Plasmonic Sensor for fetal sex determination: a turning point in non-invasive prenatal diagnosis

Sensors based on plasmonic platforms often operate in complex biological matrices, such as serum or plasma, where multiple analytes may be present. Distinguishing the target analyte, circulating at ultralow concentration from other interfering components with high selectivity, can be a challenging task. To overcome these challenges, in the field of Surface Plasmon Resonance (SPR) technology, researchers work to optimize the design of the biological recognition element, improve sensor surface chemistry, implement signal amplification strategies, and integrate multiplexing format [1]. Here, we will present the challenges and opportunities of our sensing device based on SPR Imaging to achieve low concentration sensitivity in the attomolar range, by adopting an appropriate sensor design relying on functionalized gold nanoparticles [2] and peptide nucleic acid probes (PNA) [3]. By implementing a simplified SPRI assay not requiring the preliminary amplification of the DNA target by PCR, the ultrasensitive detection of male DNA in mixtures of male and female genomic DNAs was achieved. Afterwards, the developed protocol was successfully applied to reveal the Y-chromosome specific sequence (single-gene SRY) in cell-free fetal DNA from plasma of pregnant women even at the earliest gestational age [4]. The development of enhanced performance based on this platform opens the way for the establishment of faster and cost-effective non-invasive prenatal testing, thus establishing an analytical protocol that skips costly, time-consuming, and prone to sample contamination PCR-based approaches. Most importantly, traditional invasive procedures (i.e., amniocentesis or chorionic villus sampling) may be avoided and the small but substantial risk of miscarriage (∼1%) may be eliminated.