Regenerative Medicine Strategies Research Articles

Development of a new electroconductive nanofibrous cardiac patch based on polyurethane-reduced graphene oxide nanocomposite scaffolds

The progress of regenerative medicine strategies for myocardial infarction will be possible with the development of biocompatible biomaterials, which not only mechanically support infarcted myocardium zone but also have the proper electrical conductivity to transfer electrical pulses. In this study, novel electroconductive nanofibrous structures based on polyurethane/reduced graphene oxide (PU/RGO) were constructed. Polyurethane solutions in two (dimethylformamide:chloroform) and three (dimethylformamide:chloroform:tetrahydrofuran) solvent systems were electrospun that resulted in different fiber diameter. Tetrahydrofuran addition decreased the PU fiber diameter about halved. Then RGO was electrosprayed as a conductive constituent simultaneously with the electrospinning of PU. PU/RGO scaffolds containing 5, 10, 15 and 20 wt percent of RGO nanosheets were fabricated by adjusting the electrospraying injection rate. Scaffolds were comparatively characterized for surface morphology, crystal structure, conductivity, wettability, chemical functional groups, mechanical properties and RGO release. Scanning electron microscope images showed strong interaction of RGO with electrospun PU. The electrical conductivity of PU/RGO meets the percolation threshold at a 15% of electrosprayed RGO (3.46 × 10−5 S/cm), converting insulating PU into a conductive nanocomposite and it achieves its maximum value for PU/RGO20 (6.05 × 10−5 S/cm). Tensile testing analysis revealed enhanced Young's modulus and the ultimate tensile strength for PU/RGO scaffolds. The biocompatibility of scaffolds was confirmed with determining the metabolic activities of exposed endothelial and myoblast cells. PU/RGO scaffolds even at high amount of RGO not only did not show cell toxicity but also enhance the cell proliferation. These findings suggest that, the PU/RGO nanofibrous scaffold can be considered as a new electroconductive cardiac patch to support myocardial regeneration.

Fetal liver development and implications for liver disease pathogenesis.

The metabolic, digestive and homeostatic roles of the liver are dependent on proper crosstalk and organization of hepatic cell lineages. These hepatic cell lineages are derived from their respective progenitors early in organogenesis in a spatiotemporally controlled manner, contributing to the liver's specialized and diverse microarchitecture. Advances in genomics, lineage tracing and microscopy have led to seminal discoveries in the past decade that have elucidated liver cell lineage hierarchies. In particular, single-cell genomics has enabled researchers to explore diversity within the liver, especially early in development when the application of bulk genomics was previously constrained due to the organ's small scale, resulting in low cell numbers. These discoveries have substantially advanced our understanding of cell differentiation trajectories, cell fate decisions, cell lineage plasticity and the signalling microenvironment underlying the formation of the liver. In addition, they have provided insights into the pathogenesis of liver disease and cancer, in which developmental processes participate in disease emergence and regeneration. Future work will focus on the translation of this knowledge to optimize in vitro models of liver development and fine-tune regenerative medicine strategies to treat liver disease. In this Review, we discuss the emergence of hepatic parenchymal and non-parenchymal cells, advances that have been made in in vitro modelling of liver development and draw parallels between developmental and pathological processes.

Bioceramic calcium phosphate-polymer scaffolds: A promising strategy for osteochondral repair and regenerative medicine

The study's objective was to fabricate a porous scaffold with desirable biological and bioactive characteristics, utilizing freeze-drying with polyvinyl alcohol (PVA). Subsequently, compressive strength tests and simulated body fluid (SBF) soaking experiments were performed to assess the mechanical and biological properties of the scaffold. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used for analyzing the scaffolds. The findings indicated that an increase in the amount of dicalcium phosphate decreased the porosity of the scaffold from 76% to 64%, raised the compressive strength from 2.48 MPa to 4.8 MPa, and lowered the dissolution rate from 39% to 24%. These changes led to an improvement in the scaffold's chemical bonding and stability. According to micromechanical models, the optimal scaffold composition was found to be 10 wt% of dicalcium phosphate in a polyvinyl alcohol mixture with constant drug content. Moreover, an increase in the dicalcium phosphate content led to an elevation in the drug release percentage due to the reduction in porosity and an increase in the drug release rate. The data were analyzed by using various kinetic models through diagrams generated by a UV device.

Extracellular vesicles: Emerged as a promising strategy for regenerative medicine.

Cell transplantation therapy has certain limitations including immune rejection and limited cell viability, which seriously hinder the transformation of stem cell-based tissue regeneration into clinical practice. Extracellular vesicles (EVs) not only possess the advantages of its derived cells, but also can avoid the risks of cell transplantation. EVs are intelligent and controllable biomaterials that can participate in a variety of physiological and pathological activities, tissue repair and regeneration by transmitting a variety of biological signals, showing great potential in cell-free tissue regeneration. In this review, we summarized the origins and characteristics of EVs, introduced the pivotal role of EVs in diverse tissues regeneration, discussed the underlying mechanisms, prospects, and challenges of EVs. We also pointed out the problems that need to be solved, application directions, and prospects of EVs in the future and shed new light on the novel cell-free strategy for using EVs in the field of regenerative medicine.

Human adipose tissue-derived small extracellular vesicles promote soft tissue repair through modulating M1-to-M2 polarization of macrophages

BackgroundSuccessful regenerative medicine strategies need the manipulation and control of macrophages’ phenotypic switching. Our previous study indicated that rat and porcine adipose tissue-derived small extracellular vesicles could successfully promote soft tissue repair. However, whether human adipose tissue-derived small extracellular vesicles (h-sEV-AT) showed the same ability to promote soft tissue regeneration and whether adipose tissue-derived small extracellular vesicles (sEV-AT) contribute to modulating the polarization of macrophages were unknown.MethodsIn this study, we, for the first time, isolated h-sEV-AT from liposuction adipose tissue and characterized the morphology, size distribution, and marker protein. In vitro, we treated adipose-derived stromal/stem cells (ASCs), endothelial cells (ECs), and M1 macrophages with h-sEV-AT. In vivo, the ability of h-sEV-AT to promote soft tissue regeneration and polarize macrophages was investigated.ResultsThe results indicated that h-sEV-AT possessed the characteristics of small extracellular vesicles (sEVs). In vitro, an obvious increase in adipogenesis and angiogenesis was induced by h-sEV-AT. In vivo, h-sEV-AT successfully induced the regeneration of adipose tissue and effectively accelerated full-thickness skin wound healing. Besides, we found that h-sEV-AT showed the ability to increase the percentage of M2 macrophages both in vivo and in vitro, which had been reported to contribute to tissue repair and regeneration.ConclusionsTaken together, these results suggested that h-sEV-AT showed the ability to induce soft tissue repair supported by not only the differentiation of ASCs and ECs but also the polarization of macrophages. Considering the abundant sources, high yield, and guaranteed effectiveness, this study provided a cell-free strategy for soft tissue regeneration that directly isolated small extracellular vesicles from human liposuction adipose tissue.

The biomimetic surface topography of Rubus fruticosus leaves stimulate the induction of osteogenic differentiation of rBMSCs

The interaction between cells and biomaterials is essential for the success of biomedical applications in which the implantation of biomaterials in the human body is necessary. It has been demonstrated that material’s chemical, mechanical, and structural properties can influence cell behaviour. The surface topography of biomaterials is a physical property that can have a major role in mediating cell–material interactions. This interaction can lead to different cell responses regarding cell motility, proliferation, migration, and even differentiation. The combination of biomaterials with mesenchymal stem cells (MSCs) for bone regeneration is a promising strategy to avoid the need for autologous transplant of bone. Surface topography was also associated with the capacity to control MSCs differentiation. Most of the topographies studied so far involve machine-generated surface topographies. Herein, our strategy differentiates from the above mentioned since we selected natural surface topographies that can modulate cell functions for regenerative medicine strategies. Rubus fruticosus leaf was the selected topography to be replicated in polycaprolactone (PCL) membranes through polydimethylsiloxane moulding and using soft lithography. Afterwards, rat bone marrow stem cells (rBMSCs) were seeded at the surface of the imprinted PCL membranes to characterize the bioactive potential of our biomimetic surface topography to drive rBMSCs differentiation into the osteogenic lineage. The selected surface topography in combination with the osteogenic inductive medium reveals having a synergistic effect promoting osteogenic differentiation.

Loss of regulation of protein synthesis and turnover underpins an attenuated stress response in senescent human mesenchymal stem cells

Cells respond to stress by synthesizing chaperone proteins that seek to correct protein misfolding and maintain function. However, abrogation of protein homeostasis is a hallmark of aging, leading to loss of function and the formation of proteotoxic aggregates characteristic of pathology. Consequently, discovering the underlying molecular causes of this deterioration in proteostasis is key to designing effective interventions to disease or to maintaining cell health in regenerative medicine strategies. Here, we examined primary human mesenchymal stem cells, cultured to a point of replicative senescence and subjected to heat shock, as an invitro model of the aging stress response. Multi -omics analysis showed how homeostasis components were reduced in senescent cells, caused by dysregulation of a functional network of chaperones, thereby limiting proteostatic competence. Time-resolved analysis of the primary response factors, including those regulating heat shock protein 70 kDa (HSPA1A), revealed that regulatory control is essentially translational. Senescent cells have a reduced capacity for chaperone protein translation and misfolded protein (MFP) turnover, driven by downregulation of ribosomal proteins and loss of the E3 ubiquitin ligase CHIP (C-terminus of HSP70 interacting protein) which marks MFPs for degradation. This limits the cell's stress response and subsequent recovery. A kinetic model recapitulated these reduced capacities and predicted an accumulation of MFP, a hypothesis supported by evidence of systematic changes to the proteomic fold state. These results thus establish a specific loss of regulatory capacity at the protein, rather than transcript, level and uncover underlying systematic links between aging and loss of protein homeostasis.

Construction, Characterization, and Regenerative Application of Self-Assembled Human Mesenchymal Stem Cell Aggregates.

Mesenchymal stem cells (MSCs), characterized by their self-renewal ability and multilineage differentiation potential, can be derived from various sources and are emerging as promising candidates for regenerative medicine, especially for regeneration of the tooth, bone, cartilage, and skin. The self-assembled approach of MSC aggregation, which notably constructs cell clusters mimicking the developing mesenchymal condensation, allows high-density stem cell delivery along with preserved cell-cell interactions and extracellular matrix (ECM) as the microenvironment niche. This method has been shown to enable efficient cell engraftment and survival, thus promoting the optimized application of exogenous MSCs in tissue engineering and safeguarding clinical organ regeneration. This paper provides a detailed protocol for the construction and characterization of self-assembled aggregates based on umbilical cord mesenchymal stem cells (UCMSCs), as well as an example of the cranial bone regenerative application. The implementation of this procedure will help guide the establishment of an efficient MSC transplantation strategy for tissue engineering and regenerative medicine.

Decellularized Tissue-Induced Cellular Recruitment for Tissue Engineering and Regenerative Medicine.

Biomaterials that recapitulate the native in vivo microenvironment are promising to facilitate tissue repair and regeneration when used in combination with relevant growth factors (GFs), chemokines, cytokines, and other small molecules and cell sources. However, limitations with the use of exogenous factors and ex vivo cell expansion has prompted cell-/GF-free tissue engineering strategies. Additionally, conventional chemotaxis assays for studying cell migration behavior provide limited information, lack long-term stability, and fail to recapitulate physiologically relevant conditions. In this study, articular cartilage tissue-based biomaterials were developed via a rapid tissue decellularization protocol. The decellularized tissue was further processed into a hydrogel through solubilization and self-assembly. Chemotactic activity of the tissue-derived gel was investigated using sophisticated cellular migration assays. These tissue-derived extracellular matrix (ECM) biomaterials retain biochemical cues of native tissue and stimulate the chemotactic migration of hBMSCs in 2D and 3D cell migration models using a real-time chemotaxis assay. This strategy, in a way, developed a new paradigm in tissue engineering where cartilage tissue repair and regeneration can be approached with decellularized cartilage tissue in the place of an engineered matrix. This strategy can be further expanded for other tissue-based ECMs to develop cell-/GF-free tissue engineering and regenerative medicine strategies for recruiting endogenous cell populations to facilitate tissue repair and regeneration.

Role of secretomes in cell-free therapeutic strategies in regenerative medicine.

After an injury, peripheral nervous system neurons have the potential to rebuild their axons by generating a complicated activation response. Signals from the damaged axon are required for this genetic transition to occur. Schwann cells (SCs) near a damaged nerve's distal stump also play a role in the local modulation of axonal programs, not only via cell-to-cell contacts but also through secreted signals (the secretome). The secretome is made up of all the proteins that the cell produces, such as cytokines, growth factors, and extracellular vesicles. The released vesicles may carry signaling proteins as well as coding and regulatory RNAs, allowing for multilayer communication. The secretome of SCs is now well understood as being critical for both orchestrating Wallerian degeneration and maintaining axonal regeneration. As a consequence, secretome has emerged as a feasible tissue regeneration alternative to cell therapy. Separate SC secretome components have been used extensively in the lab to promote peripheral nerve regeneration after injury. However, in neurological therapies, the secretome generated by mesenchymal (MSC) or other derived stem cells has been the most often used. In fact, the advantages of cell treatment have been connected to the release of bioactive chemicals and extracellular vesicles, which make up MSCs' secretome.

Unveiling the Assembly of Neutral Marine Polysaccharides into Electrostatic-Driven Layer-by-Layer Bioassemblies by Chemical Functionalization

Marine-origin polysaccharides, in particular cationic and anionic ones, have been widely explored as building blocks in fully natural or hybrid electrostatic-driven Layer-by-Layer (LbL) assemblies for bioapplications. However, the low chemical versatility imparted by neutral polysaccharides has been limiting their assembly into LbL biodevices, despite their wide availability in sources such as the marine environment, easy functionality, and very appealing features for addressing multiple biomedical and biotechnological applications. In this work, we report the chemical functionalization of laminarin (LAM) and pullulan (PUL) marine polysaccharides with peptides bearing either six lysine (K6) or aspartic acid (D6) amino acids via Cu(I)-catalyzed azide-alkyne cycloaddition to synthesize positively and negatively charged polysaccharide-peptide conjugates. The successful conjugation of the peptides into the polysaccharide's backbone was confirmed by proton nuclear magnetic resonance and attenuated total reflectance Fourier-transform infrared spectroscopy, and the positive and negative charges of the LAM-K6/PUL-K6 and LAM-D6/PUL-D6 conjugates, respectively, were assessed by zeta-potential measurements. The electrostatic-driven LbL build-up of either the LAM-D6/LAM-K6 or PUL-D6/PUL-K6 multilayered thin film was monitored in situ by quartz crystal microbalance with dissipation monitoring, revealing the successful multilayered film growth and the enhanced stability of the PUL-based film. The construction of the PUL-peptide multilayered thin film was also assessed by scanning electron microscopy and its biocompatibility was demonstrated in vitro towards L929 mouse fibroblasts. The herein proposed approach could enable the inclusion of virtually any kind of small molecules in the multilayered assemblies, including bioactive moieties, and be translated into more convoluted structures of any size and geometry, thus extending the usefulness of neutral polysaccharides and opening new avenues in the biomedical field, including in controlled drug/therapeutics delivery, tissue engineering, and regenerative medicine strategies.

Microenvironmental modulation in tandem with human stem cell transplantation enhances functional recovery after chronic complete spinal cord injury

While rapid advancements in regenerative medicine strategies for spinal cord injury (SCI) have been made, most research in this field has focused on the early stages of incomplete injury. However, the majority of patients experience chronic severe injury; therefore, treatments for these situations are fundamentally important. Here, we hypothesized that environmental modulation via a clinically relevant hepatocyte growth factor (HGF)-releasing scaffold and human iPS cell-derived neural stem/progenitor cells (hNS/PCs) transplantation contributes to functional recovery after chronic complete transection SCI. Effective release of HGF from a collagen scaffold induced progressive axonal elongation and increased grafted cell viability by activating microglia/macrophages and meningeal cells, inhibiting inflammation, reducing scar formation, and enhancing vascularization. Furthermore, hNS/PCs transplantation enhanced endogenous neuronal regrowth, the extension of graft axons, and the formation of circuits around the lesion and lumbar enlargement between host and graft neurons, resulting in the restoration of locomotor and urinary function. This study presents an effective therapeutic strategy for severe chronic SCI and provides evidence for the feasibility of regenerative medicine strategies using clinically relevant materials.

Mesenchymal stem cells express epidermal markers in an in vitro reconstructed human skin model.

Introduction: In skin traumas, such as burns, epidermal homeostasis is affected, often requiring clinical approaches. Different therapeutic strategies can be used including transplantation, besides the use of synthetic or natural materials with allogeneic cells. In this context, tissue engineering is an essential tool for skin regeneration, and using mesenchymal stem cells (MSC) from the umbilical cord appears to be a promising strategy in regenerative medicine due to its renewal and differentiation potential and hypo immunogenicity. We evaluated the transdifferentiation of MSC from umbilical cord into keratinocytes in three-dimensional (3D) in vitro skin models, using dermal equivalents composed by type I collagen with dermal fibroblasts and a commercial porcine skin decellularized matrix, both cultured at air-liquid interface (ALI). Methods: The expression of epidermal proteins cytokeratins (CK) 5, 14 and 10, involucrin and filaggrin was investigated by real-time PCR and immunofluorescence, in addition to the activity of epidermal kallikreins (KLK) on the hydrolysis of fluorogenic substrates. Results and discussion: The cultivation of MSCs with differentiation medium on these dermal supports resulted in organotypic cultures characterized by the expression of the epidermal markers CK5, CK14, CK10 and involucrin, mainly on the 7th day of culture, and filaggrin at 10th day in ALI. Also, there was a 3-fold increase in the KLK activity in the epidermal equivalents composed by MSC induced to differentiate into keratinocytes compared to the control (MSC cultivated in the proliferation medium). Specifically, the use of collagen and fibroblasts resulted in a more organized MSC-based organotypic culture in comparison to the decellularized matrix. Despite the non-typical epithelium structure formed by MSC onto dermal equivalents, the expression of important epidermal markers in addition to the paracrine effects of these cells in skin may indicate its potential use to produce skin-based substitutes.

Platelet-rich Fibrin versus Platelet-rich Plasma: A Study to Assess Efficacy as a Regenerative Medicine Strategy for Chronic Cutaneous Ulcers.

The management of nonhealing ulcers has been a major challenge clinically. Current therapies include debridement, offloading, etc., which show a poor response. Newer modalities include stem cells, platelet-derived growth factors, and fibrin glues, which reduce healing time. Platelets play a major role in wound healing through the secretion of growth factors, chemokines, etc. and have been an area of interest as a modality in regenerative medicine. The aim was to study the comparative efficacy of autologous platelet-rich fibrin (PRF) and platelet-rich plasma (PRP) as a regenerative medicine strategy for chronic cutaneous ulcers. Forty-four ulcers of duration greater than six weeks were enrolled for a comparative study comprising two groups, each divided either into group A receiving PRF dressings or group B receiving PRP dressing for six weeks. The ulcer evaluation was performed at baseline, each weekly dressing, and a two-week follow-up. Primary efficacy was assessed by the percentage reduction in the volume of ulcers and re-epithelization at eight weeks. In total, 95.2% of ulcers in group A and 90.4% of ulcers in group B showed complete re-epithelization. One ulcer in group A and two ulcers in group B developed an infection. The recurrence of the ulcer was seen in four ulcers in the PRF group and three ulcers in the PRP group. Dressings done with PRF and PRP showed similar efficacy in the percentage reduction in the volume and re-epithelization of chronic cutaneous ulcers. Both dressings were associated with similar complications. PRF and PRP dressings provide a safe, efficacious, and inexpensive regenerative medicine strategy in the healing of chronic cutaneous ulcers.

Clinical usage of dental stem cells and their derived extracellular vesicles.

Stem cell-based therapies remain at the forefront of tissue engineering and regenerative medicine because stem cells are a unique cell source with enormous potential to treat incurable diseases and even extend lifespans. The search for the best stem cell candidates continues to evolve and in recent years, dental stem cells have received significant attention due to their easy accessibility, high plasticity, and multipotential properties. Dental stem cells have been the subject of extensive research in both animal models and human clinical trials over the past two decades, and have demonstrated significant potential in ocular therapy, bone tissue engineering, and, of course, therapeutic applications in dentistry such as regenerative endodontics and periodontal tissue regeneration. These new sources of cells may be advantageous for cellular therapy and the advancement of regenerative medicine strategies, such as allogeneic transplantation or therapy with extracellular vesicles (EVs), which are functional nanoscale membrane vesicles produced by cells. This chapter discusses the accumulating research findings on cell-based regenerative therapy utilizing dental stem cells and their derived EVs, which could be a viable tool for the treatment of a variety of diseases and hence extremely valuable to mankind in the long run.

Regenerative medicine: going beyond transplantology

Since the possibilities of transplantology are limited, there is a need for tissue engineering and regenerative medicine (RM). Several high-tech approaches are used in RM: the use of soluble molecules, gene therapy, stem cell transplantation, tissue engineering, reprogramming of cells and tissues, etc. As an important component, RM strategies include innovative materials that can imitate the extracellular matrix of tissues, influencing the behavior of cells and regulating the structure and function of the formed tissue, for example, 3D polymer scaffolds, bioglass grafts, and nanofiber meshes. There is also no-scaffold tissue engineering, for example, the formation of cell sheets and the cultivation of cells capable of self-organization into appropriate sub-organ structures (intestinal crypts, kidney nephrons, and lung alveoli). In the direction of cell-free RM, the attention of scientists is attracted by exosomes – microvesicles of cellular origin sized 40-100 nm. They can carry a “cargo” of proteins, lipids, RNA, and DNA. Exosomes have the potential for use in the treatment of neurodegenerative, infectious, musculoskeletal, and cardiovascular diseases. Due to their physiological nature, exosomes have very low immunogenicity and the potential to pass through the blood-brain barrier. For the further development of exosomal therapy, it is necessary to improve the methods of their isolation and purification, as well as research on efficiency, safety, pharmacokinetics and pharmacodynamics. An important source of cells for RM is represented by mesenchymal stem cells, which are able to differentiate into almost any cell line and exert anti-inflammatory, immunoregulatory and immunosuppressive effects.

Stem cell-derived exosomes in the treatment of melasma and its percutaneous penetration.

Melasma is a refractory skin disease due to its complex pathogenesis and difficult treatment. Studies have found that human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exos) could serve as a novel cell-free therapeutic strategy in regenerative and esthetic medicine. It could potentially treat melasma, but the skin barrier is a challenge. In this study, we aim to explore the safety and efficacy of hUCMSC-Exos in the treatment of melasma and the means to promote its percutaneous penetration. In the animal study about the effect of penetration, percutaneous penetration of PKH67-labeled hUCMSC-Exos was studied under microneedles, 1565 nm nonablative fractional laser (NAFL), and a plasma named Peninsula Blue Aurora Shumin Master (PBASM) treatments, observed by confocal laser scanning microscopy. In the clinical application study, 60 patients with melasma treated in our department were divided into four groups. NAFL combined with normal saline treatment was used for Group A. Microneedles, NAFL, and PBASM combined with hUCMSC-Exos treatments were used for Groups B, C, and D, respectively. Each patient received four treatments at 1-month intervals. Assessments were done using the degree of pain posttreatment, melasma area and severity score, improvement rate, physician global assessment score, satisfaction, and complications. In the animal study about the effect of penetration, hUCMSC-Exos can penetrate the deep dermis under microneedles, NAFL, and PBASM treatments. In the clinical application study, compared with Group A, Groups B, C, and D showed significantly improved therapeutic effect and patient satisfaction (p < 0.05), and there was no significant difference among Groups B, C, and D.(p > 0.05). Patients in Group B reported higher pain levels than those in the other three groups (p < 0.05); the treatment experience of patients in Group D was better. hUCMSC-Exos can improve the symptoms of melasma safely and effectively. Compared with microneedles, NAFL and PBASM can also achieve a good effect toward promoting penetration. These findings are worthy of exploration and clinical application.

Hydrogel viscoelasticity modulates migration and fusion of mesenchymal stem cell spheroids.

Multicellular spheroids made of stem cells can act as building blocks that fuse to capture complex aspects of native in vivo environments, but the effect of hydrogel viscoelasticity on cell migration from spheroids and their fusion remains largely unknown. Here, we investigated the effect of viscoelasticity on migration and fusion behavior of mesenchymal stem cell (MSC) spheroids using hydrogels with a similar elasticity but different stress relaxation profiles. Fast relaxing (FR) matrices were found to be significantly more permissive to cell migration and consequent fusion of MSC spheroids. Mechanistically, inhibition of ROCK and Rac1 pathways prevented cell migration. Moreover, the combination of biophysical and biochemical cues provided by fast relaxing hydrogels and platelet-derived growth factor (PDGF) supplementation, respectively, resulted in a synergistic enhancement of migration and fusion. Overall, these findings emphasize the important role of matrix viscoelasticity in tissue engineering and regenerative medicine strategies based on spheroids.

Rapid fabrication and screening of tailored functional 3D biomaterials: Validation in bone tissue repair – Part II

Regenerative medicine strategies place increasingly sophisticated demands on 3D biomaterials to promote tissue formation at sites where tissue would otherwise not form. Ideally, the discovery/fabrication of the 3D scaffolds needs to be high-throughput and uniform to ensure quick and in-depth analysis in order to pinpoint appropriate chemical and mechanical properties of a biomaterial. Herein we present a versatile technique to screen new potential biocompatible acrylate-based 3D scaffolds with the ultimate aim of application in tissue repair. As part of this process, we identified an acrylate-based 3D porous scaffold that promoted cell proliferation followed by accelerated tissue formation, pre-requisites for tissue repair. Scaffolds were fabricated by a facile freeze-casting and an in-situ photo-polymerization route, embracing a high-throughput synthesis, screening and characterization protocol. The current studies demonstrate the dependence of cellular growth and vascularization on the porosity and intrinsic chemical nature of the scaffolds, with tuneable 3D scaffolds generated with large, interconnected pores suitable for cellular growth applied to skeletal reparation. Our studies showed increased cell proliferation, collagen and ALP expression, while chorioallantoic membrane assays indicated biocompatibility and demonstrated the angiogenic nature of the scaffolds. VEGRF2 expression in vivo observed throughout the 3D scaffolds in the absence of growth factor supplementation demonstrates a potential for angiogenesis. This novel platform provides an innovative approach to 3D scanning of synthetic biomaterials for tissue regeneration.

A Comprehensive Review of Electrospun Fibers, 3D-Printed Scaffolds, and Hydrogels for Cancer Therapies.

Anticancer therapies and regenerative medicine are being developed to destroy tumor cells, as well as remodel, replace, and support injured organs and tissues. Nowadays, a suitable three-dimensional structure of the scaffold and the type of cells used are crucial for creating bio-inspired organs and tissues. The materials used in medicine are made of non-degradable and degradable biomaterials and can serve as drug carriers. Developing flexible and properly targeted drug carrier systems is crucial for tissue engineering, regenerative medicine, and novel cancer treatment strategies. This review is focused on presenting innovative biomaterials, i.e., electrospun nanofibers, 3D-printed scaffolds, and hydrogels as a novel approach for anticancer treatments which are still under development and awaiting thorough optimization.