Sage-Tips

How do you stabilize gold nanoparticles?

Abstract: Gold nanoparticles (AuNPs) were synthesized and stabilized using the one-pot method and growth seeding, through utilization of synthetic polymers, including poly(N-vinylpyrrolidone) (PVP), poly(ethylene glycol) (PEG), and poly(vinylcaprolactame) (PVCL), as well as natural polysaccharides, including gellan.

How can gold nanoparticles be prevented aggregation?

If particles have flocculated but not aggregated there are a few things that can be done to re-suspend them:

1. Adjust pH to recommended range.
2. Gentle sonication.
3. Alter surface chemistry through methods such as PEGylation which force steric stabilization.

What is required for even dispersion of DNA on gold particles?

The adsorption of DNA is affected by many factors such as salt or ionic strength (Storhoff et al., 1998; Cutler et al., 2012). Since both DNA and AuNPs are negatively charged, salt is needed to screen the long-ranged charge repulsion to enable DNA adsorption.

What causes gold nanoparticles to aggregate?

The surface charge of the gold nanoparticle becomes neutral, causing nanoparticles to aggregate. To minimize aggregation, the versatile surface chemistry of gold nanoparticles allows them to be coated with polymers, small molecules, and biological recognition molecules.

How does peg stabilize the nanoparticles?

PEG decreases the amount of attraction between NPs by increasing the steric distance between them and increasing hydrophilicity via ether repeats forming hydrogen bonds with solvent. Other benefits to PEGylation include modifying the size of the particle.

How do you stabilize nanoparticles?

Nanoparticles are commonly stabilized through the adsorption of a dispersant layer around the particle surface. The formation of a dispersant layer (adlayer) of appropriate thickness is crucial for the stabilization of suspensions containing high nanoparticle concentrations.

How can nanoparticle agglomeration be prevented?

Adding surfactant is good method to avoid agglomeration in nanoparticles. If you don’t want to add any surfactant, you can search for suitable plant extract. Some plant extracts acts as a reducing agent as well as capping agent.

How do you concentrate gold nanoparticle solution?

Procedure

1. Place aliquot of gold nanoparticle solution in appropriate centrifuge tube.*
2. Centrifuge the gold nanoparticles for 30 minutes using the appropriate G force depending on size of the gold nanoparticles, see Table I below.
3. Remove supernatant and re-suspend in appropriate volume of ultra-pure water.

How do you synthesis gold nanoparticles?

Synthesis of gold nanoparticles developed a synthetic method for creating AuNPs in 1951 by treating hydrogen tetrachloroaurate (HAuCl4) with citric acid in boiling water, where the citrate acts as both reducing and stabilizing agent (Scheme 2B).

What is the surface plasmon resonance of gold nanoparticles?

The surface plasmon resonance, a unique phenomenon to plasmonic (noble metal) nanoparticles leads to strong electromagnetic fields on the particle surface and consequently enhances all the radiative properties such as absorption and scattering.

Why is PEG used in drug delivery?

Polyethylene glycol (PEG) is widely utilized in drug delivery and nanotechnology due to its reported “stealth” properties and biocompatibility. It is generally thought that PEGylation allows particulate delivery systems and biomaterials to evade the immune system and thereby prolong circulation lifetimes.

What is the function of PEG?

PEG is commonly used as a precipitant for plasmid DNA isolation and protein crystallization. X-ray diffraction of protein crystals can reveal the atomic structure of the proteins. PEG is used to fuse two different types of cells, most often B-cells and myelomas in order to create hybridomas.

How can I conjugate thiols to gold nanoparticles?

Thiols have very strong affinity for gold surfaces and a thiol-modified oligonucleotide (or aptamer) can be conjugated by directly mixing the modified oligo with gold nanoparticles followed by a “salt-aging” procedure that facilitates the binding of the oligo to the gold surface.

Why do we use thiols to make modified oligonucleotides?

This is primarily due to the ease of synthesizing these modified oligonucleotides and the strong affinity of the thiol group for noble metal and chalcogenide surfaces. Such methods have been used for preparing stable oligonucleotide conjugates with Au ( 2 ), Au-coated Ag ( 17 ) and ZnS-coated CdSe ( 6 ) nanoparticles.

What are the applications of oligonucleotide functionalized gold nanoparticles?

Oligonucleotide functionalized gold nanoparticles are used in a wide range of applications, with the most common being as probes in bio assays for recognition and detection of other molecules.

Why do trithiols have a higher surface coverage in gold nanoparticles?

The higher surface coverage of III is thus attributed to the fact that trithiol groups bind to a gold nanoparticle surface more efficiently than the disulfide or monothiol moieties.