Detection of the sickle hemoglobin allele using a surface plasmon resonance based biosensor

Sickle Cell Disease (SCD) is a monogenic hereditary blood disorder caused by a single point mutation (β^S) in the β globin gene resulting in an abnormal hemoglobin (HbS) that can polymerize within the erythrocytes, inducing their characteristic sickle shape. This causes hemolytic anemia and occlusive vessels for the most severe clinical status. Molecular analysis is crucial for fast and precise diagnosis of different forms of SCD, and, on the basis of underlying genotype, for supporting the most appropriate treatment options. In this context, we describe a simple and reproducible protocol for the molecular identification of the β^S mutation based on surface plasmon resonance (SPR) using the Biacore™ X100 affinity biosensor. This technology has already demonstrated its diagnostic suitability for the identification of point mutations responsible for genetic diseases such as cystic fibrosis and β thalassemia, using a protocol based on immobilization of PCR products on the sensor chip. On the contrary, in this work we applied a SPR strategy based on an innovative interaction format, recently developed in our group also for β thalassemia mutations. In particular, we correctly detected the β^S mutation responsible for SCD, both in homozygous and heterozygous states, after hybridization of two oligonucleotide probes (normal and mutated) for the β^S mutation, immobilized on sensor chip, with unbalanced PCR products obtained from 53 genomic DNAs carrying different β^S allele combinations.