Nanomaterials for Theranostics: Recent Advances and Future Challenges *
Valerio Voliani in Nanomaterials and Neoplasms, 2021
The cell membrane is negatively charged because of the presence of phospholipids. Therefore, the positive surface charge of nanoparticles enables highly efficient binding to the cell surface through electrostatic interactions. Positively charged nanoparticles can attach negatively charged DNA molecules via electrostatic interactions and act as a gene-delivery vector [60, 6,164, 65, 67–71, 73]. In particular, amine groups protect genes from nuclease degradation, facilitate cellular internalization, and induce DNA delivery to the nucleus by membrane rupturing via the proton sponge effect. PEI is currently the most preferred synthetic polymer material for gene delivery because it demonstrated high gene transfer activity [62, 63, 66, 72]. PEI does not require the use of an exogenous endosomolytic agent because of its high amine density, allowing PEI to escape from the endocytic pathway of the host via a strong proton sponge mechanism. However, the toxicity of PEI needs to be reduced before it can be used in clinical applications.
Fats, Fatty Acids, and Lipids
Luke R. Bucci in Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Phospholipids are similar to triglycerides, but one end carbon of the glycerol backbone has a phosphate group instead of a fatty acid (phosphatide). The phosphate group is usually bound to one of the following: choline, ethanolamine, serine, or inositol to form a phospholipid. Sterols are hydrocarbon ring structures with varying amounts of unsaturation. Steroids (polyunsaturated sterols) have rigid, planar structures. Many modifications of sterols and steroids are encountered, with esterification, hydroxylation, oxidation, and conjugation being more frequently observed. Common sterols and steroids are cholesterol, p-sitosterol, bile acids, estrogens, progestins, testosterones, corticosteroids, and mineralosteroids. Dolichols are long-chain alcohols used in carbohydrate transport and metabolism in cells. Quinones are exemplified by coenzyme Q10, an extremely important link in the conversion of foodstuffs into cellular energy. Quinones possess substituted rings, usually with hydrocarbon side chains, and are present inside of cell organelle membranes.
Atherosclerosis
George Feuer, Felix A. de la Iglesia in Molecular Biochemistry of Human Disease, 2020
Phospholipases are found in small amounts in membranes and they are relevant to atherosclerosis. Phospholipases can degrade lipoproteins in the blood or in the cell.168,169,519These enzymes play a role in thrombosis through control of the synthesis of prostaglandins and thromboxanes. The action of phospholipase A2 on phospholipid substrates leads to free fatty acids and lysophosphatidic acid. In most naturally occurring phospholipids, unsaturated fatty acids occupy position 2 of the glycerol skeleton which is cleared by phospholipase A2. This enzyme, therefore is able to release arachidonic acid which is the immediate precursor of potent substances such as prostaglandins and thromboxanes. The other product of hydrolysis, lysophosphatide, exerts a detergent action and promotes lysis of membranes.
Systematic review on activity of liposomal encapsulated antioxidant, antibiotics, and antiviral agents
Published in Journal of Liposome Research, 2022
Reshna K. R, Preetha Balakrishnan, Sreerag Gopi
Phospholipid contains two major categories including glycerophospholipids and sphingolipids (categorized into sphingomyelin and glycolipid). The glycerophospholipids are considered as a backbone of liposome. The chemical structure of glycerophospholipids consists of a hydrophilic head group and a hydrophobic side chain. Different glycerophospholipids are obtained as a result of head group variation, for example, phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidic acid (PA), phosphatidylglycerol (PG), and cardiolipin (CL). Decreased nonpolar moieties with varying lengths produce a wide range of different glycerophospholipids, such as dimyristoyl, dipalmitoyl, and distearoyl PC, among others. Furthermore, the type of bond formed between glycerol and aliphatic chains (ether or ester) results in the formation of distinct glycerophospholipids.
Genistein prevents the decrease in ganglioside levels induced by amyloid-beta in the frontal cortex of rats
Published in Neurological Research, 2022
Fernanda dos Santos Petry, Juliana Bender Hoppe, Caroline Peres Klein, Bernardo Gindri dos Santos, Régis Mateus Hözer, Christianne Gazzana Salbego, Vera Maria Treis Trindade
The AD pathogenesis is closely related to changes in the lipid homeostasis, which can severely affect the physicochemical properties of cell membranes [4,5]. Gangliosides are sialic acid-containing glycosphingolipids, present in high concentrations in neuronal cell membranes, which play important roles in memory formation, neuritogenesis and synaptic transmission. Moreover, they are involved in cell differentiation and growth, ion channel modulation, and intercellular signaling [6]. Phospholipids exert structural functions in the membrane, also participating in cell signaling. Cholesterol, in turn, is an essential component for the structure and function of cell membranes, modulating their physicochemical properties and contributing to the formation of lipid rafts, specialized membrane microdomains that compartmentalize cellular processes [7]. Increasing evidence indicates that the Aβ peptide can alter the composition and structure of cell membranes, impairing neuronal functions [8,9].
Surface-modified polymeric nanoparticles for drug delivery to cancer cells
Published in Expert Opinion on Drug Delivery, 2021
Arsalan Ahmed, Shumaila Sarwar, Yong Hu, Muhammad Usman Munir, Muhammad Farrukh Nisar, Fakhera Ikram, Anila Asif, Saeed Ur Rahman, Aqif Anwar Chaudhry, Ihtasham Ur Rehman
Cell membrane functions as the main barrier for inward and outward movement of bio-entities [33]. Similarly, drug-loaded polymeric nanoparticles are also needed to cross the cell membrane to exhibit their efficiency. The composition, morphology, and functions of cell membrane have attracted scientists to fabricate nanoparticles, whose surfaces mimic cell membrane (Figure 3a). The cell membrane is composed of a phospholipid bilayer with embedded proteins and carbohydrates. Phospholipids consist of hydrophobic phosphate group-containing head linked to the hydrophobic tail of fatty acids. These phospholipids self-assemble into bilayers with hydrophilic regions facing toward outside and inside of the cell, while hydrophobic tails of phospholipids face each other. The incorporation of cholesterol and proteins enhances the stability of the cell membrane. Membrane proteins are inserted throughout the cell membrane asymmetrically. They are arranged in a way that their exterior surfaces can act as receptors for signaling molecules, whereas interior sides change their conformation in response to the binding signal. In some cases, membrane carbohydrates, in the form of glycolipids, work as recognition sites for proteins [34]. Research on biologically inspired nanoparticles has revealed that surface modification of nanoparticles with lipid bilayer or protein/carbohydrate embedding enhances the efficacy of drug-loaded nanoparticles [35], for instance increase in circulation time, improved biocompatibility, low toxicity and immunogenicity [36] and enhanced stability [37].
Related Knowledge Centers
- Alcohol
- Choline
- Docosahexaenoic Acid
- Eicosapentaenoic Acid
- Ethanolamine
- Fatty Acid
- Glycerol
- Phosphate
- Lipid
- Omega-3 Fatty Acid