title: Alkaline treatments to render starch-based biodegradable polymers self-mineralizable.
abstract: The present research aims to develop a new route for surface functionalization of biodegradable polymers. The method is based on a wet chemistry modification, resulting in etching and/or hydrolysis in order to increase the amount of polar groups, such as hydroxyl (--OH) and carboxylic (--COOH) groups on the surface of the polymer. The polymer used as substrate was a corn starch-ethylene vinyl alcohol biodegradable blend (SEVA-C). For that purpose it was used in two different types of activation: (a) calcium hydroxide solution [Ca(OH)(2)] and (b) sodium hydroxide solution (NaOH). These treatments lead to the formation carboxylic acid-rich SEVA-C surfaces. Then, the samples were soaked in simulated body fluid (SBF) for different time periods of time until 7 days. After 1 day in SBF, the surface of SEVA-C was fully covered with spherulite particles. As the soaking time increased, the particles increased and coalesced, leading to the formation of a dense and uniform layer. Furthermore, thin-film X-ray diffraction confirms that the layer formed on the surface of the polymer was an apatite-like layer. These results suggest that this rather simple treatment is a good method for surface functionalization and subsequent mineral nucleation and growth on biodegradable polymeric surfaces to be used for bone-related applications.
authors.affiliation: 3Bs Research Group, Department of Polymer Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal. belinha@dep.uminho.pt
authors.forename: I B
authors.initials: IB
authors.lastname: Leonor
authors.forename: H-M
authors.initials: HM
authors.lastname: Kim
authors.forename: F
authors.initials: F
authors.lastname: Balas
authors.forename: M
authors.initials: M
authors.lastname: Kawashita
authors.forename: R L
authors.initials: RL
authors.lastname: Reis
authors.forename: T
authors.initials: T
authors.lastname: Kokubo
authors.forename: T
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000388:Air; D000687:Amylopectin / Q000737:chemistry; D000688:Amylose / Q000737:chemistry; D001672:Biocompatible Materials / Q000378:metabolism*; D001826:Body Fluids; D002126:Calcium Hydroxide / Q000737:chemistry / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism*; D011145:Polyvinyls / Q000378:metabolism*; D012972:Sodium Hydroxide / Q000737:chemistry / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared; D013057:Spectrum Analysis; D013213:Starch / Q000378:metabolism*; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D008903:Minerals; D011108:Polymers; D011145:Polyvinyls; C439612:corn starch-co-ethylene vinyl alcohol blend; D012972:Sodium Hydroxide; D013213:Starch; D000688:Amylose; D000687:Amylopectin; D002126:Calcium Hydroxide