Carbon nanofiber amalgamated 3D poly-ε-caprolactone scaffold functionalized porous-nanoarchitectures for human meniscal tissue engineering: In vitro and in vivo biocompatibility studies

The biomechanical properties of human menisci: A systematic review

Biomechanical characterization of meniscal tissue ex vivo remains a critical need, particularly for the development of suitable meniscus replacements or therapeutic strategies that target the native mechanical properties of the meniscus. To date, a huge variety of test configurations and protocols have been reported, making it extremely difficult to compare the respective outcome parameters, thereby leading to misinterpretation. Therefore, the purpose of this systematic review was to identify test-specific parameters that contribute to uncertainties in the determination of mechanical properties of the human meniscus and its attachments, which derived from common quasi-static and dynamic tests in tension, compression, and shear. Strong evidence was found that the determined biomechanical properties vary significantly depending on the specific test parameters, as indicated by up to tenfold differences in both tensile and compressive properties. Test mode (stress relaxation, creep, cyclic) and configuration (unconfined, confined, in-situ), specimen shape and dimensions, preconditioning regimes, loading rates, post-processing of experimental data, and specimen age and degeneration were identified as the most critical parameters influencing the outcome measures. In conclusion, this work highlights an unmet need for standardization and reporting guidelines to facilitate comparability and may prove beneficial for evaluating the mechanical properties of novel meniscus constructs. STATEMENT OF SIGNIFICANCE: The biomechanical properties of the human meniscus have been studied extensively over the past decades. However, it remains unclear to what extent both test protocol and specimen-related differences are responsible for the enormous variability in material properties. Therefore, this systematic review analyzes the biomechanical properties of the human meniscus in the context of the underlying testing protocol. The most sensitive parameters affecting the determination of mechanical properties were identified and critically discussed. Currently, it is of utmost importance for scientists evaluating potential meniscal scaffolds and biomaterials to have a control group rather than a direct comparison to the literature. Standardization of both test procedures and reporting requirements is needed to improve and accelerate the development of meniscal replacement constructs.

Carbonised Human Hair Incorporated in Agar/KGM Bioscaffold for Tissue Engineering Application: Fabrication and Characterisation

Carbon derived from biomass waste usage is rising in various fields of application due to its availability, cost-effectiveness, and sustainability, but it remains limited in tissue engineering applications. Carbon derived from human hair waste was selected to fabricate a carbon-based bioscaffold (CHAK) due to its ease of collection and inexpensive synthesis procedure. The CHAK was fabricated via gelation, rapid freezing, and ethanol immersion and characterised based on their morphology, porosity, Fourier transforms infrared (FTIR), tensile strength, swelling ability, degradability, electrical conductivity, and biocompatibility using Wharton’s jelly-derived mesenchymal stem cells (WJMSCs). The addition of carbon reduced the porosity of the bioscaffold. Via FTIR analysis, the combination of carbon, agar, and KGM was compatible. Among the CHAK, the 3HC bioscaffold displayed the highest tensile strength (62.35 ± 29.12 kPa). The CHAK also showed excellent swelling and water uptake capability. All bioscaffolds demonstrated a slow degradability rate (<50%) after 28 days of incubation, while the electrical conductivity analysis showed that the 3AHC bioscaffold had the highest conductivity compared to other CHAK bioscaffolds. Our findings also showed that the CHAK bioscaffolds were biocompatible with WJMSCs. These findings showed that the CHAK bioscaffolds have potential as bioscaffolds for tissue engineering applications.

Synthesis, surface modifications, and biomedical applications of carbon nanofibers: Electrospun vs vapor-grown carbon nanofibers

Engineered nanostructures are materials with promising properties, enabled by precise design and fabrication, as well as size-dependent effects. Biomedical applications of nanomaterials in disease-specific prevention, diagnosis, treatment, and recovery monitoring require precise, specific, and sophisticated approaches to yield effective and long-lasting favorable outcomes for patients. In this regard, carbon nanofibers (CNFs) have been indentified due to their interesting properties, such as good mechanical strength, high electrical conductivity, and desirable morphological features. Broadly speaking, CNFs can be categorized as vapor-grown carbon nanofibers (VGCNFs) and carbonized CNFs (e.g., electrospun CNFs), which have distinct microstructure, morphologies, and physicochemical properties. In addition to their physicochemical properties, VGCNFs and electrospun CNFs have distinct performances in biomedicine and have their own pros and cons. Indeed, several review papers in the literature have summarized and discussed the different types of CNFs and their performances in the industrial, energy, and composites areas. Crucially however, there is room for a comprehensive review paper dealing with CNFs from a biomedical point of view. The present work therefore, explored various types of CNFs, their fabrication and surface modification methods, and their applications in the different branches of biomedical engineering.

Modelling of Stem Cells Microenvironment Using Carbon-Based Scaffold for Tissue Engineering Application-A Review

A scaffold is a crucial biological substitute designed to aid the treatment of damaged tissue caused by trauma and disease. Various scaffolds are developed with different materials, known as biomaterials, and have shown to be a potential tool to facilitate in vitro cell growth, proliferation, and differentiation. Among the materials studied, carbon materials are potential biomaterials that can be used to develop scaffolds for cell growth. Recently, many researchers have attempted to build a scaffold following the origin of the tissue cell by mimicking the pattern of their extracellular matrix (ECM). In addition, extensive studies were performed on the various parameters that could influence cell behaviour. Previous studies have shown that various factors should be considered in scaffold production, including the porosity, pore size, topography, mechanical properties, wettability, and electroconductivity, which are essential in facilitating cellular response on the scaffold. These interferential factors will help determine the appropriate architecture of the carbon-based scaffold, influencing stem cell (SC) response. Hence, this paper reviews the potential of carbon as a biomaterial for scaffold development. This paper also discusses several crucial factors that can influence the feasibility of the carbon-based scaffold architecture in supporting the efficacy and viability of SCs.

Thermal Stability and Dynamic Mechanical Properties of Poly(ε-caprolactone)/Chitosan Composite Membranes

Poly (ε-caprolactone) (PCL) and chitosan (CS) are widely used as biodegradable and biocompatible polymers with desirable properties for tissue engineering applications. Composite membranes (CS-PCL) with various blend ratios (CS:PCL, w/w) of 0:100, 5:95, 10:90, 15:85, 20:80, and 100:0 were successfully prepared by lyophilization. The thermal stabilities of the CS-PCL membranes were systematically characterized by thermogravimetric analysis (TG), dynamic thermogravimetry (DTG), and differential scanning calorimetry (DSC). It was shown that the blend ratio of PCL and CS had a significant effect on the thermal stability, hydrophilicity, and dynamic mechanical viscoelasticity of the CS-PCL membranes. All the samples in the experimental range exhibited high elasticity at low temperature and high viscosity at high temperatures by dynamic mechanical thermal analysis (DMTA). The performances of the CS-PCL membranes were at optimum levels when the blend ratio (w/w) was 10:90. The glass transition temperature of the CS-PCL membranes increased from 64.8 °C to 76.6 °C compared to that of the pure PCL, and the initial thermal decomposition temperature reached 86.7 °C. The crystallinity and porosity went up to 29.97% and 85.61%, respectively, while the tensile strength and elongation at the breakage were 20.036 MPa and 198.72%, respectively. Therefore, the 10:90 (w/w) blend ratio of CS/PCL is recommended to prepare CS-PCL membranes for tissue engineering applications.

A review of strategies for development of tissue engineered meniscal implants

The meniscus is a key stabilizing tissue of the knee that facilitates proper tracking and movement of the knee joint and absorbs stresses related to physical activity. This review article describes the biology, structure, and functions of the human knee meniscus, common tears and repair approaches, and current research and development approaches using modern methods to fabricate a scaffold or tissue engineered meniscal replacement. Meniscal tears are quite common, often resulting from sports or physical training, though injury can result without specific contact during normal physical activity such as bending or squatting. Meniscal injuries often require surgical intervention to repair, restore basic functionality and relieve pain, and severe damage may warrant reconstruction using allograft transplants or commercial implant devices. Ongoing research is attempting to develop alternative scaffold and tissue engineered devices using modern fabrication techniques including three-dimensional (3D) printing which can fabricate a patient-specific meniscus replacement. An ideal meniscal substitute should have mechanical properties that are close to that of natural human meniscus, and also be easily adapted for surgical procedures and fixation. A better understanding of the organization and structure of the meniscus as well as its potential points of failure will lead to improved design approaches to generate a suitable and functional replacement.

A comprehensive review summarizing the recent biomedical applications of functionalized carbon nanofibers

Since the discovery and fabrication of carbon nanofibers (CNFs) over a decade ago, scientists foster to discover novel myriad potential applications for this material in both biomedicine and industry. The unique economic viability, mechanical, electrical, optical, thermal, and structural properties of CNFs led to their rapid emergence. CNFs become an artificial intelligence platform for different uses, including a wide range of biomedical applications. Furthermore, CNFs have exceptionally large surface areas that make them flexible for tailoring and functionalization on demand. This review highlights the recent progress and achievements of CNFs in a wide range of biomedical fields, including cancer therapy, biosensing, tissue engineering, and wound dressing. Besides the synthetic techniques of CNFs, their potential toxicity and limitations, as biomaterials in real clinical settings, will be presented. This review discusses CNF's future investigations in other biomedical fields, including gene delivery and bioimaging and CNFs risk assessment.

Effect of nanocomposite coating and biomolecule functionalization on silk fibroin based conducting 3D braided scaffolds for peripheral nerve tissue engineering

In this work, the effects of carbon nanofiber (CNF) dispersed poly-ε-caprolactone (PCL) nanocomposite coatings and biomolecules functionalization on silk fibroin based conducting braided nerve conduits were studied for enhancing Neuro 2a cellular activities. A unique combination of biomolecules (UCM) and varying concentrations of CNF (5, 7.5, 10% w/w) were dispersed in 10% (w/v) PCL solution for coating on degummed silk threads. The coated silk threads were braided to develop the scaffold structure. As the concentration of CNF increased in the coating, the electrical impedance decreased up to 400 Ω indicating better conductivity. The tensile and dynamic mechanical property analysis showed better mechanical properties in CNF coated samples. In vitro cytocompatibility analysis proved the non-toxicity of the developed braided conduits. Cell attachment, growth and proliferation were significantly enhanced on the biomolecule functionalized nanocomposite coated silk braided structure, exhibiting their potential for peripheral nerve regeneration and recovery.

Characterizations and interfacial reinforcement mechanisms of multicomponent biopolymer based scaffold

It is difficult for a single component biopolymer to meet the requirements of scaffold at present. The development of multicomponent biopolymer based scaffold provides an effective method to solve the issue based on the advantages of each kind of the biomaterials. However, the compatibility between different components might be very poor due to the difficulties in forming strong interfacial bonding, and thereby significantly degrading the integrated mechanical properties of the scaffold. In recent years, interface phase introduction, surface modification and in situ growth have been the major strategies for enhancing interfacial bonding. This article presents a comprehensive overview on the research in the area of constructing multicomponent biopolymer based scaffold and reinforcing their interfacial properties, and more importantly, the interfacial bonding mechanisms are systematically summarized. Detailly, interface phase introduction can build a bridge between biopolymer and other components to form strong interface bonding with the two phases under the action of interface phase. Surface modification can graft organic molecules or polymers containing functional groups onto other components to crosslink with biopolymer. In situ growth can directly in situ synthesize other components with the action of nucleating agent serving as an adherent platform for the nucleation and growth of other components to biopolymer surface by chemical bonding. In addition, the mechanical properties (including strength and modulus) and biological properties (including bioactivity, cytocompatibility and biosensing in vitro, and tissue compatibility, bone regeneration capacity in vivo) of multicomponent biopolymer based scaffold after interfacial reinforcing are also reviewed and discussed. Finally, suggestions for further research are given with highlighting the need for specific investigations to assess the interface formation, structure, properties, and more in vivo studies of scaffold before applications.

The enhanced osteogenesis and osteointegration of 3-DP PCL scaffolds via structural and functional optimization using collagen networks

Optimal balance between biological activity and mechanical stability should be meticulously considered during scaffold design for bone tissue engineering applications. To fabricate an individualized construct with biomechanical and biological functionality for bone tissue regeneration, a polycaprolactone–collagen (PCL–COL) composite construct was developed through the combination of three-dimensional printing (3-DP) technology and biomimetic collagen matrix incorporation, with a 3-DP PCL framework maintaining the mechanical stability and a porous collagen matrix improving the biological activity. The results indicate that the compressive modulus of the composite constructs increased synergistically (over 40 MPa), providing sufficient mechanical support during new bone formation. On the other hand, the collagen matrix with a micro-porous architecture structurally increased scaffold areas and provided cellular adhesion sites, allowing for the functional construction of a favorable 3D microenvironment for BMSC adhesion, proliferation and extracellular matrix production. Moreover, critical-sized long bone defect (CSD) implantation demonstrated that the optimized composite constructs could promote bone tissue regeneration (5.5-fold) and bone-material osteointegration (4.7-fold), and decrease fibrosis encapsulation, compared to pristine PCL. The results indicate that these biomimetically ornamented PCL–COL constructs exhibit favorable mechanical properties and biological functionality, demonstrating great potential as an effective bone graft substitute for bone defect treatment. Meanwhile, they can also harness the advantages of 3-DP technology and a collagen-based functionalized strategy, facilitating the creation of customized and functional PCL–COL constructs for clinical translation.

Optimal balance between biological activity and mechanical stability should be meticulously considered during scaffold design for bone tissue engineering applications.