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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