Fabrication and assessment of a novel hybrid scaffold consisted of polyurethane-gellan gum-hyaluronic acid-glucosamine for meniscus tissue engineering

A review of recent advances in tissue engineering scaffolds for meniscus repair

The meniscus, a critical load-bearing structure between the femur and the tibia, plays a key role in the functioning of the knee joint by distributing mechanical stress and minimizing friction. A brief overview of the anatomical characteristics and biomechanical functions of the meniscus is provided in this review, followed by a discussion of recent developments in tissue engineering scaffolds for meniscus repair over the past five years. The classification of scaffolds is based on the materials with an analysis of their respective advantages and limitations. The challenges associated with meniscal tissue engineering are summarized and potential research directions are proposed to guide the development of more effective regenerative strategies.

Generating New Meniscus Therapies via Recent Breakthroughs in Development, Model Systems, and Clinical Diagnostics

Over 850,000 surgeries are performed to treat meniscal injuries each year in the United States. Even with repair, patients are likely to develop osteoarthritis (OA) within the next two decades. There is a pressing clinical need to improve meniscal repair procedures to restore tissue function and prevent joint degeneration later in life. Here we present a review of recently published articles (2020-2024) spanning basic science, translational, and clinical studies to highlight new advances in meniscus research across development, animal models, finite element models, and clinical interventions. Key progenitor cell populations and vascularity changes have been identified in human meniscus tissue development, aging, and degeneration with implications for novel tissue repair strategies. The use of animal and finite element models has expanded our understanding of meniscus tissue function and evaluated new therapies in preclinical studies. Further, advances in clinical diagnostics with machine learning models and surgical techniques have shed light on evidence-based practices for improving patient outcomes. We discuss across multiple length scales (micro-, meso-, macro-) the structure-function relationship of the meniscus in development and disease, recent advances in models and tools to study the meniscus, knowledge gaps in the field, persisting challenges in clinical treatments and assessments, and the translation of basic science therapies into the clinic.

A hybrid 3D-printed and electrospun bilayer pharmaceutical membrane based on polycaprolactone/chitosan/polyvinyl alcohol for wound healing applications

Skin injuries resulting from physical trauma pose significant health risks, necessitating advanced wound care solutions. This investigation introduces an innovative bilayer wound dressing composed of 3D-printed propolis-coated polycaprolactone (PCL/PP) and an electrospun composite of polyvinyl alcohol, chitosan, polycaprolactone, and diltiazem (PVA/CTS/PCL/DTZ). SEM analysis revealed a bilayer structure with 89.23 ± 51.47 % porosity and uniformly distributed nanofibers. The scaffold tensile strength, with pore sizes of 100, 300, and 500 μm, was comparable to native skin. However, smaller pore sizes reduced water vapor transmission from 4211.59 ± 168.53 to 2358.49 ± 203.63 g/m2. The incorporation of DTZ lowered the contact angle to 35.23 ± 3.65°, while the addition of PCL reduced the degradation rate and modulated the release of DTZ by approximately 50 %. Moreover, lower pH increased the degradation rate and decreased swelling. The inclusion of propolis enhanced antibacterial activity, and 10 % DTZ promoted the viability, proliferation, and migration of fibroblasts and adipose-derived stem cells. However, increasing DTZ concentration to 12 % reduced cell viability. In vivo tests on rats demonstrated effective wound healing and anti-inflammatory properties of the bilayer samples. Regarding the aforementioned results, the PCL/PP-PVA/CTS/PCL/DTZ (10 % w/w) bilayer wound dressing is a promising candidate for wound healing applications.

A comprehensive bench-to-bed look into the application of gamma-sterilized 3D-printed polycaprolactone/hydroxyapatite implants for craniomaxillofacial defects, an in vitro, in vivo, and clinical study

This study investigates the safety and efficacy of 3D-printed polycaprolactone/hydroxyapatite (PCL/HA) scaffolds for patient-specific cranioplasty surgeries, employing liquid deposition modeling (LDM) technology. This research is pioneering as it explores the impact of gamma radiation on PCL/HA scaffolds and utilizes printing ink with the highest content of HA known in the composite. The mechanical, morphological, and macromolecular stability of the gamma-sterilized scaffolds were verified before implantation. Subsequent research involving animal subjects was conducted to explore the effects of sterilized implants. Eventually, three clinical cases were selected for the implantation studies as part of a phase 1 non-randomized open-label clinical trial. It was shown that a 25 kGy gamma-ray dose for sterilizing the printed implants did not alter the required geometrical precision of the printed implants. The implants exhibited well-distributed HA and strength comparable to cancellous bone. Gamma radiation reduced hydrophobicity and water uptake capacity without inducing pyrogenic or inflammatory responses. Personalized PCL/HA substitutes successfully treated various craniomaxillofacial defects, including trauma-induced facial asymmetry and congenital deformities. HA nanoparticles in the ink stimulated significant osteoconductive responses within three months of implantation. Moreover, the results revealed that while larger implants may exhibit a slower bone formation response in comparison to smaller implants, they generally had an acceptable rate and volume of bone formation. This clinical trial suggests the application of a sterilized PCL/HA composite for craniomaxillofacial surgery is safe and could be considered as a substitute for autologous bone.

Advances in tissue engineering of gellan gum-based hydrogels

Gellan Gum (GG) is a large, naturally occurring, linear polysaccharide with a similar structure and biological properties to the extracellular matrix. It's appropriate as a matrix material for the development of different composite materials due to its biocompatibility, biodegradability, and injectability. Hydrogels made from GG have found various applications in the field of Tissue Engineering (TE) in recent years after being mixed with a variety of other organic and inorganic components. These composites are considered multifunctional developing biomaterials because of their impressive mechanical capabilities, biocompatibility, low cytotoxicity, etc. This review focuses on the emerging advances of GG-based hydrogels in TE, providing an overview of the applications of different types of GG-based composite materials in bone TE, cartilage TE, nervous TE, retina TE, and other fields. Moreover, the investigations of GG-based hydrogels as bioink components for 3D bioprinting in TE will be elucidated. This review offers general guidance for the development of biomaterials related to GG, as well as ideas for future clinical diagnosis and treatment.

Recent advances in 3D bioprinted cartilage-mimicking constructs for applications in tissue engineering

Human cartilage tissue can be categorized into three types: hyaline cartilage, elastic cartilage and fibrocartilage. Each type of cartilage tissue possesses unique properties and functions, which presents a significant challenge for the regeneration and repair of damaged tissue. Bionics is a discipline in which humans study and imitate nature. A bionic strategy based on comprehensive knowledge of the anatomy and histology of human cartilage is expected to contribute to fundamental study of core elements of tissue repair. Moreover, as a novel tissue-engineered technology, 3D bioprinting has the distinctive advantage of the rapid and precise construction of targeted models. Thus, by selecting suitable materials, cells and cytokines, and by leveraging advanced printing technology and bionic concepts, it becomes possible to simultaneously realize multiple beneficial properties and achieve improved tissue repair. This article provides an overview of key elements involved in the combination of 3D bioprinting and bionic strategies, with a particular focus on recent advances in mimicking different types of cartilage tissue.

Progress and opportunities in Gellan gum-based materials: A review of preparation, characterization and emerging applications

Gellan gum, a microbial exopolysaccharide, is biodegradable and has potential to fill several key roles in many fields from food to pharmacy, biomedicine and tissue engineering. In order to improve the physicochemical and biological properties of gellan gum, some researchers take advantage of numerous hydroxyl groups and the free carboxyl present in each repeating unit. As a result, design and development of gellan-based materials have advanced significantly. The goal of this review is to provide a summary of the most recent, high-quality research trends that have used gellan gum as a polymeric component in the design of numerous cutting-edge materials with applications in various fields.

Anatomically and Biomechanically Relevant Monolithic Total Disc Replacement Made of 3D-Printed Thermoplastic Polyurethane

Various implant treatments, including total disc replacements, have been tried to treat lumbar intervertebral disc (IVD) degeneration, which is claimed to be the main contributor of lower back pain. The treatments, however, come with peripheral issues. This study proposes a novel approach that complies with the anatomical features of IVD, the so-called monolithic total disc replacement (MTDR). As the name suggests, the MTDR is a one-part device that consists of lattice and rigid structures to mimic the nucleus pulposus and annulus fibrosus, respectively. The MTDR can be made of two types of thermoplastic polyurethane (TPU 87A and TPU 95A) and fabricated using a 3D printing approach: fused filament fabrication. The MTDR design involves two configurations-the full lattice (FLC) and anatomy-based (ABC) configurations. The MTDR is evaluated in terms of its physical, mechanical, and cytotoxicity properties. The physical characterization includes the geometrical evaluations, wettability measurements, degradability tests, and swelling tests. The mechanical characterization comprises compressive tests of the materials, an analytical approach using the Voigt model of composite, and a finite element analysis. The cytotoxicity assays include the direct assay using hemocytometry and the indirect assay using a tetrazolium-based colorimetric (MTS) assay. The geometrical evaluation shows that the fabrication results are tolerable, and the two materials have good wettability and low degradation rates. The mechanical characterization shows that the ABC-MTDR has more similar mechanical properties to an IVD than the FLC-MTDR. The cytotoxicity assays prove that the materials are non-cytotoxic, allowing cells to grow on the surfaces of the materials.

Research Progress on Emerging Polysaccharide Materials Applied in Tissue Engineering

The development and application of polysaccharide materials are popular areas of research. Emerging polysaccharide materials have been widely used in tissue engineering fields such as in skin trauma, bone defects, cartilage repair and arthritis due to their stability, good biocompatibility and reproducibility. This paper reviewed the recent progress of the application of polysaccharide materials in tissue engineering. Firstly, we introduced polysaccharide materials and their derivatives and summarized the physicochemical properties of polysaccharide materials and their application in tissue engineering after modification. Secondly, we introduced the processing methods of polysaccharide materials, including the processing of polysaccharides into amorphous hydrogels, microspheres and membranes. Then, we summarized the application of polysaccharide materials in tissue engineering. Finally, some views on the research and application of polysaccharide materials are presented. The purpose of this review was to summarize the current research progress on polysaccharide materials with special attention paid to the application of polysaccharide materials in tissue engineering.

Gellan gum modified hyaluronic acid hydrogel as viscosupplement with lubrication maintenance and enzymatic resistance

Osteoarthritis (OA) is a common disease caused by damage to articular cartilage and underlying bone tissues. Early OA can be treated by intra-articular injection of viscosupplements to restore the lost...