Tuning Drug Release Profile from Nanoporous Gold Thin Films
- PDF / 213,231 Bytes
- 5 Pages / 432 x 648 pts Page_size
- 78 Downloads / 209 Views
Tuning Drug Release Profile from Nanoporous Gold Thin Films 1
Ozge Kurtulus and Erkin Seker2 Departments of 1Chemical Engineering and Materials Science and 2Electrical and Computer Engineering, University of California - Davis, Davis, CA 95616, USA ABSTRACT Nanoporous gold (np-Au) with its high surface area to volume ratio, tunable pore morphology, ease of surface modification with well-studied thiol chemistry, as well as integration with conventional microfabrication techniques is a promising candidate for controlled drug delivery studies. While it has been demonstrated that np-Au can retain and release drugs, release mechanisms and governing parameters are unclear. This paper reports on the effect of film thickness and morphology on the molecular release from np-Au films. INTRODUCTION Delivering drugs with high spatio-temporal resolution and precise dosage is a major requirement for effective management of disorders. Therefore, there is a need for controlled drug delivery platforms, in which advanced materials play an instrumental role in controlling drug delivery. Recent drug delivery platforms utilize several biomaterials including polymers as eroding templates [1] and inorganic materials as non–eroding templates such as nanoporous anodic aluminum oxide (AAO) and anodic titanium oxide (ATO) [2]. While controlled drug delivery has been established with polymers and ceramics, porous metals, particularly nanoporous gold, has not been explored. Np-Au, which can be produced by dealloying, which consists of selective dissolution of silver from a silver-rich gold alloy, exhibits several advantages such as enabling iontophoretic release of drug molecules and functioning as a highfidelity neural electrode coating [3]. In addition, its tunable properties, such as pore morphology, provide an opportunity to investigate effect of nanoporosity on drug release profile [4]. The objective of this paper is to demonstrate the effect of film thickness and morphology on the loading capacity of np-Au films and consequent release profile of a small-molecule drug surrogate. EXPERIMENTAL DETAILS Fabrication: Nanoporous gold films (3 mm x 3 mm) were patterned on glass coverslips through silicone stencil masks. Prior to film deposition, the coverslips were cleaned for 15 minutes in piranha solution (mixture of hydrogen peroxide and sulfuric acid), rinsed in deionized (DI) water, and dried with nitrogen. Direct-current sputtering system was used to deposit the metal stacks onto the glass coverslips through a laser-cut stencil mask. Following a cleaning step of 50 W Ar plasma treatment, metal films were created by sequential deposition of 15 nm-thick chrome adhesive layer, 50 nm-thick gold seed layer, and co-sputtered Au0.3Ag0.7 alloy layer. By varying the deposition time, we obtained two different film thicknesses – 366 nm and 772 nm. The samples were dealloyed in 65% nitric acid for 15 minutes at 65 °C to produce the nanoporous films. Samples were then rinsed and stored in DI water for a week while changing the water
259
every other d
Data Loading...
