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Background: The introduction of magnetic resonance (MR)-guided radiation treatment planning has opened a new space for theranostic nanoparticles to reduce acute toxicity while improving local control. In this work, second-generation AGuIX ® nanoparticles (AGuIX-Bi) are synthesized and validated. AGuIX-Bi are shown to maintain MR positive contrast while further amplifying the radiation dose by the replacement of some Gd 3+ cations with higher Z Bi 3+ . These next-generation nanoparticles are based on the AGuIX ® platform, which is currently being evaluated in multiple Phase II clinical trials in combination with radiotherapy. Methods: In this clinically scalable methodology, AGuIX ® is used as an initial chelation platform to exchange Gd 3+ for Bi 3+ . AGuIX-Bi nanoparticles are synthesized with three ratios of Gd/Bi, each maintaining MR contrast while further amplifying radiation dose relative to Bi 3+ . Safety, efficacy, and theranostic potential of the nanoparticles were evaluated in vitro and in vivo in a human non-small cell lung cancer model. Results: We demonstrated that increasing Bi 3+ in the nanoparticles is associated with more DNA damage and improves in vivo efficacy with a statistically significant delay in tumor growth and 33% complete regression for the largest Bi/Gd ratio tested. The addition of Bi 3+ by our synthetic method leads to nanoparticles that present slightly altered pharmacokinetics and lengthening of the period of high tumor accumulation with no observed evidence of toxicity. Conclusions: We confirmed the safety and enhanced efficacy of AGuIX-Bi with radiation therapy at the selected ratio of 30Gd/70Bi. These results provide crucial evidence towards patient translation., Competing Interests: Competing Interests: François Lux and Olivier Tillement have to disclose the patent WO2011/135101. François Lux, Olivier Tillement, and Ross Berbeco have to disclose the patent US62431607. Paul Rocchi, Léna Carmès Tristan Doussineau, and Sandrine Dufort are employees of NH TherAguix which develops AGuIX® nanoparticles. François Lux, Olivier Tillement, Tristan Doussineau, and Sandrine Dufort possess shares in the company, NH TherAguix., (© The author(s).)

Ultrasound (US) is one of the most commonly used clinical imaging techniques. However, the use of US and US-based intravenous agents extends far beyond imaging. In particular, there has been a surge in the fabrication of multimodality US contrast agents and theranostic US agents for cancer imaging and therapy. The unique interaction of US waves with microscale and nanoscale agents has attracted much attention in the development of contrast agents and drug-delivery vehicles. The dimensions of the agent not only dictate how it behaves in vivo, but also how it interacts with US for imaging and drug delivery. Furthermore, these agents are also unique due to their ability to convert from the nanoscale to the microscale and vice versa, having imaging and therapeutic utility in both dimensions. Here, we review multimodality and multifunctional US-based agents, according to their size, and also highlight recent developments in size conversion US agents. WIREs Nanomed Nanobiotechnol 2016, 8:796-813. doi: 10.1002/wnan.1398 For further resources related to this article, please visit the WIREs website., (© 2016 Wiley Periodicals, Inc.)

J-aggregates display nanoscale optical properties which enable their use in fluorescence and photoacoustic imaging applications. However, control over their optical properties in an in vivo setting is hampered by the conformational lability of the J-aggregate structure in complex biological environments. J-aggregating nanoparticles (JNP) formed by self-assembly of bacteriopheophorbide-lipid (Bchl-lipid) in lipid nanovesicles represents a novel strategy to stabilize J-aggregates for in vivo bioimaging applications. We find that 15 mol% Bchl-lipid embedded within a saturated phospholipid bilayer vesicle was optimal in terms of maximizing Bchl-lipid dye loading, while maintaining a spherical nanoparticle morphology and retaining spectral properties characteristic of J-aggregates. The addition of cholesterol maintains the stability of the J-aggregate absorption band for up to 6 hours in the presence of 90% FBS. In a proof-of-concept experiment, we successfully applied JNPs as a fluorescence contrast agent for real-time intraoperative detection of metastatic lymph nodes in a rabbit head-and-neck cancer model. Lymph node metastasis delineation was further verified by visualizing the JNP within the excised lymph node using photoacoustic imaging. Using JNPs, we demonstrate the possibility of using J-aggregates as fluorescence and photoacoustic contrast agents and may potentially spur the development of other nanomaterials that can stably induce J-aggregation for in vivo cancer bioimaging applications.

A novel class of all-organic nanoscale porphyrin nanodroplet agents is presented which is suitable for multimodality ultrasound and photoacoustic molecular imaging. Previous multimodality photoacoustic-ultrasound agents are either not organic, or not yet demonstrated to exhibit enhanced accumulation in leaky tumor vasculature, perhaps because of large diameters. In the current study, porphyrin nanodroplets are created with a mean diameter of 185 nm which is small enough to exhibit the enhanced permeability and retention effect. Porphyrin within the nanodroplet shell has strong optical absorption at 705 nm with an estimated molar extinction coefficient >5 × 10(9) m(-1) cm(-1) , allowing both ultrasound and photoacoustic contrast in the same nanoparticle using all organic materials. The potential of nanodroplets is that they may be phase-changed into microbubbles using high pressure ultrasound, providing ultrasound contrast with single-bubble sensitivity. Multispectral photoacoustic imaging allows visualization of nanodroplets when injected intratumorally in an HT1080 tumor in the chorioallantoic membrane of a chicken embryo. Intravital microscopy imaging of Hep3-GFP and HT1080-GFP tumors in chicken embryos determines that nanodroplets accumulated throughout or at the periphery of tumors, suggesting that porphyrin nanodroplets may be useful for enhancing the visualization of tumors with ultrasound and/or photoacoustic imaging., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Head and neck cancer is the fifth most common type of cancer worldwide and remains challenging for effective treatment due to the proximity to critical anatomical structures in the head and neck region, which increases the probability of toxicity from surgery and radiotherapy, and therefore emphasizes the importance of maximizing the targeted ablation. We have assessed the effectiveness of porphysome nanoparticles to enhance fluorescence and photoacoustic imaging of head and neck tumors in rabbit and hamster models. In addition, we evaluated the effectiveness of this agent for localized photothermal ablative therapy of head and neck tumors. We have demonstrated that porphysomes not only enabled fluorescence and photoacoustic imaging of buccal and tongue carcinomas, but also allowed for complete targeted ablation of these tumors. The supremacy of porphysome-enabled photothermal therapy over surgery to completely eradicate primary tumors and metastatic regional lymph node while sparing the adjacent critical structures' function has been demonstrated for the first time. This study represents a novel breakthrough that has the potential to revolutionize our approach to tumor diagnosis and treatment in head and neck cancer and beyond.

Converting nanoparticles or monomeric compounds into larger supramolecular structures by endogenous or external stimuli is increasingly popular because these materials are useful for imaging and treating diseases. However, conversion of microstructures to nanostructures is less common. Here, we show the conversion of microbubbles to nanoparticles using low-frequency ultrasound. The microbubble consists of a bacteriochlorophyll-lipid shell around a perfluoropropane gas. The encapsulated gas provides ultrasound imaging contrast and the porphyrins in the shell confer photoacoustic and fluorescent properties. On exposure to ultrasound, the microbubbles burst and form smaller nanoparticles that possess the same optical properties as the original microbubble. We show that this conversion is possible in tumour-bearing mice and could be validated using photoacoustic imaging. With this conversion, our microbubble can potentially be used to bypass the enhanced permeability and retention effect when delivering drugs to tumours.

Multifunctional nanoparticles have been developed to overcome the conventional hurdles associated with the diagnosis and treatment of disease. However, there are often caveats involved with the development and clinical translation of multifunctional nanoparticles largely regarding the notion that additional functionality increases nanoparticle complexity. Here, we discuss two design concepts, a conventional approach, 'all-in-one', and introduce the concept of 'one-for-all' to suggest that multifunctionality does not necessarily result in multicomponent complex nanoparticles. This review focuses on the design concepts of all-in-one and one-for-all with examples of each approach and a discussion on the implications for clinical translation., (Copyright © 2013 Wiley Periodicals, Inc.)

Highlights: [•] Porphysome nanovesicles are generated by porphyrin-lipid bilayers. [•] Porphyrin-lipid imparts unprecedented photonic properties to lipid nanoparticles. [•] Metal chelation of porphyrin-lipid unlocks porphysomes’ potential for PET and MRI. [•] The simple yet intrinsic multimodal nature of porphysomes facilitates their clinical translation. [•] Porphyrin-lipid supramolecular assembly expands beyond porphysome nanotechnology. [Copyright &y& Elsevier]

The article focuses on the author's experience of working in Professor Gang Zheng's laboratory at University of Toronto in Toronto, Ontario, where nanotechnology was used to image and combat diseases. It states that in the laboratory porphyrin-based nanoparticles were used, which had additional optical properties for photoacoustic and fluorescence imaging. It highlights the involvement of microtechnology in the field of nanotechnology.