Effect of lanthanum ion on platelet electrophoretic mobility

Area of Science:

• Biophysics
• Hematology
• Surface Chemistry

Background:

• Human platelets are critical for hemostasis and thrombosis.
• Electrophoretic mobility is a key indicator of cell surface charge.
• Lanthanum (La3+) is a trivalent cation with known interactions with biological surfaces.

Purpose of the Study:

• To investigate the effect of trivalent La3+ ions on the electrophoretic mobility of human platelets.
• To determine the pH-dependent interaction of La3+ with platelet surface charges.
• To elucidate the binding mechanism of La3+ to platelet surfaces.

Main Methods:

• Washed human platelets were subjected to electrophoretic mobility measurements.
• Experiments were conducted in a 0.145 M sodium chloride solution across a range of pH values.
• Varying concentrations of La3+ were introduced to assess their impact on mobility.

Main Results:

• Human platelets exhibited a baseline electrophoretic mobility of -0.84 +/- 0.06 μm/sec/V/cm at pH 7.2, with an isoelectric point near pH 3.4.
• La3+ ions, at concentrations similar to physiological calcium (Ca2+), reversed the sign of platelet electrophoretic mobility at pH 5.5 and pH 4.0.
• The effect of La3+ on mobility was minimal at pH 3.0 and pH 2.0.

Conclusions:

• Trivalent La3+ ions significantly influence human platelet surface charge.
• The interaction is pH-dependent, suggesting specific binding sites.
• La3+ is presumed to bind to phosphate groups on the platelet surface, altering their net charge.