Effect of sodium dodecylbenzene sulfonate on mass and volume of collagen

Changes in mass and volume of collagen on interaction with sodium dodecylbe nzene sulfonate (SDBS) were studied using prepared fibres of beef Achilles tendons at two pH levels (pH = 3, pH = 6,5 respectively) and various levels of ionic strenghts; (adding NaCl). Degree of swelling (a) was used for the description of these changes. Both type of above changes had the same tend ences and their values vere practically equal. At pH = 3 under low ionic st renghts and in absence of SDBS a high swelling was attained. An addition of SDBS to reaction mixture led to vigorous deswelling. A drop in a occured w ithin a very narrow interval of SDBS equilibrium concentrations and/or equi librium amount of bound SDBS. This narrow interval of bound SDBS correspond ed to lag phase of SDBS-collagen isotherm. With higher ionic strenghts a wa s independent on the equlibrium amounts of SDBS. Under isoelectric conditio ns (:pH = 6.5) changes of a were markedly smaller than in acid region. The mass changes of collagen on reaction with SDBS were reversible. Repeating s orption and desorption of SDBS from collagen led to the same values of a as on simple sorptions. Fibres of collagen crosslinked by Cr(III) (0.56% Cr2O 3) did not swell on reaction of SDBS.