China
Africa
Explore chapters and articles related to this topic
Hybrid Nanosystems
Published in Carla Vitorino, Andreia Jorge, Alberto Pais, Nanoparticles for Brain Drug Delivery, 2021
Pablo Vicente Torres-Ortega, Laura Saludas, Jon Eneko Idoyaga, Carlos Rodríguez-Nogales, Elisa Garbayo, María José Blanco-Prieto
Some strategies have recently been developed to explore the potential of HNs based on inorganic nanomaterials combined with organic matrices in neuroprotective treatments for AD. For instance, magnetic particles produced by magnetospirillum bacteria conjugated to carbon nanotubes have demonstrated tremendous potential for AD treatment [26]. These hybrids have a neuroprotective effect due to their intrinsic peroxidase-like catalytic activity, which reduces the reactive oxygen species formation, and also thanks to their capacity to inhibit the formation of β-amyloid when interfering with AB peptides in the Aβ fibril-induced neurotoxic conditions in SH-SY5Y cells [26].
Optimizing Reporter Gene Expression for Molecular Magnetic Resonance Imaging
Published in Shoogo Ueno, Bioimaging, 2020
Qin Sun, Frank S. Prato, Donna E. Goldhawk
Since most magnetosome proteins are membrane-bound,45 their expression in any cell type involves a lipid bilayer. In prokaryotes, this implicates the cell membrane; however, in eukaryotes, integral membrane proteins are routed through vesicles emanating from the Golgi apparatus and will remain within the cytoplasmic compartment20 unless directed otherwise by specific membrane localization signals. Regardless of cell type, iron biomineralization is confined to a membrane-enclosed compartment and this is an important protective mechanism, built into the magnetosome blueprint, for avoiding iron cytotoxicity. In species of Magnetospirillum, the absence of MamI, MamL, or MamB produces neither magnetosome vesicle nor iron biomineral,43 establishing the importance of these proteins in key steps of magnetosome synthesis. In contrast, deletion of MamE interferes with biomineralization but still permits vesicle formation. Based on these results, magnetosome proteins that assemble at the membrane are probably not all directly involved in iron-handling. A no less important, regulatory role is held by proteins that designate the membrane location for initiation and elaboration of the iron biomineral. This notion is consistent with cryotomographic images of MTB, revealing both empty magnetosome vesicles as well as those containing biominerals of varying sizes within a single magnetosome chain.49,50Figure 9.1 therefore is a working hypothesis that implicates MamI, MamL, and MamB in the initial designation of a magnetosome membrane.
MagA increases MRI sensitivity and attenuates peroxidation-based damage to the bone-marrow haematopoietic microenvironment caused by iron overload
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2018
Yingying Shen, Cunjing Zheng, Yunpu Tan, Xinhua Jiang, Li Li
The iron concentration is expected to influence MRI signals, so several iron-related genes have been studied as “MRI markers”, including magA. In Magnetospirillum magneticum species AMB-1, magA was initially believed to participate in magnetosome synthesis [14]. More recently, MagA has been recognized as a nonessential magnetosome protein [15] located outside the magnetosome genomic island [16,17]. Typically, a magnetosome consists of a lipid bilayer surrounding a magnetite crystal (Fe3O4 in AMB-1). The magA gene encodes an integral membrane protein with homology to the bacterial H+/Fe2+ antiporter family of proteins coupled to ATPase [18,19]. With MagA expressed in the Escherichia coli, cells have been shown to transport Fe2+ in an energy-dependent manner, leading to accumulation of Fe2+ in the vesicle [14,18].
Bioengineered smart bacterial carriers for combinational targeted therapy of solid tumours
Published in Journal of Drug Targeting, 2020
Siamak Alizadeh, Abolghasem Esmaeili, Abolfazl Barzegari, Mohammad A. Rafi, Yadollah Omidi
Bacterial microrobots (BMRs), so-called bacteriobots, have been developed based on the intrinsic features of bacteria, including chemotaxis, phototaxis and magnetotaxis [128]. They can be engineered to be responsive to various stimuli, including the external chemical attractants, ultraviolet light and electromagnetic actuation stimuli [63]. Bacteriobots are fabricated through the vigorous attachment of various biocompatible and biodegradable ingredients to appropriate bacteria to create stimuli-responsive bacterial-based microrobots from which the loaded drugs can be released in a controlled manner [128]. As shown in Figure 7, BMRs are mainly composed of bacteria as a sensor and microbead containing therapeutic agents and an actuator to direct them to their target sites and induce the intended biological impacts [63]. In comparison with other passive and active targeted DDSs as well as controlled-release and pulsatile delivery systems, owing to their advantages, various types of biomedical microrobots have recently been developed [129]. Several bacterial strains with high motility have been used for microrobot actuation, including Escherichia coli, Serratia marcescens, Salmonella typhimurium and magnetotactic bacteria (MTB) such as Magnetospirillum gryphiswaldense strain MSR-1 [129,130]. The success paradigm was the use of paclitaxel-loaded liposomal micro-cargo in combination with tumour-targeting Salmonella typhimurium bacteria for targeting the breast cancer cell line (4T1). Based on this finding, the drug-loaded bacteriobots revealed strong tumour targeting and killing potentials [131].
Glioblastoma multiforme: a glance at advanced therapies based on nanotechnology
Published in Journal of Chemotherapy, 2020
Vahid Rezaei, Amir Rabiee, Farzaneh Khademi
Due to the destructive effects of the thermotherapy (45- 41 °C) on the plasma membrane, damage to DNA and protein denaturation, and changes in micro-environmental pH, it induces apoptosis in the tumor cells.14,83–85 For localized GBM hyperthermia, magnetic fields and laser were applied. GNPs and magnetic NPs (MNPs) are two main NPs that are used extensively in HT.84 The first use of MNPs for cancer HT was done in 1957.83,84,86 Three major classes of iron NPs, namely magnetite, maghemite and hematite especially SPIONs, are frequently used in HT due to biocompatibility and low toxicity.84 On the other hand, utilization of the alternating magnetic field (AMF) as a heat inducer of NPs, IONs coated by aminosilane, dextran, and also magnetosome extraction from Magnetospirillum gryphiswaldense (MSR-1) bacteria coated by poly-L-lysine (PLL) can be useful for hyperthermia.14,85 Generally, thermal energy is produced due to Néel and Brownian relaxations85 and hysteresis loss.83,85 The μ-oxo N,N’-bis(salicylidene)ethylenediamine iron [Fe(Salen)] NPs potentially increased the GBM cell death through reactive oxygen species (ROS) process.14 Limitations of magnetic HT include optimization dose of MNPs, toxicity, inappropriate heat distribution, untargeted MNPs injected, and lack of device for measuring local temperature.84 Carbon nanotubes (CNTs) with near-infrared radiation (NIR) can reduce the tumor size, and particularly eradicate the CSCs.6