Inspired by biological systems, we report a supramolecular polymer-colloidal hydrogel (SPCH) composed of 98 wt % water that can be readily drawn into uniform (∼6-µm thick) "supramolecular fibers" at room temperature. Functionalized polymer-grafted silica nanoparticles, a semicrystalline hydroxyethyl cellulose derivative, and cucurbit[8]uril undergo aqueous self-assembly at multiple length scales to form the SPCH facilitated by host-guest interactions at the molecular level and nanofibril formation at colloidal-length scale. The fibers exhibit a unique combination of stiffness and high damping capacity (60-70%), the latter exceeding that of even biological silks and cellulose-based viscose rayon. The remarkable damping performance of the hierarchically structured fibers is proposed to arise from the complex combination and interactions of "hard" and "soft" phases within the SPCH and its constituents. SPCH represents a class of hybrid supramolecular composites, opening a window into fiber technology through low-energy manufacturing. supramolecular fiber | hydrogel | self-assembly | damping | spider silk I n nature, spiders spin silk fibers with superb properties at ambient temperatures and pressures (1, 2). We have yet to mimic such an elegant process. Conventionally, synthetic fibers are manufactured through a variety of spinning techniques, including wet, dry, gel, and electrospinning (3). Such approaches to generate fibers are limited by high energy input, laborious procedures, and intensive use of organic solvents. Supramolecular pathways enable the formation of filamentous soft materials that are showing promise in biomedical applications (4-6), such as cell culture (7-9) and tissue engineering (10). However, such materials are constrained by the length scale (submicrometer level) (11-13), energy intake during production (9), and complex design of assembly units (14).Here, we report drawing supramolecular fibers of arbitrary length from a dynamic supramolecular polymer-colloidal hydrogel (SPCH) at room temperature (Movie S1). The components consist of methyl viologen (MV)-functionalized polymer-grafted silica nanoparticles (P1), a semicrystalline polymer in the form of a hydroxyethyl cellulose derivative (H1), and cucurbit[8]uril (CB[8]) as illustrated in Fig. 1. The macrocycle CB[8] is capable of simultaneously encapsulating two guests within its cavity, forming a stable yet dynamic ternary complex, and has been exploited as a supramolecular "handcuff" to physical cross-link functional polymers (15-18). Introducing shape-persistent nanoparticles into the supramolecular hydrogel system allows for modification of the local gel structures at the colloidal-length scale, resulting in assemblies with unique emergent properties (19). The hierarchical nature of the SPCH is presented, where the hydrogel is composed of nanoscale fibrillar structures. The self-assembled SPCH composite exhibits great elasticity at a remarkably high water content (98%), showing a low-energy manufacturing process for fibers from natural, ...

Effective reversal of tumor immunosuppression is of critical importance in cancer therapy. A multifunctional delivery vector that can effectively deliver CRISPR‐Cas9 plasmid for β‐catenin knockout to reverse tumor immunosuppression is constructed. The multi‐functionalized delivery vector is decorated with aptamer‐conjugated hyaluronic acid and peptide‐conjugated hyaluronic acid to combine the tumor cell/nuclear targeting function of AS1411 with the cell penetrating/nuclear translocation function of TAT‐NLS. Due to the significantly enhanced plasmid enrichment in malignant cell nuclei, the genome editing system can induce effective β‐catenin knockout and suppress Wnt/β‐catenin pathway, resulting in notably downregulated proteins involved in tumor progression and immunosuppression. Programmed death‐ligand 1 (PD‐L1) downregulation in edited tumor cells not only releases the PD‐1/PD‐L1 brake to improve the cancer killing capability of CD8+ T cells, but also enhances antitumor immune responses of immune cells. This provides a facile strategy to reverse tumor immunosuppression and to restore immunosurveillance and activate anti‐tumor immunity.

Spider silk is a fascinating material, combining high strength and elasticity that outperforms most synthetic fibers. Another intriguing feature of spider silk is its ability to "supercontract," shrinking up to 50% when exposed to water. This is likely on account of the entropy-driven recoiling of secondary structured proteins when water penetrates the spider silk. In contrast, humidity-driven contraction in synthetic fibers is difficult to achieve. Here, inspired by the spider silk model, a supercontractile fiber (SCF), which contracts up to 50% of its original length at high humidity, comparable to spider silk, is reported. The fiber exhibits up to 300% uptake of water by volume, confirmed via environmental scanning electron microscopy. Interestingly, the SCF exhibits tunable mechanical properties by varying humidity, which is reflected by the prolonged failure strain and the reversible damping capacity. This smart supramolecular fiber material provides a new opportunity of fabricating biomimetic muscle for diverse applications.

To enhance the treatment efficiency in tumor therapy, we developed a tumor-targeting protein-based delivery system, DOX&ICG@BSA-KALA/Apt, to efficiently integrate multimodal therapy with tumor imaging and realize synchronous photodynamic therapy/photothermal therapy/ chemotherapy. In the delivery system, a chemotherapeutic drug (doxorubicin, DOX) and an optotheranostic agent (indocyanine green, ICG) were co-loaded in bovine serum albumin (BSA) via a hydrophobic-interaction-induced selfassembly to form stable DOX&ICG@BSA nanoparticles. After the decoration of a surface layer composed of a tumortargeting aptamer (AS1411) and a cell-penetrating peptide (KALA), the obtained DOX&ICG@BSA-KALA/Apt nanoparticles exhibit a significantly improved multimodal cancer therapeutic efficiency due to the enhanced cancer cellular uptake mediated by AS1411 and KALA. In vitro and in vivo studies show that the multimodal theranostic system can efficiently inhibit tumor growth. In addition, the near-infrared fluorescent/photothermal dual-mode imaging enables accurate visualization of the therapeutic action in tumor sites. This study provides a facile strategy to construct self-assembled multimodal theranostic systems, and the functional protein-based theranostic system prepared holds great promise in multimodal cancer therapeutics.

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