Biomechanical Behaviors and Degradation Properties of Multilayered Polymer Scaffolds: The Phase Space Method for Bile Duct Design and Bioengineering

Leukopenia, weight loss and oral mucositis induced by 5-Fluorouracil in hamsters' model: A regenerative approach using electrospun poly(Lactic-co-Glycolic Acid) membrane

Clinical parameters of leukogram and weight were analyzed in animal models before and after seven days of 5-FU infusions. A comparison of leukograms before and after 5-FU administrations was analyzed. The results showed a significant difference (p = 0,004), confirming immunosuppression. There was a decrease in the weight of the animals after 7 days of 5-FU infusions (p = 0.02). After immunosuppression occurred, oral mucositis (OM) ulcerative lesions were observed. Two of the animals were selected to receive PLGA dressings. Then, electrospun PLGA membranes, with or without autologous cells, were applied to the ulcerative lesions, aiming to accelerate the regeneration process. Although this therapeutic innovation for OM lesions was still not tested in the bioengineering area, morphological analysis presented promising results. Lesions covered by cell-free PLGA, exhibited areas of inflammation persistence and angiogenesis. The cell-seeded cell-seeded PLGA membrane exhibited complete reepithelialization after 6 days, with minor inflammatory infiltrate. Interestingly, the present work showed preclinical parameters of cachexia induced by chemotherapy for cancer treatment. Moreover, it showed an innovative approach by applying dressings consisting of electrospun PLGA with the addition of autologous mesenchymal cells for OM ulcerative lesions. This promising innovation will pave the way for future applications in oral mucosa lesions.

In Situ Preparation of Composite Scaffolds Based on Polyurethane and Hydroxyapatite Particles for Bone Tissue Engineering

This article details the in situ preparation of composite scaffolds using polyurethane (PU) and HAp (hydroxyapatite), focusing on the unique properties of buriti oil (Mauritia flexuosa L.) applicable to tissue engineering. PU derived from vegetable oils, particularly buriti oil, has shown promise in bone tissue repair due to its rich bioactive compounds. Buriti oil is an excellent candidate for manufacturing these materials as it is an oil rich in bioactive compounds such as carotenoids, tocopherols, and fatty acids, which have antioxidant and anti-inflammatory properties. Furthermore, buriti oil has oleic acid as its principal fatty acid, which has been investigated as an excellent HAp dispersant. This research aimed to synthesize PU scaffolds from a polyol derived from buriti oil and incorporate HAp in different concentrations into the polymeric matrix through in situ polymerization. The chemical composition of the materials obtained, the distribution of hydroxyapatite particles in the polyurethane matrix, and the thermal stability were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), and thermogravimetry (TGA). In addition, to investigate biocompatibility, MTT tests (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium) were conducted using rat bone-marrow-derived mesenchymal stem cells (BMMSC). Characterizations confirm the formation of PU and the presence of HAp in the polymeric matrix, and the materials did not show cytotoxicity.

Local Application of Minimally Manipulated Autologous Stromal Vascular Fraction (SVF) Reduces Inflammation and Improves Bilio-Biliary Anastomosis Integrity

Bilio-biliary anastomosis (BBA) is a critical surgical procedure that is performed with the objective of restoring bile duct continuity. This procedure is often required in cases where there has been an injury to the extrahepatic bile ducts or during liver transplantation. Despite advances in surgical techniques, the healing of BBA remains a significant challenge, with complications such as stricture formation and leakage affecting patient outcomes. The stromal vascular fraction (SVF), a heterogeneous cell population derived from adipose tissue, has demonstrated promise in regenerative medicine due to its rich content of stem cells, endothelial progenitor cells, and growth factors. The objective of this study was to evaluate the potential of locally administered autologous SVF to enhance the healing of BBAs. Bilio-biliary anastomosis was performed on a swine model (female Landrace pigs). Six swine were divided into two groups: the treatment group (n = 3) received a local application of autologous SVF around the anastomosis site immediately following BBA formation, while the control group (n = 3) received saline. The primary outcomes were assessed over an eight-week period post-surgery, and included anastomosis healing, stricture formation, and bile leakage. Histological analysis was performed to evaluate fibrosis, angiogenesis, and inflammation. Immunohistochemistry was conducted to assess healing-related markers (CD34, α-SMA) and the immunological microenvironment (CD3, CD10, tryptase). The SVF-treated group exhibited significantly enhanced healing of the BBA. Histological examination revealed increased angiogenesis and reduced fibrosis in the SVF group. Immunohistochemical staining demonstrated higher vascular density in the anastomosed area of the SVF-treated group (390 vs. 210 vessels per 1 mm2, p = 0.0027), as well as a decrease in wall thickness (1.9 vs. 1.0 mm, p = 0.0014). There were no statistically significant differences in mast cell presence (p = 0.40). Immunohistochemical staining confirmed the overexpression of markers associated with tissue repair. Local injections of autologous SVF at the site of BBA have been demonstrated to significantly enhance healing and promote tissue regeneration. These findings suggest that SVF could be a valuable adjunctive therapy in BBA surgery, potentially improving surgical outcomes. However, further investigation is needed to explore the clinical applicability and long-term benefits of this novel approach in clinical practice as a minimally manipulated cell application.

Advances in 3D printing technology for preparing bone tissue engineering scaffolds from biodegradable materials

Introduction

Bone tissue engineering (BTE) provides an effective repair solution by implanting osteoblasts or stem cells into biocompatible and biodegradable scaffolds to promote bone regeneration. In recent years, the rapid development of 3D bioprinting has enabled its extensive application in fabricating BTE scaffolds. Based on three-dimensional computer models and specialized "bio-inks," this technology offers new pathways for customizing BTE scaffolds. This study reviews the current status and future prospects of scaffold materials for BTE in 3D bioprinting.

Methods

This literature review collected recent studies on BTE and 3D bioprinting, analyzing the advantages and limitations of various scaffold materials for 3D printing, including bioceramics, metals, natural polymers, and synthetic polymers. Key characteristics like biocompatibility, mechanical properties, and degradation rates of these materials were systematically compared.

Results

The study highlights the diverse performances of materials used in BTE scaffolds. Bioceramics exhibit excellent biocompatibility but suffer from brittleness; metals offer high strength but may induce chronic inflammation; natural polymers are biocompatible yet have poor mechanical properties, while synthetic polymers offer strong tunability but may produce acidic by-products during degradation. Additionally, integrating 3D bioprinting with composite materials could enhance scaffold biocompatibility and mechanical properties, presenting viable solutions to current challenges.

Discussion

This review summarizes recent advances in 3D bioprinting for BTE scaffold applications, exploring the strengths and limitations of various materials and proposing composite material combinations to improve scaffold performance. By optimizing material selection and combinations, 3D bioprinting shows promise for creating customized scaffolds, offering a new technical route for clinical applications of BTE. This research provides a unique perspective and theoretical support for advancing 3D bioprinting technology in bone regeneration, outlining future directions for BTE materials and 3D bioprinting technology development.

Oncomatrix: Molecular Composition and Biomechanical Properties of the Extracellular Matrix in Human Tumors

The extracellular matrix is an organized three-dimensional network of protein-based molecules and other macromolecules that provide structural and biochemical support to tissues. Depending on its biochemical and structural properties, the extracellular matrix influences cell adhesion and signal transduction and, in general, can influence cell differentiation and proliferation through specific mechanisms of chemical and mechanical sensing. The development of body tissues during ontogenesis is accompanied by changes not only in cells but also in the composition and properties of the extracellular matrix. Similarly, tumor development in carcinogenesis is accompanied by a continuous change in the properties of the extracellular matrix of tumor cells, called ‘oncomatrix’, as the tumor matures, from the development of the primary focus to the stage of metastasis. In this paper, the characteristics of the composition and properties of the extracellular matrix of tumor tissues are considered, as well as changes to the composition and properties of the matrix during the evolution of the tumor and metastasis. The extracellular matrix patterns of tumor tissues can be used as biomarkers of oncological diseases as well as potential targets for promising anti-tumor therapies.

Nanotechnological Research for Regenerative Medicine: The Role of Hyaluronic Acid

Hyaluronic acid (HA) is a linear, anionic, non-sulfated glycosaminoglycan occurring in almost all body tissues and fluids of vertebrates including humans. It is a main component of the extracellular matrix and, thanks to its high water-holding capacity, plays a major role in tissue hydration and osmotic pressure maintenance, but it is also involved in cell proliferation, differentiation and migration, inflammation, immunomodulation, and angiogenesis. Based on multiple physiological effects on tissue repair and reconstruction processes, HA has found extensive application in regenerative medicine. In recent years, nanotechnological research has been applied to HA in order to improve its regenerative potential, developing nanomedical formulations containing HA as the main component of multifunctional hydrogels systems, or as core component or coating/functionalizing element of nanoconstructs. This review offers an overview of the various uses of HA in regenerative medicine aimed at designing innovative nanostructured devices to be applied in various fields such as orthopedics, dermatology, and neurology.

Self-healing hydrogels for enhancing chemotherapy drug efficacy: Advancements in anti-sarcoma and carcinoma therapies and clinical trial feasibility

•Site-specific administration is key for optimizing anticancer drug administration; self-healing hydrogels may allow this at reasonable costs and reproducibility.•Self-healing hydrogels have several real-world therapeutic applications, including drug administration.•Self-healing hydrogels are yet to be utilized for chemotherapy drug administration in clinical trials.•Clinical research on using self-healing hydrogels in anticancer therapeutics is feasible and valid compared to other advances in anticancer drug administration.

Silk Fibroin Materials: Biomedical Applications and Perspectives

The golden rule in tissue engineering is the creation of a synthetic device that simulates the native tissue, thus leading to the proper restoration of its anatomical and functional integrity, avoiding the limitations related to approaches based on autografts and allografts. The emergence of synthetic biocompatible materials has led to the production of innovative scaffolds that, if combined with cells and/or bioactive molecules, can improve tissue regeneration. In the last decade, silk fibroin (SF) has gained attention as a promising biomaterial in regenerative medicine due to its enhanced bio/cytocompatibility, chemical stability, and mechanical properties. Moreover, the possibility to produce advanced medical tools such as films, fibers, hydrogels, 3D porous scaffolds, non-woven scaffolds, particles or composite materials from a raw aqueous solution emphasizes the versatility of SF. Such devices are capable of meeting the most diverse tissue needs; hence, they represent an innovative clinical solution for the treatment of bone/cartilage, the cardiovascular system, neural, skin, and pancreatic tissue regeneration, as well as for many other biomedical applications. The present narrative review encompasses topics such as (i) the most interesting features of SF-based biomaterials, bare SF's biological nature and structural features, and comprehending the related chemo-physical properties and techniques used to produce the desired formulations of SF; (ii) the different applications of SF-based biomaterials and their related composite structures, discussing their biocompatibility and effectiveness in the medical field. Particularly, applications in regenerative medicine are also analyzed herein to highlight the different therapeutic strategies applied to various body sectors.

Current Advancement and Future Prospects: Biomedical Nanoengineering

Recent advancements in biomedicine have seen a significant reliance on nanoengineering, as traditional methods often fall short in harnessing the unique attributes of biomaterials. Nanoengineering has emerged as a valuable approach to enhance and enrich the performance and functionalities of biomaterials, driving research and development in the field. This review emphasizes the most prevalent biomaterials used in biomedicine, including polymers, nanocomposites, and metallic materials, and explores the pivotal role of nanoengineering in developing biomedical treatments and processes. Particularly, the review highlights research focused on gaining an in-depth understanding of material properties and effectively enhancing material performance through molecular dynamics simulations, all from a nanoengineering perspective.

The Evolution of Current Concept of the Reconstructive Ladder in Plastic Surgery: The Emerging Role of Translational Medicine

Plastic surgeons have used the reconstructive ladder for many decades as a standard directory for complex trauma reconstruction with the goal of repairing body structures and restoring functionality. This consists of different surgical maneuvers, such as secondary intention and direct tissue closure, as well as more complex methods such as local tissue transfer and free flap. The reconstructive ladder represents widely known options achievable for tissue reconstruction and wound closure that puts at the bottom rung the simplest methods of reconstruction and strengthens the complexity by moving upward. Regenerative medicine and surgery constitute a quickly spreading area of translational research that can be employed by minimally invasive surgical strategies, with the aim of regenerating cells and tissues in vivo in order to reestablish normal function through the intrinsic potential of cells, in combination with biomaterials and appropriate biochemical stimuli. These translational procedures have the aim of creating an appropriate microenvironment capable of supporting the physiological cellular function to generate the desired cells or tissues and to generate parenchymal, stromal, and vascular components on demand, and above all to produce intelligent materials capable of determining the fate of cells. Smart technologies have been grown that give extra "rungs" on the classic reconstructive ladder to integrate a more holistic, patient-based approach with improved outcomes. This commentary presents the evolution of the traditional concept of the reconstructive ladder in the field of plastic surgery into a new course with the aim of achieving excellent results for soft tissue reconstruction by applying innovative technologies and biologically active molecules for a wide range of surgical diseases.

Distribution, Typical Structure and Self-Assembly Properties of Collagen from Fish Skin and Bone

The source and type of collagen are crucial to its application, and both play a decisive role. Collagen was prepared from both tilapia skin and bone and skate skin and cartilage, named as CI-TI-s, CI-TI-b, CI-SK-s, and CII-SK-c, respectively. Types, distributions, structures, and self-assembly of collagen were studied. It showed that yellow collagen fibers from skin arranged longitudinally, while collagen fibers from skate cartilages displayed varying colors. CI-TI-s, CI-TI-b, CI-SK-s, and CII-SK-c showed the typical amide A (3316-3336 cm-1) and amide B (2929-2948 cm-1) in FTIR spectra. CI-TI-b and CII-SK-c showed 218-229 nm of UV absorption, 11.56-12.20 Å of d values in XRD, and 0.12-0.14 of Rpn values in CD. The thermal denaturation temperatures of CI-TI-s and CI-SK-s were 30.7 and 20.6 °C, respectively. The self-assembly of CI-TI-s and CII-SK-c were maximum at pH 7.2 and 7.4-7.6, respectively. The unique collagen peptides of tilapia and skate were GPSGPQGAVGATGPK, PAMPVPGPMGPMGPR, SPAMPVPGPMGPMGPR, GESGPSGPAGPAGPAGVR, SSGPPVPGPIGPMGPR, GLTGPIGVPGPPGAQGEK, GLAGPQGPR, and GLSGDPGVQGIK, respectively. The unique peptides of type I and type II collagen were GPTGEIGATGLAGAR, GVLGLTGMR, LGLTGMR, GEPGAAGPAGPSGPMGPR, SSGPPVPGPIGPMGPR, and GLSGDPGVQGIK, respectively.

Pitfalls and promises of bile duct alternatives: There is plenty of room in the regenerative surgery

Current abdominal surgery has several approaches for biliary reconstruction. However, the creation of functional and clinically applicable bile duct substitutes still represents an unmet need. In the paper by Miyazawa and colleagues, approaches to the creation of bile duct alternatives were summarized, and the reasons for the lack of development in this area were explained. The history of bile duct surgery since the nineteenth century was also traced, leading to the conclusion that the use of bioabsorbable materials holds promise for the creation of bile duct substitutes in the future. We suggest three ideas that may stimulate progress in the field of bile duct substitute creation. First, a systematic analysis of the causative factors leading to failure or success in the creation of bile duct substitutes may help to develop more effective approaches. Second, the regeneration of a bile duct is delicately balanced between epithelialization and subsequent submucosal maturation within limited time frames, which may be more apparent when using quantitative models to estimate outcomes. Third, the utilization of the organism's endogenous regeneration abilities may enhance the creation of bile duct substitutes. We are convinced that an interdisciplinary approach, including quantitative methods, machine learning, and deep retrospective analysis of the causes that led to success and failure in studies on the creation of bile duct substitutes, holds great value. Additionally, more attention should be directed towards the balance of epithelialization and submucosal maturation rates, as well as induced angiogenesis. These ideas deserve further investigation to pave the way for bile duct restoration with physiologically relevant outcomes.

Anatomical Tissue Engineering of the Anterior Cruciate Ligament Entheses

The firm integration of anterior cruciate ligament (ACL) grafts into bones remains the most demanding challenge in ACL reconstruction, since graft loosening means graft failure. For a functional-tissue-engineered ACL substitute to be realized in future, robust bone attachment sites (entheses) have to be re-established. The latter comprise four tissue compartments (ligament, non-calcified and calcified fibrocartilage, separated by the tidemark, bone) forming a histological and biomechanical gradient at the attachment interface between the ACL and bone. The ACL enthesis is surrounded by the synovium and exposed to the intra-articular micromilieu. This review will picture and explain the peculiarities of these synovioentheseal complexes at the femoral and tibial attachment sites based on published data. Using this, emerging tissue engineering (TE) strategies addressing them will be discussed. Several material composites (e.g., polycaprolactone and silk fibroin) and manufacturing techniques (e.g., three-dimensional-/bio-printing, electrospinning, braiding and embroidering) have been applied to create zonal cell carriers (bi- or triphasic scaffolds) mimicking the ACL enthesis tissue gradients with appropriate topological parameters for zones. Functionalized or bioactive materials (e.g., collagen, tricalcium phosphate, hydroxyapatite and bioactive glass (BG)) or growth factors (e.g., bone morphogenetic proteins [BMP]-2) have been integrated to achieve the zone-dependent differentiation of precursor cells. However, the ACL entheses comprise individual (loading history) asymmetric and polar histoarchitectures. They result from the unique biomechanical microenvironment of overlapping tensile, compressive and shear forces involved in enthesis formation, maturation and maintenance. This review should provide a road map of key parameters to be considered in future in ACL interface TE approaches.

Electrospun Drug-Loaded and Gene-Loaded Nanofibres: The Holy Grail of Glioblastoma Therapy?

To date, GBM remains highly resistant to therapies that have shown promising effects in other cancers. Therefore, the goal is to take down the shield that these tumours are using to protect themselves and proliferate unchecked, regardless of the advent of diverse therapies. To overcome the limitations of conventional therapy, the use of electrospun nanofibres encapsulated with either a drug or gene has been extensively researched. The aim of this intelligent biomaterial is to achieve a timely release of encapsulated therapy to exert the maximal therapeutic effect simultaneously eliminating dose-limiting toxicities and activating the innate immune response to prevent tumour recurrence. This review article is focused on the developing field of electrospinning and aims to describe the different types of electrospinning techniques in biomedical applications. Each technique describes how not all drugs or genes can be electrospun with any method; their physico-chemical properties, site of action, polymer characteristics and the desired drug or gene release rate determine the strategy used. Finally, we discuss the challenges and future perspectives associated with GBM therapy.

Overview of Electrospinning for Tissue Engineering Applications

Tissue engineering (TE) is an emerging field of study that incorporates the principles of biology, medicine, and engineering for designing biological substitutes to maintain, restore, or improve tissue functions with the goal of avoiding organ transplantation. Amongst the various scaffolding techniques, electrospinning is one of the most widely used techniques to synthesise a nanofibrous scaffold. Electrospinning as a potential tissue engineering scaffolding technique has attracted a great deal of interest and has been widely discussed in many studies. The high surface-to-volume ratio of nanofibres, coupled with their ability to fabricate scaffolds that may mimic extracellular matrices, facilitates cell migration, proliferation, adhesion, and differentiation. These are all very desirable properties for TE applications. However, despite its widespread use and distinct advantages, electrospun scaffolds suffer from two major practical limitations: poor cell penetration and poor load-bearing applications. Furthermore, electrospun scaffolds have low mechanical strength. Several solutions have been offered by various research groups to overcome these limitations. This review provides an overview of the electrospinning techniques used to synthesise nanofibres for TE applications. In addition, we describe current research on nanofibre fabrication and characterisation, including the main limitations of electrospinning and some possible solutions to overcome these limitations.

Fabrication, Microstructures and Sensor Applications of Highly Ordered Electrospun Nanofibers: A Review

The review summarizes the fabrication, microstructures, and sensor applications of highly ordered electrospun nanofibers. In the traditional electrospinning process, electrospun nanofibers usually have disordered or random microstructures due to the chaotic oscillation of the electrospinning jet. Different electrospinning methods can be formed by introducing external forces, such as magnetic, electric, or mechanical forces, and ordered nanofibers can be collected. The microstructures of highly ordered nanofibers can be divided into three categories: uniaxially ordered nanofibers, biaxially ordered nanofibers and ordered scaffolds. The three microstructures are each characterized by being ordered in different dimensions. The regulation and control of the ordered microstructures can promote electrospun nanofibers' mechanical and dielectric strength, surface area and chemical properties. Highly ordered electrospun nanofibers have more comprehensive applications than disordered nanofibers do in effect transistors, gas sensors, reinforced composite materials and tissue engineering. This review also intensively summarizes the applications of highly ordered nanofibers in the sensor field, such as pressure sensors, humidity sensors, strain sensors, gas sensors, and biosensors.