Advertisement

Topics

Carrier blocks using gold in biomedicine

10:19 EDT 1 Nov 2018 | BioNow

This can be taken advantage of by a conjugation to biomolecules, enabled by the chemical affinity of gold to thiol groups: biomolecules such as peptides, oligonucleotides, or antibodies, can be attached to gold surfaces by using covalent thiol bonding with or without spacer molecules. In any case, the gold surface must be accessible to the molecules directly or by means of ligand exchange (replacing surface ligands that are already present on the surface by molecules of higher affinity). The obvious advantage of ligand-free nano-gold or significantly lower ligand coverage is that molecules attach to a free gold surface most efficiently.Gold nanoparticles with the lowest possible ligand coverage are available by laser ablation at the moment of their generation. Using hybrid process chambers that combine laser ablation and conjugation, clean nano-gold can be conjugated with functional molecules with highest efficiency. Such conjugates can be used in all nano-gold applications that have been demonstrated in biotech research.Compared to chemically synthesized materials, laser-generated conjugates excel by their higher reactivity and lower toxicity, opening up a wider window for applications.Their surface coverage with bio-functional ligands is up to 5 times higher than that of chemically synthesized nano-gold In case of antibodies, DNA, or aptamers, applications benefit especially from the high specificity, caused by the higher ligand grafting density. The use of an aptamer directed against a prostate-specific membrane antigen (PSMA) for gold nanoparticle functionalization led to the same conclusion that conjugation efficiency is higher if the aptamers are bound to ligand-free gold nanoparticles. This is especially relevant, as in the case of aptamers, the high conjugation yield saves very precious material. During functionality testing, the ligand-covered gold conjugates were found to strain prostate cancer tissue as efficiently as conventional fluorophore-labelled probes, compared to a negative control Conjugating ligand-free gold nanoparticles with a short cell-penetrating peptide (CPP) allows the rapid design of cell-penetrating nanomarkers for intracellular bio-imaging.Since CPPs are typically cationic at neutral pH and highly charged, buffering pH at appropriate values during conjugation is important. Significantly enhanced penetratin conjugation efficiencies could be observed at higher pH values. This effect could be attributed to a higher extent of specific dative binding of the penetratin’s sulfide to the gold nanoparticle surface at increased pH. A simple biological by study revealed a successful uptake of gold-penetratin bioconjugates: within 2 hours, up to 100 % of coincubated cells were loaded with penetratin-conjugated gold nanoparticles

Original Article: Carrier blocks using gold in biomedicine

NEXT ARTICLE

More From BioPortfolio on "Carrier blocks using gold in biomedicine"

Advertisement
Quick Search
Advertisement
Advertisement

 

Relevant Topics

Antibodies
An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples of antigens include microorganisms (such as bacteria, fungi, parasites, and viruses) and chemicals. Antibodies may be produc...

Biotechnology - Biotech
"using living things to create products or to do tasks for humans" About Biotechnology - Biotech Biotechnology is the practice of using plants, animals and micro-organisms such as bacteria, as well as biological processes - such as the ripen...