Towards a Multi-Enzyme Capacitive Field-Effect Biosensor by Comparative Study of Drop-Coating and Nano-Spotting Technique

Sensors, vol. 20, pp. 4924

Abstract

Multi-enzyme immobilization onto a capacitive field-effect biosensor by nano-spotting technique is presented. The nano-spotting technique allows to immobilize different enzymes simultaneously on the sensor surface with high spatial resolution without additional photolithographical patterning. The amount of applied enzymatic cocktail on the sensor surface can be tailored. Capacitive electrolyte-insulator-semiconductor (EIS) field-effect sensors with Ta2O5 as pH-sensitive transducer layer have been chosen to immobilize the three different (pL droplets) enzymes penicillinase, urease, and glucose oxidase. Nano-spotting immobilization is compared to conventional drop-coating method by defining different geometrical layouts on the sensor surface (fully, half-, and quarter-spotted). The drop diameter is varying between 84 µm and 102 µm, depending on the number of applied drops (1 to 4) per spot. For multi-analyte detection, penicillinase and urease are simultaneously nano-spotted on the EIS sensor. Sensor characterization was performed by C/V (capacitance/voltage) and ConCap (constant capacitance) measurements. Average penicillin, glucose, and urea sensitivities for the spotted enzymes were 81.7 mV/dec, 40.5 mV/dec, and 68.9 mV/dec, respectively.

Authors 4

1. Denise Molinnus Aachen Institute of Nano- and Biotechnologies (INB)

   FH Aachen

   Affiliation as printed

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, 52428 Jülich, Germany

2. Stefan Beging Aachen Institute of Nano- and Biotechnologies (INB)

   FH Aachen

   Affiliation as printed

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, 52428 Jülich, Germany

3. Carsten Lowis Aachen Institute of Nano- and Biotechnologies (INB)

   FH Aachen

   Affiliation as printed

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, 52428 Jülich, Germany

4. Michael Josef Schöning corresponding Aachen Institute of Nano- and Biotechnologies (INB)

   Forschungszentrum Jülich · FH Aachen

   Affiliation as printed

   Institute of Biological Information Processing (IBI-3), Research Center Jülich, 52425 Jülich, Germany

   Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, 52428 Jülich, Germany