Studies Of Rheological Properties Of Ca-Alginate Hydrogel Micropheres Suspension And Its Effect Factors

Blood rheology test method standardization has been a hot spot in clinical research.To ensure the truth and reliability of viscometer laboratory results, whole bloodviscosity detection needs standardized quality control overall process, including internalquality control（IQC）and external quality assurance（EQA）. Especially the research andapplication of clinical blood viscosity quality control substance is essential. The qualityof whole blood quality control substance and the use of it properly or not will directlyinfluence the final test results and test scores. Now studies of whole blood qualitycontrol substance is relatively rare, both at home and abroad. Although some newguidelines of laboratory techniques further standardized hemorheological test methods,the current situation that whole blood viscosity quality control level is low still has nofundamental changes. Only by finding a stable standard substance can preferably reflectnon-Newtonian fluid properties on whole blood, can we achieve the real laboratoryviscosity detection quality control.Based on size, shape of red blood cells, and Hematocrit （Hct is approximately45vol%） consideration, taking a suspension made by hydrogel microspheres suspendedin a liquid medium as research object, this airticle mainly discussed rheologicalproperties of Ca-alginate hydrogel micropheres suspension and its effect factors. Inexperiments ultrasound emulsion polymerization was used to produce Ca-alginatehydrogel microspheres（C1）and Ca-alginate hydrogel microspheres containinghemoglobin（C2）. Atomic force microscope（AFM） was applied to detect force-distancecurves for these microspheres. Some mechanical informations such as stiffness andviscoelasticity were obtained. After statistics analysis, the measured Young’s moduluswere4.01±0.57kPa and1.33±0.70kPa, for C1and C2respectively. Then this two typesof microspheres were suspended respectively with0.9wt%sodium chloride solutions toobtain suspension samples with50%microsphere volumns. Viscometer FASCO-3010was applied to detect shear viscosity of the samples at shear rate range from1to200s^-1,and viscosity changes at different pH. In addition, Viscometer FASCO-3010andLG-R-80c were respectively used to test storage stability of Ca-alginate hydrogelmicrosphere suspension for5weeks. Through statistics analysis, the CV of viscosityresults corresponding with two instruments were7.3%to13.8%and9.7%to14.2%.These results demonstrated that microsphere elastic deformation ability is the main factor to influence rheological properties of suspension samples. Increasing of thisability can effectively reduce shear viscosity of these samples at medium or high shearrate. At the same time, pH also has some effects on rheological properties of suspensionsamples. With rising pH value, shear viscosity of suspension samples at low shearrate(1s^-1～10s^-1) has a significant growth. The real reason for this result may be thevariation of pH changed microspheres aggregation, and then affected viscosity at lowshear rate. Although some differences existed among the results from the samples in thesame batch by two types of viscometers, both of which has represented a shear-thinningeffect like whole blood, having a potential of being widely applied in calibratingdifferent blood viscometers.