Enhanced osteogenic and antibacterial properties of polyetheretherketone by ultraviolet-initiated grafting polymerization of a gelatin methacryloyl/epsilon-poly-L-lysine/laponite hydrogel coating

Enhanced osteogenic and bactericidal performance of premixed calcium phosphate cement with photocrosslinked alginate thin film

The increasing prevalence of implant-associated infections (IAI) in orthopedics remains a public health challenge. Calcium phosphates (CaPs) are critical biomaterials in dental treatments and bone regeneration. It is highly desirable to endow CaPs with antibacterial properties. To achieve this purpose, we developed a photocrosslinked methacrylated alginate co-calcium phosphate cement (PMA-co-PCPC) with antibacterial properties, using α-tricalcium phosphate (α-TCP) powders with 16% amorphous contents as solid phase, liquid phases containing CuCl2 and SrCl2 as an inhibitor, and CaCl2 as an activator to construct PCPC. When CaCl2 started to activate the hydration reaction, Sr2+ or Cu2+ ions were exchanged with Ca2+, and α-TCP dissolution was restarted and gradually hydrated to form calcium-deficient hydroxyapatite (CDHA). PMA was added to crosslink with Cu/Sr ions and form gel-layer-wrapped hydrated CDHA. This study explored the binding mechanism of PMA and PCPC and the ion release rule of Ca2+ → Sr2+/Cu2+, optimized the construction of several antibacterial PMA-co-PCPC materials, and analyzed the physical, chemical, and biological properties. Because of the combined effect of Cu and Sr ions, the scaffold exhibited a potential antibacterial activity, promoting bone formation and vascular regeneration. This work provides a basis for designing antibacterial calcium phosphate biomaterials with controllable treatment, which is an important characteristic for preventing IAI of biomaterials.

Hydrogel Coatings of Implants for Pathological Bone Repair

Hydrogels are well-suited for biomedical applications due to their numerous advantages, such as excellent bioactivity, versatile physical and chemical properties, and effective drug delivery capabilities. Recently, hydrogel coatings have developed to functionalize bone implants which are biologically inert and cannot withstand the complex bone tissue repair microenvironment. These coatings have shown promise in addressing unique and pressing medical needs. This review begins with the major functionalized performance and interfacial bonding strategy of hydrogel coatings, with a focus on the novel external field response properties of the hydrogel. Recent advances in the fabrication strategies of hydrogel coatings and their use in the treatment of pathologic bone regeneration are highlighted. Finally, challenges and emerging trends in the evolution and application of physiological environment-responsive and external electric field-responsive hydrogel coatings for bone implants are discussed.

Multifunctional Hydrogel Enhances Inflammatory Control, Antimicrobial Activity, and Oxygenation to Promote Healing in Infectious Wounds

Chronic infected wounds often fail to heal through normal repair mechanisms, and the persistent response of reactive oxygen species (ROS) and inflammation is a major contributing factor to the difficulty in their healing. In this context, we developed an ROS-responsive injectable hydrogel. This hydrogel is composed of ε-polylysine grafted (EPL) with caffeic acid (CA) and hyaluronic acid (HA) grafted with phenylboronic acid (PBA). Before the gelation process, a mixture CaO2@Cur-PDA (CCP) consisting of calcium peroxide (CaO2) coated with polydopamine (PDA) and curcumin (Cur) is embedded into the hydrogel. Under the conditions of chronic refractory wound environments, the hydrogel gradually dissociates. HA mimics the function of the extracellular matrix, while the released caffeic acid-grafted ε-polylysine (CE) effectively eliminates bacteria in the wound vicinity. Additionally, released CA also clears ROS and influences macrophage polarization. Subsequently, CCP further decomposes, releasing Cur, which promotes angiogenesis. This multifunctional hydrogel accelerates the repair of diabetic skin wounds infected with Staphylococcus aureus in vivo and holds promise as a candidate dressing for the healing of chronic refractory wounds.

Fabrication of a 3D bioprinting model for posterior capsule opacification using GelMA and PLMA hydrogel-coated resin

Posterior capsule opacification (PCO) remains the predominant complication following cataract surgery, significantly impairing visual function restoration. In this study, we developed a PCO model that closely mimics the anatomical structure of the crystalline lens capsule post-surgery. The model incorporated a threaded structure for accurate positioning and observation, allowing for opening and closing. Utilizing 3D printing technology, a stable external support system was created using resin material consisting of a rigid, hollow base and cover. To replicate the lens capsule structure, a thin hydrogel coating was applied to the resin scaffold. The biocompatibility and impact on cellular functionality of various hydrogel compositions were assessed through an array of staining techniques, including calcein-AM/PI staining, rhodamine staining, BODIPY-C11 staining and EdU staining in conjunction with transwell assays. Additionally, the PCO model was utilized to investigate the effects of eight drugs with anti-inflammatory and anti-proliferative properties, including 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), THZ1, sorbinil, 4-octyl itaconate (4-OI), xanthohumol, zebularine, rapamycin and caffeic acid phenethyl ester, on human lens epithelial cells (HLECs). Confocal microscopy facilitated comprehensive imaging of the PCO model. The results demonstrated that the GelMA 60 5% + PLMA 2% composite hydrogel exhibited superior biocompatibility and minimal lipid peroxidation levels among the tested hydrogels. Moreover, compared to using hydrogel as the material for 3D printing the entire model, applying surface hydrogel spin coating with parameters of 2000 rpm × 2 on the resin-based 3D printed base yielded a more uniform cell distribution and reduced apoptosis. Furthermore, rapamycin, 4-OI and AICAR demonstrated potent antiproliferative effects in the drug intervention study. Confocal microscopy imaging revealed a uniform distribution of HLECs along the anatomical structure of the crystalline lens capsule within the PCO model, showcasing robust cell viability and regular morphology. In conclusion, the PCO model provides a valuable experimental platform for studying PCO pathogenesis and exploring potential therapeutic interventions.

Laponite for biomedical applications: An ophthalmological perspective

Clay minerals have been applied in biomedicine for thousands of years. Laponite is a nanostructured synthetic clay with the capacity to retain and progressively release drugs. In recent years there has been a resurgence of interest in Laponite application in various biomedical areas. This is the first paper to review the potential biomedical applications of Laponite in ophthalmology. The introduction briefly covers the physical, chemical, rheological, and biocompatibility features of different routes of administration. After that, emphasis is placed on 1) drug delivery for antibiotics, anti-inflammatories, growth factors, other proteins, and cancer treatment; 2) bleeding prevention or treatment; and 3) tissue engineering through regenerative medicine using scaffolds in intraocular and extraocular tissue. Although most scientific research is not performed on the eye, both the findings and the new treatments resulting from that research are potentially applicable in ophthalmology since many of the drugs used are the same, the tissue evaluated in vitro or in vivo is also present in the eye, and the pathologies treated also occur in the eye. Finally, future prospects for this emerging field are discussed.