Exogenous Protein Delivery of Ionic Liquid-Mediated HMGB1 Coating on Titanium Implants

Biological Effects of New Titanium Surface Coatings Based on Ionic Liquids and HMGB1: A Cellular and Molecular Characterization in Lewis Rats

High Mobility Group Box 1 (HMGB1) is a redox-sensitive molecule that plays dual roles in tissue healing and inflammation. We previously demonstrated that HMGB1 is stable when anchored by a well-characterized imidazolium-based ionic liquid (IonL), which serves as a delivery vehicle for exogenous HMGB1 to the site of injury and prevents denaturation from surface adherence. However, HMGB1 exists in different isoforms [fully reduced HMGB1 (FR), a recombinant version of FR resistant to oxidation (3S), disulfide HMGB1 (DS), and inactive sulfonyl HMGB1(SO)] that have distinct biological functions in health and disease. Thus, the goal of this study was to evaluate the effects of different recombinant HMGB1 isoforms on the host response using a rat subcutaneous implantation model. A total of 12 male Lewis rats (12-15 weeks) were implanted with titanium discs containing different treatments (n = 3/time point; Ti, Ti-IonL, Ti-IonL-DS, Ti-IonL-FR, and Ti-IonL-3S) and assessed at 2 and 14 days. Histological (H&E and Goldner trichrome staining), immunohistochemistry, and molecular analyses (qPCR) of surrounding implant tissues were employed for analysis of inflammatory cells, HMGB1 receptors, and healing markers. Ti-IonL-DS samples resulted in the thickest capsule formation, increased pro-inflammatory, and decreased anti-inflammatory cells, while Ti-IonL-3S samples demonstrated suitable tissue healing similar to uncoated Ti discs, as well as an upregulation of anti-inflammatory cells at 14 days compared to all other treatments. Thus, results from this study demonstrated that Ti-IonL-3S are safe alternatives for Ti biomaterials. Future studies are necessary to investigate the healing potential of Ti-IonL-3S in osseointegration scenarios.

Fiber Optic Localized Surface Plasmon Resonance Sensor Based on Carboxymethylated Dextran Modified Gold Nanoparticles Surface for High Mobility Group Box 1 (HMGB1) Analysis

Rapid, sensitive, and reliable detection of high mobility group box 1 (HMGB1) is essential for medical and diagnostic applications due to its important role as a biomarker of chronic inflammation. Here, we report a facile method for the detection of HMGB1 using carboxymethyl dextran (CM-dextran) as a bridge molecule modified on the surface of gold nanoparticles combined with a fiber optic localized surface plasmon resonance (FOLSPR) biosensor. Under optimal conditions, the results showed that the FOLSPR sensor detected HMGB1 with a wide linear range (10^-10 to 10^-6 g/mL), fast response (less than 10 min), and a low detection limit of 43.4 pg/mL (1.7 pM) and high correlation coefficient values (>0.9928). Furthermore, the accurate quantification and reliable validation of kinetic binding events measured by the currently working biosensors are comparable to surface plasmon resonance sensing systems, providing new insights into direct biomarker detection for clinical applications.