3 research outputs found
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Injectable Thermosensitive Nanocomposites Based on Poly(N-vinylcaprolactam) and Silica Particles for Localized Release of Hydrophilic and Hydrophobic Drugs.
The systemic delivery of drugs employed by conventional methods has shown to be less effective than a localized delivery system. Many drugs have the effectiveness reduced by fast clearance, increasing the amount required for an efficient treatment. One way to overcome this drawback is through the use of thermoresponsive polymers that undergo a sol-gel transition at physiological temperature, allowing their injection directly in the desired site. In this work, thermosensitive nanocomposites based on poly(N-vinylcaprolactam) and silica particles with 80 and 330 nm were synthesized to be employed as delivery systems for hydrophobic (naringin) and hydrophilic (doxorubicin hydrochloride) drugs. The insertion of SiO2 increased the rheological properties of the nanocomposite at 37 °C, which helps to prevent its diffusion away from the site of injection. The synthesized materials were also able to control the drug release for a period of 7 days under physiological conditions. Due to its higher hydrophobicity and better interaction with the PNVCL matrix, naringin presented a more controlled release. The Korsmeyer-Peppas model indicated different release mechanisms for each drug. At last, a preliminary in vitro study of DOX-loaded nanocomposites cultured with L929 and MB49 cells showed negligible toxic effects on healthy cells and better efficient inhibition of carcinoma cells
Surface-dependent photocatalytic and biological activities of Ag2CrO4: Integration of experiment and simulation
In this work, we present a joint experimental and theoretical study towards unveiling the photocatalytic (photodegradation of Rhodamine B), the antifungal (towards Candida glabrata) and cytotoxicity (against the L929 cell line) of Ag2CrO4. X-ray diffraction, Rietveld refinements, micro-Raman, UV–Visible spectroscopies, and photoluminescence emissions have been employed to characterize the as-synthetized samples by a co-precipitation method in water and ammonia. To complement and rationalize the experimental results, first-principles calculations have been performed within the framework of density functional theory. The crystal morphologies were characterized by field emission scanning electron microscopy images, while the Wulff construction, obtained by the calculated values of the surface energy, was employed to model and match the experimental images by tuning the relative stability of the exposed surfaces. This experimental and theoretical study provides a detailed understanding of the transformations of morphology and can aid in the development of the surface-dependent photocatalytic and biological activities of Ag2CrO4. We believe that our results offer new insights regarding the local coordination of superficial Ag and Cr cations on each exposed surface of the corresponding morphology, provided some general principles for material design, that dictate the properties of Ag2CrO4, a field that has so far remained unexplored