Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent
Abstract Although plasmonic palladium (Pd) nanospheres are thermodynamically stable and have high photothermal conversion due to the free and bound electron coupling associated with the intrinsic high interband transition, they have not attracted attention as a photothermal conversion material for n...
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| Format: | Article |
| Language: | English |
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SpringerOpen
2022-06-01
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| Series: | Nanoscale Research Letters |
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| Online Access: | https://doi.org/10.1186/s11671-022-03697-1 |
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| author | Yutaro Hayakawa Masato Furuya Hironobu Tahara Yasuhiro Kosuge Tsuyoshi Kimura Kosuke Sugawa Joe Otsuki |
| author_facet | Yutaro Hayakawa Masato Furuya Hironobu Tahara Yasuhiro Kosuge Tsuyoshi Kimura Kosuke Sugawa Joe Otsuki |
| author_sort | Yutaro Hayakawa |
| collection | DOAJ |
| description | Abstract Although plasmonic palladium (Pd) nanospheres are thermodynamically stable and have high photothermal conversion due to the free and bound electron coupling associated with the intrinsic high interband transition, they have not attracted attention as a photothermal conversion material for next-generation photothermal cancer therapy. This is because the Pd nanospheres generate the localized surface plasmon resonance (LSPR) intrinsically in the ultraviolet region, which is far away from the biological transparent window (750–900 nm). In this study, we controlled the LSP wavelength of Pd nanospheres by coating with high refractive index TiO2 shells taking advantage of the Pd LSPR which is highly sensitive to changes in the local refractive index around the nanospheres. Our calculations indicated that the absorption cross section at 808 nm (corresponding to the wavelength used for photothermal treatment) was increased by 4.5 times by redshifting the LSPR and increasing the extinction intensity associated with the coating with TiO2 shell. Experiments confirmed the theoretical prediction in that the LSPR of the synthesized Pd nanospheres with a diameter of 81 nm was significantly redshifted by coating with amorphous TiO2 shell, resulting in significant large extinction intensity at 808 nm. The photothermal conversion efficiency was estimated to be 50%. In vitro cell tests, HeLa cells incubated with 100–300 μg/mL TiO2-coated Pd nanospheres were efficiently killed by irradiating 808 nm laser (1.8 W) even though the nanospheres with the same concentrations showed little cytotoxicity. These results indicate that the Pd nanospheres coated with high refractive index shells can be promising as a photothermal therapy agent. |
| first_indexed | 2024-03-12T18:04:37Z |
| format | Article |
| id | doaj.art-988a515400b44d1eabb5fa663404a246 |
| institution | Directory Open Access Journal |
| issn | 1556-276X |
| language | English |
| last_indexed | 2024-03-12T18:04:37Z |
| publishDate | 2022-06-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Nanoscale Research Letters |
| spelling | doaj.art-988a515400b44d1eabb5fa663404a2462023-08-02T09:31:02ZengSpringerOpenNanoscale Research Letters1556-276X2022-06-0117111310.1186/s11671-022-03697-1Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy AgentYutaro Hayakawa0Masato Furuya1Hironobu Tahara2Yasuhiro Kosuge3Tsuyoshi Kimura4Kosuke Sugawa5Joe Otsuki6Department of Materials and Applied Chemistry, College of Science and Technology, Nihon UniversityDepartment of Materials and Applied Chemistry, College of Science and Technology, Nihon UniversityGraduate School of Engineering, Nagasaki UniversityLaboratory of Pharmacology, School of Pharmacy, Nihon UniversityInstitute of Biomaterials and Bioengineering, Tokyo Medical and Dental UniversityDepartment of Materials and Applied Chemistry, College of Science and Technology, Nihon UniversityDepartment of Materials and Applied Chemistry, College of Science and Technology, Nihon UniversityAbstract Although plasmonic palladium (Pd) nanospheres are thermodynamically stable and have high photothermal conversion due to the free and bound electron coupling associated with the intrinsic high interband transition, they have not attracted attention as a photothermal conversion material for next-generation photothermal cancer therapy. This is because the Pd nanospheres generate the localized surface plasmon resonance (LSPR) intrinsically in the ultraviolet region, which is far away from the biological transparent window (750–900 nm). In this study, we controlled the LSP wavelength of Pd nanospheres by coating with high refractive index TiO2 shells taking advantage of the Pd LSPR which is highly sensitive to changes in the local refractive index around the nanospheres. Our calculations indicated that the absorption cross section at 808 nm (corresponding to the wavelength used for photothermal treatment) was increased by 4.5 times by redshifting the LSPR and increasing the extinction intensity associated with the coating with TiO2 shell. Experiments confirmed the theoretical prediction in that the LSPR of the synthesized Pd nanospheres with a diameter of 81 nm was significantly redshifted by coating with amorphous TiO2 shell, resulting in significant large extinction intensity at 808 nm. The photothermal conversion efficiency was estimated to be 50%. In vitro cell tests, HeLa cells incubated with 100–300 μg/mL TiO2-coated Pd nanospheres were efficiently killed by irradiating 808 nm laser (1.8 W) even though the nanospheres with the same concentrations showed little cytotoxicity. These results indicate that the Pd nanospheres coated with high refractive index shells can be promising as a photothermal therapy agent.https://doi.org/10.1186/s11671-022-03697-1Localized surface plasmon resonancePalladium nanospheresPhotothermal therapyPhotothermal conversionTitanium dioxide |
| spellingShingle | Yutaro Hayakawa Masato Furuya Hironobu Tahara Yasuhiro Kosuge Tsuyoshi Kimura Kosuke Sugawa Joe Otsuki Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent Nanoscale Research Letters Localized surface plasmon resonance Palladium nanospheres Photothermal therapy Photothermal conversion Titanium dioxide |
| title | Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent |
| title_full | Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent |
| title_fullStr | Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent |
| title_full_unstemmed | Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent |
| title_short | Modulation Technique of Localized Surface Plasmon Resonance of Palladium Nanospheres by Coating with Titanium Dioxide Shell for Application to Photothermal Therapy Agent |
| title_sort | modulation technique of localized surface plasmon resonance of palladium nanospheres by coating with titanium dioxide shell for application to photothermal therapy agent |
| topic | Localized surface plasmon resonance Palladium nanospheres Photothermal therapy Photothermal conversion Titanium dioxide |
| url | https://doi.org/10.1186/s11671-022-03697-1 |
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