A pH-response chemotherapy synergistic photothermal therapy for tumor suppression and bone regeneration by mussel-inspired Mg implant

Application of advanced biomaterials in photothermal therapy for malignant bone tumors

Malignant bone tumors are characterized by severe disability rate, mortality rate, and heavy recurrence rate owing to the complex pathogenesis and insidious disease progression, which seriously affect the terminal quality of patients' lives. Photothermal therapy (PTT) has emerged as an attractive adjunctive treatment offering prominent hyperthermal therapeutic effects to enhance the effectiveness of surgical treatment and avoid recurrence. Simultaneously, various advanced biomaterials with photothermal capacity are currently created to address malignant bone tumors, performing distinctive biological functions, including nanomaterials, bioceramics (BC), polymers, and hydrogels et al. Furthermore, PTT-related combination therapeutic strategies can provide more significant curative benefits by reducing drug toxicity, improving tumor-killing efficiency, stimulating anti-cancer immunity, and improving immune sensitivity relative to monotherapy, even in complex tumor microenvironments (TME). This review summarizes the current advanced biomaterials applicable in PTT and relevant combination therapies on malignant bone tumors for the first time. The multiple choices of advanced biomaterials, treatment methods, and new prospects for future research in treating malignant bone tumors with PTT are generalized to provide guidance. Malignant bone tumors seriously affect the terminal quality of patients' lives. Photothermal therapy (PTT) has emerged as an attractive adjunctive treatment enhancing the effectiveness of surgical treatment and avoiding recurrence. In this review, advanced biomaterials applicable in the PTT of malignant bone tumors and their distinctive biological functions are comprehensively summarized for the first time. Simultaneously, multiple PTT-related combination therapeutic strategies are classified to optimize practical clinical issues, contributing to the selection of biomaterials, therapeutic alternatives, and research perspectives for the adjuvant treatment of malignant bone tumors with PTT in the future.

Synergetic regulation of cancer cells and exhausted T cells to fight cold tumors with a fluorinated EGCG-based nanocomplex

Immune therapy that targets PD-L1 (programmed cell death-ligand 1) is attractive to augment immune response by breaking the programmed cell death-1 (PD-1)/PD-L1 axis. However, T cell exhaustion associated with insufficient T cells infiltration may diminish the efficacy of cancer therapy. Here, we report a novel delivery system of FEGCG/FPEI@siTOX composed of fluorinated EGCG (FEGCG) and fluorinated polyethyleneimine (FPEI) for delivery of small interfering RNA anti-TOX (thymus high mobility group box protein, TOX) to treat tumor and metastasis. In this way, the reduction in PD-L1 expression by FEGCG can promote T-cell function, while inhibition of TOX expression with siTOX can alleviate T-cell exhaustion. FPEI are designed to deliver siRNA with high efficiency and low toxicity compared to classical PEI. Integrating FEGCG, FPEI and siTOX into such a novel system resulted in excellent anti-tumor and antimetastatic effects. It is a promising delivery system and potential strategy for the treatment of "cold" tumors.

Electro-Responsive Conductive Blended Hydrogel Patch

The proposed electro-responsive hydrogel has great benefit for transdermal drug delivery system (TDDS) applications. To improve the physical or chemical properties of hydrogels, a number of researchers have previously studied the mixing efficiencies of the blended hydrogels. However, few studies have focused on improving the electrical conductivity and drug delivery of the hydrogels. We developed a conductive blended hydrogel by mixing alginate with gelatin methacrylate (GelMA) and silver nanowire (AgNW). We demonstrated that and the tensile strength of blended hydrogels were increased by a factor of 1.8 by blending GelMA and the electrical conductivity was enhanced by a factor of 18 by the addition of AgNW. Furthermore, the GelMA-alginate-AgNW (Gel-Alg-AgNW) blended hydrogel patch enabled on-off controllable drug release, indicating 57% doxorubicin release in response to electrical stimulation (ES) application. Therefore, this electro-responsive blended hydrogel patch could be useful for smart drug delivery applications.

Regulable Polyelectrolyte-Surfactant Complex for Antibacterial Biomedical Catheter Coating via a Readily Scalable Route

Constructing multifunctional surfaces is one of the practical approaches to address catheter-related multiple complications but is generally time-consuming and substrate-dependent. Herein, a novel anti-adhesion, antibacterial, low friction, and robustness coating on medical catheters are developed via a universal and readily scalable method based on a regulable polyelectrolyte surfactant complex. The complex is rapidly assembled in one step by electrostatic and hydrophobic interactions between organosilicon quaternary ammonium surfactant (N⁺ _Si ) and adjustable polyelectrolyte with cross-linkable, anti-adhesive, and anionic groups. The alcohol-soluble feature of the complex is conducive to the rapid formation of coatings on any medical device with arbitrary shapes via dip coating. Different from the conventional polyelectrolyte-surfactant complex coating, the regulated complex coating with nonleaching mode could be stable in harsh conditions (high concentration salt solution, organic reagents, etc.) because of the cross-linked structure while improving the biocompatibility and reducing the adhesion of various bacteria, proteins, and blood cells. The coated catheter exhibits good antibacterial infection in vitro and in vivo, owing to the synergistic effect of N⁺ _Si and zwitterionic groups. Therefore, the rationally designed complex supplies a facile coating approach for the potential development in combating multiple complications of the medical catheter.

Recent advances in regenerative biomaterials

Nowadays, biomaterials have evolved from the inert supports or functional substitutes to the bioactive materials able to trigger or promote the regenerative potential of tissues. The interdisciplinary progress has broadened the definition of 'biomaterials', and a typical new insight is the concept of tissue induction biomaterials. The term 'regenerative biomaterials' and thus the contents of this article are relevant to yet beyond tissue induction biomaterials. This review summarizes the recent progress of medical materials including metals, ceramics, hydrogels, other polymers and bio-derived materials. As the application aspects are concerned, this article introduces regenerative biomaterials for bone and cartilage regeneration, cardiovascular repair, 3D bioprinting, wound healing and medical cosmetology. Cell-biomaterial interactions are highlighted. Since the global pandemic of coronavirus disease 2019, the review particularly mentions biomaterials for public health emergency. In the last section, perspectives are suggested: (i) creation of new materials is the source of innovation; (ii) modification of existing materials is an effective strategy for performance improvement; (iii) biomaterial degradation and tissue regeneration are required to be harmonious with each other; (iv) host responses can significantly influence the clinical outcomes; (v) the long-term outcomes should be paid more attention to; (vi) the noninvasive approaches for monitoring in vivo dynamic evolution are required to be developed; (vii) public health emergencies call for more research and development of biomaterials; and (viii) clinical translation needs to be pushed forward in a full-chain way. In the future, more new insights are expected to be shed into the brilliant field-regenerative biomaterials.

A hydrophobic layer prepared by cyclic grafting of polydimethylsiloxane on magnesium: improved corrosion resistance and biocompatibility

Magnesium and its alloys have been widely studied as absorbable coronary stent materials. However, the rapid corrosion rate in the intravascular environment inhibits the application of magnesium-based stents. In order to endow magnesium-based stent with appropriate degradation rate and biocompatibility, a hydrophobic layer was constructed by in situ cyclic grafting 4,4'-diphenylmethane diisocyanate and aminopropyl-terminated polydimethylsiloxane on pure magnesium. SEM-EDS, X-ray photoelectron spectroscopy and water contact angle were detected to analyze the chemical composition of the layer. The amino groups were confirmed to be introduced on the surface which provide a platform for subsequent modification. The contact angle value of the modified surface is 132.1°, indicating a hydrophilic surface. The electrochemical measurements and immersion tests demonstrated that the hydrophobic layer significantly improved the anti-corrosion ability of the substrate. Besides, the biocompatibility of the hydrophobic surface was examined by platelet adhesion, cytocompatibility in vitro and subcutaneous implantation in vivo. Immunological and histological results indicated that the hydrophobic layer had excellent biocompatibility. Therefore, the presented study might be a promising method for the surface modification of biomedical magnesium-based stent.

Mussel-Inspired Polydopamine-Based Multilayered Coatings for Enhanced Bone Formation

Repairing bone defects remains a challenge in clinical practice and the application of artificial scaffolds can enhance local bone formation, but the function of unmodified scaffolds is limited. Considering different application scenarios, the scaffolds should be multifunctionalized to meet specific demands. Inspired by the superior adhesive property of mussels, polydopamine (PDA) has attracted extensive attention due to its universal capacity to assemble on all biomaterials and promote further adsorption of multiple external components to form PDA-based multilayered coatings with multifunctional property, which can induce synergistic enhancement of new bone formation, such as immunomodulation, angiogenesis, antibiosis and antitumor property. This review will summarize mussel-inspired PDA-based multilayered coatings for enhanced bone formation, including formation mechanism and biofunction of PDA coating, as well as different functional components. The synergistic enhancement of multiple functions for better bone formation will also be discussed. This review will inspire the design and fabrication of PDA-based multilayered coatings for different application scenarios and promote deeper understanding of their effect on bone formation, but more efforts should be made to achieve clinical translation. On this basis, we present a critical conclusion, and forecast the prospects of PDA-based multilayered coatings for bone regeneration.