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Tightly sealed peri‐implant gingival tissue provides a barrier against oral bacterial invasion, protecting the alveolar bone and maintaining long‐term implant survival. To investigate if zinc can enhance the integration between peri‐implant gingival tissue and abutment surface, we herein present novel zinc/chitosan/gelatin (Zn/CS/Gel) coatings prepared using the electrophoretic deposition (EPD) technique. The effect of these coatings on human gingival fibroblasts (hGFs) was investigated by culturing these cells on top of the EPD coatings. Surface characterization demonstrated that Zn2+ were released in a sustained and pH‐responsive manner. The preclinical cell culture evaluation of these coatings indicated that the zinc‐containing coatings enhanced cell migration, adhesion and collagen secretion of hGFs. Moreover, the zinc‐containing coatings exhibited antibacterial efficacy by inhibiting the growth of Porphyromonas gingivalis and reducing attachment of Staphylococcus aureus. Notably, zinc‐free CS/Gel coatings prevented attachment of P. gingivalis as well. The coatings were also shown to be cytocompatible with epithelial cells and osteoblasts, which are other relevant cell types which surround dental implants after clinical placement. Based on our findings, it can be concluded that Zn‐containing coatings hold promise to enhance the adhesion of gingival tissue to the implant surface, which may potentially contribute to the formation of a robust peri‐implant soft sealing counteracting bacterial invasion. [ABSTRACT FROM AUTHOR]

Star-shaped poly(ethylene glycol) (PEG) chain termini were functionalized with alendronate to create transient networks with reversible crosslinks upon addition of calcium ions. The gelation ability of alendronate-functionalized PEG was greatly dependent on the number of arms and arm molecular weight. After mixing polymer and calcium solutions, the formed hydrogels could be cut and then brought back together without any visible interface. After 2 minutes of contact, their connection was strong enough to allow for stretching without tearing through the previous fracture surface. Oscillatory rheology showed that the hydrogels recovered between 70 and 100% of the original storage and loss modulus after rupture. Frequency sweep measurements revealed a liquid-like behavior at lower frequencies and solid-like at high frequencies. Shifting frequency curves obtained at different calcium and polymer concentrations, all data collapsed in a single common master curve. This time-concentration superposition reveals a common relaxation mechanism intrinsically connected to the calcium-bisphosphonate complexation equilibrium.

Treating bone infections with common antibiotics is challenging, since pathogens like Staphylococcus aureus can reside inside macrophages. To target these intracellular bacteria, we have proposed nanoparticles (NPs) as drug carriers. This study aims to investigate the efficacy of hydroxyapatite and gelatin NPs, selected in view of their bone mimicry and potential for targeted delivery, as carriers for the antibacterial agents zinc and vancomycin. Therefore, two distinct NPs are fabricated: zinc-doped hydroxyapatite (ZnHA) and vancomycin-loaded gelatin (VGel) NPs. The NPs are characterized based on morphology, size, chemical composition, cellular internalization, and intracellular bactericidal efficacy. Specifically, the intracellular bactericidal efficacy is tested using a validated coculture model of human THP-1 derived macrophages and phagocytosed S. aureus bacteria. Scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy (FTIR) results show that the spherical NPs are synthesized successfully. These NPs are internalized by THP-1 cells and show >75% colocalization with lysosomes without compromising the viability of the THP-1 cells. Both ZnHA and VGel NPs substantially reduce the intracellular survival of S. aureus compared to the direct addition of dissolved zinc and vancomycin. Concluding, our NPs are highly effective drug delivery vehicles to kill intracellular S. aureus , which stress the potential of these NPs for future clinical translation. [ABSTRACT FROM AUTHOR]

Most bone metastases are caused by primary breast or prostate cancer cells settling in the bone microenvironment, affecting normal bone physiology and function and reducing 5‐year survival rates to 10% and 6%, respectively. To expedite clinical availability of novel and effective bone metastases treatments, reliable and predictive in vitro models are urgently required to screen for novel therapies as current in vitro 2D planar mono‐culture models do not accurately predict the clinical efficacy. We herein engineered a novel human in vitro 3D co‐culture model based on spheroids to study dynamic cellular quantities of (breast or prostate) cancer cells and human bone marrow stromal cells and screen chemotherapeutic efficacy and specificity of the common anticancer drug cisplatin. Bone metastatic spheroids (BMSs) were formed rapidly within 24 h, while the morphology of breast versus prostate cancer BMS differed in terms of size and circularity upon prolonged culture periods. Prestaining cell types prior to BMS formation enabled confocal imaging and quantitative image analysis of in‐spheroid cellular dynamics for up to 7 days of BMS culture. We found that cancer cells in BMS proliferated faster and were less susceptible to cisplatin treatment compared to 2D control cultures. Based on these findings and the versatility of our methodology, BMS represent a feasible 3D in vitro model for screening of new bone cancer metastases therapies. [ABSTRACT FROM AUTHOR]

Biomaterials are currently applied in increasingly complex areas such as tissue engineering, bioprinting and regenerative medicine. To this end, challenging combinations of biomaterial properties are required which usually cannot be met by conventional biomaterials. Since the early 2000s, several new concepts have been proposed to render biomaterials self-healing in order to improve the functionality of traditional biomaterials in terms of their mechanical, handling and biological properties. This presentation will provide a comprehensive overview of the field of self-healing biomaterials, ranging from self-healing of capsule-filled dental fillers and bone cements, to the self-healing behavior of modern injectable hydrogels used in regenerative medicine. More specifically, the presentation will highlight why self-healing properties of biomaterials are crucial for minimally invasive injection into the human body and achieve successful tissue regeneration.