An rGO-FET-based Aptasensor for Quantification of the Clinically Relevant Pathogenic Bacterium Streptococcus agalactiae

Description

Streptococcus agalactiae (group B Streptococcus, GBS) remains a major cause of maternal and neonatal morbidity and mortality and is particularly associated with early-onset neonatal sepsis following vertical transmission. Approximately 11-35% of pregnant women are colonized with GBS and the pathogen is associated with substantial numbers of fetal and infant deaths, stillbirths and preterm births worldwide. Current culture-based diagnostics require up to several days, while molecular methods depend on specialized equipment and trained personnel, highlighting the need for rapid and accessible detection strategies. In this study, S. agalactiae-specific DNA aptamers were generated by six rounds of whole FluCell-SELEX combined with next-generation sequencing and subsequently validated their applicability in electrical biosensing using a reduced graphene oxide field-effect transistor (rGO-FET) plattform. Four individual aptamer candidates showed pronounced target preference and low-nanomolar apparent dissociation constants. Following sensor integration, the individual aptamer Anti-SA-4 exhibited the most pronounced and reproducible concentration-dependent electrical response, with a calculated analytical limit of detection of approximately 3.7 × 10¹ cells mL⁻¹ and statistically significant discrimination at 10 cells mL⁻¹. These findings identify Anti-SA-4 as a promising recognition element for rapid, sensitive and label-free GBS detection and support the further development of accessible, user-friendly biosensor platforms for maternal screening and prevention of severe neonatal outcomes.

Institutions

• Universität Ulm

  Baden-Wurttemberg, Ulm

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