The dielectrophoresis of blood platelets as affected by hemophilic traits

We find that there are moderate differences in the electrical polarizabilities of normal and various hemophilic canine blood platelets. The technique of dielectrophoresis, using the effect of nonuniform fields on neutral bodies, was used to perform rapid assays of the platelets. At present the dielectrophoretic test can only distinguish reliably between relatively large groups of animals on a statistical basis. The present technique shows a unique ability however, to distinguish even between normal canine platelets and the transmitter female canine platelets. In studies of the effects of various chemical agents upon the dielectrophoresis of platelets, inhibitors such as NaF, sodium iodacetate, NaCN, and NaN₃ had marked effects at low concentration. Ions such as Na⁺ K⁺, Mg⁺⁺, and La⁺⁺⁺, as well as NO₃ ⁻, SO₄ ⁼, and mellitic ion had lesser effects. In some cases the presence of trace quantities of the chemical agent “stabilizes” the cellular dielectrophoretic response, enabling the platelet to continue to be attracted by the nonuniform field for longer than usual. The CN⁻ and F⁻ ions appear to do this. This may have useful application. From the shape of the frequency spectrum of the dielectrophoretic response we suggest that the peaks at about 0.1 to 10 MHz imply a Maxwell-Wagner type of response, typical of an interface between bulk regions of differing conductivity, as at the cell boundary. From a lack of low frequency response, we suggest that the platelet interface with the surrounding aqueous medium must be singularly free of ionic double layers — or at least that the ionic double layers present must be of unusually low charge density. The technique of dielectrophoresis has been used in comparative study of canine blood platelets, from (1) normal dogs, (2) female dogs that transmit Factor VIII deficiency to their offspring, (3) male dogs with Factor VIII deficiency, and (4) female dogs with Factor VIII deficiency. The study showed that differences exist between the 4 groups of dogs in the average dielectrophoretic responses at 1 MHz. The effect of several chemical agents, i.e., NaCN and NaF on normal canine platelets was to effectively stabilize the platelets against deteriorationin vitro.