Chronopotentiometric Stripping Analysis of Gelatinase B, Collagen and Their Interaction

Matrix metalloproteinases (MMP) belong to a group of zinc-dependent proteins that play a central role in the breakdown of extracellular matrices. Collagen, elastin, gelatin and casein are the main components of extracellular matrix cleaved by MMP This paper aims to analyze the interaction between gelatinase B (MMP-9) and collagen using chronopotentiometric stripping analysis with adsorptive transfer stripping technique (AdTS CPSA). Under optimized experimental conditions (time accumulation of 90 s, supporting electrolyte 0.2 M acetate buffer pH 5, stripping current.1 mu A), the detection limit (3 signal/noise) for MMP-9 was estimated as being 100 pM. The interaction between MMP-9 and collagen was studied according to the following scheme: i) HMDE surface was renewed. ii) Renewed surface of HMDE collagen (1 mu g/mL) was accumulated for 90 s under open circuit. iii) The electrode was rinsed in ACS grade water and immersed in 5 mu L drop of MMP-9. iv) The interaction between MMP-9 with collagen took place at open circuit. v) The electrode was then rinsed in ACS grade water. vi) The rinsed electrode was transferred into an electrochemical cell and measured in acetate buffer (pH 5). The CPSA signal of collagen after its interaction with MMP-9 increased more than 30% compared to that of only collagen. This increase in signal is likely due to the cleavage of collagen by MMP-9, hence its easy access to the electrode's surface.