Optofluidic Microsystems
based on Silicon Photonic Crystals:
A New Three-Dimensional Platform
for Label-Free Biosensing Applications
Sabina Merlo, Valerio Annovazzi-Lodi
Mauro Benedetti, Sergio Riccardi
Electrooptics Lab
Dept. of Electronics
Università di Pavia
Available grants
CARIPLO 2007
Development of an optical biosensor for the detection of
amyloid fibrils-ligands interactions on a silicon
micromachined structure
UniPv - UniGe - UniPi
PRIN-COFIN 2007
Photonic Crystal Optofluidic Microsystems for Biosensing
UniPi - UniPv - IFAC CNR Fi
Monitoring interactions between
bioreceptors immobilized on Silicon and possible ligands
Functionalized
matrix
Silicon
Input
light
Bioreceptor
Analyte or Ligand
Reflected
light
Reflectivity
Input
light
Reflected
light
Wavelength [µm]
Monitoring the growth of biological nanostructures
Input
light
Silicon
Starting seed
Protein
Reflected
light
Reflectivity
Input
light
Reflected
light
Wavelength [µm]
The Silicon device
SM-FO experimental setup for
reflection measurements
Features and advantages
 It is a platform:
specificity is given by bioreceptors or immobilized seeds
 High aspect-ratio device: three-dimensional supporting
microstructure for biological nanostructures
 Silicon micromachined structures
 are easy to fabricate and can be functionalized
 form small size sensors: 100 µm x 100 µm x 100 µm
 can be integrated with:
microfluidic devices and read-out optical fibres
 One-dimensional periodic structures
 Show photonic band gaps
 Reflectivity spectrum strongly depends on thickness and
refractive index of material covering the silicon walls
 Label-free optical detection: no dyes or fluorescent probes
Bibliography
Barillaro G., Diligenti A., Benedetti M., Merlo S., Silicon micromachined
periodic structures for optical applications at λ=1.55 µm, Applied Physics
Letters, 2006, Vol. 89, Article no. 151110
Barillaro G., Annovazzi-Lodi V., Benedetti M., Merlo S., Reflection
properties of hybrid quarter-wavelength silicon microstructures, Applied
Physics Letters, 2007, Vol. 90, Article no. 121110
Barillaro G., Merlo S., Strambini L, Band gap tuning of silicon
micromachined 1D photonic crystals by thermal oxidation, IEEE Journal of
Selected Topics in Quantum Electronics (Special Issue on Semiconductor
Photonic Materials, 2008) 14(4), 2008
Barillaro G., Strambini L, Annovazzi-Lodi V. Merlo S., Optical
Characterization of High-Order 1D Silicon Photonic Crystals, IEEE Journal
of Selected Topics in Quantum Electronics (Special Issue on Nanophotonics
and Optical Mems, 2009) 15(5), 2009
Attività didattica relativa a Biofotonica-Biosensori ottici
presso la facoltà di Ingegneria dell'Università di Pavia
Sabina Merlo è
• titolare del corso di
“Optoelettronica Biomedica” (5 Cr) dal 2004
Insegnamento per la Laurea Specialistica di Ingegneria
Biomedica, della Facoltà di Ingegneria dell’Università di
Pavia. (30-50 studenti/anno).
• relatore di tesi di Laurea Specialistica in Ingegneria
Biomedica, svolte sia presso il Laboratorio di Elettroottica
del Dip. di Elettronica sia presso aziende
(STMicroelectronics)