Differential polarization microscopy: Theory and applications

Abstract

In Differential Polarization Microscopy two images of an object obtained usina orthogonal incident polarizations are subtracted from each other. The resulting difference image can display both magnitude and sign whose values will vary according to location in the image and the value of the local optical anisotropy of the object.Thus, Linear Dichroism and Circular Dichroism images of an object can be obtained.a) In-situ studies of the polymerization of Hb S in red blood sickle cells.-Mutant hemoglobin Hb S, present in sickle cell anemia, tends to aggregate at low pressures of oxygen forming polymers. Furthermore various polymers can align side by side. Using differential polarization image we can detect the angle of alignment and amount of polymerized HbS inside a red blood cell. We have also developed a supra-vital method for following the reversible process of polymerization and alignment inside a red blood cell, as a function of the oxygen pressure.