Nanoparticle-Templated Assembly of Viral Protein Cages (original) (raw)
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Journal of Nanomaterials
In this letter, we report a new, one-step, rapid, and easy-to-implement method for the synthesis of PEGylated gold nanoparticles (PEG-AuNPs) having a narrow size distribution and very interesting plasmonic properties. Unmodified polyethylene glycol molecules with a molecular weight of 1000 g/mole (PEG1000) have been employed as reducing and capping agents for the synthesis of spherical gold nanoparticles having an average diameter of 35 nm, within a few minutes. The novelty of the herein proposed synthesis method consists in the fact that the synthesis takes place inside of a sealed bottle flask containing aqueous solutions of PEG1000, tetrachloroauric(III) acid (HAuCl4), and NaOH, placed in the center of a microwave oven, capable to provide a very uniform temperature environment. It turned out that, during the very short synthesis procedure (2 minutes), PEG 1000 suffers an oxidative transformation in such a manner that its terminal alcohol groups (-CH2-OH) are transformed in carbox...
Optimizing a Novel Method for Synthesizing Gold Nanoparticles: Biophysical Studies
Journal of Cancer Science & Therapy, 2012
The properties of Gold Nanoparticles (GNPs) make them useful for cancer therapy, diagnostics and imaging. For the application of GNPs in therapy and drug delivery there is a great necessity to synthesize known particle size of GNPs with simple methods. This study aimed to optimize a novel simple method for synthesizing GNPs.
Colloids and Surfaces A: Physicochemical and …, 2002
Recent developments in nanostructure self-assembly from gold and silver particles are reviewed. A brief historical background of the field is given, followed by a selection of topics which are of particular current interest. An overview of the preparation of thiol-stabilised gold and silver nanoparticles and their spontaneous self-organisation into well-ordered superlattices is presented. Distance-dependent metal insulator transitions in ensembles of nanoparticles are discussed, along with a previously unpublished measurement of optical properties of dithiol-linked thin films of gold nanoparticles. Recent approaches to more complex nano-architectures are reviewed, including the use of various templates and of DNA base pair recognition. Some aspects of nanoscopic surface chemistry of gold particles including the evolution of molecular recognition sites are reviewed. Current and potential future applications are discussed.
Journal of Nanoparticle Research, 2013
We have analyzed the titration process of gold nanoparticles with several amounts of protein A (0.3, 0.5, 1, 3, 6, and 9 lg/ml) in the presence of NaCl, which induces aggregation if the surface of particles is not fully covered with protein A. The colloidal solutions with different particle size (16, 18, 20, 33 nm) were synthesized by citrate reduction to be conjugated with protein A. UV-Visible spectroscopy was used to measure the absorption of the surface plasmon resonance of gold nanoparticles as a function of the concentration of protein A. Such dependence shows an aggregation region (0 \ x\6 lg/ml), where the amount of protein A was insufficient to cover the surface of particles, obtaining aggregation caused by NaCl. The next part is the stability region (x C 6 lg/ml), where the amount of protein used covers the surface of particles and protects it from the aggregation. In addition to that the ratio between the intensities of both: the aggregates and of the gold nanoparticle bands was plotted as a function of the concentration of protein A. It was determined that 6 lg/ml is a sufficient value of protein A to stabilize the gold nanoparticle-protein A system. This method provides a simple way to stabilize gold nanoparticles obtained by citrate reduction, with protein A.
The citrate reduction method of synthesis of gold nanoparticles (AuNPs) as introduced by Frens has been standardized to enable one to prepare AuNPs of desired dimension by controlling the composition of the reactants. The standardization has been made through characterization of the nanoparticles by UV-vis spectroscopy and from the transmission electron microscopic (TEM) measurements. Linearity of the plot of the plasmon absorption maximum ( max of the synthesized AuNPs against their diameter as measured from TEM, as well as the plot of max with the fractional concentration of citrate in the reaction mixture provides a convenient and easy route to dictate the size of the synthesized AuNPs from a control on the composition of the reactants. The standardization reveals that a calculated composition of citrate (in terms of fractional concentration) in the reaction mixture produces AuNPs of a desired dimension within the range of 15-60 nm. The diameter of the synthesized gold nanoparticles can be confirmed simply from the UV-vis spectrophotometric technique. This essentially makes the use of costly TEM unnecessary, at least for the primary purposes.
Encapsidation of Different Plasmonic Gold Nanoparticles by the CCMV Capsid Protein
Different types of gold nanoparticles have been synthesized that great potential in medical applications such as medical imaging, bio-analytical sensing and photothermal therapy. However, their stability, polydispersity and biocompatibility are major issues of concern. For example, the synthesis of gold nanorods, obtained through the elongated micelle process, produce them with a high positive surface charge that is cytotoxic. While gold nanoshells are unstable and within a few weeks they decompose due to Ostwald ripening. In this work, we report the self-assembly of the capsid protein of cowpea chlorotic mottle virus (CCMV) around spherical gold nanoparticles, gold nanorods and gold nanoshells to form virus-like particles (VLPs). All gold nanoparticles were synthesized or treated to give them a negative surface charge, so they can interact with the positive N-terminus of the capsid protein leading to the formation of the VLPs. To induce the protein self-assembly around the negative...
Chemical methods for the preparation of gold particles based nanostructures and nanocomposites
2008
In this thesis, the potential functional interactions of gold nanoparticles with organic, hybrid, inorganic and biological systems have been investigated. Nanoparticles with varying sizes have been synthesized following different preparation methods. Molecular-like (D < 2 nm), highly fluorescent few-atoms clusters were prepared by a slow reduction of gold salts in organic solvent, yielding a colloidal solution that can be easily redispersed in a variety of solvents and matrices, including sol-gel silica and a hybrid copolymer. The emission wavelength has a lifetime in the ns and can be tuned from the near UV to the whole visible range by adjusting the reaction parameters, and the luminescence is stable for months both in intensity and wavelength. Use of alternative precursors and solvents, influence of reaction temperature and purification methods are all currently being investigated, together with potential application as biolabels and sensitizers for rare-earth-based optical am...
Monodisperse Protein Stabilized Gold Nanoparticles via a Simple Photochemical Process
Journal of Physical Chemistry C, 2008
Protein stabilized, water soluble gold nanoparticles are essential for biomedicines and biotechnology. Bovine Serum Albumin (BSA) is one of the most abundant proteins. It has a remarkable ability of binding and transporting materials across cell membrane that makes it ideal for drug delivery and very useful for pharmaceutical industry. Herein, we explored the direct synthesis of BSA stabilized gold nanoparticles via a simple photochemical process. BSA stabilized gold nanoparticles are synthesized in one step, using Irgacure (I-2959) as photoinitiator. UV radiation facilitates the easy one step synthesis of protein stabilized gold nanoparticles without any denaturation of the protein, during the process. Polyacrylamide Gel (PAGE) shows that there is no difference in the bands height and mobility of native BSA and UV irradiated BSA. PAGE results are further confirmed by fluorescence spectroscopy of native and UV irradiated BSA. BSA/PEG (polyethylene glycol) mixed monolayer stabilized gold nanoparticles have also been prepared in one step using the photochemical process. Different ratios of PEG to BSA are used to evaluate the particle size and the size distribution of gold nanoparticles. Transmission electron microscope (TEM) and dynamic light scattering (DLS) confirm the presence of nearly monodisperse mixed layer stabilized gold nanoparticles.