Tissue Regeneration Applications Research Articles

The Effects of Different Developmental Stages on Bone Regeneration of Periodontal Ligament Stem Cells and Periodontal Ligament Cell Sheets In Vitro and Vivo.

Periodontal ligament stem cells (PDLSCs) have broad applications in tissue engineering and regeneration. However, the function of PDLSCs changes in different microenvironments. This study aimed to explore the effects of different developmental stages on the biological characteristics of PDLSCs. Here, PDLSCs were successfully cultured from the periodontal tissues of various groups, including a group with immature roots, a young group with mature roots, and an aging group with mature roots. By comparing the results of the three experimental groups, we found that the donors with immature roots exhibited the best proliferative ability and osteogenic differentiation, while the aging group demonstrated the worst proliferation. The trend for adipogenic differentiation was the opposite to that for osteogenic differentiation. The cell sheet and in vivo experiments revealed that in the immature root group, the cells produced more extracellular matrix (ECM) and new bone and better absorbed the implant materials. These results indicate that PDLSCs perform various functions at different stages of development. In clinical applications of PDLSCs for periodontal regeneration, donors with incompletely developed roots have stronger biological characteristics.

Biocompatibility and expression of transcription factors of a type B gelatin-Extracellular Matrix of Porcin Urinary Blader scaffold.

to evaluate a membrane based on type B gelatin (G) and porcine urinary bladder extracellular matrix (PUB-EM), highlighting the potential effect of the combination evaluated by biocompatibility and regulation of the expression of transcription factors involved in tissue regeneration. G-PUB-EM membranes were prepared at 12.5, 25, and 50% w/v, and evaluated for biocompatibility with Fibroblast. Chemical characterization by FTIR-ATR showed complex spectra during crosslinking process with glutaraldehyde. Physical tests were performed in deionized water and PBS for 48 h. A significant increase in swelling was observed during the first 2 h. Biocompatibility testing (MTS) and evaluation of the expression profile of genes involved in the cell cycle (Cyclin-D1 VEGF, TNF and NF-κ-B) by PCR showed an increase in viability in a PUB-EM content-dependent way, except for 50% PUB-EM membrane which showed cytotoxic effects with a decrease in cell viability below 70%. The membranes showed an increase in the expression of some factors of cell cycle, as well as inflammatory processes that could promote tissue repair. 12.5 and 25% gelatin type B/porcine urinary bladder extracellular matrix (G/PUB-EM) based membranes have potential for tissue regeneration applications. The use of membranes based on type B gelatin and porcine urinary bladder for tissue engineering represents a novel strategy. Biocompatibility and signaling pathways play a primary role in tissue repair and wound recovery. Transcription factors that mediate signaling, cell division and vascularization are part of molecules that intervene in the regenerative potential of cells. These techniques will have a significant impact on tissue repair and regeneration and thus stop depending on tissue donors or other surgical sites from the same patient, as is the case with burn patients.

Directed Differentiation of Adipose-Derived Stem Cells Using Imprinted Cell-Like Topographies as a Growth Factor-Free Approach.

The influence of surface topography on stem cell behavior and differentiation has garnered significant attention in regenerative medicine and tissue engineering. The cell-imprinting method has been introduced as a promising approach to mimic the geometry and topography of cells. The cell-imprinted substrates are designed to replicate the topographies and dimensions of target cells, enabling tailored interactions that promote the differentiation of stem cells towards desired specialized cell types. In fact, by replicating the size and shape of cells, biomimetic substrates provide physical cues that profoundly impact stem cell differentiation. These cues play a pivotal role in directing cell morphology, cytoskeletal organization, and gene expression, ultimately influencing lineage commitment. The biomimetic substrates' ability to emulate the native cellular microenvironment supports the creation of platforms capable of steering stem cell fate with high precision. This review discusses the role of mechanical factors that impact stem cell fate. It also provides an overview of the design and fabrication principles of cell-imprinted substrates. Furthermore, the paper delves into the use of cell-imprinted polydimethylsiloxane (PDMS) substrates to direct adipose-derived stem cells (ADSCs) differentiation into a variety of specialized cells for tissue engineering and regenerative medicine applications. Additionally, the review discusses the limitations of cell-imprinted PDMS substrates and highlights the efforts made to overcome these limitations.

Emulsion-Templated Gelatin/Amino Acids/Chitosan Macroporous Hydrogels with Adjustable Internal Dimensions for Three-Dimensional Stem Cell Culture.

The demand for macroporous hydrogel scaffolds with interconnected porous and open-pore structures is crucial for advancing research and development in cell culture and tissue regeneration. Existing techniques for creating 3D porous materials and controlling their porosity are currently constrained. This study introduces a novel approach for producing highly interconnected aspartic acid-gelatin macroporous hydrogels (MHs) with precisely defined open pore structures using a one-step emulsification polymerization method with surface-modified silica nanoparticles as Pickering stabilizers. Macroporous hydrogels offer adjustable pore size and pore throat size within the ranges of 50 to 130 μm and 15 to 27 μm, respectively, achieved through variations in oil-in-water ratio and solid content. The pore wall thickness of the macroporous hydrogel can be as thin as 3.37 μm and as thick as 6.7 μm. In addition, the storage modulus of the macroporous hydrogels can be as high as 7250 Pa, and it maintains an intact rate of more than 92% after being soaked in PBS for 60 days, which is also good performance for use as a biomedical scaffold material. These hydrogels supported the proliferation of human dental pulp stem cells (hDPSCs) over a 30 day incubation period, stretching the cell morphology and demonstrating excellent biocompatibility and cell adhesion. The combination of these desirable attributes makes them highly promising for applications in stem cell culture and tissue regeneration, underscoring their potential significance in advancing these fields.

ECM-Mimicking Strontium-Doped Nanofibrous Microspheres for Periodontal Tissue Regeneration in Osteoporosis.

Regenerating periodontal defects in osteoporosis patients presents a significant clinical challenge. Unlike the relatively straightforward regeneration of homogeneous bone tissue, periodontal regeneration requires the intricate reconstruction of the cementum-periodontal ligament-alveolar bone interface. Strontium (Sr)-doped biomaterials have been extensively utilized in bone tissue engineering due to their remarkable pro-osteogenic attributes. However, their application in periodontal tissue regeneration has been scarcely explored. In this study, we synthesized an innovative injectable Sr-BGN/GNM scaffold by integrating Sr-doped bioactive glass nanospheres (Sr-BGNs) into the nanofiber architecture of gelatin nanofiber microspheres (GNMs). This design, mimicking the natural bone extracellular matrix (ECM), enhanced the scaffold's mechanical properties and effectively controlled the sustained release of Sr ions (Sr2+), thereby promoting the proliferation, osteogenic differentiation, and ECM secretion of PDLSCs and BMSCs, as well as enhancing vascularization in endothelial cells. In vivo experiments further indicated that the Sr-BGNs/GNMs significantly promoted osteogenesis and angiogenesis. Moreover, the scaffold's tunable degradation kinetics optimized the prolonged release and pro-regenerative effects of Sr2+ in vivo, matching the pace of periodontal regeneration and thereby facilitating the regeneration of functional periodontal tissues under osteoporotic conditions. Therefore, Sr-BGNs/GNMs emerge as a promising candidate for advancing periodontal regeneration strategies.

Value-Added Nanocellulose Valorized from Fruit Peel Waste for Potential Dermal Wound Healing and Tissue Regenerative Applications

Value-Added Nanocellulose Valorized from Fruit Peel Waste for Potential Dermal Wound Healing and Tissue Regenerative Applications

Organic-inorganic nHA-Gelatin/Alginate high strength macroporous cryogel promotes bone regeneration

Macroporous cryogel has the advantages of nutrient exchange and cell growth, and is an ideal material for tissue regeneration. In order to strengthen the machenical properties of cryogel for the widely use, a high strength gelatin/sodium alginate/nano hydroxyapatite (nHA) porous cryogel (GA-HA cryogel) was prepared by a simple freeze-thaw process. The mechanical strength of GA-HA cryogel increased significantly with the increase of nHA content. In vitro studies showed that GA-HA cryogel had good biocompatibility and no obvious cytotoxicity to MC3T3-E1 cells. The results of alkaline phosphatase activity assay and osteocalcin immunofluorescence staining showed that GA-HA1 porous hydrogel system could significantly increase the expression of MC3T3-E1 alkaline phosphatase and osteocalcin when the content of nHA was 1 ​%. In addition, porous GA-HA cryogel showed good performance in promoting bone regeneration in rat skull defect model. Therefore, the high-strength double network cryogel prepared in this study can provide new applications in bone repair and tissue regeneration.

Enhancement of the chondrogenic differentiation capacity of human dental pulp stem cells via chondroitin sulfate-coated polycaprolactone-MWCNT nanofibers

Most of the conditions involving cartilaginous tissues are irreversible and involve degenerative processes. The aim of the present study was to fabricate a biocompatible fibrous and film scaffolds using electrospinning and casting techniques to induce chondrogenic differentiation for possible application in cartilaginous tissue regeneration. Polycaprolactone (PCL) electrospun nanofibrous scaffolds and PCL film were fabricated and incorporated with multi-walled carbon nanotubes (MWCNTs). Thereafter, coating of chondroitin sulfate (CS) on the fibrous and film structures was applied to promote chondrogenic differentiation of human dental pulp stem cells (hDPSCs). First, the morphology, hydrophilicity and mechanical properties of the scaffolds were characterized by scanning electron microscopy (SEM), spectroscopic characterization, water contact angle measurements and tensile strength testing. Subsequently, the effects of the fabricated scaffolds on stimulating the proliferation of human dental pulp stem cells (hDPSCs) and inducing their chondrogenic differentiation were evaluated via electron microscopy, flow cytometry and RT‒PCR. The results of the study demonstrated that the different forms of the fabricated PCL-MWCNTs scaffolds analyzed demonstrated biocompatibility. The nanofilm structures demonstrated a higher rate of cellular proliferation, while the nanofibrous architecture of the scaffolds supported the cellular attachment and differentiation capacity of hDPSCs and was further enhanced with CS addition. In conclusion, the results of the present investigation highlighted the significance of this combination of parameters on the viability, proliferation and chondrogenic differentiation capacity of hDPSCs seeded on PCL-MWCNT scaffolds. This approach may be applied when designing PCL-based scaffolds for future cell-based therapeutic approaches developed for chondrogenic diseases.

Composite Hydrogel Sealants for Annulus Fibrosus Repair.

Intervertebral disc (IVD) herniation is a leading cause of disability and lower back pain, causing enormous socioeconomic burdens. The standard of care for disc herniation is nucleotomy, which alleviates pain but does not repair the annulus fibrosus (AF) defect nor recover the biomechanical function of the disc. Existing bioadhesives for AF repair are limited by insufficient adhesion and significant mechanical and geometrical mismatch with the AF tissue, resulting in the recurrence of protrusion or detachment of bioadhesives. Here, we report a composite hydrogel sealant constructed from a composite of a three-dimensional (3D)-printed thermoplastic polyurethane (TPU) mesh and tough hydrogel. We tailored the fiber angle and volume fraction of the TPU mesh design to match the angle-ply structure and mechanical properties of native AF. Also, we proposed and tested three types of geometrical design of the composite hydrogel sealant to match the defect shape and size. Our results show that the sealant could mimic native AF in terms of the elastic modulus, flexural modulus, and fracture toughness and form strong adhesion with the human AF tissue. The bovine IVD tests show the effectiveness of the composite hydrogel sealant for AF repair and biomechanics recovery and for preventing herniation with its heightened stiffness and superior adhesion. By harnessing the combined capabilities of 3D printing and bioadhesives, these composite hydrogel sealants demonstrate promising potential for diverse applications in tissue repair and regeneration.

Fabrication and Characterization of Collagen–Magnetic Particle Composite Microbeads for Targeted Cell Adhesion and Proliferation

The integration of the biocompatibility of collagen and the remote-control ability of magnetic elements serves as both a cell scaffold and an actuator. We studied the preparation, characterization, and potential applications of collagen–magnetic particle composite microbeads (CMPMBs). The interplay among collagen concentration, particle size, and surface roughness was found to influence cell adhesion and proliferation. Adsorption and desorption tests showed the reversible attachment of the particles to magnetic sheets, enabling precise spatial control and targeted cell delivery. The particles demonstrated their utility as cell carriers, supporting cell migration and proliferation. These findings showcase the potential of CMPMBs as a promising platform for advanced cell delivery and tissue regeneration applications. The ability to fine-tune particle properties and manipulate them using magnetic fields offers new possibilities for creating complex tissue constructs and controlling cellular behavior, which could contribute to the development of more effective regenerative therapies and tissue engineering approaches.

P-790 Engineering Vascularized Human Endometrial Organoids for In Vivo Tissue Regeneration and Repair Applications

Abstract Study question Is it possible to construct a vascularized endometrial organoid in vitro using endometrial epithelial organoids, endometrial stromal cells, and HUVECs? And its application value? Summary answer We have successfully engineered a vascularized endometrial organoid and demonstrated its remarkable ability to repair damaged endometrium. ScRNA-sequencing revealed intricate regulatory relationships among the cells. What is known already In vivo, endometrial epithelial organoids (EEOs) have been proven effective in repairing damaged endometrium. In vitro, when co-cultured with endometrial stromal cells (ESCs) in matrigel, EEOs self-assemble into endometrial assembloids that accurately replicate the native tissue’s characteristics. Endothelial cells play a critical regulatory role in various physiological processes across different tissues, such as lipid metabolism in hepatocytes, neurogenesis within the brain, and the menstrual cycle regulation in uterine endometrium. By leveraging organ-on-a-chip technology using HUVECs (commonly utilized endothelial cells), it is possible to construct functional and complex organoids with vascularization, including liver buds, brain organoids, and pancreatic islets. Study design, size, duration Different ratios of Fibrin and Matrigel were explored to optimize the hydrogel conditions. The composite medium was optimized with ExM and ECM. Cellular interactions were identified through cell-specific staining. Addition of reproductive hormones was performed to determine if the complexes exhibited hormone-responsive behavior. Transplantation of the organoid complexes into mice with endometrial injury was conducted to assess their repair capacity. Single-cell RNA sequencing was employed to identify cell clusters and analyze intercellular interactions. Participants/materials, setting, methods EEOs, ESCs, and HUVECs self-assemble into HEO complexes. EEOs and ESCs self-assemble into EO complexes as controls. Immunofluorescence and immunohistochemical analysis are conducted to detect cell-specific markers. PBS, Matrigel, EO and HEO complexes are transplanted into mice with endometrial injury. JC-1 staining and transmission electron microscopy are used to verify mitochondrial functionality. Electrical resistance measured by EVOM2, HUVEC tubule formation and sprouting assays are performed to investigate the formation of vascular networks within the complexes. Main results and the role of chance Under dynamic flow conditions of ExM and ECM at a ratio of 5:5, HEO complexes and EO complexes were self-assembled in a fibrin-matrigel hydrogel. The HEO complexes exhibited a capillary network-like structure, intricate cellular interactions, and a transcriptome profile similar to that of the in vivo endometrium. Moreover, HEO complexes responded to sex hormones, facilitating endometrial regeneration and improving the reproductive capacity of mice with endometrial injury. The subcutaneous transplantation of HEO complexes in mice revealed the perfusion of mouse blood within the human blood vessel network in the grafts, highlighting the participation of HUVECs in the vascular formation of the transplanted grafts. ScRNA sequencing analysis of HEO complexes demonstrated a notable rise in the proportion of proliferative subclusters of endometrial epithelial cells and stromal cells compared to EO complexes, especially under estrogen culture conditions. Additionally, HUVECs enhanced the mitochondrial functionality of endometrial cells and remodeled the extracellular matrix. Cell communication analysis revealed that endometrial epithelial and stromal cells enhance the formation of vascular networks in HUVECs within the HEO complexes through WNT7A and WNT5A signaling pathways. Limitations, reasons for caution Due to the time constraints of the study, we did not observe the birth rate of offspring mice following endometrial repair. ScRNA sequencing also uncovered that HUVECs promote ribosomal functionality in endometrial cells within HEO complexes, but further validation of this finding is necessary. Wider implications of the findings The implantation of HEO complexes derived from woman EEOs, ESCs, and HUVECs into the endometrium holds potential for “endometrial re-engineering” in the therapeutic management of Asherman’s syndrome or thin endometrium. Trial registration number not applicable

Alginate-Sr/Mg Containing Bioactive Glass Scaffolds: The Characterization of a New 3D Composite for Bone Tissue Engineering.

In bone regeneration, combining natural polymer-based scaffolds with Bioactive Glasses (BGs) is an attractive strategy to improve the mechanical properties of the structure, as well as its bioactivity and regenerative potential. Methods: For this purpose, a well-studied alginate/hydroxyapatite (Alg/HAp) porous scaffold was enhanced with an experimental bioglass (BGMS10), characterized by a high crystallization temperature and containing therapeutic ions such as strontium and magnesium. This resulted in an improved biological response compared to 45S5 Bioglass®, the "gold" standard among BGs. Porous composite scaffolds were fabricated by freeze-drying technique and characterized by scanning electron microscopy and microanalysis, infrared spectroscopy, and microcomputed tomography. The mechanical properties and cytocompatibility of the new scaffold composition were also evaluated. The addition of bioglass to the Alg/HAp network resulted in a slightly lower porosity. However, despite the change in pore size, the MG-63 cells were able to better adhere and proliferate when cultured for one week on a BG scaffold compared to the control Alg/HAp scaffolds. Thus, our findings indicate that the combination of bioactive glass BGMS10 does not affect the structural and physicochemical properties of the Alg/HAp scaffold and confers bioactive properties to the structures, making the Alg/HAp-BGMS10 scaffold a promising candidate for future application in bone tissue regeneration.

Biomimetic Bi3+ substituted borate bioactive glasses for bone tissue engineering via enhanced biological and antimicrobial activity

Biomimetic borate-based bioactive glasses (BAGs), substituted with metal oxides, serve as prominent candidates for the repair and regeneration of both hard and soft tissues. In the current study, bismuth mixed borate BAGs (60-X) B2O3–25CaO–15Na2O–XBi2O3 (X = 2, 4, 6, 8 & 10 mol.%) were synthesized using melt-quench method and systematically evaluated for their structural properties, followed by in-vitro biological performance and enhanced antimicrobial activity, using various characterization techniques and bioassays. The BAG structure was studied by Fourier transform infrared (FTIR), differential thermal analysis (DTA), and X-ray photoelectron spectroscopy (XPS) methods. The density and mechanical properties of the BAGs were found to increase with increase in bismuth content of the borate glass network. The XPS analysis confirmed the presence of Bi3+ ions embedded in the glass network. From DTA, it is noticed that the glass transition temperature (Tg) decreased and thermal stability (ΔT) values increased, with increased Bi2O3 content. Further, the bioactivity via hydroxy apatite (HAp) layer formation was confirmed by X-ray diffraction (XRD), FTIR, scanning electron microscopy- energy dispersive spectra (SEM-EDS) and Atomic force microscopy (AFM), both before and after soaking the glass samples in simulated body fluid (SBF) for 0, 7, 14, and 21 days. The results revealed that Bi3+ modified borate BAGs exhibited good HAp layer formation on their surfaces upon immersion in SBF solution. Moreover, the pH variation and degradation followed a trend, with increased in immersion time and decrease with Bi2O3 content. Lastly, in vitro cell culture tests on MG-63 osteoblast-like cells demonstrated that the as-developed BAGs were non-toxic and cytocompatible in nature; in addition, they also displayed demonstrable antibacterial activity against S. aureus and E. coli bacterial strains. Thus, the developed Bi2O3 mixed borate BAGs become suitable candidates for bone substitutes, especially for bone tissue regeneration and repair applications.

Preparation and characterization of poly (lactic acid)-chitosan blend fibrous electrospun membrane loaded with bioactive glass nanoparticles for guided bone/tissue regeneration

In this study, bioactive fibrous membranes composed of poly (lactic) acid (PLA), chitosan (CHS), and strontium-doped bioactive glass nanoparticles (BG) were produced via electrospinning technique using a triple solvent system and characterized via thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), static contact angle (CA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX).All fiber samples exhibited consistent one-step thermal degradation profiles, regardless of BG content, and the intended BG contents in the membranes ware confirmed. The addition of 3% w/w CHS to form PLA-CHS blend lowered the glass transition temperature (Tg) by 1.62 °C. FTIR analysis validated the presence of CHS in the PLA-CHS blend fibers through the appearance of a low-intensity broad peak around 1658–1566 cm⁻1, indicating primary amide functional groups. Incorporating 3% w/w CHS reduced water contact angle by 7% and decreased fiber diameter by 57%. Wettability improved with increasing BG content, as confirmed by SEM images showing well-dispersed BG nanoparticles within the fibers.After 35 days of immersion in simulated body fluid (SBF), a substantial layer of hydroxyapatite (HA) with a Ca/P ratio resembling that of natural human bones coated the BG particles and fibers. The membranes demonstrated excellent cell adhesion capabilities, especially in the PLA_3%CHS and PLA_3% CHS_5% BG configurations, with minimal cellular toxicity compared to a well-known cell-killing agent, highlighting their biocompatibility.Incorporating chitosan and strontium-doped bioactive glass nanoparticles into PLA blends positively influenced cell viability and proliferation, emphasizing the enhanced cellular response resulting from surface modifications. These properties make these fibrous membranes promising for guided bone and tissue regeneration applications.

New Generation of Osteoinductive and Antimicrobial Polycaprolactone-Based Scaffolds in Bone Tissue Engineering: A Review.

With respect to other fields, bone tissue engineering has significantly expanded in recent years, leading not only to relevant advances in biomedical applications but also to innovative perspectives. Polycaprolactone (PCL), produced in the beginning of the 1930s, is a biocompatible and biodegradable polymer. Due to its mechanical and physicochemical features, as well as being easily shapeable, PCL-based constructs can be produced with different shapes and degradation kinetics. Moreover, due to various development processes, PCL can be made as 3D scaffolds or fibres for bone tissue regeneration applications. This outstanding biopolymer is versatile because it can be modified by adding agents with antimicrobial properties, not only antibiotics/antifungals, but also metal ions or natural compounds. In addition, to ameliorate its osteoproliferative features, it can be blended with calcium phosphates. This review is an overview of the current state of our recent investigation into PCL modifications designed to impair microbial adhesive capability and, in parallel, to allow eukaryotic cell viability and integration, in comparison with previous reviews and excellent research papers. Our recent results demonstrated that the developed 3D constructs had a high interconnected porosity, and the addition of biphasic calcium phosphate improved human cell attachment and proliferation. The incorporation of alternative antimicrobials-for instance, silver and essential oils-at tuneable concentrations counteracted microbial growth and biofilm formation, without affecting eukaryotic cells' viability. Notably, this challenging research area needs the multidisciplinary work of material scientists, biologists, and orthopaedic surgeons to determine the most suitable modifications on biomaterials to design favourable 3D scaffolds based on PCL for the targeted healing of damaged bone tissue.

Production of ceramic alumina scaffolds via ceramic stereolithography with potential application in bone tissue regeneration

Scaffolds are devices that mimic the characteristics of the extracellular matrix; they are highly porous, with well-distributed and interconnected pores. Tissue engineering proposes scaffolds as an alternative treatment for different diseases and injuries affecting bone tissue. Triply periodic minimal surfaces (TPMS) are geometric structures whose characteristics fit well with the scaffold’s requirements. Ceramic stereolithography enables the production of these complex geometries with high precision using ceramic materials. Alumina (Al2O3) is a well-known ceramic material appreciated for its chemical and mechanical stability properties. The biomedical use of alumina as an alternative to replace metallic parts in bone components has been increasing. In this work, a suspension of alumina particles in a photopolymerizable resin is developed in order to be implemented in the printing of ceramic scaffolds with TPMS-type geometries by ceramic stereolithography for potential biomedical applications. The resin used was characterized in a different work by TGA and FTIR (Duque et al., 2023) and is acrylic in nature, also the alumina particles were characterized by DTP and XRD, these are micrometer sized and a showed an α-alumina phase with a high degree of crystallinity. The rheological behavior of the suspension was studied with ceramic load percentages of 35, 40, and 50 vol% in order to choose the most favorable conditions for piece printing. The three suspensions presented low viscosities, being the 50 vol% sample the one that presented the highest viscosity, with an average value of 0.77 Pa s. These viscosities were suitable for the ceramic stereolithography printing process. The 50 vol% suspension was characterized by TGA and DSC and did not show any difference compared to the resin without particles. Scaffolds with TPMS Gyroid and Schwartz P geometry were obtained by ceramic stereolithography and characterized morphologically and mechanically before and after sintering. The thermal treatment was successful. The polymer-ceramic scaffolds before sintering exhibited better compression resistance than the sintered ones. Fully ceramic scaffolds with gyroid geometry showed compressive strength values of 0.4 MPa, which is comparable to human trabecular bone. The best compression resistance was for the samples with the gyroid geometry. Since the 50 vol% sintered scaffolds with gyroid geometry showed better mechanical results, they were impregnated with propolis extracts from the Arauca region of Colombia in order to evaluate their antimicrobial activity against the standard strains Staphylococcus aureus (ATCC 29212) and Escherichia coli (ATCC 25922). The evaluated scaffolds exhibited better antibacterial activity against the S. aureus strain. After sintering, the 50Al scaffolds were submitted to a degradation test in phosphate-buffered saline (PBS) to assess the chemical stability of the alumina. The results indicated that the samples maintained their initial weight throughout the testing period, with measurements taken on days 1, 5, 8, and 12 showing no significant changes in weight loss percentage. This stability suggests that the alumina scaffolds possess robust chemical resistance under the tested conditions.

A gene edited pig model for studying LGR5+ stem cells: implications for future applications in tissue regeneration and biomedical research.

Recent advancements in genome editing techniques, notably CRISPR-Cas9 and TALENs, have marked a transformative era in biomedical research, significantly enhancing our understanding of disease mechanisms and helping develop novel therapies. These technologies have been instrumental in creating precise animal models for use in stem cell research and regenerative medicine. For instance, we have developed a transgenic pig model to enable the investigation of LGR5-expressing cells. The model was designed to induce the expression of H2B-GFP under the regulatory control of the LGR5 promoter via CRISPR/Cas9-mediated gene knock-in. Notably, advancements in stem cell research have identified distinct subpopulations of LGR5-expressing cells within adult human, mouse, and pig tissues. LGR5, a leucine-rich repeat-containing G protein-coupled receptor, enhances WNT signaling and these LGR5+ subpopulations demonstrate varied roles and anatomical distributions, underscoring the necessity for suitable translational models. This transgenic pig model facilitates the tracking of LGR5-expressing cells and has provided valuable insights into the roles of these cells across different tissues and species. For instance, in pulmonary tissue, Lgr5+ cells in mice are predominantly located in alveolar compartments, driving alveolar differentiation of epithelial progenitors via Wnt pathway activation. In contrast, in pigs and humans, these cells are situated in a unique sub-basal position adjacent to the airway epithelium. In fetal stages a pattern of LGR5 expression during lung bud tip formation is evident in humans and pigs but is lacking in mice. Species differences with respect to LGR5 expression have also been observed in the skin, intestines, and cochlea further reinforcing the need for careful selection of appropriate translational animal models. This paper discusses the potential utility of the LGR5+ pig model in exploring the role of LGR5+ cells in tissue development and regeneration with the goal of translating these findings into human and animal clinical applications.

Implantable Patch of Oxidized Nanofibrillated Cellulose and Lysozyme Amyloid Nanofibrils for the Regeneration of Infarcted Myocardium Tissue and Local Delivery of RNA-Loaded Nanoparticles.

Biopolymeric implantable patches are popular scaffolds for myocardial regeneration applications. Besides being biocompatible, they can be tailored to have required properties and functionalities for this application. Recently, fibrillar biobased nanostructures prove to be valuable in the development of functional biomaterials for tissue regeneration applications. Here, periodate-oxidized nanofibrillated cellulose (OxNFC) is blended with lysozyme amyloid nanofibrils (LNFs) to prepare a self-crosslinkable patch for myocardial implantation. The OxNFC:LNFs patch shows superior wet mechanical properties (60MPa for Young's modulus and 1.5MPa for tensile stress at tensile strength), antioxidant activity (70% scavenging activity under 24h), and bioresorbability ratio (80% under 91 days), when compared to the patches composed solely of NFC or OxNFC. These improvements are achieved while preserving the morphology, required thermal stability for sterilization, and biocompatibility toward rat cardiomyoblast cells. Additionally, both OxNFC and OxNFC:LNFs patches reveal the ability to act as efficient vehicles to deliver spermine modified acetalated dextran nanoparticles, loaded with small interfering RNA, with 80% of delivery after 5 days. This study highlights the value of simply blending OxNFC and LNFs, synergistically combining their key properties and functionalities, resulting in a biopolymeric patch that comprises valuable characteristics for myocardial regeneration applications.

Gallium-containing mesoporous nanoparticles influence in-vitro osteogenic and osteoclastic activity

Mesoporous silica nanoparticles were synthesized using a microemulsion-assisted sol-gel method, and calcium, gallium or a combination of both, were used as dopants. The influence of these metallic ions on the physicochemical properties of the nanoparticles was investigated by scanning and transmission electron microscopy, as well as N2 adsorption-desorption methods. The presence of calcium had a significant impact on the morphology and textural features of the nanoparticles. The addition of calcium increased the average diameter of the nanoparticles from 80 nm to 150 nm, while decreasing their specific surface area from 972 m2/g to 344 m2/g. The nanoparticles of all compositions were spheroidal, with a disordered mesoporous structure. An ion release study in cell culture medium demonstrated that gallium was released from the nanoparticles in a sustained manner. In direct contact with concentrations of up to 100 μg/mL of the nanoparticles, gallium-containing nanoparticles did not exhibit cytotoxicity towards pre-osteoblast MC3T3-E1 cells. Moreover, in vitro cell culture tests revealed that the addition of gallium to the nanoparticles enhanced osteogenic activity. Simultaneously, the nanoparticles disrupted the osteoclast differentiation of RAW 264.7 macrophage cells. These findings suggest that gallium-containing nanoparticles possess favorable physicochemical properties and biological characteristics, making them promising candidates for applications in bone tissue regeneration, particularly for unphysiological or pathological conditions such as osteoporosis.

Bacterial Cellulose: A Sustainable Source for Hydrogels and 3D-Printed Scaffolds for Tissue Engineering.

Bacterial cellulose is a biocompatible biomaterial with a unique macromolecular structure. Unlike plant-derived cellulose, bacterial cellulose is produced by certain bacteria, resulting in a sustainable material consisting of self-assembled nanostructured fibers with high crystallinity. Due to its purity, bacterial cellulose is appealing for biomedical applications and has raised increasing interest, particularly in the context of 3D printing for tissue engineering and regenerative medicine applications. Bacterial cellulose can serve as an excellent bioink in 3D printing, due to its biocompatibility, biodegradability, and ability to mimic the collagen fibrils from the extracellular matrix (ECM) of connective tissues. Its nanofibrillar structure provides a suitable scaffold for cell attachment, proliferation, and differentiation, crucial for tissue regeneration. Moreover, its mechanical strength and flexibility allow for the precise printing of complex tissue structures. Bacterial cellulose itself has no antimicrobial activity, but due to its ideal structure, it serves as matrix for other bioactive molecules, resulting in a hybrid product with antimicrobial properties, particularly advantageous in the management of chronic wounds healing process. Overall, this unique combination of properties makes bacterial cellulose a promising material for manufacturing hydrogels and 3D-printed scaffolds, advancing the field of tissue engineering and regenerative medicine.