The inherent ability of gold nanoparticles (AuNPs) to transduce light energy into heat, coupled with their ease of bioconjugation has made them a powerful tool potentially capable of controlling biological activity. When combined with ultra-short pulses of light and the proper experimental conditions, AuNPs are capable of heating their local environment without increasing the bulk solution temperature. Gene therapy and siRNA delivery have emerged as promising applications for localized heating of AuNPs and as such, a number of different groups have used light to trigger the release of nucleic acids from the surface of AuNPs. While successful nucleic acid release is universally demonstrated in the literature, the mechanism of release varies between reports. Specifically, the reported release mechanism is either: 1) the thermal denaturing of a nucleic acid duplex and release of a “single stranded” nucleic acid into solution; 2) the cleavage of the prototypical gold-thiol bond used to tether the nucleic acid duplex to the surface, resulting in the release of the complete nucleic acid duplex; or 3) a combination of both. Due to the complex parameter space in these experimental systems (AuNP size/shape/composition, laser energy density/repetition rate/pulse width) it is not surprising that the reported release mechanisms differ. Here, we utilize examples from the literature in order to identify the key parameters that dictate the release mechanism of nucleic acids on AuNPs in an attempt to further a comprehensive understanding of this process.
The development of dynamic DNA nanostructures has opened the door to a wide variety of applications including sensing and information processing. DNA based molecular logic devices (MLDs) are DNA structures that have the ability to sense multiple inputs or “targets”, autonomously process the absence or presence of targets, and provide an output signal indicating the logic state of the system. As DNA is readily functionalized with fluorescent molecules, fluorophores can be strategically placed on MLDs so that the Förster resonance energy transfer efficiencies between the fluorophores are modulated when the DNA structure undergoes rearrangement. Consequently, the fluorescent signal of the dyes can be used as an output that provides the current logic state of the system. Although still in their elementary phase, MLDs have proved to be a promising modality for sensing multiple nanoscale targets, especially nucleic acids. Here, we review the development of multifluorophore MLDs and utilize examples from the literature and our own work to highlight their potential capabilities.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.