Highly Stable and Multifunctional Aza-BODIPY-Based

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Biological and Medical Applications of Materials and Interfaces

Highly Stable and Multifunctional Aza-BODIPY-Based Phototherapeutic Agent for Anticancer Treatment Yunjian Xu, Menglong Zhao, Liang Zou, Licai Wu, Mingjuan Xie, Tianshe Yang, Shujuan Liu, Wei Huang, and Qiang Zhao ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b18669 • Publication Date (Web): 03 Dec 2018 Downloaded from http://pubs.acs.org on December 6, 2018

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ACS Applied Materials & Interfaces

Highly

Stable

and

Multifunctional

Aza-

BODIPY-Based Phototherapeutic Agent for Anticancer Treatment Yunjian Xu,† Menglong Zhao,† Liang Zou,† Licai Wu,† Mingjuan Xie,† Tianshe Yang,† Shujuan Liu,*, † Wei Huang*, †, ‡ and Qiang Zhao*, † †Key

Laboratory for Organic Electronics and Information Displays & Jiangsu Key

Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wen yuan Road, Nanjing 210023, China. E-mail: [email protected], [email protected]. ‡Shaanxi

Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University

(NPU), Xi'an 710072, P.R. China. E-mail: [email protected]. KEYWORDS: aza-BODIPY, donor−acceptor−donor type, heavy atom effects, intramolecular photoinduced electron transfer, NIR phototherapeutic agents

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ABSTRACT

Phototherapy, as an important class of noninvasive tumor treatment methods, has attracted extensive research interest. Although a large amount of the near-infrared (NIR) phototherapeutic agents have been reported, the low efficiency, complicated structures, tedious synthetic procedures, and poor photostability limit their practical applications. To solve these problems, herein, a donor−acceptor−donor (D−A−D) type organic phototherapeutic agent (B-3) based on NIR aza-boron-dipyrromethene (aza-BODIPY) dye has been constructed, which shows the enhanced photothermal conversion efficiency and high singlet oxygen generation ability by simultaneously utilizing intramolecular photoinduced electron transfer (IPET) mechanism and heavy atom effects. After facile encapsulation of B-3 by amphiphilic DSPE−mPEG5000 and F108, the formed nanoparticles (B-3 NPs) exhibit the excellent photothermal stabilities and reactive oxygen and nitrogen species (RONS) resistance compared with indocyanine green (ICG) proved for theranostic application. Noteworthily, the B-3 NPs can remain outstanding photothermal conversion efficiency (η = 43.0%) as well as continuous singlet oxygen generation ability upon irradiation under a single-wavelength light. Importantly, B-3 NPs can

effectively

eliminate

the

tumors

with

no

recurrence

via

synergistic

photothermal/photodynamic therapy under mild condition. The exploration elaborates the photothermal conversion mechanism of small organic compounds and provides a guidance to develop excellent multifunctional NIR phototherapeutic agents for the promising clinical applications.


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1. INTRODUCTION The development of highly efficient tumor therapy methods has been always the research hotspot as traditional therapy methods usually result in inefficient performance caused by a series of unexpected side effect to patients during the treatments.1−3 Currently, all in one platforms concurrently and complementarily including accurate diagnosis and real-time phototherapeutic capabilities in situ have been drawing extensive research interest.4−7 Especially, accurate and timely phototherapies with mild methods could effectively eliminate tumors and exhibit negligible harm to normal cells.8−11 In addition, the imaging-guided combined photodynamic therapy (PDT) and photothermal therapy (PTT),12−17 as two kinds of noninvasive tumors phototherapies, could effectively inhibit tumor growth under the similar light triggering conditions. On the one hand, optical imaging, such as fluorescence imaging (FI) with excellent sensitivity in situ could accurately present signals of samples in tumor sites for guiding tumor therapy.18−21 On the other hand, under the guidance of imaging, the combined PTT and PDT contributed to solve the problems met when each one used alone.22−26 For example, the local heat produced by photothermal agents helped to boost blood flow and subsequently improve photodynamic performance, and this in turn could eliminate cancer cells with heat resistance.27 One of the common strategies to fulfill the synergistic PDT/PTT was to combine the organic dyes with intense near-infrared (NIR) absorption (650−900 nm) and inorganic photothermal agents.28,29 Nevertheless, the complicated synthetic routes to integrate multicomponent, intricate intrinsic treatment process with two lasers, and uncertain ratio of each component have limited their application.30 Therefore, it was highly desired to construct a single component but multifunctional NIR theranostic agent



with outstanding synergistic photodynamic/photothermal therapeutic performance under a single-wavelength light irradiation. Up to now, many inorganic materials have been used as phototherapeutic agents by taking advantage of their excellent stability and high photothermal conversion ability.31−33 In comparison with inorganic materials, organic phototherapeutic agents, especially small molecule ones, exhibit outstanding properties, such as well-defined chemical structure, adjustable absorption wavelength, and potential biodegradability.34,35 Nevertheless, the poor stability and inefficient photothermal conversion usually faced by organic molecules limited their biological applications as available NIR-absorbing organic agents.36 For example, some conventional cyanine dyes, especially indocyanine green (ICG) approved for practical use, still suffered from poor stability and inefficient photothermal conversion.35,36 These problems would lead to the misleading optical signal and inefficient phototherapeutic performance or even result in harmful side effect. Azaboron-dipyrromethene (aza-BODIPY) dyes, as an important kind of NIR dyes, display relatively excellent stability, considerable red-shifted absorption and high fluorescence quantum efficiency.37 They have been widely investigated in photovoltaics,38 imaging,39 and PDT.40 Furthermore, the parent 1,3,5,7-tetraphenylaza-BODIPY, as a representative electron-deficient core, could conjugate with the electron donor to develop a donoracceptor (D-A) type for enhanced red-shifted absorption.41,42 The studies indicated that aza-BODIPY with D-A structure were promising precursors of multifunctional theranostic agents for imaging guided phototherapy in vivo. Up to now, it was reported that only few works about aza-BODIPY acted as PTT/PDT synergetic agents for


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anticancer. Therefore, highly efficient multifunctional NIR nanotheranostic agent with excellent stability based on aza-BODIPY is still desired and remains to be developed. Herein, we have designed and synthesized highly stable and multifunctional azaBODIPY-based phototherapeutic agent (B-3) by taking advantage of intramolecular photoinduced electron transfer (IPET) mechanism and heavy atom effects (Scheme 1a). The exploration of fluorescence quantum yield, steady-state and time-resolved photoluminescence (TRPL) spectra have confirmed the synergistic performance of IPET mechanism and heavy atom effects for the enhanced photothermal conversion properties. Meanwhile, theoretical calculation confirms that IPET is also beneficial for the enhanced red-shifted absorption to a great extent. Noteworthily, after facile encapsulation of B-3 by amphiphilic DSPE−mPEG5000 and F108, the formed nanoparticles (B-3 NPs) exhibit significant advantages, such as good biocompatibility, high photothermal conversion efficiency (η = 43.0%), continuous singlet oxygen generation, excellent photothermal stability, high reactive oxygen and nitrogen species (RONS) resistance, and excellent enhanced permeability and retention (EPR) effects. With above advantages, the B-3 NPs have been utilized for effective inhibition of tumor growth by their excellent photothermal conversion and singlet oxygen generation performance in situ (Scheme 1b). The negligible dark toxicity of B-3 NPs is also confirmed by histological examination. This study will offer a guidance for developing excellent multifunctional NIR phototherapeutic agents for precise clinical applications.

2. RESULTS AND DISCUSSION 2.1. Design, Synthesis and Characterization of Aza-BODIPY Dye



The electron−donating and −accepting (D−A) system is a useful approach to construct low-bandgap organic dyes with red-shifted absorption for deep penetration in vivo.43 Besides, IPET mechanism is responsible for quenching of fluorescence, providing more chances for photothermal conversion.44 In addition, the introduction of amino group to aza-BODIPY can enhance NIR absorption.45 Herein, arylamino moieties and azaBODIPY core acted as the electron donor and the electron acceptor, respectively, because they were ideally aligned to promote IPET.45 Two bromine atoms were included at position 2 and 6 of aza-BODIPY skeleton for enhanced singlet oxygen generation via heavy atom effects.46 For comparison, dye B-1 and B-2 were also synthesized. Scheme S1 showed the synthetic procedure and chemical structures of B-1, B-2 and B-3. The intermediates and final compounds were fully confirmed by nuclear magnetic resonance (NMR) (see Supporting Information). We first investigated the photophysical and photochemical properties of the free molecules. B-1, B-2 and B-3 could dissolve well in common organic solvents (Figure S1), suggesting their good processability and post functionalization. The absorption spectra of B-1, B-2 and B-3 in N,N-dimethylformamide (DMF) were shown in Figure 1a. They exhibited intense absorption in 550−900 nm region with the maximal absorption peaks at 659 nm, 835 nm and 848 nm, respectively, which were attributed to the π-π* transitions originated from the azadipyrromethene skeleton.47 When compared to B-1, the maximal absorption of B-2 exhibited a 176 nm red-shift because of the extension of conjugation after attaching arylamino moieties to B-1, and that of B-3 exhibited a further 13 nm red-shift and broadened absorption owning to introducing bromine atoms to position 2 and 6 of aza-BODIPY skeleton, which were in accordance with the narrower


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energy gap of B-2 and B-3 than that of B-1 (Table S1). The strong NIR absorption of B-2 and B-3 matched well with biological window, suggesting their potential as phototherapeutic agents for NIR light-triggered biological application. Besides, compared to B-1 with strong emission, B-2 displayed relative weak emission while B-3 exhibited negligible emission under the same condition (Figure 1b), demonstrating that IPET mechanism and heavy atom effects could synergistically increase nonradiative conversion.

In

addition,

the

relative

radiative

quantum

yields

(QYs)

and

photoluminescence lifetimes of B-1, B-2 and B-3 were greatly reduced in turn, respectively. For example, their relative radiative QYs were 0.278, 0.003, and less than 0.001, respectively, and the photoluminescence lifetime were 4.32 ns, 1.86 ns, and 0.39 ns, respectively (Table S1). The above results further confirmed that IPET and heavy atom effects could effectively inhibit radiative decay process, which helps to offer more chances for photothermal conversion. Besides, IPET mechanism can effectively increase the red-shifted absorption of aza-BODIPY skeleton. The excellent photophysical properties of B-3 made it as promising photothermal agents for NIR light-triggered theranostic applications. In order to confirm the synergistic roles played by IPET mechanism and heavy atom effects, the photothermal conversion properties of B-1, B-2 and B-3 were first investigated. Based on our previous work,45 the temperature changes of samples with 10 μM in DMF were obtained via a thermal infrared imager under irradiation of 660 nm or 808 nm at 0.5 W cm−2 for 5 min, respectively. As shown in Figure 1c and S2, under the same condition, B-3 exhibited more evident temperature change than B-1 and B-2. For example, the temperature changes of B-1, B-2 and B-3 were about 5.9 oC, 17.4 oC and



18.7 oC under an 808 nm laser irradiation, and 9.2 oC, 12.7 oC and 13.8 oC under a 660 nm laser irradiation for 5 min, respectively. The results confirmed that IPET and heavy atom effects showed synergistic performance for enhancing photothermal conversion, and B-3 also showed higher photothermal conversion performance at 808 nm than B-1 at 660 nm. In addition, heavy atom effects could boost intersystem crossing (ISC) process for singlet oxygen generation. Then photodynamic performance of B-1, B-2 and B-3 were investigated with an 808 nm and 660 nm laser at 0.5 W cm−2, respectively. 1,3Diphenylisobenzofuran (DPBF) was used as singlet oxygen indicator. The singlet oxygen generation was confirmed by recording the characteristic absorption change of DPBF at 412 nm under irradiation. As illustrated in Figure 1d, S3 and S4, the characteristic absorption of DPBF only or its mixture with B-1 or B-2 showed negligible change during irradiation, suggesting no generation of singlet oxygen under a 660 nm or 808 nm laser irradiation. Whereas, under the irradiation of an 808 nm laser, the characteristic absorption of DPBF in its mixture with B-3 declined over 13% after irradiation for even 1 s, and 6 s later, the absorption decreased to 17% of original intensity, suggesting that B-3 at 808 nm also displayed more singlet oxygen generation than B-1 at 660 nm. Besides, the singlet oxygen quantum yields of B-1, B-2 and B-3 were also calculated as 0%, 0% and 39%, respectively, under a 660 nm laser irradiation. Furthermore, photosensitizers were usually irradiated by low laser power for their poor photostability. The characteristic absorption of B-2 and B-3 showed almost no change even with the large laser power, suggesting their excellent photostability during irradiation. The above results collectively confirmed that IPET and heavy atom effects could effectively boost photothermal conversion process. In addition, the introduction of bromine atoms could


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effectively improve the generation of singlet oxygen by heavy atom effects to a large extent. B-3 with the best photothermal conversion and singlet oxygen generation ability was chosen for the following tests. 2.2. Synthesis and Characterization of B-3 NPs To investigate the biological application of B-3 as biocompatible phototherapeutic agents, water-soluble B-3 nanoparticles (NPs) with 5.0 × 10−4 M were obtained by encapsulation referring to previous work (Figure S5).35 The schematic route of the encapsulation process was shown in Scheme 1b, and the detailed process was displayed in the Experimental Section. As shown in Figure 2a, Transmission electron microscopy (TEM) displayed a homogeneous spherical morphology with uniform size of 55.0 ± 3.0 nm in PBS. Dynamic light scattering (DLS) exhibited an average size of 80.2 nm in PBS, which could offer B-3 NPs the ability of tumor passive targeting via the EPR effects.48,49 Besides, the hydrodynamic diameter and TEM results of B-3 NPs in PBS showed almost no change during 24 h (Figure S6), suggesting the excellent chemical stability of B-3 NPs. In addition, the B-3 NPs could be homogeneously dispersed in PBS (pH = 7.4), suggesting their excellent water solubility and biocompatibility for biological application. The B-3 NPs displayed broad and red-shifted NIR absorption compared with B-3 in DMSO solution (Figure 2b), which was due to the aggregation within the micelle. The results were in accordance with previous report.48 Furthermore, the strong NIR absorption of B-3 NPs made them as promising photoacoustic agents for photoacoustic imaging (PAI). The PA signals vs concentrations of B-3 NPs displayed a relatively good linear relationship with R2 = 0.9849 (Figure S7), which provided the opportunity to monitor the distribution of B-3 NPs.



2.3. Photothermal Conversion Performance and Singlet Oxygen Generation Ability of B-3 NPs To confirm the multiple functions of B-3 NPs, their photothermal conversion performance and singlet oxygen generation ability was examined in PBS solution (pH = 7.4). The photothermal conversion performance of B-3 NPs was first explored in different concentrations by using an 808 nm laser at 0.5 W cm−2 in PBS. As shown in Figure 2c, with the rising of concentration, the maximal temperature changes of B-3 NPs increased rapidly. For instance, the temperature changes of B-3 NPs were 5.9, 13.0, 21.9, 29.7 and 36.6 °C at the concentrations of 5, 10, 20, 30 and 40 μM, respectively. By contrast, slight temperature increase was recorded for PBS only. Besides, the temperature change of B-3 NPs solution could reach up to 21.9 oC when the concentration of B-3 NPs was 20 μM, which could effectively suppress the growth of tumors.50 In addition, the excellent photothermal conversion efficiency of B-3 NPs was acquired as ~ 43.0% (Figure S8). It was super than those of common photothermal agents.13 Then the singlet oxygen generation performance of B-3 NPs was obtained by monitoring the characteristic absorption of 9,10-anthracenediyl-bis (methylene) dimalonic acid (ADMA) under irradiation by an 808 nm laser at 0.5 W cm−2. As shown in Figure 2d and S9, the absorption intensity of ADMA at 260 nm showed almost no changes, while that of the ADMA and B-3 NPs mixture decreased obviously under irradiation with time, indicating the continuous single oxygen generation. The singlet oxygen generation yield of B-3 NPs was also calculated as 34% (Figure S10). The above results confirmed that B-3 NPs could act as promising photosensitizer for PDT. 2.4. Photo- and Chemical Stability Studies of B-3 NPs


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Due to the fact that the decomposed phototherapeutic agents could lead to misleading signal, poor therapeutic efficacy or even fatal side effect in living systems,35 the tests of their

antiphotobleaching

performance,

photothermal

stability,

pH

or

RONS

(peroxynitrite (H2O2) or hydrogen peroxide (ONOO−)) resistance were carried out. And the antiphotobleaching properties of B-3 NPs, ICG and ICG NPs were first conducted under an 808 nm laser at 0.5 W cm−2 by monitoring their colors and maximal absorption, respectively. ICG NPs was obtained with the same method to B-3 NPs. As illustrated in Figure 3a and S11, the colors and the absorption spectra of B-3 NPs solution displayed almost no changes even under irradiation for 20 min. Conversely, the naked-eye distinguishable green color of ICG or ICG NPs solution disappeared and their characteristic absorption decreased to about 50% of original intensity even with irradiation for 5 min. After irradiation for 20 min, less than 20% of ICG or ICG NPs were left. The above results collectively indicated the excellent antiphotobleaching performance of B-3 NPs. Then photothermal stability of B-3 NPs in PBS (pH = 7.4) was investigated by comparing the temperature increase of ICG NPs and ICG under the same condition after alternative circle of heating and cooling process, respectively. Noteworthy is that even with eight circles, the photothermal conversion performance of B-3 NPs exhibited almost no changes with temperature change of about 28.5 °C, whereas the temperature changes of ICG or ICG NPs (ΔT ∼ 27.5 °C) all dramatically decreased to about 50% (ΔT ∼ 13.5 °C) of the initial value after two circles (Figure 3b and S12). Four circles later, the temperature changes of ICG or ICG NPs were less 30% of original value. These results confirmed the superior antiphotobleaching performance and photothermal stability of B-3 NPs than those of ICG. It was also



confirmed that ICG displayed similar properties to those of ICG NPs in antiphotobleaching performance and photothermal stability as well as photothermal conversion capability. In addition, the B-3 NPs with pH responsive functional groups might response to pH value, and their absorption in various pH solutions was obtained. As shown in Figure 3c and S13 a, their absorption showed almost no change in pH range of 5.0 ~ 7.4. The results might be resulted from the protection of DSPE−mPEG5000 and F108. Then the RONS (ONOO−, H2O2) resistance of B-3 NPs, ICG NPs and ICG was also explored, because highly reactive molecules such as ONOO− and H2O2, as very important signaling molecules, could regulate numerous physiological functions, as well as be expressed in many diseases.35 Therefore, RONS-resistant agents are considerably important for cancer diagnosis and treatment. Then, the stabilities of B-3 NPs were acquired in the presence or absence of RONS (H2O2, ONOO−) in PBS (pH = 7.4), respectively. As illustrated in Figure 3d, S13 b, S13 c and S13 d, the maximal absorption of B-3 NPs in its mixture with H2O2 displayed almost no change, while B-3 NPs in its mixture with ONOO− displayed slightly decreased maximal absorption to 95% of the original value. By contrast, the characteristic absorption decreased to 86% and 5% for ICG, 91% and 9% for ICG NPs of the original intensity in the presence of H2O2 and ONOO−, respectively. These results manifested that B-3 NPs exhibited super resistance to RONS (H2O2, ONOO−) than ICG, making B-3 NPs as promising phototherapeutic agents used in imaging and tumor therapy in vivo. 2.4 Cytotoxicity Assay and PTT/PDT Performance of B-3 NPs in Vitro


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To confirm photothermal conversion performance and singlet oxygen generation ability of B-3 NPs in vitro, their dark cytotoxicity was first investigated in Hela cells and 3T3 cells. Then the standard methyl thiazolyl tetrazolium (MTT) assay was utilized to evaluate the potential cytotoxicity of B-3 NPs. The cells were treated with B-3 NPs in different concentrations (0−200 μM) for 24 h, respectively. As illustrated in Figure 4a, the viability of Hela cells or 3T3 cells decreased slightly with increasing concentrations of B-3 NPs. For example, the viability of all cells was above 86% even with the concentration of B-3 NPs at 100 μM, and it was also above 80% even at their high concentration up to 200 μM, revealing the negligible dark cytotoxicity of B-3 NPs to Hela and 3T3 cells below 200 μM. The negligible dark cytotoxicity of B-3 NPs, attributed to the modification of polymer F108 and DSPE−mPEG5000, made them as potential phototherapeutic agents for clinical application. To confirm the phototherapeutic performance of B-3 NPs in vitro including singlet oxygen generation, Hela cells were treated with B-3 NPs or PBS for 4 h, and then irradiated under an 808 nm laser at 0.5 W cm−2 for 5 min, respectively. 2’,7’Dichlorofluoresceindiacetate (DCFH-DA) was chosen as the indicator of singlet oxygen. Under same irradiation condition, Hela cells with PBS showed dim green fluorescence, while the cells incubated with B-3 NPs exhibited intense green fluorescence (Figure 4b), suggesting the generation of intracellular ROS. The results confirmed the photodynamic performance in phototherapy induced by B-3 NPs under irradiation. In order to select suitable laser power for in vivo experiments, the Hela cells were treated with PBS (pH = 7.4), B-3 NPs, B-3 NPs plus VC, B-3 NPs plus hypoxia (oxygen concentration at 5%), and then irradiated in different laser power (0−0.9 W cm−2),



respectively. As illustrated in Figure 4c, with increasing laser irradiation, cells without B-3 NPs showed slightly decreased viabilities, while the rapidly decreased viabilities of cells incubated with B-3 NPs were observed. For example, the viabilities of cells incubated with B-3 NPs were even below 50% of original number even with the laser power at 0.5 W cm−2, while the viabilities of cells without B-3 NPs was still up to 90% of original. The viability of cells treated by B-3 NPs plus VC was higher than that of cells treated by B-3 NPs under irradiation, suggesting that the synergistic photothermal and photodynamic therapeutic performance was superior to photothermal effect only. In addition, the cells treated with B-3 NPs under hypoxia displayed higher viability than those under normal oxygen concentration, manifesting that photodynamic performance also played an important role even under hypoxia. At last, 0.5 W cm−2 was selected to conduct the following experiments. In order to further confirm the superior therapeutic performance of B-3 NPs, we carried out the flow cytometry experiments. Hela cells were treated with B-3 NPs or not without irradiation, B-3 NPs under oxygen concentration at 5%, B-3 NPs or B-3 NPs plus VC under an 808 nm laser irradiation at 0.5 W cm−2 for 5 min. Annexin V-FITC and propidium iodide (PI) were used for differentiating apoptotic cells and dead cells, respectively. As illustrated in Figure 5a and S14, the viability of Hela cells treated with only B-3 NPs, only laser irradiation or only PBS exhibited high cell viability of 92.1%, 95.2% and 96.0%, respectively, indicating negligible influence of laser or B-3 NPs to Hela cells. By contrast, Hela cells treated with B-3 NPs, B-3 NPs under hypoxia or B-3 NPs plus VC under irradiation showed obviously decreased viability. For example, they were 38.0%, 45.5%, 54.5%, respectively, further confirming the excellent photothermal


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conversion ability of B-3 NPs and the important role of photodynamic performance in phototherapy even under hypoxia. In order to further demonstrate the therapeutic effects of B-3 NPs under hypoxia, fluorescent live/dead cell imaging was further launched with the same condition. As illustrated in Figure 5b and S15, no or negligible green and red fluorescence was observed in Hela cells with PBS even after irradiation for 4 h, indicating almost no apoptotic cells. By contrast, Hela cells incubated with B-3 NPs showed intense green and red fluorescence, and the morphology of cells shrunk or even reshaped after irradiation for 4 h, manifesting the excellent therapeutic performance of B3 NPs under hypoxia, which is consistent with the above results. 2.5 Fluorescence Imaging of B-2 NPs and Photothermal Imaging of B-3 NPs in Vivo B-2 NPs with intense NIR emission showed similar physical properties to B-3 NPs with no fluorescence emission because of their similar structure (Figure S16). Hence the FI of B-2 NPs in vivo was utilized to confirm the therapeutic time point. FI of mice intravenously injected with B-2 NPs (200 μM, 150 μL) was investigated with time. As illustrated in Figure 6a, no FI signal was observed in tumor sites before injection of B-2 NPs. 2 hours after injection of B-2 NPs, weak fluorescence was observed in tumor sites. With time, the intensity of FI signal in tumor parts increased. And 4 hours later, it was up to the brightest. Meanwhile, strong fluorescence intensity was obtained in tumor parts, by contrast, weak or negligible fluorescence intensity was observed in other organs (Figure S17). The result indicated the rich accumulation of B-2 NPs in tumor parts, which was resulted from the excellent EPR effect of B-2 NPs. And 24 hours later, no FI signal in tumor parts was observed, suggesting that B-2 NPs in tumor parts has been metabolized. From the results observed in Figure 6a, the referential therapeutic time point was chosen



as 4 h after intravenous injection of B-3 NPs. In order to further confirm that B-3 NPs can accumulate in tumor sites indeed at the referential time point, infrared thermal imaging of mice was carried out under irradiation of an 808 nm laser at 0.5 W cm−2. As shown in Figure 6b and 6c, tumor sites with B-3 NPs injection displayed evident temperature increase in 1 min under irradiation, and it was up to ~ 53 °C (ΔΤ ∼ 18 °C) after irradiation for 5 min. The results could lead to irreversible tumor damage. While the temperature elevation of that with PBS injection exhibited no obvious change, confirming the excellent passive tumor targeting ability and photothermal conversion effects of B-3 NPs in vivo. And 4 h after intravenous injection of B-3 NPs was chosen as the referential therapeutic time point for the following experiments. To prove singlet oxygen generation in tumors during phototherapy, the mice injected with B-3 NPs or saline were chosen for next experiments. VC acted as ROS-scavenger and DCFH-DA was chosen as singlet oxygen indicator. 4.5 h later, the tumors were irradiated or not under irradiation of an 808 nm laser at 0.5 W cm−2 for 5 min. As illustrated in Figure 6d, the obvious green ﬂuorescence was captured in the tumor section of mice injected with B-3 NPs under irradiation. By contrast, the cells with B-3 NPs in the absence of irradiation or in the existence of VC induced negligible green ﬂuorescence. The result confirmed that B-3 NPs could generate sufficient singlet oxygen at tumor sites under irradiation, suggesting promising photodynamic performance against tumors. 2.6 In Vivo PTT/PDT Synergistic Therapy Inspired by the excellent synergistic photodynamic and photothermal performance of B-3 NPs in vitro, phototherapy of tumors was launched on the Hela tumor mouse model. The mice were treated with I) B-3 NPs (150 μL, 200 μM) + laser irradiation (808 nm, 0.5 W


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cm-2, 5 min), II) B-3 NPs + VC + laser irradiation, III) PBS + laser irradiation, IV) B-3 NPs only, V) PBS only, respectively. The first two groups acted as experimental groups, and the rest acted as control groups. The tumor volume and mice weight were recorded in all groups every two days before next therapy, because they were important parameters to evaluate therapeutic performance in vivo. As illustrated in Figure 7a, the tumors of mice in the control group showed an obvious growth with time. And the sizes of mice tumors in the control group were 8−10 times of the original size after 24 days. Compared to the mice in control groups with fast-growing tumor volumes, the tumors of mice in the experimental group showed black burn marks before the second therapy, and the tumors disappeared before the sixth therapy (Figure 7c). Besides, the tumors of mice treated with B-3 NPs were removed more quickly than those treated with B-3 NPs plus VC under the same laser irradiation, which was attributed to the fact that the less and less oxygen in tumor parts with the forming of scars can weaken the PDT effects during tumor therapy. The results suggested that photodynamic therapy also played a role for anticancer in vivo. And there was no new tumor observed 24 days after therapy. The above results suggested that B-3 NPs can effectively remove the tumors under irradiation. During the therapeutic period, the body weight of mice (~ 20 g) in control and experimental groups displayed similar growth trend (Figure 7b), suggesting the negligible side effects of B-3 NPs or laser to mice. All above results collectively confirmed that B-3 NPs could act as a promising phototherapeutic agent for practical application. In order to further evaluate the dark toxicity of B-3 NPs in vivo, the mice injected with B-3 NPs plus VC or not, or PBS under irradiation were sacrificed on day 24,



respectively.

As

is

well-known,

nanomaterials

tended

Page 18 of 39

to

accumulate

in

reticuloendothelial system (RES) organs, such as kidney and spleen. And the major organs were obtained for histological hematoxylin and eosin (H&E) staining. As illustrated in Figure 7d, the H&E staining showed similar and normal morphological characteristics with negligible tissue damage in major organs from all mice. The results suggested the negligible harm of B-3 NPs to RES organs, although they accumulated there. It demonstrated that B-3 NPs displayed negligible side effects in vivo during the PTT/PDT period.

3. CONCLUSION In

summary,

a

multifunctional

NIR

phototherapeutic

agent

based

on

donor−acceptor−donor (D−A−D) type organic small molecule (B-3) has been successfully developed and synthesized by utilizing IPET mechanism and heavy atom effects. The studies on photophysical and photochemical properties demonstrate that IPET mechanism and heavy atom effects can synergistically improve photothermal conversion performance of aza-BODIPY skeleton via increase of nonradiative process. Besides, IPET mechanism shows advantage on increasing the maximal absorption wavelength of aza-BODIPY skeleton. In addition, heavy atom effects can effectively boost the singlet oxygen generation ability of phototherapeutic agent via the introduction of bromine atoms at position 2 and 6 of aza-BODIPY skeleton. After facile encapsulation by DSPE−mPEG5000 and F108, water soluble B-3 NPs with uniform size exhibit excellent biocompatibility and concentration-dependent PA signal. Noteworthily, the B-3 NPs exhibit super resistances for photobleaching, heat and RONS. The B-3 NPs still show


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high photothermal conversion performance (η = 43.0%) and continuous singlet oxygen generation ability under irradiation (808 nm, 0.5 W cm−2). Imaging investigation in vivo suggests that B-3 NPs can enrich in tumor sites via EPR effects. The tumor phototherapy under mild condition in vivo demonstrates the highly efficient therapeutic performance by B-3 NPs and negligible side effect of laser irradiation or B-3 NPs. The H&E staining further confirm the negligible dark toxicity of B-3 NPs in vivo. This work elaborates the photothermal conversion mechanism of small organic compounds and provides a guidance to develop excellent multifunctional NIR phototherapeutic agents for the promising clinical applications.

4. EXPERIMENTAL SECTION 4.1. Experimental Information. The related materials, solvent, instruments, small animals and detailed experimental conditions could be acquired in the Supporting Information. 4.2. Synthesis of B-3 and B-3 Nanoparticles (B-3 NPs) Synthesis and characterization of B-1 and intermediate products could be acquired in the Supporting Information. Synthesis and Characterization of B-2. BF3·OEt2 (0.78 mL, 6.24 mmol) was slowly added into the mixture of dry CH2Cl2 (15 mL), 3 (0.27 g, 0.40 mmol) and diisopropylethylamine (2 mL), which then reacted at 25 oC for 4 h. The blue solid B-2 0.27 g (Yield: 95 %) was obtained by column chromatography. 1H NMR (400 MHz, CDCl3) δ (ppm): 8.10 – 8.04 (m, 8H), 6.91 (s, 2H), 6.78 (d, J = 8.8 Hz, 4H), 6.72 (d, J = 9.2 Hz, 4H), 3.45 (q, J = 6.8 Hz, 8H), 3.05 (s, 12H), 1.22 (t, J = 6.8 Hz, 12H). 13C NMR



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(100 MHz, CDCl3) δ (ppm): 155.64, 150.53, 149.03, 144.92, 140.94, 131.49, 130.38, 121.95, 119.09, 114.74, 112.01, 111.14, 44.47, 40.36, 29.71, 12.79.

19F

NMR (376.5

MHz, CDCl3): δ (ppm) = -131.31 (q, 2F). MALDI-TOF-MS m/z: 725.74. Synthesis and Characterization of B-3. N-bromosuccinimide (NBS) (0.10 g, 0.28 mmol) in CH2Cl2 (2 mL) was slowly added into the mixture of dry CH2Cl2 (10 mL) and B-2 (0.20 g, 0.28 mmol), which then reacted at 25 oC for 6 h. Column chromatography on silica gel with 50% ethyl acetate/hexane gave the blue solid B-3 0.07 g (Yield: 30 %). 1H NMR (400 MHz, CDCl3) δ (ppm): 7.95 (d, J = 8.8 Hz, 4H), 7.76 (d, J = 7.6 Hz, 4H), 6.76 (d, J = 8.4 Hz, 4H), 6.68 (d, J = 8.0 Hz, 4H), 3.40 (q, J = 7.6 Hz, 8H), 3.05 (s, 12H), 1.20 (t, J = 7.2 Hz, 12H).

13C

NMR (100 MHz, CDCl3) δ (ppm): 155.14, 150.66, 149.25,

143.81, 140.68, 132.78, 119.84, 116.92, 111.29, 110.12, 106.34, 44.34, 40.22, 29.57, 12.77. 19F NMR (376.5 MHz, CDCl3): δ (ppm) = -130.84 (q, 2F). MALDI-TOF-MS m/z: 883.27. Water-soluble B-3 NPs (ICG NPs) were acquired following previous report.51 The solution of B-3 (ICG) (including 2.0 mg B-3 (ICG), 5.0 mg F108, 2 mL THF) was added into the aqueous solution of DSPE−mPEG5000 (15.0 mg in 10 mL H2O) under sonication (180 W) for 2 min. THF was remove by blowing the surface of solution with nitrogen at 45 ºC, then the blue solution was centrifuged with a centrifugal-filter (MWCO = 100 kDa) and washed with PBS (pH = 7.4) for several times. The final products were obtained for the following experiments. The linear relationship of concentration vs the maximal absorption of B-3 in DMSO was measured. 100 μL of B-3 NPs solutions was frozen drying. Then we got the absorption of dry B-3 NPs in 100 μL DMSO. At last, the final concentration of B-3 NPs


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solution was acquired as 5.0 × 10−4 mol L−1 referring to the related linear relationship of concentration vs absorption.

ASSOCIATED CONTENT The MOLDI−TOF−MS, 1H NMR, and

13C

NMR spectra; PL and UV−vis absorption

spectra; Cytotoxicity experiments of B-3 NPs in vitro and in vivo. The Supporting Information can be acquired on the website (http://pubs.acs.org).

AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] *E-mail: [email protected] *E-mail: [email protected] Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Notes The authors declare no competing financial interest.

ACKNOWLEDGMENT This work was supported by the National Funds for Distinguished Young Scientists (61825503), National Natural Science Foundation of China (51473078 and 21671108), National Program for Support of Top-Notch Young Professionals, Scientific and



Technological Innovation Teams of Colleges and Universities in Jiangsu Province (TJ215006), the Open Research Fund of State Key Laboratory of Bioelectronics, Southeast University, and Priority Academic Program Development of Jiangsu Higher Education Institutions (YX03001).


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Scheme 1. (a) The mechanism of intramolecular photoinduced electron transfer and heavy atom effects for enhanced photothermal conversion and singlet oxygen generation. (b) Schematic illustration of the theranostic nanomedicine based on B-3 NPs.



Figure 1. (a) UV−vis absorption and (b) emission spectra of B-1, B-2 and B-3 in DMF (10 μM, λex = 635 nm). (c) Temperature rise of B-1, B-2 and B-3 in DMF (20 μM, 660 nm, 5 min, 0.5 W cm−2), respectively. The starting temperature was 20 oC. (d) Timedependent absorption of DPBF only or its mixture with B-1, B-2 and B-3 at 412 nm under different irradiation time (808 nm, 0.5 W cm−2), respectively.


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Figure 2. (a) Representative TEM image and DLS results of the B-3 NPs in PBS. (b) Absorption spectra of B-3 (10 μM) in DMSO solution (red) and the B-3 NPs (10 μM) in PBS (pH = 7.4) (black). (c) Temperature rise of B-3 NPs in PBS (pH = 7.4) solutions vs concentrations (808 nm, 5 min, 0.5 W cm−2), respectively. (d) Absorption of ADMA (30 μM) with B-3 NPs (10 μM) and (insert) the characteristic absorption of ADMA vs irradiation time in PBS (pH = 7.4), respectively.



Figure 3. Stability of B-3 NPs. (a) I/I0 vs different irradiation time. I and I0 were the maximal absorption of B-3 NPs, ICG NPs, ICG in PBS before and after irradiation (808 nm, 0.5 W cm−2), respectively. Inset: The color of B-3 NPs, ICG NPs, ICG solution in different irradiation time, respectively. (b) Antiphotobleaching and photostability of B-3 NPs, ICG and ICG NPs (20 μM) under irradiation (808 nm, 0.5 W cm−2) during circles of heating−cooling processes. ΔΤn/ΔΤ0 was the maximal temperature change of B-3 NPs, ICG and ICG NPs of the different circles of heating-cooling processes. (c) ApH/ApH = 7.0 vs different pH solutions. ApH and ApH = 7.0 were the absorption at 848 nm in various pH solutions. (d) I/I0 vs RONS (ONOO− and H2O2). I and I0 were the maximal absorption of B-3 NPs, ICG NPs and ICG in PBS solutions in the presence and absence of RONS, respectively.


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Figure 4. (a) Relative viability of Hela and 3T3 cells incubated with various concentrations of B-3 NPs, respectively. (b) Subcellular localization of ROS generated during B-3 NPs (20 μM) -mediated PDT by DCFH-DA staining (808 nm, 0.5 W cm−2, 5 min). All the images shared the same scale bar of 30 μm. Images were taken at 25 oC. (c) Relative viability of cells incubated with PBS, B-3 NPs (20 μM), B-3 NPs (20 μM) under hypoxia, B-3 NPs (20 μM) plus VC, respectively, and then treated with irradiation of different laser power, respectively (808 nm, 5 min).



Figure 5. (a) Flow cytometry quantification of annexin V-FITC and PI-labeled Hela cells treated with B-3 NPs without irradiation, B-3 NPs under hypoxia and irradiation, B-3 NPs under irradiation, B-3 NPs plus VC and irradiation, respectively (20 μM, 808 nm, 0.5 W cm−2, 5 min). (b) Confocal fluorescence images of FITC/PI stained Hela cells incubated with 20 μM of B-3 NPs or not, and then treated with irradiation of an 808 nm (0.5 W cm−2) laser for 5 min, respectively. All the images shared the same scale bar of 120 μM. Images were taken at 25 oC.


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Figure 6. (a) Fluorescence imaging of mice before and after intravenous injection of B-2 NPs (150 µL, 200 µM) in different time. (b) Infrared thermograph of the tumor mice intravenously injected with B-3 NPs (150 µL, 200 µM) or not for 4 h under an 808 nm laser irradiation at 0.5 W cm−2 for 5 min, and (c) their corresponding temperature elevation at tumor region. (d) DCFH staining of tumor sections from the mice intravenously injection with B-3 NPs at 4 h post-injection in the absence or presence of VC under irradiation or not. All the images shared the same scale bar of 120 μm. Images were taken at 25 oC.



Figure 7. Photothermal therapy in vivo. (a) The tumor size and (b) body weight of Hela tumor-bearing mice with various treatments during therapy, respectively. (c) Representative photos of Hela tumor mice at different days after various treatments, respectively. (d) H&E staining of tumor sections obtained from the mice injected with B3 NPs or PBS in the absence or presence of VC under irradiation or not. All the images shared the same scale bar of 300 μm. Images were taken at 25 oC.


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REFERENCES (1)

Shpaisman, N.; Sheihet, L.; Bushman, J.; Winters, J.; Kohn, J. One-Step Synthesis of Biodegradable Curcumin-Derived Hydrogels as Potential Soft Tissue Fillers after Breast Cancer Surgery. Biomacromolecules 2012, 13, 2279–2286.

(2)

White, H. J. Experimental Chemotherapy. Volume III. Chemotherapy of Bacterial Infections. Part II. Chemotherapy of Fungal Infections. Chemotherapy of Rickettsial and Viral Infections. J. Am. Chem. Soc. 1965, 87, 1825–1826.

(3)

Xiao, Q.; Zheng, X.; Bu, W.; Ge, W.; Zhang, S.; Chen, F.; Xing, H.; Ren, Q.; Fan, W.; Zhao, K.; Hua, Y.; Shi, J. A Core/Satellite Multifunctional Nanotheranostic for in Vivo Imaging and Tumor Eradication by Radiation/Photothermal Synergistic Therapy. J. Am. Chem. Soc. 2013, 135, 13041–13048.

(4)

Lv, G.; Guo, W.; Zhang, W.; Zhang, T.; Li, S.; Chen, S.; Eltahan, A.; Wang, D.; Wang, Y.; Zhang, J.; Wang, P. C.; Chang, J.; Liang, X. Near-Infrared Emission CuInS/ZnS Quantum

Dots:

All-in-One

Theranostic

Nanomedicines

with

Intrinsic

Fluorescence/Photoacoustic Imaging for Tumor Phototherapy. ACS Nano 2016, 10, 9637–9645. (5)

Miao, Q.; Xie, C.; Zhen, X.; Lyu, Y.; Duan, H.; Liu, X.; Jokerst, J. V.; Pu, K. Molecular Afterglow Imaging with Bright, Biodegradable Polymer Nanoparticles. Nat. Biotechnol. 2017, 35, 1102-1110.

(6)

Xie, C.; Zhen, X.; Miao, Q.; Lyu, Y.; Pu, K. Self-Assembled Semiconducting Polymer Nanoparticles for Ultrasensitive Near-Infrared Afterglow Imaging of Metastatic Tumors. Adv. Mater. 2018, 30, 1801331.



(7)

Jiang, Y.; Pu, K. Multimodal Biophotonics of Semiconducting Polymer Nanoparticles. Acc. Chem. Res. 2018, 51, 1840−1849.

(8)

Rosenblum, D.; Joshi, N.; Tao, W.; Karp, J. M.; Peer, D. Progress and Challenges Towards Targeted Delivery of Cancer Therapeutics. Nat. Commun. 2018, 9, 1410.

(9)

Li, J.; Pu, K. Development of Organic Semiconducting Materials for Deep-Tissue Optical Imaging, Phototherapy and Photoactivation. Chem. Soc. Rev. 2019, DOI: 10.1039/C8CS00001H.

(10)

Lyu, Y.; Fan, Y.; Miao, Q.; Zhen, X.; Ding, D.; Pu, K. Intraparticle Molecular Orbital Engineering of Semiconducting Polymer Nanoparticles as Amplified Theranostics for in Vivo Photoacoustic Imaging and Photothermal Therapy. ACS Nano 2016, 10, 4472–4481.

(11)

Lyu, Y.; Zeng, J.; Jiang, Y.; Zhen, X.; Wang, T.; Qiu, S.; Lou, X.; Gao, M.; Pu, K. Enhancing Both Biodegradability and Efficacy of Semiconducting Polymer Nanoparticles for Photoacoustic Imaging and Photothermal Therapy. ACS Nano 2018, 12, 1801–1810.

(12)

Zhao, X.; Yang, C.; Chen, L.; Yan, X. Dual-Stimuli Responsive and Reversibly Activatable Theranostic Nanoprobe for Precision Tumor-Targeting and FluorescenceGuided Photothermal Therapy. Nat. Commun. 2017, 8, 14998.

(13)

Jung, H. S.; Verwilst, P.; Sharma, A.; Shin, J.; Sessler, J. L.; Kim, J. S. Organic Molecule-Based Photothermal Agents: An Expanding Photothermal Therapy Universe. Chem. Soc. Rev. 2018, 47, 2280–2297.


Page 32 of 39

Page 33 of 39 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


(14)

Lv, W.; Zhang, Z.; Zhang, K. Y.; Yang, H.; Liu, S.; Xu, A.; Guo, S.; Zhao, Q.; Huang, W. A Mitochondria-Targeted Photosensitizer Showing Improved Photodynamic Therapy Effects under Hypoxia. Angew. Chem., Int. Ed. 2016, 55, 9947–9951.

(15)

Lv, W.; Xia, H.; Zhang, K. Y.; Chen, Z.; Liu, S.; Huang, W.; Zhao, Q. PhotothermalTriggered Release of Singlet Oxygen from an Endoperoxide-Containing Polymeric Carrier for Killing Cancer Cells. Mater. Horiz. 2017, 4, 1185–1189.

(16)

Poinard, B.; Neo, S. Z. Y.; Yeo, E. L. L.; Heng, H. P. S.; Neoh, K. G.; Kah, J. C. Y. Polydopamine Nanoparticles Enhance Drug Release for Combined Photodynamic and Photothermal Therapy. ACS Appl. Mater. Interfaces, 2018, 10, 21125–21136.

(17)

Zhou, Z.; Song, J.; Nie, L.; Chen, X. Reactive Oxygen Species Generating Systems Meeting Challenges of Photodynamic Cancer Therapy. Chem. Soc. Rev. 2016, 45, 6597–6626.

(18)

Tsien, R. Y. Constructing and Exploiting the Fluorescent Protein Paintbox. Angew. Chem. Int. Ed. 2009, 48, 5612–5626.

(19)

Mena, M. A.; Treynor, T. P.; Mayo, S. L.; Daugherty, P. S. Blue Fluorescent Proteins with Enhanced Brightness and Photostability from a Structurally Targeted Library. Nat. Biotechnol. 2006, 24, 1569–1571.

(20)

Hong, G.; Diao, S.; Antaris, A. L.; Dai, H. Carbon Nanomaterials for Biological Imaging and Nanomedicinal Therapy. Chem. Rev. 2015, 115, 10816–10906.



(21)

Page 34 of 39

Razansky, D.; Distel, M.; Vinegoni, C.; Ma, R.; Perrimon, N.; Köster, R. W.; Ntziachristos, V. Multispectral Opto-Acoustic Tomography of Deep-Seated Fluorescent Proteins in Vivo. Nat. Photon. 2009, 3, 412–417.

(22)

Cai, Y.; Liang, P.; Tang, Q.; Yang, X.; Si, W.; Huang, W.; Zhang, Q.; Dong, X. Diketopyrrolopyrrole−Triphenylamine Organic Nanoparticles as Multifunctional Reagents for Photoacoustic Imaging-Guided Photodynamic/Photothermal Synergistic Tumor Therapy. ACS Nano 2017, 11, 1054–1063.

(23)

Kotagiri, N.; Sudlow, G. P.; Akers, W. J.; Achilefu, S. Breaking the Depth Dependency of Phototherapy with Cerenkov Radiation and Low-Radiance-Responsive Nanophotosensitizers. Nat. Nanotechnol. 2015, 10, 370−379.

(24)

Chen, D.; Tang, Q.; Zou, J.; Yang, X.; Huang, W.; Zhang, Q.; Shao, J.; Dong, X. pHResponsive PEG–Doxorubicin-Encapsulated Aza-BODIPY Nanotheranostic Agent for Imaging-Guided Synergistic Cancer Therapy. Adv. Healthcare Mater. 2018, 7, 1701272.

(25)

Ye, S.; Rao, J.; Qiu, S.; Zhao, J.; He, H.; Yan, Z.; Yang, T.; Deng, Y.; Ke, H.; Yang, H.; Zhao, Y.; Guo, Z.; Chen, H. Rational Design of Conjugated Photosensitizers with Controllable Photoconversion for Dually Cooperative Phototherapy. Adv. Mater. 2018, 30, 1801216.

(26)

Huang,

L.;

Gao,

Z.;

Han,

G.

Photoswitchable

Near-Infrared-Emitting

Borondipyrromethene (BODIPY) Nanoparticles. Part. Part. Syst. Charact. 2017, 34, 1700223.


Page 35 of 39 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


(27)

Li, L.; Chen, C.; Liu, H.; Fu, C.; Tan, L.; Wang, S.; Fu, S.; Liu, X.; Meng, X.; Liu, H. Multifunctional Carbon–Silica Nanocapsules with Gold Core for Synergistic Photothermal and Chemo-Cancer Therapy under the Guidance of Bimodal Imaging. Adv. Funct. Mater. 2016, 26, 4424.

(28)

Cui, H.; Hu, D.; Zhang, J.; Gao, G.; Chen, Z.; Li, W.; Gong, P.; Sheng, Z.; Cai, L. Gold Nanoclusters–Indocyanine Green Nanoprobes for Synchronous Cancer Imaging, Treatment, and Real-Time Monitoring Based on Fluorescence Resonance Energy Transfer. ACS Appl. Mater. Interfaces 2017, 9, 25114–25127.

(29)

Lin, J.; Wang, S.; Huang, P.; Wang, Z.; Chen, S.; Niu, G.; Li, W.; He, J.; Cui, D.; Lu, G.; Chen, X.; Nie, Z. Photosensitizer-Loaded Gold Vesicles with Strong Plasmonic Coupling Effect for Imaging-Guided Photothermal/Photodynamic Therapy. ACS Nano 2013, 7, 5320–5329.

(30)

Jin, Q.; Liu, J.; Zhu, W.; Dong, Z.; Liu, Z.; Cheng, L. Albumin-Assisted Synthesis of Ultrasmall FeS2 Nanodots for Imaging-Guided Photothermal Enhanced Photodynamic Therapy. ACS Appl. Mater. Interfaces 2018, 10, 332–340.

(31)

Yuan, L.; Lin, W.; Zheng, K.; He, L.; Huang, W. Far-Red to Near Infrared AnalyteResponsive Fluorescent Probes Based on Organic Fluorophore Platforms for Fluorescence Imaging. Chem. Soc. Rev. 2013, 42, 622–661.

(32)

Sun, W.; Guo, S.; Hu, C.; Fan, J.; Peng, X. Recent Development of Chemosensors Based on Cyanine Platforms. Chem. Rev. 2016, 116, 7768–7817.



(33)

Chatterjee, T.; Srinivasan, A.; Ravikanth, M.; Chandrashekar, T. K. Smaragdyrins and Sapphyrins Analogues. Chem. Rev. 2017, 117, 3329−3376.

(34)

Zhang, S.; Guo, W.; Wei, J.; Li, C.; Liang, X.; Yin, M. Terrylenediimide-Based Intrinsic Theranostic Nanomedicines with High Photothermal Conversion Efficiency for Photoacoustic Imaging-Guided Cancer Therapy. ACS Nano 2017, 11, 3797−3805.

(35)

Qi, J.; Fang, Y.; Kwok, R. T. K.; Zhang, X.; Hu, X.; Lam, J. W. Y.; Ding, D.; Tang, B. Highly Stable Organic Small Molecular Nanoparticles as an Advanced and Biocompatible Phototheranostic Agent of Tumor in Living Mice. ACS Nano 2017, 11, 7177−7188.

(36)

Zheng, M.; Zhao, P.; Luo, Z.; Gong, P.; Zheng, C.; Zhang, P.; Yue, C.; Gao, D.; Ma, Y.; Cai, L. Robust ICG Theranostic Nanoparticles for Folate Targeted Cancer Imaging and Highly Effective Photothermal Therapy. ACS Appl. Mater. Interfaces 2014, 6, 6709−6716.

(37)

Tang, Q.; Xiao, W.; Huang, C.; Si, W.; Shao, J.; Huang, W.; Chen, P.; Zhang, Q.; Dong, X. pH-Triggered and Enhanced Simultaneous Photodynamic and Photothermal Therapy Guided by Photoacoustic and Photothermal Imaging. Chem. Mater. 2017, 29, 5216–5224.

(38)

Bandi, V.; Gobeze, H. B.; D’Souza, F. Ultrafast Photoinduced Electron Transfer and Charge Stabilization in Donor–Acceptor Dyads Capable of Harvesting Near-Infrared Light. Chem. Eur. J. 2015, 21, 11483–11494.


Page 36 of 39

Page 37 of 39 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


(39)

Li, H.; Zhang, P.; Smaga, L. P.; Hoffman, R. A.; Chan, J. Photoacoustic Probes for Ratiometric Imaging of Copper(II). J. Am. Chem. Soc. 2015, 137, 15628−15631.

(40)

Tian, J.; Zhou, J.; Shen, Z.; Ding, L.; Yu, J.; Ju, H. A pH-Activatable and AnilineAubstituted Photosensitizer for Near-Infrared Cancer Theranostics. Chem. Sci. 2015, 6, 5969–5977.

(41)

Lu, H.; Mack, J.; Yang, Y.; Shen, Z. Structural Modification Strategies for the Rational Design of Red/NIR Region BODIPYs. Chem. Soc. Rev. 2014, 43, 4778–4823.

(42)

Ge, Y.; O’Shea, D. F. Azadipyrromethenes: from Traditional Dye Chemistry to Leading Edge Applications. Chem. Soc. Rev. 2016, 45, 3846–3864.

(43)

Hendriks, K. H.; Li, W.; Wienk, M. M.; Janssen, R. A. J. Small Bandgap Semiconducting Polymers with High Near-Infrared Photoresponse. J. Am. Chem. Soc. 2014, 136, 12130−12136.

(44)

Escudero, D. Revising Intramolecular Photoinduced Electron Transfer (PET) from First-Principles. Acc. Chem. Res. 2016, 49, 1816−1824.

(45)

Xu, Y.; Feng, T.; Yang, T.; Wei, H.; Yang, H.; Li, G.; Zhao, M.; Liu, S.; Huang, W.; Zhao, Q. Utilizing Intramolecular Photoinduced Electron Transfer to Enhance Photothermal Tumor Treatment of Aza-BODIPY-Based Near-Infrared Nanoparticles. ACS Appl. Mater. Interfaces 2018, 10, 16299−16307.

(46)

Zou, J.; Yin, Z.; Ding, K.; Tang, Q.; Li, J.; Si, W.; Shao, J.; Zhang, Q.; Huang, W.; Dong, X. BODIPY Derivatives for Photodynamic Therapy: Influence of Configuration versus Heavy Atom Effect. ACS Appl. Mater. Interfaces 2017, 9, 32475−3248.



(47)

Page 38 of 39

Balsukuri, N.; Lone, M. Y.; Jha, P. C.; Mori, S.; Gupta, I. Synthesis, Structure, and Optical

Studies

of

Donor–Acceptor-Type

Near-Infrared

(NIR)

Aza–Boron-

Dipyrromethene (BODIPY) Dyes. Chem. Asian J. 2016, 11, 1572–1587. (48)

Guo, Z.; Zou, Y.; He, H.; Rao, J.; Ji, S.; Cui, X.; Ke, H.; Deng, Y.; Yang, H.; Chen, C.; Zhao, Y.; Chen, H. Bifunctional Platinated Nanoparticles for Photoinduced Tumor Ablation. Adv. Mater. 2016, 28, 10155–10164.

(49)

He, H.; Ji, S.; He, Y.; Zhu, A.; Zou, Y.; Deng, Y.; Ke, H.; Yang, H.; Zhao, Y.; Guo, Z.; Chen, H. Photoconversion-Tunable Fluorophore Vesicles for Wavelength-Dependent Photoinduced Cancer Therapy. Adv. Mater. 2017, 29, 1606690.

(50)

Yang, K.; Wan, J.; Zhang, S.; Zhang, Y.; Lee, S.; Liu, Z. In Vivo Pharmacokinetics, Long-Term Biodistribution, and Toxicology of PEGylated Graphene in Mice. ACS Nano 2011, 5, 516−522.

(51)

Yin, C.; Zhen, X.; Zhao, H.; Tang, Y.; Ji, Y.; Lyu, Y.; Fan, Q.; Huang, W.; Pu, K. Amphiphilic Semiconducting Oligomer for Near-Infrared Photoacoustic and Fluorescence Imaging. ACS Appl. Mater. Interfaces 2017, 9, 12332−12339.


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Highly Stable and Multifunctional Aza-BODIPY-Based

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