TY  - JOUR
A1  - Guha, S.
A1  - Warsinke, Axel
A1  - Tientcheu, Charles Merlin
A1  - Schmalz, K.
A1  - Meliani, C.
A1  - Wenger, Ch.
T1  - Label free sensing of creatinine using a 6 GHz CMOS near-field dielectric immunosensor
JF  - The analyst : the analytical journal of the Royal Society of Chemistry
N2  - In this work we present a CMOS high frequency direct immunosensor operating at 6 GHz (C-band) for label free determination of creatinine. The sensor is fabricated in standard 0.13 mu m SiGe:C BiCMOS process. The report also demonstrates the ability to immobilize creatinine molecules on a Si3N4 passivation layer of the standard BiCMOS/CMOS process, therefore, evading any further need of cumbersome post processing of the fabricated sensor chip. The sensor is based on capacitive detection of the amount of non-creatinine bound antibodies binding to an immobilized creatinine layer on the passivated sensor. The chip bound antibody amount in turn corresponds indirectly to the creatinine concentration used in the incubation phase. The determination of creatinine in the concentration range of 0.88-880 mu M is successfully demonstrated in this work. A sensitivity of 35 MHz/10 fold increase in creatinine concentration (during incubation) at the centre frequency of 6 GHz is gained by the immunosensor. The results are compared with a standard optical measurement technique and the dynamic range and sensitivity is of the order of the established optical indication technique. The C-band immunosensor chip comprising an area of 0.3 mm(2) reduces the sensing area considerably, therefore, requiring a sample volume as low as 2 mu l. The small analyte sample volume and label free approach also reduce the experimental costs in addition to the low fabrication costs offered by the batch fabrication technique of CMOS/BiCMOS process.
Y1  - 2015
U6  - https://doi.org/10.1039/c4an02194k
SN  - 0003-2654
SN  - 1364-5528
VL  - 140
IS  - 9
SP  - 3019
EP  - 3027
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -