The longer chain tends to substitute the shorter chain due the thermodynamically favourable van der Waals interactions between the longer hydrocarbon chains. Symmetrical disulfides, such as dithiobis(succinimidyl propionate), DTSP, can also be employed for the attachment of proteins to an electrode surface. This is an attractive surface modification due to the N-hydroxysuccinimide ester terminal groups, which facilitate binding to a biorecognition element without an intermediate step or