DNA Adsorption onto Glass Surfaces
Date
2008-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering.
Abstract
Streaming potential measurements were performed on microspheres of silica,
soda lime silicate (SLS) and calcium aluminate (CA) glasses containing silica and iron
oxide (CASi and CAFe). The silicate based glasses exhibited acidic surfaces with
isoelectric points (IEP) around a pH of 3 while the calcium aluminates displayed more
basic surfaces with IEP ranging from 8-9.5. The surface of the calcium aluminate
microspheres containing silica reacted with the background electrolyte, altering the
measured zeta potential values and inhibiting electrolyte flow past the sample at ~ pH 4
due to formation of a solid plug.
DNA adsorption experiments were performed using the microspheres and a
commercially available silicate based DNA isolation filter using a known quantity of
DNA suspended in a chaotropic agent free 0.35 wt% Tris(hydroxymethyl)aminomethane
(Tris) buffer solution. The microspheres and commercial filter were also used to isolate
DNA from macrophage cells in the presence of chaotropic agents. UV absorbance at
~260 nm and gel electrophoresis were used to quantify the amount and size of the DNA
strands that adsorbed to the microsphere surfaces. In both experiments, the 43-106 μm
CAFe microspheres adsorbed the largest quantity of DNA. However, the 43-106 μm
SLS microspheres isolated more DNA from the cells than the <43 μm CAFe
microspheres, indicating that microsphere size contributes to isolation ability.
The UV absorbance of DNA at ~260 nm was slightly altered due to the
dissolution of the calcium aluminate glasses during the adsorption process. Inductively
coupled plasma - optical emission spectroscopy (ICP-OES) determined that calcium and
aluminum ions leached from the CA and CAFe microsphere surfaces during these
experiments. Circular dichroism (CD) spectroscopy showed that the leached ions had no
effect on the conformation of the DNA, and therefore would not be expected to interfere
in downstream applications such as DNA replication.
The 0.35 wt% Tris solution completely inhibited the formation of the hydrated
crystalline layer that develops when the calcium aluminate glassess are incubated in
deionized water. A Tris concentration of 0.24 wt% allowed for the formation of both
hexagonal and cubic hydrates, however they were severely distorted and present in low
amounts such that they were undectable by XRD.
Description
Advisory committee members: William Carty, Lisa Flick, William Lacourse. Dissertation completed in partial fulfillment of the requirements for the degree of Doctorate of Philosophy in Glass Science at the Kazuo Inamori School of Engineering, New York State College of Ceramics at Alfred University
Type
Thesis