Title
Peptide-poly(tert-butyl methacrylate) conjugate into composite micelles in organic solvents versuspeptide-poly(methacrylic acid) conjugate into spherical and worm-like micelles in water: Synthesis and self-assembly
Author
Anupam Saha, Somdeb Jana, Tarun K. Mandal
Year
2016
Journal
Journal of Polymer Science Part A: Polymer Chemistry
Abstract
Peptide–polymer conjugates are versatile class of biomaterials composed of a peptide block covalently linked with a synthetic polymer block. This report demonstrates the synthesis of peptide-poly(tert-butyl methacrylate) (Peptide-PtBMA) conjugates of varying molecular weights via a “grafting from” atom transfer radical polymerization (ATRP) technique using as-synthesized peptide-based initiator in toluene. Peptide-PtBMA conjugate is soluble in many organic solvents and undergoes self-assembly into micro/nanospheres in DMF/THF as observed from both FESEM and DLS results. The conjugate micro/nanospheres are nothing but the composite micelles formed by the secondary aggregation of primary micelles generated initially in these organic solvents. The hydrolysis of tert-butyl groups of Peptide-PtBMA conjugate leads to the formation of peptide-poly(methacrylic acid) (Peptide-PMA) conjugate. The circular dichroism (CD) analysis exhibits the presence of β-sheet conformation of peptide moiety in synthesized conjugates. The formed Peptide-PMA conjugate is soluble in water and owing to its amphiphilic character, the conjugate molecules self-assemble into spherical micelles as well as worm-like micelles upon increasing the concentration of conjugate in water. However, the sodium salt of Peptide-PMA conjugates (Peptide-PMAS) self-assembles into only spherical swollen micelles in water at higher (pH ∼10). The critical aggregation concentrations (CACs) of both Peptide-PMA and Peptide-PMAS micelles are measured by fluorescence spectroscopy.
Instrument
J-815
Keywords
Circular dichroism, Secondary structure, Polymers, Biochemistry