Synthesis method‐dependent photothermal effects of colloidal solutions of platinum nanoparticles used in photothermal anticancer therapy

Abstract

One of the most common anticancer therapies is photothermal therapy (PTT). The effectiveness of PTT depends on the photosensitizer being a molecule which is toxic for the cancer cells after electromagnetic wave irradiation. Therefore, a simulation of PTT was performed in this work on two colon cancer cells (SW480 and SW620) using platinum nanoparticles (Pt NPs). Interestingly, in the literature the dependence between the synthesis method and the photothermal properties of Pt NPs was not discussed. Consequently, in this paper, we evaluated the photothermal properties of Pt NPs synthesized by two different methods: polyol (PtI NPs) and green chemistry (PtII NPs). Scanning transmission electron microscopy revealed that the size of both Pt NPs obtained was 2 nm, the NPs were not agglomerated, and that the PtII NPs were distributed on green tea supports. The selected area electron diffraction and X‐ray diffraction analysis confirmed the crystallinity of both types of Pt NPs. Fourier‐transform infrared (FTIR) spectrum of the PtII NPs showed interactions between the NPs and stretching modes for C=O groups from flavonoids and polyphenols. Therefore, these chemical compounds could be responsible for reducing Pt4+ ions to Pt0. Moreover, the 3‐(4,5‐dimethylthiazol‐2‐yl)‐5‐(3‐carboxymethoxyphenyl)‐2‐(4‐sulfophenyl)‐2H‐tetrazolium (MTS) assay showed that the PtII NPs exhibited 10% and 20% better cytotoxicity effect on SW480 and SW620 cells, than PtI NPs. The viability of cancer cells decreased when Pt NPs were used in PTT. The highest percentage of dead cells (82%) was observed for PtII NPs and 650‐nm laser irradiation. FTIR and Raman spectroscopy showed structural changes induced by both Pt NPs and laser irradiation of cells in the range corresponding to levels of DNA, phospholipids, proteins, and lipids. Moreover, the calculated photothermal conversion efficiency showed that the value of this parameter is around 35%, regardless of the synthesis method and used wavelengths.

Platinum Nanoparticles: Green Synthesis and Biomedical Applications

“…While the % viability for cancer cells cultured with PtNPs and irradiated with 808 nm laser was 25% and 22% for SW480 and SW620, respectively. These findings may support future applications of biosynthesized PtNPs in photothermal cancer therapy [73]. Dobrucka et al reported the green synthesis of spherical and hexagonal PtNPs (4 nm) employing Ononis spinosa radix extract.…”

Cichorium intybus Leaves Extract in Varying Solvent Systems for the Production of Platinum Nanoparticles: Design and Development of a Green Approach

“…In addition to being crucial for the production and application of PtNPs, the development of simple and environmentally friendly synthesis techniques also support the growing eld of green chemistry [21]. According to previous literature platinum nanoparticles were synthesized by using plant extracts Atriplex halimus [12], green tea powder [22], Saudi dates extract [23], Xanthium strumarium [24] Punica granatum [25], Nigella sativa L.[26], Antigonon leptopus [27], Garcinia mangostana L. [28], orange peel [29] etc. These plant extracts are made up of several distinct ingredients.…”

Improving the Effect of Cancer Cells Irradiation with X-rays and High-Energy Protons Using Bimetallic Palladium-Platinum Nanoparticles with Various Nanostructures

“…Various mechanisms (physical, chemical-biological, or biological) are involved in radiosensitization; these mechanisms can overlap or act individually, depending, for example, on the type or energy of radiation [ 13 , 14 ]. The final effect of radiosensitization by NPs depends on the type of metal used, its size, shape, and the method of synthesis [ 15 , 16 , 17 , 18 ]. Exemplary, the generation of ROS by cells under the influence of NPs has already been known in the literature, e.g., for the widely used gold nanoparticles [ 19 ].…”