Nanotechnology, Science and Applications最新文献

Introductions: Ultrasonication can be used to synthesize nanosilica from silica derived from betung bamboo sticks and leaves. This study aimed to synthesize nanosilica from betung bamboo sticks and leaves by the use of ultrasonication and to characterize the nanosilica produced.

Methods: The main materials used in this study were bamboo sticks and leaves. Betung bamboo sticks and leaves were sun-dried and then burned separately without adding fuel to produce charcoal. Then the produced charcoal was burned at a temperature of 700°C for 6 hours in a furnace to produce ash. Silica was extracted from furnace ash using reflux methods. The production of nanosilica from the silica derived from the betung bamboo sticks and leaves was carried out using ultrasonication.

Results: The yield of silica from sticks and leaves was based on ash dry weight 45.73% and 79.93%, respectively. The nanosilica derived from betung bamboo sticks had a particle size in the range of 169.87-1479.50 nm, with an average size of 502.35 nm and a particle dispersion index value of 0.1420. Nanosilica derived from betung bamboo leaves had a particle size in the range of 234.49-851.36 nm, with an average size of 472.67 nm and a particle dispersion index value of 0.0670. Scanning electron microscopy analysis showed that silica from betung bamboo sticks and leaves still agglomerated. The particle size of silica could minimize through ultrasonication to synthesize nanosilica.

Discussions: X-ray diffraction analysis showed that the structure of nanosilica differed from that of silica, and it appeared to be semicrystalline. The ultrasonication method for the synthesis of nanosilica derived from betung bamboo sticks and leaves ash can produce nanosilica that has a semicrystalline phase. The use of surfactants in the process can make the size of the nanosilica particles more uniform and reduce the size of the nanoparticles produced.

Background: The limitations of optical microscopy to determine the cellular localization of label-free nanoparticles prevent a solid prediction of the cellular effect of particles intended for medical applications. To avoid the strong physicochemical changes associated with fluorescent labelling, which often result in differences in cellular uptake, efficiency and toxicity of particles, novel detection techniques are required.

Methods: In the present study, we determined the intracellular content of unlabeled SPIONs by analyzing refractive index (RI)-based images from holotomographic three-dimensional (3D) microscopy and side scatter data measured by flow cytometry. The results were compared with the actual cellular SPION amount as quantified by atomic emission spectroscopy (AES).

Results: Live cell imaging by 3D holotomographic microscopy demonstrated cell-specific differences in intracellular nanoparticle uptake in different pancreatic cell lines. Thus, treatment of PANC-1^{SMAD4 (1-4)} and PANC-1^{SMAD4 (2-6)} with SPIONs resulted in a significant increase in number of areas with higher RI, whereas in PANC-1, SUIT-2 and PaCa DD183, only a minimal increase of spots with high RI was observed. The increase in areas with high RI was in accordance with the SPION content determined by quantitative iron measurements using AES. In contrast, determination of the SPION amount by flow cytometry was strongly cell type-dependent and did not allow the discrimination between intracellular and membrane-bound SPIONs. However, flow cytometry is a very rapid and reliable method to assess the cellular toxicity and allows an estimation of the cell-associated SPION content.

Conclusion: Holotomographic 3D microscopy is a useful method to distinguish between intracellular and membrane-associated particles. Thus, it provides a valuable tool for scientists to evaluate the cellular localization and the particle load, which facilitates prediction of potential toxicity and efficiency of nanoparticles for medical applications.

Background: Recently, we reported the safety and biocompatibility of fluorescent diamond particles, FDP-NV-Z-800nm (FDP-NV) injected intravenously into rats, where no morbidity and mortality were noted over a period of 3 months. The acute effects of FDP-NV-800nm particles on cultured human endothelial and hepatic cells remain unexplored.

Purpose: In this study, we aimed to explore select cellular and biochemical functions in cultured human umbilical endothelial cells (HUVEC) and a human hepatic cancer cell line (HepG-2) exposed to FDP-NV-800 in vitro at exposure levels within the pharmacokinetics (Cmax and the nadir) previously reported in vivo.

Methods: Diverse cellular and biochemical functions were monitored, which cumulatively can provide insights into some vital cellular functions. Cell proliferation and migration were assessed by quantitative microscopy. Mitochondrial metabolic functions were tested by the MTT assay, and cytosolic esterase activity was studied by the calcein AM assay. Chaperons (CHOP), BiP and apoptosis (caspase-3 activation) were monitored by using Western blot (WB). MAPK Erk1/2 signaling was assessed by the detection of the phosphorylated form of the protein (P-Erk 1/2) and its translocation into the cell nucleus.

Results: At all concentrations tested (0.001-0.1mg/mL), FDP-NV did not affect any of the biomarkers of cell integrity of HepG2 cells. In contrast, the proliferation of HUVEC was affected at the highest concentration tested (0.1mg/mL, C_max). Exposure of HUVEC to (0.01 mg/mL) FDP-NV had a mild-moderate effect on cell proliferation as evident in the MTT assay and was absent when proliferation was assessed by direct cell counting or by using the calcein AM assays. In both cell types, exposure to the highest concentration (0.1 mg/mL) of FDP-NV did neither affect FBS-stimulated cell signaling (MAPK Erk1/2 phosphorylation) nor did it activate of Caspase 3.

Conclusion: Our data suggest that FDP-NV-800nm are largely biocompatible with HepG-2 cells proliferation within the pharmacokinetic data reported previously. In contrast, HUVEC proliferation at the highest exposure dose (0.1 mg/mL) responded adversely with respect to several biomarkers of cell integrity. However, since the C_max levels are very short-living, the risk for endothelial injury is likely minimal for slow rate cell proliferation such as endothelial cells.

Introduction: Biological research relies on the culture of mammalian cells, which are prone to changes in phenotype during experiments involving several passages of cells. In regenerative medicine, specifically, there is an increasing need to expand the characterisation landscape for stem cells by identifying novel stable markers. This paper reports on a novel electric cell-substrate impedance sensing-based electroanalytical diagram which can be used for the "electrical characterisation" of cell monolayers consisting of smooth muscle cells, endothelial cells or co-culture.

Materials and methods: Interdigitated electrodes were microfabricated using standard cleanroom procedures and integrated into cell chambers. Electrochemical impedance spectroscopy data were acquired for 2 vascular cell types after they formed monolayers on the electrodes.

Results and discussion: A Mean impedance per unit area vs Mean phase plots provided a reproducible, visually obvious and statistically significant method of characterising cell monolayers. This electroanalytic diagram has never been used in previous papers, but it confirms findings by other research groups using similar approaches that the complex impedance spectra of different cell type are different. Further work is required to determine whether this method could be extended to other cell types, and if this is the case, a library of "signature spectra" could be generated for "electrical characterisation" of cells.

Purpose: Metal-based nanoparticles (M-NPs) have attracted great attention in nanomedicine due to their capacity to amplify and improve the tumor targeting of medical beams. However, their simple, efficient, high-yield and reproducible production remains a challenge. Currently, M-NPs are mainly synthesized by chemical methods or radiolysis using toxic reactants. The waste of time, loss of material and potential environmental hazards are major limitations.

Materials and methods: This work proposes a simple, fast and green strategy to synthesize small, non-toxic and stable NPs in water with a 100% production rate. Ionizing radiation is used to simultaneously synthesize and sterilize the containing NPs solutions. The synthesis of platinum nanoparticles (Pt NPs) coated with biocompatible poly(ethylene glycol) ligands (PEG) is presented as proof of concept. The physicochemical properties of NPs were studied by complementary specialized techniques. Their toxicity and radio-enhancing properties were evaluated in a cancerous in vitro model. Using plasmid nanoprobes, we investigated the elementary mechanisms underpinning radio-enhancement.

Results and discussion: Pt NPs showed nearly spherical-like shapes and an average hydrodynamic diameter of 9 nm. NPs are zero-valent platinum successfully coated with PEG. They were found non-toxic and have the singular property of amplifying cell killing induced by γ-rays (14%) and even more, the effects of carbon ions (44%) used in particle therapy. They induce nanosized-molecular damage, which is a major finding to potentially implement this protocol in treatment planning simulations.

Conclusion: This new eco-friendly, fast and simple proposed method opens a new era of engineering water-soluble biocompatible NPs and boosts the development of NP-aided radiation therapies.

Recently, suspensions of several nanoparticles or nanocomposites have attained a vast field of application in biomedical research works in some specified conditions and clinical trials. These valuable suspensions, which allow the nanoparticles to disperse and act in homogenous and stable media, are named as nanofluids. Several studies have introduced the advantages of nanofluids in biomedical approaches in different fields. Few review articles have been reported for presenting an overview of the wide biomedical applications of nanofluids, such as diagnosis and therapy. The review is focused on nanosuspensions, as the nanofluids with solid particles. Major applications are focused on nanosuspension, which is the main type of nanofluids. So, concise content about major biomedical applications of nanofluids in drug delivery systems, imaging, and antibacterial activities is presented in this paper. For example, applying magnetic nanofluid systems is an important route for targeted drug delivery, hyperthermia, and differential diagnosis. Also, nanofluids could be used as a potential antibacterial agent to overcome antibiotic resistance. This study could be useful for presenting the novel and applicable methods for success in current medical practice.