The issue of controlling antibiotic residues poses a severe threat that the society urgently needs to address. An effective way to enhance antibiotic control would be implementing a rapid, sensitive, and cost-effective detection method [1]. In this work, we report the development of a novel system based on integrating localized surface plasmon resonance (LSPR) and quartz crystal microbalance (QCM) methods in a fluidic chamber. We performed penicillin (PEN) detection utilizing DNA thiolated aptamers as receptors chemisorbed on gold nanoparticles (AuNPs, diameter 80 nm) immobilized on quartz crystal (Fig. 1A). The sensing area was incubated with PEN in a 1-100 µM concentration range. This resulted in a decrease in the resonant frequency of QCM, as well as changes in the LSPR signal observed as a shift of the extension peak (Fig. 1B). Subsequently, the sensor specificity was determined using oxytetracycline, kanamycin, and ampicillin. The results demonstrate that the sensor specifically binds PEN. Although we have not reached high detection limits in the nM range, this work shows the preliminary results of a correlative, and real-time detection system for biosensing. Furthermore, the advantage of a simultaneous measurement is that when a detection is made, it can be confirmed by double measurement. The sensitivity of the two techniques can also be compared. With LSPR, the wavelength shift was proportional to the penicillin concentration in the range 0.01-0.03 nm, with a noise of 0.01 nm, while with QCM, the resonance shift was 6-21 Hz, considering a noise of 1-2 Hz.

References

[1] Laich, F.; Fierro, F.; Martín, J.F. Applied and Environmental Microbiology. 2002, 68, 1211-9. doi: 10.1128/AEM.68.3.1211-1219.2002.

Acknowledgments

This work was funded under the European Union’s Horizon 2020 research and innovation program through the Marie Skłodowska-Curie grant agreement No. 101007299 (T.H.), the Science Agency VEGA, project No. 1/0445/23 (T.H.) and by DAAD PPP project (T.H. and W.F.).