THERMOREVERSIBLE GELATION OF A POLYSACCHARIDE WITH IMMUNOLOGICAL ACTIVITY - RHEOLOGY AND DYNAMIC LIGHT-SCATTERING

The beta-1.3/1.6 glucan schizophyllan is known to suppress tumor growt h. Two different schizophyllan samples have been characterized by stat ic and dynamic light scattering in dilute solution of 0.01 M NaOH and dimethyl sulfoxide (DMSO). A thermoreversible, optically transparent g el of schizophyllan was obtained on addition of sorbitol to aqueous so lution, and the gelation process was followed by low amplitude oscilla tory shear and dynamic light scattering (DLS). Power law behavior of s torage modulus G'(omega) and loss modulus G ''(omega) with the exponen t n=0.5 was found at the gel temperature. In the same temperature rang e intensity time correlation functions (TCF) were measured and the ele ctric field TCFs were calculated, taking into account the heterodyne c ontributions. The occurrence of two motions gave evidence for inhomoge neities in the gel. The results of the slow motion from DLS agreed sur prisingly well with those, estimated by oscillatory theology. The visc oelastic properties and the influence of sorbitol and schizophyllan co ncentrations were investigated regarding the pharmaceutical applicatio n in cancer therapy.