Plasmonic Nanocages as Photothermal Transducers for Nanobubble Cancer Therapy

I.H. Karampelas, K. Liu, E.P. Furlani
University at Buffalo, SUNY,
United States

Keywords: localized surface plasmon resonance (LSPR), plasmonic nanocages, photothermal energy conversion, LSPR-induced optical absorption, pulsed-laser photothermal heating, photothermal therapy, plasmonic nanobubble cancer treatment


The ability to generate and control thermal energy with nanoscale resolution is finding increasing use in a variety of applications spanning the fields of nanoparticle synthesis, nanofabrication, bio-imaging and medical therapy [1, 2]. One of the most promising approaches to achieving this involves the use of plasmonics, wherein a laser is used to heat metallic nanostructures at their localized surface plasmon resonance (LSPR) wavelength. At plasmon resonance there is a collective and coherent oscillation of electrons within the nanostructures that gives rise to peak absorption of the incident photons and highly localized (sub-wavelength) heating and field enhancement [3]. Continuing on our previous work [4, 5], a series of new computational models is introduced to demonstrate several photonic and thermofluidic details of the photothermal process associated with nanosecond-pulsed, laser-heated gold nanocages. Our work indicates that the unique geometrical characteristics of nanocages offer significant advantages for a variety of photothermal and theranostic applications. Specifically, the LSPR wavelength of a nanocage can be broadly tuned from the visible to the near-infrared (NIR) by controlling its dimensions during synthesis. The ability to tune LSPR to the NIR is especially important for in-vivo applications where the incident light should fall within the NIR “biotransparent” window for more effective tissue penetration. We demonstrate that gold nanocages have a substantial absorption cross-section in the NIR that is essentially independent of orientation. In addition, our thermofluidic analysis indicates that by carefully tuning applied power and pulse duration, the generation of controlled nanobubbles around nanocages is possible without melting the nanoparticle. Hence, gold nanocages could offer immediate and very selective therapeutic options when properly uptaken since explosive nanobubbles can cause immediate lysis of targeted cells while preventing damage to nearby healthy tissue due to strong cooperative heating effects. [1] West, J. L. and Halas N. J. (2000). "Applications of nanotechnology to biotechnology - Commentary." Current Opinion in Biotechnology 11(2): 215-217 [2] Pitsillides, C.M. et. al. (2003). “Selective cell targeting with light-absorbing microparticles and nanoparticles.” Biophysics Journal. 84: 4023-4032. [3] Roper, D.K., W. Ahn, Hoepfner, M. (2007). “Microscale heat transfer transduced by surface plasmon resonant gold nanoparticles.” Journal of Physical Chemistry C 111(9): 3636-3641. [4] Furlani, E.P., Karampelas, I.H. and Xie Q. (2012). “Analysis of pulsed laser plasmon-assisted photothermal heating and bubble generation at the nanoscale.” Lab On A Chip 12: 3707-3719 [5] Alali, F., Karampelas, I.H., Kim Y.H. and Furlani E.P. (2013) “Photonic and Thermofluidic Analysis of Colloidal Plasmonic Nanorings and Nanotori for Pulsed-Laser Photothermal Applications.” Journal of Physical Chemistry C 117: 20178-20185