The goal of clinical research is to develop generalizable knowledge that improves human health or increases understanding of human biology. The path to finding if a new drug or treatment is safe or effective, for example, is to test it on patient volunteers. People who participate in clinical research make it possible to secure that knowledge. Ethical criteria must however guide the provision of such interventions. These include transparency about all aspects of care, informed consent, freedom of choice, confidentiality, respect for the person, preservation of dignity and involvement of the community. The purpose of ethical guidelines is both to protect patient volunteers and to preserve the integrity of the science.
nanoparticles. 1mL of the nanoparticles were diluted with 20mL of water, and the pH of this solution adjusted to 8.5 by ammonia, of 30% by weight. 20l of 10mg mL-1 poly (allylamine hydrochloride) was added to the mixture before purification involving a magnetic field and water, as previously described. This resulted in poly (allylamine hydrochloride) coated nanoparticles, which were suspended in 20mL of water.
The penultimate step was the addition of a coating of gold seeds to the poly (allylamine hydrochloride) coated nanoparticles, by combining 20mL of the “bare” gold nanoparticles from the first step with 20mL of the poly (allylamine hydrochloride) coated-nanoparticles in an ice bath. Again, purification was achieved with a magnetic field and water. The nanoparticles were then suspended in 20mL of water with 5mg of thiolated polyethylene glycol, and again washed with water before being suspended in 40mL of water.
The final stage was the formation of the gold shell, where 50L of 1.0% by weight chloroauric acid was added to the thiolated PEG-modified nanoparticles, followed by 100L of 80mM hydroxylamine. Again, a magnetic field and water were used to separate the nanoparticles before suspending them in 20mL of water with a further 5mg of polyethylene glycol, and another purification step involving a magnetic field and water was carried out. The steps involving the formation of the gold shell were repeated three times in order to achieve a full coverage of the nanoparticle.10
Of all the methods discussed until this point, this is by far the most complex in terms of the number of steps, and the variety of materials used. This is due to the number of layers involved in the nanoparticles – magnetite nanoparticles, a poly (allylamine hydrochloride) coating, a thiolated PEG coating, and a gold shell. This is also a very costly procedure, not just due to the number of reagents but because several reagents are individually expensive – chloroauric acid, polyethylene glycol, ammonia, poly (allylamine hydrochloride), thiolated PEG, and hydroxylamine in particular. It was again assumed that the highest purity of each reagent would be desired given the potential biological application.
However, despite the disadvantages in the synthesis of these nanoparticles, the end product stan
