Nanoparticles for photothermal therapies

Abstract

The current status of the use of nanoparticles for photothermal treatments is reviewed in detail. The different families of heating nanoparticles are described paying special attention to the physical mechanisms at the root of the light-to-heat conversion processes. The heating efficiencies and spectral working ranges are listed and compared. The most important results obtained in both in vivo and in vitro nanoparticle assisted photothermal treatments are summarized. The advantages and disadvantages of the different heating nanoparticles are discussed.

Neodymium‐Based Stoichiometric Ultrasmall Nanoparticles for Multifunctional Deep‐Tissue Photothermal Therapy

“…[16] Previous studies have concluded that, while Nd:NPs display the already mentioned interesting properties (such as superior spectral and physical stabilities), they also present the disadvantage of a relatively low absorption cross section per NP, which results in a nonefficient absorption of optical excitation radiation. [3] Such reduced absorption cross section stems from the intrinsic low absorption probabilities characteristic of Nd 3+ ions as well as from the typically low content of Nd 3+ ions per RENP (usually below 10 mol.%). This limitation can be partially overcome by increasing the doping level, i.e., the content of rare earth ions per NP, as it would lead to an overall increase in the RENPs absorption cross section.…”

“…NP-PTTs have already been used for in vivo cancer treatment in animal models with remarkable success. [3] Although a great variety of nanostructures, ranging from gold NPs to carbon-based nanomaterials and even organic NPs, have been used as photothermal agents, the research on novel heating NPs capable of overcoming the actual limitations of NP-PTT is a hot area involving a large scientific community. [4] One of the most important limitations of photothermal therapy is the light absorption and scattering of biological tissues, which results in a reduced penetration depth of the optical excitation radiation required for sub-tissue heat generation.…”

Controllable Cobalt Oxide/Au Hierarchically Nanostructured Electrode for Nonenzymatic Glucose Sensing

“…For example, it has been reported that silica-gold core-shell nanoparticles (150 nm diameter) had total extinctions that are comprised of only 15% absorption efficiency [215]. Shells also have broadened spectral line widths due to variation in size and shape within an ensemble and are considered cytotoxic due to the polymer core [190,216]. Rods, cubes, stars and aggregates, as noted earlier, will have reduced overlap with incident light because they have two or more resonances [18,35,48,55].…”

“…Photothermal ablation (PTA) is an attractive alternative to chemotherapy and invasive surgery for treating a variety of cancers and a number of excellent reviews have been published on the topic [5,53,119,167,[185][186][187][188][189][190]. Briefly, noble metal nanoparticles, exhibiting NIR absorption in the appropriate size regime (20-100 nm) for biological applications, are modified with either an antibody or ligand specific to an antigen or receptor, on the surface of a tumor cell [38,53,190].…”

“…Briefly, noble metal nanoparticles, exhibiting NIR absorption in the appropriate size regime (20-100 nm) for biological applications, are modified with either an antibody or ligand specific to an antigen or receptor, on the surface of a tumor cell [38,53,190]. NIR absorbing particles are preferred since it is well known that blood and tissue are most readily penetrated by light in this wavelength region [191][192][193].…”