Porous OrganosilicaâFe3O4

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Template-Free Synthesis of Hollow/Porous OrganosilicaFe3O4 Hybrid Nanocapsules Towards MRIGuided High Intensity Focused Ultrasound Therapy Ming Ma, Fei Yan, Minghua Yao, Zijun Wei, Dongliang Zhou, Heliang Yao, Hairong Zheng, Hangrong Chen, and Jianlin Shi ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.6b10370 • Publication Date (Web): 24 Oct 2016 Downloaded from http://pubs.acs.org on October 26, 2016

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ACS Applied Materials & Interfaces

Template-Free Synthesis of Hollow/Porous Organosilica-Fe3O4 Hybrid Nanocapsules Towards MRI-Guided High Intensity Focused Ultrasound Therapy Ming Ma,1,‡ Fei Yan,2,‡ Minghua Yao,3 Zijun Wei,2 Dongliang Zhou,2 Heliang Yao,1 Hairong Zheng,2,* Hangrong Chen,1,* and Jianlin Shi1

[1] State Key Lab of High Performance Ceramic and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences,1295 Dingxi Road, Shanghai 200050, P. R. China; [2] Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Ave., Shenzhen 518055, P. R. China; [3] Department of Ultrasound in Medicine, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Yanchangzhong Road, Shanghai 200072, P. R. China KEYWORDS: hollow mesoporous nanoparticle, organosilica, theranostic, contrast agent, HIFU

ABSTRACT: Entirely differing from the common templating-based multistep strategy in fabricating multifunctional hollow mesoporous silica nanoparticles (HMSNs), a facile and template-free

synthetic

strategy

has

been

established

ACS Paragon Plus Environment

in

constructing

a

unique


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hollow/mesoporous organosilica nanocapsule concurrently encapsulating both isopentyl acetate (PEA) liquid and superparamagnetic iron oxides inside (denoted as PEA@OSNCs). This novel material exhibits ultrasmall and uniform particle size (~82 nm), high surface area (~534 m2 g-1) and excellent colloidal stability in aqueous solution. The oil phase PEA with relatively low boiling point (142 oC) and high volatility not only plays a crucial role in the formation of large hollow cavity from the viewpoint of structural design, but also enables the PEA@OSNCs as an efficient enhancement agent in high intensity focused ultrasound (HIFU) therapy. Moreover, the unique satellite-like distribution of Fe3O4 nanoparticles (NPs) on the organosilica shell offered an excellent magnetic resonance imaging (MRI) contrast capability of PEA@OSNCs in vitro and in vivo. More importantly, such novel theranostic agent has favorable biosafety, which is very promising for future clinical application in MRI-guided HIFU therapy.

1. Introduction

Theranostic nanomedicine is based on the concept of simultaneously delivering both therapeutics and diagnosis agent into disease region through a single nanoplatform, which has received a great deal of research interests over recent decades.1-6 These nanomedicines are capable of improving the anticancer effect by controlling the release of different therapeutic agents, as well as providing real-time contrast imaging to ascertain the lesion location and monitoring the therapeutic responses to medication, which are also anticipated to play a highly important role in the progress of personalized medicine.7-11 However, in comparison to the single-modal contrast agent (CAs) or therapeutic agents, the development of an ideal ACS Paragon Plus Environment

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novel nano-theranostic paradigm is of still challenge in structure manipulation, since it demands to highly integrate multiple chemical and physical composition into one stable nanosystem in a small size below 200 nm.12 Meanwhile, many reported approaches have not achieved clinical success owing to biosafety issues, complex preparation and diminished theranostic performance. Therefore, significant advances in materials science and nanotechnology are urgently required towards successful development of theranostic NPs for clinical applications.

HMSNs are regarded as one of the most clinically potential inorganics NPs for drug delivery application owing to their unique mesoporous structure, large void space, high surface area and favorable biocompatibility.13-17 Previously, the HMSNs have been fabricated by self-assembly and condensation of silica precursors on the heterogeneous liquid phases including oil-in-water and water-in-oil microemulsions.18, 19 As these soft templates generally present low stability and poor dispersity in reaction solution, the prepared hollow structures are often heavily aggregated and ill-defined in morphology. To overcome above problems, hard templating methods have been employed to construct mono-dispersed HMSNs by using polystyrene spheres, CaCO3 or silica NPs as sacrificial core templates.20-22 Moreover, a series of multifunctional HMSNs, such as Au@meso-SiO2 hollow nanospheres23, rattle-type Fe3O4@meso-SiO2 NPs24 and mesoporous silica-coated hollow MnO nanocomposties25 were also synthesized with similar templating approaches. However, the current synthetic strategies generally require multistep procedures as well as protective polymers or etching agents for core elimination, which are less efficient and tedious for large-scale production.26



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Furthermore, the obtained HMSNs always suffer from the potential cytotoxic effect owing to the residues of templates in the final products.27,

28

Therefore, seeking for a facile and

template-free strategy for preparation of HMSNs has been urgently recommended and encouraged. More importantly, it is highly valuable to construct an “ideal” HMSN, satisfying the multiple basic requirements for clinical translation, including sub-100 nm size control, well-defined size distribution and good biocompatibility.29

HIFU therapy is a kind of promising non-invasive cancer therapeutic approach using focused ultrasound to ablate the tumor tissue by the combined mechanical and thermal effects.30 Nevertheless, the HIFU ablation of deep seated tumor generally suffers from the low energy deposition owing to the rapid energy decrement along ultrasound pathway, thus leading to an unsatisfactory ablation effect.31 Meanwhile, seeking for an efficient imaging strategy to realize the accurate spatial positioning of tumour therapeutic target for HIFU by clinically diagnostic protocols (MRI, ultrasound imaging, etc.) is still a great challenge in current stage. In order to overcome above typical challenges, a manganese oxide (MnOx) NPs-embedded HMSN nanoagent (MnOx@HMSNs) has been designed and prepared recently to be used in MRI-guided HIFU therapy.32 Such integrated nanosystem was shown to combine both merits of MnOx NPs embedded in the porous channels for contrast-enhanced MRI and large hollow cavity for delivery of hydrophobic phase-change liquid (PCL) towards enhancing HIFU therapeutic efficacy. Although conceptually impressive, concerns remain to the potential toxicity of Mn ions including neurological disorder and manganism.33 Moreover, to load PCL into HMSNs based carriers (pure HMSNs34, MnOx@HMSNs32, etc.), a vacuum


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assisted infusion process is generally employed to enable the PCL diffusing into the hollow cavity by the driving force of gas pressure. However, the obtained nanocomposites generally suffer from poor dispersal stability because of the inevitable adsorption of hydrophobic PCL on the outer surface of HMSNs, which greatly limit their therapeutic outcomes. Thus, it is highly desired to fabricate a HMSNs based HIFU synergistic agent with PCL only locating in the inner pores and/or interior cavity, which is beneficial for stable delivery in blood circulation system as well as increased particles accumulation in tumor.

Considering the above circumstances, herein, we report a facile and template-free synthetic strategy to successfully formulate an organosilica nanocapsule concurrently encapsulating both a typical HIFU synergistic liquid PEA and MRI contrast nanoagents Fe3O4 NPs (designated as PEA@OSNCs). As an emerging material, the newly designed nanocomposite exhibits a novel hollow-core/satellite shell structure, with PEA liquid encapsulated in the hollow cavity and numerous superparamagnetic NPs (Fe3O4) embedded onto the shell, like satellites surrounding the PEA core. More intriguingly, the PEA@OSNC is able to serve as an efficient theranostic nanoagent both in vitro and in vivo, simultaneously rendering high contrast MR imaging and significantly enhancing tumor ablation under HIFU irradiation, which is of great potential for future MRI guided noninvasive HIFU synergistic therapy.

2. Results and Discussions

2.1 Synthesis and physical characterization of PEA@OSNCs



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The proposed design of the multifunctional hybrid NPs PEA@OSNCs is shown in Scheme 1. The fabrication of PEA@OSNCs includes a surfactant-free emulsification process of the oil phase PEA/3-(trimethoxysilyl) propyl methacrylate (TPM) mixture in positively charged Fe3O4 NPs aqueous suspension, followed by a radical polymerization of TPM (Scheme 1A). Inspired by the previously reported formation mechanism of pickering emulsion,35 it is proposed that the positive charged Fe3O4 NPs will spontaneously lower the interfacial tension between water and oil phase by a self-assembly process at the liquid-liquid interface, thus leading to the spontaneous evolution of the phase-separated oil-water mixture into a nanoemulsion. Therefore, a thermodynamically stable “oil-in-water” nanoemulsion with PEA/TPM oil phase surrounded by numerous Fe3O4 NPs is anticipated to be obtained during emulsification process. The radical polymerization of TPM could further strengthen the integral stability of nanoemulsion by forming polymerized organosilica molecular skeleton (shown in Scheme 1B), enabling PEA to be stably sealed inside the synthetic particle. Importantly, the successful integration of Fe3O4 NPs and PEA in one nano-platform by above technique can be used to simultaneously enhance both MRI and HIFU performance (Scheme 1B).

TEM image shows that the obtained PEA@OSNCs possess hollow structure with mean diameter of about 82 nm and shell thickness of about 20 nm (Figure 1A). Meanwhile, both the apparent imaging contrast on the particle shell (Figure 1B) and the corresponding Fe element mapping profile (Figure 1C) indicate that the numerous Fe3O4 NPs with the particle size below 10 nm in diameter are uniformly distributed as satellites surrounding the hollow sphere.


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Interestingly, we could hardly detect any isolated Fe3O4 NPs outside organosilica spheres from the SEM image (Figure 1D), suggesting that all the Fe3O4 NPs have steadily anchored into the organosilica shell. Importantly, the TEM image of NPs with low magnification (Figure S1) shows high uniformity of PEA@OSNCs in regarding to particle size, monodispersity as well as hollow-core/satellite shell morphology. These hollow particles have a high specific surface area of 534 m2 g-1 as confirmed by the nitrogen adsorption-desorption analysis (Figure 1E, S2). Meanwhile, the sample exhibits typical IV isotherms with a hysteresis loop in the wide pressure range from 0.45 to 0.8, suggesting the existence of the mesoporous structure in the shell (Figure 1E). Considering the large number of open pores present in PEA@OSNCs, it is believed that the PEA can rapidly diffuse outwards via a phase-change process upon the hyperthermia treatments, e.g. HIFU and radio frequency irradiation. Furthermore, FTIR spectrum of the dried PEA@OSNCs (Figure S3) indicates the strong specific peaks at 2961, 1726 and 1306 cm−1, which are well assigned to CH-, C=O, and C-COO-organic

groups

in

organosilica

framework,

respectively.

Meanwhile,

the

PEA@OSNCs exhibit relatively strong negative surface charge with zeta potential of -30.4 mV, which is mainly ascribed to the presence of silanol groups and acetate groups on the particle surface. More encouragingly, this facile synthetic process can be easily scaled up from 100 mg to several grams in one batch just by increasing the reactant amount and applying a larger glass container, which is of great advantage in industrial scale production.

It is known that the MSNs without surface polymer modification generally suffer from the poor colloidal stability against aqueous solution, which is considered as one of the major



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barriers of MSNs for clinical application.36 Interestingly, very different from the traditional silica based NPs, the PEA@OSNCs suspension presents almost the same narrow hydrodynamic size distribution in deionized water and saline solution with mean hydrodynamic diameter of 89.5 nm and 89.9 nm, respectively (Figure 1F, S4). Also, the colloidal stability of the PEA@OSNCs could be maintained for at least two months in aqueous solution without noticeable particle precipitation (Figure S4B). Such small hydrodynamic size and high dispersal stability are considered to be acceptable for systemic administration.37, 38 To verify this, Si element biodistribution in the tumor-bearing Balb/c mouse after intravenous administration of PEA@OSNCs (10 mg per kg of mouse) was investigated, and the result showed that about 3.6 wt% of PEA@OSNCs was accumulated in tumor region at 1h, revealing satisfied passive accumulation within tumors (Figure S5)

38

.

Such high performance of PEA@OSNCs in both dispersity and stability mainly results from the concurrent contributions of uniform particle size and PEA core-related low gravity. More importantly, the employment of organosilane TPM as the silane precursor rather than conventional tetraethyl orthosilicate is considered to significantly decrease the density of surface exposed silanols, thus leading to significant inhibition of hydrogen bond between interfaces and electrostatic absorption of salt ions on particle surface.39

2.2 Structure control and formation mechanism of PEA@OSNCs

It is notable that the PEA and Fe3O4 NPs are not only the basic constituents of PEA@OSNCs for potential theranostic application, but also play critical role in the formation of such distinctive particle structure by serving as indispensable reactants. Firstly, different


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amounts of PEA (0, 0.500, 0.625 and 0.750 mL) mixed with a constant amount of TPM (0.125 mL) were used in the first emulsification process to investigate the effect of PEA usage on the formation of hollow structure. It is found that the PEA@OSNCs with uniform size and well-defined structure can be well obtained when the volume of PEA is fixed at 0.625 mL (Figure 1A). However, when the amount of PEA is increased to 0.750 mL, PEA@OSNCs exhibit much broader size distribution as shown in TEM image (Figure 2A), wherein, many larger particles above 200 nm and smaller ones around 70 nm are found in coexistence, suggesting that these particles are no longer thermodynamically stable when the interfacial tension between oil and water increases to a critical value. In contrast, the reduction in the PEA amount beginning from 0.625 mL leads to obvious decrease of cavity diameter (Figure 2B). It is noting that the nonporous spheres embedded with numerous Fe3O4 NPs could be obtained without adding PEA (Figure S6). Furthermore, it is clearly observed that the nanoemulsion could hardly be formed in the absence of Fe3O4 NPs, and only rapid sedimentation of polymerized-TPM particles with irregular shape are observed after polymerization (Figure 2C). However，the hollow structure of PEA@OSNCs could be clearly found when the mass concentration of Fe3O4 NPs in reaction solution was above 200 µg mL-1 (shown in Figure S7). Moreover, the average number of Fe3O4 NPs embedded on the shell of each OSNC particle was gradually increased with the increment of the addition amount of Fe3O4 NPs (Figure S7). These results confirm that both PEA and Fe3O4 NPs are indispensable for

the

formation

and

stabilization

of

the

nanoemulsions,

hollow-core/satellite shell structure.


yielding

the

final


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Based on the experimental results, the structural transformation of Fe3O4 NPs stabilized TPM/PEA oil nanoemulsion to the final hollow structure of OSNCs can be divided into two stages, as illustrated in Figure 2D. Firstly, the polymerized organosilica outer-layer embedded with numerous Fe3O4 NPs will be formed immediately upon the addition of the initiator KPS, because the outermost TPMs of nanoemulsion are earlier involved in the radical polymerization compared to that of the interior ones. Afterwards, the polymerization will continuously occur in the sealed liquid phase where the free TPMs tend to gradually diffuse outwards from center and take part in the shell formation, thus leaving a cavity containing PEA. Considering the presence of organic moieties in the framework of polymerized TPM, the hydrophobic PEA is likely to be stably encapsulated inside hollow void space in the aqueous solution under mild condition.

2.3 Biosafety evaluation

The biosafety behavior of the PEA@OSNCs including cell cytotoxicity and in vivo toxicity for healthy balb/c mice was afterwards investigated. The cytotoxicity of PEA@OSNCs was evaluated by both cell counting WST-8 assay and trypan blue exclusion tests on human hepatic immortal cell line HL-7702 and mammary carcinoma cell line 4T1 cells, representing the normal and tumor cells, respectively. It is clearly observed that the sample exhibit negligible cytotoxicity against both cells at concentrations up to 400 µg.mL-1 (Figure S8, S9). Meanwhile, the in vivo hemocompatibility and liver function were evaluated by conducting both blood routine and serum biochemistry tests on the 30th day after receiving the intravenous injection of PEA@OSNCs at the dose of 2 mg per mouse. The hematological


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results (Figure 3A) obtained from the group treated with PEA@OSNCs show no noticeable differences compared to those of the control group injected with saline solution. Meanwhile, no obvious differences of the alanine transaminase (ALT)/aspartate transaminase (AST) ratio was found between the saline (control) and PEA@OSNCs group, which confirms that PEA@OSNCs induce no obvious hepatic toxicity in mice. In addition, hematoxylin-eosin (H&E) stain results reveal that there is no significant pathological tissue damage and inflammatory to the main organs including heart, liver, spleen, lung and kidney at 30th day post injection of PEA@OSNCs (Figure 3B). Thus, the above results confirm that the polymerized organosilica nature and small particle size of PEA@OSNCs could not bring any adverse effect to animal models and are highly favorable for the biomedical applications.

2.4 Magnetic property and MRI contrast capability

It is noted that the X-ray diffraction (XRD) pattern of PEA@OSNCs (Figure S10) is in accordance to the characteristic peaks of magnetite (Fe3O4) with a cubic spinal structure, indicating that PEA@OSNCs could exhibit the similar magnetic property as conventional Fe3O4 NPs.40,

41

Furthermore, the magnetic property of PEA@OSNCs was studied by

vibrating sample magnetometer (VSM) and superconducting quantum interference device (SQUID). Notably, the field-dependent magnetization curve of PEA@OSNCs exhibits a negligible hysteresis loop with the magnetization saturation (MS) value of 42.9 emu g-1 (Figure 4A, S11). Meanwhile, the blocking temperature (Tb), which represents the transfer temperature from superparamagnetism to ferromagnetism, was measured to be about 236 K



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according to the corresponding temperature-dependent magnetization curve (Figure S12), confirming the excellent superparamagnetism of PEA@OSNCs at room temperature.

Moreover, the assessment of PEA@OSNCs as CAs in MRI was conducted on a clinical 3.0 T MRI instrument. The T2-weighted MR phantom images and relaxivity data for PEA@OSNCs at different Fe concentrations shown in Figures 4B and C indicate that the negative contrast increases with the increment of particle concentration. The T2 relaxivity coefficient (r2) value of PEA@OSNC is measured to be 417.0 mM−1s−1 (Figure 2C), which is significantly higher than that of the iron oxide-gold hybrid core-shell nanoparticles (132.2 mM-1 s-1 at 1.5 T magnetic field strength) and clinically used dextran-coated Fe3O4 magnetic nanofluid (133 mM-1 s-1 at 1.5 T magnetic field strength).42 The significant increase of T2 relaxivity value for PEA@OSNCs is mainly attributed to the clustering distribution of numerous Fe3O4 NPs on OSNCs, which is well consistent with previous data of PEOlated Fe3O4@SiO2 and Fe3O4-loaded polymeric micelles 43-45. Furthermore, the in vivo T2-weighted MR imaging capability of PEA@OSNCs was evaluated on a tumor-bearing mouse model. As expected, the tumor shows a remarkably darkened area at the injection site after injection of PEA@OSNCs, and the mean signal intensity is found to have a dramatic decrease from 188 to 52 (Figure 4D). Additionally, the tumor region also becomes markedly dark at 1h post intravenous injection (as shown in Figure S13), ascribed to the significant tumor accumulation of PEA@OSNCs. Thus, both the in vitro and in vivo tumor imaging results confirm that the PEA@OSNCs could be used as ultrasensitive CAs for T2-weighted MRI.

2.5 Enhanced HIFU ablation effect


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The PEA, being in situ sealed in OSNCs during the particle formation, possesses the physical characters including low boiling point, strong volatility and hydrophobicity, which is exactly similar to the previously reported HIFU synergistic liquids including perfluorooctyl bromide (PFOB) and menthol.46,

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Meanwhile, the quantitative result obtained by gas

chromatography–mass spectrometry (GC-MS) shows that the total content of PEA loaded in the PEA@OSNCs is about 5.4×10-2 µL mg-1 (Figure S14), revealing OSNCs can efficiently encapsulate PEA. Furthermore, the release behaviors of PEA for PEA@OSNCs in the absence and the presence of HIFU were investigated as shown in Figure S15. Slow PEA release before HIFU irradiation, with only about 2.4 % PEA released out of PEA@OSNCs in 3 h, was observed as we expected, which further confirmed the hydrophobic PEA could be stably encapsulated inside hollow void space under mild condition. However, after receiving HIFU irradiation at 100 W for 10s, the PEA release amount rapidly increased to about 37.4 %, indicating HIFU could mediate and remarkably accelerate the“liquid to gas” phase-change of PEA. Therefore, it is believed that the PEA@OSNCs can serve as an efficient synergistic nanoagent for HIFU ablation therapy owing to the enhanced cavitation effect by the encapsulated PEA liquid. To prove this, the therapeutic performance of PEA@OSNCs was firstly evaluated on an ex vivo bovine liver model, and compared with both saline solution as control group and organosilica nanosphere (OSNP) as non-PEA containing group (Figure 5A-C). In brief, the three samples were injected into the focused region of bovine liver separately, followed by ultrasound-guided HIFU exposure of a power input of 140 W for 10 s. The grey scale change of focused region under ultrasound imaging, as an in situ evidence reflecting the degree of coagulation necrosis, was recorded before and after HIFU irradiation ACS Paragon Plus Environment


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for each group (Figure 5A). No noticeable ultrasound imaging contrast enhancements were observed after HIFU exposure for both samples injected with saline and OSNPs. In contrast, after receiving HIFU exposure in the presence of PEA@OSNCs, the focused region presented a significant contrast enhancement with a sharp increase of average grey scale from 109 dB to 155 dB. Furthermore, the necrosis volume in every liver sample was also measured after HIFU exposure. Remarkably, the mean necrosis volume of PEA@OSNCs group is determined to be 40.8 mm3 as shown in Figure 5C, which is significantly larger than those of the control group (6.8 mm3) and OSNPs group (7.9 mm3). Such a remarkable increase by about 6 times in the necrosis volume confirms the excellent enhancement effect of PEA@OSNCs on HIFU ablation resulted from the “liquid to gas” phase-change of PEA.

Furthermore, the mouse model xenografted with 4T1 cell line was chosen to study the therapeutic effect of PEA@OSNCs in vivo (as shown in Figure 5D, 5E). The three groups of mice independently received HIFU exposures (power 100 W; duration time: 10 s) after different administrations of: (1) intravenous injection with saline solution (control group); (2) intravenous injection with samples (PEA@OSNCs-iv); (3) intratumor injection with samples (PEA@OSNCs-ih). After HIFU exposure, the necrosis volumes of PEA@OSNCs-iv and PEA@OSNCs-ih group were measured to be 52.3 mm3 and 523.3 mm3, respectively (Figure 5E). Although the ablation effect of PEA@OSNCs via intravenous injection is significantly lower than that of intratumoral injection owing to the largely different intratumoral particle concentrations between two administrations, the ablation volume of PEA@OSNCs-iv group still shows about three times larger than that (12.9 mm3) of the control group (Figure 5E).


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Furthermore, the pathological examinations were carried out by H&E and TUNEL staining to compare the lesion conditions between control and PEA@OSNCs-iv group. As shown in the representative tissue sections stained with H&E (Figure S16), a distinctly larger area of coagulative necrosis as confirmed by a series of cell damages, such as karyopyknosis and karyorrhexis, can be observed in the ablated tumor regions of PEA@OSNCs-iv compared to control group. Meanwhile, the image of TUNEL-stained tumor tissue (Figure S17) in the PEA@OSNCs-iv group shows that a considerable proportion of cell structures completely disappear in the HIFU focused region, further confirming the occurrence of coagulative necrosis in the solid tumor. Both above results indicate that the employment of PEA@OSNCs in HIFU ablation can result in significantly increased coagulative ablation effect against tumor regions, which is of great potential to be an efficient synergistic agent for the HIFU ablation surgery. Moreover, such HIFU synergistic agent could also be in situ observed by MRI for better understanding the accumulation in tumor tissue, thus, the optimal time of HIFU exposure can be easily determined. Therefore, it is believed that this biocompatible PEA@OSNCs with both capabilities of MRI contrast enhancement and efficient HIFU ablation will find a promising prospect in the future application.

3. Conclusion In summary, a unique hollow/porous organosilica nanostructure encapsulating both temperature-responsive PEA liquid and superparamagnetic iron oxide NPs has been successfully constructed through a facile and template-free organosilica emulsion polymerization

strategy.

The

obtained

PEA@OSNCs

have


several

extraordinary


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characteristics over conventional HMSNs based nanosystems, including highly uniform hollow-core/satellite shell structure, ultrasmall particle size (below 100 nm), high surface area (~534 m2g-1) and excellent dispersity in aqueous solution, which could satisfy the basic requirements for further biomedical application. More importantly, the PEA@OSNCs exhibit both favorably high biosafety, as well as enhancement effect in MR imaging and HIFU therapy both in vitro and in vivo, which provide a promising “multiple-function-in-one” theranostic nanoplatform in the future clinical cancer therapy. Overall, it is believed that the structural advantage of these newly developed HMSNs can also be extended towards broader applications including magnetic inductive hyperthermia treatment and magnetic separation, as well as other applications to be explored in the future.


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Scheme 1. A schematic diagram of PEA@OSNC, including its synthesis and theranostic application. Schematic illustration of (A) organsilica emulsion polymerization process; (B) chemical composition and theranostic applications of PEA@OSNCs including (i) HIFU synergistic ablation therapy and (ii) MR contrast imaging.



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Figure 1 Structure characterizations of PEA@OSNCs. (A, B) TEM images of PEA@OSNCs. (C) Fe element mapping corresponding to (B), displaying the distribution of Fe3O4 NPs in the overall structure. (D) SEM image of PEA@OSNCs. (E) The curve of nitrogen adsorption-desorption isotherm for PEA@OSNCs. (F) Hydrodynamic size distributions of PEA@OSNCs dispersed in saline solution. Inset figure: the corresponding photograph of the PEA@OSNCs saline suspension.


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Figure 2 (A, B) TEM images of the NPs prepared using the same concentration of Fe3O4 NPs (3.5 mg mL-1) and different amounts of PEA: (A) 0.750 mL and (B) 0.500 mL. (C) TEM image of NPs prepared without addition of Fe3O4 NPs. (D) Schematic illustration for the structural conversion process from nanoemulsion to hollow structure.


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Figure 3 (A) The haematological and blood biochemical analyses of mice on the 30th day after receiving the intravenous injection of saline solution and PEA@OSNCs at the total dose of 2 mg per mouse model. (B) Images of the H&E-stained tissue sections (heart, liver, spleen, lung and kidney) collected from the mice on the 30th day after receiving the intravenous injection of saline solution and PEA@OSNCs at the total dose of 2 mg per mouse.


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Figure 4 Magnetic property and MR contrast capability of PEA@OSNCs. (A) Field-dependent magnetization curve of OSNCs at room temperature. Absence of hysteresis loop confirms the superparamagnetism of our prepared sample. (B) T2-weighted MR phantom images and (C) plot of inverse transverse relation times (1/T2) versus Fe concentration for OSNCs. (D) In vivo MR imaging of tumor-bearing mice before and after intratumoral injection of PEA@OSNCs suspension. The arrows point the tumor tissue.



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Figure 5 Ex vivo and in vivo studies of the enhancement effect of PEA@OSNCs on HIFU thermal ablation. (A) The ultrasound images at the focus (noted as green circle) of ex vivo bovine liver samples before and after HIFU irradiation for 10 s in presence of 0.5 mL of saline, OSNPs (2 mg mL-1) and PEA@OSNCs (2 mg mL-1). The average grey scale at the focus of each sample is indicated at the bottom right of each image. (B) The photo presents the experimental equipment for ex vivo HIFU ablation. (C) Average value of corresponding ablated volumes after each treatment. Inset: pictures of ablated samples. The white areas represent the necrosis ablation extent of three groups. (D) Schematic diagram of in vivo HIFU ablation on a tumor-bearing mice model. (E) Pictures of tumor tissues after HIFU exposure in the tumor-bearing mice treated with different treatments. The necrosis regions are marked with white ellipse.


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4. Experiment Section Materials Isopentyl acetate (PEA), 3-(trimethoxysilyl) propyl methacrylate (TPM) and potassium persulfate (KPS) were purchased from Sigma-Adlrich. The ammonia solution (25%), hydrochloric acid (36.5%), ferric trichloride (FeCl3), ferrous chloride tetrahydrate (FeCl2·4H2O) and tetramethylammonium solution (25%) were purchased from Sinopharm Chemical Reagent Co., Ltd. Characterizations TEM images were obtained by JEM-2100F electron microscope operating at 200 kV by dipping an ethanol solution on Cu grids. SEM images were obtained using HITACHI S-4800. The UV-vis spectroscopy is performed on a Shimadzu UV-3101PC UV-vis absorption spectrophotometer. Dynamic light scattering was conducted using Nano-ZS90. The PEA amount loaded in the nanocomposite was analyzed on a Network gas chromatograph system (Agilent Technologies, 6890/5973N). Thefourier-transform infrared spectroscopy (FT-IR) analyses

were

carried

out

on

a

Nicolet

7000-C

spectrometer.

Then

itrogen

adsorption-desorption curve were obtained on a Micrometitics Tristar 3000 system. The Brunauer-Emmett-Teller (BET) method was empolyed to measure the specific surface area of porous sample. Meanwhile, the corresponding pore size distribution was measured by the Barrett-Joyner-Halenda (BJH) method. Synthetic procedure 1) Synthesis of positively charged Fe3O4 NPs An aqueous mixture of FeCl3 (40 mL, 6.5 g) and FeCl2·4H2O (4.0 g, dissolved in 10 mL of HCl solution (2 M)) were added to ammonia solution (500 mL, 0.7 M) under the vigorous


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stirring to obtain black precipitate within 5 min. Then, the precipitate were isolated by magnetic decantation and then re-suspended in an aqueous 1 M tetramethylammonium (100 mL). After being stirred for 24 h, the positive charged Fe3O4 NPs were re-collected by magnetic decantation. Finally, the dispersion of positive charged Fe3O4 NPs with concentration of 20 mg mL-1 was obtained by dilution with deionized water. 2) Synthesis of PEA@OSNCs 4 mL of Fe3O4 NPs dispersion (20 mg mL-1) as well as the mixture of PEA (0.625 mL) and TPM (0.125 mL) was successively added into 18 mL of deionized water. The final mass concentration of Fe3O4 NPs in reaction solution was 3.5 mg mL-1. In addition, to understand the effect of PEA amount on the formation of hollow structure, different amount of PEA (0, 0.500 and 0.750 mL) mixed with a constant amount of TPM (0.125 mL) was also employed separately in the first step of emulsification process for comparison. The above solution was gently stirred at 30 oC for 24 h to form brown emulsion. Next, the emulsion was deoxygenated using bubbling nitrogen after transferred to a sealed bottle. The radical polymerization was initialized by adding KPS (10 mg) in the solution using a microsyringe. After that, the reaction was carried out at 70 oC for 6 h under magnetic stirring. The resultant sample (hollow OSNCs encapsulated with PEA liquid) was collected by centrifugation at 13000 rpm, and re-suspended in water solution by shaking or vacuum freeze dried for further characterizations. The OSNPs were fabricated by the same procedure above except that no PEA was added. This sample can be collected by magnetic decantation. 3) Cytotoxicity evaluations against HL-7702 and 4T1 cells


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Cells (HL-7702 and 4T1) were cultivated in Dulbecco’s modified Eagle’s medium (DMEM) containing 10% (v/v) fetal bovine serum, streptomycin (100 µg mL-1) and penicillin (100 units mL-1) in a humidified incubator at 37 °C, 5% CO2. They were firstly seeded in 96-well plate at a density of 2 × 104 cells in 100 µL DMEM for 8 h. Then 100 µL of the DMEM containing different concentrations of PEA@OSNCs (0–400 µg mL-1) were added into each well separately. After co-incubation for 24 h and 48 h, separately, the cell viability was assessed using WST-8 cell proliferation assay. For the trypan blue exclusion test of cell viability, cells are suspended in DMEM containing trypan blue and then enumerated on a counting plate to determine the percentage of cells that have clear cytoplasm (viable cells) versus cells that have blue cytoplasm (nonviable cells). 4) In vivo biosafety evaluation Balb/c mice (6 to 10 week old) were purchased from Guangdong Medical Experimental Animal Center (Guangzhou, China). Animal procedures were conducted following the guidelines of the institutional Animal Care and Use Committee. Balb/c mice were randomly divided into two groups (n=7) to receive the intravenous injection with saline (1 mL) and PEA@OSNCs (2 mg, in 1 mL saline) through tail vein separately. After being fed for 30 days, the mice were sacrificed and the whole blood was collected for biochemical analysis. The haematological and blood biochemical analyses were conducted by JRDUN Biotechnology Co., Ltd.. The profile contains alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine (CREA), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), white blood cells (WBC), red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular hemoglobin concentration (MCHC) and lymphocytes (LYM). Besides, the main organs, including liver, spleen, heart, kidney and lung, were collected and cut into slides for H&E analysis. The H&E analysis was conducted by Wuhan Google biotechnology Co., Ltd..


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5) In vitro and in vivo MR imaging The MR imaging was conducted on a clinical 3.0 T MRI instrument (GE Signa 3.0T) by the sequences as follows: field of view FOV=12 cm2, thickness=4 mm, spacing=0.5 mm, NEX=1, repetition time (TR)=5000 ms, Echo time (TE)=13, 26, 39, 52. The relaxivity value r2 was calculated though the curve fitting of 1/T2 (s-1) versus the Fe concentration (mM). To assess the imaging capability of PEA@OSNCs in vivo, the anesthetized mouse was intratumorally injected with 0.2 mL of PEA@OSNCs (1 mg mL-1) followed by T2-weighted imaging with the same parameters above. For the intravenous injection group, the mice were intravenously injected with 100 µL of 400 µg mL-1 of PEA@OSNCs. At 1h post-injection, the mice were anaesthetized and imaged under MR imaging. 6) Ex vivo evaluation of the HIFU ablation effect The JC HIFU tumor therapy system was applied to evaluate the HIFU ablation effect of each sample. The degassed bovine livers were cut into rectangles (about 10 mm×8 mm×5 mm) and then placed into the tank filled with degassed water. 0.5 mL of saline, OSNPs (2 mg mL-1) and PEA@OSNCs (2 mg mL-1) were separately injected into the focused region of bovine liver, while the ultrasonography was conducted to find the correct position of each sample. Then, HIFU irradiation was carried out for 10 s at the power of 140 W for each sample. The ultrasound images were recorded before and after HIFU exposure, and the corresponding grey scale values were measured by software GrayVal 1.0 (Chongqing Haifu Technology). Meanwhile, the ablation volume was measured and calculated following the equation: V=π×L×W2/6 (L: maximum length (mm); W: width (mm)). 7) In vivo evaluation of the HIFU ablation effect on tumor-bearing mice model The murine breast cancer 4T1 cells (5×106 cell mL-1, dispersed into 0.2 mL DMEM medium) were subcutaneously injected into Balb/c mice. The in vivo evaluation of HIFU


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ablation effect was carried out when the major diameter of the tumor reach 1 cm. The three groups of mice separately received HIFU exposure at a certain power output of (100 W) for 10s after different administrations: (1) intravenous injection with saline solution; (2) intravenous injection with samples (PEA@OSNCs-iv); (3) intratumor injection with samples (PEA@OSNCs-ih). The mice were euthanized and anatomized immediately after receiving HIFU therapy. After that, the tumor of each mouse was collected and cut into two parts with similar volume. One part was stained with 1 w% triphenyltetrazolium chloride (TTC) solution for about 15 min until the boundary of necrosis region was clearly observed. Then, the ablation volume was measured and calculated following the equation of V=π×L×W2/6. Meanwhile, the other part of tumor was utilized for the pathological examination. Briefly, the tissue containing the boundary of a thermal ablation zone was isolated and fixed in 10% formalin. The H&E analysis of the obtained samples was carried out by Wuhan Google biotechnology Co., Ltd.. Cell apoptosis of tumor tissue was determined by TUNEL examination using a commercially available kit (Roche, Germany).


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ASSOCIATED CONTENT Supporting Information. Fig S1 shows the TEM images of PEA@OSNCs at low magnification. Fig S2 shows the pore size distribution of PEA@OSNCs. Fig S3 provides the FTIR transmission spectrum of the PEA@OSNCs. Fig S4 shows the hydrodynamic size distributions of PEA@OSNCs in deionized water and the UV-vis absorption strengths of PEA@OSNCs dispersion at different time intervals. Fig S5 provides the biodistribution of Si element in tumor-bearing nude mice at 30 min after intravenous injection of PEA@OSNCs. Fig S6 provides the TEM images of nanostructure prepared without using PEA. Fig S7 shows TEM images of the obtained PEA@OSNCs with different adding amount of Fe3O4 NPs. Fig S8 shows the cytotoxicity results of PEA@OSNCs against 4T1 and HL-7702 cells by WST-8 assay. Fig S9 shows the cytotoxicity results of PEA@OSNCs by trypan blue exclusion test. Fig S10 provides XRD pattern of PEA@OSNCs. Fig S11 shows the amplification figure of field-dependent magnetization curve in the low-field region. Fig S12 shows the FC and ZFC magnetization curves of PEA@OSNCs were measured at 5–350 K by SQUID. Fig S13 shows the In vivo T2-weighted MR images of a xenografted tumor model before and after intravenous injection of PEA@OSNCs suspension. Fig S14 shows the quantitative result of PEA content in PEA@OSNCs. Fig S15 provides the PEA release curve in the absence and presence of HIFU. Fig S16 provides the microscopy images of representative tissue section stained with H&E. Fig S17 provides the representative images of TUNEL-stained tumor tissues in control and PEA@OSNCs-iv group.

AUTHOR INFORMATION Corresponding Author


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Hangrong Chen State Key Lab of High Performance Ceramic and Superfine Microstructures, Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050, P. R. China E-mail: [email protected]

Hairong Zheng Paul C. Lauterbur Research Center for Biomedical Imaging, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen 518055, P. R. China E-mail: [email protected] Author Contributions ‡

These authors contributed equally. M. Ma and F. Yan conceived and designed the

experiments. M. Ma, M. Yao, Z. Wei, D. Zhou and H. Yao performed the experiments. M. Ma and H. Chen analyzed the data. M. Ma, H. Chen, J. Shi and H. Zheng co-wrote the paper. All authors discussed the results and commented on the manuscript. ACKNOWLEDGMENT We thank Prof. Faqi Li, Mr. Qi Wang and Ms. Wenting Chen for their help in ex vivo HIFU ablation and MRI characterizations. This work was supported by China National Funds for Distinguished Young Scientists (Grant No.51225202), National Natural Science Foundation of China (Grant No.51402329, 81371563, 81601499), Science Foundation for Youth Scholar


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of State Key Laboratory of High Performance Ceramics and Superfine Microstructures (Grant No.SKL201404) and Shanghai Excellent Academic Leaders Program (Grant No.14XD1403800). ABBREVIATIONS HMSN, hollow mesoporous silica nanoparticle; PEA, isopentyl acetate; KPS, potassium persulfate; HIFU, high intensity focused ultrasound; NP, nanoparticle; MRI, magnetic resonance imaging; CA, contrast agent; PCL, phase-change liquid; TPM, 3-(trimethoxysilyl) propyl methacrylate; H&E, hematoxylin-eosin; VSM, vibrating sample magnetometer; SQUID, superconducting quantum interference device; MS, magnetization saturation; PFOB, perfluorooctyl bromide; GC-MS, gas chromatography–mass spectrometry

REFERENCES 1. Zheng, D. W.; Li, B.; Li, C. X.; Fan, J. X.; Lei, Q.; Li, C.; Xu, Z.; Zhang, X. Z., Carbon-Dot-Decorated Carbon Nitride Nanoparticles for Enhanced Photodynamic Therapy against Hypoxic Tumor via Water Splitting. Acs Nano 2016, DOI: 10.1021/acsnano.6b04156. 2. Zheng, D. W.; Chen, J. L.; Zhu, J. Y.; Rong, L.; Li, B.; Lei, Q.; Fan, J. X.; Zou, M. Z.; Li, C.; Cheng, S. X.; Xu, Z.; Zhang, X. Z., Highly Integrated Nano-Platform for Breaking the Barrier between Chemotherapy and Immunotherapy. Nano. Lett. 2016, 16, 4341-4347. 3. Meng, H. A.; Liong, M.; Xia, T. A.; Li, Z. X.; Ji, Z. X.; Zink, J. I.; Nel, A. E., Engineered Design of Mesoporous Silica Nanoparticles to Deliver Doxorubicin and P-Glycoprotein siRNA to Overcome Drug Resistance in a Cancer Cell Line. Acs Nano 2010, 4, 4539-4550. 4. Singh, D.; McMillan, J. M.; Liu, X. M.; Vishwasrao, H. M.; Kabanov, A. V.; Sokolsky-Papkov, M.; Gendelman, H. E., Formulation Design Facilitates Magnetic Nanoparticle Delivery to Diseased Cells and Tissues. Nanomedicine (London, U. K.) 2014, 9, 469-485. 5. Kievit, F. M.; Zhang, M. Q., Cancer Nanotheranostics: Improving Imaging and Therapy by Targeted Delivery Across Biological Barriers. Adv. Mater. 2011, 23, 217-247. 6. Lim, E. K.; Kim, T.; Paik, S.; Haam, S.; Huh, Y. M.; Lee, K., Nanomaterials for Theranostics: Recent Advances and Future Challenges. Chem. Rev. 2015, 115, 327-394.


30

Page 31 of 34

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


7. Lee, B.-Y.; Li, Z.; Clemens, D. L.; Dillon, B. J.; Hwang, A. A.; Zink, J. I.; Horwitz, M. A., Redox-Triggered Release of Moxifloxacin from Mesoporous Silica Nanoparticles Functionalized with Disulfide Snap-Tops Enhances Efficacy Against Pneumonic Tularemia in Mice. Small 2016, 12, 3690-3702. 8. Li, T. T.; Shen, X.; Geng, Y.; Chen, Z. Y.; Li, L.; Li, S.; Yang, H.; Wu, C. H.; Zeng, H. J.; Liu, Y. Y., Folate-Functionalized Magnetic-Mesoporous Silica Nanoparticles for Drug/Gene Codelivery to Potentiate the Antitumor Efficacy. ACS Appl. Mater. Interfaces 2016, 8, 13748-13758. 9. Liu, B.; Li, C. X.; Ma, P. A.; Chen, Y. Y.; Zhang, Y. X.; Hou, Z. Y.; Huang, S. S.; Lin, J., Multifunctional NaYF4:Yb, Er@mSiO2@Fe3O4-PEG Nanoparticles for UCL/MR Bioimaging and Magnetically Targeted Drug Delivery. Nanoscale 2015, 7, 1839-1848. 10. Chen, D. Q.; Dougherty, C. A.; Zhu, K. C.; Hong, H., Theranostic Applications of Carbon Nanomaterials in Cancer: Focus on Imaging and Cargo Delivery. J. Controlled Release 2015, 210, 230-245. 11. Wang, D.; Lin, B. B.; Ai, H., Theranostic Nanoparticles for Cancer and Cardiovascular Applications. Pharm. Res. 2014, 31, 1390-1406. 12. Sumer, B.; Gao, J. M., Theranostic Nanomedicine for Cancer. Nanomedicine (London, U. K.) 2008, 3, 137-140. 13. Tarn, D.; Ashley, C. E.; Xue, M.; Carnes, E. C.; Zink, J. I.; Brinker, C. J., Mesoporous Silica Nanoparticle Nanocarriers: Biofunctionality and Biocompatibility. Acc. Chem. Res. 2013, 46, 792-801. 14. Xiao, D.; Jia, H. Z.; Zhang, J.; Liu, C. W.; Zhuo, R. X.; Zhang, X. Z., A Dual-Responsive Mesoporous Silica Nanoparticle for Tumor-Triggered Targeting Drug Delivery. Small 2014, 10, 591-598. 15. Meng, H.; Wang, M. Y.; Liu, H. Y.; Liu, X. S.; Situ, A.; Wu, B.; Ji, Z. X.; Chang, C. H.; Nel, A. E., Use of a Lipid-Coated Mesoporous Silica Nanoparticle Platform for Synergistic Gemcitabine and Paclitaxel Delivery to Human Pancreatic Cancer in Mice. Acs Nano 2015, 9, 3540-3557. 16. Geng, J.; Li, M.; Wu, L.; Chen, C. E.; Qu, X. G., Mesoporous Silica Nanoparticle-based H2O2 Responsive Controlled-Release System Used for Alzheimer's Disease Treatment. Adv. Healthcare Mater. 2012, 1, 332-336. 17. Lee, J. E.; Lee, N.; Kim, T.; Kim, J.; Hyeon, T., Multifunctional Mesoporous Silica Nanocomposite Nanoparticles for Theranostic Applications. Acc. Chem. Res. 2011, 44, 893-902. 18. Fowler, C. E.; Khushalani, D.; Mann, S., Interfacial Synthesis of Hollow Microspheres of Mesostructured Silica. Chem. Commun. 2001, 19，2028-2029. 19. Lai, N. C.; Lin, C. H.; Ku, P. H.; Chang, L. L.; Liao, K. W.; Lin, W. T.; Yang, C. M., Hollow Mesoporous Ia3d Silica Nanospheres with Singleunit-Cell-Thick Shell: Spontaneous Formation and Drug Delivery Application. Nano Res. 2014, 7, 1439-1448. 20. Chen, D.; Li, L. L.; Tang, F. Q.; Qi, S. O., Facile and Scalable Synthesis of Tailored Silica "Nanorattle" Structures. Adv. Mater. 2009, 21, 3804-3807. 21. Zhang, H. J.; Xu, H. J.; Wu, M. H.; Zhong, Y. F.; Wang, D. H.; Jiao, Z., A Soft-Hard Template Approach Towards Hollow Mesoporous Silica Nanoparticles with Rough Surfaces for Controlled Drug Delivery and Protein Adsorption. J. Mater. Chem. B 2015, 3, 6480-6489.


31


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

Page 32 of 34

22. Yin, Y. Y.; Chen, M.; Zhou, S. X.; Wu, L. M., A General and Feasible Method for the Fabrication of Functional Nanoparticles in Mesoporous Silica Hollow Composite Spheres. J. Mater. Chem. 2012, 22, 11245-11251. 23. Chen, J. C.; Xue, Z. T.; Feng, S. S.; Tu, B.; Zhao, D. Y., Synthesis of Mesoporous Silica Hollow Nanospheres with Multiple Gold Cores and Catalytic Activity. J. Colloid Interface Sci. 2014, 429, 62-67. 24. Zhu, Y. F.; Ikoma, T.; Hanagata, N.; Kaskel, S., Rattle-Type Fe3O4@SiO2 Hollow Mesoporous Spheres as Carriers for Drug Delivery. Small 2010, 6, 471-478. 25. Kim, T.; Momin, E.; Choi, J.; Yuan, K.; Zaidi, H.; Kim, J.; Park, M.; Lee, N.; McMahon, M. T.; Quinones-Hinojosa, A.; Bulte, J. W. M.; Hyeon, T.; Gilad, A. A., Mesoporous Silica-Coated Hollow Manganese Oxide Nanoparticles as Positive T-1 Contrast Agents for Labeling and MRI Tracking of Adipose-Derived Mesenchyrnal Stem Cells. J. Am. Chem. Soc. 2011, 133, 2955-2961. 26. Zhang, Q.; Wang, W. S.; Goebl, J.; Yin, Y. D., Self-Templated Synthesis of Hollow Nanostructures. Nano Today 2009, 4, 494-507. 27. He, Q. J.; Zhang, Z. W.; Gao, Y.; Shi, J. L.; Li, Y. P., Intracellular Localization and Cytotoxicity of Spherical Mesoporous Silica Nano- and Microparticles. Small 2009, 5, 2722-2729. 28. Kalbacova, M.; Verdanova, M.; Mravec, F.; Halasova, T.; Pekar, M., Effect of CTAB and CTAB in the Presence of Hyaluronan on Selected Human Cell Types. Colloids Surf., A 2014, 460, 204-208. 29. Meng, H.; Xue, M.; Xia, T.; Ji, Z. X.; Tarn, D. Y.; Zink, J. I.; Nel, A. E., Use of Size and a Copolymer Design Feature to Improve the Biodistribution and the Enhanced Permeability and Retention Effect of Doxorubicin-Loaded Mesoporous Silica Nanoparticles in a Murine Xenograft Tumor Model. Acs Nano 2011, 5, 4131-4144. 30. Kennedy, J. E., High-Intensity Focused Ultrasound in the Treatment of Solid Tumours. Nat. Rev. Cancer 2005, 5, 321-327. 31. Tempany, C. M. C.; McDannold, N. J.; Hynynen, K.; Jolesz, F. A., Focused Ultrasound Surgery in Oncology: Overview and Principles. Radiology 2011, 259, 39-56. 32. Chen, Y.; Chen, H. R.; Sun, Y.; Zheng, Y. Y.; Zeng, D. P.; Li, F. Q.; Zhang, S. J.; Wang, X.; Zhang, K.; Ma, M.; He, Q. J.; Zhang, L. L.; Shi, J. L., Multifunctional Mesoporous Composite Nanocapsules for Highly Efficient MRI-Guided High-Intensity Focused Ultrasound Cancer Surgery. Angew. Chem., Int. Ed. 2011, 50, 12505-12509. 33. Takeda, A., Manganese Action in Brain Function. Brain Res. Rev. 2003, 41, 79-87. 34. Wang, X.; Chen, H. R.; Chen, Y.; Ma, M.; Zhang, K.; Li, F. Q.; Zheng, Y. Y.; Zeng, D. P.; Wang, Q.; Shi, J. L., Perfluorohexane-Encapsulated Mesoporous Silica Nanocapsules as Enhancement Agents for Highly Efficient High Intensity Focused Ultrasound (HIFU). Adv. Mater. 2012, 24, 785-791. 35. Sacanna, S.; Kegel, W. K.; Philipse, A. P., Spontaneous Oil-in-Water Emulsification Induced by Charge-Stabilized Dispersions of Various Inorganic Colloids. Langmuir 2007, 23, 10486-10492. 36. Ma, M.; Chen, H. R.; Chen, Y.; Zhang, K.; Wang, X.; Cui, X. Z.; Shi, J. L., Hyaluronic Acid-Conjugated Mesoporous Silica Nanoparticles: Excellent Colloidal Dispersity in Physiological Fluids and Targeting Efficacy. J. Mater. Chem. 2012, 22, 5615-5621.


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37. Kim, J.; Kim, H. S.; Lee, N.; Kim, T.; Kim, H.; Yu, T.; Song, I. C.; Moon, W. K.; Hyeon, T., Multifunctional Uniform Nanoparticles Composed of a Magnetite Nanocrystal Core and a Mesoporous Silica Shell for Magnetic Resonance and Fluorescence Imaging and for Drug Delivery. Angew. Chem., Int. Ed. 2008, 47, 8438-8441. 38. Ma, M.; Zheng, S. G.; Chen, H. R.; Yao, M. H.; Zhang, K.; Jia, X. Q.; Mou, J.; Xu, H. X.; Wu, R.; Shi, J. L., A Combined "RAFT" and "Graft From" Polymerization Strategy for Surface Modification of Mesoporous Silica Nanoparticles: Towards Enhanced Tumor Accumulation and Cancer Therapy Efficacy. J. Mater. Chem. B 2014, 2, 5828-5836. 39. Lu, J.; Liong, M.; Zink, J. I.; Tamanoi, F., Mesoporous Silica Nanoparticles as a Delivery System for Hydrophobic Anticancer Drugs. Small 2007, 3, 1341-1346. 40. Yang, H. T.; Ogawa, T.; Hasegawa, D.; Takahashi, M., Synthesis and Magnetic Properties of Monodisperse Magnetite Nanocubes. J. Appl. Phys. 2008, 103, DOI: 10.1063/1.2833820. 41. Wang, Y. J.; Peng, X. H.; Shi, J. M.; Tang, X. L.; Jiang, J.; Liu, W. S., Highly Selective Fluorescent Chemosensor for Zn2+ Derived from Inorganic-Organic Hybrid Magnetic Core/Shell Fe3O4@SiO2 Nanoparticles. Nanoscale Res. Lett. 2012, 7, 1-13. 42. Hoskins, C.; Min, Y.; Gueorguieva, M.; McDougall, C.; Volovick, A.; Prentice, P.; Wang, Z. G.; Melzer, A.; Cuschieri, A.; Wang, L. J., Hybrid Gold-Iron Oxide Nanoparticles as a Multifunctional Platform for Biomedical Application. J. Nanobiotechnol. 2012, 10: 27. 43. Tan, H.; Xue, J. M.; Shuter, B.; Li, X.; Wang, J., Synthesis of PEOlated Fe3O4@SiO2 Nanoparticles via Bioinspired Silification for Magnetic Resonance Imaging. Adv. Funct. Mater. 2010, 20, 722-731. 44. Ai, H.; Flask, C.; Weinberg, B.; Shuai, X.; Pagel, M. D.; Farrell, D.; Duerk, J.; Gao, J. M., Magnetite-Loaded Polymeric Micelles as Ultrasensitive Magnetic-Resonance Probes. Adv. Mater. 2005, 17, 1949-1952. 45. Yuan, Y.; Ding, Z.; Qian, J.; Zhang, J.; Xu, J.; Dong, X.; Han, T.; Ge, S.; Luo, Y.; Wang, Y.; Zhong, K.; Liang, G., Casp3/7-Instructed Intracellular Aggregation of Fe3O4 Nanoparticles Enhances T2 MR Imaging of Tumor Apoptosis. Nano Lett. 2016, 16, 2686-2691. 46. Dong, L. L.; Peng, H. L.; Wang, S. Q.; Zhang, Z.; Li, J. H.; Ai, F. R.; Zhao, Q.; Luo, M.; Xiong, H.; Chen, L. X., Thermally and Magnetically Dual- Responsive Mesoporous Silica Nanospheres: Preparation, Characterization, and Properties for the Controlled Release of Sophoridine. J. Appl. Polym. Sci. 2014, DOI: 10.1002/app.40477. 47. Pisani, E.; Tsapis, N.; Galaz, B.; Santin, M.; Berti, R.; Taulier, N.; Kurtisovski, E.; Lucidarme, O.; Ourevitch, M.; Doan, B. T.; Beloeil, J. C.; Gillet, B.; Urbach, W.; Bridal, S. L.; Fattal, E., Perfluorooctyl Bromide Polymeric Capsules as Dual Contrast Agents for Ultrasonography and Magnetic Resonance Imaging. Adv. Funct. Mater. 2008, 18, 2963-2971.


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