Multifunctional Two-Dimensional CoreâShell MXene@Gold

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Multifunctional Two-Dimensional Core-Shell MXene@Gold Nanocomposites for Enhanced PhotoRadio Combined Therapy in the Second Biological Window Wantao Tang, Ziliang Dong, Rui Zhang, Xuan Yi, Kai Yang, Meilin Jin, Chao Yuan, Zhidong Xiao, Zhuang Liu, and Liang Cheng ACS Nano, Just Accepted Manuscript • DOI: 10.1021/acsnano.8b05982 • Publication Date (Web): 13 Dec 2018 Downloaded from http://pubs.acs.org on December 15, 2018

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Multifunctional Two-Dimensional Core-Shell MXene@Gold Nanocomposites for Enhanced Photo-Radio Combined Therapy in the Second Biological Window Wantao Tang1, Ziliang Dong2, Rui Zhang2, Xuan Yi3, Kai Yang3, Meilin Jin1, Chao Yuan1*, Zhidong Xiao1*, Zhuang Liu2, and Liang Cheng2* 1

College of Science, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China

2Institute

of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for CarbonBased Functional Materials & Devices, Soochow University Suzhou 215123, China

3School

of Radiation Medicine and Protection & School for Radiological and Interdisciplinary

Sciences (RAD-X), Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou, Jiangsu 215123, China E-mail: [email protected]; [email protected]; [email protected];

Abstract Multi-functional nanoplatforms with special advantages in the diagnosis and treatment of cancer have been widely explored in nanomedicine. Herein, we synthesize two-dimensional core-shell nanocomposites (Ti3C2@Au) via a seed-growth method starting from the titanium carbide (Ti3C2) nanosheets, a classical type of MXene nanostructure. After growing gold on the surface of Ti3C2 nanosheets, the stability and biocompatibility of the nanocomposites are greatly improved by the thiol modification. And importantly, the optical absorption in the near infrared region (NIR) is enhanced. Utilizing the ability of the high optical absorbance and strong X-ray attenuation, the

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synthesized Ti3C2@Au nanocomposites are used for photoacoustic (PA) and computed tomography (CT) dual-modal imaging. Importantly, the mild photothermal effect of the Ti3C2@Au nanocomposites could improve the tumor oxygenation, which significantly enhances the radiotherapy (RT). None obvious long-term toxicity of the nanocomposites is found at the injected dose. This work highlights the promise of special properties of MXene-based multifunctional nanostructures for cancer theranostics.

Keywords: titanium carbide nanocomposites, surface modification, dual-modal imaging; combined therapy, the synergistic effect

In recent years, cancer has gradually become one of the most concerned problems. Lots of people will suffer from various kinds of cancer every year.

1-3

Up to now, surgery, chemotherapy and

radiotherapy (RT) are still the primary methods for cancer treatment. However, these traditional therapies meet their own problems to a certain extent, such as limited treatment efficiency and the inevitable toxic effects.4 It is a great necessary to develop efficient methods to kill cancer.5,

6

Photothermal therapy (PTT) is a noninvasive method to ablate malignancies with hyperthermia, which has attracted extensive interest.7-10 A large number of functional nanomaterials with good absorbance property have been widely used for PTT, such as carbon-based nanomaterials,11, copper-based hybrid materials,13 gold nanostructures,14,

15

12

transitional metal dichalcogenides

(TMDCs),16-18 small organic molecules or polymers,19-22 and so on. However, most previous studies were mainly concentrated on PTT in the NIR-I window, which suffered the drawback of the limited penetration depth.7 In comparison, a deeper penetration could be achieved in the second NIR


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biological window (1000~1500 nm).22-25 Recently, NIR-II window induced PTT has shown better tumor ablation than that induced by the NIR-I window.26-29 Therefore, it is worthwhile to develop good NIR-II photothermal agents for cancer therapy. Transition metal carbides (MXenes), as a type of two-dimensional (2D) materials, have been widely used in nanomedicine due to their excellent physical and chemical properties.30-33 For example, (i) The MXenes possess excellent hydrophilic ability derived from their surface functional group; (ii) The primary constituent elements of the MXenes are either essential elements or inert to biological organisms, which guarantees the security of the material; (iii) The MXenes exhibit good optical absorption and photothermal conversion efficiency, providing opportunities for photoacoustic (PA) imaging and PTT. Recently, various groups including ours have synthesized Ti3C2 nanosheets by chemical exfoliation method for photothermal cancer therapy.34, 35 Due to the large surface area of the layer structure, MXenes were used for drug delivery system in cancer therapy.36, 37 Utilizing the high Z element of Ta and Hf, Ta4C3 and HfC nanosheets were also used for enhanced RT.38, 39 In order to improve the imaging properties, the MXenes with manganese oxide nanoparticles in-situ growth on them were also fabricated for multimodal imaging-guided cancer therapy.40 Moreover, some noble metals (Au, Ag, and Pd) were grown on the MXenes for surface-enhanced Raman scattering (SERS).41 However, to our best knowledge, the application of MXenes integrated with noble metals in cancer imaging and therapy was seldom reported. Herein, the multifunctional 2D core-shell structure of the Ti2C3@Au nanocomposites was synthesized by a seed-growth method for application in imaging-guided cancer therapy (Figure 1a). There are several advantages by Au growing on the surface Ti3C2 nanosheets. Firstly, the stability and the biocompatibility of the Ti2C3@Au nanocomposites was effectively improved by the thiol


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group. Secondly, the optical absorbance of the Ti2C3@Au nanocomposites was greatly enhanced both in the NIR-I and NIR-II biological windows. Thirdly, taking the advantages of the excellent optical performance and strong X-ray attenuation ability, the Ti3C2@Au nanocomposites were used for photoacoustic (PA) and computed tomography (CT) dual-modal imaging. By the mild photothermal effect, the nanocomposites were successfully applied in photothermally enhanced RT and achieved an excellent synergistic effect between them. Finally, the long-term toxicity evaluation experiment proved the proper biosafety of the synthesized nanomaterials. Our work highlighted the wide applications of MXene-based nanostructures for cancer imaging and therapy.

Results and Discussion Ti3C2 nanosheets were synthesized by a chemical exfoliation method according to the previous literature.34 Firstly, the MAX phase Ti3AlC2 nanosheets were etched by hydrofluoric acid (HF) to remove the Al layer, and then Ti3C2 nanosheets were obtained by adding TPAOH organic alkali to etch the Ti3AlC2 nanosheets. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that the Ti3C2 were mostly nanosheets with a size of ~200 nm (Figure 1b, Supporting Figure S1). Atomic force microscopy (AFM) showed that the thickness of the asprepared Ti3C2 nanosheets was ~ 2 nm (Supporting Figure S2), a little higher than the theoretical one, which was caused by the surface absorption of F- or -OH after exfoliation.35 X-ray diffraction (XRD) pattern of the Ti3C2 was consistent with the previously reported Ti3C2 Mxene nanomaterials34 (Figure 1g). Due to the low band gap of 0.1 eV, the Ti3C2 nanosheets showed good optical properties, which were favorable for their wide applications in nanomedicine.42,

43

UV-vis-NIR

absorbance spectrum showed a broad absorption band of the synthesized Ti3C2 nanosheets in the


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NIR-I region (700-1000 nm), which could be used for PTT (Supporting Figure S3). The Ti3C2 nanosheets attached by the hydroxyl group (-OH) on the surface were very stable in water for a long time. However, they would immediately aggregate in salt environments (such as PBS, 0.9% NaCl, Supporting Figure S4a). Until now, various methods have been used to improve their stability (e.g., soybean phospholipid, PVP),35 however, the aggregation problem was still not solved well. The weak coordination between the Ti3C2 and polymers would cause their dissociation and aggregation in the physiological solutions. It was a great urge to develop practical methods to enhance the stabilities of the MXene nanosheets in the physiological environments. Taking advantages of the surface modification with Au nanomaterials, we developed a seedgrowth method to prepare core-shell Ti3C2@Au nanocomposites and found that they could be modified easily and effectively (See Supporting Information).44 Specifically, Poly (allylamine hydrochloride, PAH), a positively charged polymer was introduced to modify Ti3C2 nanosheets and formed Ti3C2-PAH, making the zeta potential changed from -24 mV to 40 mV (Supporting Figure S5), which facilitated the adsorption of negatively charged Au seeds through the electrostatic interaction. Afterward, an in-situ seed-mediated Au growth was carried out by the reduction of HAuCl4 to form a dense of Au shell outside of the core of Ti3C2 nanosheets. TEM and SEM images showed the formation of a thick Au shell on the surface of the Ti3C2 nanosheets (Figure 1c, Supporting Figure S6), directly verifying the successful formation of the core-shell structure of the Ti3C2@Au nanocomposites. HAADF-STEM images and EDS also confirmed that the Au shell was grown on the Ti3C2 nanosheets (Figure 1d, Supporting Figure S7). Due to the Au growth on the surface, SH-PEG (Mw=5kDa) was used to modify the obtained Ti3C2@Au nanocomposites through the gold-thiol bond, which made it water-soluble and biocompatible (Supporting Figure S4b).


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Meanwhile, the thickness of the Au shell grown on the Ti3C2 nanosheets could be easily tuned by adding the different amount of the Au growth solution. With the augment of the Au growth solution, the thickness of the Au shell was increased (Figure 2a). When the ratio of Au : Ti was 2 : 1, the nanosheets were coated with Au nanoparticles with the thickness of ~30 nm (Figure 1e&f). The more increased ratio of Au to Ti, the higher optical absorption of Ti3C2@Au nanocomposites in both NIR-I and NIR-II windows. Especially, when the ratio of Au : Ti was increased to 2 : 1, the absorbance of the nanocomposites was enhanced about two times higher than that of the Ti3C2 nanosheets at 808 nm and three times higher at 1064 nm (Figure 2b). Such high absorbance would be beneficial for deeper penetration and photothermal cancer therapy. However, the absorbance would be decreased when the ratio increased to 4 : 1. Therefore, we chose the 2 : 1 ratio of Au : Ti for the following experiments, and the final ratio of Au : Ti measured by ICP-OES was 1.52 : 1. Meanwhile, we also synthesized Ti3C2-Au nanostructures via another method of the in-situ reduction due to the -OH group on the surface of the Ti3C2 nanosheets. Even adding more Au solution in the reaction system, only a bit of Au nanoparticles were grown on the surface and formed Ti3C2-Au nanostructures (Supporting Figure S8a). Unfortunately, the absorbance in the NIR windows was decreased (Supporting Figure S8b), which was not favorable for PTT. At last, we chose the Auseed growth method to synthesize Ti3C2@Au core-shell nanostructures instead of the in-situ approach. Due to the excellent absorbance properties of the synthesized core-shell Ti3C2@Au nanocomposites in the NIR-II region, we next investigated the photothermal property of the modified nanostructures. Different concentrations of Ti3C2@Au-PEG solution irradiated with 1064 nm laser were used to evaluate the photothermal behaviors, an apparent concentration-dependent temperature


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increasment was observed for the Ti3C2@Au core-shell nanostructures (Figure 2c, Supporting Figure S9). The temperature could be enhanced by 36.4 °C within 5-min irradiation, while the temperature change for water was only 4.8 oC under the same condition. All these results indicated the efficient photothermal conversion of the Ti3C2@Au-PEG. Compared with Ti3C2 nanosheets, the photothermal conversion efficiency of Ti3C2@Au was increased from 28.3% to 39.6% in 1064 nm or 30.7% to 34.3% in 808 nm (See Supporting Information, Figure S10), respectively, probably due to the Au coated on the surface of Ti3C2 nanosheets, which could enhance the absorbance of the Ti3C2 nanosheets (Figure 2d). Importantly, the synthesized Ti3C2@Au-PEG also showed much deeper penetration under 1064 nm laser irradiation than that under 808 nm laser irradiation (Supporting Figure S10). Next, we investigated the photothermal stability of the synthesized Ti3C2@Au nanosheets. No obvious change was observed during the five cycles of heating / cooling, implying the great potential of Ti3C2@Au-PEG nanocomposites as a durable photothermal agent (Figure 2e). The biocompatibility of the Ti3C2@Au-PEG nanosheets was firstly evaluated by the standard MTT assay.

We used PVP modified Ti3C2, Ti3C2-PVP nanosheets for comparison. None

cytotoxicity of Ti3C2@Au-PEG or Ti3C2-PVP nanomaterials was found to 4T1 cells at the high concentration, indicating the good biocompatibility of the synthesized Ti3C2@Au-PEG nanocomposites or Ti3C2-PVP nanosheets (Figure 3a). Due to the excellent photothermal properties, the Ti3C2@Au-PEG nanosheets were further used to kill cancer cells under the 1064 nm NIR-II laser irradiation (0.75 W /cm2, 5 min). It could be found that the 4T1 cells treated with Ti3C2@Au-PEG (50 g/mL) showed more effective tumor cells ablation than that of Ti3C2-PVP nanosheets, probably due to the higher photothermal conversion efficiency of Ti3C2@Au-PEG (Figure 3b). Calcein-AM


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(green) and PI (red) co-contained images were further used to confirm the effective photothermal ablation of 4T1 cancer cells incubated with Ti3C2@Au-PEG nanocomposites under the 1064 nm laser irradiation (Figure 3c). Such photothermal effect would be suitable for enhanced other types of cancer therapy by increasing the cellular uptake level of Ti3C2@Au-PEG nanocomposites (Supporting Figure S11). Utilizing the strong X-ray attenuation of Au element, we wondered whether the Ti3C2@AuPEG nanocomposites could be used to enhance radiotherapy. The clonogenic assay (Figure 3d, Supporting Figure S12) indicated an X-ray dose-dependent therapeutic efficiency. Furthermore, cells treated only with Ti3C2@Au-PEG, or exposed to X-ray indicated no obvious DNA destruction, while a salient DNA damage was achieved when the cells were treated with Au nanoparticles or Ti3C2@Au nanocomposites under X-ray irradiation (Figure 3e, Supporting Figure S13). According to these data, we could confirm that Ti3C2@Au-PEG was able to enhance RT efficiency by its strong X-ray attenuation capability. To further evaluate the in vivo behaviors, we investigated the blood circulation and the biodistribution of the Ti3C2@Au nanocomposites. Blood collected from Balb/c mice at various time points post intravenous (i.v.) injection of Ti3C2@Au-PEG was measured by ICP-OES to determine the concentration of Ti ion in the blood. Due to the excellent surface modification of SH-PEG, the as-prepared Ti3C2@Au-PEG showed a long blood circulation time and highly targeted to the tumor site, providing a potential nanoplatform for cancer treatment (Supporting Figure S14&S15). Owing to the strong NIR-absorbance of the Ti3C2@Au-PEG nanocomposites, photoacoustic imaging (PA) was further carried out by using the Ti3C2@Au-PEG nanosheets as the contrast agent. The Ti3C2@Au nanocomposites showed higher PA signal than that of Ti3C2 nanosheets at the same


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concentration (Figure 4a-c). PA signals were monitored at various time points post injection of Ti3C2@Au-PEG (Figure 4d). Strong PA signal was found in the tumor site at 24 h, which evidenced the high tumor uptake of Ti3C2@Au-PEG through the enhanced permeability and retention (EPR) effect (Figure 4e, Supporting Figure S15). Nanomaterials that comprise high atomic number element have been used for computed tomography (CT) imaging.45,

46

Based on this, we evaluated the capability of the Ti3C2@Au

nanocomposites as CT contrast. It could be found that the brightness of CT images and HU values of Ti3C2@Au were gradually enhanced with the increment of the concentration of Ti3C2@Au-PEG (Figure 4f&g), which indicated the important enhancement ability of Ti3C2@Au-PEG nanosheets for CT imaging. Then in vivo CT images acquired by 24 h post injection of Ti3C2@Au-PEG also revealed that CT signals at the tumor site increased significantly, suggesting high tumor retention of the Ti3C2@Au-PEG nanocomposites (Figure 4h&i). Taking advantages of the strong optical performance and X-ray attenuation ability, Ti3C2@Au nanostructures was successfully used for PA/CT dual-modal imaging. Motivated by the favorable in vivo behaviors of Ti3C2@Au-PEG and their strong optical absorption, in vivo PTT was conducted by Ti3C2@Au-PEG. It could be found that, after i. v. injection of Ti3C2@Au-PEG, a significant temperature increased under the 1064 nm laser irradiation (0.75 W/ cm2 or 1 W/cm2, 10 min) of the tumor site, while the tumor temperature of mice with PBS injection showed no obvious changes. In order to get the synergistic effect between PTT and RT, we used the laser with the lower power density (0.75 W/cm2) to treat the mice (Figure 5a&b). As we all know, mild PTT could promote the blood flow in the blood vessels and then overcome the tumor hypoxia.47 Detection of blood oxygen saturation and hypoxia immunohistochemical assay of the tumor was


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conducted to confirm it (See Supporting Information). Blood oxygen saturation was detected by PA imaging before and after the laser irradiation at different time intervals (5, 10, 30, and 60 min) (Figure 5c, Supporting Figure S16). After the laser irradiation, blood oxygen saturation nearly doubled than that of pre-injection and maintained for an hour. The same conclusion was drawn according to the immunofluorescence hypoxia staining assay (Figure 5d). It could be found that the mild photothermal heating of Ti3C2@Au-PEG under the NIR-II irradiation could effectively improve the tumor hypoxia microenvironment, which would enhance RT in the cancer therapy. In vivo PTT in the NIR-II window combined with radiotherapy was carried out with the Ti3C2@Au-PEG nanocomposites. Female Balb/c mice bearing 4T1 tumor were randomly divided into six groups: Control (1); PTT only (2); RT only (3); Ti3C2@Au-PEG + PTT (4); Ti3C2@Au-PEG + RT (5); and Ti3C2@Au-PEG + PTT + RT (6). The injection dose was 20 mg kg-1 in the treatment groups (4, 5, and 6). Mild PTT was firstly carried out at 24 h post injection of Ti3C2@Au-PEG, irradiated by 1064 nm laser (0.75 W/cm2) for 10 min, and then RT was followed by X-ray irradiation with the dose of 6 Gy. PTT alone with or without the injection of Ti3C2@Au under NIR-II laser irradiation showed no appreciable inhibition effect. Mice injected with Ti3C2@Au followed by X-ray irradiation showed a better tumor inhibition effect, indicating Ti3C2@Au could improve the efficiency of RT by the strong X-ray attenuation of Au. Notably, the most obvious tumor growth inhibition was found through the PTT-RT group with Ti3C2@Au injection, which showed the synergistic therapeutic effect (Figure 6a&b, Supporting Figure S17&18). After the various treatments, the tumor slices stained with hematoxylin and eosin (H&E) were further evaluated to verify the therapeutic effect (Figure 6c). As expected, the most severe destructions of tumor cells appeared in the PTT&RT combined group (Group 6), whereas other groups showed little or no


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damage to tumor cells. For further applications of the nanomaterials in vivo, their potential toxicity always required particular attention. After the various treatments, all mice showed no noticeable weight loss, demonstrating our nanomaterials were relatively safe for in vivo application (Supporting Figure S19). Moreover, H&E staining showed that no notable abnormality was observed in the major organs from the healthy mice and Group 6 with the combined treatment after a month post injection of Ti3C2@Au (Figure 6d). In general, our results suggested no noticeable potential toxicity effect caused by Ti3C2@Au-PEG nanocomposites.

Conclusion In summary, the 2D core/shell Ti3C2@Au nanocomposites were successfully synthesized via a simple seed growth method. Due to the Au growth on the surface of the Ti3C2 nanosheets, the stability of MXenes was greatly improved by the thiol chemistry, and the absorbance of the nanocomposites in the NIR-I and NIR-II windows was significantly enhanced. Utilizing the strong absorption in the NIR-II window and high X-ray attenuation abilities, the synthesized Ti3C2@Au nanocomposites were successfully used as good contrast agents for PA/ CT dual-modal imaging. Importantly, the mild photothermal effect of the nanocomposites in the NIR-II window also improved the tumor oxygenation, which could significantly enhance RT. Importantly, no apparent toxic side effect was found after injection of Ti3C2@Au-PEG nanocomposites for one month. In brief, our work developed a multifunctional 2D core-shell structure of the Au grown on Ti3C2 nanosheets for the enhanced absorbance in NIR I and II bio-windows, the improved stability, as well as the enhanced radiotherapy with improved the tumor oxygenation and no additional side effects.


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Therefore, our work highlighted the special superiorities of 2D multifunctional theranostic nanoplatforms. In the future, we can develop the multifunctional nanomaterials with nanoenzyme properties to tune the tumor microenvironment, further enhance the cancer therapy by photo or X-ray induced therapy.

Experiment Section Materials The Ti3AlC2 starting material was purchased from Beijing Forsman Scientific, HF (40%, purity >98%) were purchased from Sigma-Aldrich, Tetrapropylammonium hydroxide (TPAOH) were obtained from Fisher Scientific, and Sulfhydryl polyethylene glycol (SH-PEG, MW=5000) were purchased from Shanghai Yare Biotec. All chemicals were used as received without further treatment.

Synthesis of Ti3C2 nanosheets Firstly, the as-obtained Ti3AlC2 powers were pretreated by immersing them in diluted HF (20 %) at room temperature for 2 h and washed by water for three times. Then the treated Ti3AlC2 were dispersed in 25% aqueous TPAOH and stirred overnight. Finally, Ti3C2 nanosheets were purified by centrifugation and then washed three times.

Synthesis of Ti3C2@Au-PEG nanocomposites The seed-induced growth method was followed by the previous study (Supporting Information).44 Firstly, we prepared the gold seeds and growth solution, then the Ti3C2 solution was


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added dropwise into gold growth solutions and stirred for 2 h. A reducing agent formaldehyde (HCHO, 29%) was then introduced dropwise and stirred for another 1 h. Finally, SH-PEG (Mw=5000 Da) was added into the mixture to modify them and obtained Ti3C2@Au-PEG nanomaterials. For the control, bare Ti3C2 were modified with PVP (Mw = 40,000) following the same protocol.

Characterization Transmission electron microscope (TEM) imaging was taken on an FEI Tecnai F20 TEM at an acceleration voltage of 200 kV. Powder X-ray diffraction (XRD) spectra were gathered on a PANalytical X-ray diffractometer. The morphology and size of Ti3C2 nanosheets were characterized by AFM (Veeco Inc.). UV-vis-NIR absorption spectra were performed with a PerkinElmer UV-visNIR spectrophotometer. The dynamic light scattering (DLS) and zeta potential of nanoparticles were recorded using MALVERN ZEN3690. The absolute Au and Ti contents were measured by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry).

Cellular experiments 4T1 murine breast cancer cells were chosen to carry out the following cellular experiments, and cultured following the standard protocol. 4T1 cells were pre-seeded into 96-well plates and incubated with different concentrations of Ti3C2@Au-PEG or Ti3C2-PVP. After 24 h, the relative cell viabilities were measured by the standard thiazolyl tetrazolium (MTT) assay. For in vitro PTT, 4T1 cells were incubated with Ti3C2@Au-PEG or Ti3C2-PVP with the same concentration of Ti3C2 (50 g/mL) and then irradiated by a 1064-nm laser at different power


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densities (0.4, 0.6, and 0.75 W/cm2) for 5 min. After that, the relative cell viabilities were evaluated by the MTT assay. The live cells and dead cells were evaluated by calcein-AM and propidium iodide (PI) staining for 15 min and then analyzed by a confocal image. For the clonogenic assay followed by the previous study,47 Ti3C2@Au-PEG or PBS were used to pretreat the different amounts of cells for 24 h, then the cells were irradiated by X-ray with different doses. At least 50 cells in each group were defined as a clonogenic group. For γ-H2AX immunofluorescence staining following the previous study,48 4T1 were treated with PBS, Ti3C2@Au-PEG or Ti3C2-PVP at the same concentration of Ti3C2 (50 µg/mL) and exposed to X-ray (doses =6 Gy), then the cells were stained and analyzed by a confocal fluorescence microscope (Leica).

Tumor Model Balb/c mice were purchased from Suzhou Belda Biopharmaceutical Co. Ltd and treated following protocols approved by Soochow University Laboratory Animal Center. The subcutaneous 4T1 tumors were generated by subcutaneous injection of 4T1 cells (2 x 106) suspended in 50 L of PBS on the back of each female Balb/c mice. When the tumor volume reached ~100 mm3, the mice could be employed for in vivo experiments.

In vivo multimodal imaging For PA imaging, Ti3C2@Au-PEG and Ti3C2-PVP at the same concentration of Ti3C2 (0.5 mg/mL) were used for PA imaging (Sualsonic Vevo 2100 LAZER systems). For in vivo PA imaging, the 4T1 tumor-bearing mice were intravenously injected with Ti3C2@Au-PEG (20 mg/kg). The


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tumor region was imaged at different time points via a visual sonic system with an excitation wavelength at 910 nm. For CT imaging, Ti3C2@Au-PEG nanocomposites with varying concentrations dissolved in water were used for CT imaging. For in vivo CT imaging, mice bearing 4T1 tumors were intravenously injected with Ti3C2@Au-PEG before imaging (25 mg/kg). CT imaging of mice was conducted pre-injection and at 24 h post injection.

In vivo PTT/RT combined therapy Female Balb/c mice bearing 4T1 tumor were randomly divided into six groups: (1) Control; (2) PTT only; (3) RT only; (4) Ti3C2@Au-PEG + PTT; (5) Ti3C2@Au-PEG + RT; (6) Ti3C2@Au-PEG + PTT + RT. The injection dose was 20 mg kg-1 (group 4, 5, and 6). 24 h later, mice were irradiated by 1064 nm laser (0.75 W/cm2, 10 min) and / or X-ray irradiation (6 Gy) in different groups. The tumor growth and analysis were followed by the previous study.49 H&E stained major organs were obtained from mice with the treatment and the healthy group at 30 days.

ASSOCIATED CONTENT The authors declare no competing ﬁnancial interest.

Supporting Information The Supporting Information is available free of charge on the ACS Publications website. Materials characterization and supplementary figures (PDF).


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AUTHOR INFORMATION Corresponding Authors *E-mail: [email protected] (L. Cheng) *E-mail: [email protected] (C. Yuan) *E-mail: [email protected] (Z.D. Xiao)

Acknowledgments

This

article

was

partially

supported

by

the

National

Research

Programs

of

China

(2016YFA0201200), the National Natural Science Foundation of China (51525203, 51572180 and 21705054), the open funds of the State Key Laboratory of Agricultural Microbiology (AMLKF201809), a Jiangsu Natural Science Fund for Distinguished Young Scholars (BK20130005, BK20170063), Collaborative Innovation Center of Suzhou Nano Science and Technology, and a Project Funded by the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions.

References 1. Weinberg, S. E.; Chandel, N. S. Targeting Mitochondria Metabolism for Cancer Therapy. Nat. Chem. Biol. 2014, 11, 9. 2. Peer, D.; Karp, J. M.; Hong, S.; Farokhzad, O. C.; Margalit, R.; Langer, R., Nanocarriers as An Emerging Platform for Cancer Therapy. Nat. Nanotechnol. 2007, 2, 751. 3. Topalian, Suzanne L.; Drake, Charles G.; Pardoll, Drew M., Immune Checkpoint Blockade: A Common Denominator Approach to Cancer Therapy. Cancer Cell 2015, 27, 450-461. 4. Wilson, W. R.; Hay, M. P., Targeting Hypoxia in Cancer Therapy. Nat. Rev. Cancer 2011, 11, 393.


Page 17 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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5. Mo, R.; Jiang, T.; DiSanto, R.; Tai, W.; Gu, Z., ATP-triggered Anticancer Drug Delivery. Nat. Commun. 2014, 5, 3364. 6. Gotwals, P.; Cameron, S.; Cipolletta, D.; Cremasco, V.; Crystal, A.; Hewes, B.; Mueller, B.; Quaratino, S.; Sabatos-Peyton, C.; Petruzzelli, L.; Engelman, J. A.; Dranoff, G., Prospects for Combining Targeted and Conventional Cancer Therapy with Immunotherapy. Nat. Rev. Cancer 2017, 17, 286. 7. Cheng, L.; Wang, C.; Feng, L.; Yang, K.; Liu, Z., Functional Nanomaterials for Phototherapies of Cancer. Chem. Rev. 2014, 114, 10869-10939. 8. Liu, J.-n.; Bu, W.; Shi, J., Chemical Design and Synthesis of Functionalized Probes for Imaging and Treating Tumor Hypoxia. Chem.Rev. 2017, 117, 6160-6224. 9. Fan, W.; Yung, B.; Huang, P.; Chen, X., Nanotechnology for Multimodal Synergistic Cancer Therapy. Chem. Rev. 2017, 117, 13566-13638. 10. Wang, M.; Deng, K.; Lü, W.; Deng, X.; Li, K.; Shi, Y.; Ding, B.; Cheng, Z.; Xing, B.; Han, G.; Hou, Z.; Lin, J., Rational Design of Multifunctional Fe@γ-Fe2O3@H-TiO2 Nanocomposites with Enhanced Magnetic and Photoconversion Effects for Wide Applications: From Photocatalysis to Imaging-Guided Photothermal Cancer Therapy. Adv. Mater. 2018, 30, 1706747. 11. Yang, K.; Feng, L.; Shi, X.; Liu, Z., Nano-graphene in Biomedicine: Theranostic Applications. Chem. Soc. Rev. 2013, 42, 530-547. 12. Chen, G.; Roy, I.; Yang, C.; Prasad, P. N., Nanochemistry and Nanomedicine for Nanoparticle-based Diagnostics and Therapy. Chem. Rev. 2016, 116, 2826-2885. 13. Tian, Q.; Tang, M.; Sun, Y.; Zou, R.; Chen, Z.; Zhu, M.; Yang, S.; Wang, J.; Wang, J.; Hu, J., Hydrophilic Flower-Like CuS Superstructures as An Efficient 980 nm Laser-Driven Photothermal Agent for Ablation of Cancer Cells. Adv. Mater. 2011, 23, 3542-3547. 14. Huang, X.; El-Sayed, I. H.; Qian, W.; El-Sayed, M. A., Cancer Cell Imaging and Photothermal Therapy in the Near-Infrared Region by Using Gold Nanorods. J. Am. Chem. Soc. 2006, 128, 2115-2120. 15. Hu, M.; Chen, J.; Li, Z.-Y.; Au, L.; Hartland, G. V.; Li, X.; Marquez, M.; Xia, Y., Gold Nanostructures: Engineering Their Plasmonic Properties for Biomedical Applications. Chem. Soc. Rev. 2006, 35, 1084-1094. 16. Cheng, L.; Liu, J.; Gu, X.; Gong, H.; Shi, X.; Liu, T.; Wang, C.; Wang, X.; Liu, G.; Xing, H.; Bu, W.; Sun, B.; Liu, Z., PEGylated WS2 Nanosheets as A Multifunctional Theranostic Agent for in Vivo Dual-Modal CT/Photoacoustic Imaging Guided Photothermal Therapy. Adv. Mater. 2014, 26, 1886-1893. 17. Liu, J.; Zheng, X.; Yan, L.; Zhou, L.; Tian, G.; Yin, W.; Wang, L.; Liu, Y.; Hu, Z.; Gu, Z.; Chen, C.; Zhao, Y., Bismuth Sulfide Nanorods as A Precision Nanomedicine for in Vivo Multimodal Imaging-Guided Photothermal Therapy of Tumor. ACS Nano 2015, 9, 696-707. 18. Song, X.; Wang, X.; Yu, S.; Cao, J.; Li, S.; Li, J.; Liu, G.; Yang, H.; Chen, X., Co9Se8 Nanoplates as A New Theranostic Platform for Photoacoustic/Magnetic Resonance Dual-Modal-Imaging-Guided ChemoPhotothermal Combination Therapy. Adv. Mater. 2015, 27, 3285-3291. 19. Cheng, L.; He, W.; Gong, H.; Wang, C.; Chen, Q.; Cheng, Z.; Liu, Z., PEGylated Micelle Nanoparticles Encapsulating A Non-Fluorescent Near-Infrared Organic Dye as A Safe and Highly-Effective Photothermal Agent for in Vivo Cancer Therapy. Adv. Funct. Mater. 2013, 23, 5893-5902. 20. Carter, K. A.; Shao, S.; Hoopes, M. I.; Luo, D.; Ahsan, B.; Grigoryants, V. M.; Song, W.; Huang, H.; Zhang, G.; Pandey, R. K.; Geng, J.; Pfeifer, B. A.; Scholes, C. P.; Ortega, J.; Karttunen, M.; Lovell, J. F., Porphyrin–phospholipid Liposomes Permeabilized by Near-infrared Light. Nat. Commun. 2014, 5, 3546. 21. Lyu, Y.; Xie, C.; Chechetka, S. A.; Miyako, E.; Pu, K., Semiconducting Polymer Nanobioconjugates for Targeted Photothermal Activation of Neurons. J. Am. Chem. Soc. 2016, 138, 9049-9052. 22. Sun, H.; Lv, F.; Liu, L.; Gu, Q.; Wang, S., Conjugated Polymer Materials for Photothermal Therapy. Adv.Ther. 2018, 1, 1800057. 23. Jiang, Y.; Li, J.; Zhen, X.; Xie, C.; Pu, K., Dual-Peak Absorbing Semiconducting Copolymer Nanoparticles for First and Second Near-Infrared Window Photothermal Therapy: A Comparative Study. Adv. Mater. 2018, 30, 1705980. 24. Cui, J.; Jiang, R.; Guo, C.; Bai, X.; Xu, S.; Wang, L., Fluorine Grafted Cu7S4-Au Heterodimers for Multimodal Imaging Guided Photothermal Therapy with High Penetration Depth. J. Am. Chem. Soc. 2018, 140, 5890-5894. 25. Liu, P.; Wang, Y.; An, L.; Tian, Q.; Lin, J.; Yang, S., Ultrasmall WO3–x@γ-poly-l-glutamic Acid Nanoparticles as A Photoacoustic Imaging and Effective Photothermal-Enhanced Chemodynamic Therapy Agent for Cancer. ACS Appl. Mater. Interfaces 2018, 10, 38833-38844.


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26. Priya, V.; Cheng-Hong, L.; Raviraj, V.; Chi-Shiun, C.; Chu, H. K., Designing Multi-Branched Gold Nanoechinus for NIR Light Activated Dual Modal Photodynamic and Photothermal Therapy in the Second Biological Window. Adv. Mater. 2014, 26, 6689-6695. 27. Antaris, A. L.; Chen, H.; Cheng, K.; Sun, Y.; Hong, G.; Qu, C.; Diao, S.; Deng, Z.; Hu, X.; Zhang, B.; Zhang, X.; Yaghi, O. K.; Alamparambil, Z. R.; Hong, X.; Cheng, Z.; Dai, H., A Small-molecule Dye for NIRII imaging. Nat. Mater. 2015, 15, 235. 28. Yin, W.; Bao, T.; Zhang, X.; Gao, Q.; Yu, J.; Dong, X.; Yan, L.; Gu, Z.; Zhao, Y., Biodegradable MoOx Nanoparticles with Efficient Near-infrared Photothermal and Photodynamic Synergetic Cancer Therapy at the Second Biological Window. Nanoscale 2018, 10, 1517-1531. 29. Guo, B.; Sheng, Z.; Hu, D.; Liu, C.; Zheng, H.; Liu, B., Through Scalp and Skull NIR-II Photothermal Therapy of Deep Orthotopic Brain Tumors with Precise Photoacoustic Imaging Guidance. Adv. Mater. 2018, 30, 1802591. 30. Anasori, B.; Lukatskaya, M. R.; Gogotsi, Y., 2D metal Carbides and Nitrides (MXenes) for Energy Storage. Nat. Rev. Mater. 2017, 2, 16098. 31. Naguib, M.; Kurtoglu, M.; Presser, V.; Lu, J.; Niu, J.; Heon, M.; Hultman, L.; Gogotsi, Y.; Barsoum, M. W., Two-dimensional Nanocrystals Produced by Exfoliation of Ti3AlC2. Adv. Mater. 2011, 23, 4248-53. 32. Gogotsi, Y., Transition Metal Carbides Go 2D. Nat. Mater. 2015, 14, 1079. 33. Li, S.; Yang, W.; Liu, Y.; Song, X.; Liu, R.; Chen, G.; Lu, C.; Yang, H., Engineering of Tungsten Carbide Nanoparticles for Imaging-Guided Single 1064 nm Laser-activated Dual-type Photodynamic and Photothermal Therapy of Cancer. Nano Res. 2018, 11, 4859-4873. 34. Xuan, J.; Wang, Z.; Chen, Y.; Liang, D.; Cheng, L.; Yang, X.; Liu, Z.; Ma, R.; Sasaki, T.; Geng, F., Organic-Base-Driven Intercalation and Delamination for the Production of Functionalized Titanium Carbide Nanosheets with Superior Photothermal Therapeutic Performance. Angew. Chem. Inter. Ed. 2016, 55, 1456914574. 35. Lin, H.; Wang, X.; Yu, L.; Chen, Y.; Shi, J., Two-Dimensional Ultrathin MXene Ceramic Nanosheets for Photothermal Conversion. Nano Lett. 2017, 17, 384-391. 36. Xiaoxia, H.; Ju, H.; Han, L.; Zhigang, W.; Pan, L.; Yu, C., 2D Ultrathin MXene-Based Drug-Delivery Nanoplatform for Synergistic Photothermal Ablation and Chemotherapy of Cancer. Adv. Healthcare Mater. 2018, 7, 1701394. 37. Liu, G.; Zou, J.; Tang, Q.; Yang, X.; Zhang, Y.; Zhang, Q.; Huang, W.; Chen, P.; Shao, J.; Dong, X., Surface Modified Ti3C2 MXene Nanosheets for Tumor Targeting Photothermal/Photodynamic/Chemo Synergistic Therapy. ACS Appl. Mater. Interfaces 2017, 9, 40077-40086. 38. Dai, C.; Chen, Y.; Jing, X.; Xiang, L.; Yang, D.; Lin, H.; Liu, Z.; Han, X.; Wu, R., Two-Dimensional Tantalum Carbide (MXenes) Composite Nanosheets for Multiple Imaging-Guided Photothermal Tumor Ablation. ACS Nano 2017, 11, 12696-12712. 39. Lin, H.; Gao, S.; Dai, C.; Chen, Y.; Shi, J., A Two-Dimensional Biodegradable Niobium Carbide (MXene) for Photothermal Tumor Eradication in NIR-I and NIR-II Biowindows. J. Am. Chem. Soc. 2017, 139, 16235-16247. 40. Dai, C.; Lin, H.; Xu, G.; Liu, Z.; Wu, R.; Chen, Y., Biocompatible 2D Titanium Carbide (MXenes) Composite Nanosheets for pH-Responsive MRI-Guided Tumor Hyperthermia. Chem. Mater. 2017, 29, 86378652. 41. Satheeshkumar, E.; Makaryan, T.; Melikyan, A.; Minassian, H.; Gogotsi, Y.; Yoshimura, M., Onestep Solution Processing of Ag, Au and Pd@MXene Hybrids for SERS. Sci. Rep. 2016, 6, 32049. 42. Michael, N.; N., M. V.; W., B. M.; Yury, G., 25th Anniversary Article: MXenes: A New Family of Two-Dimensional Materials. Adv. Mater. 2014, 26, 992-1005. 43. Qi, X.; Huijie, Z.; Minshen, Z.; Zengxia, P.; Hongfei, L.; Zifeng, W.; Yang, H.; Yan, H.; Qihuang, D.; Jie, Z.; Shiyu, D.; Qing, H.; Chunyi, Z., Photoluminescent Ti3C2 MXene Quantum Dots for Multicolor Cellular Imaging. Adv. Mater. 2017, 29, 1604847. 44. Cheng, L.; Yang, K.; Li, Y.; Chen, J.; Wang, C.; Shao, M.; Lee, S.-T.; Liu, Z., Facile Preparation of Multifunctional Upconversion Nanoprobes for Multimodal Imaging and Dual-Targeted Photothermal Therapy. Angew. Chem. Inter. Ed. 2011, 50, 7385-7390. 45. Weissleder, R.; Nahrendorf, M.; Pittet, M. J., Imaging Macrophages with Nanoparticles. Nat. Mater. 2014, 13, 125. 46. Cheng, L.; Yuan, C.; Shen, S.; Yi, X.; Gong, H.; Yang, K.; Liu, Z., Bottom-Up Synthesis of MetalIon-Doped WS2 Nanoflakes for Cancer Theranostics. ACS Nano 2015, 9, 11090-11101.


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47. Cheng, L.; Shen, S.; Shi, S.; Yi, Y.; Wang, X.; Song, G.; Yang, K.; Liu, G.; Barnhart, T. E.; Cai, W.; Liu, Z., FeSe2-Decorated Bi2Se3 Nanosheets Fabricated via Cation Exchange for Chelator-Free 64Cu-Labeling and Multimodal Image-Guided Photothermal-Radiation Therapy. Adv. Funct. Mater. 2016, 26, 2185-2197. 48. Shen, S.; Jiang, D.; Cheng, L.; Chao, Y.; Nie, K.; Dong, Z.; Kutyreff, C. J.; Engle, J. W.; Huang, P.; Cai, W.; Liu, Z., Renal-Clearable Ultrasmall Coordination Polymer Nanodots for Chelator-Free 64Cu-Labeling and Imaging-Guided Enhanced Radiotherapy of Cancer. ACS Nano 2017, 11, 9103-9111. 49. Chen, Y.; Cheng, L.; Dong, Z.; Chao, Y.; Lei, H.; Zhao, H.; Wang, J.; Liu, Z., Degradable Vanadium Disulfide Nanostructures with Unique Optical and Magnetic Functions for Cancer Theranostics. Angew. Chem. Int. Ed. 2017, 129, 13171-13176.


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Figure 1. Characterization of Ti3C2@Au nanostructure. (a) Schematic illustration of the theranostic function of Ti3C2@Au, including Ti3C2@Au synthesis, PEGylation, and in vivo PA/CT dual-modal imaging-guided photothermal therapy combined with radiotherapy. (b&c) TEM images of assynthesized Ti3C2 nanosheets (b) and Ti3C2@Au nanocomposites (c). Inset: The corresponding magnified TEM image. (d) HAADF-STEM images of individual Ti3C2@Au nanocomposites. The


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element mappings showed the distribution of Ti (red) and Au (yellow). (e) AFM image of Ti3C2@Au nanocomposites. (f) The AFM-measured thickness of Ti3C2@Au nanocomposites. (g) XRD patterns of the Ti3C2 nanosheets and Ti3C2@Au nanocomposites.

Figure 2. Optical properties of Ti3C2@Au nanocomposites. (a) TEM images of Ti3C2@Au nanostructures prepared with various ratios of Au : Ti by adding different volumes of HAuCl4 growth solution. (b) UV-vis-NIR spectra of Ti3C2@Au-PEG prepared with multiple ratios of Au : Ti. (c) Photothermal heating curves of pure water and Ti3C2@Au nanocomposites with various concentrations (0.02, 0.04, 0.08, and 0.16 mgmL-1) under 1064 nm NIR-II laser irradiation at the power density of 0.75 W/cm2 for 5 min. (d) Photothermal effect of the same concentration of Ti3C2 and Ti3C2@Au under 1064 nm laser irradiation (0.75 W/cm2). (e) Temperature variations of Ti3C2@Au under 1064 nm laser irradiation for 5 cycles with the power density of 0.75 W/cm2 (0.04 mg/mL1, 10 min of irradiation for each period).


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Figure 3. In vitro cell experiments. (a) Relative viabilities of 4T1 cells after being incubated with various concentrations of Ti3C2 and Ti3C2@Au for 24 h. (b) Relative viabilities of 4T1 cells treated by Ti3C2 and Ti3C2@Au (50 g/mL of Ti3C2) with 1064 nm laser irradiation at different power densities for 5 min. (c) Confocal images of live (green) and dead (red) cells stained by Calcein-AM and PI after being treated with PBS or Ti3C2@Au with the laser irradiation or not. (d) Clonogenic survival assay of 4T1 cells with or without Au or Ti3C2@Au nanostructures under various radiation does (0, 2, 4, and 6 Gy). (e) Confocal fluorescence images of γ-H2AX stained 4T1 cells treated with PBS, RT (6 Gy), Ti3C2@Au, Ti3C2 + RT, and Ti3C2@Au + RT (6 Gy). Statistical analysis was performed using the student’s two-tailed test: *p < 0.05, **p < 0.01.


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Figure 4. In vivo dual-modal imaging with Ti3C2@Au nanocomposites. (a) PA imaging of Ti3C2 and Ti3C2@Au at the same concentration of Ti3C2 (0.5 mg/mL). (b) Relative PA signals of Ti3C2 and Ti3C2@Au from 680 nm to 970 nm. (c) Relative PA signal of Ti3C2 and Ti3C2@Au at 808 nm, 850 nm, 910 nm at the same concentration of Ti3C2 (0.5 mg/mL). (d) PA images of the tumor site at different time intervals (0, 2, 4, 6, 10, and 24 h). (e) Relative PA signal in tumors at various time intervals after i. v. injection of Ti3C2@Au nanocomposites. (f&g) CT images (f) and CT contrasts (g) of Ti3C2@Au at various concentrations. (h) CT images of 4T1 tumor-bearing mouse before (left) and after (right) injection with Ti3C2@Au. (i) In vivo CT contrasts before and after i. v. injection Ti3C2@Au nanocomposites.


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Figure 5. In vivo tumor hypoxia relief by the mild photothermal effect. (a&b) IR thermal images (a) and the corresponding tumor temperature changes (b) of 4T1 tumor-bear mice with i. v. injection of Ti3C2@Au under the 1064 nm laser irradiation with different power densities (0.75 W/cm2, and 1 W/cm2; dose = 20 mg/kg, irradiated at 24 h p. i.). (c) Images of blood oxygen saturation of tumors before and after irradiation at different time intervals. (d) Representative immunofluorescence images of tumor slices. The nuclei, blood vessels, and hypoxia areas were stained with DAPI (blue), anti-CD31 antibody (red), and anti-pimonidazole antibody (green), respectively.


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Figure 6. In vivo combined PTT-RT treatment. (a) Tumor volume growth curves of mice after various treatments (n = 5). NIR irradiation was conducted by 1064 nm laser at 0.75 W/cm2 for 10 min, while the dose for RT was 6 Gy. Control (1); PTT (2); RT (3); Ti3C2@Au + RT (4); Ti3C2@Au + PTT (5); and Ti3C2@Au + PTT + RT (6). (b) Photographs of tumors harvested from mice in 14 days after the treatments. (c) H&E stained tumor slides of mice with different treatments. Tumors were harvested 2 days after the treatments. (d) H&E stained slices of major organs of the healthy mice (Control) and the mice post i. v. injection of Ti3C2@Au with combined therapies at 30 days.


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Toc


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