Influence of temperature on the formation and encapsulation of gold nanoparticles using a temperature-sensitive template.
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ABSTRACT:
SUBMITTER: Tan NP
PROVIDER: S-EPMC4610952 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundGold nanoparticles are useful tools for biological applications due to their attractive physical and chemical properties. Their applications can be further expanded when they are functionalized with biological molecules. The biological molecules not only provide the interfaces for interactions between nanoparticles and biological environment, but also contribute their biological functions to the nanoparticles. Therefore, we used self-assembling protein nanoparticles (SAPNs) to encapsulate gold nanoparticles. The protein nanoparticles are formed upon self-assembly of a protein chain that is composed of a pentameric coiled-coil domain at the N-terminus and trimeric coiled-coil domain at the C-terminus. The self-assembling protein nanoparticles form a central cavity of about 10 nm in size, which is ideal for the encapsulation of gold nanoparticles with similar sizes.ResultsWe have used SAPNs to encapsulate several commercially available gold nanoparticles. The hydrodynamic size and the surface coating of gold nanoparticles are two important factors influencing successful encapsulation by the SAPNs. Gold nanoparticles with a hydrodynamic size of less than 15 nm can successfully be encapsulated. Gold nanoparticles with citrate coating appear to have stronger interactions with the proteins, which can interfere with the formation of regular protein nanoparticles. Upon encapsulation gold nanoparticles with polymer coating interfere less strongly with the ability of the SAPNs to assemble into nanoparticles. Although the central cavity of the SAPNs carries an overall charge, the electrostatic interaction appears to be less critical for the efficient encapsulation of gold nanoparticles into the protein nanoparticles.ConclusionsThe SAPNs can be used to encapsulate gold nanoparticles. The SAPNs can be further functionalized by engineering functional peptides or proteins to either their N- or C-termini. Therefore encapsulation of gold nanoparticles into SAPNs can provide a useful platform to generate a multifunctional biodevices.
| S-EPMC3502577 | biostudies-literature
Project description:Heating on the microscale using focused lasers gave rise to recent applications, e.g., in biomedicine, biology and microfluidics, especially using gold nanoparticles as efficient nanoabsorbers of light. However, such an approach naturally leads to nonuniform, Gaussian-like temperature distributions due to the diffusive nature of heat. Here, we report on an experimental means to generate arbitrary distributions of temperature profiles on the micrometric scale (e.g. uniform, linear, parabolic, etc) consisting in illuminating a uniform gold nanoparticle distribution on a planar substrate using spatially contrasted laser beams, shaped using a spatial light modulator (SLM). We explain how to compute the light pattern and the SLM interferogram to achieve the desired temperature distribution, and demonstrate the approach by carrying out temperature measurements using quantitative wavefront sensing.
| S-EPMC6420633 | biostudies-literature
Project description:Gold nanoparticle-coated Pluronic-b-poly(L-lysine) nanoparticles (Pluronic-PLL@Au NPs) were synthesized via an easy one-step method and employed as carriers for the delivery of paclitaxel (PTX) in chemo-photothermal therapy, in which Pluronic-PLL acts as the reductant for the formation of AuNPs without the need for an additional reducing agent.MethodsThe deposition of AuNPs on the surface of Pluronic-PLL micelles and the thermal response of the system were followed via ultraviolet-visible spectroscopy and dynamic light scattering. Calcein-AM and MTT assays were used to study the cell viability of MDA-MB-231 cells treated with PTX-loaded Pluronic-PLL@Au NPs, and we then irradiated the cells with NIR light.ResultsAn obvious temperature response was observed for the Pluronic-PLL@Au NPs. Blood compatibility and in vitro cytotoxicity assays confirmed that the Pluronic-PLL@Au NPs have excellent biocompatibility. Compared to Taxol, the PTX-loaded Pluronic-PLL@Au NPs exhibited higher cytotoxicity in MDA-MB-231 cells. All of these results and confocal laser scanning microscopy analysis results suggest that Pluronic-PLL@Au NPs greatly enhance the cellular uptake efficiency of the drug.ConclusionAs confirmed by in vitro and in vivo studies, the combination of chemotherapy and photothermal therapy can cause more damage than chemo- or photothermal therapy did alone, demonstrating the synergistic effect of chemo-photothermal treatment. Thus, the as-prepared Pluronic-PLL@Au NPs are promising for chemo-photothermal therapy.
| S-EPMC5695141 | biostudies-literature
Project description:BackgroundOvarian cancer is one of the deadliest gynecological malignancies. While the overall survival of ovarian cancer patients has slightly improved in recent years in the developed world, it remains clinically challenging due to its frequent late diagnosis and the lack of reliable diagnostic and/or prognostic markers. The aim of this study was to identify potential new molecular target proteins (NMTPs) responsible for the poor outcomes. When nanoparticles (NP) are exposed to biological fluids, a protein coat, termed the protein corona (PC), forms around the NP, and the PC represents a tool to identify NMTPs. This study investigates the influence of pre-processing conditions, such as lysis conditions and serum/plasma treatment, on the PC composition and the resulting identification of NMTPs.ResultsUsing gel electrophoresis, pre-processing conditions, including cell-lysis techniques and enrichment of low-abundance proteins (LAPs) by immunocentrifugation of serum/plasma, were shown to alter the relative amounts and compositions of proteins. PCs formed when 20 nm gold-NPs (GNPs) were incubated with lysate proteins from either RIPA- or urea lysis. Proteomic analysis of these PCs showed 2-22-fold enrichment of NMTPs in PCs from urea lysates as compared to RIPA lysates. Enriched NMTPs were then classified as cellular components, biological and molecular functions-associated proteins. The impact of enriched LAPs (eLAPs) on both PC composition and NMTP identification was shown by comparative proteomic analysis of original plasma, eLAPs, and PCs derived from eLAPs; eLAPs-PCs enhanced the abundance of NMTPs approximately 13%. Several NMTPs, including gasdermin-B, dermcidin, and kallistatin, were identified by this method demonstrating the potential use of this PC approach for molecular target discovery.ConclusionThe current study showed that the pre-processing conditions modulate PC composition and can be used to enhance identification of NMTPs.
| S-EPMC7788026 | biostudies-literature
Project description:When nanoparticles (NPs) are exposed to biological media, proteins are adsorbed, forming a so-called protein corona (PC). This cloud of protein aggregates hampers the targeting and transport capabilities of the NPs, thereby compromising their biomedical applications. Therefore, there is a high interest in the development of technologies that allow control over PC formation, as this would provide a handle to manipulate NPs in biological fluids. We present a strategy that enables the reversible disruption of the PC using external stimuli, thereby allowing a precise regulation of NP cellular uptake. The approach, demonstrated for gold nanoparticles (AuNPs), is based on a biorthogonal, supramolecular host-guest interactions between an anionic dye bound to the AuNP surface and a positively charged macromolecular cage. This supramolecular complex effectively behaves as a zwitterionic NP ligand, which is able not only to prevent PC formation but also to disrupt a previously formed hard corona. With this supramolecular stimulus, the cellular internalization of AuNPs can be enhanced by up to 30-fold in some cases, and even NP cellular uptake in phagocytic cells can be regulated. Additionally, we demonstrate that the conditional cell uptake of purposely designed gold nanorods can be used to selectively enhance photothermal cell death.
| S-EPMC7254833 | biostudies-literature
Project description:Synthesis of gold nanoparticles (GNP) by reacting chloroauric acid (HAuCl4) and Pluronic F127 was thoroughly investigated. The rate of reduction of HAuCl4 and the yield and morphology of GNP strongly depended on the concentration of the reactants and sodium chloride, as well as pH and temperature. Upon completion of the reaction heterogeneous mixtures of small GNP of defined shape and Pluronic aggregates were formed. GNP were separated from the excess of Pluronic by centrifugal filtration. Under optimized conditions the GNP were small (ca. 80 nm), uniform (PDI ~0.09), strongly negatively charged (?-potential -30 mV) and nearly spherical. They were stable in distilled water and phosphate-buffered saline. Purified GNP contained ~13% by weight of an organic component, yet presence of polypropylene oxide was not detected suggesting that Pluronic was not adsorbed on their surface. Analysis of the soluble products suggested that the copolymer undergoes partial degradation accompanied by cleavage of the C-O bonds and appearance of new primary hydroxyl groups. The reaction involves formation of free radicals and hydroperoxides depends on the oxygen concentration. GNP did not form at 4 °C when the micellization of Pluronic was abolished reinforcing the role of the copolymer self-assembly. In conclusion, this work provides insight into the mechanism of HAuCl4 reduction and GNP formation in the presence of Pluronic block copolymers. It is useful for improving the methods of manufacturing uniform and pure GNP that are needed as nanoscale building blocks in nanomedicine applications.
| S-EPMC6835800 | biostudies-literature
Project description:Glucose- and temperature-sensitive polymers of a phenylboronic acid derivative and diethylene glycol dimethacrylate (poly(3-acrylamidophenyl boronic acid-b-diethylene glycol methyl ether methacrylate); p(AAPBA-b-DEGMA)) were prepared by reversible addition-fragmentation chain transfer polymerization. Successful polymerization was evidenced by 1H nuclear magnetic resonance and infrared spectroscopy, and the polymers were further explored in terms of their glass transition temperatures and by gel permeation chromatography (GPC). The materials were found to be temperature sensitive, with lower critical solution temperatures in the region of 12°C-47°C depending on the monomer ratio used for reaction. The polymers could be self-assembled into nanoparticles (NPs), and the zeta potential and size of these particles were determined as a function of temperature and glucose concentration. Subsequently, the optimum NP formulation was loaded with insulin, and the drug release was studied. We found that insulin was easily encapsulated into the p(AAPBA-b-DEGMA) NPs, with a loading capacity of ~15% and encapsulation efficiency of ~70%. Insulin release could be regulated by changes in temperature and glucose concentration. Furthermore, the NPs were non-toxic both in vitro and in vivo. Finally, the efficacy of the formulations at managing blood glucose levels in a murine hyperglycemic diabetes model was studied. The insulin-loaded NPs could reduce blood glucose levels over an extended period of 48 h. Since they are both temperature and glucose sensitive and offer a sustained-release profile, these systems may comprise potent new formulations for insulin delivery.
| S-EPMC5457184 | biostudies-literature
Project description:Functionalized, dendrimer-stabilized gold nanoparticles (Au DSNPs) are of scientific and technological interest for biological applications. In this work, we show that acetamide-functionalized Au DSNPs can be formed by acetylation of amine-terminated poly(amidoamine) (PAMAM) dendrimers of generation 5 (G5.NH(2)) complexed with Au(III) ions (AuCl(4) (-)). In addition, hydroxyl-functionalized Au DSNPs can be formed by simply mixing the glycidol hydroxyl-terminated G5 dendrimers (G5.NGlyOH) with HAuCl(4). In both cases, no additional reducing agents were needed and the reactions were completed at room temperature. We also show that Alexa Fluor 594 dye-functionalized Au DSNPs can be formed by acetylation of Alexa Fluor 594-conjugated, amine-terminated G5 dendrimers complexed with HAuCl(4). All of these functionalized Au DSNPs are water-soluble and stable. Fluorescence spectroscopy studies reveal that the Alexa Fluor 594-functionalized Au DSNPs retain similar fluorescence intensity to the Alexa Fluor 594-functionalized dendrimers that lack Au nanoparticles. These preparations of Au DSNPs provide a straightforward approach to synthesizing functionalized metal nanoparticles for biomedical applications.
| S-EPMC2736051 | biostudies-literature
Project description:Electromagnetized gold nanopartilces can facilitate hippocampal neurogenesis.
2021-02-19 | GSE167006 | GEO
Project description:Gold nanoparticle (AuNP) based colorimetric aptasensor have been developed for many analytes recently largely because of the ease of detection, high sensitivity, and potential for high-throughput analysis. Most of the target aptamers for detection have short sequences. However, the approach shows poor performance in terms of detection sensitivity for most of the long-sequence aptamers. To address this problem, for the first time, we split the 76 mer aptamer of 17β-estradiol into two short pieces to improve the AuNP based colorimetric sensitivity. Our results showed that the split P1 + P2 still retained the original 76 mer aptamer's affinity and specificity but increased the detection limit by 10-fold, demonstrating that as low as 0.1 ng/mL 17β-estradiol could be detected. The increased sensitivity may be caused by lower aptamer adsorption concentration and a lower affinity to the AuNPs of a short single-strand DNA (ssDNA) sequence. Our study provided a new way to use long-sequence aptamers to develop a highly sensitive AuNP-based colorimetric aptasensor.
| S-EPMC4271257 | biostudies-other