Methods of measuring barrier formation

A method of measuring formation of a barrier to restrict or reduce movement of an electroactive species, the method comprising:

• providing an electrochemical cell having a working electrode and a counter electrode spaced from the working electrode;
• providing a subject component, a testing component and at least one electroactive species within the cell, the subject and testing components being intended to cause the formation of a barrier by an agglutination reaction to restrict or reduce movement of an electroactive species;
• applying a DC potential to the electrochemical cell between the working electrode and the counter electrode sufficient to produce a current related to the rate of mass transport of the electroactive species being measured to the working electrode;
• and
• measuring the current at the working electrode to obtain a measure of the formation of the barrier to restrict or reduce movement of the electroactive species.