the effect of polylactic acid support in stability and electrical field of heterocyclic coupled hexa peptide nano systems: a novel strateu to drug delivery

biological materials. recently. are the building blocks of several self-assembling peptide and protein systems.the main challenge in molecular self-assembly is to design molecular building blocks that can undergospontaneous organization. these cyche peptides were produced by an alternating fl'ell number of d- and laminoacids.which interact through non-covalent interactions co an array of selfassembleil nanotubes.physicochemical properties of structure of some peptide nanodngs in couple form. with the support of abiocompatible and biodegradable polylactic acid. (pla) have been calculated by quantum mechanicalcalculations within the onsager self-consistent reaction field (scri) model using a hartree-fock method(rhf) at the rh tisto-30 (5d-7f) level in water medium at 310 k. four rings, cycle g(d-gly-l-glyhj (a),cyclo (d-gly-l-ala)3] (b). cyclo [-(d-gly-l-aminogly)s (c). cycle [-(d-oly-l-hydroxygly)3] (0). aredesigned in a couple form and geometrically optimized near by the 1.3 and 6 polylactic acid. (pla) support,with non-covalent interaction. analyzing the geometncal position of polylactic acid chain, around the couplednano system, results the pla is preferred to stand in the distance of 4 a of aa, 2-5 a for ab and 12 a or bothbc and al'. the stability of some systems, could not be affected in the wide range of distances such as. ac ini-10 a, bb in 3-12 a. cc in 4-12 a and both cd and do in the 2-12 a. do nano system presents the best inall conditions where cc. bd and ad couples stand in the second rank bc and ac stand after. the stability ofaa, ab and bb are less. although no effect in behavior of nano systems are seen, increasing the number ofsupports make them more stable. conung near and go far, the pla aflbcts the dipole moment of system, deeply,