One-step covalent microcontact printing approach to produce patterns of lactate oxidase.

A comparative study of three different strategies to pattern lactate oxidase (LOx) onto bare gold substrates by microcontact printing (muCP) is presented. The quality of the resulting patterns in terms of homogeneity, compactness and stability has been evaluated by atomic force microscopy in both air and aqueous conditions. The following approaches have been tested: (i) LOx was directly stamped to a bare gold surface; (ii) LOx was previously covalently bonded to a thiolated molecule, dithiodipropionic acid di(N-succinimidyl ester) (DTSP), and this conjugate (LOx/DTSP) was transferred from an elastomeric stamp to a bare gold substrate; (iii) formation of a LOx/DTSP micropattern on a bare gold surface (as described in approach ii) was followed by exposure to a solution containing hexadecylmercaptane (HDM). In all cases, the catalytic activity of the final LOx patterns has been assessed by electrochemical measurements. From comparison of the three strategies, it can be concluded that the third one gives rise to LOx patterns that present a high stability and compactness, also offering the advantage of reducing the number of microcontact printing steps to one.