsis and ultimately improve the clinical outcome of patients.