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ABSTRACT Two‐photon polymerization (TPP) is a powerful technique to create microscale structures with high precision, offering significant potential in tissue engineering and drug delivery. While conventional TPP‐fabricated drug carriers rely on passive encapsulation, these systems often suffer from low payload capacity and diffusion‐controlled release kinetics. To address these challenges, we present the first demonstration of TPP‐printed polyprodrug microstructures, where the therapeutic agent is covalently integrated into the polymer network as the repeating unit itself. Estrogen‐based diacrylate monomers derived from 17β‐estradiol were synthesized via one‐step esterification/transesterification to create a photocurable resin. Curing under flood UV irradiation yielded a rigid thermoset (E′ ∼2.5 GPa at 25°C) with a glass transition temperature of about 50°C. Using TPP, we fabricated various microscale needles (100 × 100 × 400 µm, 2 µm resolution) from this resin, enabling direct printing of intrinsically therapeutic microstructures without post‐processing drug loading. The cured polymer acts as both a structural matrix and a hydrolytically degradable polyprodrug, releasing estradiol through cleavage of ester bonds. By combining covalent drug‐polymer integration with high‐resolution 3D printing, this work establishes a platform for personalized transdermal drug delivery devices with spatially controlled release profiles determined by microstructure design and polymer degradation kinetics. 

The performance of antimicrobial polymers depends sensitively on the type of cationic species, charge density, and spatial arrangement of cations. Here we report antimicrobial polymers bearing unusually bulky tetraaminophosphonium groups as the source of highly delocalized cationic charge. The bulky cations drastically enhanced the biocidal activity of amphiphilic polymers, leading to remarkably potent activity in the submicromolar range. The cationic polynorbornenes with pendent tetraaminophosphonium groups killed over 98% E. coli at a concentration of 0.1 μg/mL and caused a 4-log reduction of E. coli within 2 h at a concentration of 2 μg/mL, showing very rapid and potent bactericidal activity. The polymers are also highly hemolytic at similar concentrations, indicating a biocidal activity profile. Polymers of a similar chemical structure but with more flexible backbones were made to examine the effects of the flexibility of polymer chains on their activity, which turned out to be marginal. We also explore variants with different spacer arm groups separating the cations from the backbone main chain. The antibacterial activity was comparably potent in all cases, but the polymers with shorter spacer arm groups showed more rapid bactericidal kinetics. Interestingly, pronounced counterion effects were observed. Tightly bound PF6– counteranions showed poor activity at high concentrations due to gross aggregate formation and precipitation from the assay media, whereas loosely bound Cl– counterions resulted in very potent activity that monotonically increased with increasing concentration. In this paper, we reveal that bulky phosphonium cations are associated with markedly enhanced biocidal activity, which provides an innovative strategy to develop more effective self-disinfecting materials. 

Abstract Bacterial biofilms are notoriously problematic in applications ranging from biomedical implants to ship hulls. Cationic, amphiphilic antibacterial surface coatings delay the onset of biofilm formation by killing microbes on contact, but they lose effectiveness over time due to non‐specific binding of biomass and biofilm formation. Harsh treatment methods are required to forcibly expel the biomass and regenerate a clean surface. Here, a simple, dynamically reversible method of polymer surface coating that enables both chemical killing on contact, and on‐demand mechanical delamination of surface‐bound biofilms, by triggered depolymerization of the underlying antimicrobial coating layer, is developed. Antimicrobial polymer derivatives based on α‐lipoic acid (LA) undergo dynamic and reversible polymerization into polydisulfides functionalized with biocidal quaternary ammonium salt groups. These coatings kill >99.9% ofStaphylococcus aureuscells, repeatedly for 15 cycles without loss of activity, for moderate microbial challenges (≈10⁵colony‐forming units (CFU) mL⁻¹, 1 h), but they ultimately foul under intense challenges (≈10⁷CFU mL⁻¹, 5 days). The attached biofilms are then exfoliated from the polymer surface by UV‐triggered degradation in an aqueous solution at neutral pH. This work provides a simple strategy for antimicrobial coatings that can kill bacteria on contact for extended timescales, followed by triggered biofilm removal under mild conditions. 

Single-atom catalysts (SACs) exhibit excellent performance for various catalytic reactions but it is still challenging to have adequate total activity for practical applications. Here we report the high-valence, square planar Pt 1 –O 4 as an active site that enables significantly to increase the total activity of the Pt 1 /Fe 2 O 3 SAC with a Pt loading of only ∼30 ppm, which is similar to that of a 1.0 wt% nano-Pt/Fe 2 O 3 , for CO oxidation at 350 °C. Density functional theory calculations reveal that Pt 1 –O 4 catalyzes CO oxidation through a non-classical Mars–van Krevelen mechanism. The adsorbed O 2 on Pt 1 atoms activates the coordination oxygen in the Pt 1 –O 4 configuration, and then a barrierless O 2 dissociation occurs on the Pt 1 –Fe 2 triangle to replenish the consumed coordination oxygen by the cooperative action of Pt 5d and Fe 3d electrons. This work provides a new fundamental understanding of oxidation catalysis on stable and active SACs, providing guidance for rationally designing future heterogeneous catalysts.