We used the modified technique previously described by Savion et al.,
6 which we used previously to measure silicone oil emulsification.
5 Six different silicone oil blends (500 μL) along with 500-μL emulsifier (Pluronic 10%, plasma, or serum) were pipetted into a glass cuvette (inner dimension 4 × 10 × 40 mm). Plasma and serum were collected from one individual on a single day. They were kept frozen at −80°C until use. Informed consent was provided from the individual, and the procedure adhered to the declaration of Helsinki. We have previously published this method.
5 We repeated the experiments, and the results published here were performed with other plasma and serum samples (i.e., not the same samples reviewed in the previous paper).
5 The glass cuvette was then put into a water-filled sonication device (Sonorex TK 30, Bandelin Electronic, Berlin, Germany) for 3 minutes. The water temperature was kept at 20°C to 24°C. The entire system was then centrifuged at 5000
g for 30 minutes. After centrifugation, the nonemulsified oil was on top, followed by emulsified oil in the middle and the aqueous solution at bottom. The glass cuvette was then photographically documented. Each oil blend was tested four times.
The area of the emulsified oil was measured using ImageJ software (developed by Wayne Rasband, National Institutes of Health, Bethesda, MD; available at
http://rsb.info.nih.gov/ij/index.html). The area of emulsified oil was presented as area in percent (i.e., area of emulsified oil (%) = (area of emulsified oil × 100%)/(area of nonemulsified oil + area of emulsified oil + area of aqueous solution). Statistical analysis was performed using the number cruncher statistical system (version 2004; NCSS, Kaysville, UT). All data are presented as mean ± SD.
P < 0.05 was considered statistically significant.