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Alternative Tumor-Targeting Strategies
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
This strategy involves NIR-responsive nanocarriers which become disrupted and release encapsulated anticancer agents when irradiated with Near Infrared energy. For example, researchers have created NIR-responsive micelles by incorporating photochromic groups into the lipid membrane. Upon exposure to NIR, a photoreaction occurs which increase membrane polarity by converting the hydrophobic tails of molecules constituting the micelle into hydrophilic moieties, thus shifting the hydrophilic–hydrophobic balance and causing micellar disruption and release of the encapsulated payload.
Application of Lactic Acid Bacteria in Time-Temperature Integrators
Published in Marcela Albuquerque Cavalcanti de Albuquerque, Alejandra de Moreno de LeBlanc, Jean Guy LeBlanc, Raquel Bedani, Lactic Acid Bacteria, 2020
Amélie Girardeau, Vanessa Biscola, Sophie Keravec, Georges Corrieu, Fernanda Fonseca
Time-temperature integrators are relatively small and cost-effective devices that relay through an irreversible and easily detectable sign, the cumulative effect of time and temperature on the food they are tracking. To be able to integrate all cold chain irregularities during the food’s entire life-cycle, and adjust shelf-life information accordingly, TTIs generally come in the form of labels attached directly on the food’s packaging. These labels can be divided into three main categories, according to their working principles: chemical, physical or biological TTI (Table 1). The first group is comprised of polymerization-based, photochromic-based, and oxidation reaction-based systems (Galagan and Su 2008, Salman et al. 2009, Gou et al. 2010). Physical TTIs encompass devices that are diffusion-based (Monitor Mark®, USA), nanoparticle-based, electronic, and so forth (Zweig 2005, Zeng et al. 2010). Biological TTI are based on enzymatic reactions and/or the use of microorganisms such as yeasts and lactic acid bacteria (Wang et al. 2015). Whatever its working principle is, a TTI’s response is always strongly correlated to changes occurring within the tracked product’s matrix, at a given time-temperature profile. Most of the commercialized TTIs today are of the chemical or physical types (Table 1), but biological TTIs, and more specifically LAB-based TTIs, are the ones that actually reproduce the microbiological reactions that take place in food, leading to spoilage.
Toxicology Studies of Semiconductor Nanomaterials: Environmental Applications
Published in Suresh C. Pillai, Yvonne Lang, Toxicity of Nanomaterials, 2019
T. P. Nisha, Meera Sathyan, M. K. Kavitha, Honey John
The nanoparticles show enhanced ROS generation compared to their bulk counterpart due to their large surface area, which provides more reactive sites for light absorption (Verma et al., 2018). Li et al. (2012b) demonstrated the ROS generation kinetics in seven different metal oxide nanoparticles and their bulk counter parts under UV irradiation. The quantitative measurement of ROS generation was performed using indicators. XTT (2,3-bis(2-methoxy-4-nitro-5-sulfophehyl)-2H-tetrazolium-5-carboxanilide) can be used as an indicator for superoxide radical. p-Chlorobenzoic acid and furfuryl alcohol can be used as indicators for hydroxyl and singlet oxygen, respectively (Li et al., 2012a, 2012b). ZnO nanoparticles can induce cellular toxicity by ROS generation. TiO2 and ZnO generate three types of ROS, namely superoxide radical, hydroxyl radical, and singlet oxygen. Fe2O3 nanoparticles produce significant amounts of superoxide radical and minimal amounts of hydroxyl radical. SiO2 and Al2O3 nanoparticles generate singlet oxygen while CeO2 contributes superoxide radical. Also, ZnO and CuO exhibit toxicity due to the release of toxic ions during irradiation; the metal ion release from particles can be investigated using inductively coupled plasma-mass spectrometry (ICP-MS). Photochromic tungsten oxide nanoparticles show UV-induced toxicity against bacterial and mammalian cells. These nanoparticles show both time- and dose-dependent cytotoxicity due to the decreased dehydrogenase activity (Popov et al., 2018).
Light mediated drug delivery systems: a review
Published in Journal of Drug Targeting, 2022
UV light has been used to influence the contents of amphipathic nano-sized block co-polymers (BCPs) for the sustainable discharge of drugs [23,32,33]. The photoisomerization capability from trans-cis of azobenzene as a part of a BCP is favourable for changes in morphology and subsequently functional properties. A poly (methacrylate) -poly (ethylene oxide)- azobenzene BCP changed its structural moieties when exposed to 365 nm UV illumination [34]. Matyjaszewski's group demonstrated that upon UV irradiation, the polymeric micelle of a BCP was synthesised using a photochromic hydrophobic spiropyran and hydrophilic poly (ethylene oxide) [35]. The micelles formed from an aqueous solution of the BCP were disrupted when illuminated with UV light and subsequently regenerated when visible light was applied to it. The disruption caused by UV light can be a hydrophobic/hydrophilic shift, primary chain degradation, reversible cross-linking, and breakage of block junction [36]. Also, UV light is used in micelles having photocleavable linkers that can be added to the side chain, middle block junction, or form the core of the polymer being used as a carrier. Depending on whether the moieties are hydrophobic, hydrophilic, and, photochromic the substrate can either destabilise partially or disintegrate completely [37,38].
Multicomponent reactions (MCR) in medicinal chemistry: a patent review (2010-2020)
Published in Expert Opinion on Therapeutic Patents, 2021
Hafiza Amna Younus, Mariya Al-Rashida, Abdul Hameed, Maliha Uroos, Uzma Salar, Sobia Rana, Khalid Mohammed Khan
Pang et al. reported the one-pot synthesis of photochromic 6′-amino-substituted spiro-oxazines from 1-nitroso-2-naphthol zinc chelate and indoline base. Spiro-oxazines is one of the most popular photochromic organic compounds known for their potential applications for the design of photo-switchable nonlinear optical devices, luminescent devices, host-guest systems, and enzymatic systems. These photochromic materials have been reported to possess high fatigue resistance and excellent photo-stability. It has also been explored that photochromic spiro-oxazines containing nitrogen heterocycles at the 6′-position possesses remarkable fatigue resistance and substantial bathochromic effects [51]. Rehn et al. reported the 3‐spiro[pyrrolidino‐oxindoles] preparation in high yields from a three‐component reaction between isatin, an α‐amino acid, and a dipolarophile [52]. The multicomponent reaction using aryne along with the utilization of N-heteroaromatic compounds as the nucleophilic trigger has led the development of novel biologically active transition metal-free synthesis of spiro-oxazine and indolinone compounds in high yield and selectivity (Scheme 7,8).
Potential oral probiotic Lactobacillus pentosus MJM60383 inhibits Streptococcus mutans biofilm formation by inhibiting sucrose decomposition
Published in Journal of Oral Microbiology, 2023
Mingkun Gu, Joo-Hyung Cho, Joo-Won Suh, Jinhua Cheng
The hemolytic activity of L. pentosus MJM60383 and LGG were assessed using MRS agar plates added 5% defibrinated sheep blood. L. pentosus MJM60383 was streaked on plates and incubated at 37°C for 24 h. Hemolytic activity was observed with transmitted light and determined by the photochromic properties around the colonies.