Tissue Engineering Technology Research Articles

Conductive Biocomposite Made by Two-Photon Polymerization of Hydrogels Based on BSA and Carbon Nanotubes with Eosin-Y

Currently, tissue engineering technologies are promising for the restoration of damaged organs and tissues. For regeneration of electrically conductive tissues or neural interfaces, it is necessary to provide electrical conductivity for the transmission of electrophysiological signals. The developed biocomposite structures presented in this article possess such properties. Their composition includes bovine serum albumin (BSA), gelatin, eosin-Y and single-walled carbon nanotubes (SWCNTs). For the first time, a biocomposite structure was formed from the proposed hydrogel using a nanosecond laser, and a two-photon absorption cross section value of 580 GM was achieved. Increased viscosity over 3 mPa∙s and self-focusing with a nonlinear refractive index of 42 × 10−12 cm2/W make it possible to create a biocomposite structure over the entire specified area. The obtained electrical conductivity value was 19 mS∙cm−1, due to the formation of effective electrically conductive networks. For a biocomposite with a concentration of gelatin 3 wt. %, formed by low-energy near-IR pulses, the survival of Neuro 2A nerve tissue cells was confirmed. The obtained results are important for the creation of new tissue engineering structures and neural interfaces from a biopolymer hydrogel based on the organic dye eosin-Y and carbon nanotubes by two-photon polymerization.

Numerical Analysis of the Cell Droplet Loading Process in Cell Printing

Cell printing is a promising technology in tissue engineering, with which the complex three-dimensional tissue constructs can be formed by sequentially printing the cells layer by layer. Though some cell printing experiments with commercial inkjet printers show the possibility of this idea, there are some problems, such as cell damage due the mechanical impact during cell direct writing, which include two processes of cell ejection and cell landing. Cell damage observed during the bioprinting process is often simply attributed to interactions between cells and substrate. However, in reality, cell damage can also arise from complex mechanical effects caused by collisions between cell droplets during continuous printing processes. The objective of this research is to numerically simulate the collision effects between continuously printed cell droplets within the bioprinting process, with a particular focus on analyzing the consequent cell droplet deformation and stress distribution. The influence of gravity force was ignored, cell droplet landing was divided into four phases, the first phase is cell droplet free falling at a certain velocity; the second phase is the collision between the descending cell droplet and the pre-existing cell droplets that have been previously printed onto the substrate. This collision results in significant deformation of the cell membranes of both cell droplets in contact; the third phase is the cell droplet hitting a rigid body substrate; the fourth phase is the cell droplet being bounced. We conducted a qualitative analysis of the stress and strain of cell droplets during the cell printing process to evaluate the influence of different parameters on the printing effect. The results indicate that an increase in jet velocity leads to an increase in stress on cell droplets, thereby increasing the probability of cell damage. Adding cell droplet layers on the substrate can effectively reduce the impact force caused by collisions. Smaller droplets are more susceptible to rupture at higher velocities. These findings provide a scientific basis for optimizing cell printing parameters.

Evaluation of Post-Processing on Additive Manufactured Bioresorbable Polymers for Medical Devices.

Additive manufacturing (AM) has seen massive growth in the medical device sector and an increase in the clearance of devices. Many challenges still exist in the design, development, and clinical use of AM-fabricated devices, notably the processing, annealing, and sterilization of resorbable polymers. In addition, the use of these materials continues to grow in medical devices and scaffold technologies for tissue engineering and regenerative medicine (TERM). Specifically, this study focused on the scaffold mechanical properties post-processing and throughout a simulated resorption (in vitro) study. Herein, we evaluated three (3) materials that span a range of mechanical properties and degradation rates relating to a range of tissue healing rates and mechanical properties affording the opportunity of biomimetic potentials, Caproprene 100M, Lactoflex 7415, and Lactoprene 100M. These bioresorbable polymers were additively manufactured into scaffold forms of Type V tensile bars to investigate post-processing parameters. A range of heat treatments were then performed after the AM process to induce a range of semicrystalline morphologies, and subsequently, two different sterilization techniques were performed, one based on super critical carbon dioxide and another using electron beam radiation. It was statistically shown that the heat treatment parameters and the sterilization method had statistically significant effects on the scaffold properties of each material. While material differences were responsible for the majority of the mechanical property breadth, techniques utilizing analysis of variance allowed the observation of significant effects and interactions associated with heat treatment, sterilization, and material parameters (alpha = 0.05). The characterization of the sample groups provided insight into the process-structure-property-performance relationships of the resorbable scaffold samples. It was established that the post-processing impacted the scaffold structures, and therefore, sterilization and heat treatment selections should be included within initial design considerations alongside material selection as critical for device development, especially when AM bioresorbable scaffolds for TERM.

The Application of Biomaterial-Based Spinal Cord Tissue Engineering.

Advancements in biomaterial-based spinal cord tissue engineering technology have profoundly influenced regenerative medicine, providing innovative solutions for both spinal cord organoid development and engineered spinal cord injury (SCI) repair. In spinal cord organoids, biomaterials offer a supportive microenvironment that mimics the natural extracellular matrix, facilitating cell differentiation and organization and advancing the understanding of spinal cord development and pathophysiology. Furthermore, biomaterials are essential in constructing engineered spinal cords for SCI repair. The incorporation of biomaterials with growth factors, fabrication of ordered scaffold structures, and artificial spinal cord assemblies are critical insights for SCI to ensure structural integrity, enhance cell viability, and promote neural regeneration in transplantation. In summary, this review summarizes the contribution of biomaterials to the spinal cord organoids progression and discusses strategies for biomaterial-based spinal cord engineering in SCI therapy. These achievements underscore the transformative potential of biomaterials to improve treatment options for SCI and accelerate future clinical applications.

Effective and new technologies in kidney tissue engineering.

Kidney disease encompasses a wide spectrum of conditions, ranging from simple infections to chronic kidney disease. When the kidneys are unable to filter blood and remove waste products, these abnormalities can lead to kidney failure. In severe cases of kidney failure, kidney transplantation is considered the only definitive treatment. Worldwide, the World Health Organization (WHO) repeatedly emphasizes the importance of organ donation and increasing transplantation rates. Many countries implement national programs to promote the culture of organ donation and improve patient access to kidney transplantation. The extent to which this procedure is performed varies across countries and is influenced by several factors, including the volume of organ donation, medical infrastructure, access to technology and health policies. However, a kidney transplant comes with challenges and problems that impact its success. Kidney tissue engineering is a new approach that shows promise for repairing and replacing damaged kidney tissue. This article reviews recent advances in kidney tissue engineering, focusing on engineered structures such as hydrogels, electrospinning, 3D bioprinting, and microfluidic systems. By mimicking the extracellular environment of the kidney, these structures provide suitable conditions for the growth and development of kidney cells. The role of these structures in the formation of blood vessels, the mimicry of kidney functions and the challenges in this field were also discussed. The results of this study show that kidney tissue engineering has high potential for treating kidney diseases and reducing the need for kidney transplantation. However, to achieve clinical application of this technology, further research is required to improve the biocompatibility, vascularization and long-term performance of engineered tissues.

Meniscal scaffolds based on self-healable elastomer-hydrogel composites with biomimetic structure and tribological properties for repairing meniscal injuries

Meniscal injuries are increasing dramatically with the aging of the population and the prevalence of sports. Tissue engineering technology is the most promising method for the treatment of meniscal injuries, but the preparation of long-term and durable meniscal scaffolds with mechanical and tribological properties like natural articular cartilage remains a great challenge. Here, inspired by the structure and lubrication mechanism of the meniscus, a durable meniscus scaffold with bionic 3D structure, self-lubrication, and intelligent drug release function is prepared. An elastomer-hydrogel composite consisting of a direct ink writing (DIW) printed elastomer skeleton and a hydrogel matrix is prepared for the meniscus scaffold. The bionic 3D structure of the scaffolds is realized by combining computer-aided structural design and 3D printing technology. The self-healing ability obtained by incorporating dynamic covalent bonds, and the robust interface achieved by co-curing of the elastomer and hydrogel resins, ensure the stability and durability of the composite meniscal scaffolds. Taking advantage of the coexistence of aqueous and oily phases in the emulsion-type hydrogel resin, a hydrophobic phospholipid is loaded into the hydrogel, and achieves excellent boundary lubrication of the composite through its fiction-response release and self-assembly. Moreover, the meniscus scaffolds enable intelligent drug release to adapt to the physiological characteristics during inflammation. In vivo tests in rabbit models validate the protective effect of the scaffold on cartilage. These methods and concepts provide a solid foundation for the preparation of bionic tissue scaffolds.

Cutting-Edge Hydrogel Technologies in Tissue Engineering and Biosensing: An Updated Review.

Hydrogels, known for their unique ability to retain large amounts of water, have emerged as pivotal materials in both tissue engineering and biosensing applications. This review provides an updated and comprehensive examination of cutting-edge hydrogel technologies and their multifaceted roles in these fields. Initially, the chemical composition and intrinsic properties of both natural and synthetic hydrogels are discussed, highlighting their biocompatibility and biodegradability. The manuscript then probes into innovative scaffold designs and fabrication techniques such as 3D printing, electrospinning, and self-assembly methods, emphasizing their applications in regenerating bone, cartilage, skin, and neural tissues. In the realm of biosensing, hydrogels' responsive nature is explored through their integration into optical, electrochemical, and piezoelectric sensors. These sensors are instrumental in medical diagnostics for glucose monitoring, pathogen detection, and biomarker identification, as well as in environmental and industrial applications like pollution and food quality monitoring. Furthermore, the review explores cross-disciplinary innovations, including the use of hydrogels in wearable devices, and hybrid systems, and their potential in personalized medicine. By addressing current challenges and future directions, this review aims to underscore the transformative impact of hydrogel technologies in advancing healthcare and industrial practices, thereby providing a vital resource for researchers and practitioners in the field.

Injectable dual drug-loaded thermosensitive liposome-hydrogel composite scaffold for vascularised and innervated bone regeneration

Adequate blood supply and thorough innervation are essential to the survival of tissue-engineered bones. Though great progress has been created in the application of bone tissue engineering technology to bone defect repair, many challenges remain, such as insufficient vascularisation and deficient innervation in newly regenerated bone. In the present study, we addressed these challenges by manipulating the bone regeneration microenvironment in terms of vascularisation and innervation. We used a novel injectable thermosensitive liposome-hydrogel composite scaffold as a sustained-release carrier for basic fibroblast growth factor (bFGF, which promotes angiogenesis and neurogenic differentiation) and dexamethasone (Dex, which promotes osteogenic differentiation). In vitro biological assessment demonstrated that the composite scaffold had sufficient cell compatibility; it enhanced the capacity for angiogenesis in human umbilical vein endothelial cells, and the capacity for neurogenic/osteogenic differentiation in human bone marrow mesenchymal stem cells. Moreover, the introduction of bFGF/Dex liposome-hydrogel composite scaffold to bone defect sites significantly improved vascularisation and innervated bone regeneration properties in a rabbit cranial defect model. Based on our findings, the regeneration of sufficiently vascularised and innervated bone tissue through a sustained-release scaffold with excellent injectability and body temperature sensitivity represents a promising tactic towards bone defect repair.

Interleukin-4-Loaded Gelatin Methacryloyl Hydrogel Promotes Subcutaneous Chondrogenesis of Engineered Auricular Cartilage in a Rabbit Model.

Tissue engineering technology offers a promising solution for ear reconstruction; however, it faces the challenge of foreign body reaction and neocartilage malformation. This study investigates the impact of interleukin-4 (IL-4), an anti-inflammatory factor, on cartilage regeneration of hydrogel encapsulating autologous auricular chondrocytes in a rabbit subcutaneous environment. Initially, we assessed the influence of IL-4 on chondrocyte proliferation and determined the appropriate concentration using the CCK-8 test in vitro. Subsequently, we loaded IL-4 into gelatin methacryloyl (GelMA) hydrogel containing chondrocytes and measured its release profile through ELISA. The constructs were then implanted autologously into rabbits' subcutis, and after 3, 7, 14, and 28 days, cartilage matrix formation was evaluated by histological examinations, and gene expression levels were detected by qRT-PCR. Results demonstrated that IL-4 promotes chondrocyte proliferation in vitro, and maximum release from constructs occurred during the first week. In the rabbit subcutaneous implantation model, IL-4-loaded constructs (20 ng/mL) maintained a superior chondrocytic phenotype compared to controls with increased expression of anti-inflammatory factors. These findings highlight IL-4 as a potential strategy for promoting chondrogenesis in a subcutaneous environment and improving ear reconstruction.

Algorithm of surgical treatment for diaphyseal defects of the forearm bones due to gunshot injuries

Introduction In the current system of providing medical aid to wounded servicemen, along with the conservative primary surgical treatment and minimally invasive extrafocal fixation, high-tech surgical interventions of considerable complexity with the use of additive and tissue-engineering technologies have been coming to the forefront. It is necessary to determine their place in the current algorithm of limb bone defect management, which was the substantiation of our study.The purpose of the study was to improve the algorithm for selecting a treatment method for patients with associated gunshot defects of the forearm based on the literature and clinical observations.Materials and Methods We analyzed scientific articles in PubMed and Scientific Electronic Library (eLIBRARY.ru) platforms, published from 2004 to 2024, on the basis of which we could refine the algorithm of treatment method selection for patients with associated gunshot defects of the forearm. The developed algorithm was used to treat 178 patients with gunshot fractures of the forearm.Results The review of the literature established the main provisions and principles that are applied in the reconstruction of the forearm with an associated defect. When choosing the method of bone defect management, a great number of authors tend to build a “reconstructive ladder”, moving from less severe (one bone) and extended defects (small defect up to 2 cm) to more complex (both bones) and massive defect (more than 10 cm). Upon having considered the revealed regularities, we improved the algorithm of surgical treatment of the latter, which is based on two classification principles: defect extention and location. Reconstruction of the forearm as a dynamic system after diaphyseal fractures requires consider the state of the radioulnar joint. The function of the latter depends on the length ratio of the radius and ulna bones. Therefore, we substantiated small (up to 2 cm) forearm bone defects that can be managed by simple surgical methods. Another fundamental addition to the algorithm was the allocation of a patients’ group with a defect of one forearm bone and a fracture of the other bone (defect-fracture); this combination allows avoiding complex surgical methods for reconstruction and use segment shortening.Discussion The treatment of associated forearm defects is challenging, the choice of reconstruction technique remains uncertain, and the required consensus is lacking. Several forearm reconstruction techniques are available, yet there is no reliable evidence of their effectiveness in terms of treatment time, complications, reoperations, and functional recovery.Conclusion The algorithm proposed for the treatment of extensive gunshot-associated defects of the forearm allows us to consider the change in the anatomy, make a surgical plan based on the reconstruction vector, and select optimal surgical techniques.

Recent advances in shape memory scaffolds and regenerative outcomes.

The advent of tissue engineering (TE) technologies has revolutionized human medicine over the last few decades. Despite splendid advances in the fabricating and development of different substrates for regenerative purposes, non-responsive static composites have been used to heal injured tissues. After being transplanted into the target sites, grafts will lose their original features, leading to a reduction in regenerative potential. Along with these statements, the use of shape memory polymers (SMPs), smart substrates with unique physicochemical properties, has been extended in different disciplines of regenerative medicine in recent years. These substrates are intelligent and they can easily change physicogeometry features such as stiffness, strain size, shape, etc. in response to external stimuli. It has been proposed that SMPs can easily acquire their original properties after deformation, even in the presence or absence of certain stimuli. It has been indicated that the application of distinct synthesis protocols is required to fabricate dynamically switchable surfaces with prominent cell-to-substrate interaction, resulting in better regulation of cell function, dynamic growth, and reparative mechanisms. Here, we aimed to scrutinize the prominent regenerative properties of SMPs in the TE and regenerative medicine fields. Whether and how SMPs can orchestrate certain cell behavior, with reconfigurable features and adaptability were discussed in detail.

Efficient fabrication of 3D bioprinted functional sensory neurons using an inducible Neurogenin-2 human pluripotent stem cell line

Three-dimensional (3D) tissue models have gained recognition for their improved ability to mimic the native cell microenvironment compared to traditional two-dimensional models. This progress has been driven by advances in tissue-engineering technologies such as 3D bioprinting, a promising method for fabricating biomimetic living tissues. While bioprinting has succeeded in generating various tissues to date, creating neural tissue models remains challenging. In this context, we present an accelerated approach to fabricate 3D sensory neuron (SN) structures using a transgenic human pluripotent stem cell (hPSC)-line that contains an inducible Neurogenin-2 (NGN2) expression cassette. The NGN2 hPSC line was first differentiated to neural crest cell (NCC) progenitors, then incorporated into a cytocompatible gelatin methacryloyl-based bioink for 3D bioprinting. Upregulated NGN2 expression in the bioprinted NCCs resulted in induced SN (iSN) populations that exhibited specific cell markers, with 3D analysis revealing widespread neurite outgrowth through the scaffold volume. Calcium imaging demonstrated functional activity of iSNs, including membrane excitability properties and voltage-gated sodium channel (NaV) activity. This efficient approach to generate 3D bioprinted iSN structures streamlines the development of neural tissue models, useful for the study of neurodevelopment and disease states and offering translational potential.

Bi-layered Adipose Mesenchymal Cell Sheets Improve Bladder Compliance in Spinal Cord-Injured Rats.

To improve bladder compliance in patients with low-compliance bladders, augmentation cystoplasty with the intestinal tract is performed. However, the use of the intestinal tract often leads to serious surgical complications. Tissue engineering technologies have the potential to improve bladder compliance without using the intestinal tract. In this study, we fabricated bi-layered adipose-derived mesenchymal cell (AMC) sheets and then determined whether the bi-layered AMC sheets could improve bladder compliance in rats with spinal cord injury (SCI). The abdominal adipose tissues of green fluorescence protein (GFP)-transfected Sprague-Dawley (SD) rats were harvested, and the attached and proliferating cells on type I collagen were used as AMCs. The AMCs were then cultured on temperature-responsive culture dishes. After reaching over-confluence, the AMCs that maintained cell-cell contacts were detached from the dishes and applied to a gelatin hydrogel sheet. Then, another detached AMC monolayer was accumulated on the AMC monolayer-applied gelatin. Prior to 4 weeks of transplantation, the levels of T8-9 in the spinal cords of recipient SD rats were partially transected. After producing the bi-layered AMC sheets and the rats with SCI, the detrusor muscles of the anterior bladder walls of the rats with SCI were incised, and the bi-layered AMC sheet was patch-transplanted onto the exposed bladder epithelium (n = 8). As a control, the sham operation was performed (n = 7). Four weeks after the transplantation, bladder capacity and bladder compliance in AMC sheet-transplanted SCI rats were significantly higher than those in sham-operated control SCI rats. The smooth muscle layers in AMC sheet-transplanted bladders were significantly larger than those in control bladders. In addition, the collagen fibers in the AMC sheet-transplanted bladders were significantly smaller than those in the control bladders. Some GFP-positive transplanted AMCs differentiated into smooth muscle actin- or desmin-positive cells. Furthermore, GFP-positive cells secreted transforming growth factor-β1 or vascular endothelial growth factor. Therefore, this study showed that bi-layered AMC sheets could improve bladder compliance and bladder tissues in SCI rats.

3D printing of hydrogel composite systems: Recent advances in technology for tissue engineering.

Three-dimensional (3D) printing of hydrogels is now an attractive area of research due to its capability to fabricate intricate, complex and highly customizable scaffold structures that can support cell adhesion and promote cell infiltration for tissue engineering. However, pure hydrogels alone lack the necessary mechanical stability and are too easily degraded to be used as printing ink. To overcome this problem, significant progress has been made in the 3D printing of hydrogel composites with improved mechanical performance and biofunctionality. Herein, we provide a brief overview of existing hydrogel composite 3D printing techniques including laser based-3D printing, nozzle based-3D printing, and inkjet printer based-3D printing systems. Based on the type of additives, we will discuss four main hydrogel composite systems in this review: polymer- or hydrogel-hydrogel composites, particle-reinforced hydrogel composites, fiber-reinforced hydrogel composites, and anisotropic filler-reinforced hydrogel composites. Additionally, several emerging potential applications of hydrogel composites in the field of tissue engineering and their accompanying challenges are discussed in parallel.

3D-printed gradient scaffolds for osteochondral defects: Current status and perspectives.

Articular osteochondral defects are quite common in clinical practice, and tissue engineering techniques can offer a promising therapeutic option to address this issue.The articular osteochondral unit comprises hyaline cartilage, calcified cartilage zone (CCZ), and subchondral bone.As the interface layer of articular cartilage and bone, the CCZ plays an essentialpart in stress transmission and microenvironmental regulation.Osteochondral scaffolds with the interface structure for defect repair are the future direction of tissue engineering. Three-dimensional (3D) printing has the advantages of speed, precision, and personalized customization, which can satisfy the requirements of irregular geometry, differentiated composition, and multilayered structure of articular osteochondral scaffolds with boundary layer structure. This paper summarizes the anatomy, physiology, pathology, and restoration mechanisms of the articular osteochondral unit, and reviews the necessity for a boundary layer structure in osteochondral tissue engineering scaffolds and the strategy for constructing the scaffolds using 3D printing. In the future, we should not only strengthen the basic research on osteochondral structural units, but also actively explore the application of 3D printing technology in osteochondral tissue engineering. This will enable better functional and structural bionics of the scaffold, which ultimately improve the repair of osteochondral defects caused by various diseases.

Strategies To Enhance Biocompatibility of Bone Scaffold for Tissue Engineering Applications

Tissue engineering (TE) is a modern approach to improve or restore tissues that has been diseased or damaged by combining the factors in growth signaling and appropriate cells to form compatible biomaterial scaffold. Bone repair has been a major global health challenge in recent decades. Bone transplantation is widely used as an effective clinical treatment for this purpose. However, there are several serious issues with transplantation, including a shortage of autologous bone, immune rejection, the risk of virus transmission with allogeneic bone, and postoperative complications. In recent years, scaffolds for bone tissue engineering have emerged as a promising alternative for bone repair. These scaffolds have porous structures that mimic the extracellular matrix, which can enhance the migration, proliferation, and differentiation of osteoblasts. This process accelerates the repair of bone defects.The usage of bioactive materials has become important tool in tissue engineering and regenerative medicine application as they are to mimic tissues mechanically, chemically, and physically. Polymeric scaffold provides numerous advantageous for tissue engineering since the physicochemical properties such as porosity, pore size, solubility and biocompatibility can be controlled. Therefore, research works were carried out to explore the potential of various materials in producing bone scaffolds in tissue engineering technology. As for both newcomers and experts, this review paper will help them to find information on various types of biomaterials in imparting or enhancing their biological properties such as biocompatibility, bacterial inhibition, tissue regeneration and cell growth, bio inertness, bioactive and resorbability for bone scaffold tissue engineering application.

3D Porous Polymer Scaffold-Conjugated KGF-Mimetic Peptide Promotes Functional Skin Regeneration in Chronic Diabetic Wounds.

The re-epithelialization process gets severely dysregulated in chronic nonhealing diabetic foot ulcers/wounds. Keratinocyte growth factor (KGF or FGF-7) is the major modulator of the re-epithelialization process, which regulates the physiological phenotypes of cutaneous keratinocytes. The existing therapeutic strategies of growth factor administration have several limitations. To overcome these, we have designed a KGF-mimetic peptide (KGFp, 13mer) based on the receptor interaction sites in murine KGF. KGFp enhanced migration and transdifferentiation of mouse bone marrow-derived MSCs toward keratinocyte-like cells (KLCs). A significant increase in the expression of skin-specific markers Bnc1 (28.5-fold), Ck5 (14.6-fold), Ck14 (26.1-fold), Ck10 (187.7-fold), and epithelial markers EpCam (23.3-fold) and Cdh1 (64.2-fold) was associated with the activation of ERK1/2 and STAT3 molecular signaling in the KLCs. Further, to enhance the stability of KGFp in the wound microenvironment, it was conjugated to biocompatible 3D porous polymer scaffolds without compromising its active binding sites followed by chemical characterization using Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic mechanical analysis, and thermogravimetry. In vitro evaluation of the KGFp-conjugated 3D polymer scaffolds revealed its potential for transdifferentiation of MSCs into KLCs. Transplantation of allogeneic MSCGFP using KGFp-conjugated 3D polymer scaffolds in chronic nonhealing type 2 diabetic wounds (db/db transgenic, 50-52 weeks old male mice) significantly enhanced re-epithelialization-mediated wound closure rate (79.3%) as compared to the control groups (Untransplanted -22.4%, MSCGFP-3D polymer scaffold -38.5%). Thus, KGFp-conjugated 3D porous polymer scaffolds drive the fate of the MSCs toward keratinocytes that may serve as potential stem cell delivery platform technology for tissue engineering and transplantation.

Construction, Features and Regulatory Aspects of Organ-chip for Drug Delivery Applications: Advances and Prospective

: Organ-on-chip is an innovative technique that emerged from tissue engineering and microfluidic technologies. Organ-on-chip devices (OoCs) are anticipated to provide efficient explanations for dealing with challenges in pharmaceutical advancement and individualized illness therapies. Organ-on-chip is an advanced method that can replicate human organs' physiological conditions and functions on a small chip. It possesses the capacity to greatly transform the drug development process by enabling the simulation of diseases and the testing of drugs. Effective integration of this advanced technical platform with common pharmaceutical and medical contexts is still a challenge. Microfluidic technology, a micro-level technique, has become a potent tool for biomedical engineering research. As a result, it has revolutionized disciplines, including physiological material interpreting, compound detection, cell-based assay, tissue engineering, biological diagnostics, and pharmaceutical identification. This article aims to offer an overview of newly developed organ-on-a-chip systems. It includes single-organ platforms, emphasizing the most researched organs, including the heart, liver, blood arteries, and lungs. Subsequently, it provides a concise overview of tumor-on-a-chip systems and emphasizes their use in evaluating anti-cancer medications.

Application of right ventricular to pulmonary valved conduit in the surgical treatment of congenital heart disease.

Pulmonary valve replacement and right ventricular outflow tract reconstruction with valved conduits have been the shortcomings of paediatric cardiac surgeons in the treatment of CHD. In recent decades, encouraging achievements have been made in right ventricular outflow tract technology. Since Klinner reported the first right ventricle-to-pulmonary artery connection using unvalved conduits made of autologous pericardium in 1964, various right ventricle-to-pulmonary artery conduits have gradually been used in the treatment of various complex CHD. Compared with other materials, valved homograft conduit (VHC) is more consistent with physiological characteristics, better haemodynamics, easy suture and good haemostasis, anti-calcification, anti-infection, and without the need for lifelong anticoagulation, which makes VHC the best material for reconstruction of right ventricular outflow tract. However, due to the shortage of donor sources, other alternative conduits such as polytetrafuoroethylene valved conduits have been developed, and the results are not inferior to VHC in clinical application. The emerging tissue engineering technology is expected to utilise recipient-derived endothelial cells for implantation onto the decellularized VHC or degradable synthetic materials in order to construct a recipient-specific tissue-engineered valved conduit. This advancement holds great potential as an ideal biological transplant material and valve replacement for CHD. It will completely solve the problems of immune rejection and the growth of the conduit that cannot adapt to the physical growth of children. This review provides a comprehensive review of the clinical indications for right ventricle-to-pulmonary artery conduits application, optimal timing for surgery, current practices in utilising various types of external conduits, and considerations for re-replacement.

From Promise to Practice: Recent Growth in 30 Years of Tissue Engineering Commercialization.

This perspective, marking the 30th anniversary of the Tissue Engineering journal, discusses the exciting trends in the global commercialization of tissue engineering technology. Within a historical context, we present an evolution of challenges and a discussion of the last 5 years of global commercial successes and emerging market trends, highlighting the continued expansion of the field in the northeastern United States. This leads to an overview of the last 5 years' progress in clinical trials for tissue engineered therapeutics, including an analysis of trends in success and failure. Finally, we provide a broad overview of preclinical research and a perspective on where the state-of-the-art lies on the horizon.