Mineralization of electrospun gelatin/CaCO3 composites: A new approach for dental applications

Application and Development of Electrospun Nanofiber Scaffolds for Bone Tissue Engineering

Nanofiber scaffolds have gained significant attention in the field of bone tissue engineering. Electrospinning, a straightforward and efficient technique for producing nanofibers, has been extensively researched. When used in bone tissue engineering scaffolds, electrospun nanofibers with suitable surface properties promote new bone tissue growth and enhance cell adhesion. Recent advancements in electrospinning technology have provided innovative approaches for scaffold fabrication in bone tissue engineering. This review comprehensively examines the utilization of electrospun nanofibers in bone tissue engineering scaffolds and evaluates the relevant literature. The review begins by presenting the fundamental principles and methodologies of electrospinning. It then discusses various materials used in the production of electrospun nanofiber scaffolds for bone tissue engineering, including natural and synthetic polymers, as well as certain inorganic materials. The challenges associated with these materials are also described. The review focuses on novel electrospinning techniques for scaffold construction in bone tissue engineering, such as multilayer nanofibers, multifluid electrospinning, and the integration of electrospinning with other methods. Recent advancements in electrospinning technology have enabled the fabrication of precisely aligned nanofiber scaffolds with nanoscale architectures. These innovative methods also facilitate the fabrication of biomimetic structures, wherein bioactive substances can be incorporated and released in a controlled manner for drug delivery purposes. Moreover, they address issues encountered with traditional electrospun nanofibers, such as mechanical characteristics and biocompatibility. Consequently, the development and implementation of novel electrospinning technologies have revolutionized scaffold fabrication for bone tissue engineering.

Current application and modification strategy of marine polysaccharides in tissue regeneration: A review

Marine polysaccharides (MPs) are exceptional bioactive materials that possess unique biochemical mechanisms and pharmacological stability, making them ideal for various tissue engineering applications. Certain MPs, including agarose, alginate, carrageenan, chitosan, and glucan have been successfully employed as biological scaffolds in animal studies. As carriers of signaling molecules, scaffolds can enhance the adhesion, growth, and differentiation of somatic cells, thereby significantly improving the tissue regeneration process. However, the biological benefits of pure MPs composite scaffold are limited. Therefore, physical, chemical, enzyme modification and other methods are employed to expand its efficacy. Chemically, the structural properties of MPs scaffolds can be altered through modifications to functional groups or molecular weight reduction, thereby enhancing their biological activities. Physically, MPs hydrogels and sponges emulate the natural extracellular matrix, creating a more conducive environment for tissue repair. The porosity and high permeability of MPs membranes and nanomaterials expedite wound healing. This review explores the distinctive properties and applications of select MPs in tissue regeneration, highlighting their structural versatility and biological applicability. Additionally, we provide a brief overview of common modification strategies employed for MP scaffolds. In conclusion, MPs have significant potential and are expected to be a novel regenerative material for tissue engineering.

MicroRNA-activated hydrogel scaffold generated by 3D printing accelerates bone regeneration

Bone defects remain a major threat to human health and bone tissue regeneration has become a prominent clinical demand worldwide. The combination of microRNA (miRNA) therapy with 3D printed scaffolds has always posed a challenge. It can mimic physiological bone healing processes, in which a biodegradable scaffold is gradually replaced by neo-tissue, and the sustained release of miRNA plays a vital role in creating an optimal osteogenic microenvironment, thus achieving promising bone repair outcomes. However, the balance between two key factors - scaffold degradation behavior and miRNA release profile - on osteogenesis and bone formation is still poorly understood. Herein, we construct a series of miRNA-activated hydrogel scaffolds (MAHSs) generated by 3D printing with different crosslinking degree to screened the interplay between scaffold degradation and miRNA release in the osteoinduction activity both in vitro and in vivo. Although MAHSs with a lower crosslinking degree (MAHS-0 and MAHS-0.25) released a higher amount of miR-29b in a sustained release profile, they degraded too fast to provide prolonged support for cell and tissue ingrowth. On the contrary, although the slow degradation of MAHSs with a higher crosslinking degree (MAHS-1 and MAHS-2.5) led to insufficient release of miR-29b, their adaptable degradation rate endowed them with more efficient osteoinductive behavior over the long term. MAHS-1 gave the most well-matched degradation rate and miR-29b release characteristics and was identified as the preferred MAHSs for accelerated bone regeneration. This study suggests that the bio-adaptable balance between scaffold degradation behavior and bioactive factors release profile plays a critical role in bone regeneration. These findings will provide a valuable reference about designing miRNAs as well as other bioactive molecules activated scaffold for tissue regeneration.

Recent advances in polymer scaffolds for biomedical applications

The review provides insights into current advancements in electrospinning-assisted manufacturing for optimally designing biomedical devices for their prospective applications in tissue engineering, wound healing, drug delivery, sensing, and enzyme immobilization, and others. Further, the evolution of electrospinning-based hybrid biomedical devices using a combined approach of 3 D printing and/or film casting/molding, to design dimensionally stable membranes/micro-nanofibrous assemblies/patches/porous surfaces, etc. is reported. The influence of various electrospinning parameters, polymeric material, testing environment, and other allied factors on the morphological and physico-mechanical properties of electrospun (nano-/micro-fibrous) mats (EMs) and fibrous assemblies have been compiled and critically discussed. The spectrum of operational research and statistical approaches that are now being adopted for efficient optimization of electrospinning process parameters so as to obtain the desired response (physical and structural attributes) has prospectively been looked into. Further, the present review summarizes some current limitations and future perspectives for modeling architecturally novel hybrid 3 D/selectively textured structural assemblies, such as biocompatible, non-toxic, and bioresorbable mats/scaffolds/membranes/patches with apt mechanical stability, as biological substrates for various regenerative and non-regenerative therapeutic devices.

Biocompatible PCL-nanofibers scaffold with immobilized fibronectin and laminin for neuronal tissue regeneration

Recent advances in regenerative medicine have given hope in overcoming and rehabilitating complex medical conditions. In this regard, the biopolymer poly-ε-caprolactone (PCL) may be a promising candidate for tissue regeneration, despite lacking the essential bioactivity. The present study used PCL nanofibers (NFs) scaffold decorated with the extracellular matrix proteins fibronectin and laminin combined for neuronal regeneration. The potential for the dual proteins to support neuronal cells and promote axonal growth was investigated. Two NFs scaffolds were produced with PLC concentrations of 12% or 15%. Under scanning electron microscopy, both scaffolds evidenced uniform diameter distribution in the range of 358 nm and 887 nm, respectively, with >80% porosity. The Brunauer-Emmett-Teller (BET) test confirmed that the fabricated NFs mats had a high surface area, especially for the 12% NFs with 652 m²/g compared to 254 m²/g for the 15% NFs. The proteins of interest were successfully conjugated to the 12% PCL scaffold through chemical carbodiimide reaction as confirmed by Fourier-transform infrared spectroscopy. The addition of fibronectin and laminin together was shown to be the most favorable for cellular attachment and elongation of neuroblastoma SH-SY5Y cells compared to other formulations. Light microscopy revealed longer neurite outgrowth, higher cellular projected area, and lower shape index for the cells cultured on the combined proteins conjugated fibers, indicating enhanced cellular spread on the scaffold. This preliminary study suggests that PCL nanoscaffolding conjugated with matrix proteins can support neuronal cell viability and neurite growth.

Coaxial nanofibers outperform uniaxial nanofibers for the loading and release of pyrroloquinoline quinone (PQQ) for biomedical applications

Pyrroloquinoline quinone (PQQ), present in breast milk and various foods, is highly recommended as an antioxidant, anti-inflammatory agent, and a cofactor in redox reactions in several biomedical fields. Moreover, PQQ has neuroprotective effects on nervous system disorders and immunosuppressive effects on different diseases. Herein, we report on the optimum fabrication of electrospun CS/PVA coaxial, core/shell, and uniaxial nanofibers. The morphological, elemental, and chemical structure of the fabricated nanofibers were investigated and discussed. PQQ, as a drug, was loaded on the uniaxial nanofibers and in the core of the coaxial nanofibers and the sustained and controlled release of PQQ was compared and discussed. The results revealed the privilege of the coaxial over the uniaxial nanofibers in the sustained release and reduction of the initial burst of PQQ. Remarkably, the results revealed a higher degree of swelling for CS/PVA hollow nanofibers compared to that of the uniaxial and the coaxial nanofibers. The coaxial nanofibers showed a lower release rate than the uniaxial nanofibers. Moreover, the CS/PVA coaxial nanofibers loaded with PQQ were found to enhance cell viability and proliferation. Therefore, the CS/PVA coaxial nanofibers loaded with PQQ assembly is considered a superior drug delivery system for PQQ release.

Ultrafast bone-like apatite formation on highly porous poly(l-lactic acid)-hydroxyapatite fibres

In order to provide a favourable environment for living bone formation, it is an essential condition to grow bone-like apatite layer at the interface between the tissue-implant and its surrounding tissues. Inspired by the chemical composition and the nano porous structure of natural bones, we developed an ultrafast and accessible route to accelerate effectively the formation of bone-like apatite on the surface of porous poly(l-lactic acid)-hydroxyapatite (PLLA-HA) composite fibres in 5 times simulated body fluid (5SBF). The key of the method lays in successful exposure of HA nanoparticles on the surface of PLLA fibres by acetone treatment of electrospun PLLA-HA nano/micro fibres. The recrystallization of PLLA chains uncovers more HA nanoparticles on the surface of every fibre which provide nucleation sites for calcium and phosphate ions. After only 2 h of immersing in 5SBF, a full layer of apatite completely covered on the surface of porous PLLA-HA fibres. The results indicate that HA nanoparticles on porous fibre surface can accelerate the kinetic deposition of apatite on fibre surface. Biological in vitro cell culture with human osteoblast-like cell for up to 7 days demonstrates that the incorporation of HA nanoparticles on the surface of porous PLLA fibrous membranes leads to significant enhance osteoblast adhesion and proliferation. The route can open avenues for development of fibrous PLLA biomaterials for hard tissue repair and substitution.

Nanofibers as drug-delivery systems for infection control in dentistry

INTRODUCTION

Due to the complexity of different oral infections, new anti-infective nanotechnological approaches have been emerging for dentistry in recent years. These strategies may contribute to antimicrobial molecules delivery, tissue regeneration, and oral health maintenance by acting in a more specific site and not being cytotoxic. In this context, nanofibers appear as versatile structures and might act both in the release of antimicrobial molecules and as a scaffold for new tissue formation.

AREAS COVERED

This review addresses the application of different nanofibers as new strategies for the delivery of antimicrobial molecules for dentistry. Here, we present the main polymers used to construct nanofibers, methods of production and mainly their antimicrobial activity against microorganisms commonly responsible for the usual dental infections. These biomaterials may be associated to restorative materials, prostheses, and mucoadhesive structures. Besides, nanofibers can be used for endodontic or periodontal therapy, or even on implant surfaces.

EXPERT OPINION

A wide variety of studies report the potential application of anti-infective nanofibers in the oral cavity. Although there are still several barriers between in vitro and in vivo studies, these new formulations appear as promising new therapies for dentistry.

Novel mineralized electrospun chitosan/PVA/TiO2 nanofibrous composites for potential biomedical applications: computational and experimental insights

Electrospun nanofibrous materials serve as potential solutions for several biomedical applications as they possess the ability of mimicking the extracellular matrix (ECM) of tissues. Herein, we report on the fabrication of novel nanostructured composite materials for potential use in biomedical applications that require a suitable environment for cellular viability. Anodized TiO2 nanotubes (TiO2 NTs) in powder form, with different concentrations, were incorporated as a filler material into a blend of chitosan (Cs) and polyvinyl alcohol (PVA) to synthesize composite polymeric electrospun nanofibrous materials. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), nanoindentation, Brunauer-Emmett-Teller (BET) analysis, and MTT assay for cell viability techniques were used to characterize the architectural, structural, mechanical, physical, and biological properties of the fabricated materials. Additionally, molecular dynamics (MD) modelling was performed to evaluate the mechanical properties of the polymeric PVA/chitosan matrix upon reinforcing the structure with TiO2 anatase nanotubes. The Young's modulus, shear and bulk moduli, Poisson's ratio, Lame's constants, and compressibility of these composites have been computed using the COMPASS molecular mechanics force fields. The MD simulations demonstrated that the inclusion of anatase TiO2 improves the mechanical properties of the composite, which is consistent with our experimental findings. The results revealed that the mineralized material improved the mechanical strength and the physical properties of the composite. Hence, the composite material has potential for use in biomedical applications.

Coaxial nanofiber scaffold with super-active platelet lysate to accelerate the repair of bone defects

To develop biocomposite materials with the local sustained-release function of biological factors to promote bone defect repair, coaxial electrospinning technology was performed to prepare a coaxial nanofiber scaffold with super-active platelet lysate (sPL), containing gelatin/PCL/PLLA. The nanofibers exhibited a uniform bead-free round morphology, observed by a scanning electron microscope (SEM), and the core/shell structure was confirmed by a transmission electron microscope (TEM). A mixture of polycaprolactone and sPL encapsulated by hydrophilic gelatin and hydrophobic l-polylactic acid can continuously release bioactive factors for up to 40 days. Encapsulation of sPL resulted in enhanced cell adhesion and proliferation, and sPL loading can increase the osteogenesis of osteoblasts. Besides, in vivo studies demonstrated that sPL-loaded biocomposites promoted the repair of skull defects in rats. Therefore, these results indicate that core–shell nanofibers loaded with sPL can add enormous potential to the clinical application of this scaffold in bone tissue engineering.

Coaxial electrospinning three-dimensional scaffold and its release various biological factors after filling the bone defect to induce adhesion and proliferation of osteoblasts on the nano scaffold.