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Characterization Techniques of Nanoparticles Applied in Drug Delivery Systems
Published in Bhaskar Mazumder, Subhabrata Ray, Paulami Pal, Yashwant Pathak, Nanotechnology, 2019
Vipin Kumar Sharma, Daphisha Marbaniang
Liposomes are vesicular structures with an aqueous core surrounded by a hydrophobic lipid bilayer, created by the extrusion of phospholipids. Solutes, such as drugs, in the core cannot pass through the hydrophobic bilayer, however hydrophobic molecules can be absorbed into the bilayer, enabling the liposome to carry both hydrophilic and hydrophobic molecules. The lipid bilayer of liposomes can fuse with other bilayers such as the cell membrane, which promotes the release of its contents, making them useful for drug delivery and cosmetic delivery applications. Liposomes that have vesicles in the range of nanometers are also called nanoliposomes (Cevc, 1996; Zhang and Granick, 2006). The unique structure of liposomes, a lipid membrane surrounding an aqueous cavity, enables them to carry both hydrophobic and hydrophilic compounds without chemical modification. In addition, the liposome surface can be easily
Biomaterials and Material Testing
Published in Paul H. King, Richard C. Fries, Arthur T. Johnson, Design of Biomedical Devices and Systems, 2018
Paul H. King, Richard C. Fries, Arthur T. Johnson
The first NP platform was the liposomes. Liposomes were first described in 1965 as a model of cellular membranes. Since then, liposomes have moved from a model in biophysical research to one of the first NP platforms to be applied for gene and drug delivery. Liposomes are spherical vesicles that contain a single or multiple bilayered structure of lipids that self-assemble in aqueous systems. Unique advantages imparted by liposomes are their diverse range of compositions, abilities to carry and protect many types of biomolecules, as well as their biocompatibility and biodegradability. These advantages have led to the well-characterized and wide use of liposomes as transfection agents of genetic material into cells (lipofection) in biology research Lipofection generally uses a cationic lipid to form an aggregate with the anionic genetic material. Another major application of liposomes is their use as therapeutic carriers since their design can allow for entrapment of hydrophilic compounds within the core and hydrophobic drugs in the lipid bilayer itself. To enhance their circulation half-life and stability in vivo, liposomes have been conjugated with biocompatible polymers such as PEG. Liposomes can also be functionalized with targeting ligands to increase the accumulation of diagnostic and therapeutic agents within desired cells. Today, there are twelve clinically approved liposome-based therapeutic drugs.
Physiological basis and concepts of electromyography
Published in Kumar Shrawan, Mital Anil, Electromyography in Ergonomics, 2017
The basic structure of a cell membrane is shown in Figure 2.1. The membrane comprises a double layer of phospholipids. Both surfaces of this layer are covered with proteins. In addition, proteins are embedded into the lipid bilayer, permeating it either fully or partially. The bilayer structure of the cell membrane and the properties of the lipid molecules are important for the means by which an exchange between the intracellular and the interstitial compartments is restricted. Lipid molecules are elongated and unsymmetrical in structure. They possess a polar head and a non-polar tail (Eckert and Randall, 1983). The polar heads are hydrophilic, i.e. water soluble, whereas the non-polar tails are hydrophobic, i.e. water insoluble. Within the double layer the lipid molecules are positioned in such a way that the hydrophobic ends face each other in the middle of the membrane whereas the hydrophilic ends are immersed in the aqueous solutions present in the intracellular and extracellular spaces. The hydrophobic property of the tails in the inner lipid layer means that the membrane represents an almost insuperable barrier for water, water-soluble molecules, and ions.
Carbon nanomaterials: a new way against tuberculosis
Published in Expert Review of Medical Devices, 2019
Flavio De Maio, Valentina Palmieri, Marco De Spirito, Giovanni Delogu, Massimiliano Papi
Lipid-based systems, classically named liposomes and solid lipid nanoparticles (SLNs), have been largely studied for TB treatment. Liposomes are vesicles with a hydrophilic core enclosed in a lipid bilayer mainly used for drug delivery. Liposomal RIF or INH [59,61–64], PZA [65], rifabutin [66], amikacin [67,68] and clofazimine [69] have been produced. A case report of a patient with severe multidrug-resistant tuberculosis described a well toleration of liposomal amikacin with clinical improvements [68]. Liposomes can be prepared by a variety of lipid compositions, with different size and then stabilized by molecules such as cholesterol to alter their in vivo biodistribution. In the work of Deol and colleagues [70], a double strategy was proposed to increase the liposome accumulation in the lungs: (a) the inclusion of molecules in liposomes such as O-stearylamylopectin, dicetylphosphate, monosialoganglioside, distearylphosphatidylethanolamine-polyethylene glycol or (b) pre-administration of phosphatidyl-choline and cholesterol liposomes before the injection of lung specific stealth liposomes. Similar to liposomes, the niosomes have been also analyzed for TB treatment. Niosomes are liposomes with the addition of nonionic surfactant which stabilizes them in circulation [71]. Niosomes loaded with ethambutol [72] and rifampicin [73] have been tested in vivo.
A novel insight to screen the optimal spray-drying protectants and parameters for manufacturing lactic acid bacteria preparations
Published in Drying Technology, 2020
Zhuo Zhang, Sen Peng, Xiaoqi Sun, Yu Jie, Hongfei Zhao, Baoqing Zhu, Piotr Dziugan, Bolin Zhang
Liposomes with a lipid bilayer have been designed to simulate cell membranes as a vesicle to embed and deliver drugs.[23,24] β-galactosidase (β-gal) is one of the most important enzymes in probiotics. Its activity is susceptible to heat, and it is a reflection of fermentation capacity and strain cell membrane permeability.[25,26] Our previous study has shown that it is feasible to employ a β-gal liposome model to rapidly screen cryoprotective agents for LAB.[27]
Inhibitory effects of intact silkworm sericin on bacterial proliferation
Published in The Journal of The Textile Institute, 2021
Erica Matsumoto, Keiko Takaki, Rina Maruta, Hajime Mori, Eiji Kotani
Our results also showed that intact sericin affected the colony size of E. coli and S. enterica, but had no effect on colony growth in S. aureus and B. subtilis (Figures 2 and 3; Table 2). E. coli and S. enterica are examples of Gram-negative bacteria, which have the outer membrane outside the cell wall, with a thin peptide glycan layer. Their outer membrane is a lipid bilayer composed of phospholipids, lipopolysaccharides, and transmembrane lipoproteins, such that hydrophilic molecules can move in and out of the cell body through pores (Silhavy et al., 2010; Nikaido, 2003). However, unlike Gram-negative bacteria, Gram-positive bacteria, including S. aureus and B. subtilis, have a thicker peptide glycan layer, which is a very thick network structure consisting of N-acetyl glucosamine and N-acetyl muramic acid (Silhavy et al., 2010). It is known that higher metabolic activities are necessary to actively import higher molecular weight substances through this thick peptide glycan layer than through the thinner layer associated with Gram-negative bacteria (Silhavy et al., 2010, p. 15; Meroueh et al., 2006). Thus, the lack of an effect of sericin on the growth of Gram-positive bacteria is likely due to the thick peptide glycan layer outside the cytoplasmic membrane of these bacteria, which would hinder the passage of sericin proteins of varying molecular sizes (Figure 1). The amino acid composition of intact sericin and the degraded commercial sericin were shown to be very similar (Table 1), although the results from SDS-PAGE showed quite different banding patterns (reflecting differences in size) between intact sericin and the degraded sericin (Figure 1). The intact sericin slowed the growth in Gram-negative bacteria, suggesting the importance of the high molecular weight proteins in intact sericin solution.