Ivan Rech Politecnico di Milano MICROELECTRONIC PHOTOSENSORS FOR GENETIC DIAGNOSTIC MICROSYSTEMS GE 2003, June 13, 2003 MICROELECTRONIC PHOTOSENSORS FOR

Ivan RechPolitecnico di Milano

MICROELECTRONIC PHOTOSENSORS FOR GENETIC DIAGNOSTIC MICROSYSTEMS GE 2003 , June 13, 2003

MICROELECTRONIC PHOTOSENSORS MICROELECTRONIC PHOTOSENSORS

FOR GENETIC DIAGNOSTIC MICROSYSTEMSFOR GENETIC DIAGNOSTIC MICROSYSTEMS

MICROELECTRONIC PHOTOSENSORS MICROELECTRONIC PHOTOSENSORS

FOR GENETIC DIAGNOSTIC MICROSYSTEMSFOR GENETIC DIAGNOSTIC MICROSYSTEMS

GE 2003

I. Rech; S. Cova; F. Zappa; M. GhioniPolitecnico di Milano - DEI, piazza. Leonardo da Vinci 32, 20133 Milano, Italy

M. Chiari; M. Cretich

CNR - ICRM, via M. Bianco, 20133 Milano



Outline

• Analytical Microsystems and Fluorescence Detection

• SPAD detectors

• Experimental set-up

• Results and prospect



Goal : reduced measurement

operation costs

• higher performance

• lower cost

• higher flexibility

• better automation and control

Genetical analysis

Analisys set-upRequirements :

Small volumes of the reagents



Requirements to Detector

• high QE (Quantum detection Efficiency)

• Low internal noise

• High sensitivity down to Single-Photon detection

• PMT, Photomultiplier Tubes

• CCD, Charge-Coupled Devices

• APD, Avalanche PhotoDiodes

• SPAD, Single-Photon Avalanche Diodes

High-Sensitivity Detectors



• Bias: well ABOVE breakdown

• Geiger-mode: it’s a TRIGGER device!!

• Gain: meaningless ... or “infinite” !!

• Bias: slightly BELOW breakdown

• Linear-mode: it’s an AMPLIFIER

• Gain: limited < 1000

Avalanche PhotoDiode Single-Photon Avalanche Diode

APD SPAD



• Well defined high-field region

• No edge effects

• No microplasmas

• Low generation rate

• Minimum afterpulsing effect

• Low series resistance

• Low cost process

• Low Power dissipation

n

p++p

p

hv

+n

anode cathode

Planar SPAD structure



High QE (Quantum detection Efficiency)



0

5

10

15

20

25

30

35

40

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Sovratensione (V)

Cont

eggi

di B

uio

(cou

nts/

sec.

)

100

150

200

250

300

350

400

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Sovratensione (V)Co

nteg

gi d

i Bui

o (c

ount

s/se

c.)

Active area diameter : 10 Active area diameter : 10 mm Active area diameter : 20 Active area diameter : 20 mm

Low internal noise : Dark Counts



Dark Counts Vs Temperature

0

50

100

150

200

250

300

350

-30 -20 -10 0 10 20

Temperature [C°]

Da

rk C

ou

nts

[c

/s]

+5V

+10V

0

50

100

150

200

250

300

350

-30 -20 -10 0 10 20

Temperature [C°]

Da

rk C

ou

nts

[c

/s]

+5V

+10V

Experimental set-up



Fragment separation

Electropherogram



Counting Module

• Single power supply +5V• Software controlled settings• RS-232 data transmission• Fmax 6.5 MHz• Waveform storage

Politecnico di Milano




SeparationInjection

Sample

Buffer

Waste

Chip Electrophoresis



First Experimental Setup





Current Apparatus : SV3

• Compact and low-cost

• Full automated

• Laser diode for fluorescence excitation

• Controlled chip temperature

• Dual wavelength electropherogram

• Dual HV power supply (0-5kV)

• Confocal optical scheme

• Remote control and problem debug

(via internet)



Results



121416181101121141161181

0

10000

20000

30000

40000

50000

60000

70000

80000

Static measure5ng/ul

0,5ng/ul

0,05ng/ul

100pM oligonucleotide labelled with CY 5

300

400

500

600

700

800

900

1000

1100

1200

1300

0 50 100 150 200Time [Sec.]

Co

un

ts [

c/s]

S/N=35

• Glass microchips purchased from Micralyne Inc. (Edmonton, Canada).• Electrosmotic flow in the separation channels suppressed by EPDMA • dynamic coating . • Separation run buffer: TAPS-TRIS 100mM pH 8.5.• Sample :23 mer oligonucleotide labelled with CY 5

• Detection limitDetection limit ( with S/N=3) :( with S/N=3) : 3pM3pM (with injection volume 50pL)



SPTM- Single Photon Timing Module

• Single power supply +15V• High Time-resolution (60ps) • Low dark Counts (down to 5 c/sec)• Controlled Temperature

• Software controlled settings• RS-232 data transmission

Politecnico di Milano

Single Molecole Detection Collaboration with S.XieHarvard Univ. Dept. Chemistry and Chemical Biology

FWHM=60ps




Prospect



• Improved optics sensitivity enhancement to 100fM

• Wider-area SPAD simpler set-up

• monolithic SPAD&AQC micro-miniaturized detection head

• SPAD arrays elaborate detection head

Prospect



Acknowledgments

Politecnico di Milano, Italy

Alessandro Restelli Electronics & Optics

Ivan Labanca

Dario Vagni

Giuseppe Liaci

Fabrizio Mingozzi ICRM-CNR, Milano, Italy:

Marcella CHIARI Polymers & Electrophoresis

Marina CRETICH

CEQSE-CNR, Milano, Italy:

Luciano PALLARO Mechanics & Optics



Thin SPAD’s Thick SPAD’s

• Good QE and low noise

• Picosecond timing

• Low voltage : 15 to 40V

• Low power : cooling not necessary

• Standard Si substrate

• Planar fabrication process

(compatible with IC integrated circuits)

• Robust and rugged

• Low-cost

• NO COMMERCIAL SOURCE TODAY

• Very good QE and low noise

• Sub-nanosecond timing

• High voltage : 300 to 400V

• High dissipation : Peltier cooler required

• Ultra-pure high-resistivity Si substrate

• Dedicated fabrication process

(NOT compatible with IC’s)

• Delicate and degradable

• Expensive

• SINGLE COMMERCIAL SOURCE

Documents

Ivan Rech Politecnico di Milano MICROELECTRONIC PHOTOSENSORS FOR GENETIC DIAGNOSTIC MICROSYSTEMS GE 2003, June 13, 2003 MICROELECTRONIC PHOTOSENSORS FOR