Ghosh Sandeep, Avellini Tommaso, Petrelli Alessia, Kriegel Ilka, Gaspari Roberto, Almeida Guilherme, Bertoni Giovanni, Cavalli Andrea, Scotognella Francesco, Pellegrino Teresa, Manna Liberato
Department of Nanochemistry, CompuNet, and Department of Drug Discovery and Development, Istituto Italiano di Tecnologia (IIT), via Morego 30, 16163 Genova, Italy.
Dipartimento di Chimica e Chimica Industriale, Università degli Studi di Genova, Via Dodecaneso, 31, 16146 Genova, Italy.
Chem Mater. 2016 Jul 12;28(13):4848-4858. doi: 10.1021/acs.chemmater.6b02192. Epub 2016 Jun 2.
We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS). 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 CuFeS 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.
我们描述了一种高丰度矿物黄铜矿（CuFeS₂）的相纯纳米晶体（NCs）的胶体热注入合成法。以480和950纳米左右为中心的吸收带，几乎涵盖了整个可见光和近红外区域，体现了它们的光学消光特性。这些峰归因于从价带（VB）到位于基本能隙中且主要由Fe 3d轨道组成的空中间带（IB）的电子跃迁。对CuFeS₂ NCs水悬浮液进行激光照射（808纳米）显示出显著的加热效果，光热转换效率为49%。这种高效加热归因于在宽中间带（由于间接的价带 - 中间带能隙）内的载流子弛豫，瞬态吸收测量证实了这一点。这些NCs在所谓的生物窗口（650 - 900纳米）中的强烈吸收和高光热转换效率（PTE）使其适用于光热疗法，激光照射后肿瘤细胞的消除证明了这一点。通过对两种不同细胞系的体外毒性测试证实了这些NCs在黑暗条件下原本无害的性质。构成中间带的深铁能级的存在是这种增强的光热转换效率的根源，这可用于设计其他高性能的NC光热剂。
