title: Alkaline and ultrasonic dissolution of biological materials for trace silicon determination.
abstract: A simple method for trace elemental determination in biological tissue has been developed. Novel nanomaterials with biomedical applications necessitate the determination of thein vivofate of the materials to understand their toxicological profile. Hollow iron-doped calcined silica nanoshells have been used as a model to demonstrate that potassium hydroxide and bath sonication at 50 °C can extract elements from alkaline-soluble nanomaterials. After alkali digestion, nitric acid is used to adjust thepH into a suitable range for analysis using techniques such as inductively coupled plasma optical emission spectrometry which require neutral or acidic analytes. In chicken liver phantoms injected with the nanoshells, 96% of the expected silicon concentration was detected. This value was in good agreement with the 94% detection efficiency of nanoshells dissolved in aqueous solution as a control for potential sample matrix interference. Nanoshell detection was further confirmed in a mouse 24 h after intravenous administration; the measured silica above baseline was 35 times greater or more than the standard deviations of the measurements. This method provides a simple and accurate means to quantify alkaline-soluble nanomaterials in biological tissue.
authors.affiliation: Department of Nanoengineering, University of California , San Diego, 4112 Pacific Hall, 9500 Gilman Drive 0358, La Jolla, California 92093.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Viveros
authors.affiliation: Materials Science and Engineering Program, University of California , San Diego, 4112 Pacific Hall, 9500 Gilman Drive 0358, La Jolla, California 92093.
authors.forename: Alexander
authors.initials: A
authors.lastname: Liberman
authors.affiliation: Department of Chemistry and Biochemistry, University of California , San Diego, 4100C Pacific Hall, 9500 Gilman Drive 0358, La Jolla, California 92093.
authors.forename: William C
authors.initials: WC
authors.lastname: Trogler
authors.affiliation: Department of Chemistry and Biochemistry, University of California , San Diego, B100E Pacific Hall, 9500 Gilman Drive 0358, La Jolla, California 92093.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Kummel