QCM Genosensor for Detection of Golden Mosaic-Resistant Transgenic Common Beans in Non-Amplified Samples

A quartz crystal microbalance-based biosensor for the specific detection of the first transgenic
common bean (Phaseolus vulgaris L.) cultivar (BRS FC401 RMD) with resistance to bean golden mosaic
virus (BGMV) was developed. The immobilization chemistry relies on the strong bond between the
thiolated probe and the gold electrode surface. The probe sequence is internal to a region of the
BGMV rep gene that was introduced into the common bean genome. The sensor's analytical
performance was determined using synthetic oligonucleotides. Real samples of transgenic and wild-
type bean seeds were also tested. Sample pretreatment consisted only of enzymatic fragmentation,
followed by a thermal denaturation step combined with blocking oligonucleotides. Different
biosensor regeneration approaches were studied. Immobilization showed good reproducibility
(CV% of 5.8%). The biosensor proved specific for both synthetic oligonucleotides and non-amplified
genomic DNA. A linear detection range of 0–1.4 ng/µL was observed, with a detection limit of 0.18
ng/µL. Three sequential detections were performed without loss of surface activity. The results
demonstrate the biosensor's potential for direct, real-time, label-free detection of DNA samples for
field screening of transgenic common bean cultivars.