Posts Tagged ‘patent’
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January 11th, 2010
Patenting nanotechnologies
I’m a big fan of the nano patents and innovations blog, and they have kicked off the year with an eye-opening post regarding the sheer volume of patent activity in the field of nanotechnology. In the first week of 2010, approximately 102 nano-related patents were identified, many filed by some of the world’s leading names including Sony, Samsung, Roche and Pfizer.
The blog author determined that the majority of these patents are devoted to nanomaterials and nanofabrication processes for the semiconductor industry. However, biomedical applications were also well represented. Gold is a prominent material in both of these areas, more details of which can be found on our scientific website
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March 2nd, 2009
New patent on Colloidal Gold Production
Colloidal gold is routinely manufactured by many precious metal companies by a process based on the ancient Purple of Cassius route (see L B Hunt, Gold Bull, 9 (4), 24-31, 1976) but with process improvements to give more consistent processes and products. For example, it is used to produce colloidal gold pink enamels for the decoration of pottery and as biomedical diagnostic agents.
The classic Gold Bulletin papers by Turkevich (Gold Bull, 18 (3) 86-91 and 18 (4), 125-131, 1985) describe the process chemistry and properties of the colloids produced. Properties are dependent on colloid particle size but a problem is that it is difficult to produce colloids to a defined particole size in practice at the commercial scale.
Aimed at use as an in-vitro diagnostic agent with improved sensitivity and reliability, a new European patent application from Tanaka KK, Japan, EP2027956 (A1), was published on 25th February 2009. This is aimed at producing gold colloids with a targeted particle size, a sharp size distribution and a uniform, perfectly spherical shape. This process differs from the traditional ones in that it comprises several steps: a nucleation step and one or more subsequent growth steps, each of which involves additions of gold salt solution and reducing agent to the original nucleation solution. In the nucleation stage, a citrate is used as the reducing agent, whereas an ascorbate is used in the growth stages as the reducing agent. The number of growth steps controls the size of colloidal particle attained. The amount of gold salt and ascorbate added in each of the growth stages is defined in terms of a formula related to the number of gold atoms deposited. This method is claimed to produce spherical gold colloids in the size range of about 17 – 220nm plus with a particle size distribution having a standard deviation of 10% or less.
It would be interesting to see how this multi-step approach might be applied to gold catalyst production where nanosized gold particles of tightly controlled size are critical to catalyst performance.
Trevor Keel
Chris Corti
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