Bioelectrocatalytic self-assembled thylakoids for micro-power and sensing applications

Photosynthetic sub-cellular plant structures called thylakoid were immobilized onto a gold electrode surface that had been functionalized by bioelectrocatalytic self-assembled monolayers (bio-SAMs) of cystamine and pyrroloquinoline quinone (PQQ). The goal is to achieve direct transfer of electrons from thylakoids to the electrode via the bio-SAMs to increase the electrical efficiency of MEMS photosynthetic electrochemical cells (mu PECs). The immobilization technique could also be used in MEMS bio-sensing and microbial fuel cell applications. Quartz crystal microbalance with dissipation (QCM-D) was used to characterize the deposition kinetics of cystamine, PQQ, and thylakoids. Using QCM-D, the surface coverage of these three layers was determined to be, respectively, 7.9 x 10(-10) mol/cm(2), 3.3 x 10(-10) mol/cm(2), and 1.5 x 106 thylakoids/cm(2). The cystamine and PQQ monolayers formed within 5 min, while the thylakoid layer required over 1 h. Each layer was shown to be covalently linked to the substrate or layer underneath and thus was able to survive repeated rinsing in water or buffer. (c) 2006 Published by Elsevier B.V.