Tailoring surface properties of carbon nanofibers via oxidation and its influence on dental pulp stem cell viability of PCL/CNF composites

An updated review and recent advancements in carbon-based bioactive coatings for dental implant applications

BACKGROUND

Surface coating of dental implants with a bioactive biomaterial is one of the distinguished approaches to improve the osseointegration potential, antibacterial properties, durability, and clinical success rate of dental implants. Carbon-based bioactive coatings, a unique class of biomaterial that possesses excellent mechanical properties, high chemical and thermal stability, osteoconductivity, corrosion resistance, and biocompatibility, have been utilized successfully for this purpose.

AIM

This review aims to present a comprehensive overview of the structure, properties, coating techniques, and application of the various carbon-based coatings for dental implant applicationswith a particular focuson Carbon-based nanomaterial (CNMs), which is an advanced class of biomaterials.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Available articles on carbon coatings for dental implants were reviewed using PubMed, Science Direct, and Google Scholar resources. Carbon-based coatings are non-cytotoxic, highly biocompatible, chemically inert, and osteoconductive, which allows the bone cells to come into close contact with the implant surface and prevents bacterial attachment and growth. Current research and advancements are now more focused on carbon-based nanomaterial (CNMs), as this emerging class of biomaterial possesses the advantage of both nanotechnology and carbon and aligns closely with ideal coating material characteristics. Carbon nanotubes, graphene, and its derivatives have received the most attention for dental implant coating. Various coating techniques are available for carbon-based materials, chosen according to substrate type, application requirements, and desired coating thickness. Vapor deposition technique, plasma spraying, laser deposition, and thermal spraying techniques are most commonly employed to coat the carbon structures on the implant surface. Longer duration trials and monitoring are required to ascertain the role of carbon-based bioactive coating for dental implant applications.

Surface-Oxidised Carbon Nanofibre-Based Nanofluids: Structural, Morphological, Stability and Thermal Properties

The reputation of nanofluids as a convenient heat transfer media has grown in recent years. The synthesis of nanofluids is often challenging, particularly carbon-based nanofluids, due to the rapid agglomeration of the nanoparticles and the instability of the nanofluids. In this regard, surface modification and surfactant addition are potential approaches to improve the physical and thermal properties of carbon-based nanofluids that have been studied and the structural, morphological, and thermal characteristics of surface-oxidised carbon nanofibre (CNF)-based nanofluids has been characterised. Commercial CNF was first subjected to three different acid treatments to introduce surface oxygen functional groups on the CNF surface. Following the physical and thermal characterisation of the three surface-oxidised CNFs (CNF-MA, CNF-MB, and CNF-MC), including Raman spectroscopy, Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM), the CNF-MB was selected as the best method to synthesise the surface-oxidised CNF-based nanofluid. A total of 40 mL of ultrapure water was used as a pure base fluid and mixed with the surface-oxidised CNF at a concentration range of 0.1-1.0 wt.%, with a fixed of 10 wt.% amount of polyvinylpyrrolidone (PVP). The thermal conductivity of CNF-based nanofluid was then characterised at different temperatures (6, 25, and 40 °C). Based on the results, surface oxidation via Method B significantly affected the extent of surface defects and effectively enhanced the group functionality on the CNF surface. Aside from the partially defective and rough surface of CNF-MB surfaces from the FESEM analysis, the presence of surface oxygen functional groups on the CNF wall was confirmed via the Raman analysis, TGA curve, and FTIR analysis. The visual sedimentation observation also showed that the surface-oxidised CNF particles remained dispersed in the nanofluid due to the weakened van der Waals interaction. The dispersion of CNF particles was improved by the presence of PVP, which further stabilised the CNF-based nanofluids. Ultimately, the thermal conductivity of the surface-oxidised CNF-based nanofluid with PVP was significantly improved with the highest enhancement percentage of 18.50, 16.84, and 19.83% at 6, 25, and 40 °C, respectively, at an optimum CNF concentration of 0.7 wt.%.

Recent Progress and Potential Biomedical Applications of Electrospun Nanofibers in Regeneration of Tissues and Organs

Electrospun techniques are promising and flexible technologies to fabricate ultrafine fiber/nanofiber materials from diverse materials with unique characteristics under optimum conditions. These fabricated fibers/nanofibers via electrospinning can be easily assembled into several shapes of three-dimensional (3D) structures and can be combined with other nanomaterials. Therefore, electrospun nanofibers, with their structural and functional advantages, have gained considerable attention from scientific communities as suitable candidates in biomedical fields, such as the regeneration of tissues and organs, where they can mimic the network structure of collagen fiber in its natural extracellular matrix(es). Due to these special features, electrospinning has been revolutionized as a successful technique to fabricate such nanomaterials from polymer media. Therefore, this review reports on recent progress in electrospun nanofibers and their applications in various biomedical fields, such as bone cell proliferation, nerve regeneration, and vascular tissue, and skin tissue, engineering. The functionalization of the fabricated electrospun nanofibers with different materials furnishes them with promising properties to enhance their employment in various fields of biomedical applications. Finally, we highlight the challenges and outlooks to improve and enhance the application of electrospun nanofibers in these applications.

Compositions and Structural Geometries of Scaffolds Used in the Regeneration of Cleft Palates: A Review of the Literature

Cleft palate (CP) is one of the most common birth defects, presenting a multitude of negative impacts on the health of the patient. It also leads to increased mortality at all stages of life, economic costs and psychosocial effects. The embryological development of CP has been outlined thanks to the advances made in recent years due to biomolecular successions. The etiology is broad and combines certain environmental and genetic factors. Currently, all surgical interventions work off the principle of restoring the area of the fissure and aesthetics of the patient, making use of bone substitutes. These can involve biological products, such as a demineralized bone matrix, as well as natural–synthetic polymers, and can be supplemented with nutrients or growth factors. For this reason, the following review analyzes different biomaterials in which nutrients or biomolecules have been added to improve the bioactive properties of the tissue construct to regenerate new bone, taking into account the greatest limitations of this approach, which are its use for bone substitutes for large areas exclusively and the lack of vascularity. Bone tissue engineering is a promising field, since it favors the development of porous synthetic substitutes with the ability to promote rapid and extensive vascularization within their structures for the regeneration of the CP area.