Theranostic agents present a promising clinical approach for cancer detection and treatment. We herein introduce a microbubble and liposome complex (MB-Lipo) developed for ultrasound (US) imaging and activation. The MB-Lipo particles have a hybrid structure consisting of a MB complexed with multiple Lipos. The MB components are used to generate high echo signals in US imaging, while the Lipos serve as a versatile carrier of therapeutic materials. MB-Lipo allows high contrast US imaging of tumor sites. More importantly, the application of high acoustic pressure bursts MBs, which releases therapeutic Lipos and further enhances their intracellular delivery through sonoporation effect. Both imaging and drug release could thus be achieved by a single US modality, enabling in situ treatment guided by real-time imaging. The MB-Lipo system was applied to specifically deliver anti-cancer drug and genes to tumor cells, which showed enhanced therapeutic effect. We also demonstrate the clinical potential of MB-Lipo by imaging and treating tumor in vivo.

ObjectiveTo synthesize mesoporous silica-core-shell magnetic nanoparticles (MNPs) encapsulated by liposomes (Lipo [MNP@m-SiO2]) in order to enhance their stability, allow them to be used in any buffer solution, and to produce trastuzumab-conjugated (Lipo[MNP@m-SiO2]-Her2Ab) nanoparticles to be utilized in vitro for the targeting of breast cancer.Materials and MethodsThe physiochemical characteristics of Lipo[MNP@m-SiO2] were assessed in terms of size, morphological features, and in vitro safety. The multimodal imaging properties of the organic dye incorporated into Lipo[MNP@m-SiO2] were assessed with both in vitro fluorescence and MR imaging. The specific targeting ability of trastuzumab (Her2/neu antibody, Herceptin®)-conjugated Lipo[MNP@m-SiO2] for Her2/neu-positive breast cancer cells was also evaluated with fluorescence and MR imaging.ResultsWe obtained uniformly-sized and evenly distributed Lipo[MNP@m-SiO2] that demonstrated biological stability, while not disrupting cell viability. Her2/neu-positive breast cancer cell targeting by trastuzumab-conjugated Lipo[MNP@m-SiO2] was observed by in vitro fluorescence and MR imaging.ConclusionTrastuzumab-conjugated Lipo[MNP@m-SiO2] is a potential treatment tool for targeted drug delivery in Her2/neu-positive breast cancer.

50 nm Magnetic nanocluster (MNC) was deliberately selected as an efficient probe for the magnetic relaxation switching (MRSw) assay. After surface modification of MNCs with poly(acrylic acid) to give PAA-MNCs, and employing streptavidin-biotin interactions for the MRSw assay model, a few tenths pM concentration of strepavidin could be determined.

Melanin is a natural pigment that is widely distributed in many parts of the human body, such as the skin and retinal pigment epithelium (RPE) in eyes. In contrast to skin melanin, which is being constantly synthesized by the epidermal melanocytes, melanin in the RPE does not regenerate. Melanin is known to function as a potential radical scavenger and photoprotective agent. However, the protective effects of melanin against oxidative stress decline with increasing age. This phenomenon has been correlated with the pathogenesis of age-related macular degeneration (AMD). To increase the potential antioxidant and photoprotective characteristics of melanin, we designed a therapeutic strategy for replenishment of melanin using PEGyl­ated synthetic melanin-like nanoparticles (MNPs) in the RPE for the treatment of AMD. We performed experiments using AMD-like cellular and mouse models and demonstrated that MNPs are biocompatible and selectively target reactive oxygen species (ROS) with powerful antioxidant properties. MNPs can traffic and accumulate in the RPE and are exclusively located in cytosol, but not the nucleus and mitochondria of the cells, for at least 3 months after a single-dose intra­vitreal injection. Our findings demonstrate that MNPs are able to substitute for natural melanin in the RPE and suggest the potential efficacy of MNPs as a natural radical scavenger against oxidative stress in ROS-related diseases, such as AMD.

Molecular imaging has emerged as a new discipline in gastrointestinal endoscopy. This technology encompasses modalities that can visualize disease-specific morphological or functional tissue changes based on the molecular signature of individual cells. Molecular imaging has several advantages including minimal damage to tissues, repetitive visualization, and utility for conducting quantitative analyses. Advancements in basic science coupled with endoscopy have made early detection of gastrointestinal cancer possible. Molecular imaging during gastrointestinal endoscopy requires the development of safe biomarkers and exogenous probes to detect molecular changes in cells with high specificity anda high signal-to-background ratio. Additionally, a high-resolution endoscope with an accurate wide-field viewing capability must be developed. Targeted endoscopic imaging is expected to improve early diagnosis and individual therapy of gastrointestinal cancer.

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242 wileyonlinelibrary.com www.particle-journal.com www.MaterialsViews.com COMMUNICATION therapeutic agents and deliver these agents to the desired location after specifi c targeting.MNPs can accelerate the spin-spin relaxation of adjacent water molecules, resulting in the faster decay of 1 H NMR signals. The size or chemical composition of MNPs is optimized to increase the transverse relaxivity ( r 2 ), because high r 2 values are desirable as they can improve the magnetic detection or imaging sensitivity in magnetic resonance-based applications. The r 2 value is proportional to the size ( d ) and saturated mag-2 ) of MNPs. [ 6 ] The silica shell with amorphous structure coating is expected to improve the safety of the metal oxide particles, but the shell decreases the r 2 value because it decreases the number of water molecules around the magnetic fi eld from the MNP core.In this study, to overcome safety problems and the decreasing r 2 , mesoporous silica ( m SiO 2 ) material was utilized to form a shell around the MNP. The shell possesses a suffi cient number of water molecules inside the pores near the core particles to minimize the decrease in magnetic relaxivity for magnetic applications. [ 7 ] In terms of therapeutics, the mesoporous shell structure can provide suffi cient space for the incorporation of therapeutic agents and the controlled release by adjusting the pH.Generally, the particle surface should be fabricated with hydrophilic moiety as is used for polyethylene glycols (PEGs). This is because an amorphous or mesoporous silica shellcoated MNP does not exhibit long-term solution stability under aqueous solutions, particularly in neutral buffer solutions. [ 8 ] A liposomal formulation with biocompatible phospholipid chemicals was introduced to the magnetic core-shell nanoparticle after encapsulation of the chemical drugs and the therapeutic genes ( Figure S1, Supporting Information, MagLipo). [ 9 ] Additionally, for cancer targeting, a cancer specifi c antibody was anchored onto the thiol reactive (maleimide chemical functional group) MagLipo particle surface based on simple bio-conjugation chemistry (see the Experimental Section). [ 10 ] Briefl y, a 16 nm (diameter) iron oxide nanoparticle with a regular size distribution was synthesized using the seedgrowing method. [ 11 ] The MNP was characterized as having a typical ferrite spinel structure, and powder X-ray diffraction and vibrating sample magnetometry revealed that the MNP had a high M s (95 emu per g [Fe]) with superparamagnetism ( Figure 1 A and Figure S2, Supporting Information). To determine the magnetic relaxivity of MNP, the particle was dispersed in H 2 O after being treated with hexadecyltrimethylammonium bromide (CTAB) chemicals and the bare 16 nm MNP was found to have r 2 = 286 m M −1 S −1 by time domain-nuclear magnetic resonance (NMR, Minispec mq20, 0.47 T, Bruker, Billerica, MA, Nanoparticles with multifunctional abilities have been studied for diagnostic or therapeutic applications. [ 1 ] The technology, particularly imaging-gu...

Simple and versatile methodologies have been reported that customize the surface of superparamagnetic iron oxide (SPIO) nanoparticles and impart additional fluorescence capabilities to these contrast agents. Herein, we present the rational design, synthesis, characterization, and biological applications of a new magnetic-based fluorescent probe. The dual modality imaging protocol was developed by labeling fluorophore with alginate natural polymers that have excellent biocompatibility and biodegradability, and using gelification method to form nanocomposites containing SPIO. The formation of alginate-based fluorescent magnetic (AFM) nanoparticles was observed in spherical and elliptical forms with a diameter of less than 500 nm by a transmission electron microscope (TEM). The fluorescent wavelength band in the range of 560 nm was also confirmed in the UV-visible spectrophotometer. In this study, we demonstrate that the multi-tasking design of AFM nanoparticles provides an ideal platform for building balanced dual-image probes of magnetic resonance imaging and optical imaging.