Biological Scaffolds Research Articles

Use of a biological scaffold in the cleavage area in complex revision breast augmentation: A surgical technique and case series

BackgroundBilateral breast augmentation has been the top surgical procedure performed worldwide by plastic surgeons for the past 5 years. Complex breast revision patients are challenging, with the cleavage area being one of the most difficult areas to navigate. We present a novel technique for using biological scaffolds in revision breast augmentation surgery. MethodsA step-by-step surgical technique is presented, combined with a series of 11 cases where either SurgiMend® acellular dermal matrix (ADM) or GalaFLEX mesh was used specifically in the medial cleavage area to correct a difficult to manage soft tissue contour deformity. ResultsEleven patients underwent revision breast augmentation with the use of the biological scaffolds in the medial cleavage area. The mean age was 43 years with a range of 29–68 years. All replacement breast implants were anatomical-shaped, medium profile, polyurethane-coated implants. GalaFLEX® mesh was used in six patients; five patients received SurgiMend® ADM. Mastopexy was performed in 8/11 patients. There were two complications in the same patient in this series, one emergency return to theater for bleeding and one minor scar revision. ConclusionsRevision breast augmentation surgery includes a smorgasbord of options that can be used individually or in combination, such as full or partial capsulectomy, removal alone or replacement of the implant, change to the tissue plane of where the implant sits, mastopexy, and fat transfer. In addition to these recognized treatments, we would like to advocate the option of a biological scaffold for extra support of the cleavage area in complex revision cases.

Applications of antioxidant nanoparticles and hydrogels in osteoarthritis: A review

During osteoarthritis, the oxidation-reduction balance will be broken, resulting in the excessive formation of reactive oxygen species. These reactive oxygen species have been shown to disrupt proteins, lipids, and deoxyribonucleic acid. They induce oxidative strain, which can induce the development of osteoarthritis and lead to worse consequences. To solve this problem, antioxidant molecules have attracted wide attention for their ability to scavenge free radicals and reactive oxygen species. Nevertheless, most antioxidants encounter obstacles that affect their bioavailability, including a narrow absorption capacity, difficulty in penetrating cell membranes, and disintegration during delivery. Therefore, to solve these problems, the excellently targeted delivery, biocompatibility, deformability, and other characteristics of nanoparticles and hydrogels have been considered, and nanoparticles and hydrogels are at present being widely developed as antioxidant carriers. Nanoparticles and hydrogels that target the oxidative stress pathway can be mixed with antioxidants to increase their bioavailability, adhesion, and other related characteristics, which leads to better treatment of osteoarthritis. This research study aims to examine the biological scaffolds of osteoarthritis, which contain antioxidant nanoparticles and antioxidant hydrogels, as well as process controlling reactive oxygen compounds throughout the entire knee joint cavity. In addition, current challenges and potential solutions that can use antioxidant nanoparticles and antioxidant hydrogel biological scaffolds have been proposed to provide a theoretical basis for their future clinical applications.

Preliminary study on a novel biological scaffold loaded with Apelin-13 sustained-release microcapsules for promoting fallopian tube recanalization in rabbits.

Tubal factor infertility severely impairs the natural fertility of women, and there is for genuine tubal recanalization, including restoration of both the anatomy and function of the diseased fallopian tubes. Currently, there is no effective treatment available. This study aims to explore methods for promoting the repair and recanalization of fallopian tubes from these 2 aspects. Apelin-13 sustained-release microspheres and poly (lactic-co-glycolic acid) (PLGA) three-dimensional (3D) biodegradable scaffolds were prepared. The basic characteristics and in vivo degradation (mass loss rate) of the biodegradable scaffolds were tested, along with the in vitro drug release (cumulative release rate), the in vivo drug release (Apelin-13 plasma concentration), and in vitro degradation (degradation rate) of the microspheres. The Apelin-13 microspheres (microsphere group)/PLGA 3D scaffolds loaded with Apelin-13 sustained-release microspheres (scaffold-microcapsule group) were injected/placed into the fallopian tubes of New Zealand rabbit of chronic salpingitis models. The patency, microscopic structure, and positive expression of estrogen receptor and progesterone receptor of the fallopian tubes in the control group, the model group, the microcapsule group, and the scaffold-microcapsule group was observed and compared. At the 4th week post-operation, the mass loss rate of the PLGA 3D scaffolds, the degradation rate of the microspheres, and the Apelin-13 sustained-release microspheres-generated cumulative release rate in vitro over 30 days were 98.66%, 70.58%, and 98.68% respectively. The plasma concentration of Apelin-13 reached its peak within 5 days and remained stable for 25 days. Compared with the model and microsphere groups, the scaffold-microsphere group showed a milder inflammatory reaction within the tubal lumen, a higher rate of fallopian tube patency, and higher expression levels of estrogen and progesterone receptors (all P<0.05). The indicators of the scaffold-microsphere group were close to those of the control group. The PLGA 3D scaffolds loaded with Apelin-13 sustained-release microspheres can comprehensively repair the anatomical structure and physiological function of the fallopian tubes and hold promise for truly effective tubal recanalization.

Engineered neural tissue made using hydrogels derived from decellularised tissues for the regeneration of peripheral nerves.

Engineered neural tissue (EngNT) promotes in vivo axonal regeneration. Decellularised materials (dECM) are complex biologic scaffolds that can improve the cellular environment and also encourage positive tissue remodelling in vivo. We hypothesised that we could incorporate a hydrogel derived from a decellularised tissue (dECMh) into EngNT, thereby providing an alternative to the currently used purified collagen I hydrogel for the first time. Decellularisation was carried out on bone (B-ECM), liver (LIV-ECM), and small intestinal (SIS-ECM) tissues and the resultant dECM was biochemically and mechanically characterised. dECMh differed in mechanical and biochemical properties that likely had an effect on Schwann cell behaviour observed in metabolic activity and contraction profiles. Cellular alignment was observed in tethered moulds within the B-ECM and SIS-ECM derived hydrogels only. No difference was observed in dorsal root ganglia (DRG) neurite extension between the dECMh groups and collagen I groups when applied as a coverslip coating, however, when DRG were seeded atop EngNT constructs, only the B-ECM derived EngNT performed similarly to collagen I derived EngNT. B-ECM EngNT further exhibited similar axonal regeneration to collagen I EngNT in a 10 mm gap rat sciatic nerve injury model after 4 weeks. Our results have shown that various dECMh can be utilised to produce EngNT that can promote neurite extension in vitro and axonal regeneration in vivo. STATEMENT OF SIGNIFICANCE: Nerve autografts are undesirable due to the sacrifice of a patient's own nerve tissue to repair injuries. Engineered neural tissue (EngNT) is a type of living artificial tissue that has been developed to overcome this. To date, only a collagen hydrogel has been shown to be effective in the production and utilisation of EngNT in animal models. Hydrogels may be made from decellularised extracellular matrix derived from many tissues. In this study we showed that hydrogels from various tissues may be used to create EngNT and one was shown to comparable to the currently used collagen based EngNT in a rat sciatic nerve injry model.

3D Printing and Performance Study of Porous Artificial Bone Based on HA-ZrO2-PVA Composites.

An ideal artificial bone implant should have similar mechanical properties and biocompatibility to natural bone, as well as an internal structure that facilitates stomatal penetration. In this work, 3D printing was used to fabricate and investigate artificial bone composites based on HA-ZrO2-PVA. The composites were proportionally configured using zirconia (ZrO2), hydroxyapatite (HA) and polyvinyl alcohol (PVA), where the ZrO2 played a toughening role and PVA solution served as a binder. In order to obtain the optimal 3D printing process parameters for the composites, a theoretical model of the extrusion process of the composites was first established, followed by the optimization of various parameters including the spray head internal diameter, extrusion pressure, extrusion speed, and extrusion line width. The results showed that, at the optimum parameters of a spray head diameter of 0.2 mm, extrusion pressure values ranging from 1-3 bar, a line spacing of 0.8-1.5 mm, and a spray head displacement range of 8-10 mm/s, a better structure of biological bone scaffolds could be obtained. The mechanical tests performed on the scaffolds showed that the elastic modulus of the artificial bone scaffolds reached about 174 MPa, which fulfilled the biomechanical requirements of human bone. According to scanning electron microscope observation of the scaffold sample, the porosity of the scaffold sample was close to 65%, which can well promote the growth of chondrocytes and angiogenesis. In addition, c5.18 chondrocytes were used to verify the biocompatibility of the composite materials, and the cell proliferation was increased by 100% when compared with that of the control group. The results showed that the composite has good biocompatibility.

A scoping review of the additive manufacturing of mandibular implants

Bone disease and fractures are among the health issues that are becoming more prevalent year after year. A mandibular disorder is caused by an accident or disease to the largest and strongest bone in the human face. Because the natural healing process of mandibular bones takes a long time, a bone grafting procedure is used to speed up the patient’s recovery. Due to the limitations of bone grafting processes such as autographs, allographs, and xenografts, bone replacement is being developed using biomaterials via 3D printing. The purpose of the review was to evaluate research on the use of 3D printing in the replacement of mandible bones. The search algorithm found as many as 2,941 articles at the start of the search and 123 articles after initial selection. Up to February 2022, the Scopus electronic database was used to conduct the literature search. This research includes publications that employ 3D printers, additive manufacturing, or finite element analysis to build or analyze mandibular implants. Paper topics in engineering, materials science, biochemistry, genetics, molecular biology, medicine, dentistry, chemical engineering, and computer science are included in this study. Papers in physics, astronomy, and energy, book chapter document types, papers reviews, and documents in languages other than English were excluded from this study. After an initial screening that included the year, publication stage, source type, and language, as many as 70 articles were obtained, and after filtering titles and abstracts obtained 55 articles. After the full-text selection was obtained, 32 articles were included in this review. Some articles were unacceptable because the topics discussed were unrelated to mandibular bone scaffolds. As a result, the field of additive manufacturing for the repair and reconstruction of mandibular defects necessitates the development of novel tools and methodologies. A customized biological scaffold can be created using an appropriate 3D printing process based on the characteristics of various mandibular defects, allowing it to be perfectly matched to the defect region and reducing stress, thereby improving the scaffold’s healing function.

Fabrication and investigation of physicochemical and biological properties of3Dprinted sodium alginate‐chitosan blend polyelectrolyte complex scaffold for bone tissue engineering application

AbstractIn tissue engineering technique, a biological scaffold with appropriate composition and structure for promoting growth and differentiation of cells thereby regenerating damaged tissue, is a prime necessity. In this paper, 3D‐printed scaffolds comprising sodium alginate (SA) and chitosan (CH) biopolymers of natural origin are reported. Bioinks with varying ratios of SA and CH were prepared and scaffolds were fabricated by 3D printing. The fabricated scaffolds possess many desired properties that are vital for tissue regeneration purposes. The scaffolds possess open pore microstructures with interconnected pores and desired pore size as revealed by scanning electron microscopic image analysis. The polyelectrolyte complex formation (PEC) between SA and CH as revealed by Fourier‐transform‐infrared spectroscopic analysis is favorable as it offers a better surface for cell attachment and proliferation, and an ideal microenvironment for bone regeneration. Among the scaffolds, SA/CH with 60:40 showed controlled swelling and degradation behavior, with higher tensile strength of 0.387 ± 0.015 MPa. In vitro‐biomineralization showed superior apatite layer deposition ability over the SA/CH: 60/40 scaffold surface. The fabricated SA/CH scaffolds are hydrophilic and biocompatible as evident from the contact angle, protein adsorption, MTT assay, and cell attachment studies. However, SA/CH: 60/40 is shown to have superior biological properties compared with the other SA/CH compositions. Thus, it is concluded that 3Dv printed SA/CH: 60/40 scaffold having some superior properties and bioactivity can be used as a suitable matrix for future bone tissue regeneration applications.

Biological Scaffolds for Congenital Heart Disease.

Congenital heart disease (CHD) is the most predominant birth defect and can require several invasive surgeries throughout childhood. The absence of materials with growth and remodelling potential is a limitation of currently used prosthetics in cardiovascular surgery, as well as their susceptibility to calcification. The field of tissue engineering has emerged as a regenerative medicine approach aiming to develop durable scaffolds possessing the ability to grow and remodel upon implantation into the defective hearts of babies and children with CHD. Though tissue engineering has produced several synthetic scaffolds, most of them failed to be successfully translated in this life-endangering clinical scenario, and currently, biological scaffolds are the most extensively used. This review aims to thoroughly summarise the existing biological scaffolds for the treatment of paediatric CHD, categorised as homografts and xenografts, and present the preclinical and clinical studies. Fixation as well as techniques of decellularisation will be reported, highlighting the importance of these approaches for the successful implantation of biological scaffolds that avoid prosthetic rejection. Additionally, cardiac scaffolds for paediatric CHD can be implanted as acellular prostheses, or recellularised before implantation, and cellularisation techniques will be extensively discussed.

Silk Fibroin Hybrids for Biological Scaffolds with Adhesive Surface and Adaptability to the Target Tissue Change

Abstract Background Regenerative Medicine (RM) is a branch of medicine that aims to regenerate tissues and organs to overcome the problems transplants entail (poor availability, risk of rejection and intense immunosuppression). To do this, RM makes use of tissue engineering (TE). This fundamental branch deals with creating biological scaffolds capable of performing the role that physiologically belongs to the extracellular matrix (ECM). In this review, we report how specific characteristics of the scaffolds (bio-compatibility, biodegradability and mechanical and conformal properties) can be obtained using 3D printing, which facilitates the emulation of physiological tissues and organs. Purpose and scope This review reports recent advances in the fabrication method of bioactive scaffolds that can be used clinically, providing support for cell seeding and proliferation. To this end, silk fibroin, tannin and graphene were used to improve the scaffold’s electro-bio-mechanical properties. These materials in different compositions are studied to demonstrate their potential use as bio-ink in bioadhesives and cellularized and implantable 3D-printed scaffolds. Summary of new synthesis and conclusions reached in the review Silk fibroin is a natural biopolymer; tannin, on the other hand, is a biological polyphenol, highly reactive with other molecules by nature and with promising antioxidant capabilities. Finally, graphene is nothing more than a monolayer of graphite that has been shown to implement the mechanics and electrical conductivity of the compounds in which it is inserted; it also has excellent biocompatibility and surface area, qualities that promote cell adhesion and growth. Conclusion Polyphenols and graphene have been shown to work in synergy in improving the electro-mechanical properties of silk fibroin scaffolds. We reported optimal and potentially market-competitive bioadhesives, but above all, the proliferation of neuronal precursor cells in vitro was successfully demonstrated.

The Dual Effect of 3D-Printed Biological Scaffolds Composed of Diverse Biomaterials in the Treatment of Bone Tumors.

Bone tumors, including primary bone tumors, invasive bone tumors, metastatic bone tumors, and others, are one of the most clinical difficulties in orthopedics. Once these tumors have grown and developed in the bone system, they will interact with osteocytes and other environmental cells in the bone system's microenvironment, leading to the eventual damage of the bone's physical structure. Surgical procedures for bone tumors may result in permanent defects. The dual-efficacy of tissue regeneration and tumor treatment has made biomaterial scaffolds frequently used in treating bone tumors. 3D printing technology, also known as additive manufacturing or rapid printing prototype, is the transformation of 3D computer models into physical models through deposition, curing, and material fusion of successive layers. Adjustable shape, porosity/pore size, and other mechanical properties are an advantage of 3D-printed objects, unlike natural and synthetic material with fixed qualities. Researchers have demonstrated the significant role of diverse 3D-printed biological scaffolds in the treatment for bone tumors and the regeneration of bone tissue, and that they enhanced various performance of the products. Based on the characteristics of bone tumors, this review synthesized the findings of current researchers on the application of various 3D-printed biological scaffolds including bioceramic scaffold, metal alloy scaffold and nano-scaffold, in bone tumors and discussed the advantages, disadvantages, and future application prospects of various types of 3D-printed biological scaffolds. Finally, the future development trend of 3D-printed biological scaffolds in bone tumor is summarized, providing a theoretical foundation and a larger outlook for the use of biological scaffolds in the treatment of patients with bone tumors.

Living Chinese Herbal Scaffolds from Microfluidic Bioprinting for Wound Healing.

Biological scaffolds have been widely employed in wound healing applications, while their practical efficiency is compromised by insufficient oxygen delivery to the 3-dimensional constructs and inadequate nutrient supply for the long-term healing process. Here, we present an innovative living Chinese herbal scaffold to provide a sustainable oxygen and nutrient supply for promoting wound healing. Through a facile microfluidic bioprinting strategy, a traditional Chinese herbal medicine (Panax notoginseng saponins [PNS]) and a living autotrophic microorganism (microalgae Chlorella pyrenoidosa [MA]) were successfully encapsulated into the scaffolds. The encapsulated PNS could be gradually released from the scaffolds, which promoted cell adhesion, proliferation, migration, and tube formation invitro. In addition, benefiting from the photosynthetic oxygenation of the alive MA, the obtained scaffolds would produce sustainable oxygen under light illumination, exerting a protective effect against hypoxia-induced cell death. Based on these features, we have demonstrated through invivo experiments that these living Chinese herbal scaffolds could efficiently alleviate local hypoxia, enhance angiogenesis, and thereby accelerate wound closure in diabetic mice, indicating their great potential in wound healing and other tissue repair applications.

Forming Model Optimization and Microstructural Analysis of Medical Biological Porous Scaffolds Fabricated by Selective Laser Melting (SLM)

Forming Model Optimization and Microstructural Analysis of Medical Biological Porous Scaffolds Fabricated by Selective Laser Melting (SLM)

Collagen biomaterials promote the regenerative repair of abdominal wall defects in Bama miniature pigs.

Due to adhesion and rejection of recent traditional materials, it is still challenging to promote the regenerative repair of abdominal wall defects caused by different hernias or severe trauma. However, biomaterials with a high biocompatibility and low immunogenicity have exhibited great potential in the regeneration of abdominal muscle tissue. Previously, we have designed a biological collagen scaffold material combined with growth factor, which enables a fusion protein-collagen binding domain (CBD)-basic fibroblast growth factor (bFGF) to bind and release specifically. Though experiments in rodent animals have indicated the regeneration function of CBD-bFGF modified biological collagen scaffolds, its translational properties in large animals or humans are still in need of solid evidence. In this study, the abdominal wall defect model of Bama miniature pigs was established by artificial operations, and the defective abdominal wall was sealed with or without a polypropylene patch, and unmodified and CBD-bFGF modified biological collagen scaffolds. Results showed that a recurrent abdominal hernia was observed in the defect control group (without the use of mesh). Although the polypropylene patch can repair the abdominal wall defect, it also induced serious adhesion and inflammation. Meanwhile, both kinds of collagen biomaterials exhibited positive effects in repairing abdominal wall defects and reducing regional adhesion and inflammation. However, CBD-bFGF-modified collagen biomaterials failed to induce the regenerative repair reported in rat experiments. In addition, unmodified collagen biomaterials induced abdominal wall muscle regeneration rather than fibrotic repair. These results indicated that the unmodified collagen biomaterials are a better option among translational patches for the treatment of abdominal wall defects.

Decellularization techniques of human foreskin for tissue engineering application.

The rapid development of tissue engineering (TE) and regenerative medicine brings an acute need for biocompatible and bioactive biological scaffolds to regenerate or restore damaged tissue. Great attention is focused on the decellularization of tissues or even whole organs, and the subsequent colonization of such decellularized extracellular matrices by recipient cells. The foreskin is an integral, normal part of the external genitalia that forms the anatomical covering of the glans penis and the urinary meatus of all human and non-human primates. It is mucocutaneous tissue that marks the boundary between mucosa and skin. In this work, we compared two innovative decellularization techniques for human foreskins obtained from donors. We compared the efficacy and feasibility of these protocols and the biosafety of prepared acellular dermal matrixes that can serve as a suitable scaffold for TE. The present study confirms the feasibility of foreskin decellularization based on enzymatic or detergent methods. Both techniques conserved the ultrastructure and composition of natural ECM while being DNA-free and non-toxic, making it an excellent scaffold for follow-up research and TE applications.

Research Progress and Challenges of 3D Printed Conductive Biological Scaffolds

Research Progress and Challenges of 3D Printed Conductive Biological Scaffolds

A spatial statistical framework for the parametric study of fiber networks: Application to fibronectin deposition by normal and activated fibroblasts.

Due to the complex architectural diversity of biological networks, there is an increasing need to complement statistical analyses with a qualitative and local description of their spatial properties. One such network is the extracellular matrix (ECM), a biological scaffold for which changes in its spatial organization significantly impact tissue functions in health and disease. Quantifying variations in the fibrillar architecture of major ECM proteins should considerably advance our understanding of the link between tissue structure and function. Inspired by the analysis of functional magnetic resonance imaging (fMRI) images, we propose a novel statistical analysis approach embedded into a machine learning paradigm, to measure and detect local variations of meaningful ECM parameters. We show that parametric maps representing fiber length and pore directionality can be analyzed within the proposed framework to differentiate among various tissue states. The parametric maps are derived from graph-based representations that reflect the network architecture of fibronectin (FN) fibers in a normal, or disease-mimicking in vitro setting. Such tools can potentially lead to a better characterization of dynamic matrix networks within fibrotic tumor microenvironments and contribute to the development of better imaging modalities for monitoring their remodeling and normalization following therapeutic intervention.

A Systematic Review of Tissue Engineering of a Total Artificial Heart: Focus on Perfusion Decellularization

Introduction: A leading cause of death worldwide is heart disease, and in the United States alone, 6.2 million individuals live with heart failure. The recent ability to recreate the vascular network of cardiac Extracellular Matrix (ECM) suggests the feasibility of engineering whole heart constructs. Tissue engineering method such as perfusion decellularization allows for effective removal of nearly all cellular composition of a heart while maintaining the native mechanical integrity of the scaffold. This scaffold can be reseeded with stem cells in the hopes of generating a functional heart. The goal of this systematic review was to assess the various perfusion decellularization methods and its effects upon the biologic scaffold. Methodology: A comprehensive systematic literature review search was carried out through Pubmed, MEDLINE and Google Scholar using the search terms “whole heart decellularization”, “whole organ decellularization” and “perfusion decellularization”. The inclusion criteria for this research were as follows: scholarly or peer-reviewed studies, published within the last 20 years in the English language, and primary studies in which whole cardiac organ decellularization was performed. Chosen articles were those examining the various decellularization methods and its effects upon the biologic scaffold. Excluded were studies regarding heart valve decellularization, tissue decellularization, cardiac patch, tissue recellularization, articles in foreign languages, articles dated prior to 2001, literature reviews, systematic reviews, and duplicate articles. Results: Chemical agents such as acid and bases cause hydrolytic degradation of biomolecules which could reduce ECM strength and eliminate growth factors from the matrix. Compared to other detergents such as Triton X-100, sodium dodecyl sulfate yields a more complete removal of nuclear material. A combination of these various approaches has shown an increased efficacy of the decellularization process. The decellularization of a large solid organ such as the heart requires several sophisticated steps. Perfusion decellularization is achieved via anterograde or retrograde perfusion of the intrinsic vascular network of the heart by utilizing decellularizing agents (i.e., chemicals and/or enzymes). Hodgson et al., 2017 demonstrates a combined strategy in which the decellularization of porcine hearts is accomplished in 24 hours and results in 98% DNA removal with only 6 hours of detergent exposure. Conclusion: There have been significant advances to address the heart disease epidemic. A promising approach is perfusion decellularization which allows for complete DNA content removal while maintaining the ECM scaffold integrity. This scaffold is then re-cellularized with stem cells in the hopes of creating an artificial heart. There are several challenges that need to be surpassed before bio-artificial hearts can be used to replace in vivo function. Future research is directed towards optimizing types of cells and cell sources used to repopulate decellularized hearts, seeding strategies and bioreactor systems to provide in vitro conditions required for organ maturation.

Advances in Skin Tissue Engineering and Regenerative Medicine.

There are an estimated 500,000 patients treated with full-thickness wounds in the United States every year. Fire-related burn injuries are among the most common and devastating types of wounds that require advanced clinical treatment. Autologous split-thickness skin grafting is the clinical gold standard for the treatment of large burn wounds. However, skin grafting has several limitations, particularly in large burn wounds, where there may be a limited area of non-wounded skin to use for grafting. Non-cellular dermal substitutes have been developed but have their own challenges; they are expensive to produce, may require immunosuppression depending on design and allogenic cell inclusion. There is a need for more advanced treatments for devastating burns and wounds. This manuscript provides a brief overview of some recent advances in wound care, including the use of advanced biomaterials, cell-based therapies for wound healing, biological skin substitutes, biological scaffolds, spray on skin and skin bioprinting. Finally, we provide insight into the future of wound care and technological areas that need to be addressed to support the development and incorporation of these technologies.

Achilles tendon reconstruction using a biosynthetic graft: a case report

A 56-year-old male was admitted to an outpatient clinic five months after feeling a snap in his right heel while walking in the yard. Clinical and imaging evaluation demonstrated a discontinuity of Achilles tendon (AT). The measured gap between the insertion and the proximal stump was 13cm. The patient underwent reconstruction using a bio-absorbable synthetic graft associated with a Flexor Hallucis Longus (FHL) transfer. Good functional outcomes were noted. Achilles tendon reconstruction with the biosynthetic flexible band proved feasible for massive tendon defects by inserting a biological scaffold for native tendon healing, improving postoperative recovery and strength. Level of Evidence V; Therapeutic Studies; Expert Opinion.

3D printing of injury-preconditioned secretome/collagen/heparan sulfate scaffolds for neurological recovery after traumatic brain injury in rats

BackgroundThe effects of traumatic brain injury (TBI) can include physical disability and even death. The development of effective therapies to promote neurological recovery is still a challenging problem. 3D-printed biomaterials are considered to have a promising future in TBI repair. The injury-preconditioned secretome derived from human umbilical cord blood mesenchymal stem cells showed better stability in neurological recovery after TBI. Therefore, it is reasonable to assume that a biological scaffold loaded with an injury-preconditioned secretome could facilitate neural network reconstruction after TBI.MethodsIn this study, we fabricated injury-preconditioned secretome/collagen/heparan sulfate scaffolds by 3D printing. The scaffold structure and porosity were examined by scanning electron microscopy and HE staining. The cytocompatibility of the scaffolds was characterized by MTT analysis, HE staining and electron microscopy. The modified Neurological Severity Score (mNSS), Morris water maze (MWM), and motor evoked potential (MEP) were used to examine the recovery of cognitive and locomotor function after TBI in rats. HE staining, silver staining, Nissl staining, immunofluorescence, and transmission electron microscopy were used to detect the reconstruction of neural structures and pathophysiological processes. The biocompatibility of the scaffolds in vivo was characterized by tolerance exposure and liver/kidney function assays.ResultsThe excellent mechanical and porosity characteristics of the composite scaffold allowed it to efficiently regulate the secretome release rate. MTT and cell adhesion assays demonstrated that the scaffold loaded with the injury-preconditioned secretome (3D-CH-IB-ST) had better cytocompatibility than that loaded with the normal secretome (3D-CH-ST). In the rat TBI model, cognitive and locomotor function including mNSS, MWM, and MEP clearly improved when the scaffold was transplanted into the damage site. There is a significant improvement in nerve tissue at the site of lesion. More abundant endogenous neurons with nerve fibers, synaptic structures, and myelin sheaths were observed in the 3D-CH-IB-ST group. Furthermore, the apoptotic response and neuroinflammation were significantly reduced and functional vessels were observed at the injury site. Good exposure tolerance in vivo demonstrated favorable biocompatibility of the scaffold.ConclusionsOur results demonstrated that injury-preconditioned secretome/collagen/heparan sulfate scaffolds fabricated by 3D printing promoted neurological recovery after TBI by reconstructing neural networks, suggesting that the implantation of the scaffolds could be a novel way to alleviate brain damage following TBI.Graphical abstract