Neural Differentiation Potential of Mesenchymal Stem Cells Enhanced by Biocompatible Chitosan-Gold Nanocomposites

Chitosan alchemy: transforming tissue engineering and wound healing

Chitosan, a biopolymer acquired from chitin, has emerged as a versatile and favorable material in the domain of tissue engineering and wound healing. Its biocompatibility, biodegradability, and antimicrobial characteristics make it a suitable candidate for these applications. In tissue engineering, chitosan-based formulations have garnered substantial attention as they have the ability to mimic the extracellular matrix, furnishing an optimal microenvironment for cell adhesion, proliferation, and differentiation. In the realm of wound healing, chitosan-based dressings have revealed exceptional characteristics. They maintain a moist wound environment, expedite wound closure, and prevent infections. These formulations provide controlled release mechanisms, assuring sustained delivery of bioactive molecules to the wound area. Chitosan's immunomodulatory properties have also been investigated to govern the inflammatory reaction during wound healing, fostering a balanced healing procedure. In summary, recent progress in chitosan-based formulations portrays a substantial stride in tissue engineering and wound healing. These innovative approaches hold great promise for enhancing patient outcomes, diminishing healing times, and minimizing complications in clinical settings. Continued research and development in this field are anticipated to lead to even more sophisticated chitosan-based formulations for tissue repair and wound management. The integration of chitosan with emergent technologies emphasizes its potential as a cornerstone in the future of regenerative medicine and wound care. Initially, this review provides an outline of sources and unique properties of chitosan, followed by recent signs of progress in chitosan-based formulations for tissue engineering and wound healing, underscoring their potential and innovative strategies.

Biological Performance of Primary Dental Pulp Stem Cells Treated with Gold Nanoparticles

Gold nanoparticles (AuNPs) are one of the most stable nanoparticles that have been prevalently used as examples for biological and biomedical applications. Herein, we evaluate the effect of AuNPs on the biological processes of dental pulp stem cells derived from exfoliated deciduous teeth (SHED). Two different shapes of PEGylated AuNPs, rods (AuNR-PEG) and spheres (AuNS-PEG), were prepared and characterized. SHED cells were treated with different concentrations of AuNR-PEG and AuNS-PEG to determine their effect on the stemness profile of stem cells (SCs), proliferation, cytotoxicity, cellular uptake, and reactive oxygen species (ROS), for cells cultured in media containing-fetal bovine serum (FBS) and serum-free media (SFM). Our results showed that both nanoparticle shapes maintained the expression profile of MSC surface markers. Moreover, AuNS-PEG showed a stimulatory effect on the proliferation rate and lower toxicity on SHED, compared to AuNR-PEG. Higher concentrations of 0.5-0.125 nM of AuNR-PEG have been demonstrated to cause more toxicity in cells. Additionally, cells treated with AuNPs and cultured in FBS showed a higher proliferative rate and lower toxicity when compared to the SFM. For cellular uptake, both AuNS-PEG and AuNR-PEG were uptaken by treated cells efficiently. However, cells cultured in SFM media showed a higher percentage of cellular uptake. For ROS, AuNR-PEG showed a significant reduction in ROS at lower concentrations (<0.03 nM), while AuNS-PEG did not show any significant difference compared to the control untreated cells. Thus, our results give evidence about the optimum concentration and shape of AuNPs that can be used for the differentiation of stem cells into specific cell lineages in tissue engineering and regenerative medicine.

Interactions of Cells and Biomaterials for Nerve Tissue Engineering: Polymers and Fabrication

Neural injuries affect millions globally, significantly impacting their quality of life. The inability of these injuries to heal, limited ability to regenerate, and the lack of available treatments make regenerative medicine and tissue engineering a promising field of research for developing methods for nerve repair. This review evaluates the use of natural and synthetic polymers, and the fabrication methods applied that influence a cell's behavior. Methods include cross-linking hydrogels, incorporation of nanoparticles, and 3D printing with and without live cells. The endogenous cells within the injured area and any exogenous cells seeded on the polymer construct play a vital role in regulating healthy neural activity. This review evaluates the body's local and systemic reactions to the implanted materials. Although numerous variables are involved, many of these materials and methods have exhibited the potential to provide a biomaterial environment that promotes biocompatibility and the regeneration of a physical and functional nerve. Future studies may evaluate advanced methods for modifying material properties and characterizing the tissue-biomaterial interface for clinical applications.

Assessment of the potential cerebellar toxicity of gold nanoparticles on the structure and function of adult male albino rats

BACKGROUND

The regular use of gold nanoparticles (Au-NPs) may increase the likelihood of human exposure to these nanoparticles (NPs) and raises concerns about toxicity.

AIM

This study investigated the short-term impact of exposure to Au-NPs on inducing cerebellar pathology in rats, and whether the dose or duration of exposure was more important.

METHODOLOGY

The study used two concentrations of Au-NPs (25 and 50 particles per million) and 18 rats were randomly assigned to three groups. Assessments of the animals were done via behavioral, gene expression, histological, and immunohistochemistry analyses.

RESULTS

Both concentrations of Au-NPs caused cerebellar pathology, as assessed through the investigation test battery. The Au-NPs50 group displayed more injury and decreased mobility compared with the control and the Au-NPs25 group. The Au-NPs25 group showed an increase in supported rearing and significant up-regulation of the Rgc32 gene compared with the control. The Trkb gene was insignificantly up-regulated in both Au-NPs groups compared with the control.

CONCLUSION

The study indicates that exposure to Au-NPs can cause cerebellar pathology in rats and that the toxicity is more dependent on dose than the duration of exposure. These findings have significant implications for the safe use of Au-NPs in various applications.

Therapeutic Applications of Mesenchymal Stem Cell Loaded with Gold Nanoparticles for Regenerative Medicine

In the present study, the various concentrations of AuNP (1.25, 2.5, 5, 10 ppm) were prepared to investigate the biocompatibility, biological performances and cell uptake efficiency via Wharton's jelly mesenchymal stem cells and rat model. The pure AuNP, AuNP combined with Col (AuNP-Col) and FITC conjugated AuNP-Col (AuNP-Col-FITC) were characterized by Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and Dynamic Light Scattering (DLS) assays. For in vitro examinations, we explored whether the Wharton's jelly MSCs had better viability, higher CXCR4 expression, greater migration distance and lower apoptotic-related proteins expression with AuNP 1.25 and 2.5 ppm treatments. Furthermore, we considered whether the treatments of 1.25 and 2.5 ppm AuNP could induce the CXCR4 knocked down Wharton's jelly MSCs to express CXCR4 and reduce the expression level of apoptotic proteins. We also treated the Wharton's jelly MSCs with AuNP-Col to investigate the intracellular uptake mechanisms. The evidence demonstrated the cells uptake AuNP-Col through clathrin-mediated endocytosis and the vacuolar-type H⁺-ATPase pathway with good stability inside the cells to avoid lysosomal degradation as well as better uptake efficiency. Additionally, the results from in vivo examinations elucidated the 2.5 ppm of AuNP attenuated foreign body responses and had better retention efficacy with tissue integrity in animal model. In conclusion, the evidence demonstrates that AuNP shows promise as a biosafe nanodrug delivery system for development of regenerative medicine coupled with Wharton's jelly MSCs.

Nanotherapeutic and Stem Cell Therapeutic Strategies in Neurodegenerative Diseases: A Promising Therapeutic Approach

Neurodegeneration is characterized by progressive, disabling, and incurable neurological disorders with the massive loss of specific neurons. As one of the most promising potential therapeutic strategies for neurodegenerative diseases, stem cell therapy exerts beneficial effects through different mechanisms, such as direct replacement of damaged or lost cells, secretion of neurotrophic and growth factors, decreased neuroinflammation, and activation of endogenous stem cells. However, poor survival and differentiation rates of transplanted stem cells, insufficient homing ability, and difficulty tracking after transplantation limit their further clinical use. The rapid development of nanotechnology provides many promising nanomaterials for biomedical applications, which already have many applications in neurodegenerative disease treatment and seem to be able to compensate for some of the deficiencies in stem cell therapy, such as transport of stem cells/genes/drugs, regulating stem cell differentiation, and real-time tracking in stem cell therapy. Therefore, nanotherapeutic strategies combined with stem cell therapy is a promising therapeutic approach to treating neurodegenerative diseases. The present review systematically summarizes recent advances in stem cell therapeutics and nanotherapeutic strategies and highlights how they can be combined to improve therapeutic efficacy for the treatment of neurodegenerative diseases.

Favorable Biological Performance Regarding the Interaction between Gold Nanoparticles and Mesenchymal Stem Cells

Gold nanoparticles (AuNPs) are well known to interact with cells, leading to different cell behaviors such as cell proliferation and differentiation capacity. Biocompatibility and biological functions enhanced by nanomedicine are the most concerning factors in clinical approaches. In the present research, AuNP solutions were prepared at concentrations of 1.25, 2.5, 5 and 10 ppm for biocompatibility investigations. Ultraviolet-visible spectroscopy was applied to identify the presence of AuNPs under the various concentrations. Dynamic Light Scattering assay was used for the characterization of the size of the AuNPs. The shape of the AuNPs was observed through a Scanning Electron Microscope. Afterward, the mesenchymal stem cells (MSCs) were treated with a differentiation concentration of AuNP solutions in order to measure the biocompatibility of the nanoparticles. Our results demonstrate that AuNPs at 1.25 and 2.5 ppm could significantly enhance MSC proliferation, decrease reactive oxygen species (ROS) generation and attenuate platelet/monocyte activation. Furthermore, the MSC morphology was observed in the presence of filopodia and lamellipodia while being incubated with 1.25 and 2.5 ppm AuNPs, indicating that the adhesion ability was enhanced by the nanoparticles. The expression of matrix metalloproteinase (MMP-2/9) in MSCs was found to be more highly expressed under 1.25 and 2.5 ppm AuNP treatment, relating to better cell migrating ability. Additionally, the cell apoptosis of MSCs investigated with Annexin-V/PI double staining assay and the Fluorescence Activated Cell Sorting (FACS) method demonstrated the lower population of apoptotic cells in 1.25 and 2.5 ppm AuNP treatments, as compared to high concentrations of AuNPs. Additionally, results from a Western blotting assay explored the possibility that the anti-apoptotic proteins Cyclin-D1 and Bcl-2 were remarkably expressed. Meanwhile, real-time PCR analysis demonstrated that the 1.25 and 2.5 ppm AuNP solutions induced a lower expression of inflammatory cytokines (TNF-α, IL-1β, IFN-γ, IL-6 and IL-8). According to the tests performed on an animal model, AuNP 1.25 and 2.5 ppm treatments exhibited the better biocompatibility performance, including anti-inflammation and endothelialization. In brief, 1.25 and 2.5 ppm of AuNP solution was verified to strengthen the biological functions of MSCs, and thus suggests that AuNPs become the biocompatibility nanomedicine for regeneration research.