Micro-cantilevers for optical sensing of biogenic amines

This paper discusses the functionalization of micro-cantilevers in order to bind and sense specific biogenic amines related to meat degradation (cadaverine). The micro-cantilevers were functionalized with the composite 1,4,8,11-tetraazacyclotetradecane (cyclam), which is binding to cadaverine molecules in the gas phase. Different functionalization conditions were investigated by immersing gold coated AFM cantilevers in cyclam solutions at different concentrations, for different functionalization times, and for different post-annealing treatments. The optimum morphology for high capture efficiency is found for short functionalization times without post-annealing treatment. Beside qualitative SEM inspection which indicates a significant morphology change for different functionalization parameters, the impact of functionalization morphology on analyte capture efficiency has been studied via micro-cantilever based mass detection. We demonstrate that besides conventional AFM systems a MEMS cantilever in combination with an optical read out is a powerful analytic system which is highly attractive for widespread use in diagnostic applications, with optimized functionalization conditions. The measured sensitivity at 7.7 kHz is 1.84 × 10⁹ Hz/g.