Photocatalysis Enhancement for Programmable Killing of

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Biological and Medical Applications of Materials and Interfaces

Photocatalysis Enhancement for Programmable Killing of Hepatocellular Carcinoma through Self-Compensation Mechanisms based on Black Phosphorus Quantum Dot hybridized Nanocatalysts Shanyou Lan, Ziguo Lin, Da Zhang, Yongyi Zeng, and Xiaolong Liu ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b21820 • Publication Date (Web): 18 Feb 2019 Downloaded from http://pubs.acs.org on February 18, 2019

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ACS Applied Materials & Interfaces

Photocatalysis

Enhancement

for

Programmable

Killing of Hepatocellular Carcinoma through SelfCompensation

Mechanisms

based

on

Black

Phosphorus Quantum Dot hybridized Nanocatalysts Shanyou Lana,b,d, Ziguo Lina,b,d, Da Zhangb ,c ,d*, Yongyi Zenga,,b,c,d*, Xiaolong Liub,c,d a. Liver Disease Center, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, P. R. China b. The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou 350025, P. R. China c. Mengchao Med-X Center, Fuzhou University, Fuzhou 350116, P. R. China. d. The Liver Center of Fujian Province, Fujian Medical University, Fuzhou 350025, P. R. China

KEYWORDS: Black phosphorus dots, mesoporous silica, hypoxia, photocatalysis, aptamer, photodynamic therapy.

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ABSTRACT: Recently reported black phosphorus quantum dots (BPQDs) possess unique photocatalysis activities.

However,

the

environmental

instability

accompanied

by

hypoxic

tumor

microenvironment (TME) seriously hindered the bio-applications of BPQDs, especially in oxygen-dependent photodynamic therapy (PDT). Here, we construct a hepatocellular carcinoma (HCC) specific targeting aptamer “TLS11a” decorated BPQDs-hybridized nanocatalyst which can specifically target HCC tumor cells and self-compensate oxygen (O2) into hypoxic TME for enhancing PDT efficiency. The BPQDs-hybridized mesoporous silica framework (BMSF) with in-situ synthesized Pt nanoparticles (PtNPs) in the BMSF is simply prepared. After decorated by TLS11a aptamer / Mal-PEG-NHS, the resultant nanosystem (refer as Apt-BMSF@Pt) exhibits excellent environmental stability, active targeting ability to HCC cells and self-compensation ability of oxygen. Compared with the PEG-BMSF@Pt without H2O2 incubation, the PEGBMSF@Pt nanocatalyst exhibits 4.2-folds O2 and 1.6-folds 1O2 generation ability in a mimetic closed-system in the presence of both H2O2 and NIR laser. In a mouse model, the Apt-BMSF@Pt can effectively accumulate into tumor sites, and the core of BMSF subsequently can act as photosensitizer to generate ROS, while the PtNPs can serve as a catalyst to convert H2O2 to O2 for enhancing PDT through self-compensation mechanisms in hypoxic TME. By comparation of the tumor volume / weight, H&E and immunohistochemical analysis, the excellent antitumor effects with minimized side effects of our Apt-BMSF@Pt could be demonstrated in vivo. Taken together, the current study suggests that our Apt-BMSF@Pt could act as an active targeting nanocatalyst for programmable killing of cancer cells in hypoxic TME.


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INTRODUCTION In recent decades, ultrathin two-dimension (2D) black phosphorus based nanomaterials including quantum dots (BPQDs), nanosheets (BPNSs) have attracted dramatically attention in biomedicine applications, attributing to their excellent photocatalysis activities in photodynamic therapy (PDT), and broad photo absorption from ultraviolet (UV) to near-infrared (NIR) in photothermal therapy (PTT) [1-7]. However, owing to the lone-pair electrons, BPQDs / BPNSs are not stable in water-oxygen coexistence environment including the physiological conditions in bio-system

[8-9].

It can be degraded into phosphate groups, and subsequently hinder the PDT /

PTT efficacy in cancer phototherapy. To date, two main strategies have been employed to prevent BP from rapid ambient degradation. One approach is to use certain metal coordination, dropping, or covalent bonding to occupy the lone-pair electrons of phosphorus; the other approach is to form self-assembled or cooperated nanostructures such as micelles to isolate BPQDs from oxygen and water

[10-13].

Both strategies have been demonstrated to be effective to

prevent oxidation and suspend degradation of BPQDs. However, the second strategy is more favorable since it could be further functionalized for bio-medical applications due to the limited functional groups of BPQDs.

In current practice, incorporation functions to further smartly respond to TME (such as low pH, H2O2, GSH and hypoxia. et al) and specifically target to tumor cells would not only significantly reduce the toxicity to normal tissues but also could significantly improve the therapeutic efficiency.

[14-16].

Hypoxia and high hydrogen peroxide are the main characteristics of TME

involved in tumor therapeutic tolerance and inflammatory response, which can remarkably lower down the PDT efficacy [17, 18]. To overcome above issues, many efforts have been focused on the development of smart nanocarriers to supply molecular oxygen (O2) into tumor sites for


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enhancing PDT efficiency, such as delivering the hemoglobin, directly transporting O2 into tumors and generating O2 from H2O2 [19-23]. Comparing with those strategies, self-supply of O2 from environmental H2O2 is a simple “on-demand” way to replenish O2 by specific responding to TME stimuli. On the other hand, comparing with the traditional targeting ligands such as antibody or peptide, a single-stranded DNA aptamer with specific spatial structure, which acted as a powerful molecular targeting element, has been extensively designed for therapeutic targeting purpose due to its thermal stability, low weight and immunogenicity [24-27]. For example, Tan and co-authors have reported an aptamer hybridized DNA nanohydrogel for targeted and stimuli-responsive gene therapy

[28].

Recently, our group also developed an HCC-targeting

aptamer “TLS11a” modified nanosystem for programmable PDT / PTT / chemotherapy

[18, 29].

However, integrating TME stimuli with DNA aptamer into a nanocatalyst by a simple method for enhancing PDT efficiency and overcoming hypoxic TME still remains challenge. Herein, we constructed a new nanostructure that the TLS11a DNA aptamer decorated BPQDs / Pthybridized mesoporous silica framework worked as active targeting nanocatalyst for selfregulation of precise cancer phototherapy (Scheme 1). In our design, the BPQDs-hybridized mesoporous silica framework was synthesized by one-step method which was able to isolate BPQDs from oxidation. After in-situ synthesis of PtNPs, the BMSF@Pt could self-supply oxygen at H2O2 condition. By decorating TLS11a aptamer / PEG, the Apt-BMSF@Pt could active target to HCC both in vitro and in vivo, and the efficient inhibition of tumor growth was achieved by PtNPs mediated self-compensation mechanisms during the PDT process. Thus, we highlighted the potential of our Apt-BMSF@Pt as a smart therapeutic agent to respond to TME stimuli for self-regulation of precise cancer phototherapy.


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Scheme 1. Schematic illustration of the self-regulation of precise cancer phototherapy in vivo. In tumor, the TLS11a DNA aptamer grafted black phosphorus quantum dots (BPQDs) / Pthybridized mesoporous silica framework (Apt-BMSF@Pt) could specifically target to tumor sites and internalized into cancer cells. The PtNPs from Apt-BMSF@Pt could convert the excess H2O2 into O2 for overcoming the hypoxic conditions at tumor site, and subsequently self-supply O2 for enhanced PDT in hypoxic TME. RESULTS AND DISCUSSION Hypoxia and high hydrogen peroxide are the main characters of TME. The former feature could lower down the efficacy of PDT, while the latter feature might be utilized to overcome the hypoxia by catalyzing hydrogen peroxide to generate O2 for enhancing PDT in hypoxic TME [3033].

Herein, HCC specific targeting aptamer TLS11a grafted nanocatalyst based on BPQDs / Pt-

hybridized mesoporous silica framework was designed. As illustrated in Figure 1A and S1, the BPQDs with an average diameter of 4.7 ± 0.8 nm was first obtained according to the sonication exfoliation technique [1-3]. Afterwards, the negative charged BPQDs were mixed with the CTAC


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(as a template) via electrostatic interaction in an alkaline environment for 1hr, and then TEOS (as a silicon source) was drop-wisely added into above solutions for condensation around the CTAC template at 80oC. After cooling down, the CTAC was removed and then decorated by APTES [16, 34].

The morphology of BMSF-NH2 was evaluated by TEM. As shown in Figure 1B, the prepared

BMSF-NH2 showed a typical spherical shape with an average diameter of 51.5 ± 6.9 nm. As shown in Figure S2, the results clearly showed the existence of P from BPQDs, Si and O elements in the matrix of BMSF-NH2. To further confirm the existence of BPQDs in BMSF-NH2, thermogravimetric analysis (TGA) was investigated. As shown in Figure S3, during the 1st weight loss period, both of MSF (without BPQDs) and BMSF-NH2 showed minor mass lost above 130oC due to the loss of water and carbon deposit. For 2nd weight loss period, MSF exhibited the mass lost about 18.7% (140 to 800oC) and reach to the plateau (800 to 1000oC). However, the BMSF-NH2 showed high weight lost about 34.5% (140 to 800oC) due to the existence of BPQDs. Noteworthy, the mass of BMSF-NH2 was increased during the temperature up to 1000oC, because the P from BPQDs was converted to phosphate and subsequently enhanced the total mass. After adding the Pt(acac)2 solution, the PtNPs were then in situ generated through NaBH4 reductant according to previously reported methods into the BMSFNH2 [20, 35]. As shown in Figure 1C, the BMSF@Pt with a uniform particle size of 52.3 ± 5.7 nm was observed, and the enlarged picture clearly showed the existence of PtNPs on the BMSF. The pore size of BMSF-NH2 and BMSF@Pt were investigated by Barrett-Joyner-Haenda (BJH) model from the adsorption branch of isotherms. As shown in Figure S4, the average pore diameter of BMSF-NH2 and BMSF@Pt was calculated to be 4.65 nm and 3.63 nm with a relatively narrow pore size distribution, and the pore volume was also calculated to be 0.686 cm3g-1 and 0.587 cm3g-1, respectively. The shrunken pore diameter and pore volume might be


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due to the existence of PtNPs partly blocking the pore of BMSF. Furthermore, dynamic light scattering (DLS) results suggested that the hydrodynamic size of BMSF@Pt did not significantly change after in-situ synthesis of PtNPs (Figure 1D). To confirm the co-existence of BPQDs and PtNPs, the energy dispersive X-ray spectroscopy (EDS) analysis and STEM-HAADF were performed, respectively. As shown in Figure 1E, the EDS results showed the presence of P, Pt, O, Si, C, N elements in BMSF@Pt, and the results were further confirmed by STEM-HAADF image with the element signals corresponding to P, Pt, O, Si, respectively (Figure 1F). X-ray photoelectron spectroscopy (XPS) analysis further confirmed the existence of BPQDs and PtNPs in BMSF@Pt. As shown in Figure S5, the BMSF@Pt showed well-defined P 2p doublet, which can be convoluted into the two binding energy signals of P 2p3/2 and P 2p1/2 at 128.3 and 130.1eV [36]. In addition, the typical 4f Pt and 2p Si signal at 75 eV and 103 eV suggested the existence of Pt and Si element [37-38]. The zeta potential of BMSF showed negative charge with 27.57 mV, which was attributed to OH groups from TEOS (Figure 2A). After modification with APTES, the zeta potential of BMSF-NH2 was changed from -27.57 mV to 4.59 mV due to the existence of -NH2 group from APTES. In addition, the turnover of surface charge from positive to negative demonstrated the in situ generation of PtNPs. Furthermore, the biocompatibility of BMSF@Pt was improved by modification of Mal-PEG-NHS on the surface with the final negative charge of -9.2 mV. Fourier transform infrared (FTIR) was further investigated to confirm the existence of Mal-PEG-NHS. The results showed the increase of a peak at 1641 cm-1, attributing to the C=O–N stretching vibrations of PEG-BMSF@Pt (Figure 2B).


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Figure 1. (A) Schematic illustration of the synthesis of Apt-BMSF@Pt and the photocatalysis mechanism for enhancing PDT. (B) TEM image of BMSF-NH2 and (C) BMSF@Pt, the insert enlarged picture showed the PtNPs in the BMSF@Pt. (D) Hydrodynamic size of BMSF, BMSFNH2, BMSF@Pt, and PEG-BMSF@Pt; (E) EDS analysis of BMSF@Pt. (F) STEM-HAADF image, and the corresponding element mapping images of BMSF@Pt.


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Next, the environmental stability of BMSF-NH2 compared with BPQDs was investigated in water, PBS buffer (pH 7.4) and culture medium (containing 10% FBS) when exposed to air at room temperature, by Uv-vis-NIR absorption analysis. As shown in Figure 2C, the absorbance of BPQDs in water was significant decreased, and nearly dropped 78.6% after 24hrs incubation, comparing with the initial condition. In contrast, the absorbance of BMSF-NH2 in water was relative stable, and the intensity only dropped about 16.6% after 24hrs, and the results were similar as the BPQDs or BMSF-NH2 in PBS buffer solution (pH 7.4) and culture medium (containing 10% FBS) (Figure S6). These data indicated that the silica frameworks could effectively protect BPQDs from rapid ambient degradation in physiological conditions and air conditions. To investigate whether silica frameworks in BMSF-NH2 influenced the photocatalysis ability of BPQDs, the ROS generation of both BMSF-NH2 and BPQDs was then analyzed by DPBF probe (ROS detector). As shown in Figure 2F and 2G, the absorbance of BMSF-NH2 was gradually decreased under a 670 nm laser irradiation with the power intensity of 0.1W/cm2, and the data was similar as the BPQDs under the same laser power conditions. These results indicated that silica framework did not change the photocatalysis ability of BPQDs. To precisely compare the ROS generation ability of BMSF-NH2 and BPQDs, the ROS quantum yield of BMSF-NH2 and BPQDs were calculated according to the previous reported formula [39, 40]

(see the experimental section). By taking Methylene blue (MB, ΦΔ = 0.5) as a standard

photosensitizer

[39],

ΦΔBPQDs was estimated to be 0.142, while the ΦΔBMSF was estimated to be

0.166 (Figure S7 and Table S1). The slight enhancement of ΦΔBMSF might be due to the relatively large sectional area of BMSF-NH2 comparing with the BPQDs. Moreover, to further study the photocatalysis stability of BMSF-NH2 or BPQDs, these nanoparticle solutions containing DPBF probe were irradiated by a 670 nm laser for 5 min, respectively. As shown in Figure 2H and 2I,


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the ΔC/Co ratio in BPQDs was significant decreased, suggesting the reduction of photocatalysis ability due to the oxidation of BPQDs in water and air. However, the ΔC/Co ratio in BMSF-NH2 was only slightly changed because of the protecting effects of silica frameworks in the same conditions, which leaded to enhanced photocatalysis stability.

Figure 2. (A) The zeta potential and (B) FTIR spectra of BMSF, BMSF-NH2, BMSF@Pt, PEGBMSF@Pt. (C) Vis-NIR absorption spectra of BPQD and (D) BMSF dispersed in aqueous solution with different incubation time. (E) Normalized absorption spectra of BPQD and BMSFNH2 at 670 nm with different incubation time. (F) The absorbance of DPBF (100 μM) after photodecomposition by ROS generation in BPQD and (G) BMSF-NH2 upon the 670 nm laser


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irradiation (670 nm, 0.1 W/cm2); (H) and (I) Normalized absorption of DPBF at 415 nm after photodecomposition by ROS generation in BPQDs and (G) BMSF-NH2 at different times after the 670 nm laser irradiation for 5 min (670 nm, 0.1 W/cm2). Next, self-supply of O2 in tumors would be a favorable strategy for enhancing the therapeutic efficiency of oxygen-dependent therapies such as radiotherapy and PDT

[41].

To detect O2

production capacity of PEG-BMSF@Pt, the fluorescence intensity of O2 specific probes ([Ru(dpp)3]Cl2) in a mimetic closed-system in the presence of H2O2 was measured [42]. As shown in Figure 3A to 3C, the fluorescence of [Ru(dpp)3]Cl2 was dramatically decreased about 4.3folds in the presence of PEG-BMSF@Pt, suggesting the efficient production of O2 due to the PtNPs as a catalyst to convert H2O2 into O2, comparing with the PEG-BMSF@Pt alone without H2O2 and BMSF with or without H2O2 (Figure S9 and S10). Moreover, the enhanced ROS generation of PEG-BMSF@Pt was also investigated by ROS detector (DPBF) in a mimetic closed-system in the presence of both H2O2 and 670 nm laser. The results showed that the absorbance of DPBF was significantly decreased about 1.6-folds in PEG-BMSF@Pt group in the presence of H2O2 comparing with the PEG-BMSF@Pt without H2O2, which were much higher than that of BMSF with or without H2O2 (Figure 3D to 3F and S11). The 1O2 generation enhancement of PEG-BMSF@Pt with H2O2 upon a 670 nm laser irradiation was further investigated by the ESR measurement (Figure S12). By using 2, 2, 6, 6-tetramethylpiperidine (TEMP) as 1O2 trapping agent, we clearly saw the triplet ESR signal of 1O2 from BMSF-NH2 and PEG-BMSF@Pt with or without H2O2. However, the ESR signal of PEG-BMSF@Pt with H2O2 was much higher than that of BMSF-NH2 and PEG-BMSF@Pt alone, since the PtNPs could act as a catalyst to convert H2O2 into O2 for enhancing 1O2 generation. Furthermore, the biocompatibility of BMSF@Pt was investigated by hemolysis assay and no obvious hemolysis


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was observed in BMSF@Pt treated red blood cells, indicating the good biocompatibility of our BMSF@Pt (Figure S13). Above results suggested that the PEG-BMSF@Pt could act as a nanocatalyst to self-supply O2 for enhancing PDT efficiency. Active targeting to the tumors and selectively internalized into cancer cells were played vital roles in cancer therapy to minimize side effects

[24-27].

Thus, FAM labeled HCC-targeting

aptamer TLS11a and Cy5-NHS were used to decorate PEG-BMSF@Pt through Michael addition. The DLS results suggested that the size of Apt-BMSF@Pt was almost not changed (Figure 1D), while the zeta potential of Apt-BMSF@Pt has been reduced from -9.2 mV to -17.6 mV, attributing to the modification of negative charged TLS11a DNA aptamer (Figure 2A). To further prove the successful modification, the UV-vis-NIR absorbance was measured. As shown in Figure S14, comparing with PEG-BMSF@Pt alone, the Cy5 labeled PEG-BMSF@Pt or AptFAM-BMSF@Pt exhibited a new absorption peak at 650 nm, attributing to the Cy5 fluorescence. After excited by 633 nm, the fluorescence intensity of Cy5 labeled AptFAMBMSF@Pt was similar as Cy5 labeled PEG-BMSF@Pt, and was much higher than that of PEGBMSF without Cy5 (Figure S15). In addition, the AptFAM-BMSF@Pt exhibited significant higher fluorescence intensity at 525 nm than that of PEG-BMSF@Pt without aptamer. These results demonstrated that the Cy5 / TLS11a aptamer was successful co-decorated onto PEGBMSF@Pt (Figure S16).


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Figure 3. (A) and (B) Fluorescence spectra of Ru(dpp)3Cl2 in PEG-BMSF@Pt with or without H2O2 (100 μM) at different incubation times; (C) Normalized fluorescence intensity of Ru(dpp)3Cl2 at 625 nm based on (A) and (B); (D) and (E) The absorbance of DPBF (100 μM) after photodecomposition by ROS generation in PEG-BMSF@Pt with or without H2O2 (100 μM) after a 670 nm laser irradiation (0.1W/cm2); (F) Normalized absorbance of DPBF at 415 nm during photodecomposition by ROS generation upon a 670 nm laser irradiation at 0.1W/cm2 in the presence of PEG-BMSF@Pt with or without H2O2 (100 μM). For biomedical applications, low or non-toxicity was the key factor for materials. The dark toxicity of BMSF-NH2, PEG-BMSF@Pt, and Apt-BMSF@Pt were then investigated by cell viability assays (CCK8). HepG2 liver cancer cells and 7701 normal liver cells were both used to assess the toxicity of our prepared nanomaterials. As shown in Figure 4A and 4B, AptBMSF@Pt exhibited a very low toxicity on both 7701 cells and HepG2 cells with viable cells above 94.9% even when the concentration of BPQDs increased up to 120 μg/mL after 24hrs


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incubation, and the data were similar as BMSF-NH2 with viable cells of 91.8% and PEGBMSF@Pt with viable cells of 94.4%. Next, we investigated the HCC active targeting capacity of Cy5 labeled Apt-BMSF@Pt, while Cy5 labeled PEG-BMSF@Pt served as a negative control. As shown in Figure 4C, the Cy5 labeled Apt-BMSF@Pt with a strong red fluorescence (ex, 633 nm) was clearly observed in the intracellular of HepG2 cells by confocal laser scanning microscopy analysis (CLSM), and the intensity at 8hrs were much higher that of at 4hrs incubation, indicated that our Apt-BMSF@Pt could specific target to HepG2 cells and be efficiently uptaken through TLS11a aptamer mediated endocytosis. In contrast, the Cy5 labeled PEG-BMSF@Pt treated HepG2 cells showed a weak fluorescence (red), and the intensity at 8hrs was similar as that of Cy5 labeled PEG-BMSF@Pt at 4hrs, which might be due to the insufficient uptake of PEG-BMSF@Pt by HepG2 cells due to the lacking of target element and the negative charge of PEG-BMSF@Pt. To further confirm the targeting ability of our AptBMSF@Pt, we compared the cellular uptake between Apt-BMSF@Pt and PEG-BMSF@Pt (without aptamer) in HepG2 cells and normal liver cells (LO2 cells), respectively. As shown in Figure S17, the fluorescence intensity of Cy5 from the Apt-BMSF@Pt treated LO2 cells was as similar as the same cells treated with PEG-BMSF@Pt. In contrast, the fluorescence intensity of Cy5 from the Apt-BMSF@Pt treated HepG2 cells was much higher than that of PEG-BMSF@Pt treated cells, indicating the specific targeting ability of our Apt-BMSF@Pt. Since we demonstrated the PEG-BMSF@Pt could not only produce 1O2 in the presence of H2O2 and 670 nm laser irradiation through self-compensation mechanisms, but also could specific target and efficiently internalize into HepG2 cells, these features might benefit to antitumor effects of Apt-BMSF@Pt. To test this hypothesis, we first examined the intracellular ROS generation according to previously reported methods

[10, 15, 29].


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DCFH-DA was an ROS

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fluorescence indicator. As shown in Figure 5A and 5B, the HepG2 cells without any treatment showed a weak fluorescence (green) due to certain inherent oxidative stress inside cancer cells. Additionally, either laser irradiation (670 nm, 0.1W/cm2) or incubated with BMSF in dark did not induce any additional 1O2 generation in HepG2 cells. However, PEG-BMSF@Pt or AptBMSF@Pt treated cells in dark even showed slight decrease of fluorescence, which were duo to the converting of H2O2 to O2 by Pt. In contrast, the BMSF, PEG-BMSF@Pt or Apt-BMSF@Pt treated cells with 670 nm laser irradiation exhibited significant additional 1O2 production with the enhancement of fluorescence intensity.

Figure 4. Cell viability of (A) 7701 normal liver cells and (B) HepG2 cells treated with different dose of BMSF, PEG-BMSF@Pt and Apt-BMSF@Pt in dark condition (n = 5). (C) CLSM image of HepG2 cells treated with Cy5 labeled PEG-BMSF@Pt and Apt-BMSF@Pt for different incubation time, respectively.


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More obviously, the fluorescence intensity in PEG-BMSF@Pt treated cells was much higher than that of BMSF, attributing to PtNPs mediated oxygen-compensation mechanisms; Comparing with the fluorescence intensity of the cells treated with PEG-BMSF@Pt, much stronger fluorescence intensity was observed in Apt-BMSF@Pt treated cells due to both effective cellular up-taken by aptamer mediated endocytosis and oxygen-compensation mechanisms. Next, the antitumor effect of Apt-BMSF@Pt was analyzed by CCK8 assays. As shown in Figure 5C, Apt-BMSF@Pt, PEG-BMSF@Pt or BMSF-NH2 treated HepG2 cells showed a dose-dependent PDT effect when irradiated by a 670 nm laser (0.1W/cm2, 5 min), respectively. More obviously, the

Figure 5. (A) Schematic illustration of the synthesis of Apt-BMSF@Pt and their application in PDT treatment; (B) The DCFH-DA detection of intracellular ROS in HepG2 cells after indicated treatment; (C) Cell viability of HepG2 cells treated with the different doses of BMSF-NH2, PEGBMSF@Pt and Apt-BMSF@Pt upon a 670 nm laser irradiation for 5 min (0.1W/cm2) (n=5). The


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statistical analysis was performed with the two-tailed paired Student‘s t-test, *p

Photocatalysis Enhancement for Programmable Killing of

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