G protein–coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein–linked receptors (GPLR), constitute a large protein family of receptors that detect molecules outside the cell and activate internal signal transduction pathways and, ultimately, cellular responses. Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times. G protein–coupled receptors are found only in eukaryotes, including yeast, choanoflagellates, and animals. The ligands that bind and activate these receptors include light-sensitive compounds, odors, pheromones, hormones, and neurotransmitters, and vary in size from small molecules to peptides to large proteins. G protein–coupled receptors are involved in many diseases and are also the target of approximately 34% of all modern medicinal drugs.
2. HISTORY & PREPARATIONS OF NANOPARTICLES Tibrewal Richa, Mishra Kavi Shankar
A nanoparticle (or nanopowder, or nanocluster, or nanocrystal) is a microscopic particle containing at least one dimension less than 100 Nm.4 Nanoparticles are particles between 1 and 100 nanometers (nm) in size, with the surrounding interfacial layer. Integral parts of nanoscale subject matter, all its properties are profoundly influenced by the interfacial layer. Usually, the interfacial layer is made up of ions, inorganic and organic molecules. Organic molecules that cover inorganic nanoparticles are known as stabilizers, ligands of capping and surface or passivating agents. In nanotechnology, a particle is characterized as a small object that acts in terms of its transport and properties as a whole. Particles are additionally graded according to their diameter. Nanotechnology refers to the production and use of materials whose nanoscale components exist and, by definition, are up to 100 nm in size. Nanotechnology investigates both electrical, optical, and magnetic activity, and molecular and submolecular structural behavior. It has the ability to revolutionize a range of methods and procedures in medical and biotechnology to make them compact, simpler, safer, and easier to administer.