Multipurpose Love acoustic wave immunosensor for bacteria, virus or proteins detection

Acoustic Wave-Based Detection in Bioanalytical Chemistry: Competition for Surface Plasmon Resonance?

“…This sensitivity enhancement resides fundamentally in the fact that higher operating frequencies are involved (typically, 100-500 MHz) and that the AW restrictively propagates in a guiding layer on the surface of a higher-resonating (greater f o ), thinner substrate. Recently, a multipurpose Love-wave immunosensor showed its versatility through the detection of bacteria, virus or proteins and exhibited promising performance, with a sensitivity for proteins reaching 4 ng=mm 2 (Moll et al 2008). The Love-wave device is an example of a surface-launched AW sensor.…”

“…It should be noted that, at least for the liquid phase, almost all AW measurements of whatever kind have been assumed, incorrectly, to constitute simple mass detection à la Sauerbrey (1959). In contrast, recent times have seen both more positive statements regarding advances in TSM- (Cooper and Singleton 2007) and surface acoustic wave-based (SAW)-based devices (Moll et al 2008) and critical evaluation of SPR technology (Gronewold 2007).…”

QCM Technology in Biosensors

“…Experimental and theoretical techniques to evaluate mass sensitivity of Love Wave sensors are reported in literature (Francis et al, 2004;Harding, 2001;Wang et al, 1994). Kalantar and coworkers reported a sensitivity of 95 Hz cm 2 ng -1 for a 100MHz Love mode sensor, which is much better than the values reported for QCM technology (Kalatar et al, 2003); however, Moll and coworkers reported a LOD for a Love sensor of 400 ng cm -2 , this reveals once again that an increase in the sensitivity does not mean, necessarily, an increase in the LOD (Moll et al, 2008). Moreover, in spite of the initial advantage of the guiding layer for isolating the IDTs, in real practice the capacitive coupling between the IDTs due to the higher permittivity of the liquid makes necessary to avoid the contact of the liquid with the guiding layer just over IDTs, at the same time that it is necessary to allow the contact of the central area between the IDTs with the liquid medium.…”

“…In addition, the wave guide layer in the Love mode biosensor could, in principle, also protect and insulate the IDT from the liquid media which might otherwise be detrimental to the electrode. Therefore, they are frequently utilized to perform bio-sensing in liquid conditions (Lindner, 2008;Jacoby & Vellekoop, 1997;Bisoffi et al, 2008;Andrä et al, 2008;Moll et al, 2007Moll et al, , 2008Branch & Brozik, 2004;Tamarin et al, 2003;Howe & Harding, 2000), arising as the most promising SGAW device for this purpose due to its high mass sensitivity and electrode isolation characteristics from liquid media (Rocha-Gaso et al, 2009;Francis et al, 2005). The mass sensitivity of LW sensors can be evaluated by different techniques based on incremental modifications of the surface density on the sensing area of the device (Francis et al, 2004).…”

Microbiological Detectors for Food Safety Applications

“…E. coli detection using SAW biosensors have been reported in the literature by multiple authors [40][41][42][43]. The biosensors have used antibodies as the biological sensing element with sensitivities ranging from 10 6 cells/ml to 0.4 cells/μl.…”