Solution self-assembly of block copolymers (BCPs) typically generates spheres, rods, and vesicles. The reproducible bottom-up fabrication of stable planar nanostructures remains elusive due to their tendency to bend into closed bilayers. This morphological vacancy renders the study of shape effects on BCP nanocarrier-cell interactions incomplete. Furthermore, the fabrication of single BCP assemblies with built-in drug delivery functions and geometry-optimized performance remains a major challenge. We demonstrate that PEG-b-PCPTM polyprodrug amphiphiles, where PEG is poly(ethylene glycol) and PCPTM is polymerized block of reduction-cleavable camptothecin (CPT) prodrug monomer, with >50 wt % CPT loading content can self-assemble into four types of uniform nanostructures including spheres, large compound vesicles, smooth disks, and unprecedented staggered lamellae with spiked periphery. Staggered lamellae outperform the other three nanostructure types, exhibiting extended blood circulation duration, the fastest cellular uptake, and unique internalization pathways. We also explore shape-modulated CPT release kinetics, nanostructure degradation, and in vitro cytotoxicities. The controlled hierarchical organization of polyprodrug amphiphiles and shape-tunable biological performance opens up new horizons for exploring next-generation BCP-based drug delivery systems with improved efficacy.

We report on the fabrication of photochromic polymersomes exhibiting photoswitchable and reversible bilayer permeability from newly designed poly(ethylene oxide)-b-PSPA (PEO-b-PSPA) diblock copolymers, where SPA is spiropyran (SP)-based monomer containing a unique carbamate linkage. Upon self-assembling into polymersomes, SP moieties within vesicle bilayers undergo reversible phototriggered isomerization between hydrophobic spiropyran (SP, λ2 > 450 nm irradiation) and zwitterionic merocyanine (MC, λ1 < 420 nm irradiation) states. For both SP and MC polymersomes, their microstructures are stabilized by multiple cooperative noncovalent interactions including hydrophobic, hydrogen bonding, π-π stacking, and paired electrostatic (zwitterionic) interactions, with the latter two types being exclusive for MC polymersomes. Control experiments using analogous block copolymers of hydrophobic SP monomer with a carbonate linkage (SPO) and conventional spiropyran methacrylate monomer (SPMA) containing a single ester functionality were then conducted, revealing that carbamate-incurred hydrogen bonding interactions in PEO-b-PSPA are crucial for polymersome stabilization in the zwitterionic MC state. Moreover, reversible phototriggered SP-to-MC polymersome transition is accompanied by membrane polarity and permeability switching from being nonimpermeable to selectively permeable toward noncharged, charged, and zwitterionic small molecule species below critical molar masses. Intriguingly, UV-actuated MC polymersomes possess two types of release modules: (1) sustained release upon short UV irradiation duration by taking advantage of the unexpectedly slow spontaneous MC-to-SP transition kinetics (t1/2 > 20 h) under dark conditions; (2) on-demand and switchable release under alternated UV-vis light irradiation. We further demonstrate photoswitchable spatiotemporal release of 4',6-diamidino-2-phenylindole (DAPI, cell nuclei-staining dye) within living HeLa cells.

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The low capacity and unsatisfactory rate capability of hard carbon still restricts its practical application for Li/K‐ion batteries. Herein, a low‐cost and large‐scale method is developed to fabricate phosphorus‐doped hard carbon (PHC‐700) by crosslinking phosphoric acid and epoxy resin and followed by annealing at 700 °C. H3PO4 acts not only as a crosslinker to solidify epoxy resin for promoting the degree of graphitization and lowering the specific surface area, but also as phosphorus source for forming PC and PO bonds, thus providing more active sites for Li/K storage. As a result, the PHC‐700 electrode delivers a highly reversible capacity of 1294.8 mA h g−1 at 0.1 A g−1 and a capacity of 214 mA h g−1 after 10 000 cycles at 10 A g−1. As for potassium‐ion batteries, PHC‐700 exhibits a reversible capacity of 381.9 mA h g−1 at 0.1 A g−1 and a capacity of 260 mA h g−1 after 1000 cycles at 0.2 A g−1. In situ Raman and in situ NMR measurements reveal that the P‐containing bonds can enhance the adsorption to alkali metal ions, and the PC bond can participate in electrochemical redox reaction by forming Lix PCy . Additionally, P‐doped hard carbon shows better structural/interfacial stability for improved long‐term cycling stability.

We report on the fabrication of dynamic covalent shell cross-linked (SCL) micelles with hydrophobic cores conjugated with photocaged chemotherapeutic drugs and coronas functionalized with ligands for tumor cell targeting. Two types of amphiphilic diblock copolymers, P(CL-g-CPT)-b-P(OEGMA-co-MAEBA)-CPT and PCL-b-P(OEGMA-co-MAEBA-co-FA), were synthesized via the combination of ring-opening copolymerization (ROP) of ε-caprolactone (CL) and 2-bromo-ε-caprolactone (CL-Br), atom transfer radical polymerization (ATRP) of oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA) and p-(methacryloxyethoxy) benzaldehyde (MAEBA) comonomers, and “click” post-functionalization with photocaged camptothecin (CPT) prodrug and alkynyl-functionalized folic acid (FA) moieties, respectively. Mixed micelles coassembled from PCL-b-P(OEGMA-co-MAEBA-co-FA) and P(CL-g-CPT)-b-P(OEGMA-co-MAEBA)-CPT possess hydrophobic cores conjugated with photocaged CPT prodrugs and hydrophilic outer coronas covalently attached with aldehyde groups and FA moieties for subsequent shell cross-linking and cancer cell targeting. Shell cross-linking was performed at pH 6.2 upon addition of difunctional cross-linker, dithiol bis(propanoic dihydrazide) (DTP), under the catalysis of aniline. The obtained FA-decorated SCL micelles contain acylhydrazone and disulfide linkages in the outer coronas, which can be de-cross-linked under two biologically relevant conditions, mildly acidic or reductive microenvironments, that is, endosomal/lysosomal pH or high GSH level in the cytosol. The cleavage of caged CPT drug within the cores of SCL micelles can be effectively actuated under photo irradiation, whereas its diffusion out of micellar nanocarriers can be further modulated by pH and thiol levels due to the dually responsive nature of DTP cross-linker. Compared with the control, FA-decorated SCL micelles can more efficiently enter folate-receptor expressing cancer cells than folate-receptor deficient ones. Cell viability assays revealed that SCL micelles displayed at least ∼9.7-fold enhanced cytotoxicity upon light irradiation. The reported targeting ligand decorated and prodrug-conjugated dynamic covalent SCL micelles exert intricate control concerning micellar stability, cancer cell targeting, photo-triggered parent drug release with photoactivated cytotoxicity, and tunable drug release profiles. All of these augur well for their potential application as a novel integrated platform for targeted drug delivery in cancer chemotherapy.