In vitro study of a novel nanogold-collagen composite to enhance the mesenchymal stem cell behavior for vascular regeneration

A tissue-engineered neural interface with photothermal functionality

Neural interfaces are well-established as a tool to understand the behaviour of the nervous system via recording and stimulation of living neurons, as well as serving as neural prostheses. Conventional neural interfaces based on metals and carbon-based materials are generally optimised for high conductivity; however, a mechanical mismatch between the interface and the neural environment can significantly reduce long-term neuromodulation efficacy by causing an inflammatory response. This paper presents a soft composite material made of gelatin methacryloyl (GelMA) containing graphene oxide (GO) conjugated with gold nanorods (AuNRs). The soft hydrogel presents stiffness within the neural environment range of modulus below 5 kPa, while the AuNRs, when exposed to light in the near infrared range, provide a photothermal response that can be used to improve the spatial and temporal precision of neuromodulation. These favourable properties can be maintained at safer optical power levels when combined with electrical stimulation. In this paper we provide mechanical and biological characterization of the optical activity of the GO-AuNR composite hydrogel. The optical functionality of the material has been evaluated via photothermal stimulation of explanted rat retinal tissue. The outcomes achieved with this study encourage further investigation into optical and electrical costimulation parameters for a range of biomedical 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.

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.

The Use of Metallic Nanoparticles in Wound Healing: New Perspectives

Chronic wounds represent a challenge for the health area, as they directly impact patients' quality of life and represent a threat to public health and the global economy due to their high cost of treatment. Alternative strategies must be developed for cost-effective and targeted treatment. In this scenario, the emerging field of nanobiotechnology may provide an alternative platform to develop new therapeutic agents for the chronic wound healing process. This manuscript aims to demonstrate that the application of metallic nanoparticles (gold, silver, copper, and zinc oxide) opened a new chapter in the treatment of wounds, as they have different properties such as drug delivery, antimicrobial activity, and healing acceleration. Furthermore, metallic nanoparticles (NPs) produced through green synthesis ensure less toxicity in biological tissues, and greater safety of applicability, other than adding the effects of NPs with those of extracts.

Improved Delivery Performance of n-Butylidenephthalide-Polyethylene Glycol-Gold Nanoparticles Efficient for Enhanced Anti-Cancer Activity in Brain Tumor

n-butylidenephthalide (BP) has been verified as having the superior characteristic of cancer cell toxicity. Furthermore, gold (Au) nanoparticles are biocompatible materials, as well as effective carriers for delivering bio-active molecules for cancer therapeutics. In the present research, Au nanoparticles were first conjugated with polyethylene glycol (PEG), and then cross-linked with BP to obtain PEG-Au-BP nanodrugs. The physicochemical properties were characterized through ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS) to confirm the combination of PEG, Au, and BP. In addition, both the size and structure of Au nanoparticles were observed through scanning electron microscopy (SEM) and transmission electron microscopy (TEM), where the size of Au corresponded to the results of DLS assay. Through in vitro assessments, non-transformed BAEC and DBTRG human glioma cells were treated with PEG-Au-BP drugs to investigate the tumor-cell selective cytotoxicity, cell uptake efficiency, and mechanism of endocytic routes. According to the results of MTT assay, PEG-Au-BP was able to significantly inhibit DBTRG brain cancer cell proliferation. Additionally, cell uptake efficiency and potential cellular transportation in both BAEC and DBTRG cell lines were observed to be significantly higher at 2 and 24 h. Moreover, the mechanisms of endocytosis, clathrin-mediated endocytosis, and cell autophagy were explored and determined to be favorable routes for BAEC and DBTRG cells to absorb PEG-Au-BP nanodrugs. Next, the cell progression and apoptosis of DBTRG cells after PEG-Au-BP treatment was investigated by flow cytometry. The results show that PEG-Au-BP could remarkably regulate the DBTRG cell cycle at the Sub-G1 phase, as well as induce more apoptotic cells. The expression of apoptotic-related proteins in DBTRG cells was determined through Western blotting assay. After treatment with PEG-Au-BP, the apoptotic cascade proteins p21, Bax, and Act-caspase-3 were all significantly expressed in DBTRG brain cancer cells. Through in vivo assessments, the tissue morphology and particle distribution in a mouse model were examined after a retro-orbital sinus injection containing PEG-Au-BP nanodrugs. The results demonstrate tissue integrity in the brain (forebrain, cerebellum, and midbrain), heart, liver, spleen, lung, and kidney, as they did not show significant destruction due to PEG-Au-BP treatment. Simultaneously, the extended retention period for PEG-Au-BP nanodrugs was discovered, particularly in brain tissue. The above findings identify PEG-Au-BP as a potential nanodrug for brain cancer therapies.

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

Chitosan (Chi) is a natural polymer that has been demonstrated to have potential as a promoter of neural regeneration. In this study, Chi was prepared with various amounts (25, 50, and 100 ppm) of gold (Au) nanoparticles for use in in vitro and in vivo assessments. Each as-prepared material was first characterized by UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), and Dynamic Light Scattering (DLS). Through the in vitro experiments, Chi combined with 50 ppm of Au nanoparticles demonstrated better biocompatibility. The platelet activation, monocyte conversion, and intracellular ROS generation was remarkably decreased by Chi–Au 50 pm treatment. Furthermore, Chi–Au 50 ppm could facilitate colony formation and strengthen matrix metalloproteinase (MMP) activation in mesenchymal stem cells (MSCs). The lower expression of CD44 in Chi–Au 50 ppm treatment demonstrated that the nanocomposites could enhance the MSCs undergoing differentiation. Chi–Au 50 ppm was discovered to significantly induce the expression of GFAP, β-Tubulin, and nestin protein in MSCs for neural differentiation, which was verified by real-time PCR analysis and immunostaining assays. Additionally, a rat model involving subcutaneous implantation was used to evaluate the superior anti-inflammatory and endothelialization abilities of a Chi–Au 50 ppm treatment. Capsule formation and collagen deposition were decreased. The CD86 expression (M1 macrophage polarization) and leukocyte filtration (CD45) were remarkably reduced as well. In summary, a Chi polymer combined with 50 ppm of Au nanoparticles was proven to enhance the neural differentiation of MSCs and showed potential as a biosafe nanomaterial for neural tissue engineering.

Nanoarchitectonics for Ultrathin Gold Films Deposited on Collagen Fabric by High-Power Impulse Magnetron Sputtering

Gold nanoparticles conjugated with collagen molecules and fibers have been proven to improve structure strength, water and enzyme degradation resistance, cell attachment, cell proliferation, and skin wound healing. In this study, high-power impulse magnetron sputtering (HiPIMS) was used to deposit ultrathin gold films (UTGF) and discontinuous island structures on type I collagen substrates. A long turn-off time of duty cycle and low chamber temperature of HiPIMS maintained substrate morphology. Increasing the deposition time from 6 s to 30 s elevated the substrate surface coverage by UTGF up to 91.79%, as observed by a field emission scanning electron microscope. X-ray diffractometry analysis revealed signature low and wide peaks for Au (111). The important surface functional groups and signature peaks of collagen substrate remained unchanged according to Fourier transform infrared spectroscopy results. Multi-peak curve fitting of the Amide I spectrum revealed the non-changed protein secondary structure of type I collagen, which mainly consists of α-helix. Atomic force microscopy observation showed that the roughness average value shifted from 1.74 to 4.17 nm by increasing the deposition time from 13 s to 77 s. The uneven surface of collagen substrate made quantification of thin film thickness by AFM difficult. Instead, UTGF thickness was measured using simultaneously deposited glass specimens placed in an HiPIMS chamber with collagen substrates. Film thickness was 3.99 and 10.37 nm at deposition times of 13 and 77 s, respectively. X-ray photoelectron spectroscopy showed preserved substrate elements on the surface. Surface water contact angle measurement revealed the same temporary hydrophobic behavior before water absorption via exposed collagen substrates, regardless of deposition time. In conclusion, HiPIMS is an effective method to deposit UTGF on biomedical materials such as collagen without damaging valuable substrates. The composition of two materials could be further used for biomedical purposes with preserved functions of UTGF and collagen.

Evaluation of the Biocompatibility and Endothelial Differentiation Capacity of Mesenchymal Stem Cells by Polyethylene Glycol Nanogold Composites

Cardiovascular Diseases (CVDs) such as atherosclerosis, where inflammation occurs in the blood vessel wall, are one of the major causes of death worldwide. Mesenchymal Stem Cells (MSCs)-based treatment coupled with nanoparticles is considered to be a potential and promising therapeutic strategy for vascular regeneration. Thus, angiogenesis enhanced by nanoparticles is of critical concern. In this study, Polyethylene Glycol (PEG) incorporated with 43.5 ppm of gold (Au) nanoparticles was prepared for the evaluation of biological effects through in vitro and in vivo assessments. The physicochemical properties of PEG and PEG–Au nanocomposites were first characterized by UV-Vis spectrophotometry (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and Atomic Force Microscopy (AFMs). Furthermore, the reactive oxygen species scavenger ability as well as the hydrophilic property of the nanocomposites were also investigated. Afterwards, the biocompatibility and biological functions of the PEG–Au nanocomposites were evaluated through in vitro assays. The thin coating of PEG containing 43.5 ppm of Au nanoparticles induced the least platelet and monocyte activation. Additionally, the cell behavior of MSCs on PEG–Au 43.5 ppm coating demonstrated better cell proliferation, low ROS generation, and enhancement of cell migration, as well as protein expression of the endothelialization marker CD31, which is associated with angiogenesis capacity. Furthermore, anti-inflammatory and endothelial differentiation ability were both evaluated through in vivo assessments. The evidence demonstrated that PEG–Au 43.5 ppm implantation inhibited capsule formation and facilitated the expression of CD31 in rat models. TUNEL assay also indicated that PEG–Au nanocomposites would not induce significant cell apoptosis. The above results elucidate that the surface modification of PEG–Au nanomaterials may enable them to serve as efficient tools for vascular regeneration grafts.

Engineered Pullulan-Collagen-Gold Nano Composite Improves Mesenchymal Stem Cells Neural Differentiation and Inflammatory Regulation

Tissue repair engineering supported by nanoparticles and stem cells has been demonstrated as being an efficient strategy for promoting the healing potential during the regeneration of damaged tissues. In the current study, we prepared various nanomaterials including pure Pul, pure Col, Pul–Col, Pul–Au, Pul–Col–Au, and Col–Au to investigate their physicochemical properties, biocompatibility, biological functions, differentiation capacities, and anti-inflammatory abilities through in vitro and in vivo assessments. The physicochemical properties were characterized by SEM, DLS assay, contact angle measurements, UV-Vis spectra, FTIR spectra, SERS, and XPS analysis. The biocompatibility results demonstrated Pul–Col–Au enhanced cell viability, promoted anti-oxidative ability for MSCs and HSFs, and inhibited monocyte and platelet activation. Pul–Col–Au also induced the lowest cell apoptosis and facilitated the MMP activities. Moreover, we evaluated the efficacy of Pul–Col–Au in the enhancement of neuronal differentiation capacities for MSCs. Our animal models elucidated better biocompatibility, as well as the promotion of endothelialization after implanting Pul–Col–Au for a period of one month. The above evidence indicates the excellent biocompatibility, enhancement of neuronal differentiation, and anti-inflammatory capacities, suggesting that the combination of pullulan, collagen, and Au nanoparticles can be potential nanocomposites for neuronal repair, as well as skin tissue regeneration in any further clinical treatments.

Physical Gold Nanoparticle-Decorated Polyethylene Glycol-Hydroxyapatite Composites Guide Osteogenesis and Angiogenesis of Mesenchymal Stem Cells

In this study, polyethylene glycol (PEG) with hydroxyapatite (HA), with the incorporation of physical gold nanoparticles (AuNPs), was created and equipped through a surface coating technique in order to form PEG-HA-AuNP nanocomposites. The surface morphology and chemical composition were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), UV–Vis spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and contact angle assessment. The effects of PEG-HA-AuNP nanocomposites on the biocompatibility and biological activity of MC3T3-E1 osteoblast cells, endothelial cells (EC), macrophages (RAW 264.7), and human mesenchymal stem cells (MSCs), as well as the guiding of osteogenic differentiation, were estimated through the use of an in vitro assay. Moreover, the anti-inflammatory, biocompatibility, and endothelialization capacities were further assessed through in vivo evaluation. The PEG-HA-AuNP nanocomposites showed superior biological properties and biocompatibility capacity for cell behavior in both MC3T3-E1 cells and MSCs. These biological events surrounding the cells could be associated with the activation of adhesion, proliferation, migration, and differentiation processes on the PEG-HA-AuNP nanocomposites. Indeed, the induction of the osteogenic differentiation of MSCs by PEG-HA-AuNP nanocomposites and enhanced mineralization activity were also evidenced in this study. Moreover, from the in vivo assay, we further found that PEG-HA-AuNP nanocomposites not only facilitate the anti-immune response, as well as reducing CD86 expression, but also facilitate the endothelialization ability, as well as promoting CD31 expression, when implanted into rats subcutaneously for a period of 1 month. The current research illustrates the potential of PEG-HA-AuNP nanocomposites when used in combination with MSCs for the regeneration of bone tissue, with their nanotopography being employed as an applicable surface modification approach for the fabrication of biomaterials.

Fabrication of hyaluronic acid-gold nanoparticles with chitosan to modulate neural differentiation of mesenchymal stem cells

BACKGROUND

Chitosan (Chi) is a natural material which has been widely used in neural applications due to possessing better biocompatibility. In this research study, a novel of nanocomposites film based on Chi with hyaluronic acid (HA), combined with varying amounts of gold nanoparticles (AuNPs), was created resulting in pure Chi, Chi-HA, Chi-HA-AuNPs (25 ppm), and Chi-HA-AuNPs (50 ppm).

METHODS

This study focused on evaluating their effects on mesenchymal stem cell (MSC) viability, colony formation, and biocompatibility. The surface morphology and chemical position were characterized through UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), SEM, and contact-angle assessment.

RESULTS

When seeding MSCs on Chi-HA-AuNPs (50 ppm), the results showed high cell viability, biocompatibility, and the highest colony formation ability. Meanwhile, the evidence showed that Chi-HA-Au nanofilm was able to inhibit nestin and β-tubulin expression of MSCs, as well as inhibit the ability of neurogenic differentiation. Furthermore, the results of matrix metalloproteinase 2/9 (MMP2/9) expression in MSCs were also significantly higher in the Chi-HA-AuNP (50 ppm) group, guiding with angiogenesis and wound healing abilities. In addition, in our rat model, both capsule thickness and collagen deposition were the lowest in Chi-HA-AuNPs (50 ppm).

CONCLUSION

Thus, in view of the in vitro and in vivo results, Chi-HA-AuNPs (50 ppm) could not only maintain the greatest stemness properties and regulate the neurogenic differentiation ability of MSCs, but was able to also induce the least immune response. Herein, Chi-HA-Au 50 ppm nanofilm holds promise as a suitable material for nerve regeneration engineering.

Inflammatory Modulation of Polyethylene Glycol-AuNP for Regulation of the Neural Differentiation Capacity of Mesenchymal Stem Cells

A nanocomposite composed of polyethylene glycol (PEG) incorporated with various concentrations (~17.4, ~43.5, ~174 ppm) of gold nanoparticles (Au) was created to investigate its biocompatibility and biological performance in vitro and in vivo. First, surface topography and chemical composition was determined through UV-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), free radical scavenging ability, and water contact angle measurement. Additionally, the diameters of the PEG-Au nanocomposites were also evaluated through dynamic light scattering (DLS) assay. According to the results, PEG containing 43.5 ppm of Au demonstrated superior biocompatibility and biological properties for mesenchymal stem cells (MSCs), as well as superior osteogenic differentiation, adipocyte differentiation, and, particularly, neuronal differentiation. Indeed, PEG-Au 43.5 ppm induced better cell adhesion, proliferation and migration in MSCs. The higher expression of the SDF-1α/CXCR4 axis may be associated with MMPs activation and may have also promoted the differentiation capacity of MSCs. Moreover, it also prevented MSCs from apoptosis and inhibited macrophage and platelet activation, as well as reactive oxygen species (ROS) generation. Furthermore, the anti-inflammatory, biocompatibility, and endothelialization capacity of PEG-Au was measured in a rat model. After implanting the nanocomposites into rats subcutaneously for 4 weeks, PEG-Au 43.5 ppm was able to enhance the anti-immune response through inhibiting CD86 expression (M1 polarization), while also reducing leukocyte infiltration (CD45). Moreover, PEG-Au 43.5 ppm facilitated CD31 expression and anti-fibrosis ability. Above all, the PEG-Au nanocomposite was evidenced to strengthen the differentiation of MSCs into various cells, including fat, vessel, and bone tissue and, particularly, nerve cells. This research has elucidated that PEG combined with the appropriate amount of Au nanoparticles could become a potential biomaterial able to cooperate with MSCs for tissue regeneration engineering.

Delivery Capacity and Anticancer Ability of the Berberine-Loaded Gold Nanoparticles to Promote the Apoptosis Effect in Breast Cancer

Simple Summary

In this research, we aimed to evaluate the biological effects of physically gold nanoparticle-collagen nanocarrier incorporated with alkaloid berberine (Au-Col-BB) on non-transformed bovine aortic endothelial cells (BAEC) and Her-2 breast cancer cell lines through in vitro and in vivo assessments. Au-Col-BB showed better cytotoxicity, as well as significantly induced cell apoptosis in Her-2 cancer cells compared with normal cells (non-transformed BAEC). Further, Au-Col-BB also demonstrated better anti-cancer capacity for inhibiting cell growth in Her-2 tumor-bearing mice. In brief, we confirmed that the Au-Col-BB nanocarrier could be a potential nanodrug for increasing the efficiency of specific therapeutic effects in breast cancer disease.

Abstract

Gold nanoparticles (AuNPs) were fabricated with biocompatible collagen (Col) and then conjugated with berberine (BB), denoted as Au-Col-BB, to investigate the endocytic mechanisms in Her-2 breast cancer cell line and in bovine aortic endothelial cells (BAEC). Owing to the superior biocompatibility, tunable physicochemical properties, and potential functionalization with biomolecules, AuNPs have been well studied as carriers of biomolecules for diseases and cancer therapeutics. Composites of AuNPs with biopolymer, such as fibronectin or Col, have been revealed to increase cell proliferation, migration, and differentiation. BB is a natural compound with impressive health benefits, such as lowering blood sugar and reducing weight. In addition, BB can inhibit cell proliferation by modulating cell cycle progress and autophagy, and induce cell apoptosis in vivo and in vitro. In the current research, BB was conjugated on the Col-AuNP composite (“Au-Col”). The UV-Visible spectroscopy and infrared spectroscopy confirmed the conjugation of BB on Au-Col. The particle size of the Au-Col-BB conjugate was about 227 nm, determined by dynamic light scattering. Furthermore, Au-Col-BB was less cytotoxic to BAEC vs. Her-2 cell line in terms of MTT assay and cell cycle behavior. Au-Col-BB, compared to Au-Col, showed greater cell uptake capacity and potential cellular transportation by BAEC and Her-2 using the fluorescence-conjugated Au-Col-BB. In addition, the clathrin-mediated endocytosis and cell autophagy seemed to be the favorite endocytic mechanism for the internalization of Au-Col-BB by BAEC and Her-2. Au-Col-BB significantly inhibited cell migration in Her-2, but not in BAEC. Moreover, apoptotic cascade proteins, such as Bax and p21, were expressed in Her-2 after the treatment of Au-Col-BB. The tumor suppression was examined in a model of xenograft mice treated with Au-Col-BB nanovehicles. Results demonstrated that the tumor weight was remarkably reduced by the treatment of Au-Col-BB. Altogether, the promising findings of Au-Col-BB nanocarrier on Her-2 breast cancer cell line suggest that Au-Col-BB may be a good candidate of anticancer drug for the treatment of human breast cancer.

Nanogold-Carried Graphene Oxide: Anti-Inflammation and Increased Differentiation Capacity of Mesenchymal Stem Cells

Graphene-based nanocomposites such as graphene oxide (GO) and nanoparticle-decorated graphene with demonstrated excellent physicochemical properties have worthwhile applications in biomedicine and bioengineering such as tissue engineering. In this study, we fabricated gold nanoparticle-decorated GO (GO-Au) nanocomposites and characterized their physicochemical properties using UV-Vis absorption spectra, FTIR spectra, contact angle analyses, and free radical scavenging potential. Moreover, we investigated the potent applications of GO-Au nanocomposites on directing mesenchymal stem cells (MSCs) for tissue regeneration. We compared the efficacy of as-prepared GO-derived nanocomposites including GO, GO-Au, and GO-Au (×2) on the biocompatibility of MSCs, immune cell identification, anti-inflammatory effects, differentiation capacity, as well as animal immune compatibility. Our results showed that Au-deposited GO nanocomposites, especially GO-Au (×2), significantly exhibited increased cell viability of MSCs, had good anti-oxidative ability, sponged the immune response toward monocyte-macrophage transition, as well as inhibited the activity of platelets. Moreover, we also validated the superior efficacy of Au-deposited GO nanocomposites on the enhancement of cell motility and various MSCs-derived cell types of differentiation including neuron cells, adipocytes, osteocytes, and endothelial cells. Additionally, the lower induction of fibrotic formation, reduced M1 macrophage polarization, and higher induction of M2 macrophage, as well as promotion of the endothelialization, were also found in the Au-deposited GO nanocomposites implanted animal model. These results suggest that the Au-deposited GO nanocomposites have excellent immune compatibility and anti-inflammatory effects in vivo and in vitro. Altogether, our findings indicate that Au-decorated GO nanocomposites, especially GO-Au (×2), can be a potent nanocarrier for tissue engineering and an effective clinical strategy for anti-inflammation.

The Roles of Nanoparticles in Stem Cell-Based Therapy for Cardiovascular Disease

Cardiovascular disease (CVD) is currently one of the primary causes of mortality and morbidity worldwide. Nanoparticles (NPs) are playing increasingly important roles in regulating stem cell behavior because of their special features, including shape, size, aspect ratio, surface charge, and surface area. In terms of cardiac disease, NPs can facilitate gene delivery in stem cells, track the stem cells in vivo for long-term monitoring, and enhance retention after their transplantation. The advantages of applying NPs in peripheral vascular disease treatments include facilitating stem cell therapy, mimicking the extracellular matrix environment, and utilizing a safe non-viral gene delivery tool. However, the main limitation of NPs is toxicity, which is related to their size, shape, aspect ratio, and surface charge. Currently, there have been many animal models proving NPs’ potential in treating CVD, but no extensive applications of stem-cell therapy using NPs are available in clinical practice. In conclusion, NPs might have significant potential uses in clinical trials of CVD in the future, thereby meeting the changing needs of individual patients worldwide.

Nanogold Neuroprotection in Human Neural Stem Cells Against Amyloid-beta-induced Mitochondrial Dysfunction

Alzheimer's disease (AD) is a neuronal dementia with progressive memory loss. Amyloid-beta (Aβ) peptides has major effect in the neurodegenerative disorder, which are thought to promote mitochondrial dysfunction in AD brains. Anti-AD drugs acting upon the brain are generally difficult to develop, often cause serious side effects or lack therapeutic efficacy. Numerous studies have shown the beneficial therapeutic applications of gold nanoparticles (AuNPs), including for neuroprotective events and AD. The aim of this study is to understand how AuNPs could exert their neuroprotective role in AD, for which cell model have chosen human neural stem cells (hNSCs) as the experimental tool. We hypothesize AuNPs protect against Aβ-induced cellular impairment and mitochondrial dysfunction in hNSCs. Here, we show AuNPs increase the survival of hNSCs treated with Aβ via downregulation of caspase 3 and 9 activities. Moreover, AuNPs abrogated the Aβ-mediated decrease neuroprotective (CREB and Bcl-2) and mitochondrial (PGC1α, NRF-1 and Tfam) gene expressions in treated hNSCs. Importantly, co-treatment with AuNPs significantly rescued hNSCs from Aβ-mediated mitochondrial function and morphology. AuNPs also significantly normalizes the immunostaining of mitochondrial marker and mass in differentiated hNSCs with Aβ. The effects may be exerted by the AuNPs, as supported by its protective reversal of Aβ-induced cellular impairment and mitochondrial dysfunction in hNSCs. In fact, the results presented extend our understanding of the mechanisms through which AuNPs could exert their neuroprotective role in hNSCs treated with Aβ.

Functional engineered mesenchymal stem cells with fibronectin-gold composite coated catheters for vascular tissue regeneration

Vascularization of engineered tissues remains one of the key problems. Here, we described a novel approach to promote vascularization of engineered tissues using fibronectin (FN) incorporated gold nanoparticles (AuNP) coated onto catheters with mesenchymal stem cells (MSCs) for tissue engineering. We found that the FN-AuNP composite with 43.5 ppm of AuNP exhibited better biomechanical properties and thermal stability than pure FN. FN-AuNP composites promoted MSC proliferation and increased the biocompatibility. Mechanistically, vascular endothelial growth factor (VEGF) promoted MSC migration on FN-AuNP through the endothelial oxide synthase (eNOS)/metalloproteinase (MMP) signaling pathway. Vascular femoral artery tissues isolated from the implanted FN-AuNP-coated catheters with MSCs expressed substantial CD31 and alpha-smooth muscle actin (α-SMA), displayed higher antithrombotic activity, as well as better endothelialization ability than those coated with all other materials. These data suggested that the implantation of FN-AuNP-coated catheter with MSCs could be a novel strategy for vascular biomaterials applications.

Enhanced migration of murine fibroblast-like 3T3-L1 preadipocytes on type I collagen-coated dish is reversed by silibinin treatment

Migration of fibroblast-like preadipocytes is important for the development of adipose tissue, whereas excessive migration is often responsible for impaired adipose tissue related with obesity and fibrotic diseases. Type I collagen (collagen I) is the most abundant component of extracellular matrix and has been shown to regulate fibroblast migration in vitro, but its role in adipose tissue is not known. Silibinin is a bioactive natural flavonoid with antioxidant and antimetastasis activities. In this study, we found that type I collagen coating promoted the proliferation and migration of murine 3T3-L1 preadipocytes in a dose-dependent manner, implying that collagen I could be an extracellular signal. Regarding the mechanisms of collagen I-stimulated 3T3-L1 migration, we found that NF-κB p65 is activated, including the increased nuclear translocation of NF-κB p65 as well as the upregulation of NF-κB p65 phosphorylation and acetylation, accompanied by the increased expressions of proinflammatory factors and the generation of reactive oxygen species (ROS). Reduction of collagen I-enhanced migration of cells by treatment with silibinin was associated with suppression of NF-κB p65 activity and ROS generation, and negatively correlated with the increasing sirt1 expression. Taken together, the enhanced migration of 3T3-L1 cells induced on collagen I-coated dish is mediated by the activation of NF-κB p65 function and ROS generation that can be alleviated with silibinin by upregulation of sirt1, leading to the repression of NF-κB p65 function and ROS generation.

Characterization of Cell Scaffolds by Atomic Force Microscopy

This review reports on the use of the atomic force microscopy (AFM) in the investigation of cell scaffolds in recent years. It is shown how the technique is able to deliver information about the scaffold surface properties (e.g., topography), as well as about its mechanical behavior (Young's modulus, viscosity, and adhesion). In addition, this short review also points out the utilization of the atomic force microscope technique beyond its usual employment in order to investigate another type of basic questions related to materials physics, chemistry, and biology. The final section discusses in detail the novel uses that those alternative measuring modes can bring to this field in the future.

Remote Control and Modulation of Cellular Events by Plasmonic Gold Nanoparticles: Implications and Opportunities for Biomedical Applications

Compared to traditional hyperthermia methods, gold nanoparticles (Au NPs) successfully achieve site-specific incremental temperature in deep tissues. By virtue of near-infrared (NIR) laser-mediated photothermal treatment, Au NPs have been widely explored in clinical and preclinical applications, including cancer therapy and tissue engineering. In this issue of ACS Nano, Suzuki, Ciofani, and colleagues demonstrate how gold nanoshells can remotely activate striated muscle cells via inducing myotube contraction and modulating related gene expression by mild heat stimulation under NIR irradiation. This Perspective provides a brief overview of the current developments and future outlook for multifunctional platforms based on Au NPs for cancer treatment, tissue engineering, and regenerative medicine.

Biomedical Applications of Multifunctional Gold-Based Nanocomposites

Active application of gold nanoparticles for various diagnostic and therapeutic purposes started in recent decades due to the emergence of new data on their unique optical and physicochemical properties. In addition to colloidal gold conjugates, growth in the number of publications devoted to the synthesis and application of multifunctional nanocomposites has occurred in recent years. This review considers the application in biomedicine of multifunctional nanoparticles that can be produced in three different ways. The first method involves design of composite nanostructures with various components intended for either diagnostic or therapeutic functions. The second approach uses new bioconjugation techniques that allow functionalization of gold nanoparticles with various molecules, thus combining diagnostic and therapeutic functions in one medical procedure. Finally, the third method for production of multifunctional nanoparticles combines the first two approaches, in which a composite nanoparticle is additionally functionalized by molecules having different properties.

Prominent Vascularization Capacity of Mesenchymal Stem Cells in Collagen-Gold Nanocomposites

The ideal characteristics of surface modification on the vascular graft for clinical application would be with excellent hemocompatibility, endothelialization capacity, and antirestenosis ability. Here, Fourier transform infrared spectroscopy (FTIR), surface enhanced Raman spectroscopy (SERS), atomic force microscopy (AFM), contact angle (θ) measurement, and thermogravimetric analysis (TGA) were used to evaluate the chemical and mechanical properties of collagen-gold nanocomposites (collagen+Au) with 17.4, 43.5, and 174 ppm of Au and suggested that the collagen+Au with 43.5 ppm of Au had better biomechanical properties and thermal stability than pure collagen. Besides, stromal-derived factor-1α (SDF-1α) at 50 ng/mL promoted the migration of mesenchymal stem cells (MSCs) on collagen+Au material through the α5β3 integrin/endothelial oxide synthase (eNOS)/metalloproteinase (MMP) signaling pathway which can be abolished by the knockdown of vascular endothelial growth factor (VEGF). The potentiality of collagen+Au with MSCs for vascular regeneration was evaluated by our in vivo rat model system. Artery tissues isolated from an implanted collagen+Au-coated catheter with MSCs expressed substantial CD-31 and α-SMA, displayed higher antifibrotic ability, antithrombotic activity, as well as anti-inflammatory response than all other materials. Our results indicated that the implantation of collagen+Au-coated catheters with MSCs could be a promising strategy for vascular regeneration.

Collagen/gold nanoparticle nanocomposites: A potential skin wound healing biomaterial

In this study, nanocomposite collagen scaffolds incorporating gold nanoparticles (AuNPs) were prepared for wound healing applications. Initially, dose (<20 ppm) and size (>20 nm) of AuNPs that were not cytotoxic on HaCat keratinocytes and 3T3 fibroblasts were determined. Both collagen sponges and AuNP-incorporated nanocomposites (CS-Au) were cross-linked with glutaraldehyde (CS-X and CS-AuX). Incorporation of AuNPs into cross-linked scaffolds enhanced their stability against enzymatic degradation and increased the tensile strength. Hydrolytic degradation of CS-Au group was also less than CS after seven days. Upon confirming in vitro biocompatibility of the scaffolds with cytotoxicity assays, cell attachment and proliferation tests and the in vivo efficacy for healing of full-thickness skin wounds were investigated by applying CS-X, CS-AuX or a commercial product (Matriderm®) onto defect sites and covering with Ioban® drapes. Defects were covered only with drapes for untreated control group. The wound areas were examined with histopathological and biomechanical tests after 14 days of operation. CS-AuX group was superior to untreated control and Matriderm®; it suppressed the inflammation while significantly promoting granulation tissue formation. Inflammatory reaction against CS-AuX was milder than CS-X. Neovascularization was also higher in CS-AuX than other groups, though the result was not significant. Wound closure in CS-X (76%), CS-AuX (69%), and Matriderm® (65%) were better than untreated control (45%). CS-AuX group had the highest tensile strength (significantly higher than Matriderm®) and modulus (significantly higher than Matriderm® and CS-X), indicating a faster course of dermal healing. Further studies are also needed to investigate whether higher loading of AuNPs affects these results positively in a statistically meaningful manner. Overall, their contribution to the enhancement of degradation profiles and mechanical properties, their excellent in vitro biocompatibility, and tendency to accelerate wound healing are encouraging the use of AuNPs in collagen sponges as potent skin substitutes in the future.

Wet electrospun silk fibroin/gold nanoparticle 3D matrices for wound healing applications

The effectiveness of a silk fibroin/gold nanoparticle 3D nanofibrous matrix on a rat model of full-thickness dermal wound healing was investigated.

Europium-doped Gd2O3 nanotubes cause the necrosis of primary mouse bone marrow stromal cells through lysosome and mitochondrion damage

With the wide applications of europium-doped Gd2O3 nanoparticles (Gd2O3:Eu(3+) NPs) in biomedical fields, it will inevitably increase the chance of human exposure. It was reported that Gd2O3:Eu(3+) NPs could accumulate in bone. However, there have been few reports about the potential effect of Gd2O3:Eu(3+) NPs on bone marrow stromal cells (BMSCs). In this study, the Gd2O3:Eu(3+) nanotubes were prepared and characterized by powder X-ray diffraction (XRD), photoluminescence (PL) excitation and emission spectra, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The cytotoxicity of Gd2O3:Eu(3+) nanotubes on BMSCs and the associated mechanisms were further studied. The results indicated that they could be uptaken into BMSCs by an energy-dependent and macropinocytosis-mediated endocytosis process, and primarily localized in lysosome. Gd2O3:Eu(3+) nanotubes effectively inhibited the viability of BMSCs in concentration and time-dependent manners. A significant increase in the percentage of late apoptotic/necrotic cells, lactate dehydrogenase (LDH) leakage and the number of PI-stained cells was found after BMSCs were treated by 10, 20, and 40μg/mL of Gd2O3:Eu(3+) nanotubes for 12h. No obvious DNA ladders were detected, but a dispersed band was observed. The above results revealed that Gd2O3:Eu(3+) nanotubes could trigger cell death by necrosis instead of apoptosis. Two mechanisms were involved in Gd2O3:Eu(3+) nanotube-induced BMSCs necrosis: lysosomal rupture and release of cathepsins B; and the overproduction of reactive oxygen species (ROS) injury to the mitochondria and DNA. The study provides novel evidence to elucidate the toxicity mechanisms and may be beneficial to more rational applications of these nanomaterials in the future.

Recent advances in gold nanoparticle-based bioengineering applications

The recently developed gold nanoparticle-based bioengineering technologies for biosensors,in vitroandin vivobioimaging, drug delivery systems for improved therapeutics and tissue engineering are discussed.