A histological evaluation and in vivo assessment of intratumoral near infrared photothermal nanotherapy-induced tumor regression

Abstract

Purpose Nanoparticle (NP)-enabled near infrared (NIR) photothermal therapy has realized limited success in in vivo studies as a potential localized cancer therapy. This is primarily due to a lack of successful methods that can prevent NP uptake by the reticuloendothelial system, especially the liver and kidney, and deliver sufficient quantities of intravenously injected NPs to the tumor site. Histological evaluation of photothermal therapy-induced tumor regression is also neglected in the current literature. This report demonstrates and histologically evaluates the in vivo potential of NIR photothermal therapy by circumventing the challenges of intravenous NP delivery and tumor targeting found in other photothermal therapy studies. Methods Subcutaneous Cal 27 squamous cell carcinoma xenografts received photothermal nanotherapy treatments, radial injections of polyethylene glycol (PEG)-ylated gold nanorods and one NIR 785 nm laser irradiation for 10 minutes at 9.5 W/cm 2 . Tumor response was measured for 10–15 days, gross changes in tumor size were evaluated, and the remaining tumors or scar tissues were excised and histologically analyzed. Results The single treatment of intratumoral nanorod injections followed by a 10 minute NIR laser treatment also known as photothermal nanotherapy, resulted in ~100% tumor regression in ~90% of treated tumors, which was statistically significant in a comparison to the average of all three control groups over time ( P <0.01). Conclusion Photothermal nanotherapy, or intratumoral nanorod injections followed by NIR laser irradiation of tumors and tumor margins, demonstrate the potential of NIR photothermal therapy as a viable localized treatment approach for primary and early stage tumors, and prevents NP uptake by the reticuloendothelial system.

Gold Nanoprism–Nanorod Face Off: Comparing the Heating Efficiency, Cellular Internalization and Thermoablation Capacity

“…The ability of nanomaterials to convert light energy into heat, the photothermal effect, is a characteristic and versatile property applicable to many biomedical applications including photothermal therapy [1][2][3], drug delivery [4][5][6], optoacoustic imaging [7,8] and biosensing [9], among others [10]. The photothermal treatment of solid tumours by thermoablation has reached the stage of clinical trials [11].…”

In-vitro depth-dependent hyperthermia of human mammary gland adenocarcinoma

“…[1][2][3][4] Hyperthermia provides a method of non-invasive treatment for solid state tumors requiring only direct or local intravenous injection. [5][6][7] Magnetite (Fe 3 O 4 ) nanoparticles induce local hyperthermia when subject to a near infrared (NIR) optical source. 1,8,9 This hyperthermic effect alone may provide the required thermal energy to ablate local tissue but also may act as a triggering mechanism for release of chemotherapeutics trapped within a polymer matrix surrounding the nanoparticles, 5,8,10 and provide a protective to attenuate the toxicity of uncoated magnetite 11,12 .…”

Effects of arginine&ndash;glycine&ndash;aspartic acid peptide-conjugated quantum dots-induced photodynamic therapy on pancreatic carcinoma in vivo

“…Furthermore, more QDs-RGD would approach tumors compared with conventional intravenous injection. [35][36][37] Upon subsequent PDT, the irradiation procedure was another parameter to be re-evaluated. If the procedure of laser light illumination was conducted much closer to the tumor cells (eg, in the tumor mass), the PDT effect might be better than the irradiation method used previously.…”