XXII Congresso Nazionale della Società Chimica Italiana
FIRENZE, 10-15 SETTEMBRE 2006
Development of a DNA-based piezoelectric biosensor for
the simultaneous detection and genotyping of high risk
Human Papilloma Virus strains
D. Dell’Atti, M. Minunni, S. Tombelli, M. Mascini
Università degli Studi di Firenze, Dipartimento di Chimica
A. Cavazzana, M. Zavaglia, G. Bevilacqua
Università degli Studi di Pisa, Dipartimento di Oncologia, dei trapianti
e delle nuove tecnologie in medicina
DNA Based Biosensors
Synthesis of a DNA fragment (probe)
containing the sequence of interest
Immobilisation of the probe onto the
solid support of the sensor
(thiol/dextran/streptavidin/biotinylated probe)
Extraction of the DNA from the real
sample (blood, water, food) and
amplification of the sequence of interest
Denaturation of the amplified fragment to
obtain a single-stranded DNA
Hybridisation of the obtained ssDNA with
the immobilised probe
Changes in the physicochemical parameters of the layer formed on the transducer
Instrumentation
• 9.5 MHz AT-Cut quartz crystal (14mm)
• Gold evaporated (42.6mm2 area) on both sides
Crystal Manufactoring (USA)
Methacrylate cell
QCMagic (ElbaTech, Marciana, Italy)
Immobilisation protocol
11-mercaptoundecanol
HO
HS
HO
HS
HO
HO
HS
HS
HO
HS
HO
HS
HO
HS
HO
HS
dextran
HO
HO
HO
HO
HO
HO
HO
HO
HS
HS
HS
HS
HS
HS
HS
HS
gold
streptavidin
HO
HO
HO
HO
HO
HO
HO
HO
HO
HO
HO
HO
HO
HO
HO
HO
HS
HS
HS
HS
HS
HS
HS
HS
HS
HS
HS
HS
HS
HS
HS
HS
biotinylated probe
Biosensor signals
9475800
9475600
H2O
Frequency (Hz)
9475400
Probe immobilisation
activation
9475200
streptavidin
9475000
buffer
9474800
ethanolamine
9474600
buffer
probe
9474400
9474200
9474000
0
500
1000
9474600
2000
2500
Number acquisition
9474580
A.
B.
C.
D.
Hybridisation cycles
9474560
Frequency (Hz)
1500
9474540
9474520
9474500
9474480
A
D
A
Analytical datum
is ∆F (Fc-Fa)
B
C
9474460
9474440
9474420
9474400
0
200
400
Hybridisation buffer
Target ( 10 min)
Hybridisation buffer
Regenerating
solution
HCl 1mM ( 2*30”)
600
800
Number Acquisition
1000
1200
1400