Preparation and characterization of novel chitosan/zeolite scaffolds for bone tissue engineering applications

Development of novel hybrid nanomaterials with potential application in bone/dental tissue engineering: design, fabrication and characterization enriched-SAPO-34/CS/PANI scaffold

Fe-Ca-SAPO-34/CS/PANI, a novel hybrid bio-composite scaffold with potential application in dental tissue engineering, was prepared by freeze drying technique. The scaffold was characterized using FT-IR and SEM methods. The effects of PANI on the physicochemical properties of the Fe-Ca-SAPO-34/CS scaffold were investigated, including changes in swelling ratio, mechanical behavior, density, porosity, biodegradation, and biomineralization. Compared to the Fe-Ca-SAPO-34/CS scaffold, adding PANI decreased the pore size, porosity, swelling ratio, and biodegradation, while increasing the mechanical strength and biomineralization. Cell viability, cytotoxicity, and adhesion of human dental pulp stem cells (hDPSCs) on the scaffolds were investigated by MTT assay and SEM. The Fe-Ca-SAPO-34/CS/PANI scaffold promoted hDPSC proliferation and osteogenic differentiation compared to the Fe-Ca-SAPO-34/CS scaffold. Alizarin red staining, alkaline phosphatase activity, and qRT-PCR results revealed that Fe-Ca-SAPO-34/CS/PANI triggered osteoblast/odontoblast differentiation in hDPSCs through the up-regulation of osteogenic marker genes BGLAP, RUNX2, and SPARC. The significance of this study lies in developing a novel scaffold that synergistically combines the beneficial properties of Fe-Ca-SAPO-34, chitosan, and PANI to create an optimized microenvironment for dental tissue regeneration. These findings highlight the potential of the Fe-Ca-SAPO-34/CS/PANI scaffold as a promising biomaterial for dental tissue engineering applications, paving the way for future research and clinical translation in regenerative dentistry.

Evaluation of bioactivity and biodegradability of a biomimetic soft tissue scaffold for clinical use: An in vitro study

Background

Autogenous soft-tissue graft is the gold-standard approach to augment oral soft tissues. However, tissue engineering is increasingly surveyed to overcome its substantial drawbacks, including the secondary site of operation, patient's pain and discomfort, limited tissue of donor site, and so on. Chitosan and gelatin have been utilized in this field over the years due to their great biological virtues. Zeolite, another remarkable candidate for tissue engineering, possesses outstanding biological and mechanical properties, thanks to its nanostructure. Therefore, this study aimed to investigate the biodegradability and DNA content of seeded human gingival fibroblasts on a New Chitosan-Gelatin-Zeolite Scaffold for the perspective of oral and mucosal soft tissue augmentation.

Materials and Methods

DNA contents of the human gingival fibroblast cell line (HGF.1) seeded on the chitosan-gelatin (CG) and CGZ scaffolds were evaluated by propidium iodide staining on days 1, 5, and 8. Scaffolds' biodegradations were investigated on days 1, 7, 14, 28, 42, and 60.

Results

Although both scaffolds provided appropriate substrates for HGF.1 growth, significantly higher DNA contents were recorded for the CGZ scaffold. Among experimental groups, the highest mean value was recorded in the CGZ on day 8. CGZ showed a significantly lower biodegradation percentage at all time points.

Conclusions

The incorporation of zeolite into the CG scaffold at a ratio of 1:10 improved the cell proliferation and stability of the composite scaffold. CGZ scaffold may offer a promising alternative to soft-tissue grafts due to its suitable biological features.

Zeolites as Ingredients of Medicinal Products

Development of new medicinal products for particular therapeutic treatment or for better manipulations with better quality and less side effects are possible as a result of advanced inorganic and organic materials application, among which zeolites, due to their properties and versatility, have been gaining attention. This paper is an overview of the development in the use of zeolite materials and their composites and modifications as medicinal products for several purposes such as active agents, carriers, for topical treatments, oral formulations, anticancer, the composition of theragnostic systems, vaccines, parenteral dosage forms, tissue engineering, etc. The objective of this review is to explore the main properties of zeolites and associate them with their drug interaction, mainly addressing the advances and studies related to the use of zeolites for different types of treatments due to their zeolite characteristics such as molecule storage capacity, physical and chemical stability, cation exchange capacity, and possibility of functionalization. The use of computational tools to predict the drug-zeolite interaction is also explored. As conclusion was possible to realize the possibilities and versatility of zeolite applications as being able to act in several aspects of medicinal products.

Chitosan - zeolite scaffold as a potential biomaterial in the controlled release of drugs for osteoporosis

Chitosan scaffolds are a potential material in many biomedical applications. A particularly interesting application is their use in bone tissue engineering. Because of their biocompatibility and nontoxicity, they are an ideal material for this application. What is missing from chitosan scaffolds is controlled drug release. They can obtain this property by adding drug carriers. In this work, chitosan‑calcium zeolite scaffolds were prepared and used in the controlled release of the drug for osteoporosis - risedronate. Their properties have been compared with those of the popular chitosan-hydroxyapatite scaffold. The zeolite was evenly distributed throughout the scaffold. More drug was retained on the scaffold with the addition of zeolite compared to that with the hydroxyapatite. The new scaffolds have proven to be able to retain the drug and slowly release it in small doses. The results obtained are promising and show great potential for this material in bone tissue engineering.

Zeolites: A series of promising biomaterials in bone tissue engineering

As an important worldwide medical issue, bone defect exhibits a variety of physical and psychological consequences on sufferers. Some features of clinical treatments including bone grafting and limb shortening are not satisfactory. Recently, bone tissue engineering has been considered as the most effective approach to dealing with the issue of bone deformities. Meanwhile, a variety of biomaterials have been rationally designed and created for the bone regeneration and tissue repairing. Among all these admirable biomaterials for bone remodeling, zeolite-based materials can serve as efficient scaffold candidates with excellent osteo-inductivity. In addition, the porous nature and high biocompatibility of zeolites endow them with the ability as ideal substrates for cell adhesion and proliferation. More importantly, zeolites are investigated as potential coating materials for implants because they have been proven to increase osteo-conductivity and aid in local elastic modeling. Last but not least, zeolites can also be used to treat bone disorders and act as dietary supplements during the practical applications. Accordingly, numerous benefits of zeolite prompt us to summarize their recent biomedical progress including but not limited to the distinguishing characteristics, broad classifications, as well as promising usages in bone tissue engineering.

Polyelectrolyte Multilayers Composed of Polyethyleneimine-Grafted Chitosan and Polyacrylic Acid for Controlled-Drug-Delivery Applications

In this work, polyethyleneimine (PEI)-grafted chitosan (Chi-g-PEI) was prepared for the fabrication of layer-by-layer (LBL) films for use in sustained-drug-delivery applications. Chi-g-PEI and polyacrylic acid (PAA) multilayer films were formed using the LBL technique. Methylene blue (MB) was used as a model drug for the investigation of loading and release capabilities of the LBL films. Characterizations of the synthesized copolymer were performed using Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance spectroscopy (NMR), Thermogravimetric analysis (TGA), and X-ray Powder Diffraction (XRD) techniques, and the thickness of the LBL films was measured using Atomic force microscopy (AFM). The drug-loading and -release behaviors of the LBL films were assessed using a UV–visible spectrophotometer. The results showed that the loading capacity and release rate of MB were affected by ionic strength and pH. In addition, it was demonstrated that PEI-grafted chitosan is a good candidate for the assembling of LBL films for drug-delivery applications.

Anti-Reflective Zeolite Coating for Implantable Bioelectronic Devices

Since sunlight is one of the most easily available and clean energy supplies, solar cell development and the improvement of its conversion efficiency represent a highly interesting topic. Superficial light reflection is one of the limiting factors of the photovoltaic cells (PV) efficiency. To this end, interfacial layer with anti-reflective properties reduces this phenomenon, improving the energy potentially available for transduction. Nanoporous materials, because of the correlation between the refractive index and the porosity, allow low reflection, improving light transmission through the coating. In this work, anti-reflective coatings (ARCs) deposited on commercial PV cells, which were fabricated using two different Linde Type A (LTA) zeolites (type 3A and 4A), have been investigated. The proposed technique allows an easier deposition of a zeolite-based mixture, avoiding the use of chemicals and elevated temperature calcination processes. Results using radiation in the range 470–610 nm evidenced substantial enhancement of the fill factor, with maximum achieved values of over 40%. At 590 and 610 nm, which are the most interesting bands for implantable devices, FF is improved, with a maximum of 22% and 10%, respectively. ARCs differences are mostly related to the morphology of the zeolite powder used, which resulted in thicker and rougher coatings using zeolite 3A. The proposed approach allows a simple and reliable deposition technique, which can be of interest for implantable medical devices.

Generation of Mesenchymal Cell Lines Derived from Aged Donors

Background: Mesenchymal stromal cells (MSCs) have the capacity for self-renewal and multi-differentiation, and for this reason they are considered a potential cellular source in regenerative medicine of cartilage and bone. However, research on this field is impaired by the predisposition of primary MSCs to senescence during culture expansion. Therefore, the aim of this study was to generate and characterize immortalized MSC (iMSC) lines from aged donors. Methods: Primary MSCs were immortalized by transduction of simian virus 40 large T antigen (SV40LT) and human telomerase reverse transcriptase (hTERT). Proliferation, senescence, phenotype and multi-differentiation potential of the resulting iMSC lines were analyzed. Results: MSCs proliferate faster than primary MSCs, overcome senescence and are phenotypically similar to primary MSCs. Nevertheless, their multi-differentiation potential is unbalanced towards the osteogenic lineage. There are no clear differences between osteoarthritis (OA) and non-OA iMSCs in terms of proliferation, senescence, phenotype or differentiation potential. Conclusions: Primary MSCs obtained from elderly patients can be immortalized by transduction of SV40LT and hTERT. The high osteogenic potential of iMSCs converts them into an excellent cellular source to take part in in vitro models to study bone tissue engineering.

Design and fabrication of M-SAPO-34/chitosan scaffolds and evaluation of their effects on dental tissue engineering

This research aimed to design innovative therapeutic bio-composites that enhance odontogenic and osteogenic differentiation of human dental pulp-derived mesenchymal stem cells (h-DPSCs) in-vitro regeneration. Herein, we report the fabrication of scaffolds containing chitosan, Ca-SAPO-34 monometallic and/or Fe-Ca-SAPO-34 bimetallic nanoparticles by freeze-drying technique. The scaffolds and nanoparticles were characterized using ICP-AES, FT-IR, XRD, TGA, TEM, BET, SEM, and EDS methods. The effects of SAPO-34 and nanoparticles were investigated by changes on the physicochemical properties of scaffolds including swelling ratio, density, porosity, bio-degradation, mechanical behavior, and biomineralization. Cell viability, cell adhesion and cytotoxicity of Ca-SAPO-34/CS and Fe-Ca-SAPO-34 scaffolds were investigated by MTT assay and SEM on h-DPSCs which revealed cell proliferation no toxicity on scaffolds. Cell tests demonstrated that Ca-SAPO-34/CS scaffold clearly displayed a positive effect on differentiation of hDPSCs into osteogenic/odontogenic cells and moderate effect on cell proliferation. Moreover, the incorporation of Fe₂O₃ to Ca-SAPO-34/CS scaffold promoted the proliferation of hDPSCs and osteogenic differentiation. Alizarin red, Alkaline phosphatase and QRT-PCR results showed that Fe-Ca-loaded SAPO-34/CS can lead to osteoblast/odontoblast differentiation in DPSCs through the up-regulation of related genes, thus indicating that Fe-Ca-SAPO-34/CS has remarkable prospects as a biomaterial for hard tissue engineering.

An in vitro evaluation of zinc silicate fortified chitosan scaffolds for bone tissue engineering

Tissue engineering aims at replacement, repair, and regeneration of tissues by a combination of scaffolds, growth factors, and cells. In this study, we report the synthesis of biodegradable composite scaffolds fortified with mesoporous zinc silicate (mZS) and assessment of in vitro properties for bone tissue engineering (BTE) applications. The scaffolds consisted of chitosan (CS) incorporated with mZS at 0.1, 0.2, 0.3, and 0.5 wt%. The bio-composite scaffolds were visualized using Field Emission Scanning Electron Microscopy (FE-SEM). The incorporation of mZS was confirmed using Energy dispersive x-ray (EDS) analysis. Biomineralization studies were conducted in simulated body fluid (SBF) and indicated bioactivity of fabricated scaffolds. The scaffolds also displayed antibacterial action against Staphylococcus aureus. Cellular attachment within the scaffold network established biocompatibility of the material. Incorporation of mZS within the chitosan scaffolds matrix improved properties such as porosity, degradation rate, and biomineralization. Therefore, fabricated scaffolds exhibit exceptional features and have the potential to serve as an implant for BTE applications.

Zeolite in tissue engineering: Opportunities and challenges

Tissue engineering and regenerative medicine follow a multidisciplinary attitude to the expansion and application of new materials for the treatment of different tissue defects. Typically, proper tissue regeneration is accomplished through concurrent biocompatibility and positive cellular activity. This can be resulted by the smart selection of platforms among bewildering arrays of structural possibilities with various porosity properties (ie, pore size, pore connectivity, etc). Among diverse porous structures, zeolite is known as a microporous tectosilicate that can potentially provide a biological microenvironment in tissue engineering applications. In addition, zeolite has been particularly appeared promising in wound dressing and bone‐ and tooth‐oriented scaffolds. The wide range of composition and hierarchical pore structure renders the zeolitic materials a unique character, particularly, for tissue engineering purposes. Despite such unique features, research on zeolitic platforms for tissue engineering has not been classically presented. In this review, we overview, classify, and categorize zeolitic platforms employed in biological and tissue engineering applications.

Usefulness of Mesenchymal Cell Lines for Bone and Cartilage Regeneration Research

The unavailability of sufficient numbers of human primary cells is a major roadblock for in vitro repair of bone and/or cartilage, and for performing disease modelling experiments. Immortalized mesenchymal stromal cells (iMSCs) may be employed as a research tool for avoiding these problems. The purpose of this review was to revise the available literature on the characteristics of the iMSC lines, paying special attention to the maintenance of the phenotype of the primary cells from which they were derived, and whether they are effectively useful for in vitro disease modeling and cell therapy purposes. This review was performed by searching on Web of Science, Scopus, and PubMed databases from 1 January 2015 to 30 September 2019. The keywords used were ALL = (mesenchymal AND ("cell line" OR immortal*) AND (cartilage OR chondrogenesis OR bone OR osteogenesis) AND human). Only original research studies in which a human iMSC line was employed for osteogenesis or chondrogenesis experiments were included. After describing the success of the immortalization protocol, we focused on the iMSCs maintenance of the parental phenotype and multipotency. According to the literature revised, it seems that the maintenance of these characteristics is not guaranteed by immortalization, and that careful selection and validation of clones with particular characteristics is necessary for taking advantage of the full potential of iMSC to be employed in bone and cartilage-related research.