title: Preparation of self-assembled silk sericin nanoparticles.
abstract: Silk sericin (SS) possessing moisture-retaining property was reacted with activated poly(ethylene glycol) (PEG) to obtain self-assembled SS nanoparticles. The aliphatic and aromatic hydroxyl groups of serine and tyrosine residues as the reaction sites in SS were clarified by amino acid analysis and 1H NMR spectroscopy, respectively. From IR and circular dichroism (CD) measurements, introduction of PEG into SS induced the conformational change from random coil to beta-sheet. DSC thermogram of sericin-PEG conjugate suggests that mutual miscibility between PEG and SS chains was poor. Nanoparticles of sericin-PEG conjugate with sizes measured by dynamic light scattering ranging about 200-400 nm in diameter, were prepared by the diafiltration method. Shape of sericin-PEG conjugate nanoparticles observed by scanning and transmission electron microscopes was spherical. The results suggest that sericin-PEG conjugates are self-associated to form spherical nanoparticles through hydrophobic interaction.
authors.affiliation: School of Biological Resources and Materials Engineering, Seoul National University, Suwon 441-744, South Korea.
authors.forename: Kwang Yong
authors.initials: KY
authors.lastname: Cho
authors.forename: Jae Yu
authors.initials: JY
authors.lastname: Moon
authors.forename: Yong Woo
authors.initials: YW
authors.lastname: Lee
authors.forename: Kwang Gill
authors.initials: KG
authors.lastname: Lee
authors.forename: Joo Hong
authors.initials: JH
authors.lastname: Yeo
authors.forename: Hae Yong
authors.initials: HY
authors.lastname: Kweon
authors.forename: Ki Ho
authors.initials: KH
authors.lastname: Kim
authors.forename: Chong Su
authors.initials: CS
authors.lastname: Cho
mesh_terms: D002942:Circular Dichroism; D007259:Infrared Rays; D019476:Insect Proteins / Q000378:metabolism*; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D010456:Peptides, Cyclic / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D012542:Scattering, Radiation; D047030:Sericins; D012694:Serine / Q000737:chemistry; D047011:Silk; D014443:Tyrosine / Q000737:chemistry
chemical_list: D019476:Insect Proteins; D010456:Peptides, Cyclic; D047030:Sericins; D047011:Silk; D011092:Polyethylene Glycols; D014443:Tyrosine; D012694:Serine