Exploiting Co Defects in CoFe-Layered Double Hydroxide (CoFe-LDH) Derivatives for Highly Efficient Photothermal Cancer Therapy

Abstract

Currently, two-dimensional materials are being actively pursued in catalysis and other fields due their abundance of defects, which results in enhanced performance relative to their bulk defect-free counterparts. To date, the exploitation of defects in two-dimensional materials to enhance photothermal therapies has received little attention, motivating a detailed investigation. Herein, we successfully fabricated a series of novel CoFe-based photothermal agents (CoFe-x) by heating CoFe-layered double hydroxide (CoFe-LDH) nanosheets at different temperatures (x) between 200–800 °C under a Ar atmosphere. The CoFe-x products differed in their particle size, cobalt defect concentration, and electronic structure, with the CoFe-500 product containing the highest concentration of Co2+ defects and most efficient photothermal performance under near-infrared (NIR, 808 nm) irradiation. Experiments and density functional theory (DFT) calculations revealed that Co2+ defects modify the electronic structure of CoFe-x, narrowing the band gap and thus increasing the nonradiative recombination rate, thereby improving the NIR-driven photothermal properties. In vitro and in vivo results demonstrated that CoFe-500 was an efficient agent for photothermal cancer treatment and also near-infrared (NIR) thermal imaging, magnetic resonance (MR) imaging, and photoacoustic (PA) imaging. This work provides valuable new insights about the role of defects in the rational design of nanoagents with optimized structures for improved cancer therapy.

Electrodeposition of Defect‐Rich Ternary NiCoFe Layered Double Hydroxides: Fine Modulation of Co3+ for Highly Efficient Oxygen Evolution Reaction

“…[18,19] Furthermore, discontinuous lattice was observed for Ni(Co 0.5 Fe 0.5 )/NF, indicating the existence of atomic vacancies and defect sites. [23,24] In order to evaluate the electrocatalytic OER performance of the as-prepared Ni(Co 0.5 Fe 0.5 ) LDHs, a typical three-electrode system in an O 2 -saturated 1 M KOH was applied. All potentials referred to the reversible hydrogen electrode (RHE).…”

Layered double hydroxide-based nanomaterials for biomedical applications

“…Ultrafine LDHs with controllable size and shape were obtained by adjusting reaction temperature and pressure. 76 For example, CoFe-LDH nanoparticles of 200 nm were prepared by mixing two solutions containing Co/Fe nitrates and NaOH/Na 2 CO 3 respectively at a constant pH value of 8.0 and then transferring the mixture to a stainless-steel Teflon-lined autoclave for hydrothermal treatment at 80 1C for 24 h. 77 (c) Separate nucleation and aging steps. Similar to the hydrothermal synthesis method, this method involves hydrothermal treatment but different seed formation process.…”

Vacancy defect-promoted nanomaterials for efficient phototherapy and phototherapy-based multimodal Synergistic Therapy

“…It is worth noting that various nanomaterials have made significant contributions to phototherapy through both improving targeted therapeutic efficiency and reducing side effects ( Cheng et al, 2014 ; Liu Y. et al, 2019 ; Liu et al, 2021 ). Nanomaterials for phototherapy are usually composed of inorganic nanoparticles with strong NIR absorption and rapid NIR activation, such as noble metal, chalcogenide, transition metal oxide, polyoxometalate, transition metal carbide, and carbon-based nanoparticles ( Wang X. et al, 2019 ; Liu G. et al, 2019 ; Gu et al, 2019 ; Wang L. et al, 2020 ; Wang L. et al, 2021 ; Tian et al, 2021 ). The most key factor affecting the performance of phototherapeutic nanomaterials is their microstructure (i.e., electronic and geometric structures) which in principle determines their physicochemical properties and the resulting phototherapeutic efficacy ( Coughlan et al, 2017 ; Huang et al, 2017 ; Nosaka and Nosaka, 2017 ; Chen et al, 2021 ; Liu et al, 2021 ).…”

“…4) In addition, it should also show low toxicity but high biocompatibility to realize minimized side effects. Recently, thus, a great deal of efforts have been made to develop novel phototherapeutic nanomaterials with well-defined particle sizes, morphology, and compositions, such as various noble metal, semiconductor, and carbon-based nanomaterials ( Gao et al, 2018 ; Gu et al, 2019 ; Melo-Diogo et al, 2019 ; Wang L. et al, 2020 ; Zhou et al, 2020 ; Chang et al, 2021 ; Tian et al, 2021 ; Wang L. et al, 2021 ; Zhou C. et al, 2021 ). So far, however, the rational design and controllable synthesis of phototherapeutic nanomaterials in order to satisfy the above four properties simultaneously remains a vitally important and fundamental scientific problem.…”