(542d) Gold Nanocones: A Candidate for Cavitation-Enhanced Drug Delivery

Title: Gold Nanocones: A Candidate for
Cavitation-Enhanced Drug Delivery

Authors: Xiaoqian Su and James J. Kwan

Ultrasound is a high
frequency longitudinal pressure wave. With sufficient energy, ultrasound is
capable of nucleating cavitation: the dynamic oscillations of a gas or vapour
cavity. Cavitation promotes a multitude of mechanical effects, including,
jetting, shockwaves, and microstreaming. These mechanical effects have been established
to be key mechanisms in ultrasound-enhanced the delivery of therapeutics for a
broad range of clinical applications such as cancer therapy. However, the
nucleation of cavitation with ultrasound alone requires energies that are
damaging to surrounding tissue. Therefore to remove off target damage,
particles that generate cavitation, i.e., cavitation agents, are required.

Conventional
cavitation agents, i.e., ultrasound contrast agents, have demonstrated the
ability to enhance drug delivery. Yet the potential for enhanced therapy from
these particles in certain therapies are limited because of their large size
and rapid acoustic destruction short lifetime. We have previously demonstrated
that the use of a single cavity polymeric nanoparticles that trap nanobubbles,
provide sustained cavitation, and improved cancer drug delivery¹. However,
the acoustic energy requirements to nucleate sufficient cavitation was
substantial. Here, we show an effective method to manufacture gold nanocone
cavitation agents. Furthermore, the unique structure of the gold
nanocones enables the formation of clustered bellflower super structures with
multiple cavities, which will reduce the acoustic energy requirements for
cavitation. To measure the acoustic responses of these novel cavitation agents,
we expose these particles to increasing pressure amplitudes until cavitation is
observed with a passive cavitation detector. The result here will aid in the
design and manufacture of the next generation ultrasound-responsive
nanoparticles for ultrasound-enhanced drug delivery.

1     Kwan,
J. J. et al. Ultrasound©\Propelled
Nanocups for Drug Delivery. small 11, 5305-5314 (2015)

Keywords:
ultrasound, drug delivery, cavitation, nanoparticles