Silk fibroin (SF) is a protein-based biomacromolecule with excellent biocompatibility, biodegradability and low immunogenicity. The development of SF-based nanoparticles for drug delivery have received considerable attention due to high binding capacity for various drugs, controlled drug release properties and mild preparation conditions. By adjusting the particle size, the chemical structure and properties, the modified or recombinant SF-based nanoparticles can be designed to improve the therapeutic efficiency of drugs encapsulated into these nanoparticles. Therefore, they can be used to deliver small molecule drugs (e.g., anti-cancer drugs), protein and growth factor drugs, gene drugs, etc. This paper reviews recent progress on SF-based nanoparticles, including chemical structure, properties, and preparation methods. In addition, the applications of SF-based nanoparticles as carriers for therapeutic drugs are also reviewed.

In order to enhance the bioavailability of poorly water-soluble curcumin, solution-enhanced dispersion by supercritical carbon dioxide (CO 2 ) (SEDS) was employed to prepare curcumin nanoparticles for the first time. A 2 4 full factorial experiment was designed to determine optimal processing parameters and their influence on the size of the curcumin nanoparticles. Particle size was demonstrated to increase with increased temperature or flow rate of the solution, or with decreased precipitation pressure, under processing conditions with different parameters considered. The single effect of the concentration of the solution on particle size was not significant. Curcumin nanoparticles with a spherical shape and the smallest mean particle size of 325 nm were obtained when the following optimal processing conditions were adopted: P =20 MPa, T =35°C, flow rate of solution =0.5 mL·min −1 , concentration of solution =0.5%. Fourier transform infrared (FTIR) spectroscopy measurement revealed that the chemical composition of curcumin basically remained unchanged. Nevertheless, X-ray powder diffraction (XRPD) and thermal analysis indicated that the crystalline state of the original curcumin decreased after the SEDS process. The solubility and dissolution rate of the curcumin nanoparticles were found to be higher than that of the original curcumin powder (approximately 1.4 μg/mL vs 0.2 μg/mL in 180 minutes). This study revealed that supercritical CO 2 technologies had a great potential in fabricating nanoparticles and improving the bioavailability of poorly water-soluble drugs.

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extrusion bioprinting is mainly used for constructing volumetric structures in a layer-wise manner. [5] Although the layerby-layer bioprinting method is functional in majority of the cases, [6] there are limitations associated with creating anisotropic tissues, such as muscle fibers [7,8] and nerve fibers [9] that heavily rely on cellular alignment for their physiologies. Therefore, developing a versatile strategy that allows convenient 3D bioprinting synergized with simultaneous generation of structural anisotropy is essential for these applications.Numerous studies have shown that porous hydrogel scaffolds can potentially enhance cell spreading and proliferation. [10,11] In particular, ice-templating, one of the most widely utilized techniques for the fabrication of materials with anisotropic microchannels, allows control over pore morphologies by controlling directional ice formation in a suspension of solute(s). [12][13][14][15] During the freezing process, ice crystals form and propagate through a set direction within the biomaterial solution. When the construct cross-links and thaws, the melted ice crystals form interconnected anisotropic microchannels within the scaffold. Importantly, previous studies have clearly demonstrated that the presence of anisotropic microchannels enhances Due to the poor mechanical properties of many hydrogel bioinks, conventional 3D extrusion bioprinting is usually conducted based on the X-Y plane, where the deposited layers are stacked in the Z-direction with or without the support of prior layers. Herein, a technique is reported, taking advantage of a cryoprotective bioink to enable direct extrusion bioprinting in the vertical direction in the presence of cells, using a freezing plate with precise temperature control. Of interest, vertical 3D cryo-bioprinting concurrently allows the user to create freestanding filamentous constructs containing interconnected, anisotropic microchannels featuring gradient sizes aligned in the vertical direction, also associated with enhanced mechanical performances. Skeletal myoblasts within the 3D-cryo-bioprinted hydrogel constructs show enhanced cell viability, spreading, and alignment, compared to the same cells in the standard hydrogel constructs. This method is further extended to a multimaterial format, finding potential applications in interface tissue engineering, such as creation of the muscle-tendon unit and the muscle-microvascular unit. The unique vertical 3D cryo-bioprinting technique presented here suggests improvements in robustness and versatility to engineer certain tissue types especially those anisotropic in nature, and may extend broad utilities in tissue engineering, regenerative medicine, drug discovery, and personalized therapeutics.

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Tumor lineage plasticity is emerging as a critical mechanism of therapeutic resistance and tumor relapse. Highly plastic tumor cells can undergo phenotypic switching to a drug-tolerant state to avoid drug toxicity. Here, we investigate the transmembrane tight junction protein Claudin6 (CLDN6) as a therapeutic target related to lineage plasticity for hepatocellular carcinoma (HCC). CLDN6 was highly expressed in embryonic stem cells but markedly decreased in normal tissues. Reactivation of CLDN6 was frequently observed in HCC tumor tissues as well as in premalignant lesions. Functional assays indicated that CLDN6 is not only a tumor-associated antigen but also conferred strong oncogenic effects in HCC. Overexpression of CLDN6 induced phenotypic shift of HCC cells from hepatic lineage to biliary lineage, which was more refractory to sorafenib treatment. The enhanced tumor lineage plasticity and cellular identity change were potentially induced by the CLDN6/TJP2 (tight junction protein 2)/YAP1 (Yes-associated protein 1) interacting axis and further activation of the Hippo signaling pathway. A de novo anti-CLDN6 monoclonal antibody conjugated with cytotoxic agent (Mertansine) DM1 (CLDN6-DM1) was developed. Preclinical data on both HCC cell lines and primary tumors showed the potent antitumor efficiency of CLDN6-DM1 as a single agent or in combination with sorafenib in HCC treatment.

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The development of more effective cancer therapeutic strategies are still critically required. The maximization of the therapeutic effect in combination with avoiding the severe side effects on normal tissues when using chemotherapy drugs is still an urgent problem that requires improvements urgently. Here we provide implantable and controllable drug-release that utilises silk fibroin (SF) as a nanofibrous drug delivery system (DDS) for cancer treatment. A nanofibrous structure with controllable fibre diameter (<100 nm) was produced. The drug release rate of the SF DDS was controlled by applying a post-treatment process. In vitro anti-cancer (HCT116) results indicated that curcumin (CM)-SF nanofibrous matrix had a superior anti-cancer potential when the concentration was >5 μg/mL. The mechanism could be explained by the cell cycle being held in the S phase. The toxic effect on normal cells (NCM460) was minimized by using a treatment concentration range (5-20 μg/mL). Implantation of this DDS into the tumour site inhibited the growth of solid tumour; this offers an alternative approach for novel cancer therapy.