Sushilkumar A. Jadhav

Thermoresponsive mesoporous silica nanoparticles as a carrier for skin delivery of quercetin.

Recently, mesoporous silica nanoparticles (MSNs) have emerged as promising drug delivery systems able to preserve the integrity of the carried substance and/or to selectively reach a target site; however, they have rarely been explored for skin application. In this study, thermoresponsive MSNs, designed to work at physiologic cutaneous temperature, are proposed as innovative topical carriers for quercetin (Q), a well-known antioxidant. The thermosensitive nanoparticles were prepared by functionalizing two different types of matrices, with pore size of 3.5nm (MSNsmall) and 5.0nm (MSNbig), carrying out a free radical copolymerization of N-isopropylacrylamide (NIPAM) and 3-(methacryloxypropyl)trimethoxysilane (MPS) inside the mesopores. The obtained copolymer-grafted MSNs (copoly-MSNs) were physico-chemically characterized and their biocompatibility was attested on a human keratinocyte cell line (HaCaT). The release profiles were assessed and the functional activity of Q, free or loaded, was evaluated in terms of antiradical and metal chelating activities. Ex vivo accumulation and permeation through porcine skin were also investigated. The characterization confirmed the copolymer functionalization of the MSNs. In addition, both the bare and functionalized silica matrices were found to be biocompatible. Among the copolymer-grafted complexes, Q/copoly-MSNbig exhibited more evident thermoresponsive behavior proving the potential of these thermosensitive systems for advanced dermal delivery.

Sensitivity of different resistant tumour cell lines to the two novel compounds (2Z,4E)-2-methylsulfanyl-5-(1-naphthyl)-4-nitro-2,4-pentadienoate and (1E,3E)-1,4-bis(2-naphthyl)-2,3-dinitro-1,3-butadiene

The inhibition of cell proliferation by methyl (2Z,4E)-2-methylsulfanyl-5-(1-naphthyl)-4-nitro-2,4-pentadienoate (1-Naph-NMCB) and (1E,3E)-1,4-bis(2-naphthyl)-2,3-dinitro-1,3-butadiene (2-Naph-DNB) has been studied in vitro against four cell lines selected for their resistance to doxorubicin, cisplatin, taxol and 5-fluorouracil. In previous experiments both compounds showed good in vitro antiproliferative, cytotoxic and pro-apoptotic activities against cell lines of different histologic origin. The results of the experiments presented here suggest that 1-Naph-NMCB is able to overcome all of the different mechanisms of resistance showed by the resistant cell lines used for our experiments. On the contrary, when we used the taxol-resistant A549-T12 cell line, characterized by a mechanism of resistance due to a mutation of the target site of taxol on microtubules, it displayed a partial but significant cross-resistance to 2-Naph-DNB. Although the actual mechanism of this cross-resistance has not yet been definitively elucidated, our results from immunostaining of microtubules suggest that it may be linked to the presence of a shared target site for taxol and 2-Naph-DNB on microtubules.

Incredible pace of research on mesoporous silica nanoparticles

Mesoporous silica nanoparticles and related research has noticed a huge growth in the last few years. Some interesting statistics about reports on mesoporous silica are presented in this highlight. After their arrival on the world stage of research these materials have captured several fields of applications including catalyst supports, drug delivery, water purification and their use in bio-materials. Hydrothermal stability, porous structure stability against hydrolysis and suitable organic or bio-functionalization of them for improved biocompatibility are the main issues to be addressed in the near future. Some recent achievements in the synthesis and surface modification of these materials are discussed briefly.

Effect of Multimodal Pore Channels on Cargo Release from Mesoporous Silica Nanoparticles

Mesoporous silica nanoparticles (MSNs) with multimodal pore channels were fully characterized by TEM, nitrogen adsorption-desorption, and DLS analyses. MSNs with average diameter of 200 nm with dual pore channel zones with pore diameters of 1.3ź2.6 and 4 nm were tested for their use in drug delivery application. Important role of the multimodal pore systems present on MSNs on the quantitative release of model drug ibuprofen was investigated. The results obtained revealed that the release profile for ibuprofen clearly shows distinct zones which can be attributed to the respective porous channel zones present on the particles. The fluctuations in the concentration of ibuprofen during the prolonged release from MSNs were caused by the multimodal pore channel systems.

Facile synthesis of magnetic iron oxide nanoparticles and their characterization

Magnetic iron oxide nanoparticles are synthesized by suitable modification of the standard synthetic procedure without use of inert atmosphere and at room temperature. The facile synthesis procedure can be easily scaled up and is of important from industrial point of view for the commercial large scale production of magnetic iron oxide nanoparticles. The synthesized nanoparticles were characterized by thermal, dynamic light scattering, scanning electron microscopy and transmission electron microscopy analyses.

Poly(NIPAM-co-MPS)-grafted multimodal porous silica nanoparticles as reverse thermoresponsive drug delivery system

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Photochemical synthesis of perfluoropolyether (PFPE) nanocomposites containing PFPE oligomer stabilized magnetite nanoparticles

Magnetite nanoparticles were synthesized and their post-synthesis surface modification was carried out with triethoxy terminated perfluoropolyether (PFPE) oligomers. The surface-treated nanoparticles were then dispersed in a UV-curable difunctional methacrylic PFPE oligomer. Thin films prepared from the resulting stable suspensions were photopolymerized. The obtained nanocomposites showed good distribution of the surface-treated magnetite nanoparticles in the polymer matrix. The surface treatment of magnetite nanoparticles with perfluoropolyether oligomers thus was found to be effective in preventing nanoparticle segregation and aggregation, ensuring therefore an increased compatibility with the PFPE matrix.

Polystyrene-block-poly(ethylene oxide) copolymers as templates for stacked, spherical large-mesopore silica coatings: dependence of silica pore size on the PS/PEO ratio

Summary Large-mesopore silica films with a narrow pore size distribution and high porosity have been obtained by a sol–gel reaction of a silicon oxide precursor (TEOS) and using polystyrene-block-poly(ethylene oxide) (PS-b-PEO) copolymers as templates in an acidic environment. PS-b-PEO copolymers with different molecular weight and composition have been studied in order to assess the effects of the block length on the pore size of the templated silica films. The changes in the morphology of the porous systems have been investigated by transmission electron microscopy and a systematic analysis has been carried out, evidencing the dependence between the hydrophilic/hydrophobic ratio of the two polymer blocks and the size of the final silica pores. The obtained results prove that by tuning the PS/PEO ratio, the pore size of the templated silica films can be easily and finely predicted.

Identification of thiol from 11-(9-carbazolyl)-1-undecyl disulfide by NMR spectroscopy and single step coating of gold nanoparticles

Disulfide-functionalized fluorescent derivative of carbozole named 11-(9-carbazolyl)-1-undecyl disulfide (CBZDS) has been synthesized. Proton nuclear magnetic resonance spectroscopy was used to distinguish thiol from its corresponding symmetrical disulfide. Single step synthesis of gold nanoparticles coated with CBZDS was carried out which resulted in stable monolayers of CBZDS on gold nanoparticles. GRAPHICAL ABSTRACT

Packed hybrid silica nanoparticles as sorbents with thermo-switchable surface chemistry and pore size for fast extraction of environmental pollutants

Thermoresponsive poly(N-isopropylacrylamide)-grafted silica nanoparticles (SiNPs) have been synthesized and fully characterized by ATR-FTIR, TGA, HRTEM, BET and DLS analysis. Hybrid solid phase extraction (SPE) beds with tuneable pore size and switchable surface chemistry were prepared by packing the polymer-grafted nanoparticles inside SPE cartridges. The cartridges were tested by checking the thermo-regulated elution of model compounds, namely methylene blue, caffeine and amoxicillin. Extraction of the analytes and regeneration of the interaction sites on the sorbent surface was carried out entirely in water solution by changing the external temperature below and above the lower critical solution temperature (LCST) of the polymer. The results demonstrate that the elution of model compounds depends on the temperature-regulated size of the inter-particle voids and on the change of surface properties of the PNIPAM-grafted nanoparticles from hydrophilic to hydrophobic.