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(シンポジウム 東京女子医科大学・早稲田大学連携先端生命医科学研究教育施設について)(3)ナノメディシンに向けた医用材料の開発の現状と展望
No full text第74回東京女子医科大学学会総会 平成20年9月27日(土) 東京女子医科大学 弥生記念講
Preparation, Characterization, and Preliminary In Vitro Testing of Nanoceria-Loaded Liposomes
No full textCerium oxide nanoparticles (nanoceria), well known for their pro- and antioxidant features, have been recently proposed for the treatment of several pathologies, including cancer and neurodegenerative diseases. However, interaction between nanoceria and biological molecules such as proteins and lipids, short blood circulation time, and the need of a targeted delivery to desired sites are some aspects that require strong attention for further progresses in the clinical application of these nanoparticles. The aim of this work is the encapsulation of nanoceria into a liposomal formulation in order to improve their therapeutic potentialities. After the preparation through a reverse-phase evaporation method, size, Z-potential, morphology, and loading efficiency of nanoceria-loaded liposomes were investigated. Finally, preliminary in vitro studies were performed to test cell uptake efficiency and preserved antioxidant activity. Nanoceria-loaded liposomes showed a good colloidal stability, an excellent biocompatibility, and strong antioxidant properties due to the unaltered activity of the entrapped nanoceria. With these results, the possibility of exploiting liposomes as carriers for cerium oxide nanoparticles is demonstrated here for the first time, thus opening exciting new opportunities for in vivo applications
Sumac (Rhus coriaria) Extract-Loaded Polymeric Nanosheets Efficiently Protect Human Dermal Fibroblasts from Oxidative Stress
Get PDFUnder healthy physiological conditions, living organisms possess a variety of antioxidant mechanisms to scavenge overproduced reactive oxygen species (ROS). However, under pathological circumstances, endogenous antioxidant systems may not be adequate to eliminate the excessive amount of oxidants, and thus, a continuous exogenous antioxidant income is required. In this regard, sumac (Rhus coriaria) extract is a good candidate for therapeutic applications, because of its high content of antioxidant polyphenolic compounds. In this work, sumac extract-loaded nanosheets (sumac-nanosheet) have been exploited for loading and controlled release of sumac extract, envisioning topical drug delivery applications. Sumac extract has been obtained through the solvent extraction method, and polymeric nanosheets have been thereafter prepared through the spin coating-assisted layer-by-layer deposition of polycaprolactone (PCL), sumac extract, and poly(d,l-lactic acid) (PDLLA). The collected data show a rich content of the sumac extract in terms of polyphenolic compounds, as well as its strong antioxidant properties. Moreover, for the first time in the literature, we demonstrated the possibility of efficiently loading such extract in polymeric nanosheets and the suitability of this nanoplatform as a reactive oxygen species scavenger in human dermal fibroblasts treated with a pro-oxidant insult
Magnetic driven alginate nanoparticles for targeted drug delivery
No full textThe aim of this paper is to develop highly magnetized, biodegradable and biocompatible, polymeric nanoparticles for drug delivery intell therapy. Alginate magnetic nanoparticles are realized by an emulsion/reticulation technique, after the dispersion of magnetite in an alginate solution. Such nanoparticles are characterized in terms of external morphology (FIB imaging), microstructure (TEM imaging), size distribution, zeta potential, magnetic properties (SQUID analysis) and drug release behaviour. Magnetization curves hsow the typical trend of superparamagnetic materials. Important parameters, such as magnetic permeability and magnetic momentum, are derived by employing Langevin theory. Experimental results reveal that a bi-exponential model fully describes the drug release. Finally, in vitro experiments on NIH/3T3 cells are carried out and demonstrate that our magnetic alginate nanoparticles can effectively drive the drug delivery towards an external magnetic field source
Biohybrid Actuators Based on Skeletal Muscle-Powered Microgrooved Ultrathin Films Consisting of Poly(styrene-block-butadiene-block-styrene)
No full textThis paper describes a biohybrid actuator consisting of a microgrooved thin film, powered by contractile, aligned skeletal muscle cells. The system was made of a thermoplastic elastomer [SBS, poly(styrene-block-butadiene-block-styrene)]. We prepared SBS thin films with different thicknesses (0.5–11.7 μm) and Young’s moduli (46.7–68.6 MPa) to vary their flexural rigidity. The microgrooves on the SBS thin film resembled the microstructure of the extracellular matrix of muscle and facilitated the alignment and differentiation of skeletal muscle cells. Electrical stimulation was applied to self-standing biohybrid thin films to trigger their contraction, enabled by the low flexural rigidity of the SBS thin film. Finite element model simulations were also examined to predict their contractile behavior. We achieved the prediction of displacements, which were rather close to the actual values of the SBS thin film: the discrepancy was <5% on the X axis. These results pave the way for in silico prediction of the contractile capabilities of elastomeric thin films. This study highlights the potential of microgrooved SBS thin films as ultraflexible platforms for biohybrid machines
A few immobilized thrombins are sufficient for platelet spreading.
Get PDFAbstractEukaryotic cells respond to signaling molecules with picomolar to nanomolar sensitivities. However, molar concentrations give no suggestion of the sufficient number of molecules per cell and are confusing when referring to physiological situations in which signaling molecules act in an immobilized state. Here, we studied platelet adhesion by thrombin, a key step in normal hemostasis and pathological arterial thrombosis. We generated a biofunctional nanosheet surface to mimic the in vivo solid-state interaction between platelets and thrombin at sites of injured tissues. We observed that <10 molecules readily activate platelets with high specificity, resulting in platelet adhesion and spreading. This number is much lower than expected from previous experiments in solution, in which the sole activation of platelets required a >1000-fold stoichiometric excess of thrombin. We conclude that immobilizing thrombin apposed to the membrane receptor allows platelets to respond with very high sensitivity. Moreover, we propose that irreversible cell activation may require several ligands to avoid activation by single, mislocalized signaling molecules
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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