Quartz crystal microbalance-based biosensor for the detection of α-thalassemia 1 (SEA deletion).
BACKGROUND
DNA piezoelectric biosensors have become a promising tool in molecular medicine since they do not require any label or staining. Here, a DNA piezoelectric biosensor based on a quartz crystal microbalance (QCM) was created to identify abnormal genes causing α-thalassemia 1 (SEA deletion).


METHODS
The functionalized gold electrode of the quartz crystal was coated with avidin and the biotinylated DNA probe was attached. The target gene causing α-thalassemia 1 was amplified and hybridized with the immobilized probe. DNA hybridization was indicated by changes in the quartz resonance frequencies. Diagnostic ability of the new α-thalassemia 1 biosensor was validated using both known and unknown blood samples. Specificity was tested using samples of β-thalassemia and α-thalassemia 2. Stability of the sensor was also evaluated.


RESULTS
The new biosensor could clearly identify α-thalassemia 1 (SEA deletion), both carrier and disease states, from the normal genotype. Identification accuracy was compatible to the standard gel electrophoresis. It was specific only to α-thalassemia 1 since no cross reaction was found with β-thalassemia and α-thalassemia 2. The sensor could be kept at room temperature up to 6 months with consistent identification accuracy.


CONCLUSIONS
The label free QCM based biosensor was successfully developed to diagnose an abnormal human globin gene causing α-thalassemia 1 (SEA deletion). Its accuracy, specificity and sensitivity were comparable to the standard method. Its stable diagnostic potency up to 6 months implied its field application in thalassemic control program.
Chomean
Sirinart
S
Faculty of Medical Technology, Department of Clinical Microscopy, Mahidol University, Nakhon Pathom, Thailand.
Potipitak
Tiparat
T
Promptmas
Chamras
C
Ittarat
Wanida
W
D001360:Avidin / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000378:metabolism; D019921:Biotinylation; D004247:DNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D017931:DNA Primers / Q000235:genetics; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006801:Humans; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes / Q000737:chemistry / Q000235:genetics; D016133:Polymerase Chain Reaction; D058525:Quartz Crystal Microbalance Techniques / Q000379:methods*; D015203:Reproducibility of Results; D017085:alpha-Thalassemia / Q000175:diagnosis* / Q000235:genetics
D017931:DNA Primers; D015345:Oligonucleotide Probes; D001360:Avidin; D001710:Biotin; D006046:Gold; D004247:DNA