3D Biomimetic Scaffolds Research Articles

Enhanced osteogenic differentiation in 3D hydrogel scaffold via macrophage mitochondrial transfer

To assess the efficacy of a novel 3D biomimetic hydrogel scaffold with immunomodulatory properties in promoting fracture healing. Immunomodulatory scaffolds were used in cell experiments, osteotomy mice treatment, and single-cell transcriptomic sequencing. In vitro, fluorescence tracing examined macrophage mitochondrial transfer and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Scaffold efficacy was assessed through alkaline phosphatase (ALP), Alizarin Red S (ARS) staining, and in vivo experiments. The scaffold demonstrated excellent biocompatibility and antioxidant-immune regulation. Single-cell sequencing revealed a shift in macrophage distribution towards the M2 phenotype. In vitro experiments showed that macrophage mitochondria promoted BMSCs’ osteogenic differentiation. In vivo experiments confirmed accelerated fracture healing. The GAD/Ag-pIO scaffold enhances osteogenic differentiation and fracture healing through immunomodulation and promotion of macrophage mitochondrial transfer.

The use of hyaluronic acid in a 3D biomimetic scaffold supports spheroid formation and the culture of cancer stem cells

Three-dimensional (3D) bioprinting culture models capable of reproducing the pathological architecture of diseases are increasingly advancing. In this study, 3D scaffolds were created using extrusion-based bioprinting method with alginate, gelatin, and hyaluronic acid to investigate the effects of hyaluronic acid on the physical properties of the bioscaffold as well as on the formation of liver cancer spheroids. Conformational analysis, rheological characterization, and swelling-degradation tests were performed to characterize the scaffolds. After generating spheroids from hepatocellular carcinoma cells on the 3D scaffolds, cell viability and proliferation assays were performed. Flow cytometry and immunofluorescence microscopy were used into examine the expression of albumin, CD44, and E-cadherin to demonstrate functional capability and maturation levels of the spheroid-forming cells. The results show that hyaluronic acid in the scaffolds correlates with spheroid formation and provides high survival rates. It is also associated with an increase in CD44 expression and a decrease in E-cadherin, while there is no significant change in the albumin expression in the cells. Overall, the findings demonstrate that hyaluronic acid in a 3D hydrogel scaffold supports spheroid formation and may induce stemness. We present a promising 3D scaffold model for enhancing liver cancer spheroid formation and mimicking solid tumors. This model also has the potential for further studies to examine stem cell properties in 3D models.

Induction and real-time ultrasonic monitoring of 3D cartilage-like tissue by a low shear stresses-based bioreactor

Osteoarthritis is a significant socioeconomic illness that mainly affects the articular cartilage, a tissue with a low capacity for self-healing, making it an ideal target for regenerative medicine and tissue engineering. Current interventions to treat cartilage injuries may not be completely effective. In this study, we have developed a novel bioreactor that creates viscous shear stress by flow perfusion. This bioreactor could induce ex vivo maturation of biomimetic 3D cartilage scaffolds, providing a potential solution to this problem. Infrapatellar fat pad mesenchymal stem cells (IPFP-MSCs) were used as a cellular source of the functionalized 3D scaffolds made of 1,4-butanediol thermoplastic polyurethane (bTPUe) modified with pyrene butyric acid (PBA). Our results indicate that our bioreactor induced chondrogenic differentiation, as confirmed by DNA quantification, extracellular matrix determination, and metabolic assay, without any conditioned medium. To control the biomechanical stimulation on IPFP-MSCs, a low-intensity ultrasonic transmission system has been developed and embedded in the bioreactor. Combined with a finite element model (FEM), tissue growth and differentiation can be deconvoluted in real-time from the recorded ultrasonic propagation and interaction across the graft. The FEM reconstructs this complex interaction. This is the first time a low-shear stress-based bioreactor has been reported to not only induce chondrogenic evolution but also monitor it in real time.

A Marine Collagen-Based 3D Scaffold for In Vitro Modeling of Human Prostate Cancer Niche and Anti-Cancer Therapeutic Discovery.

Recently, the need to develop a robust three-dimensional (3D) cell culture system that serves as a valuable in vitro tumor model has been emphasized. This system should closely mimic the tumor growth behaviors observed in vivo and replicate the key elements and characteristics of human tumors for the effective discovery and development of anti-tumor therapeutics. Therefore, in this study, we developed an effective 3D in vitro model of human prostate cancer (PC) using a marine collagen-based biomimetic 3D scaffold. The model displayed distinctive molecular profiles and cellular properties compared with those of the 2D PC cell culture. This was evidenced by (1) increased cell proliferation, migration, invasion, colony formation, and chemoresistance; (2) upregulated expression of crucial multidrug-resistance- and cancer-stemness-related genes; (3) heightened expression of key molecules associated with malignant progressions, such as epithelial-mesenchymal transition transcription factors, Notch, matrix metalloproteinases, and pluripotency biomarkers; (4) robust enrichment of prostate cancer stem cells (CSCs); and (5) enhanced expression of integrins. These results suggest that our 3D in vitro PC model has the potential to serve as a research platform for studying PC and prostate CSC biology, as well as for screening novel therapies targeting PC and prostate CSCs.

Construction of organ of Corti organoid to study the effects of berberine sulfate on damaged auditory cells.

Sensorineural hearing loss (SNHL) is mainly caused by injury or loss of hair cells (HCs) and associated spiral ganglion neurons (SGNs) in the inner ear. At present, there is still no effective treatment for SNHL in clinic. Recently, advances in organoid bring a promising prospect for research and treatment of SNHL. Meanwhile, three-dimensional (3D) printing provides a tremendous opportunity to construct versatile organoids for tissue engineering and regenerative medicine. In this study, gelatin (Gel), sodium alginate (SA), and polyvinyl alcohol (PVA) were used to fabricate biomimetic scaffold through 3D printing. The organ of Corti derived from neonatal mice inner ear was seeded on the PVA/Gel/SA scaffold to construct organ of Corti organoid. Then, the organ of Corti organoid was used to study the potential protective effects of berberine sulfate on neomycin-juried auditory HCs and SGNs. The results showed that the PVA/Gel/SA biomimetic 3D scaffolds had good cytocompatibilities and mechanical properties. The constructed organoid could maintain organ of Corti activity well in vitro. In addition, the injury intervention results showed that berberine sulfate could significantly inhibit neomycin-induced HC and SGN damage. This study suggests that the fabricated organoid is highly biomimetic to the organ of Corti, which may provide an effective model for drug development, cell and gene therapy for SNHL.

Machine learning to mechanically assess 2D and 3D biomimetic electrospun scaffolds for tissue engineering applications: Between the predictability and the interpretability

Currently, the use of autografts is the gold standard for the replacement of many damaged biological tissues. However, this practice presents disadvantages that can be mitigated through tissue-engineered implants. The aim of this study is to explore how machine learning can mechanically evaluate 2D and 3D polyvinyl alcohol (PVA) electrospun scaffolds (one twisted filament, 3 twisted filament and 3 twisted/braided filament scaffolds) for their use in different tissue engineering applications. Crosslinked and non-crosslinked scaffolds were fabricated and mechanically characterised, in dry/wet conditions and under longitudinal/transverse loading, using tensile testing. 28 machine learning models (ML) were used to predict the mechanical properties of the scaffolds. 4 exogenous variables (structure, environmental condition, crosslinking and direction of the load) were used to predict 2 endogenous variables (Young’s modulus and ultimate tensile strength). ML models were able to identify 6 structures and testing conditions with comparable Young’s modulus and ultimate tensile strength to ligamentous tissue, skin tissue, oral and nasal tissue, and renal tissue. This novel study proved that Classification and Regression Trees (CART) models were an innovative and easy to interpret tool to identify biomimetic electrospun structures; however, Cubist and Support Vector Machine (SVM) models were the most accurate, with R2 of 0.93 and 0.8, to predict the ultimate tensile strength and Young’s modulus, respectively. This approach can be implemented to optimise the manufacturing process in different applications.

Assessing the functional potential of conditioned media derived from amniotic epithelial stem cells engineered on 3D biomimetic scaffolds: An in vitro model for tendon regeneration

Tendon diseases pose a significant challenge in regenerative medicine due to the limited healing capacity of this tissue. Successful tendon regeneration requires a combination of angiogenesis, immune response, and tenogenesis processes. An effective tendon engineering (TE) strategy must finely tune this systems’ interplay toward homeostasis.This study explores in vitro the paracrine influence of amniotic epithelial stem cells (AECs) engineered on a validated 3D electrospun PLGA scaffolds on HUVECs (angiogenesis), PBMCs/Jurkat (immune response), and AECs (tenogenic stem cell activation).The results revealed the role of scaffold's topology and topography in significantly modulating the paracrine profile of the cells. In detail, AECs basal release of bioactive molecules was boosted in the cells engineered on 3D scaffolds, in particular VEGF-D, b-FGF, RANTES, and PDGF-BB (p < 0.0001 vs. CMCTR). Moreover, biological tests demonstrated 3D scaffolds' proactive role in potentiating AECs' paracrine inhibition on PBMCs proliferation (CM3Dvs. CTR, p < 0.001) and LPS-mediated Jurkat activation with respect to controls (CM3D and CM2Dvs. CTR, p < 0.01 and p < 0.05, respectively), without exerting any in vitro pro-angiogenic role in promoting HUVECs proliferation and tubule formation. Teno-inductive paracrine ability of AECs engineered on 3D scaffolds was assessed on co-cultured ones, which formed tendon-like structures. These latter demonstrated an upregulation of tendon-related genes (SCX, THBS4, COL1, and TNMD) and the expression TNMD and COL1 proteins.Overall, this research underscores the pivotal role of the 3D topology and topography of PLGA tendon mimetic scaffolds in orchestrating effective tendon regeneration through modulating cell behavior and crosstalk between engineered stem cells and different subpopulations in the damaged tendon.

Bioactive and biomimetic 3D scaffolds for bone tissue engineering using graphitic carbon nitride as a sustainable visible light photoinitiator

Graphitic carbon nitride (g-C3N4) is explored as a novel sustainable visible light photoinitiator for the preparation of biomimetic 3D hydrogel scaffolds comprising gelatin methacrylamide (GelMA) and dopamine methacrylamide for use in tissue engineering. The initiator efficiency was assessed by comparing the swelling behavior and the stability of photopolymerized hydrogels prepared with GelMA of different degrees of functionalization and different comonomer compositions. Bioactive composite hydrogels with a 50 wt% nanohydroxyapatite (nHAp) content, to closely mimic the actual bone composition, were successfully obtained by the introduction of nHAp in the prepolymer solutions followed by photopolymerization. The composite hydrogels demonstrated enhanced mechanical properties and excellent stability in PBS verifying the preparation of robust 3D scaffolds for use in cancellous or pre-calcified bone tissue engineering applications. The in vitro cell response of the composite scaffolds exhibited high cell viability and enhanced differentiation of pre-osteoblasts to mature osteoblasts, demonstrating their osteogenic potential. This work establishes, for the first time, the excellent properties of g-C3N4 as a sustainable, visible light initiator, fully satisfying the principles of green chemistry, for the preparation of robust and biologically relevant hydrogels, and proposes a new approach to overcome the main challenges of conventional photoinitiators in cell scaffold fabrication, such as photobleaching, high cost and non-scalable synthesis employing toxic organic precursors and solvents.

3D biomimetic scaffold’s dimensional accuracy: a crucial geometrical response for bone tissue engineering

Abstract Additive manufacturing has emerged as a trending methodology for producing different simple to complex geometries in minimum lead time, which in turn gives better quality attributes when compared to conventional manufacturing procedures. Fabrication of polylactic acid-based porous scaffold prototypes by 3-dimensional printing has been extensively performed successfully by many researchers. The dimensional accuracy of the 3-dimensional printed part is a very crucial aspect of bone tissue engineering. Dimensional precision of 3-dimensional biomimetic scaffolds has been a response characteristic somehow less focused on by researchers, though it is essential as it acts as a stereotype for defect recuperation while consequently developing extracellular matrix and bone regeneration. The present paper fosters re-tuning the process parameters of a fused deposition modeling based 3-dimensional printer while considering the dimensional precision as a response parameter by the Taguchi optimization technique using a full factorial design L27 orthogonal array set of design of experiments. The crystallinity of the polylactic acid filament material was assessed using differential scanning calorimetry and X-ray diffraction. The thermal breakdown of filament material was investigated utilizing a thermogravimetric analyzer. According to Taguchi’s signal-to-noise ratios, the optimum values were 0.14 mm of layer thickness, 20 mm s−1 of printing speed, and 80 % of infill percentage. In order to justify the results, response surface methodology was employed. R-square values for Taguchi and the response surface models were 88.61 % and 68.71 %, respectively.

Effects of transplantation of preconditioned mesenchymal stem cells seeded on a biomimetic 3D scaffold

Effects of transplantation of preconditioned mesenchymal stem cells seeded on a biomimetic 3D scaffold

Gelatin-based 3D biomimetic scaffolds platform potentiates culture of cancer stem cells in esophageal squamous cell carcinoma

Cancer stem cells (CSCs) are crucial for tumorigenesis, metastasis, and therapy resistance in esophageal squamous cell carcinoma (ESCC). To further elucidate the mechanism underlying characteristics of CSCs and develop CSCs-targeted therapy, an efficient culture system that could expand and maintain CSCs is needed. CSCs reside in a complex tumor microenvironment, and three-dimensional (3D) culture systems of biomimetic scaffolds are expected to better support the growth of CSCs by recapitulating the biophysical properties of the extracellular matrix (ECM). Here, we established gelatin-based 3D biomimetic scaffolds mimicking the stiffness and collagen content of ESCC, which could enrich ESCC CSCs efficiently. Biological changes of ESCC cells laden in scaffolds with three different viscoelasticity emulating physiological stiffness of esophageal tissues were thoroughly investigated in varied aspects such as cell morphology, viability, cell phenotype markers, and transcriptomic profiling. The results demonstrated the priming effects of viscoelasticity on the stemness of ESCC. The highly viscous scaffolds (G’: 6–403 Pa; G’’: 2–75 Pa) better supported the enrichment of ESCC CSCs, and the TGF-beta signaling pathway might be involved in regulating the stemness of ESCC cells. Compared to two-dimensional (2D) cultures, highly viscous scaffolds significantly promoted the clonal expansion of ESCC cells in vitro and tumor formation ability in vivo. Our findings highlight the crucial role of biomaterials’ viscoelasticity for the 3D culture of ESCC CSCs in vitro, and this newly-established culture system represents a valuable platform to support their growth, which could facilitate the CSCs-targeted therapy in the future.

Naturally Derived Maleic Chitosan/Thiolated Sodium Hyaluronate Hydrogels as Potential 3D Printing Tissue Engineering Materials

Abstract3D printing is an attractive method to accurately construct artificial organs or alternative materials with complicated structures and functional performance. Naturally derived hydrogels have emerged as promising materials for the preparation of biomimetic 3D organization or scaffolds by 3D printing due to their good biocompatibility, high water content, and fascinating 3D network. However, the poor printing properties and weak structural stability of naturally derived hydrogels limit their applications. In this study, photopolymerizable hydrogels are designed based on maleic chitosan (MCS) and thiolated sodium hyaluronate (SHHA). The Michael addition between MCS and SHHA improves the viscosity of the mixed solution. Moreover, it benefits the 3D printing process, followed by photopolymerization (acrylate‐thiol step‐chain polymerization and acrylate–acrylate chain polymerization) to form a stable covalent network rapidly. The rheological property, swelling behaviors, microstructure, and in vitro degradation are tuned by adjusting the molar ratio of the thiol group and acrylate group. In addition, MCS/SHHA hydrogel scaffolds with good accuracy and enhanced structural stability are prepared using extrusion‐based 3D printing and photopolymerization technology. The hydrogels display excellent cytocompatibility and can support adherence of L929 cells, which can be used as prospective materials for tissue engineering applications.

A 3D biomimetic optoelectronic scaffold repairs cranial defects.

Bone fractures and defects pose serious health-related issues on patients. For clinical therapeutics, synthetic scaffolds have been actively explored to promote critical-sized bone regeneration, and electrical stimulations are recognized as an effective auxiliary to facilitate the process. Here, we develop a three-dimensional (3D) biomimetic scaffold integrated with thin-film silicon (Si)-based microstructures. This Si-based hybrid scaffold not only provides a 3D hierarchical structure for guiding cell growth but also regulates cell behaviors via photo-induced electrical signals. Remotely controlled by infrared illumination, these Si structures electrically modulate membrane potentials and intracellular calcium dynamics of stem cells and potentiate cell proliferation and differentiation. In a rodent model, the Si-integrated scaffold demonstrates improved osteogenesis under optical stimulations. Such a wirelessly powered optoelectronic scaffold eliminates tethered electrical implants and fully degrades in a biological environment. The Si-based 3D scaffold combines topographical and optoelectronic stimuli for effective biological modulations, offering broad potential for biomedicine.

Polymeric microcarriers for minimally-invasive cell delivery.

Tissue engineering (TE) aims at restoring tissue defects by applying the three-dimensional (3D) biomimetic pre-formed scaffolds to restore, maintain, and enhance tissue growth. Broadly speaking, this approach has created a potential impact in anticipating organ-building, which could reduce the need for organ replacement therapy. However, the implantation of such cell-laden biomimetic constructs based on substantial open surgeries often results in severe inflammatory reactions at the incision site, leading to the generation of a harsh adverse environment where cell survival is low. To overcome such limitations, micro-sized injectable modularized units based on various biofabrication approaches as ideal delivery vehicles for cells and various growth factors have garnered compelling interest owing to their minimally-invasive nature, ease of packing cells, and improved cell retention efficacy. Several advancements have been made in fabricating various 3D biomimetic microscale carriers for cell delivery applications. In this review, we explicitly discuss the progress of the microscale cell carriers that potentially pushed the borders of TE, highlighting their design, ability to deliver cells and substantial tissue growth in situ and in vivo from different viewpoints of materials chemistry and biology. Finally, we summarize the perspectives highlighting current challenges and expanding opportunities of these innovative carriers.

Bioprinted anisotropic scaffolds with fast stress relaxation bioink for engineering 3D skeletal muscle and repairing volumetric muscle loss.

Viscoelastic hydrogels can enhance 3D cell migration and proliferation due to the faster stress relaxation promoting the arrangement of the cellular microenvironment. However, most synthetic photocurable hydrogels used as bioink materials for 3D bioprinting are typically elastic. Developing a photocurable hydrogel bioink with fast stress relaxation would be beneficial for 3D bioprinting engineered 3D skeletal muscles in vitro and repairing volumetric muscle loss (VML) in vivo; however, this remains an ongoing challenge. This study aims to develop an interpenetrating network (IPN) hydrogel with tunable stress relaxation using a combination of gelatin methacryloyl (GelMA) and fibrinogen. These IPN hydrogels with faster stress relaxation showed higher 3D cellular proliferation and better differentiation. A 3D anisotropic biomimetic scaffold was further developed via a printing gel-in-gel strategy, where the extrusion printing of cell-laden viscoelastic FG hydrogel within Carbopol supported gel. The 3D engineered skeletal muscle tissue was further developed via 3D aligned myotube formation and contraction. Furthermore, the cell-free 3D printed scaffold was implanted into a rat VML model, and both the short and long-term repair results demonstrated its ability to enhance functional skeletal muscle tissue regeneration. These data suggest that such viscoelastic hydrogel provided a suitable 3D microenvironment for enhancing 3D myogenic differentiation, and the 3D bioprinted anisotropic structure provided a 3D macroenvironment for myotube organization, which indicated the potential in skeletal muscle engineering and VML regeneration. STATEMENT OF SIGNIFICANCE: The development of a viscoelastic 3D aligned biomimetic skeletal muscle scaffold has been focused on skeletal muscle regeneration. However, a credible technique combining viscoelastic hydrogel and printing gel-in-gel strategy for fabricating skeletal muscle tissue was rarely reported. Therefore, in this study, we present an interpenetrating network (IPN) hydrogel with fast stress relaxation for 3D bioprinting engineered skeletal muscle via a printing gel-in-gel strategy. Such IPN hydrogels with tunable fast stress relaxation resulted in high 3D cellular proliferation and adequate differentiation in vitro. Besides, the 3D hydrogel-based scaffolds also enhance functional skeletal muscle regeneration in situ. We believe that this study provides several notable advances in tissue engineering that can be potentially used for skeletal muscle injury treatment in clinical.

Microstructure-based engineering of soft biological materials

Aortic disease (AoD) is a leading cause of mortality in developed countries. Two of the most common forms of AoD are aneurysm (widening) and dissection (tear in inner wall). Aneurysm and dissection often associate with bicuspid aortic valve (BAV) instead of the normal tricuspid aortic valve, and BAV aneurysms of ascending thoracic aorta have the tendency to bulge asymmetrically towards the greater curvature of aorta. Multiphoton microscopy can help us image collagen and elastin fibres, which are considered as main load-bearing constituents of the aortic wall, in order to investigate potential role of fibre microstructure in ascending thoracic aortic aneurysm or dissection. Regional differences in fibre microstructure may be driven by distinct mechanisms of vascular remodelling, and, combined with mechanical tests, could improve our understanding of the biomechanical mechanisms of aortic aneurysm and dissection potential. Should we wish to investigate the effect of microstructure in soft tissue formation and organ development, we would have to consider a rapidly growing process. In that process, the cells are the main load-bearing components, which cooperate to produce tissue-level forces that shape tissue formation. Our understanding of this phenomenon, called mechanotransduction, has advanced significantly over the past years, to the point where it is now clear that nearly every biological process is modulated by how these forces are decoded intracellularly. It is therefore important to create our own fluorescently-labeled matrix that could integrate into the tissue and enable tracking of these forces in-vivo. A new 3D optical nanomechanical biosensor (NMBS) based on fluorescent fibronectin fibres was developed based on integrated photolithography and micro-contact printing technology. NMBS was successfully validated under uniaxial tensile test of biologically relevant materials for microscopic vs. macroscopic mechanical strains. In the future, biomimetic 3D scaffolds could be fabricated by assembly of 2D fibre constructs based on the NMBS technology, in order to analyse the effect of selected set of load-bearing microstructural components on both mechanical and functional response of soft biological materials.

Comparison of macroscale and microscale mechanical properties of fresh and fixed-frozen porcine colonic tissue

Mechanical changes to the microenvironment of the extracellular matrix (ECM) in tissue have been hypothesised to elicit a pathogenic response in the surrounding cells. Hence, 3D scaffolds are a popular method of studying cellular behaviour under conditions that mimic in vivo microenvironment. To create a 3D biomimetic scaffold that captures the in vivo ECM microenvironment a robust mechanical characterisation of the whole ECM at the microscale is necessary. This study examined the multiscale methods of characterising the ECM microenvironment using porcine colon tissue. To facilitate fresh tissue microscale mechanical characterisation, a protocol for sectioning fresh, unfixed, soft biological tissue was developed. Four experiments examined both the microscale and macroscale mechanics of both fresh (Fr) and fixed-frozen (FF) porcine colonic tissue using microindentation for microscale testing and uniaxial compression testing for macroscale testing. The results obtained in this study show a significant difference in elastic modulus between Fr and FF tissue at both the macroscale and microscale. There was an order of magnitude difference between the Fr and FF tissue at the microscale between each of the three layers of the colon tested i.e. the muscularis propria (MP), the submucosa (SM) and the mucosa (M). Macroscale testing cannot capture these regional differences. The findings in this study suggest that the most appropriate method for mechanically characterising the ECM is fresh microscale mechanical microindentation. These methods can be used on a range of biological tissues to create 3D biomimetic scaffolds that are more representative of the in vivo ECM, allowing for a more in-depth characterisation of the disease process.

Tendon 3D Scaffolds Establish a Tailored Microenvironment Instructing Paracrine Mediated Regenerative Amniotic Epithelial Stem Cells Potential.

Tendon tissue engineering aims to develop effective implantable scaffolds, with ideally the native tissue’s characteristics, able to drive tissue regeneration. This research focused on fabricating tendon-like PLGA 3D biomimetic scaffolds with highly aligned fibers and verifying their influence on the biological potential of amniotic epithelial stem cells (AECs), in terms of tenodifferentiation and immunomodulation, with respect to fleeces. The produced 3D scaffolds better resemble native tendon tissue, both macroscopically, microscopically, and biomechanically. From a biological point of view, these constructs were able to instruct AECs genotypically and phenotypically. In fact, cells engineered on 3D scaffolds acquired an elongated tenocyte-like morphology; this was different from control AECs, which retained their polygonal morphology. The boosted AECs tenodifferentiation by 3D scaffolds was confirmed by the upregulation of tendon-related genes (SCX, COL1 and TNMD) and TNMD protein expression. The produced constructs also prompted AECs’ immunomodulatory potential, both at the gene and paracrine level. This enhanced immunomodulatory profile was confirmed by a greater stimulatory effect on THP-1-activated macrophages. These biological effects have been related to the mechanotransducer YAP activation evidenced by its nuclear translocation. Overall, these results support the biomimicry of PLGA 3D scaffolds, revealing that not only fiber alignment but also scaffold topology provide an in vitro favorable tenodifferentiative and immunomodulatory microenvironment for AECs that could potentially stimulate tendon regeneration.

3D Printing of PLLA/Biomineral Composite Bone Tissue Engineering Scaffolds.

Tissue engineering is one of the most effective ways to treat bone defects in recent years. However, current highly active bone tissue engineering (BTE) scaffolds are mainly based on the addition of active biological components (such as growth factors) to promote bone repair. High cost, easy inactivation and complex regulatory requirements greatly limit their practical applications. In addition, conventional fabrication methods make it difficult to meet the needs of personalized customization for the macroscopic and internal structure of tissue engineering scaffolds. Herein, this paper proposes to select five natural biominerals (eggshell, pearl, turtle shell, degelatinated deer antler and cuttlebone) with widely available sources, low price and potential osteo-inductive activity as functional particles. Subsequently compounding them into L-polylactic acid (PLLA) biomaterial ink to further explore 3D printing processes of the composite scaffold, and reveal their potential as biomimetic 3D scaffolds for bone tissue repair. The research results of this project provide a new idea for the construction of a 3D scaffold with growth-factor-free biomimetic structure, personalized customization ability and osteo-inductive activity.

Alginate functionalized biomimetic 3D scaffold improves cell culture and cryopreservation for cellular therapy

The clinical translation of cellular therapy is hampered by the scarcity of reliable and consistent cell sources. In this study, we developed an exquisite scaffold featuring the hierarchical structure and biofunctions of silkworm cocoons (CryoSiCo), for boosting cell manufacture and cryopreservation. CryoSiCo was constructed by a creative bottom-up fabrication technique integrating electrospinning, in situ surface functionalization and freeze-shaping, generating a 3D cocoon-mimicking fibrous scaffold composed of graphene oxide-incorporated polylactic acid/gelatin inner fiber core and alginate outer fiber shell. CryoSiCo provided rapid and uniform rewarming for cryopreserved cells, and maximally maintained cell viability and proliferation capability, allowing for effective cryopreservation. Importantly, CryoSiCo could cryopreserve stem cell-scaffold constructs with high cell survival and functions, which can be directly implanted to restore tissue defects. Thus, CryoSiCo represents an appealing biomimetic strategy for storing precious cells and tissue engineered constructs, showing a broad application for fundamental research and applied medicine.