Polymeric nanobiocomposites for biomedical applications

Three-Dimensional Printed Poly (Lactic-co-Glycolic Acid)-Magnesium Composite Scaffolds for the Promotion of Osteogenesis Through Immunoregulation

Scaffolds play an important role in bone tissue engineering. The ideal engineered scaffold needs to be biocompatible, bioactive, and able to regulate immune cells to enhance bone regeneration. In this study, magnesium (Mg)-contained poly(lactic-co-glycolic acid) (PLGA) scaffolds (hereinafter, referred to as PLGA-2Mg) were fabricated by 3-dimensional printing using a mixture of PLGA and MgSO 4 powder. Poly(lactic-co-glycolic acid) scaffolds (hereinafter, referred to as PLGA) were also fabricated by 3-dimensional printing and were used as control. The biocompatibility, immunoregulatory ability, and osteogenic properties of PLGA-2Mg were analyzed and compared with those of PLGA. The results indicate that the incorporation of Mg increased the Young modulus and surface roughness of the scaffold, but did not affect its degradation. The PLGA-2Mg further promoted the adhesion and proliferation of MC3T3-E1 cells compared with PLGA, which indicates its improved biocompatibility and bioactivity. In addition, PLGA-2Mg inhibited the polarization of RAW 264.7 cells toward the M1 phenotype by down-regulating the IL-1β , IL-6 , and iNOs gene expression when challenged with lipopolysaccharide stimulation. In contrast, it promoted the polarization of RAW 264.7 cells toward the M2 phenotype by up-regulating the TGF-β , IL-10 , and Arg-1 gene expression without lipopolysaccharide stimulation. Finally, MC3T3-E1 cells were cocultured with RAW 264.7 cells and scaffolds using a transwell system. It was found that the expression level of osteogenic-related genes ( ALP , COL-1 , BMP2 , and BSP ) was significantly upregulated in the PLGA-2Mg group compared with that in the PLGA group. Consequently, PLGA-2Mg with increased biocompatibility and bioactivity can promote osteogenesis through immunoregulation and has the potential to be used as a novel scaffold in bone tissue engineering.

Polymer/Layered Clay/Polyurethane Nanocomposites: P3HB Hybrid Nanobiocomposites-Preparation and Properties Evaluation

This paper presents an attempt to improve the properties of poly(3-hydroxybutyrate) (P3HB) using linear aliphatic polyurethane (PU400) and organomodified montmorillonite (MMT)-(Cloisite^®30B). The nanostructure of hybrid nanobiocomposites produced by extrusion was analyzed by X-ray diffraction and transmission electron microscopy, and the morphology was analyzed by scanning electron microscopy. In addition, selected mechanical properties and thermal properties were studied by thermogravimetric analysis, TGA, and differential scanning calorimetry, DSC. The interactions of the composite ingredients were indicated by FT IR spectroscopy. The effect of the amount of nanofiller on the properties of prepared hybrid nanobiocomposites was noted. Moreover, the non-equilibrium and equilibrium thermal parameters of nanobiocomposites were established based on their thermal history. Based on equilibrium parameters (i.e., the heat of fusion for the fully crystalline materials and the change in the heat capacity at the glass transition temperature for the fully amorphous nanobiocomposites), the degree of crystallinity and the mobile and rigid amorphous fractions were estimated. The addition of Cloisite^®30B and aliphatic polyurethane to the P3HB matrix caused a decrease in the degree of crystallinity in reference to the unfilled P3HB. Simultaneously, an increase in the amorphous phase contents was noted. A rigid amorphous fraction was also denoted. Thermogravimetric analysis of the nanocomposites was also carried out and showed that the thermal stability of all nanocomposites was higher than that of the unfilled P3HB. An additional 1% mass of nanofiller increased the degradation temperature of the nanocomposites by about 30 °C in reference to the unfilled P3HB. Moreover, it was found that obtained hybrid nanobiocomposites containing 10 wt.% of aliphatic polyurethane (PU400) and the smallest amount of nanofiller (1 wt.% of Cloisite^®30B) showed the best mechanical properties. We observed a desirable decrease in hardness of 15%, an increase in the relative strain at break of 60% and in the impact strength of 15% of the newly prepared nanobiocomposites with respect to the unfiled P3HB. The produced hybrid nanobiocomposites combined the best features induced by the plasticizing effect of polyurethane and the formation of P3HB-montmorillonite-polyurethane (P3HB-PU-MMT) adducts, which resulted in the improvement of the thermal and mechanical properties.

Autophagy-Modulated Biomaterial: A Robust Weapon for Modulating the Wound Environment to Promote Skin Wound Healing

Autophagy, a self-renewal mechanism, can help to maintain the stability of the intracellular environment of organisms. Autophagy can also regulate several cellular functions and is strongly related to the onset and progression of several diseases. Wound healing is a biological process that is coregulated by different types of cells. However, it is troublesome owing to prolonged treatment duration and poor recovery. In recent years, biomaterials have been reported to influence the skin wound healing process by finely regulating autophagy. Biomaterials that regulate autophagy in various cells involved in skin wound healing to regulate the differentiation, proliferation and migration of cells, inflammatory responses, oxidative stress and formation of the extracellular matrix (ECM) have emerged as a key method for improving the tissue regeneration ability of biomaterials. During the inflammatory phase, autophagy enhances the clearance of pathogens from the wound site and leads to macrophage polarization from the M1 to the M2 phenotype, thus preventing enhanced inflammation that can lead to further tissue damage. Autophagy plays important roles in facilitating the formation of extracellular matrix (ECM) during the proliferative phase, removing excess intracellular ROS, and promoting the proliferation and differentiation of endothelial cells, fibroblasts, and keratinocytes. This review summarizes the close association between autophagy and skin wound healing and discusses the role of biomaterial-based autophagy in tissue regeneration. The applications of recent biomaterials designed to target autophagy are highlighted, including polymeric materials, cellular materials, metal nanomaterials, and carbon-based materials. A better understanding of biomaterial-regulated autophagy and skin regeneration and the underlying molecular mechanisms may open new possibilities for promoting skin regeneration. Moreover, this can lay the foundation for the development of more effective therapeutic approaches and novel biomaterials for clinical applications.

Radiopaque Crystalline, Non-Crystalline and Nanostructured Bioceramics

Radiopacity is sometimes an essential characteristic of biomaterials that can help clinicians perform follow-ups during pre- and post-interventional radiological imaging. Due to their chemical composition and structure, most bioceramics are inherently radiopaque but can still be doped/mixed with radiopacifiers to increase their visualization during or after medical procedures. The radiopacifiers are frequently heavy elements of the periodic table, such as Bi, Zr, Sr, Ba, Ta, Zn, Y, etc., or their relevant compounds that can confer enhanced radiopacity. Radiopaque bioceramics are also intriguing additives for biopolymers and hybrids, which are extensively researched and developed nowadays for various biomedical setups. The present work aims to provide an overview of radiopaque bioceramics, specifically crystalline, non-crystalline (glassy), and nanostructured bioceramics designed for applications in orthopedics, dentistry, and cancer therapy. Furthermore, the modification of the chemical, physical, and biological properties of parent ceramics/biopolymers due to the addition of radiopacifiers is critically discussed. We also point out future research lacunas in this exciting field that bioceramists can explore further.

Synthesis of Antibacterial Hybrid Hydroxyapatite/Collagen/Polysaccharide Bioactive Membranes and Their Effect on Osteoblast Culture

Inspired by the composition and confined environment provided by collagen fibrils during bone formation, this study aimed to compare two different strategies to synthesize bioactive hybrid membranes and to assess the role the organic matrix plays as physical confinement during mineral phase deposition. The hybrid membranes were prepared by (1) incorporating calcium phosphate in a biopolymeric membrane for in situ hydroxyapatite (HAp) precipitation in the interstices of the biopolymeric membrane as a confined environment (Methodology 1) or (2) adding synthetic HAp nanoparticles (SHAp) to the freshly prepared biopolymeric membrane (Methodology 2). The biopolymeric membranes were based on hydrolyzed collagen (HC) and chitosan (Cht) or κ-carrageenan (κ-carr). The hybrid membranes presented homogeneous and continuous dispersion of the mineral particles embedded in the biopolymeric membrane interstices and enhanced mechanical properties. The importance of the confined spaces in biomineralization was confirmed by controlled biomimetic HAp precipitation via Methodology 1. HAp precipitation after immersion in simulated body fluid attested that the hybrid membranes were bioactive. Hybrid membranes containing Cht were not toxic to the osteoblasts. Hybrid membranes added with silver nanoparticles (AgNPs) displayed antibacterial action against different clinically important pathogenic microorganisms. Overall, these results open simple and promising pathways to develop a new generation of bioactive hybrid membranes with controllable degradation rates and antimicrobial properties.

Nanomaterials-Based Combinatorial Therapy as a Strategy to Combat Antibiotic Resistance

Since the discovery of antibiotics, humanity has been able to cope with the battle against bacterial infections. However, the inappropriate use of antibiotics, the lack of innovation in therapeutic agents, and other factors have allowed the emergence of new bacterial strains resistant to multiple antibiotic treatments, causing a crisis in the health sector. Furthermore, the World Health Organization has listed a series of pathogens (ESKAPE group) that have acquired new and varied resistance to different antibiotics families. Therefore, the scientific community has prioritized designing and developing novel treatments to combat these ESKAPE pathogens and other emergent multidrug-resistant bacteria. One of the solutions is the use of combinatorial therapies. Combinatorial therapies seek to enhance the effects of individual treatments at lower doses, bringing the advantage of being, in most cases, much less harmful to patients. Among the new developments in combinatorial therapies, nanomaterials have gained significant interest. Some of the most promising nanotherapeutics include polymers, inorganic nanoparticles, and antimicrobial peptides due to their bactericidal and nanocarrier properties. Therefore, this review focuses on discussing the state-of-the-art of the most significant advances and concludes with a perspective on the future developments of nanotherapeutic combinatorial treatments that target bacterial infections.

Accelerated Discovery of the Polymer Blends for Cartilage Repair through Data-Mining Tools and Machine-Learning Algorithm

In designing successful cartilage substitutes, the selection of scaffold materials plays a central role, among several other important factors. In an empirical approach, the selection of the most appropriate polymer(s) for cartilage repair is an expensive and time-consuming affair, as traditionally it requires numerous trials. Moreover, it is humanly impossible to go through the huge library of literature available on the potential polymer(s) and to correlate the physical, mechanical, and biological properties that might be suitable for cartilage tissue engineering. Hence, the objective of this study is to implement an inverse design approach to predict the best polymer(s)/blend(s) for cartilage repair by using a machine-learning algorithm (i.e., multinomial logistic regression (MNLR)). Initially, a systematic bibliometric analysis on cartilage repair has been performed by using the bibliometrix package in the R program. Then, the database was created by extracting the mechanical properties of the most frequently used polymers/blends from the PoLyInfo library by using data-mining tools. Then, an MNLR algorithm was run by using the mechanical properties of the polymers, which are similar to the cartilages, as the input and the polymer(s)/blends as the predicted output. The MNLR algorithm used in this study predicts polyethylene/polyethylene-graftpoly(maleic anhydride) blend as the best candidate for cartilage repair.

Fermented Jussara: Evaluation of Nanostructure Formation, Bioaccessibility, and Antioxidant Activity

Among the species of plants present in the Atlantic Forest, the jussara (Euterpe edulis Mart.) stands out for the contents of bioactive compounds present in its composition. Fermentation processes can be essential in converting bioproducts and bioactive compounds, improving their biological properties. In addition, the improvement of procedures for the maintenance of the features of bioactive compounds has been a research focus in recent years, and the nanotechnology features that can potentially solve this issue have been highlighted among the most reviewed paths. The present work focused on tailoring nanostructures applying polyethylene oxide, assembling fermented jussara pulp nanofibers, and assessing their characteristics. The results revealed the formation of fermented jussara nanofibers with a diameter of 101.2 ± 26.2 nm. Also, the obtained results allow us to state that it is possible to maintain or even increase the antioxidant activity of anthocyanins and their metabolites after fermentation processes.

Magnesium-Based Alloys Used in Orthopedic Surgery

Magnesium (Mg)-based alloys have become an important category of materials that is attracting more and more attention due to their high potential use as orthopedic temporary implants. These alloys are a viable alternative to nondegradable metals implants in orthopedics. In this paper, a detailed overview covering alloy development and manufacturing techniques is described. Further, important attributes for Mg-based alloys involved in orthopedic implants fabrication, physiological and toxicological effects of each alloying element, mechanical properties, osteogenesis, and angiogenesis of Mg are presented. A section detailing the main biocompatible Mg-based alloys, with examples of mechanical properties, degradation behavior, and cytotoxicity tests related to in vitro experiments, is also provided. Special attention is given to animal testing, and the clinical translation is also reviewed, focusing on the main clinical cases that were conducted under human use approval.

In situ synthesis of hydroxyapatite nanorods on graphene oxide nanosheets and their reinforcement in biopolymer scaffold

Introduction

It is urgently needed to develop composite bone scaffold with excellent mechanical properties and bioactivity in bone tissue engineering. Combining graphene oxide (GO) and hydroxyapatite (HAP) for the reinforcement of biopolymer bone scaffold has emerged as a promising strategy. However, the dispersion of GO and HAP remains to be a big challenge.

Objectives

In this present work, the mechanical properties of GO and the bioactivity of and HAP were combined respectively via in situ synthesis for reinforcing biopolymer bone scaffold.

Methods

GO nanosheets were employed to in situ synthesize GO-HAP nanocomposite via hydrothermal reaction, in which their abundant oxygen-containing groups served as anchor sites for the chelation of Ca2+ and then Ca2+ absorbed HPO42- via electrovalent bonding to form homogeneously dispersed HAP nanorods. Thereby, the GO-HAP nanocomposite was blended with biopolymer poly-L-lactic acid (PLLA) for fabricating biopolymer scaffold by selective laser sintering (SLS).

Results

GO nanosheets were uniformly decorated with HAP nanorods, which were about 60 nm in length and 5 nm in diameter. The compressive strength and modulus of PLLA/12%GO-HAP were significantly increased by 53.71% and 98.80% compared to the pure PLLA scaffold, respectively, explained on the base of pull out, crack bridging, deflection and pinning mechanisms. Meanwhile, the mineralization experiments indicated the PLLA/GO-HAP scaffold displayed good bioactivity by inducing the formation of apatite layer. Besides, cell culturing experiments demonstrated the favorable cytocompatibility of scaffold by promoting cell adhesion and proliferation.

Conclusions

The present findings show the potential of PLLA/GO-HAP composite scaffold via in situ synthesis in bone tissue engineering.

Fabrication and characterization of 3D printing scaffold technology by extract oils from plant and its applications in the cardiovascular blood

Extract oils from plants used in 3D polysaccharides modified with natural protein polymer modified polymer scaffolds can help to reduce blood pressure. This study aimed to use extract oils from plant (EOP)as blood pressure-reducing, bind them to magnetic iron nanoparticles (Fe3O4@NPs), then bind them to polymeric 3D print scaffolds [chitosan, polylactic acid, and polyurethane (CS/PLA/PU), modified with natural protein and finally separate them. This method made it possible to investigate different variables for nanoparticles. In this project, synthesis polymer, modified gelatin (Mo-Ge), PEGylation, extract oils from plant loading and release process in nanocarrier with different concentrations were examined and cell proliferation was optimized. The results show that 75% of the extract oils from plant loaded on iron magnetic nanoparticles containing PEGylated polymer scaffolds was released. Cell proliferation was performed for the sample. In this process, modification of scaffolding with polysaccharides modified with natural protein and extract oils from plant increased the efficiency of nanoparticles among the studied Allium sativum and Zingiber officinale. The size of A. sativum and Z. officinale were 29.833 nm and 150.02 nm size, respectively. These behaved very similarly to each other and A. sativum had the biggest effect in lowering blood pressure. The application of extract oils from plant in 3D mode scaffolding has not been studied before and this is the first analysis to do so, using nanoparticles.

Poly(L-Lactic Acid) Composite with Surface-Modified Magnesium Hydroxide Nanoparticles by Biodegradable Oligomer for Augmented Mechanical and Biological Properties

Poly(L-lactic acid) (PLLA) has attracted a great deal of attention for its use in biomedical materials such as biodegradable vascular scaffolds due to its high biocompatibility. However, its inherent brittleness and inflammatory responses by acidic by-products of PLLA limit its application in biomedical materials. Magnesium hydroxide (MH) has drawn attention as a potential additive since it has a neutralizing effect. Despite the advantages of MH, the MH can be easily agglomerated, resulting in poor dispersion in the polymer matrix. To overcome this problem, oligo-L-lactide-ε-caprolactone (OLCL) as a flexible character was grafted onto the surface of MH nanoparticles due to its acid-neutralizing effect and was added to the PLLA to obtain PLLA/MH composites. The pH neutralization effect of MH was maintained after surface modification. In an in vitro cell experiment, the PLLA/MH composites including OLCL-grafted MH exhibited lower platelet adhesion, cytotoxicity, and inflammatory responses better than those of the control group. Taken together, these results prove that PLLA/MH composites including OLCL-grafted MH show excellent augmented mechanical and biological properties. This technology can be applied to biomedical materials for vascular devices such as biodegradable vascular scaffolds.

Statistical and Machine Learning-Driven Optimization of Mechanical Properties in Designing Durable HDPE Nanobiocomposites

The selection of nanofillers and compatibilizing agents, and their size and concentration, are always considered to be crucial in the design of durable nanobiocomposites with maximized mechanical properties (i.e., fracture strength (FS), yield strength (YS), Young’s modulus (YM), etc). Therefore, the statistical optimization of the key design factors has become extremely important to minimize the experimental runs and the cost involved. In this study, both statistical (i.e., analysis of variance (ANOVA) and response surface methodology (RSM)) and machine learning techniques (i.e., artificial intelligence-based techniques (i.e., artificial neural network (ANN) and genetic algorithm (GA)) were used to optimize the concentrations of nanofillers and compatibilizing agents of the injection-molded HDPE nanocomposites. Initially, through ANOVA, the concentrations of TiO₂ and cellulose nanocrystals (CNCs) and their combinations were found to be the major factors in improving the durability of the HDPE nanocomposites. Further, the data were modeled and predicted using RSM, ANN, and their combination with a genetic algorithm (i.e., RSM-GA and ANN-GA). Later, to minimize the risk of local optimization, an ANN-GA hybrid technique was implemented in this study to optimize multiple responses, to develop the nonlinear relationship between the factors (i.e., the concentration of TiO₂ and CNCs) and responses (i.e., FS, YS, and YM), with minimum error and with regression values above 95%.

3D magnetic nanocomposite scaffolds enhanced the osteogenic capacities of rat bone mesenchymal stem cells in vitro and in a rat calvarial bone defect model by promoting cell adhesion

Magnetic scaffolds incorporated with iron oxide nanoparticles (IONPs) are biocompatible and present excellent osteogenic properties. However, the underlying mechanism is unclear. In this study, 3D-printed poly(lactic-co-glycolic acid) scaffolds were coated with IONPs using layer-by-layer assembly (Fe-scaffold) to prepare magnetic scaffolds. The effects of this modification on osteogenesis were investigated by comparison with untreated scaffolds (Uncoated-scaffold). The results showed that the proliferation of rat bone mesenchymal stem cells (rBMSCs) on the Fe-scaffold was enhanced compared with those on the Uncoated-scaffold (p < 0.05). The alkaline phosphatase activity and expression levels of osteogenic-related genes of cells on the Fe-scaffold were higher than those on the Uncoated-scaffold (p < 0.05). Fe-scaffold was found to promote the cell adhesion compared with Uncoated-scaffold, including increasing the adhered cell number, promoting cell spreading and upregulating the expression levels of adhesion-related genes integrin α1 and β1 and their downstream signaling molecules FAK and ERK1/2 (p < 0.05). Moreover, the amount of new bone formed in rat calvarial defects at 8 weeks decreased in the order: Fe-scaffold > Uncoated-scaffold > Blank-control (samples whose defects were left empty) (p < 0.05). Therefore, 3D magnetic nanocomposite scaffolds enhanced the osteogenic capacities of rBMSCs in vitro and in a rat calvarial bone defect model by promoting cell adhesion. The mechanisms were attributed to the alteration in its hydrophilicity, surface roughness, and chemical composition.

Silver in biology and medicine: opportunities for metallomics researchers

The antibacterial properties of silver have been known for centuries and the threat of antibiotic-resistant bacteria has led to renewed focus on the noble metal. Silver is now commonly included in a range of household and medical items to imbue them with bactericidal properties. Despite this, the chemical fate of the metal in biological systems is poorly understood. Silver(I) is a soft metal with high affinity for soft donor atoms and displays much similarity to the chemistry of Cu(I). In bacteria, interaction of silver with the cell wall/membrane, DNA, and proteins and enzymes can lead to cell death. Additionally, the intracellular generation of reactive oxygen species by silver is posited to be a significant antimicrobial action. While the antibacterial action of silver is well known, bacteria found in silver mines display resistance against it through use of a protein ensemble thought to have been specifically developed for the metal, highlighting the need for judicious use. In mammals, ∼10-20% of ingested silver is retained by the body and thought to predominantly localize in the liver or kidneys. Chronic exposure can result in argyria, a condition characterized by blue staining of the skin, resulting from subdermal deposition of silver [as Ag(0)/sulfides], but more insidious side effects, such as inclusions in the brain, seizures, liver/kidney damage, and immunosuppression, have also been reported. Here, we hope to highlight the current understanding of the biological chemistry of silver and the necessity for continued study of these systems to fill existing gaps in knowledge.

Recent Strategies and Applications for l-Asparaginase Confinement

l-asparaginase (ASNase, EC 3.5.1.1) is an aminohydrolase enzyme with important uses in the therapeutic/pharmaceutical and food industries. Its main applications are as an anticancer drug, mostly for acute lymphoblastic leukaemia (ALL) treatment, and in acrylamide reduction when starch-rich foods are cooked at temperatures above 100 °C. Its use as a biosensor for asparagine in both industries has also been reported. However, there are certain challenges associated with ASNase applications. Depending on the ASNase source, the major challenges of its pharmaceutical application are the hypersensitivity reactions that it causes in ALL patients and its short half-life and fast plasma clearance in the blood system by native proteases. In addition, ASNase is generally unstable and it is a thermolabile enzyme, which also hinders its application in the food sector. These drawbacks have been overcome by the ASNase confinement in different (nano)materials through distinct techniques, such as physical adsorption, covalent attachment and entrapment. Overall, this review describes the most recent strategies reported for ASNase confinement in numerous (nano)materials, highlighting its improved properties, especially specificity, half-life enhancement and thermal and operational stability improvement, allowing its reuse, increased proteolysis resistance and immunogenicity elimination. The most recent applications of confined ASNase in nanomaterials are reviewed for the first time, simultaneously providing prospects in the described fields of application.

Morphology and Electronic Properties of Semiconducting Polymer and Branched Polyethylene Blends

A new strategy for influencing the solid-state morphology of conjugated polymers was developed through physical blending with a low-molecular-weight branched polyethylene. This nontoxic and low-boiling-point additive was blended with a high-charge-mobility diketopyrrolopyrrole-based conjugated polymer, and a detailed investigation of the new blended materials was performed by various characterization tools, including X-ray diffraction, UV-vis spectroscopy, and atomic force microscopy. Interestingly, the branched additive was shown to reduce the crystallinity of the conjugated polymer while promoting aggregation and phase separation in the solid state. Upon thermal removal of the olefinic additive, the thin films maintained a lower crystallinity and aggregated morphology in comparison to a nonblended polymer. The semiconducting performance of the new branched polyethylene/conjugated polymer blends was also investigated in organic field-effect transistors, which showed a stable charge mobility of around 0.3 cm² V^-1 s^-1 without thermal annealing, independent of the blending ratio. Furthermore, using the new polyethylene-based additive, the concentration of a conjugated polymer required for the fabrication of organic field-effect transistor devices was reduced down to 0.05 wt %, without affecting charge transport, which represents a significant improvement compared to usual concentrations used for solution deposition. Our results demonstrate that the physical blending of a conjugated polymer with nontoxic, low-molecular-weight branched polyethylene is a promising strategy for the modification and fine-tuning of the solid-state morphology of conjugated polymers without sacrificing their charge-transport properties, thus creating new opportunities for the large-scale processing of organic semiconductors.

Enhanced osteoinduction of electrospun scaffolds with assemblies of hematite nanoparticles as a bioactive interface

Purpose

Electrospun scaffolds have been studied extensively for their potential use in bone tissue engineering. However, their hydrophobicity and relatively low matrix stiffness constrain their osteoinduction capacities. In the present study, we studied polymer electrospun scaffolds coated with hydrophilic hematite nanoparticles (αFeNPs) constructed using layer-by-layer (LbL) assembly to construct a bioactive interface between the scaffolds and cells, to improve the osteoinduction capacities of the scaffolds.

Materials and methods

The morphology of the αFeNPs was assessed. Surface properties of the scaffolds were tested by X-ray photoelectron spectroscopy (XPS), surface water contact angle, and in vitro protein adsorption test. The stiffness of the coating was tested using an atomic force microscope (AFM). In vitro cell assays were performed using rat adipose-derived stem cells (ADSCs).

Results

Morphology characterizations showed that αFeNPs assembled on the surface of the scaffold, where the nano assemblies improved hydrophilicity and increased surface roughness, with increased surface stiffness. Enhanced initial ADSC cell spread was found in the nano assembled groups. Significant enhancements in osteogenic differentiation, represented by enhanced alkaline phosphatase (ALP) activities, elevated expression of osteogenic marker genes, and increased mineral synthesis by the seeded ADSCs, were detected. The influencing factors were attributed to the better hydrophilicity, rougher surface topography, and harder interface stiffness. In addition, the presence of nanoparticles was believed to provide better cell adhesion sites.

Conclusion

The results suggested that the construction of a bioactive interface by LbL assembly using αFeNPs on traditional scaffolds should be a promising method for bone tissue engineering.

The reproductive and developmental toxicity of nanoparticles: A bibliometric analysis

Because of the advantages of nanoparticles (NPs) in a variety of industrial, biomedical, and consumer applications, they are intentionally (such as in medicine) or unintentionally (environment exposure) introduced into the human body. However, to date, the detrimental effects of NPs are still unclear, especially in reproductive and developmental toxicity. In this study, we researched 266 articles related to the reproductive and developmental toxicity of NPs from 2006 to December 2016 based on the database of the Web of Science. According to the bibliometric analysis, we found that China and the United States were the leading countries in this field and the major research trends might focus on the pathogenesis of NPs, such as oxidative stress, inflammation, and DNA damage. By this analysis, we provide new insights into the research trends and characteristics of the field.