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Two-dimensional (2D) materials are of great significance to the materials community for their high surface area and controllable surface properties. However, controlled preparation of 2D structures with biological functions and biodegradable features is considerably hard. In this work, we demonstrate that, by careful selection of building block structures and assembly conditions, the above obstacle can be overcome partially by crystallization-driven self-assembly (CDSA) from PLLA-based diblock glycopolymers. 1D glyco-cylinders and 2D diamond-shaped glyco-platelets with solid or hollow core were achieved, where the latter structures have not been reported in literatures so far. The glyco-platelets further demonstrated exciting macrophage activation efficiency with clear size effect compared to their 1D analogues, which indicated their possible potential in immunological applications.

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Immune checkpoint blockade by anti-PD-L1 monoclonal antibody (αPD-L1) has achieved unprecedented clinical benefits in certain cancers, whereas the therapeutic efficacy is often hindered by immunosuppressive tumor microenvironment mediated by tumor-associated macrophages (TAMs), which leads to innate resistance to this approach. To improve checkpoint blockade efficacy, the amphiphilic diblock copolymers poly(mannopyranoside/galactopyranoside methacrylate)- block-polystyrene are prepared by RAFT polymerization, which are sequentially self-assembled into glycocalyx-mimicking nanoparticles (GNPs) to neutralize TAMs. It is shown that GNPs can be specifically internalized by TAMs via lectin receptors, which results in upregulation of immunostimulatory IL-12 and downregulation of immunosuppressive IL-10, arginase 1, and CCL22, indicating functional reversion of protumor TAMs toward antitumor phenotype. The reversion of TAMs is proved to be mainly controlled by suppressing STAT6 and activating NF-κB phosphorylation. In vivo therapeutic studies have demonstrated that GNPs significantly enhance the therapeutic efficacy of αPD-L1 cancer therapy by reduction of tumor burden. Moreover, combination therapies with GNPs and αPD-L1 greatly improve immunosuppressive tumor microenvironment by reciprocal modulation of tumor-infiltrating effector and regulatory T cells. Notably, for the first time, our results demonstrate the reversion of TAMs and improvement of αPD-L1 cancer therapy by synthetic carbohydrate-containing nanomaterials. This research highlights a promising strategy for optimizing immune checkpoint blockade in cancer immunotherapy.

Glyconanoparticles made by self-assembled glycopolymers currently are practical and efficient mimics of the glycocalyx on cell surfaces. Considering the complexity of the glycocalyx, glyconanoparticles with different sugars on their coronas, i.e., mixed-shell glycomicelles, could be more valuable compared to homoshell micelles. In this paper, we explore the architectural effect of the glyconanoparticle corona on glyconanoparticle macrophage endocytosis and lectin-binding ability. A series of glyconanoparticles composed of a biodegradable polyester backbone functionalized with galactoside or mannoside pendants were designed and prepared. The different architectures explored were single-component (galactoside or mannoside) coronas, homogeneously mixed coronas (MG) made by galactoside-mannoside copolymer chains, and blend-mixed coronas (M/G) constructed from two homoglycopolymers. Nanoparticles with a mixed shell showed a higher efficiency in cellular uptake and lectin-binding than those with a single sugar component. Meanwhile, unexpectedly, MG presented a significantly higher efficiency than M/G, although they had the same particle size and ratio of mannoside to galactoside. We attributed this apparent architectural effect to the difference in the phase behavior between MG and M/G; i.e., the former having a homogeneous corona allowed more sugar-receptor interactions in the contact region, while the latter having phase separation limited the simultaneous interaction of the two kinds of sugar units with the cell receptors.