title: Detection of polymolecular associations in hydrophobized chitosan derivatives using fluorescent probes.
abstract: The microenvironment formed by lauroyl and stearoyl derivatives of chitosan in solution has been studied using two fluorescent probes, pyrene and nabumetone. Existence or not of microdomains formed by polymolecular associations, the inherent hydrophobicity of them in aqueous solution, and the influence of degree of substitution (DS) of derivatives were investigated by emission properties of pyrene and strengthened by the photophysical behavior of nabumetone. Additionally, the ratio between the fluorescence intensities of first (approximately 372 nm) to the third (approximately 384 nm) bands of the emission spectrum of pyrene was used to determine the critical aggregation concentration (CAC). In a previous work, it was already reported the characterization of chitosan derivatives by three spectroscopic techniques ((13)C-NMR, (1)H-NMR and infrared), as well as data on the solubility and swelling-index of them. In addition of that, the new results show that the investigated lauroyl and stearoyl derivatives of chitosan are expected to be potential models for applications in the medical field.
authors.affiliation: Instituto de Pesquisa & Desenvolvimento-IP&D, Universidade do Vale do Paraíba-UNIVAP, Av. Shishima Hifumi 2911, Urbanova, CEP: 12244-000, São José dos Campos, SP, Brazil. mrr@univap.br
authors.forename: Máira R
authors.initials: MR
authors.lastname: Rodrigues
authors.forename: Adriana
authors.initials: A
authors.lastname: Lima
authors.forename: Lúcia
authors.initials: L
authors.lastname: Codognoto
authors.forename: Antonio Balbin
authors.initials: AB
authors.lastname: Villaverde
authors.forename: Marcos Tadeu
authors.initials: MT
authors.lastname: Tavares Pacheco
authors.forename: Hueder P
authors.initials: HP
authors.lastname: Moisés de Oliveira
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D002074:Butanones / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D000077430:Nabumetone; D011721:Pyrenes / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002074:Butanones; D005456:Fluorescent Dyes; D011721:Pyrenes; D048271:Chitosan; C030984:pyrene; D000077430:Nabumetone