Colloidal gold particles preparation

Muhlpfordt, J. A. (1982) The preparation of colloidal gold particles using tannic acid as an additional reducing agent. Experientia 38, 1127-1128. 

Kameo A, Suzuki A, Torigoe K, Esumi K (2001) Fiber-like Gold Particles Prepared in Cationic Micelles by UV Irradiation Effect of Alkyl Chain Length of Cationic Surfactant on Particle Size. J Colloid Interface Sci 241 89-292... 

Fig. 1. Formvar grid coated with a colloidal suspension of 14-nm gold particles prepared using the method of Slot and Geuze (4). Most gold particles are spherical singlets, duplets, or triplets (g). Occasionally, the particles are tetrahedral (t) or in clusters (c). Electron micrograph ><125,000.

It has been reported that some commercial preparations of colloidal gold-antibody complexes may contain free active antibody. Such free antibody will compete with antibody-colloidal gold particles for antigen binding sites and may reduce labeling intensity. The presence of free protein may be identified using a simple test procedure (20)... 

Although some colloids settle out into two separate phases if left standing long enough, others persist indefinitely a suspension of gold particles prepared by... 

A. Henglein, Radiolytic Preparation of Ultrafine Colloidal Gold Particles in Aqueous Solution Optical Spectrum, Controlled Growth, and Some Chemical Reactions. Langmuir 1998,... 

Gold colloids were prepared by controlled reduction of gold chloride with sodium citrate using the procedure described by Frens (15). The strength of color showing was closely related to the size and quality of the colloidal gold particles. The size of the colloidal gold particles was directly dependent on the amount of trisodium citrate used in its preparation process. The results were summarized in Table 2. 

Colloidal gold particles were prepared by the reduction of chloroauric acid with citric acid or phosphoric acid. Following conjugation at pH 9 with affinity purified antibodies, the colloidal... 

Developing the sol immobilisation technique described in Section 13.2 and increasing our ability in preparing small colloidal gold particles, we were able to implement the activity of the gold catalyst from a few hundred TOP units up to 3500 h" in the case of glycolate and 2000 h in the case of lactate. Selectivity data, evaluated at 100% conversion, were exceptionally high, whereas a lower selectivity was observed in the case of Pd and Pt catalysts. 

Colloidal gold was first made in the 1600s for use in microscopy. Colloidal gold particles are excellent markers in electron microscopy because they are electron-dense, spherical in shape, and can be prepared in sizes from 1 to 25 run. Colloidal gold (10 mn) is a useful tracer to obtain information about the processes involved in the immunological response. 

Antibodies are prepared according to our published method (7) Two distinct permutations are available the antigen may either be attached to colloidal gold particles, or immunization may be by conventional means. If the latter, simpler approach is used, the titer is always lower, though still acceptable. 

Colloidal systems can be divided into lyophilic and lyophobic systems. Lyophilic colloids have a strong affinity with the dispersion medium by which a solvation shell around the particle is formed. This process is called solvation and if the dispersion medium is water it is called hydration. A polysaccharide dissolved in water is an example of a lyophilic colloidal system. The solvation shell is formed by hydrogen bonds between the hydroxyl groups of the polymer molecules and the water molecules. Pharmaceutical examples are solutions of dextran, used as plasma expanders. Micelles are also lyophilic colloids. Example of such a system is the aqueous cholecalciferol oral mixture (Table 18.15). In these preparations, a lipophilic fluid is dissolved in an aqueous medium by incorporating it in micelles. Because this type of colloids falls apart on dilution to concentrations below the CMC, they are also known as association colloids. Lyophobic colloids have no affinity with the dispersion medium. Thus, in this type of colloids no solvation shell is formed around the particles. An example of lyophobic particles are colloidal gold particles (with a diameter of 1 nm - 1 pm) dispersed in water. There are no... 

A. Kameo et al., Fiber-like gold particles prepared in cationic micelles by UV irradiation effect of alkyl chain length of cationic surfactant on particle size. Journal of Colloid and Interface Science, 241,289-292 (2001). 

A. Henglein, Radiolytic preparation of ultrafine colloidal gold particles in aqueous solution optical spectrum, controlled growth, and some chemical reactions, Langmuir 15,6738-6744 (1999). 

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