Low Surface Accessible Area NanoCoral TiO2 for the Reduction of Foreign Body Reaction During Implantation

Decoding the "Fingerprint" of Implant Materials: Insights into the Foreign Body Reaction

Foreign body reaction (FBR) is a prevalent yet often overlooked pathological phenomenon, particularly within the field of biomedical implantation. The presence of FBR poses a heavy burden on both the medical and socioeconomic systems. This review seeks to elucidate the protein "fingerprint" of implant materials, which is generated by the physiochemical properties of the implant materials themselves. In this review, the activity of macrophages, the formation of foreign body giant cells (FBGCs), and the development of fibrosis capsules in the context of FBR are introduced. Additionally, the relationship between various implant materials and FBR is elucidated in detail, as is an overview of the existing approaches and technologies employed to alleviate FBR. Finally, the significance of implant components (metallic materials and non-metallic materials), surface CHEMISTRY (charge and wettability), and physical characteristics (topography, roughness, and stiffness) in establishing the protein "fingerprint" of implant materials is also well documented. In conclusion, this review aims to emphasize the importance of FBR on implant materials and provides the current perspectives and approaches in developing implant materials with anti-FBR properties.

Fn-HMGB1 Adsorption Behavior Initiates Early Immune Recognition and Subsequent Osteoinduction of Biomaterials

Implantable biomaterials are widely used in bone tissue engineering, but little is still known about how they initiate early immune recognition and the initial dynamics. Herein, the early immune recognition and subsequent osteoinduction of biphasic calcium phosphate (BCP) after implantation to the protein adsorption behavior is attributed. By liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis, the biomaterial-related molecular patterns (BAMPs) formed after BCP implantation are mapped, dominated by the highly expressed extracellular matrix protein fibronectin (Fn) and the high mobility group box 1 (HMGB1). Molecular dynamics simulations show that Fn has the ability to bind more readily to the BCP surface than HMGB1. The preferential binding of Fn provides a higher adsorption energy for HMGB1. Furthermore, multiple hydrogen bonding sites between HMGB1 and Fn are demonstrated using a molecular docking approach. Ultimately, the formation of BAMPs through HMGB1 antagonist glycyrrhizic acid (GA), resulting in impaired immune recognition of myeloid differentiation factor 88 (MYD88) mediated dendritic cells (DCs) and macrophages (Mφs), as well as failed osteoinduction processes is obstructed. This study introduces a mechanism for early immune recognition of implant materials based on protein adsorption, providing perspectives for future design and application of tissue engineering materials.

Microenvironment-Regulating Drug Delivery Nanoparticles for Treating and Preventing Typical Biofilm-Induced Oral Diseases

The oral cavity comprises an environment full of microorganisms. Dysregulation of this microbial-cellular microenvironment will lead to a series of oral diseases, such as implant-associated infection caused by Staphylococcus aureus (S. aureus) biofilms and periodontitis initiated by Streptococcus oralis (S. oralis). In this study, a liposome-encapsulated indocyanine green (ICG) and rapamycin drug-delivery nanoparticle (ICG-rapamycin) is designed to treat and prevent two typical biofilm-induced oral diseases by regulating the microbial-cellular microenvironment. ICG-rapamycin elevates the reactive oxygen species (ROS) and temperature levels to facilitate photodynamic and photothermal mechanisms under near-infrared (NIR) laser irradiation for anti-bacteria. In addition, it prevents biofilm formation by promoting bacterial motility with increasing the ATP levels. The nanoparticles modulate the microbial-cellular interaction to reduce cellular inflammation and enhance bacterial clearance, which includes promoting the M2 polarization of macrophages, upregulating the anti-inflammatory factor TGF-β, and enhancing the bacterial phagocytosis of macrophages. Based on these findings, ICG-rapamycin is applied to implant-infected and periodontitis animal models to confirm the effects in vivo. This study demonstrates that ICG-rapamycin can treat and prevent biofilm-induced oral diseases by regulating the microbial-cellular microenvironment, thus providing a promising strategy for future clinical applications.

Enhanced Immunotherapy Based on Combining the Pro-phagocytosis and Anti-phagocytosis Checkpoint Blockade for Tumor Eradication

Compared to the activation of acquired immunity by the immune checkpoint blockade, the activation of innate immunity via anti-phagocytosis checkpoint blockade could significantly increase the beneficiary population of immunotherapy. However, the activation of innate immunity and the occurrence of phagocytosis are only accomplished when the interaction between pro-phagocytosis signals and anti-phagocytosis signals is realized. Herein, a versatile nanoplatform (DHMR) based on mesoporous silicon nanoparticles (MSNPs) has been constructed. Two drugs, doxorubicin, a chemotherapeutic drug which could initiate tumor cells to release pro-phagocytosis signals, and RRx-001, an immunoadjuvant that could effectively implement the anti-phagocytosis checkpoint blockade, were loaded in MSNPs. Further decoration of hyaluronic acid encapsulation endows DHMR with the function of tumor targeting and long circulation. Ultimately, the DHMR system could efficiently and accurately target tumor tissue, release the drugs in the tumor microenvironment, achieve the activation of innate immunity, and finally dramatically inhibit the growth and metastasis of tumor cells.