Micro-cantilevers for optical sensing of biogenic amines

Abstract

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

Optimizing Piezoelectric Cantilever Design for Electronic Nose Applications

“…The resonance frequency found to reduce linearly by 3.8 kHz per mg added. Then the cantilevers were functionalized with a cadaverine binder, as described in a previous work [23][24][25] and exposed to tuna pieces [27]. Figure 12 shows the shift in resonance frequency when exposed to tuna pieces with different ages.…”

“…The piezoelectric cantilever beam voltage output and the resonance frequency can be optimized through modeling techniques for improved performance [22]. We have previously conducted studies about cadaverine binding to functionalised cantilever surfaces [23][24][25].…”

Meat and fish freshness evaluation by functionalized cantilever-based biosensors

“…The cantilever was exposed to chicken (stored at 5°C after each measurement) for 5 consecutive days, and the changes on cantilever resonance frequency due to mass increase (cadaverine binding) was measured daily, by optical beam reflection. The mass of bound cadaverine can be calculated by the following equation [13]:…”

“…Silicon nitride cantilevers containing piezoelectric layers -[Si-Oxide(1µm)/Poly-Si(14µm)/Si-Oxide(1µm); AlN(50 nm)/Mo(100 nm); AlN(2 µm)/Mo(150 nm); Si-Nitride (1 µm);] (width = 1000 µm, length = 1500 µm) were functionalized by drop-casting, based on the previous functionalization results. The resonance frequencies of the commercial cantilevers before and after cadaverine exposure were measured by optical beam deflection, by using an optical sensing system where a laser beam is reflected by the cantilever and detected by a photodiode, as described in [13]. The increase in mass on the cantilever due to cadaverine binding was calculated based on the changes of resonance frequency and on the cantilever parameters.…”

“…Other methods applied for biogenic amines determination are thin layer, gas and high-performance liquid chromatography [12], which give a good precision, but are very large and time consuming. We have performed investigations on nano-functionalization chemistry for sensory surfaces which are high selectively binding to cadaverine [13][14]. This functionalization layer is applied into micro-cantilever sensors.…”