The primary advantage of the Geostationary Ocean Color Imager (GOCI), the world's first geostationary ocean color observation satellite, over other ocean color satellite imagers is that it can obtain ...data every hour during the daytime, allowing ocean monitoring in near real time. Here, we investigated temporal variation in turbidity along a coastal region. To estimate suspended sediment concentrations (SSC), water samples and radiometric data were collected from waters in the Mokpo coastal area, located along the west coast of Korea. GOCI images acquired on the same day as the samples were used to generate a map of turbidity and to estimate the differences in SSC displayed in each image. Hourly GOCI images successfully identified the temporal variation in turbidity, which is mainly driven by the tidal cycle. A hydrodynamic model also showed that the GOCI‐derived turbidity variation was reliable. This study shows that the GOCI can be effectively used to monitor the temporal dynamics of the turbidity of coastal waters, i.e., sediment movements driven by the tidal cycle along the west coast of the Korean Peninsula.
Key Points
GOCI, the world's first geostationary ocean color observation satellite
Investigate hourly variation in the image‐derived turbidity of coastal waters
Monitor turbidity changes in coastal waters based on the tidal cycle
Renal clearance of quantum dots Bawendi, Moungi G; Frangioni, John V; Soo Choi, Hak ...
Nature biotechnology,
10/2007, Letnik:
25, Številka:
10
Journal Article
Recenzirano
Odprti dostop
The field of nanotechnology holds great promise for the diagnosis and treatment of human disease. However, the size and charge of most nanoparticles preclude their efficient clearance from the body ...as intact nanoparticles. Without such clearance or their biodegradation into biologically benign components, toxicity is potentially amplified and radiological imaging is hindered. Using intravenously administered quantum dots in rodents as a model system, we have precisely defined the requirements for renal filtration and urinary excretion of inorganic, metal-containing nanoparticles. Zwitterionic or neutral organic coatings prevented adsorption of serum proteins, which otherwise increased hydrodynamic diameter by >15 nm and prevented renal excretion. A final hydrodynamic diameter <5.5 nm resulted in rapid and efficient urinary excretion and elimination of quantum dots from the body. This study provides a foundation for the design and development of biologically targeted nanoparticles for biomedical applications.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We have developed a versatile nanoparticle construct using a compact cysteine coating on a CdSe(ZnCdS) core(shell) nanocrystal (QD-Cys) that is biologically compatible, exceptionally compact, highly ...fluorescent, and easily functionalized. The small hydrodynamic diameter of QD-Cys (∼6 nm) allows for renal clearance of these nanoparticles in rat models. Moreover, the ability to directly conjugate to QD-Cys opens up the possibility of functionalized nanocrystals for in vivo targeted imaging, in which small targeting molecules can be appended to QD-Cys, and unbound QDs can be rapidly cleared to achieve high signal/noise ratios and to reduce background toxicity.
Passive targeting of large nanoparticles by the enhanced permeability and retention (EPR) effect is a crucial concept for solid tumor targeting in cancer nanomedicine. There is, however, a trade‐off ...between the long‐term blood circulation of nanoparticles and their nonspecific background tissue uptake. To define this size‐dependent EPR effect, near‐infrared fluorophore‐conjugated polyethylene glycols (PEG‐ZW800s; 1–60 kDa) are designed and their biodistribution, pharmacokinetics, and renal clearance are evaluated in tumor‐bearing mice. The targeting efficiency of size‐variant PEG‐ZW800s is investigated in terms of tumor‐to‐background ratio (TBR). Interestingly, smaller sized PEGs (≤20 kDa, 12 nm) exhibit significant tumor targeting with minimum to no nonspecific uptakes, while larger sized PEGs (>20 kDa, 13 nm) accumulate highly in major organs, including the lungs, liver, and pancreas. Among those tested, 20 kDa PEG‐ZW800 exhibits the highest TBR, while excreting unbound molecules to the urinary bladder. This result lays a foundation for engineering tumor‐targeted nanoparticles and therapeutics based on the size‐dependent EPR effect.
Enhanced permeability and retention based passive tumor targeting of polymeric nanoparticles should consider the effect of molecular weight and hydrodynamic diameter on their biodistribution, pharmacokinetics, and renal clearance.
Because of their large size compared to small molecules and their multifunctionality, nanoparticles (NPs) hold promise as biomedical imaging, diagnostic, and theragnostic agents. However, the key to ...their success hinges on a detailed understanding of their behavior after administration into the body. NP biodistribution, target binding, and clearance are complex functions of their physicochemical properties in serum, which include hydrodynamic diameter, solubility, stability, shape and flexibility, surface charge, composition, and formulation. Moreover, many materials used to construct NPs have real or potential toxicity or may interfere with other medical tests. In this review, we discuss the design considerations that mediate NP behavior in the body and the fundamental principles that govern clinical translation. By analyzing those nanomaterials that have already received regulatory approval, most of which are actually therapeutic agents, we attempt to predict which types of NPs hold potential as diagnostic agents for biomedical imaging. Finally, using quantum dots as an example, we provide a framework for deciding whether an NP-based agent is the best choice for a particular clinical application.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The field of biomedical optics has matured rapidly over the last decade and is poised to make a significant impact on patient care. In particular, wide-field (typically > 5 cm), planar, near-infrared ...(NIR) fluorescence imaging has the potential to revolutionize human surgery by providing real-time image guidance to surgeons for tissue that needs to be resected, such as tumors, and tissue that needs to be avoided, such as blood vessels and nerves. However, to become a clinical reality, optimized imaging systems and NIR fluorescent contrast agents will be needed. In this review, we introduce the principles of NIR fluorescence imaging, analyze existing NIR fluorescence imaging systems, and discuss the key parameters that guide contrast agent development. We also introduce the complexities surrounding clinical translation using our experience with the Fluorescence-Assisted Resection and Exploration (FLARE™) imaging system as an example. Finally, we introduce state-of-the-art optical imaging techniques that might someday improve image-guided surgery even further.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
This is the first report, to our knowledge, of the preparation of an injectable in situ–forming click-crosslinked hyaluronic acid (Cx-HA) hydrogel (Cx-HA-CM) containing chemical immobilized ...cytomodulin-2 (CM), a chondrogenic differentiation factor, and on the utility of human periodontal ligament stem cells (hPLSCs) as a cell source for cartilage tissue engineering. hPLSCs served here as a stem cell source tolerant to ex vivo manipulation. CM induced in vitro chondrogenic differentiation of hPLSCs comparable to induction with traditional TGF-β. Cx-HA was prepared via a click-reaction between tetrazine-modified HA and transcyclooctene-modified HA. Cx-HA displayed significantly more features of a stiff hydrogel than HA. Cx-HA had a three-dimensional porous interconnected structure, absorbed a large volume of biological medium, and showed excellent biocompatibility. In contrast to HA, the Cx-HA hydrogel persisted in vitro and in vivo for an extended period, as evidenced by in vivo near-infrared fluorescence imaging. CM covalently linked to Cx-HA (Cx-HA-CM) remained inside Cx-HA for a prolonged period compared with CM physically loaded onto Cx-HA Cx-HA (+CM). Cx-HA-CM also caused better chondrogenic differentiation of hPLSCs, as evidenced by Alcian blue and Safranin O staining, and greater increases in the expression of type II collagen, glycosaminoglycan content and SOX9, aggrecan, and type 2α1 collagen mRNA levels. Thus, compared to Cx-HA (+CM), the hPLSC-loaded Cx-HA-CM hydrogel induced greater chondrogenic differentiation of hPLSCs via CM that was retained in the hydrogel for a much longer period of time.
When designing drug carriers, the drug-to-carrier ratio is an important consideration, because the use of high quantities of carriers can result in toxicity as a consequence of poor metabolism and ...elimination of the carriers. However, these issues would be of less concern if both the drug and carrier had therapeutic effects. (-)-Epigallocatechin-3-O-gallate (EGCG), a major ingredient of green tea, has been shown, for example, to possess anticancer effects, anti-HIV effects, neuroprotective effects and DNA-protective effects. Here, we show that sequential self-assembly of the EGCG derivative with anticancer proteins leads to the formation of stable micellar nanocomplexes, which have greater anticancer effects in vitro and in vivo than the free protein. The micellar nanocomplex is obtained by complexation of oligomerized EGCG with the anticancer protein Herceptin to form the core, followed by complexation of poly(ethylene glycol)-EGCG to form the shell. When injected into mice, the Herceptin-loaded micellar nanocomplex demonstrates better tumour selectivity and growth reduction, as well as longer blood half-life, than free Herceptin.
The signal-to-background ratio (SBR) is the key determinant of sensitivity, detectability and linearity in optical imaging. As signal strength is often constrained by fundamental limits, background ...reduction becomes an important approach for improving the SBR. We recently reported that a zwitterionic near-infrared (NIR) fluorophore, ZW800-1, exhibits low background. Here we show that this fluorophore provides a much-improved SBR when targeted to cancer cells or proteins by conjugation with a cyclic RGD peptide, fibrinogen or antibodies. ZW800-1 outperforms the commercially available NIR fluorophores IRDye800-CW and Cy5.5 in vitro for immunocytometry, histopathology and immunoblotting and in vivo for image-guided surgery. In tumor model systems, a tumor-to-background ratio of 17.2 is achieved at 4 h after injection of ZW800-1 conjugated to cRGD compared to ratios of 5.1 with IRDye800-CW and 2.7 with Cy5.5. Our results suggest that introducing zwitterionic properties into targeted fluorophores may be a general strategy for improving the SBR in diagnostic and therapeutic applications.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The emergence of photoluminescent carbon-based nanomaterials has shown exciting potential in the development of benign nanoprobes. However, the in vivo kinetic behaviors of these particles that are ...necessary for clinical translation are poorly understood to date. In this study, fluorescent carbon dots (C-dots) were synthesized and the effect of three injection routes on their fate in vivo was explored by using both near-infrared fluorescence and positron emission tomography imaging techniques. We found that C-dots are efficiently and rapidly excreted from the body after all three injection routes. The clearance rate of C-dots is ranked as intravenous > intramuscular > subcutaneous. The particles had relatively low retention in the reticuloendothelial system and showed high tumor-to-background contrast. Furthermore, different injection routes also resulted in different blood clearance patterns and tumor uptakes of C-dots. These results satisfy the need for clinical translation and should promote efforts to further investigate the possibility of using carbon-based nanoprobes in a clinical setting. More broadly, we provide a testing blueprint for in vivo behavior of nanoplatforms under various injection routes, an important step forward toward safety and efficacy analysis of nanoparticles.
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