Dataset Information

Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency.

ABSTRACT: We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near-infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) make them suitable for photothermal therapy as demonstrated by tumor cell annihilation upon laser irradiation. The otherwise harmless nature of these NCs in dark conditions was confirmed by in vitro toxicity tests on two different cell lines. The presence of the deep Fe levels constituting the IB is the origin of such enhanced PTE, which can be used to design other high performing NC photothermal agents.

SUBMITTER: Ghosh S

PROVIDER: S-EPMC5634747 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Colloidal CuFeS<sub>2</sub> Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency.

Ghosh Sandeep S Avellini Tommaso T Petrelli Alessia A Kriegel Ilka I Gaspari Roberto R Almeida Guilherme G Bertoni Giovanni G Cavalli Andrea A Scotognella Francesco F Pellegrino Teresa T Manna Liberato L

Chemistry of materials : a publication of the American Chemical Society 20160602 13

We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS<sub>2</sub>). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near-infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. ...[more]

PMID: 29033496

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Project description:Rationale: Chemodynamic therapy (CDT) based on the Fe(II)-mediated Fenton reaction is an emerging tumor treatment strategy. However, the catalytic efficiency in tumors is crucially limited by Fe(II). Herein, an endogenous hydrogen sulfide (H2S) accelerated Fe(III)/Fe(II) transformation and photothermal synergistically enhanced CDT strategy based on ellagic acid-Fe-bovine serum albumin (EA-Fe@BSA) nanoparticles (NPs) was developed for colon tumor inhibition. On the one hand, the Fe(III) with low catalytic activity in the EA-Fe@BSA NPs could be rapidly reduced to the highly active Fe(II) by the abundant H2S in colon cancer tissues. Thus, a rapid Fe(III)/Fe(II) conversion system was established, wherein highly active Fe(II) ions were continuously regenerated to improve the CDT efficiency. On the other hand, the photothermal effect of EA-Fe@BSA NPs also accelerated the production of hydroxyl radicals (•OH), thereby synergistically enhancing the CDT performance and improving the therapeutic efficacy. Methods: The endogenous H2S accelerated Fe(III)/Fe(II) conversion and PTT enhanced CDT were investigated by characterization of the Fe valence state and detection of •OH. T 1-weighted magnetic resonance imaging (MRI) was tested both in vitro and in vivo. The biocompatibility of NPs were examined via MTT assay, hemolysis analysis and routine blood measurements. The enhanced CDT was investigated in HCT116 colon cancer cells by Calcein-AM/PI staining and MTT assay, and tumor inhibition was demonstrated in HCT116 tumor bearing mice. Results: In this work, EA-Fe@BSA NPs were constructed as a CDT theranostic reagent. The H2S accelerated Fe(III)/Fe(II) conversion was confirmed, more degradation of MB and generation of •OH demonstrated the enhanced CDT in vitro. EA-Fe@BSA NPs exhibited good T 1-weighted MRI performance. More importantly, it displayed strong near-infrared (NIR) absorption and excellent photothermal efficiency, further promotes the production of •OH. Hence, the efficacy of CDT was enhanced, and the tumor growth was inhibited efficiently. Conclusion: All results demonstrate that this strategy based on endogenous H2S promoted Fe(III)/Fe(II) transformation together with PTT acceleration permits efficient Fenton-reaction- mediated CDT both in vitro and in vivo, which holds great potential for effective colon cancer theranostics.

Dataset Information

Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency.

Publications

Colloidal CuFeS<sub>2</sub> Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency.

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