title: Engineering preliminaries to obtain reproducible mixtures of atelocollagen and polysaccharides.
abstract: The critical stage in producing blends of biomacromolecules consists in the mixing of component solutions to generate homogenous diluted colloidal systems. Simple experimental investigations allow the establishment of the design rules of recipes and the procedures for preparing homogenous and compositionally reproducible mixtures. Starting from purified solutions of atelocollagen, hyaluronan and native gellan, having as low as possible inorganic salts content, initial binary and ternary mixtures can be prepared up to a total dry matter content of 0.150 g/dL, in no co-precipitating conditions. Two pH manipulation ways are feasible for homogenous mixing: (i) unbuffered prior correction at pH 5.5, and (ii) "rigid" buffering at pH 9.0, using organic species. Atelocollagen including co-precipitates can be obtained in the presence of one or both polysaccharides, preferably in pH domains far from the isoelectric point of scleroprotein. A critical behavior has been observed in mixtures containing gellan, due to its macromolecular dissimilarities compared with atelocollagen. In optimal binary mixtures, the coordinates of threshold points on the phase diagrams are 0.028% w/w atelocollagen/0.025% w/w hyaluronan, and 0.022% w/w atelocollagen/0.020% w/w gellan. Uni- or bi-phasic ternary systems having equilibrated ratios of co-precipitated components can be prepared starting from initial mixtures containing up to 0.032 g/dL atelocollagen, associated with, for example, 0.040 g/dL hyaluronan and 0.008 g/dL gellan, following the first pH manipulation way.
authors.affiliation: Department of Natural and Synthetic Polymers, "Gheorghe Asachi" Technical University of Iaşi, 73 Prof. Dimitrie Mangeron Str., 700050, Iaşi, Romania.
authors.forename: Cristina-Mihaela
authors.initials: CM
authors.lastname: Lefter
authors.forename: Stelian Sergiu
authors.initials: SS
authors.lastname: Maier
authors.forename: Vasilica
authors.initials: V
authors.lastname: Maier
authors.forename: Marcel
authors.initials: M
authors.lastname: Popa
authors.forename: Jacques
authors.initials: J
authors.lastname: Desbrieres
mesh_terms: D002021:Buffers; D003094:Collagen / Q000138:chemical synthesis* / Q000737:chemistry; D006820:Hyaluronic Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009391:Nephelometry and Turbidimetry; D044367:Phase Transition; D011134:Polysaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D015203:Reproducibility of Results; D012996:Solutions; D023822:Tissue Engineering / Q000379:methods*; D014783:Viscosity
chemical_list: D002021:Buffers; D011134:Polysaccharides; D011135:Polysaccharides, Bacterial; D012996:Solutions; C059821:atelocollagen; C048288:gellan gum; D006820:Hyaluronic Acid; D003094:Collagen