Highly interconnected macroporous MBG/PLGA scaffolds with enhanced mechanical and biological properties via green foaming strategy

Honeycomb-like biomimetic scaffold by functionalized antibacterial hydrogel and biodegradable porous Mg alloy for osteochondral regeneration

Introduction: Osteochondral repair poses a significant challenge due to its unique pathological mechanisms and complex repair processes, particularly in bacterial tissue conditions resulting from open injuries, infections, and surgical contamination. This study introduces a biomimetic honeycomb-like scaffold (Zn-AlgMA@Mg) designed for osteochondral repair. The scaffold consists of a dicalcium phosphate dihydrate (DCPD)-coated porous magnesium scaffold (DCPD Mg) embedded within a dual crosslinked sodium alginate hydrogel (Zn-AlgMA). This combination aims to synergistically exert antibacterial and osteochondral integrated repair properties. Methods: The Zn-AlgMA@Mg scaffold was fabricated by coating porous magnesium scaffolds with DCPD and embedding them within a dual crosslinked sodium alginate hydrogel. The structural and mechanical properties of the DCPD Mg scaffold were characterized using scanning electron microscopy (SEM) and mechanical testing. The microstructural features and hydrophilicity of Zn-AlgMA were assessed. In vitro studies were conducted to evaluate the controlled release of magnesium and zinc ions, as well as the scaffold's osteogenic, chondrogenic, and antibacterial properties. Proteomic analysis was performed to elucidate the mechanism of osteochondral integrated repair. In vivo efficacy was evaluated using a rabbit full-thickness osteochondral defect model, with micro-CT evaluation, quantitative analysis, and histological staining (hematoxylin-eosin, Safranin-O, and Masson's trichrome). Results: The DCPD Mg scaffold exhibited a uniform porous structure and superior mechanical properties. The Zn-AlgMA hydrogel displayed consistent microstructural features and enhanced hydrophilicity. The Zn-AlgMA@Mg scaffold provided controlled release of magnesium and zinc ions, promoting cell proliferation and vitality. In vitro studies demonstrated significant osteogenic and chondrogenic properties, as well as antibacterial efficacy. Proteomic analysis revealed the underlying mechanism of osteochondral integrated repair facilitated by the scaffold. Micro-CT evaluation and histological analysis confirmed successful osteochondral integration in the rabbit model. Discussion: The biomimetic honeycomb-like scaffold (Zn-AlgMA@Mg) demonstrated promising results for osteochondral repair, effectively addressing the challenges posed by bacterial tissue conditions. The scaffold's ability to release magnesium and zinc ions in a controlled manner contributed to its significant osteogenic, chondrogenic, and antibacterial properties. Proteomic analysis provided insights into the scaffold's mechanism of action, supporting its potential for integrated osteochondral regeneration. The successful in vivo results highlight the scaffold's efficacy, making it a promising biomaterial for future applications in osteochondral repair.

Fabrication and characterizations of simvastatin-containing mesoporous bioactive glass and molybdenum disulfide scaffold for bone tissue engineering

Due to the limitations of the current treatment approaches of allograft and autograft techniques, treating bone disorders is a significant challenge. To address these shortcomings, a novel biomaterial composite is required. This study presents the preparation and fabrication of a novel biomaterial composite scaffold that combines poly (D, L-lactide-co-glycolide) (PLGA), mesoporous bioactive glass (MBG), molybdenum disulfide (MoS2), and simvastatin (Sim) to address the limitations of current bone grafting techniques of autograft and allograft. The fabricated scaffold of PLGA-MBG-MoS2-Sim composites was developed using a low-cost hydraulic press and salt leaching method, and scanning electron microscopy (SEM) analysis confirmed the scaffolds have a pore size between 143 and 240 μm. The protein adsorption for fabricated scaffolds was increased at 24 h. The water adsorption and retention studies showed significant results on the PLGA-MBG-MoS2-Sim composite scaffold. The biodegradation studies of the PLGA-MBG-MoS2-Sim composite scaffold have shown 54% after 28 days. In vitro, bioactivity evaluation utilizing simulated body fluid studies confirmed the development of bone mineral hydroxyapatite on the scaffolds, which was characterized using x-ray diffraction, Fourier transform infrared, and SEM analysis. Furthermore, the PLGA-MBG-MoS2-Sim composite scaffold is biocompatible with C3H10T1/2 cells and expresses more alkaline phosphatase and mineralization activity. Additionally, in vivo research showed that PLGA-MBG-MoS2-Sim stimulates a higher rate of bone regeneration. These findings highlight the fabricated PLGA-MBG-MoS2-Sim composite scaffold presents a promising solution for the limitations of current bone grafting techniques.

Current Trend and New Opportunities for Multifunctional Bio-Scaffold Fabrication via High-Pressure Foaming

Biocompatible and biodegradable foams prepared using the high-pressure foaming technique have been widely investigated in recent decades as porous scaffolds for in vitro and in vivo tissue growth. In fact, the foaming process can operate at low temperatures to load bioactive molecules and cells within the pores of the scaffold, while the density and pore architecture, and, hence, properties of the scaffold, can be finely modulated by the proper selection of materials and processing conditions. Most importantly, the high-pressure foaming of polymers is an ideal choice to limit and/or avoid the use of cytotoxic and tissue-toxic compounds during scaffold preparation. The aim of this review is to provide the reader with the state of the art and current trend in the high-pressure foaming of biomedical polymers and composites towards the design and fabrication of multifunctional scaffolds for tissue engineering. This manuscript describes the application of the gas foaming process for bio-scaffold design and fabrication and highlights some of the most interesting results on: (1) the engineering of porous scaffolds featuring biomimetic porosity to guide cell behavior and to mimic the hierarchical architecture of complex tissues, such as bone; (2) the bioactivation of the scaffolds through the incorporation of inorganic fillers and drugs.

A Review on Manufacturing Processes of Biocomposites Based on Poly(α-Esters) and Bioactive Glass Fillers for Bone Regeneration

The incorporation of bioactive and biocompatible fillers improve the bone cell adhesion, proliferation and differentiation, thus facilitating new bone tissue formation upon implantation. During these last 20 years, those biocomposites have been explored for making complex geometry devices likes screws or 3D porous scaffolds for the repair of bone defects. This review provides an overview of the current development of manufacturing process with synthetic biodegradable poly(α-ester)s reinforced with bioactive fillers for bone tissue engineering applications. Firstly, the properties of poly(α-ester), bioactive fillers, as well as their composites will be defined. Then, the different works based on these biocomposites will be classified according to their manufacturing process. New processing techniques, particularly additive manufacturing processes, open up a new range of possibilities. These techniques have shown the possibility to customize bone implants for each patient and even create scaffolds with a complex structure similar to bone. At the end of this manuscript, a contextualization exercise will be performed to identify the main issues of process/resorbable biocomposites combination identified in the literature and especially for resorbable load-bearing applications.

Determining the Optimal Conditions for the Production by Supercritical CO2 of Biodegradable PLGA Foams for the Controlled Release of Rutin as a Medical Treatment

Poly(D,L,-lactide-co-glycolide) (PLGA) foam samples impregnated with rutin were successfully produced by supercritical foaming processes. A number of parameters such as pressure (80–200 bar), temperature (35–55 °C), depressurization rate (5–100 bar/min), ratio lactide:glycolide of the poly(D,L,-lactide-co-glycolide) (50:50 and 75:25) were studied to determine their effect on the expansion factor and on the glass transition temperature of the polymer foams and their consequences on the release profile of the rutin entrapped in them. The impregnated foams were characterized by scanning electron microscopy, differential scanning calorimetry, and mercury intrusion porosimetry. A greater impregnation of rutin into the polymer foam pores was observed as pressure was increased. The release of rutin in a phosphate buffer solution was investigated. The controlled release tests confirmed that the modification of certain variables would result in considerable differences in the drug release profiles. Thus, five-day drug release periods were achieved under high pressure and temperature while the depressurization rate remained low.