【Angew.Chem.】武汉大学邹有全、华中师范大学肖文精|808 nm近红外驱动双通路光催化：实现54.95%光热转换与80%抑瘤率的协同肿瘤治疗#

文章标题：Near-Infrared Light Photocatalysis Enables Synergistic Cancer Therapy

通讯作者：Wen-Jing Xiao, You-Quan Zou

文章链接：https://doi.org/10.1002/anie.4230000

文章概要#

针对传统光催化剂依赖紫外或可见光导致的组织穿透深度受限及生物毒性高的问题，本研究设计并合成了基于铂(II)卟啉与七甲川氰乙炔色素共轭的近红外光催化剂。在808 nm近红外光照射下，该催化剂通过能量转移与单电子转移双重途径，同步产生多种活性氧并催化代谢辅酶NADH氧化，实现对肿瘤细胞能量代谢与氧化还原平衡的双重打击。封装生成的纳米颗粒兼具荧光/光声双模态成像与54.95%的高光热转换效率，不仅在体内取得80%的肿瘤抑制率，更成功激活全身抗肿瘤免疫反应以遏制远端转移，为近红外光催化协同肿瘤诊疗开辟了新途径。

引言#

光催化技术利用光能驱动化学反应，在能源与化学合成领域应用广泛。然而，将其拓展至活体生物系统面临着严峻的组织穿透与生物安全性瓶颈。传统的光催化体系大多依赖高能量的紫外或可见光激发，不仅对正常生物组织存在固有光毒性，且在组织中的穿透深度十分有限，严重阻碍了其在深部肿瘤治疗中的应用。近红外光具有穿透力强、光毒性低等优势，是生物医学应用的理想光源，但近红外光子能量较低，传统光催化剂难以直接响应。此前利用上转换材料等间接转换策略普遍面临能量转换效率低及生物相容性欠佳等挑战。因此，开发能够直接由近红外光驱动、兼具优异生物相容性与高效催化活性的新型光催化系统，成为光化学与生物医学交叉领域的重大科学课题。

Fig.1 Schematic illustration of NIR-activated PtTPP-TPA-IR808 NPs for photocatalysis and the targeted cancer therapy. DAMPs: damage-associated molecular patterns, DCs: dendritic cells, FL imaging: fluorescence imaging, ICD: immunogenic cell death, NADH: 1,4-dihydronicotinamide adenine dinucleotide, PA imaging: photoacoustic imaging, PDT: photodynamic therapy, PTT: photothermal therapy, ROS: reactive oxygen species.#

主要实验及结论#

研究团队将具有强系间跨越能力的Pt(II)卟啉与具有近红外吸收特性的七甲川氰乙炔色素通过共价键连接，成功合成了近红外光催化剂PtTPP-TPA-IR808（如图1和图2所示）。共价整合赋予了分子显著的天线效应，将其吸收峰扩展至近红外的786 nm区域。密度泛函理论计算与前沿轨道分析表明，分子的最高占据轨道（HOMO）分布于氰乙炔骨架，最低未占据轨道（LUMO）集中于铂卟啉单元，证实了分子内电荷转移特性（如图3所示）。在仿生组织模型中，该催化剂展现出深达8 mm的组织穿透能力。飞秒与纳秒瞬态吸收光谱分析揭示，铂重原子的引入显著促进了系间跨越过程（ $\tau_{\text{ISC}} \approx 53.8\text{ ps}$ ），产生了寿命长达1.6 μs的三重态，极大提升了光化学反应效率（如图4所示）。

Fig.2 Synthesis and characterization of NIR photocatalyst. (A) Synthetic route of PtTPP-TPA-IR808. (B) Normalized UV–Vis-NIR absorption spectra and FL spectra of TPA-IR808 in DMSO. (C) Normalized UV–Vis-NIR absorption spectra and FL spectra of PtTPP-TPA-IR808 in DMSO.#

Fig.3 Characterization of the NIR photocatalyst. (A–C) X-ray photoelectron spectroscopy (XPS) analysis of PtTPP-TPA-IR808: fully survey spectrum (A), Pt 4f region (B), and Br 3d region (C). (D, E) Zeta potentials of IR808, TPA-IR808, and PtTPP-TPA-IR808 in deionized water, determined by DLS. (F) The calculation of energy level orbit and geometric configuration at the ground state of PtTPP-TPA-IR808. (G) The fluorescence lifetime analysis of PtTPP-TPA-IR808. (H) Cyclic voltammetry (CV) of IR808, TPA-IR808, and PtTPP-TPA-IR808 (0.2 mM in DMF). Pt as counter electrode, Ag/AgCl, _n_Bu4NBF4 (0.1 M), scan rate 100 mV/s. (I) Decomposition rates of ABDA (50 µM) monitored at 378 nm in the presence of IR808, TPA-IR808, and PtTPP-TPA-IR808 under 808 nm laser irradiation (0.8 W cm−2). (J) Time-dependent changes in the FL intensity of DHE (40 µM) in the presence of IR808, TPA-IR808, and PtTPP-TPA-IR808 under 808 nm laser irradiation (0.8 W cm−2). (K) Time-dependent changes in the FL intensities of HPF (20 µM) in the presence of IR808, TPA-IR808, and PtTPP-TPA-IR808 under 808 nm laser irradiation (0.8 W cm−2).#

机理实验表明，PtTPP-TPA-IR808在808 nm光照下可同时通过能量转移生成单线态氧，并通过单电子转移接收代谢辅酶NADH的电子将其氧化为 $\text{NAD}^+$ ，同时将电子转移给氧气生成超氧阴离子与羟基自由基（如图3和图5所示）。核磁共振与光谱监测明确记录了NADH的转化过程，证实了该催化循环在热力学上的可行性（如图5所示）。此外，该化合物还具有优异的光热性能，其光热转换效率达54.95%，并具备良好的光声响应（如图3与图5所示）。

Femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) spectroscopy of the NIR photocatalyst. (A–C) The fs-TA pseudo-color maps of IR808 (A) and TPA-IR808 (B), and the ns-TA pseudo-color maps PtTPP-TPA-IR808 (C). (D–F) Corresponding time-resolved fs-TA spectra of IR808 (D), TPA-IR808 (E), and ns-TA spectra of PtTPP-TPA-IR808 (F) at selected pump-probe delay times. Different color lines represent spectra Fig.4 recorded at different delay times (solvent: DMSO). (G–I) Kinetics of the excited-state absorption (ESA) signal monitored for IR808 (G), TPA-IR808 (H), and PtTPP-TPA-IR808(I). Solid lines represent multi-exponential fits to the experimental data.#

Fig.5 Photocatalytic performance of PtTPP-TPA-IR808 toward NADH oxidation. (A) Schematic illustration for the photocatalytic oxidation of NADH to NAD+. (B) Plots of ln(A/_A_0) of NADH at 339 nm with different treatments and time intervals upon 808 nm laser irradiation (0.8 W cm−2). (C) Time-resolved UV-vis spectra during the oxidation of NADH (180 µM) catalyzed by PtTPP-TPA-IR808 (10 µM) under 808 nm laser irradiation (0.8 W cm−2). (D) The 1H NMR spectral changes [400 MHz, CD3OD/D2O (4: 1, v/v)] of NADH (3.5 mM) in the presence of PtTPP-TPA-IR808 (0.25 mM) upon 808 nm irradiation (0.8 W cm−2). (E) Proposed catalytic cycle for PtTPP-TPA-IR808-mediated ROS generation and NADH oxidation, involving single-electron-transfer (reductive quenching) and energy transfer pathways.#

研究人员采用磷脂聚乙二醇将其封装为平均水力学直径为79.38 nm的纳米颗粒（PtTPP-TPA-IR808 NPs）（如图6所示）。细胞实验显示，纳米颗粒在避光条件下安全性良好，而在808 nm光照下可使肿瘤细胞内NADH水平大幅降低85%。辅酶的耗耗导致线粒体膜电位崩溃，引发细胞周期停滞于G0/G1期与高达60%的细胞凋亡率，同时使肿瘤细胞的侵袭和迁移能力分别降低80%与70%（如图6所示）。此外，光催化反应成功触发了免疫原性细胞死亡，促进钙网织蛋白暴露与HMGB1释放，进而诱导树突状细胞成熟并分泌促炎因子IL-6和TNF- $\alpha$ （如图7所示）。转录组测序表明，该疗法显著调控了与细胞凋亡、NOD样受体、TNF及mTOR相关的通路（如图8所示）。

Fig.6 NIR photocatalytic activity in living cells. (A) Cell viability of 4T1 cells with different treatment following 808 nm laser (0.8 W cm−2) irradiation for 5 min, assessed by the CCK8 assay. (B) Live/dead staining of treated 4T1 cells using Calcein-AM (live, green) and propidium iodide (PI, dead, red), visualized by automated slide-scanning microscopy. Imaging channels: green (475 nm laser, 520–550 nm emitting filter); red (555 nm laser, 585–620 nm emitting filter). (C) Intracellular ROS generation and speciation in 4T1 cells treated with PtTPP-TPA-IR808 (5 µM) or PtTPP-TPA-IR808 NPs (10 µg/mL) and irradiated under 808 nm laser (0.8 W cm−2) for 5 min, detected by automated slide-scanning microscopy using DCFH-DA, DHE (O2•−) and HPF (•OH). Bottom panel: corresponding 3D fluorescence intensity surface plots generated with ImageJ. Imaging channels: green (475 nm laser, 520–550 nm emitting filter); red (555 nm laser, 585–620 nm emitting filter). (D) Cell invasion assay of 4T1 cells treated with PtTPP-TPA-IR808 NPs and irradiated with 808 nm laser (0.8 W cm−2) for 5 min. (E) The effect of PtTPP-TPA-IR808 NPs on the migration ability of 4T1 cells was detected by a wound healing assay. (F) Analysis of cell apoptosis by Annexin V-FITC/PI double staining and flow cytometry in 4T1 cells after different treatments. (G) Cell cycle distribution analyzed by flow cytometry in 4T1 cells after different treatments. (H) Schematic diagram of the electron transfer and metabolism-regulating the NADH/NAD+ balance. (I) Intracellular NADH levels in 4T1 cells after treatment with PtTPP-TPA-IR808 NPs at varying concentration under irradiation (808 nm, 0.8 W cm−2, 5 min). (J) Formazan formation in 4T1 cells (808 nm, 0.8 W cm−2, 5 min). Data are shown as the mean ± standard deviation with three replications. p < 0.05, p < 0.01, p < 0.001, ****p < 0.0001.#

Fig.7 Amplification of antitumor immunity mediated by PtTPP‑TPA‑IR808 NPs. (A) Schematic diagram of immunogenic cell death (ICD) induction in 4T1 cells. (B) Immunofluorescence staining images showing the exposure of CRT (green) and release of HMGB-1 (red) in 4T1 cells after indicated treatments. Nuclei are attained with DAPI (blue). Imaging channels: red (555 nm laser, 585–620 nm emitting filter); green (475 nm laser, 520–550 nm emitting filter); blue (390 nm laser, 450–480 nm emitting filter). (C) Quantification analysis of CRT exposure from 4T1 cells across different treatment groups. (D) Quantification analysis of HMGB1 release from 4T1 cells incubated with different treatments. (E) Representative confocal laser scanning microscopy (CLSM) images of mitochondrial membrane potential (MMP) changes in 4T1 cells detected by JC-1 staining after various treatments. Red fluorescence (J-aggregates) indicates high MMP; green fluorescence (JC-1 monomers) indicates low MMP. (F) Quantitative analysis of MMP in 4T1 cells after different treatments. (G) Schematic illustration of in vitro assessment of BMDCs maturation, created with Biorender.com. (H) The expression levels of IL-6 from BMDCs after different treatments. (I, J) Representative flow cytometry results of mature DCs (CD80+CD86+) after different treatments. Data are shown as the mean ± standard deviation with three replications. p < 0.05, p < 0.01, p < 0.001, ****p < 0.0001; ns, not significant.#

在4T1荷瘤小鼠体内实验中，荧光与光声双模态成像证实纳米颗粒在静脉注射24小时后于肿瘤部位高效富集（如图9所示）。在808 nm激光照射下，局部产生温和光热升温（达42.5°C），协同光催化生成的活性氧与NADH耗耗，实现了80%的原发肿瘤抑制率（如图9所示）。在双侧肿瘤转移模型中，仅对原发肿瘤实施光照，使脾脏内 $CD3^+CD8^+$ 细胞毒性T细胞比例提升1.2至1.9倍，通过强大的系统性抗肿瘤免疫效应成功抑制了远端未光照转移瘤的生长，且未引发明显的器官与血液毒性（如图10所示）。

Fig.9 Multimodal imaging of PtTPP-TPA-IR808 NPs in 4T1 tumor-bearing breast cancer model. (A) Schematic diagram of photoacoustic imaging. (B) Representative photoacoustic (PA) images of tumor tissues at 24 h after injected with PtTPP-TPA-IR808 NPs. (C) Photothermal images of tumor treated with PBS and PtTPP-TPA-IR808 NPs upon 808 nm laser irradiation (0.8 W cm−2). (D) The PA intensity in tumor site. (E) The temperature curves in tumor site. (F) Comparison of tumor growth inhibition curves and individual tumor growth curves of the 4T1 tumor-bearing mice with different treatments. p < 0.05, p < 0.01, p < 0.001, ****p < 0.0001.#

Fig.10 In vivo therapeutic efficiency of PtTPP-TPA-IR808 NPs on the bilateral tumor model. (A) Schematic illustration of the establishment of a bilateral tumor model, administration, and treatment schedules. (B) Representative images of excised tumor tissues and average weights of primary tumors and distant tumors in mice after 12 days treatment. Data are presented as mean values ± SD (n = 5). (C, D) Growth curves of primary tumors (C) and distant tumors (D) in mice after 12 days treatment. (E, F) Representative flow cytometry analysis and proportion of T cells in spleen (n = 5). (G) CD8 staining of tumor tissues obtained from the mice administrated with different formulations in a bilateral tumor model. p < 0.05, p < 0.01, p < 0.001, ****p < 0.0001, ns, not significant.#

总结及展望#

本研究开发了一种新型近红外驱动的光催化诊疗体系，克服了传统光催化剂组织穿透浅的瓶颈。该体系融合了近红外荧光与光声成像定位功能，在808 nm光驱动下实现双通路光催化活性氧生成与NADH消耗，并辅以高效光热效应，破坏了肿瘤细胞的氧化还原与代谢平衡。该过程不仅能有效消退局部肿瘤，还能通过诱导免疫原性细胞死亡激活全身性T细胞免疫，抑制远端转移。未来随着靶向修饰与联合免疫疗法的深入探索，该近红外光催化策略有望为深部肿瘤及转移瘤的临床精准诊疗提供有力支持。