Regenerative Medicine Applications Research Articles

3D bio-printed scaffolds and smart implants: evaluating functional performance in animal surgery models

Surgical models with an application of 3D bio-printed scaffolds and smart implants in animal surgery and their further applicability in regenerative medicine and implantology. This review discusses the functional performance of these advanced biomaterials in terms of mechanical properties, biodegradation rates, cellular responses, and in vivo integration. These 3D bio-printed scaffolds from hydrogels, bioceramics, and polymer composites feature tunable porosity (50–90%), mechanical strengths (0.1–50 MPa) and degradation rates compatible with bone, cartilage, and soft tissue engineering. Smart implants combining biosensors, drug delivery systems, and electrical stimulation in real time facilitate island operation of tissue regeneration. According to animal studies, titanium-based smart implants with surface-modified coatings show 86% osseointegration enhancement. In a rabbit knee model, gelatin-methacryloyl (GelMA) scaffolds for cartilage repair restored over 75% of native tissue function within 12 weeks. In rodent sciatic nerve defects, electrostimulated bio-scaffolds have induced a 40% increase in the rate of nerve regeneration. Concerning challenges, such as immune rejection and vascularization limitation, in addition to the demand for long-term stability, still require further improvements, including enhanced resolution of bioprinting technology and bioactive material offer. This review provides a critical assessment of qualitative and quantitative evidence to drive preclinical and translational studies in the wider context of precision medicine and next-generation, implantable biomaterials.

Genetically modified cell membrane proteins in tissue engineering and regenerative medicine.

Genetically modified cell membrane proteins can effectively regulate cell proliferation and differentiation, while also integrating novel biomaterials. As a promising biomedical tool, this technology has broad applications in tissue engineering and regenerative medicine. Both viral and non-viral gene transfection methods have been employed to create genetically modified cell membrane proteins. Numerous studies have demonstrated the significant efficacy of genetically modified cell membrane proteins in promoting bone regeneration, treating cardiovascular diseases, aiding lung injury recovery, advancing immunotherapy, and in applications involving engineered cell membrane sheets and cell spheroids. However, this technology faces several limitations, including biosafety and ethical concerns associated with genetic modification. This article summarizes recent advances in genetically modified cell membrane proteins, detailing their preparation, applications, limitations, and future directions.

Acrylated Bioengineered Mussel Protein-Based Adhesive Nanoparticles for Locoregional and Sustained Drug Delivery.

Nanoparticles have emerged as promising drug carriers owing to their ability to permeate cell membranes and enhance drug stability. However, their clinical application faces significant challenges, including rapid diffusion, inefficient retention at target sites, and burst drug release. This study proposes the use of adhesive nanoparticles derived from acrylated bioengineered mussel adhesive proteins (MAPs). Acrylic groups were conjugated to lysine residues in MAPs to form polyacrylate-MAPs by photo-cross-linking, retaining sufficient 3,4-dihydroxyphenylalanine residues for strong tissue adhesion in aqueous environments. These nanoparticles were designed to adhere effectively to the administration sites and facilitate continuous drug release. In vitro and in vivo evaluations demonstrated that the acrylated MAP-based nanoparticles exhibited superior wet adhesive properties, sustained drug release, and long-term retention at the administration site and effectively suppressed tumor growth, ensuring that a single dose maintained a therapeutic concentration at the target site over extended periods. Thus, this approach could address the challenges of drug localization and retention, significantly improving therapeutic efficacy. This study emphasizes the versatility of bioengineered MAP-based adhesive nanoparticles for locoregional and sustained drug delivery, with promising applications in cancer therapy, regenerative medicine, and other biomedical fields.

Molecular Mechanisms of Stem Cell Aging and Their Challenges and Applications in Regenerative Medicine

Stem cell aging is a complex biological process characterized by diminished self-renewal capacity and impaired differentiation potential, directly contributing to decreased tissue regeneration and age-related diseases. This review systematically examines the molecular mechanisms underlying stem cell aging, including telomere shortening, DNA damage accumulation, metabolic imbalance, mitochondrial dysfunction, epigenetic modifications, and inflammatory responses. These interconnected mechanisms form a complex regulatory network driving stem cell functional decline. The challenges posed by stem cell aging to regenerative medicine are substantial: aging reduces tissue regenerative capacity across hematopoietic, neural, and muscular systems, limits the efficacy of stem cell transplantation due to poor survival rates and altered differentiation bias, and increases the risk of malignant transformation. To address these challenges, researchers have developed various intervention strategies, including cell reprogramming technology, gene editing approaches, metabolic regulation, antioxidant therapies, exosome applications, and microenvironment optimization. While significant progress has been made, challenges remain, particularly regarding off-target effects in gene editing, dose-dependent toxicity in metabolic regulation, and standardization issues in exosome production. Future research directions include developing aging-specific biomarkers for precision intervention, analyzing tissue-specific aging mechanisms, and exploring metabolism-epigenetic-immunity regulatory networks. The advancement of stem cell aging intervention has profound implications for both regenerative medicine and anti-aging therapies, offering promising approaches to address age-related diseases and improve quality of life.

Acoustic holographic assembly of cell-dense tissue constructs.

Tissue engineering aims to develop tissue constructs as models or substitutes for native tissues. For organ-level biological studies and regenerative medicine applications, it is essential to fabricate tissue constructs with physiologically relevant cell densities (on the order of 10 million to 1 billion cells·mL-1, large size (centimeter scale and larger), and a controllable geometry to guide tissue maturation. State-of-the-art biofabrication methods, however, struggle to simultaneously meet all of these demands. The recently proposed acoustic holographic assembly (AHA) method shows promise, as it is compatible with culture media and enables the contactless, label-free, and volumetric assembly of biological cells in a predefined geometry within few minutes. Here we present an AHA biofabrication scheme designated for fabricating cell-dense, centimeter-scale, and arbitrarily-shaped tissue constructs using a compact benchtop instrument compatible with a biolab environment. We demonstrate the assembly of C2C12 myoblasts in gelatin methacryloyl (GelMA) into large and asymmetric branch-shaped constructs, which are rapidly formed with an average cell density of 40 million cells·mL-1and a local density of up to 260 million cells·mL-1. Featuring a high viability of 90.5%±4.3%, the assembled cell constructs are observed to grow within the GelMA hydrogel under perfusion over five days. Further, we show how AHA can --- in a single step --- assemble cells into layered and three-dimensional geometries inside standard cell culture labware. It can therefore help obtain engineered tissue constructs with structural and functional characteristics seen in more complex native tissues.

Emerging Frontiers in Zebrafish Embryonic and Adult-Derived Cell Lines

Zebrafish (Danio rerio) has become a pivotal vertebrate model in biomedical research, renowned for its genetic similarity to humans, optical transparency, rapid embryonic development, and amenability to experimental manipulation. In recent years, the derivation of cell lines from zebrafish embryos has unlocked new possibilities for in vitro studies across developmental biology, toxicology, disease modeling, and genetic engineering. These embryo-derived cultures offer scalable, reproducible, and ethically favorable alternatives to in vivo approaches, enabling high-throughput screening and mechanistic exploration under defined conditions. This review provides a comprehensive overview of protocols for establishing and maintaining zebrafish embryonic cell lines, emphasizing culture conditions, pluripotency features, transfection strategies, and recent innovations such as genotype-defined mutant lines generated via CRISPR/Cas9 and feeder-free systems. We also highlight emerging applications in oncology, regenerative medicine, and functional genomics, positioning zebrafish cell lines as versatile platforms bridging animal models and next-generation in vitro systems. Its continued optimization holds promise for improved reproducibility, reduced animal use, and expanded translational impact in biomedical research.

Application of decellularized tissues in ear regeneration.

Application of decellularized tissues in ear regeneration.

Menstrual Blood and Endometrial Mesenchymal Stem/Stromal Cells: A Frontier in Regenerative Medicine and Cancer Therapy.

Menstrual Blood and Endometrial Mesenchymal Stem/Stromal Cells: A Frontier in Regenerative Medicine and Cancer Therapy.

Effects of PDMS Culture on Stem Cell Differentiation Towards Definitive Endoderm and Hepatocytes.

Effects of PDMS Culture on Stem Cell Differentiation Towards Definitive Endoderm and Hepatocytes.

Self-assembled organoid-tissue modules for scalable organoid engineering: Application to chondrogenic regeneration.

Self-assembled organoid-tissue modules for scalable organoid engineering: Application to chondrogenic regeneration.

Application of Platelet-Rich Plasma-Based Scaffolds in Soft and Hard Tissue Regeneration.

Platelet-rich plasma (PRP) is a blood product with higher platelet concentrations than whole blood, offering controlled delivery of growth factors (GFs) for regenerative medicine. PRP plays pivotal roles in tissue restoration mechanisms, including angiogenesis, fibroblast proliferation, and extracellular matrix development, making it applicable across various regenerative medicine treatments. Despite promising results in different tissue injuries, challenges such as short half-life and rapid deactivation by proteases persist. To address these challenges, biomaterial-based delivery scaffolds, such as sponges or hydrogels, have been investigated. Current studies exhibit that PRP-loaded scaffolds fix these issues due to the sustained release of GFs. In this regard, given the widespread application of PRP in clinical studies, the use of PRP-loaded scaffolds has drawn significant consideration in tissue engineering (TE). Therefore, this review briefly introduces PRP as a rich origin of GFs, its classification, and preparation methods and discusses PRP applications in regenerative medicine. This study also emphasizes and reviews the latest research on the using scaffolds for PRP delivery in diverse fields of TE, including skin, bone, and cartilage repair.

Collagen Nanofiber Reinforced Alginate Hydrogel Tube Microbioreactors for Cell Culture.

The large-scale production of mammalian cells is pivotal for various applications; however, current bioreactor technologies encounter significant technical and economic challenges. Scaling up cell cultures remains problematic due to excessive cell aggregation, shear stress-induced cell death, batch-to-batch inconsistencies, and limited scalability. We propose that engineering a cell-friendly microenvironment can enhance culture efficiency. Previously, we developed alginate hydrogel microtubes (AlgTubes) that significantly improved cell density and growth rates. Nevertheless, AlgTubes lack adhesion sites essential for anchorage-dependent cells and frequently break, causing cell leakage and production inconsistencies. To address these limitations, this study reinforced AlgTubes with collagen nanofibers, creating collagen-alginate hybrid hydrogel microtubes (ColAlgTubes). Utilizing a novel micro-extruder, we efficiently produced cell-loaded ColAlgTubes. Collagen formed a dense nanofiber network interwoven with the alginate mesh, enhancing the hydrogel's mechanical properties while providing cell adhesion sites. ColAlgTubes protected cells from hydrodynamic stress and maintained cell mass within a 400 μm diameter, ensuring efficient nutrient exchange and waste removal. This optimized microenvironment resulted in high cell viability, rapid proliferation, and exceptional yields of 5×10 8 cells/mL - 200 times higher than conventional culture methods. With their scalability, cost-effectiveness, and efficiency, ColAlgTubes offers a transformative solution for large-scale cell production with broad applications in biotechnology, regenerative medicine, and therapeutic manufacturing.

Flow Cytometry Illuminates Dental Stem Cells: a Systematic Review of Immunomodulatory and Regenerative Breakthroughs.

Dental stem cells hold significant potential in regenerative medicine due to their multipotency, accessibility, and immunomodulatory effects. Flow cytometry is a critical tool for analyzing these cells, particularly in identifying and characterizing immunomodulatory markers that enhance their clinical applications. This systematic review aims to answer the question:"How does flow cytometry facilitate the identification and characterization of immunomodulatory markers in dental stem cells to enhance their application in regenerative medicine?". An exhaustive literature search was conducted in PubMed, retrieving 430 studies, of which 284 met inclusion criteria. Studies were selected based on the use of flow cytometry to analyze immunomodulatory markers in dental stem cells, focusing on methodologies, key findings, and challenges. Of the 284 articles, 229 employed flow cytometry, with 115 reporting relevant results. Flow cytometry revealed important insights into the immunological interactions of various dental stem cells, including dental pulp stem cells, stem cells from human exfoliated deciduous teeth, periodontal ligament stem cells, and stem cells from the apical papilla, by identifying and characterizing immunomodulatory markers such as PD-L1, IDO, and TGF-β1. Flow cytometry is essential for advancing the understanding of dental stem cells' immunomodulatory properties. Standardization of methodologies is required to overcome technical challenges and enhance the clinical applications of dental stem cells in regenerative medicine and immunotherapy.

Efficient spheroid morphology assessment with a ChatGPT data analyst: implications for cell therapy.

Adipose-derived stem cells (ADSCs) exhibit promising potential for the treatment of various diseases, including osteoarthritis. Spheroids derived from ADSCs are a viable treatment option with enhanced anti-inflammatory effects and tissue repair capabilities. SphereRing® is a rotating donut-shaped tube that efficiently produces large quantities of spheroids. However, accurately measuring spheroid size for spheroid quality assessment is challenging. This study aimed to develop an automated method for measuring spheroid size using deep learning through the ChatGPT Data Analyst for image recognition and processing. The area, perimeter, and circularity of spheroids generated with the SphereRing system were analyzed using ChatGPT Data Analyst and ImageJ. Measurement accuracy was validated using Bland-Altman analysis and scatter plot correlation coefficients. ChatGPT Data Analyst was consistent with ImageJ for all parameters. Bland-Altman plots demonstrated strong agreement; most data points were within the 95% limits. The ChatGPT Data Analyst provides a reliable and efficient alternative for assessing spheroid quality. This method reduces human error and improves reproducibility to enhance spheroid quality control. Thus, this method has potential applications in regenerative medicine.

Integrating Miniaturized Turbines into Microfluidic Droplet Generating Systems for Scalable Microgel Production.

Generating microgels is of critical importance in developing granular biomaterials, which have diverse emerging applications in regenerative medicine and tissue engineering. However, producing large volumes of microgels while maintaining a reasonably low population of polydispersity remains a challenge. Here, we introduce the Turbinator, a device that can be added on to the commercially available Shirasu Porous Glass (SPG) microdroplet production system to provide precise control of the local shear stresses around the porous glass droplet production head. In addition to reducing the polydispersity of droplet sizes produced using the SPG, this system allows for continuous production of droplets in inexpensive and massively scalable kerosene oil baths for industrial manufacturing applications. To validate the device, we develop finite element models to understand the local shear stresses applied and characterize the droplets produced under various operating conditions. Finally, we confirmed that this production method supports biological activity via viability and spreading assays of fibroblast cells and invasion assays in a model cancer spheroid system.

Unlocking the Power of Electrospinning: A Review of Cutting-Edge Polymers and their Impact on Scaffold Design and Performance.

Electrospun scaffolds are pivotal in tissue engineering due to their ability to mimic the Extracellular Matrix (ECM). Despite their potential, challenges such as, two-dimensional structure, limited load bearing capacity, and low mechanical strength restrict their application. This review explores advancements in electrospinning techniques and materials, highlighting methods like coaxial electrospinning, which enables the encapsulation of therapeutic agents, and the integration with 3D printing to create hybrid scaffolds with improved cell infiltration. Characterization techniques assessed by different researchers, such as scaffold morphology, mechanical properties, and biocompatibility, show that scaffolds with high spatial interconnectivity and controlled alignment enhance cell orientation and migration. Innovations in smart polymers and stimuli-responsive materials have furthered scaffold functionality. While recent advancements address some limitations, issues with scalability and production uniformity remain. Future research should optimize fabrication parameters and explore novel materials to enhance scaffold performance, requiring collaborative efforts and technological innovations to expand their practical applications in tissue engineering and regenerative medicine.

Imine Crosslinked, Injectable, and Self-Healing Fucoidan Hydrogel with Immunomodulatory Properties.

Biomaterials with inherent anti-inflammatory properties and the ability to foster a pro-regenerative environment hold significant promise for enhancing cell transplantation and tissue regeneration. Fucoidan, a sulfated polysaccharide with well-documented immune-regulatory and antioxidant capabilities, offers strong potential for creating such biomaterials. Yet, there is a lack of engineered fucoidan hydrogels that are injectable and provide tunable physicochemical properties. In this study, the ability of fucoidan to undergo periodate-mediated oxidation is leveraged to introduce aldehydes into backbone (oxidized fucoidan, OFu), enabling the formation of reversible, imine-crosslinks with amine-containing molecules such as gelatin. The imine-crosslinked OFu-gelatin hydrogel provided excellent control over gelation rate and mechanical properties. Counter-intuitively, OFu-gelatin hydrogel exhibited excellent long-term stability (≥28 days), even though imine crosslinks are known to be relatively less stable. Moreover, the OFu-gelatin hydrogels are self-healing, injectable, and biocompatible, supporting cell culture and encapsulation. Furthermore, fucoidan hydrogels displayed immune-modulatory properties both in vitro and in vivo. This innovative injectable fucoidan hydrogel presents a versatile platform for applications in tissue engineering and regenerative medicine.

Impacts of Inorganic Arsenic Exposure on Genetic Stability of Human Mesenchymal Stromal Cells.

Human mesenchymal stem/stromal cells (hMSCs) can differentiate into mesoderm-type cells, making them suitable candidates for tissue repair therapies. However, their relatively low frequency in adult tissue necessitates exvivo expansion prior to regenerative medicine applications, and therefore, long-term hMSC genetic stability during expansion should be studied. hMSC applications in regenerative medicine ensure commercial availability of normal karyotype human primary cells for toxicity assessment and hMSCs could serve as alternatives to immortalized human cell models. In this work, we evaluated the potential of hMSCs in toxicity testing using inorganic arsenic (iAs) as a case study. hMSCs were exposed to iAs at different durations to track cellular aging and study long-term genetic stability. iAs exposures (48 h) resulted in micronuclei induction. hMSCs were also exposed to iAs for 6 days to determine if hMSCs would become more susceptible to chromosomal damage following exposure to the model genotoxicant, mitomycin C (MMC). The culture duration and iAs exposure did not alter MMC potency, indicating that the hMSC susceptibility to chromosomal damage remained unchanged. We also used gene expression analysis to investigate the molecular impacts of iAs on hMSCs over the course of short (3 days total) and long (30 days total) experiments. Both iAs exposures activated biomarkers associated with oxidative stress, but not biomarkers for direct DNA damage, providing support for an indirect mode of action for iAs genotoxicity. Overall, this study establishes the utility of hMSCs as a new model for toxicity screening and provides mechanistic information underlying iAs toxicity.

A Comprehensive Review of Bioactive Glasses: Synthesis, Characterization, and Applications in Regenerative Medicine

A Comprehensive Review of Bioactive Glasses: Synthesis, Characterization, and Applications in Regenerative Medicine

3D (Bio) Printing Combined Fiber Fabrication Methods for Tissue Engineering Applications: Possibilities and Limitations

AbstractBiofabrication is an emerging interdisciplinary field of engineering that aims to develop technologies for applications in tissue engineering and regenerative medicine. A progressing biofabrication technology is 3D (bio) printing (3DBP), which allows for controlled spatial deposition of cell‐laden bioinks in a layer‐by‐layer approach to fabricate biologically active constructs. Although 3DBP can create some biologically relevant structures, it uses hydrogels, which are isotropic in nature and do not provide sufficient mechanical properties to reconstruct many tissues, such as cartilage, bone, and skin. Additionally, hydrogels alone do not replicate the complex hierarchical buildup of native tissue extracellular matrix (ECM), which contains both gel‐like and fibrous components. Replicating native tissue's structure both mechanically and biologically by incorporating fibers would result in enhanced biological performance. This is possible by integrating biofabrication technologies such as 3DBP and fiber fabrication techniques. Thus, harnessing the strengths of each technique and eliminating their limitations. This will enable the fabrication of hybrid 3D constructs with multiscale hierarchy and enhanced mechanical and biological performance comparable to native tissue. This review aims to highlight attempts to combine fiber fabrication methods with 3DBP for tissue engineering applications. Additionally, different fiber fabrication techniques are discussed, showcasing their limitations and possible integration with 3DBP.