Titanium-doped phosphate glasses containing zinc and strontium applied in bone regeneration.

Phosphate bioactive glass has been studied for its advanced biodegradability and active ion release capability. Our previous research found that phosphate glass containing (P2O5)-(Na2O)-(TiO2)-(CaO)-(SrO) or (ZnO) showed good biocompatibility with MG63 and hMSCs. This study further investigated the application of 5 mol% zinc oxide or 17.5 mol% strontium oxide in titanium-doped phosphate glass for bone tissue engineering. Ti-Ca-Na-Phosphate glasses, incorporating 5% zinc oxide or 17.5% strontium oxide, were made with melting quenching technology. The pre-osteoblast cell line MC3T3-E1 was cultured for indirect contact tests with graded diluted phosphate glass extractions and for direct contact tests by seeding cells on glass disks. The cell viability and cytotoxicity were analysed in vitro over 7 days. In vivo studies utilized the tibial defect model with or without glass implants. The micro-CT analysis was performed after surgery and then at 2, 6, and 12 weeks. Extractions from both zinc and strontium phosphate glasses showed no negative impact on MC3T3-E1 cell viability. Notably, non-diluted Zn-Ti-Ca-Na-phosphate glass extracts significantly increased cell viability by 116.8% (P < 0.01). Furthermore, MC3T3-E1 cells cultured with phosphate glass disks exhibited no increase in LDH release compared with the control group. Micro-CT images revealed that, over 12 weeks, both zinc-doped and strontium-doped phosphate glasses demonstrated good bone incorporation and longevity compared to the no-implant control. Titanium-doped phosphate glasses containing 5 mol% zinc oxide, or 17.5 mol% strontium oxide have promising application potential for bone regeneration research.

Multifunctional Molybdenum-Based Nanoclusters Engineered Gelatin Methacryloyl as In Situ Photo-Cross-Linkable Hybrid Hydrogel Dressings for Enhanced Wound Healing.

Skin injuries and wounds present significant clinical challenges, necessitating the development of advanced wound dressings for efficient wound healing and tissue regeneration. In this context, the advancement of hydrogels capable of counteracting the adverse effects arising from undesirable reactive oxygen species (ROS) is of significant importance. This study introduces a hybrid hydrogel with rapid photocuring and excellent conformability, tailored to ameliorate the hostile microenvironment of damaged skin tissues. The hybrid hydrogel, composed of photoresponsive Gelatin Methacryloyl (GelMA) and Molybdenum-based nanoclusters (MNC), exhibits physicochemical characteristics conductive to skin regeneration. In vitro studies demonstrated the cytocompatibility and ROS-responsive behavior of the MNC/GelMA hybrid hydrogels, confirming their ability to promote human dermal fibroblasts (HDF) functions. The incorporation of MNC into GelMA not only enhances HDF adhesion, proliferation, and migration but also shields against oxidative damage induced by hydrogen peroxide (H2O2). Notably, in vivo evaluation in murine full-thickness skin defects revealed that the application of hybrid hydrogel dressings led to reduced inflammation, accelerated wound closure, and enhanced collagen deposition in comparison to control groups. Significantly, this study introduced a convenient approach to develop in situ ROS-scavenging hydrogel dressings to accelerate the wound healing process without the need for exogenous cytokines or medications. We consider that the nanoengineering approach proposed herein offers potential possibilities for the development of therapeutic hydrogel dressings addressing various skin-related conditions.

Lithium-loaded GelMA-Phosphate glass fibre constructs: Implications for astrocyte response.

Combinations of different biomaterials with their own advantages as well as functionalization with other components have long been implemented in tissue engineering to improve the performance of the overall material. Biomaterials, particularly hydrogel platforms, have shown great potential for delivering compounds such as drugs, growth factors, and neurotrophic factors, as well as cells, in neural tissue engineering applications. In central the nervous system, astrocyte reactivity and glial scar formation are significant and complex challenges to tackle for neural and functional recovery. GelMA hydrogel-based tissue constructs have been developed in this study and combined with two different formulations of phosphate glass fibers (PGFs) (with Fe3+ or Ti2+ oxide) to impose physical and mechanical cues for modulating astrocyte cell behavior. This study was also aimed at investigating the effects of lithium-loaded GelMA-PGFs hydrogels in alleviating astrocyte reactivity and glial scar formation offering novel perspectives for neural tissue engineering applications. The rationale behind introducing lithium is driven by its long-proven therapeutic benefits in mental disorders, and neuroprotective and pronounced anti-inflammatory properties. The optimal concentrations of lithium and LPS were determined in vitro on primary rat astrocytes. Furthermore, qPCR was conducted for gene expression analysis of GFAP and IL-6 markers on primary astrocytes cultured 3D into GelMA and GelMA-PGFs hydrogels with and without lithium and in vitro stimulated with LPS for astrocyte reactivity. The results suggest that the combination of bioactive phosphate-based glass fibers and lithium loading into GelMA structures may impact GFAP expression and early IL-6 expression. Furthermore, GelMA-PGFs (Fe) constructs have shown improved performance in modulating glial scarring over GFAP regulation.

In Vivo Osteogenic and Angiogenic Properties of a 3D-Printed Isosorbide-Based Gyroid Scaffold Manufactured via Digital Light Processing.

INTRODUCTION: Osteogenic and angiogenic properties of synthetic bone grafts play a crucial role in the restoration of bone defects. Angiogenesis is recognised for its support in bone regeneration, particularly in larger defects. The objective of this study is to evaluate the new bone formation and neovascularisation of a 3D-printed isosorbide-based novel CSMA-2 polymer in biomimetic gyroid structures. METHODS: The gyroid scaffolds were fabricated by 3D printing CSMA-2 polymers with different hydroxyapatite (HA) filler concentrations using the digital light processing (DLP) method. A small animal subcutaneous model and a rat calvaria critical-size defect model were performed to analyse tissue compatibility, angiogenesis, and new bone formation. RESULTS: The in vivo results showed good biocompatibility of the 3D-printed gyroid scaffolds with no visible prolonged inflammatory reaction. Blood vessels were found to infiltrate the pores from day 7 of the implantation. New bone formation was confirmed with positive MT staining and BMP-2 expression, particularly on scaffolds with 10% HA. Bone volume was significantly higher in the CSMA-2 10HA group compared to the sham control group. DISCUSSION AND CONCLUSIONS: The results of the subcutaneous model demonstrated a favourable tissue response, including angiogenesis and fibrous tissue, indicative of the early wound healing process. The results from the critical-size defect model showcased new bone formation, as confirmed by micro-CT imaging and immunohistochemistry. The combination of CSMA-2 as the 3D printing material and the gyroid as the 3D structure was found to support essential events in bone healing, specifically angiogenesis and osteogenesis.

Strontium/Silicon/Calcium-Releasing Hierarchically Structured 3D-Printed Scaffolds Accelerate Osteochondral Defect Repair.

Articular cartilage defects are a global challenge, causing substantial disability. Repairing large defects is problematic, often exceeding cartilage's self-healing capacity and damaging bone structures. To tackle this problem, a scaffold-mediated therapeutic ion delivery system is developed. These scaffolds are constructed from poly(ε-caprolactone) and strontium (Sr)-doped bioactive nanoglasses (SrBGn), creating a unique hierarchical structure featuring macropores from 3D printing, micropores, and nanotopologies due to SrBGn integration. The SrBGn-embedded scaffolds (SrBGn-µCh) release Sr, silicon (Si), and calcium (Ca) ions, which improve chondrocyte activation, adhesion, proliferation, and maturation-related gene expression. This multiple ion delivery significantly affects metabolic activity and maturation of chondrocytes. Importantly, Sr ions may play a role in chondrocyte regulation through the Notch signaling pathway. Notably, the scaffold's structure and topological cues expedite the recruitment, adhesion, spreading, and proliferation of chondrocytes and bone marrow-derived mesenchymal stem cells. Si and Ca ions accelerate osteogenic differentiation and blood vessel formation, while Sr ions enhance the polarization of M2 macrophages. The findings show that SrBGn-µCh scaffolds accelerate osteochondral defect repair by delivering multiple ions and providing structural/topological cues, ultimately supporting host cell functions and defect healing. This scaffold holds great promise for osteochondral repair applications.

3D Porous Binary Composites of Collagen, Elastin, and Fibrin Proteins Orchestrate Adipose Tissue Regeneration.

The objective for this study is to advance the development of a specialized biomaterial that can effectively facilitate the regeneration of adipose tissue. In prior studies, the assessment of collagen (Col), elastin (Ela), and fibrin (Fib) unary scaffolds has been conducted. However, it is important to note that native adipose tissue is comprised of a diverse array of extracellular matrix (ECM) constituents. To mimic this behavior, binary compositions of collagen, elastin, and fibrin are fabricated in a 1:1 ratio, resulting in the formation of Col/Ela, Col/Fib, and Ela/Fib composites through a customized fabrication procedure. The physical properties of these scaffolds are comprehensively analyzed using a range of material characterization techniques. Additionally, the biological properties of the scaffolds are investigated by examining the survival, proliferation, and phenotype of adipose-derived stem cells. Subsequently, the aforementioned binary scaffolds are implanted into a rodent model for 28 days. the explants are analysed through X-ray microtomography, histology, and immunohistochemistry. The findings of the study demonstrate that the utilization of binary combinations of Col/Ela, Col/Fib, and Ela/Fib has a discernible impact on the physical and biological characteristics of the scaffolds. Nevertheless, Ela/Fib exhibits characteristics that make it a suitable candidate for adipogenesis due to its notable upregulation of caveolin-1 expression in both acellular and cellular cohorts. The combination of two natural polymers in this cell-material interaction has significantly enhanced the comprehension of adipogenesis.

The biological and therapeutic assessment of a P(3HB-co-4HB)-bioactive glass-graphene composite biomaterial for tissue regeneration.

An ideal wound dressing should create a healing environment that relieves pain, protects against infections, maintains moisture, removes debris, and speeds up wound closure and repair. However, conventional options like gauze often fall short in fulfilling these requirements, especially for chronic or nonhealing wounds. Hence there is a critical need for inventive formulations that offer efficient, cost-effective, and eco-friendly alternatives. This study focuses on assessing the innovative formulation based on a microbial-derived copolymer known as poly(3-hydroxybutyrate-co-4-hydroxybutyrate), P(3HB-co-4HB) bioactive glass and graphene particles, and exploring their biological response in vitro and in vivo-to find the best combination that promotes cell adhesion and enhances wound healing. The formulation optimized at concentration of bioactive glass (1 w/w%) and graphene (0.01 w/w%) showed accelerated degradation and enhanced blood vessel formation. Meanwhile biocompatibility was evaluated using murine osteoblasts, human dermal fibroblasts, and standard cell culture assays, demonstrating no adverse effects after 7 days of culture and well-regulated inflammatory kinetics. Whole thickness skin defect using mice indicated the feasibility of the biocomposites for a faster wound closure and reduced inflammation. Overall, this biocomposite appears promising as an ideal wound dressing material and positively influencing wound healing rates.

Multifunctional dendrimer@nanoceria engineered GelMA hydrogel accelerates bone regeneration through orchestrated cellular responses.

Bone defects in patients entail the microenvironment that needs to boost the functions of stem cells (e.g., proliferation, migration, and differentiation) while alleviating severe inflammation induced by high oxidative stress. Biomaterials can help to shift the microenvironment by regulating these multiple events. Here we report multifunctional composite hydrogels composed of photo-responsive Gelatin Methacryloyl (GelMA) and dendrimer (G3)-functionalized nanoceria (G3@nCe). Incorporation of G3@nCe into GelMA could enhance the mechanical properties of hydrogels and their enzymatic ability to clear reactive oxygen species (ROS). The G3@nCe/GelMA hydrogels supported the focal adhesion of mesenchymal stem cells (MSCs) and further increased their proliferation and migration ability (vs. pristine GelMA and nCe/GelMA). Moreover, the osteogenic differentiation of MSCs was significantly stimulated upon the G3@nCe/GelMA hydrogels. Importantly, the capacity of G3@nCe/GelMA hydrogels to scavenge extracellular ROS enabled MSCs to survive against H2O2-induced high oxidative stress. Transcriptome analysis by RNA sequencing identified the genes upregulated and the signalling pathways activated by G3@nCe/GelMA that are associated with cell growth, migration, osteogenesis, and ROS-metabolic process. When implanted subcutaneously, the hydrogels exhibited excellent tissue integration with a sign of material degradation while the inflammatory response was minimal. Furthermore, G3@nCe/GelMA hydrogels demonstrated effective bone regeneration capacity in a rat critical-sized bone defect model, possibly due to an orchestrated capacity of enhancing cell proliferation, motility and osteogenesis while alleviating oxidative stress.

Nanoceria-GO-intercalated multicellular spheroids revascularize and salvage critical ischemic limbs through anti-apoptotic and pro-angiogenic functions.

Critical limb ischemia (CLI) is a serious form of peripheral arterial disease that involves severe blockage of blood flow in lower extremities, often leading to foot necrosis and limb loss. Lack of blood flow and high pro-inflammation with overproduced reactive oxygen species (ROS) in CLI aggravate the degenerative events. Among other therapies, cell delivery is considered potential for restoring regenerative capacity, and preservation of cell survival under high oxidative stress has been challenging and prerequisite to harness cellular functions. Here, we introduce a multicellular delivery system that is intercalated with nanoceria-decorated graphene oxide (CeGO), which is considered to have high ROS scavenging ability while providing cell-matrix interaction signals. The CeGO nano-microsheets (8-nm-nanoceria/0.9-µm-GO) incorporated in HUVEC/MSC (7/3) could form cell-material hybrid spheroids mediated by cellular contraction. Under in vitro oxidative-stress-challenge with H2O2, the CeGO-intercalation enhanced the survival and anti-apoptotic capacity of cellular spheroids. Pro-angiogenic events of cellular spheroids, including cell sprouting and expression of angiogenic markers (HIF1α, VEGF, FGF2, eNOS) were significantly enhanced by the CeGO-intercalation. Proteomics analysis also confirmed substantial up-regulation of a series of angiogenesis-related secretome molecules. Such pro-angiogenic events with CeGO-intercalation were proven to be mediated by the APE/Ref-1 signaling pathway. When delivered to ischemic hindlimb in mice, the CeGO-cell spheroids could inhibit the accumulation of in vivo ROS rapidly, preserving high cell survival rate (cells were more proliferative and less apoptotic vs. those in cell-only spheroids), and up-regulated angiogenic molecular expressions. Monitoring over 28 days revealed significantly enhanced blood reperfusion and tissue recovery, and an ultimate limb salvage with the CeGO-cell delivery (∼60% salvaged vs. ∼29% in cell-only delivery vs. 0% in ischemia control). Together, the CeGO intercalated in HUVEC/MSC delivery is considered a potential nano-microplatform for CLI treatment, by scavenging excessive ROS and enhancing transplanted cell survival, while stimulating angiogenic events, which collectively help revascularization and tissue recovery, salvaging critical ischemic limbs.

Effect of lyophilized gelatin-norbornene cryogel size on calvarial bone regeneration.

Molding processes with molds containing topographical structures have been used for fabrication of hydrogel and cryogel particles. However, they can involve difficulties in separation of fabricated particles with complex shape from the molds or repeated fabrication of the particles although the overall processes do not require much skill and equipment. In this study, molds with etched superhydrophobic patterns have been developed by etching polytetrafluoroethylene (PTFE) blocks in user-defined designs with a femtosecond (FS) laser-based etching system. Lyophilized cryogel particles with various designs and sizes were fabricated by molding precursors with these PTFE molds. Additionally, the clean and easy separation of particles from the molds allowed repeated fabrication of the particles. For an application, relatively 'big' gelatin-norbornene (GelNB) cryogel particles prepared via molding with polydimethylsiloxane (PDMS) molds, swelling in phosphate buffered saline (PBS) and slicing height in half and 'small' GelNB cryogel particles fabricated with the PTFE molds were fabricated. Then, they were used to study scaffold size effect on calvarial bone regeneration. The molds generated with the FS laser-based etching system can be useful for various applications that require the mass production of cryogel particles in various geometries.

Diabetic bone regeneration with nanoceria-tailored scaffolds by recapitulating cellular microenvironment: Activating integrin/TGF-ß co-signaling of MSCs while relieving oxidative stress.

Regenerating defective bone in patients with diabetes mellitus remains a significant challenge due to high blood glucose level and oxidative stress. Here we aim to tackle this issue by means of a drug- and cell-free scaffolding approach. We found the nanoceria decorated on various types of scaffolds (fibrous or 3D-printed one; named nCe-scaffold) could render a therapeutic surface that can recapitulate the microenvironment: modulating oxidative stress while offering a nanotopological cue to regenerating cells. Mesenchymal stem cells (MSCs) recognized the nanoscale (tens of nm) topology of nCe-scaffolds, presenting highly upregulated curvature-sensing membrane protein, integrin set, and adhesion-related molecules. Osteogenic differentiation and mineralization were further significantly enhanced by the nCe-scaffolds. Of note, the stimulated osteogenic potential was identified to be through integrin-mediated TGF-ß co-signaling activation. Such MSC-regulatory effects were proven in vivo by the accelerated bone formation in rat calvarium defect model. The nCe-scaffolds further exhibited profound enzymatic and catalytic potential, leading to effectively scavenging reactive oxygen species in vivo. When implanted in diabetic calvarium defect, nCe-scaffolds significantly enhanced early bone regeneration. We consider the currently-exploited nCe-scaffolds can be a promising drug- and cell-free therapeutic means to treat defective tissues like bone in diabetic conditions.

Investigating the mechanophysical and biological characteristics of therapeutic dental cement incorporating copper doped bioglass nanoparticles.

OBJECTIVE: This study was investigated the mechanophysical properties of zinc phosphate cement (ZPC) with or without the copper doped bioglass nanoparticles (Cu-BGn) and their biological effect on dental pulp human cells and bacteria. MATERIALS AND METHODS: Cu-BGn were synthesized and characterized firstly and then, the experimental (Cu-ZPC) and control (ZPC) samples were fabricated with similar sizes and/or dimensions (diameter: 4 mm and height: 6 mm) based on the International Organization of Standards (ISO). Specifically, various concentrations of Cu-BGn were tested, and Cu-BGn concentration was optimized at 2.5 wt% based on the film thickness and overall setting time. Next, we evaluated the mechanophysical properties such as compressive strength, elastic modulus, hardness, and surface roughness. Furthermore, the biological behaviors including cell viability and odontoblastic differentiation by using dental pulp human cells as well as antibacterial properties were investigated on the Cu-ZPC. All data were analyzed statistically using SPSS® Statistics 20 (IBM®, USA). p < 0.05 (*) was considered significant, and 'NS' represents nonsignificant. RESULTS: Cu-BGn was obtained via a sol-gel method and added onto the ZPC for fabricating a Cu-ZPC composite and for comparison, the Cu-free-ZPC was used as a control. The film thickness (≤ 25 µm) and overall setting time (2.5-8 min) were investigated and the mechanophysical properties showed no significance ('NS') between Cu-ZPC and bare ZPC. However, cell viability and odontoblastic differentiation, alkaline phosphate (ALP) activity and alizarin red S (ARS) staining were highly stimulated in the extracts from the Cu-ZPC group compared to the ZPC group. Additionally, the antibacterial test showed that the Cu-ZPC extracts were more effective than the ZPC extracts (p < 0.05). SIGNIFICANCE: Cu-ZPC showed adequate mechanophysical properties (compressive strength, hardness, and surface roughness) and enhanced odontoblastic differentiation as well as antibacterial properties compared to the ZPC-only group. Based on the findings, the fabricated Cu-ZPC might have the potential for use in the field of dental medicine and clinical applications.

Therapeutic Application of an Ag-Nanoparticle-PNIPAAm-Modified Eggshell Membrane Construct for Dermal Regeneration and Reconstruction.

Current therapeutic treatments for the repair and/or replacement of damaged skin following disease or traumatic injury is severely limited. The chicken eggshell membrane (ESM) is a unique material: its innate physical and mechanical characteristics offer optimal barrier properties and, as a naturally derived extract, it demonstrates inherent biocompatibility/biodegradability. To further enhance its therapeutic and clinical potential, the ESM can be modified with the thermo-responsive polymer, poly(N-isopropylacrylAmide) (PNIPAAm) as well as the incorporation of (drug-loaded) silver nanoparticles (AgNP); essentially, by a simple change in temperature, the release and delivery of the NP can be targeted and controlled. In this study, ESM samples were isolated using a decellularization protocol, and the physical and mechanical characteristics were profiled using SEM, FT-IR, DSC and DMA. PNIPAAm was successfully grafted to the ESM via amidation reactions and confirmed using FT-IR, which demonstrated the distinctive peaks associated with Amide A (3275 cm−1), Amide B (2970 cm−1), Amide I (1630 cm−1), Amide II (1535 cm−1), CH2, CH3 groups, and Amide III (1250 cm−1) peaks. Confirmation of the incorporation of AgNP onto the stratified membrane was confirmed visually with SEM, qualitatively using FT-IR and also via changes in absorbance at 380 nm using UV-Vis spectrophotometry during a controlled release study for 72 h. The biocompatibility and cytotoxicity of the novel constructs were assessed using human dermal fibroblast (HDFa) and mouse dermal fibroblast (L929) cells and standard cell culture assays. Metabolic activity assessment (i.e., MTS assay), LDH-release profiles and Live/Dead staining demonstrated good attachment and spreading to the samples, and high cell viability following 3 days of culture. Interestingly, longer-term viability (>5 days), the ESM-PNIPAAm and ESM-PNIPAAm (AgNP) samples showed a greater and sustained cell viability profile. In summary, the modified and enhanced ESM constructs were successfully prepared and characterized in terms of their physical and mechanical profiles. AgNP were successfully loaded into the construct and demonstrated a desirable release profile dependent on temperature modulation. Fibroblasts cultured on the extracted ESM samples and ESM-PNIPAAm demonstrated high biocompatibility in terms of high cell attachment, spreading, viability and proliferation rates. As such, this work summarizes the development of an enhanced ESM-based construct which may be exploited as a clinical/therapeutic wound dressing as well as a possible application as a novel biomaterial scaffold for drug development.

Inclusion of calcium phosphate does not further improve in vitro and in vivo osteogenesis in a novel, highly biocompatible, mechanically stable and 3D printable polymer.

At a time of unpredictable challenges for health, one trend is certain: there is an exceedingly high demand for functional implants, particularly bone grafts. This has encouraged the emergence of bone tissue engineering substitutes as an alternative method to conventional bone grafts. However, the current approaches in the field face several limitations that have prevented the ultimate translation into clinical settings. As a result, many attempts have been made to fabricate synthetic bone implants that can offer suitable biological and mechanical properties.Light curable methacrylate-based polymers have ideal properties for bone repair. These materials are also suitable for 3D printing which can be applicable for restoration of both function and aesthetics. The main objective of this research was to investigate the role of calcium phosphate (CaP) incorporation in a mechanically stable, biologically functional and 3D printable polymer for the reconstruction of complex craniofacial defects. The experimental work initially involved the synthesis of (((((((((((3R,3aR,6S,6aR)- hexahydrofuro[3,2-b]furan-3,6-diyl)bis(oxy))bis(ethane-2,1- 48 diyl))bis(oxy))bis(carbonyl))bis(azanediyl))bis(3,3,5-trimethylcyclohexane-5,1- 49 diyl))bis(azanediyl))bis(carbonyl))bis(oxy))bis(ethane-2,1-diyl) bis(2-methylacrylate) referred to as CSMA and fabrication of composite discs via a Digital Light Printing (DLP) method. The flow behaviour of the polymer as a function of CaP addition, surface remineralisation potential, in vitro cell culture, using MC3T3 and Adipose-Derived Mesenchymal Stem Cells (ADSCs) and ex ovo angiogenic response was assessed. Finally, in vivo studies were carried out to investigate neo-bone formation at 4- and 8-weeks post-implantation. Quantitative micro-CT and histological evaluation did not show a higher rate of bone formation in CaP filled CSMA composites compared to CSMA itself. Therefore, such polymeric systems hold promising features by allowing more flexibility in designing a 3D printed scaffold targeted at the reconstruction of maxillofacial defects.

Hyperelastic, shape-memorable, and ultra-cell-adhesive degradable polycaprolactone-polyurethane copolymer for tissue regeneration.

Novel polycaprolactone-based polyurethane (PCL-PU) copolymers with hyperelasticity, shape-memory, and ultra-cell-adhesion properties are reported as clinically applicable tissue-regenerative biomaterials. New isosorbide derivatives (propoxylated or ethoxylated ones) were developed to improve mechanical properties by enhanced reactivity in copolymer synthesis compared to the original isosorbide. Optimized PCL-PU with propoxylated isosorbide exhibited notable mechanical performance (50 MPa tensile strength and 1150% elongation with hyperelasticity under cyclic load). The shape-memory effect was also revealed in different forms (film, thread, and 3D scaffold) with 40%-80% recovery in tension or compression mode after plastic deformation. The ultra-cell-adhesive property was proven in various cell types which were reasoned to involve the heat shock protein-mediated integrin (α5 and αV) activation, as analyzed by RNA sequencing and inhibition tests. After the tissue regenerative potential (muscle and bone) was confirmed by the myogenic and osteogenic responses in vitro, biodegradability, compatible in vivo tissue response, and healing capacity were investigated with in vivo shape-memorable behavior. The currently exploited PCL-PU, with its multifunctional (hyperelastic, shape-memorable, ultra-cell-adhesive, and degradable) nature and biocompatibility, is considered a potential tissue-regenerative biomaterial, especially for minimally invasive surgery that requires small incisions to approach large defects with excellent regeneration capacity.

Chemically-induced osteogenic cells for bone tissue engineering and disease modeling.

Cell reprogramming can satisfy the demands of obtaining specific cell types for applications such as tissue regeneration and disease modeling. Here we report the reprogramming of human fibroblasts to produce chemically-induced osteogenic cells (ciOG), and explore the potential uses of ciOG in bone repair and disease treatment. A chemical cocktail of RepSox, forskolin, and phenamil was used for osteogenic induction of fibroblasts by activation of RUNX2 expression. Following a maturation, the cells differentiated toward an osteoblast phenotype that produced mineralized nodules. Bulk and single-cell RNA sequencing identified a distinct ciOG population. ciOG formed mineralized tissue in an ectopic site of immunodeficiency mice, unlike the original fibroblasts. Osteogenic reprogramming was modulated under engineered culture substrates. When generated on a nanofiber substrate ciOG accelerated bone matrix formation in a calvarial defect, indicating that the engineered biomaterial promotes the osteogenic capacity of ciOG in vivo. Furthermore, the ciOG platform recapitulated the genetic bone diseases Proteus syndrome and osteogenesis imperfecta, allowing candidate drug testing. The reprogramming of human fibroblasts into osteogenic cells with a chemical cocktail thus provides a source of specialized cells for use in bone tissue engineering and disease modeling.

Mimicking Bone Extracellular Matrix: From BMP-2-Derived Sequences to Osteogenic-Multifunctional Coatings.

Cell-material interactions are regulated by mimicking bone extracellular matrix on the surface of biomaterials. In this regard, reproducing the extracellular conditions that promote integrin and growth factor (GF) signaling is a major goal to trigger bone regeneration. Thus, the use of synthetic osteogenic domains derived from bone morphogenetic protein 2 (BMP-2) is gaining increasing attention, as this strategy is devoid of the clinical risks associated with this molecule. In this work, the wrist and knuckle epitopes of BMP-2 are screened to identify peptides with potential osteogenic properties. The most active sequences (the DWIVA motif and its cyclic version) are combined with the cell adhesive RGD peptide (linear and cyclic variants), to produce tailor-made biomimetic peptides presenting the bioactive cues in a chemically and geometrically defined manner. Such multifunctional peptides are next used to functionalize titanium surfaces. Biological characterization with mesenchymal stem cells demonstrates the ability of the biointerfaces to synergistically enhance cell adhesion and osteogenic differentiation. Furthermore, in vivo studies in rat calvarial defects prove the capacity of the biomimetic coatings to improve new bone formation and reduce fibrous tissue thickness. These results highlight the potential of mimicking integrin-GF signaling with synthetic peptides, without the need for exogenous GFs.

Characterization of Physical and Biological Properties of a Caries-Arresting Liquid Containing Copper Doped Bioglass Nanoparticles.

Silver diamine fluoride (SDF) is an outstanding dental material for arresting and preventing caries, but some drawbacks, such as high flowability due to low viscosity and cytotoxicity to the pulp, have been reported. To overcome these problems, copper-doped bioactive glass nanoparticles (CuBGns) were combined with SDF. After synthesis, CuBGns were examined by physical analysis and added in SDF at different weight/volume% (SDF@CuBGn). After assessing physical properties (viscosity and flowability) of SDF@CuBGn, physicochemical properties (morphology before and after simulated body fluid (SBF) immersion and ion release) of SDF@CuBGn-applied hydroxyapatite (HA) discs were evaluated. Biological properties were further evaluated by cytotoxicity test to pulp stem cells and antibacterial effect on cariogenic organisms (Streptococcus mutans and Staphylococcus aureus). Combining CuBGns in SDF increased the viscosity up to 3 times while lowering the flowability. More CuBGns and functional elements in SDF (Ag and F) were deposited on the HA substrate, even after SBF immersion test for 14 days, and they showed higher Cu, Ca, and Si release without changing F and Ag release. Cell viability test suggested lower cytotoxicity in SDF@CuBGn-applied HA, while CuBGns in SDF boosted antibacterial effect against S. aureus, ~27% in diameter of agar diffusion test. In conclusion, the addition of CuBGn to SDF enhances viscosity, Ag and F deposition, and antibacterial effects while reducing cell toxicity, highlighting the role of bioactive CuBGns for regulating physical and biological effects of dental materials.

Protein-reactive nanofibrils decorated with cartilage-derived decellularized extracellular matrix for osteochondral defects.

Cartilage defect is difficult to heal due to its avascular properties. Implantation of mesenchymal stem cell is one of the most promising approach for regenerating cartilage defects. Here we prepared polymeric nanofibrils decorated with cartilage-derived decellularized extracellular matrix (dECM) as a chondroinductive scaffold material for cartilage repair. To fabricate nanofibrils, eletrospun PCL nanofibers were fragmented by subsequent mechanical and chemical process. The nanofibrils were surface-modified with poly(glycidyl methacrylate) (PGMA@NF) via surface-initiated atom transfer radical polymerization (SI-ATRP). The epoxy groups of PGMA@NF were subsequently reacted with dECM prepared from bovine articular cartilage. Therefore, the cartilage-dECM-decorated nanofibrils structurally and biochemically mimic cartilage-specific microenvironment. Once adipose-derived stem cells (ADSCs) were self-assembled with the cartilage-dECM-decorated nanofibrils by cell-directed association, they exhibited differentiation hallmarks of chondrogenesis without additional biologic additives. ADSCs in the nanofibril composites significantly increased expression of chondrogenic gene markers in comparison to those in pellet culture. Furthermore, ADSC-laden nanofibril composites filled the osteochondral defects compactly due to their clay-like texture. Thus, the ADSC-laden nanofibril composites supported the long-term regeneration of 12 weeks without matrix loss during joint movement. The defects treated with the ADSC-laden PGMA@NF significantly facilitated reconstruction of their cartilage and subchondral bone ECM matrices compared to those with ADSC-laden nanofibrils, non-specifically adsorbing cartilage-dECM without surface decoration of PGMA.

Mussel Inspired Chemistry and Bacteria Derived Polymers for Oral Mucosal Adhesion and Drug Delivery.

Ulceration of the oral mucosa is common, can arise at any age and as a consequence of the pain lessens enjoyment and quality of life. Current treatment options often involve the use of topical corticosteroids with poor drug delivery systems and inadequate contact time. In order to achieve local controlled delivery to the lesion with optimal adhesion, we utilized a simple polydopamine chemistry technique inspired by mussels to replicate their adhesive functionality. This was coupled with production of a group of naturally produced polymers, known as polyhydroxyalkanoates (PHA) as the delivery system. Initial work focused on the synthesis of PHA using Pseudomonas mendocina CH50; once synthesized and extracted from the bacteria, the PHAs were solvent processed into films. Polydopamine coating was subsequently achieved by immersing the solvent cast film in a polymerized dopamine solution. Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy confirmed functionalization of the PHA films via the presence of amine groups. Further characterization of the samples was carried out via surface energy measurements and Scanning Electron Microscopy (SEM) micrographs for surface topography. An adhesion test via reverse compression testing directly assessed adhesive properties and revealed an increase in polydopamine coated samples. To further identify the effect of surface coating, LIVE/DEAD imaging and Alamar Blue metabolic activity evaluated attachment and proliferation of fibroblasts on the biofilm surfaces, with higher cell growth in favor of the coated samples. Finally, in vivo biocompatibility was investigated in a rat model where the polydopamine coated PHA showed less inflammatory response over time compared to uncoated samples with sign of neovascularization. In conclusion, this simple mussel inspired polydopamine chemistry introduces a step change in bio-surface functionalization and holds great promise for the treatment of oral conditions.