ACS Macro Letters最新文献

Complex coacervates have emerged as versatile platforms for protein encapsulation, enabling enzymatic catalysis in aqueous environments. Despite their potential, applications of coacervates are limited by the substrate solubility in water. In this study, we present a protocol to stabilize enzyme-loaded coacervate droplets in water-immiscible organic solvents via the formation of highly stable emulsions. These emulsions were formed using coacervates composed of poly(diallyldimethylammonium hydroxide) and poly(acrylic acid), stabilized by a polystyrene-based, amphiphilic, anionic copolymer in toluene, chlorobenzene, chloroform, and dichloromethane. The resulting microdroplets display exceptional resistance to coalescence, including after centrifugation, and remain stable for weeks. This stability facilitates their separation and redispersion for use in repeated catalytic applications. Using α-chymotrypsin as a model enzyme, we show that the aqueous microenvironment within the droplets maintains enzyme stability over time and enables biocatalysis in nonaqueous media.

Conjugated polymers with both strong near-infrared (NIR) absorption coefficients and high photothermal conversion efficiencies represent a class of promising photothermal nanomaterials. However, most donor–acceptor (D-A) type conjugated polymers suffer from relatively weak absorption coefficients. Herein, a conjugated polymer derived from quinoidal benzodifurandione-alt-bithiophene imide (PBFDO-BTI) was synthesized and developed as a novel therapeutic agent for photothermal therapy (PTT). Benefiting from its intrinsic quinoidal structure and acceptor–acceptor (A-A) configuration, PBFDO-BTI exhibits an unexpectedly ultrahigh mass extinction coefficient of 162.9 L g^–1 cm^–1 at 808 nm. Additionally, transient absorption measurements reveal that the excited-state lifetime of PBFDO-BTI is merely 2.44 ps. Owing to its strong NIR absorption and ultrafast internal conversion process, the water-soluble nanoparticles based on PBFDO-BTI demonstrate excellent photothermal conversion performance, achieving a photothermal conversion efficiency of up to 74.5% at 808 nm. Moreover, these PBFDO-BTI-based water-soluble nanoparticles exhibit remarkable PTT efficacy both in vitro and in vivo.

Stereochemistry and the monomer sequence of biopolymers are key parameters that guide self assemblies and functions of biological systems. However, abiotic macromolecules are still behind in mimicking the selective interactions that drive the complexity of living matter. Herein, we report that synthetic, precise oligourethanes can form noncovalent assemblies leading to supramolecular gels. Notably, the process of supramolecular gelation occurs outside the aqueous environment and exhibits reversible adaptive behavior in response to external stimuli, including ultrasound and temperature. Gel formation and its properties are guided by the information encoded in the sequence and stereochemistry of their backbones and depend on the solvent environment. The performed spectroscopic studies reveal that the stereochemical control governing the oligourethane conformations, in turn, directs the higher-order assembly pathway. This work demonstrates the compelling property of abiotic oligourethanes that opens up opportunities to fine-tune self-assembly features using sequence control previously thought to be confined to biopolymers. Our findings open up new possibilities for designing synthetic polyurethane materials that can operate in nonphysiological environments while mimicking biopolymer features, thereby laying the foundation for applications in adaptive soft materials, organic-phase catalysis, and chemical sensing, utilizing ultrasonic-based technologies.

Accurate identification of tracer particles contributing to diffusing wave spectroscopy (DWS) is essential for reliable microrheology but remains challenging in Pickering emulsions. Herein, we demonstrate that colloids are the tracer particles in Pickering emulsions of varying droplet scales, i.e., macroemulsion or microemulsion. Simulations reveal that colloids are more mobile than droplets, thereby dominating the decay of the intensity autocorrelation function. This conclusion is further supported by the agreement between the viscoelastic parameters from rotational rheometry and those calculated from DWS using the colloidal radius. The reason is that colloids are inherently orders of magnitude smaller than droplets, leading to much faster Brownian motion. This work provides a strategy for tracer particles identification and for enhancing the utility of DWS in the accurate characterization of Pickering emulsion microrheology.

This work investigates the self-assembly behavior of binary blends composed of isomeric AB diblock copolymers that share identical compositions but varying block geometries. A nonuniform distribution of side chains breaks the intrinsic symmetry along the polymer backbone, resulting in chain conformations deviating from random coils. When blocks possess complementary geometries, their conformations average out, resembling those of uniform analogs. By tuning of the degree of complementarity and blending ratio, the system undergoes phase transitions from hexagonally packed cylinders to Frank–Kasper A15 sphere and further to dodecagonal quasicrystal (DDQC) and σ phase. The side chains adjacent to the block junction dominate local packing frustration and chain stretching, thereby dictating the phase behavior. This work presents an efficient approach for precisely tuning conformational asymmetry, enabling access to complex spherical packing phases without changing the overall chemistry and composition.

Analogous to temperature-gradient interaction chromatography, temperature-gradient elution three-dimensional correlation thermal field-flow fractionation (TGE-3DCoTF3) coupled with quintuple-detection provides high-resolution analysis of ultrahigh-molar-mass poly(styrene-co-maleic anhydride) synthesized via biradical photoinitiation. TGE-3DCoTF3 resolves more than 3 orders of magnitude in molar-mass, cleanly separating residual monomers and oligomers from megadalton copolymers while preserving their integrity. Multidetector correlation yields molar-mass, three independent radii, intrinsic viscosity, diffusion coefficient, thermal diffusion coefficient (D_T) and UV–vis spectra. Differential UV–vis absorptivity distinguishes unreacted monomers from copolymers, enabling conversion analysis. D_T serves as a pseudospectroscopic probe, confirming constant styrene-to-maleic anhydride ratios and truly alternating copolymerization. Comparative analysis of “lower” and “higher” ultrahigh-molar-mass copolymers differing by a factor of 2 in degrees of polymerization reveals identical thermophoretic behavior but distinct coil compactness, evidencing transitions toward denser core–shell morphology. Collectively, TGE-3DCoTF3 offers a nondestructive, multidimensional benchmark for elucidating molar-mass, size, and compositional dynamics in polymers that challenge conventional SEC characterization.

Spherical polyelectrolyte brushes (SPBs) have been of great interest in biomedicine, particularly in gene delivery, yet their brush architectures are commonly fixed, showing limited tunability and responsiveness. Herein, we report a light-controllable supramolecular SPB (AuNP@CDs@Azo-PD) constructed by assembling azobenzene-terminated poly(2-(dimethylamino)ethyl methacrylate) (Azo-PD) onto β-cyclodextrin-functionalized gold nanoparticles (AuNP@CDs) via reversible host–guest interactions. The resulting nanostructure exhibits a core–shell architecture with a brush-like polymer corona. Characterization of the system through dynamic light scattering (DLS) and UV–vis spectroscopy confirmed the successful formation of the nanocarrier and its ability to undergo controlled structural transitions under UV irradiation. The SPB system was further evaluated for its gene delivery capability, showing excellent biocompatibility and effective plasmid DNA encapsulation, with protection against serum nucleases. In vitro transfection studies revealed that AuNP@CDs@Azo-PD achieved comparable transfection efficiency to Lipofectamine 3000, with efficient gene expression and suppression of the PI3K/AKT signaling pathway. Additionally, UV-triggered release of the PTEN gene resulted in enhanced tumor suppression effects, including reduced cell proliferation, migration, and increased apoptosis. These findings demonstrate the potential of AuNP@CDs@Azo-PD as a versatile and responsive nanoplatform for controlled gene delivery and cancer therapy.

Herein, an innovative two-stage curing strategy based on poly(thioctic acid) is proposed for developing robust underwater epoxy adhesives. The epoxy curing agent with an adaptive molecular architecture is first synthesized via solvent-free ring-opening polymerization of naturally occurring thioctic acid propelled by dynamic thiol–disulfide exchange. Upon combining the epoxy resin with poly(thioctic acid), the water-resistant long-chain polymers that effectively expel interfacial water and establish multiple interfacial interactions are formed by the first-stage curing via a click reaction between thiol and epoxy groups initiated by the thiol–disulfide exchange mechanism. Subsequently, the second-stage curing is triggered via carboxyl–epoxy reactions and leads to the formation of cross-linked networks. This strategy endows the developed underwater epoxy adhesive with underwater bonding strength up to 16.4 MPa and green recyclability that can be repeatedly disassembled.

Conventional synthetic polymers face a critical sustainability challenge due to their environmental persistence. This study introduces a sustainable polymer platform combining environmental degradability with exceptional material stability through direct cyclobutane incorporation into polymer backbones via ring-opening metathesis polymerization (ROMP). Capitalizing on cyclobutane’s high ring strain (26 kcal/mol), these polymers undergo ultrasound-triggered backbone scission, and the resulting polymers achieve three critical advances: ultrasound-triggered degradation via selective backbone scission, great resistance to harsh acidic (pH 1) and thermal environments, and tunable mechanical properties controlled by cyclobutane content (0–22 mol %). Unlike existing systems, this design maintains structural integrity during operation but undergoes rapid backbone scission under targeted mechanical stress, resolving the historical trade-off between durability and degradability. The ROMP platform’s architectural precision supports the scalable synthesis of high-performance polymers adaptable to industrial applications. By integrating on-demand recyclability through mechanochemical pathways, this work provides a blueprint for next-generation sustainable materials that simultaneously meets operational demands and circular economy requirements.

The design of red-emissive nonconjugated polymers and the interpretation of their photophysical behavior remain a significant challenge in materials chemistry. Clustering-triggered emission (CTE), driven by through-space donor–acceptor (D–A) interactions within polymeric assemblies, is a key principle governing such nonconventional luminescence. Herein, we uncover an unusual red emission from a maleimide-based homopolymer (PM) in aqueous media, arising through CTE. Introduction of in vitro synthesized insulin amyloid fibrils (IAFs) directs this emissive polymer into an OFF-pathway, effectively suppressing its ON-state CTE. Fluorescence spectroscopic studies reveal that PM functions as a ratiometric probe for IAFs, where the β-sheet fibril architecture modulates CTE through supramolecular interactions and disrupted clustering. Complementary molecular dynamics (MD) simulations further demonstrate that the emission arises from a delicate balance of intra- and intermolecular interactions within polymer clusters, which become perturbed upon amyloid binding. Together, these findings provide mechanistic insight into CTE in nonconjugated systems and establish a foundation for developing water-soluble luminescent probes for selective amyloid detection and broader biomedical applications.