Evaluating viscoelastic properties and membrane electrical charges of red blood cells with optical tweezers and cationic quantum dots - applications to beta-thalassemia intermedia hemoglobinopathy

摘要

Biomechanical and electrical properties are important to the performance and survival of red blood cells (RBCs) in the microcirculation. This study proposed and explored methodologies based on optical tweezers and cationic quantum dots (QDs) as biophotonic tools to characterize, in a complementary way, viscoelastic properties and membrane electrical charges of RBCs. The methodologies were applied to normal (HbA) and beta-thalassemia intermedia (Hb beta) RBCs. The beta-thalassemia intermedia disease is a hereditary hemoglobinopathy characterized by a reduction (or absence) of beta-globin chains, which leads to alpha-globin chains precipitation. The apparent elasticity (mu) and membrane viscosity (eta(m)) of RBCs captured by optical tweezers were obtained in just a single experiment. Besides, the membrane electrical charges were evaluated by flow cytometry, exploring electrostatic interactions between cationic QDs, stabilized with cysteamine, with the negatively charged RBC surfaces. Results showed that Hb beta RBCs are less elastic, have a higher eta(m), and presented a reduction in membrane electrical charges, when compared to HbA RBCs. Moreover, the methodologies based on optical tweezers and QDs, here proposed, showed to be capable of providing a deeper and integrated comprehension on RBC rheological and electrical changes, resulting from diverse biological conditions, such as the beta-thalassemia intermedia hemoglobinopathy.