1,084 research outputs found
Nanocapsules with stimuli-responsive moieties for controlled release employing light and enzymatic triggers
No full textThe development of stimuli-responsive nanomaterials, that possess tailored functional properties for the release of specific compounds, is of particular interest. To this extent, controlling the release of molecules at the desired target is an important parameter to regulate chemical and/or biological reactions at a more profound level in a wide variety of applications. In the present work, we report on the development of dual-responsive thiourethane-urethane nanocapsules synthesizedviaan interfacial polymerization reaction executed at the droplet interface using the inverse miniemulsion technique. Evidenceviamorphological and controlled release investigations indicate that our nanocapsules are able to encapsulate hydrophilic compounds with high efficiency in their aqueous core and allow for its selective release upon exposure to UV light and the enzyme esterase. Moreover, we demonstrate the efficient encapsulation of the fragrance molecule geranyl acetate and the anticancer drug doxorubicin. For the latter, we demonstrate its apoptotic effect after being released in MCF 7 breast cancer cells. Overall, these nanocapsules can be used for a wide variety of applications where a selective release of the payload is desired.S. S. is an SB PhD Fellow at the FWO (Research Foundation Flanders). S. K. P. acknowledges BOF funding from Hasselt University. This work is supported by Hasselt University and the Research Foundation Flanders (FWO Vlaanderen; Hercules project AUHL/15/2 - GOH3816N). The authors are thankful to Prof. M. Van Bael for access to the DLS device.Pramanik, SK; Ethirajan, A (corresponding author), Hasselt Univ, Inst Mat Res IMO, Wetenschapspk 1 & Agoralaan D, B-3590 Diepenbeek, Belgium; IMEC, Associated Lab IMOMEC, Wetenschapspk 1, B-3590 Diepenbeek, Belgium;
CSIR Cent Salt & Marine Chem Res Inst, Bhavnagar 364002, Gujarat, India.
[email protected]; [email protected]
Redox-Responsive Nanocapsules for the Spatiotemporal Release of Miltefosine in Lysosome: Protection against Leishmania
No full textLeishmaniasis, a vector-borne disease, is caused by intracellular parasite Leishmania donovani. Unlike most intracellular pathogens, Leishmania donovani are lodged in parasitophorous vacuoles and replicate within the phagolysosomes in macrophages. Effective vaccines against this disease are still under development, while the efficacy of the available drugs is being questioned owing to the toxicity for nonspecific distribution in human physiology and the reported drug-resistance developed by Leishmania donovani. Thus, a stimuli-responsive nanocarrier that allows specific localization and release of the drug in the lysosome has been highly sought after for addressing two crucial issues, lower drug toxicity and a higher drug efficacy. We report here a unique lysosome targeting polymeric nanocapsules, formed via inverse mini-emulsion technique, for stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line. A benign polymeric backbone, with a disulfide bonding susceptible to an oxidative cleavage, is utilized for the organelle-specific release of miltefosine. Oxidative rupture of the disulfide bond is induced by intracellular glutathione (GSH) as an endogenous stimulus. Such a stimuli-responsive release of the drug miltefosine in the lysosome of macrophage RAW 264.7 cell line over a few hours helped in achieving an improved drug efficacy by 200 times as compared to pure miltefosine. Such a drug formulation could contribute to a new line of treatment for leishmaniasis.A. Das acknowledges SERB (India) Grants (CRG/2020/000492 and JCB/2017/000004) and DBT Grant (BT/PR22251/NNT/28/1274/2017) for supporting this research. N. Mukherjee acknowledges SERB (India) Grant PDF/2016/001437 and K. Das acknowledges the grant EMR/2015/001674 for supporting this research. Financial support from DST (DST/INSPIRE/03/2017/002477) is acknowledged by R.T. This manuscript bears CSMCRI registration no 7/2021.Pramanik, SK (corresponding author), CSIR Cent Salt & Marine Chem Res Inst, Bhavnagar 364002, Gujarat, India.
Mukherjee, N (corresponding author), CSIR Indian Inst Chem Biol, Canc Biol & Inflammatory Disorder Div, Kolkata 700032, India.
Chattopadhy, S (corresponding author), BITS Pilani, Pilani 403726, Goa, India.
Das, A (corresponding author), Indian Inst Sci Educ & Res Kolkata, Mohanpur 741246, W Bengal, India.
[email protected]; [email protected]; [email protected]
PEGylating poly(p-phenylene vinylene)-based bioimaging nanoprobes
No full textHypothesis: Conjugated polymer nanoparticles (CNPs) have attracted considerable attention within bioimaging due to their excellent optical properties and biocompatibility. However, unspecific adsorption of proteins hampers their effective use as advanced bioimaging probes. Controlled methodologies made possible tailor-made functional poly(p-phenylene vinylene), enabling one-pot synthesis of CNPs containing functional surface groups. Hence, it should be feasible to PEGylate these CNPs to tune the uptake by cell lines representative for the brain without imparting their optical properties. Experiments: CNPs consisting of the statistical copolymer 2-(50-methoxycarbonylpentyloxy)-5-methoxy-1,4-phenylenevinylene and poly(2-methoxy-5-(30,70-dimethoxyoctyloxy)-1,4-phenylenevinylene) were fabricated by miniemulsion solvent evaporation technique. Surface carboxylic acid groups were used to covalently attach amine-terminated polyethylene glycol (PEG) of different molecular weights. We investigated the effect of grafting CNPs with PEG chains on their intrinsic optical properties, protein adsorption behavior and uptake by representative brain cell lines. Findings: PEGylation did not affect the optical properties and biocompatibility of our CNPs. Moreover, a significant decrease in protein corona formation and unspecific uptake in central nervous system cell lines, depending on PEG chain length, was observed. This is the first report indicating that PEGylation does not affect the CNPs role as excellent bioimaging tools and can be adapted to tune biological interactions with brain cells. (C) 2020 Elsevier Inc. All rights reserved.Support for confocal microscopy was given by Prof. dr. Marcel Ameloot and Dr. Hannelore Bove. Cells were kindly provided by Prof. dr. Annelies Bronckaers, Dr. Jo Mailleux and dra. Jasmine Vanmol. Technical support was given by Huguette Penxten, Christel Bocken and Erik Royackers. Dr. Neomy Zaquen is acknowledged for the synthesis of the conjugated polymers. MP is grateful for funding from the IWT (Agentschap voor Innovatie door Wetenschap en Technologie). SS is an SB PhD Fellow at the Research Foundation Flanders (FWO). The work was funded by the Belgian Charcot Foundation. TJ is grateful for funding from the FWO in the form of an Odysseus grant. This work was supported by Hasselt University and the Research Foundation Flanders (FWO Vlaanderen; Hercules project AUHL/15/2 -GOH3816N). Additional support from BELSPO in the form of the interuniversity attraction pole (IAP) program P7/05: Functional Supramolecular Systems is kindly acknowledged. We further acknowledge the Hercules Foundation for the project (LC-MS@UHasselt: Linear Trap QuadrupoleOrbitrap mass spectrometer.Ethirajan, A (corresponding author), Hasselt Univ, Inst Mat Res, Wetenschapspk 1, B-3590 Diepenbeek, Belgium.
[email protected]
Modulating the interaction between gold and TiO2 nanowires for enhanced solar driven photoelectrocatalytic hydrogen generation
No full textThe interaction strength of Au nanoparticles with pristine and nitrogen doped TiO2 nanowire surfaces was
analysed using density functional theory and their significance in enhancing the solar driven photoelectrocatalytic
properties was elucidated. In this article, we prepared 4-dimethylaminopyridine capped Au
nanoparticle decorated TiO2 nanowire systems. The density functional theory calculations show {101}
facets of TiO2 as the preferred phase for dimethylaminopyridine–Au nanoparticles anchoring with a binding
energy of 8.282 kcal mol1
. Besides, the interaction strength of Au nanoparticles was enhanced
nearly four-fold (35.559 kcal mol1
) at {101} facets via nitrogen doping, which indeed amplified the Au
nanoparticle density on nitrided TiO2. The Au coated nitrogen doped TiO2 (N–TiO2–Au) hybrid electrodes
show higher absorbance owing to the light scattering effect of Au nanoparticles. In addition, N–TiO2–Au
hybrid electrodes block the charge leakage from the electrode to the electrolyte and thus reduce the
charge recombination at the electrode/electrolyte interface. Despite the beneficial band narrowing effect
of nitrogen in TiO2 on the electrochemical and visible light activity in N–TiO2–Au hybrid electrodes, it
results in low photocurrent generation at higher Au NP loading (3.4 107 M) due to light blocking the
N–TiO2 surface. Strikingly, even with a ten-fold lower Au NP loading (0.34 107 M), the synergistic effects
of nitrogen doping and Au NPs on the N–TiO2–Au hybrid system yield high photocurrent compared to
TiO2 and TiO2–Au electrodes. As a result, the N–TiO2–Au electrode produces nearly 270 mmol h1 cm2
hydrogen, which is nearly two-fold higher than the pristine TiO2 counterpart. The implications of these
findings for the design of efficient hybrid photoelectrocatalytic electrodes are discussed.
IntroducGlobal Research Laboratory (GRL) Program through the National Research Foundation of Korea (NRF) - Ministry of Science. K20704000003TA050000310
Japan Society for the Promotion of Science (JSPS)
University Jaume I. P1.1B2014-51
Government of the Russian Federation. 074-U0
Intercostal drainage tube or intracardiac drainage tube?
No full textAlthough insertion of chest drain tubes is a common medical practice, there are risks associated with this procedure, especially when inexperienced physicians perform it. Wrong insertion of the tube has been known to cause morbidity and occasional mortality. We report a case where the left ventricle was accidentally punctured leading to near-exsanguination. This report is to highlight the need for experienced physicians to supervise the procedure and train the younger physician in the safe performance of the procedure
Power relations Vs Personal Relations in the Selected Translations of O.Chandu Menon’s Indulekha
No full textThe novel has three English translations. The first English version was by John Willoughby Francis Dumergue, a friend of O. Chandu Menon. The latest one was by Dr. Anitha Devassia. The novel had several novelties in terms of theme and technique though Chandu Menon was trying to ‘translate’ an alien genre to Malayalam literature. Anitha Devasia’s translation came more than hundred years after the publication of the original and Dumergue’s translation. This paper intends to analyze the two translations to identify the translator more representative of the author using Bourdieu’s concept of habitus. Bourdieu defines habitus as “a general, transposable disposition, which carries out a systematic, universal appreciation - beyond the limits of what has been directly learnt- of the necessity inherent in learning conditions
Fibrous dysplasia-recent concepts
No full textFibrous dysplasia (FD) is a benign intramedullary fibro-osseous lesion. FD is a bone developmental anomaly characterized by replacement of normal bone and marrow bone by fibrous tissue. It involves any of the bones as single lesion (monostotic) or in multiple bone lesions (polyostotic) or all of the skeletal system (panostotic). Long bones are most commonly involved, which mostly identified incidentally and clinically appears asymptomatic. Clinical, radiographical and histopathological findings will help in confirming the lesion. There are many treatment option available, but still management of FD remains challenging
P17-09: Polystyrene microplastics of varying sizes and shapes induce distinct redox and mitochondrial stress responses in a Caco-2 monolayer
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