Abstract
Molecular Interferometric Imaging (MI2) is a sensitive detection platform for direct optical detection of immobilized biomolecules. It is based on inline common-path interferometry combined with far-field optical imaging. The substrate is a simple thermal oxide on a silicon surface with a thickness at or near the quadrature condition that produces a π/2 phase shift between the normal-incident wave reflected from the top oxide surface and the bottom silicon surface. The presence of immobilized or bound biomolecules on the surface produces a relative phase shift that is converted to a far-field intensity shift and is imaged by a reflective microscope onto a CCD camera. Shearing interferometry is used to remove the spatial 1/f noise from the illumination to achieve shot-noise-limited detection of surface dipole density profiles. The lateral resolution of this technique is diffraction limited at 0.4 micron, and the best longitudinal resolution is 10 picometers. The minimum detectable mass at the metrology limit is 2 attogram, which is 8 antibody molecules of size 150 kDa. The corresponding scaling mass sensitivity is 5 fg/mm compared with 1 pg/mm for typical SPR sensitivity. We have applied MI2 to immunoassay applications, and real-time binding kinetics has been measured for antibody-antigen reactions. The simplicity of the substrate and optical read-out make MI2 a promising analytical assay tool for high-throughput screening and diagnostics.
| Original language | English (US) |
|---|---|
| Title of host publication | Progress in Biomedical Optics and Imaging - Proceedings of SPIE |
| Volume | 6865 |
| DOIs | |
| State | Published - 2008 |
| Externally published | Yes |
| Event | Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications V - San Jose, CA, United States Duration: Jan 21 2008 → Jan 23 2008 |
Other
| Other | Nanoscale Imaging, Sensing, and Actuation for Biomedical Applications V |
|---|---|
| Country | United States |
| City | San Jose, CA |
| Period | 1/21/08 → 1/23/08 |
Fingerprint
Keywords
- Antibody
- BioCD
- Common-path interferometry
- Immunoassay
- Interference microscopy
- Molecular recognition
- Protein microarray
- Shot-noise limited detection
ASJC Scopus subject areas
- Engineering(all)
Cite this
Molecular interferometric imaging study of molecular interactions. / Zhao, Ming; Wang, Xuefeng; Nolte, David.
Progress in Biomedical Optics and Imaging - Proceedings of SPIE. Vol. 6865 2008. 68650B.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Molecular interferometric imaging study of molecular interactions
AU - Zhao, Ming
AU - Wang, Xuefeng
AU - Nolte, David
PY - 2008
Y1 - 2008
N2 - Molecular Interferometric Imaging (MI2) is a sensitive detection platform for direct optical detection of immobilized biomolecules. It is based on inline common-path interferometry combined with far-field optical imaging. The substrate is a simple thermal oxide on a silicon surface with a thickness at or near the quadrature condition that produces a π/2 phase shift between the normal-incident wave reflected from the top oxide surface and the bottom silicon surface. The presence of immobilized or bound biomolecules on the surface produces a relative phase shift that is converted to a far-field intensity shift and is imaged by a reflective microscope onto a CCD camera. Shearing interferometry is used to remove the spatial 1/f noise from the illumination to achieve shot-noise-limited detection of surface dipole density profiles. The lateral resolution of this technique is diffraction limited at 0.4 micron, and the best longitudinal resolution is 10 picometers. The minimum detectable mass at the metrology limit is 2 attogram, which is 8 antibody molecules of size 150 kDa. The corresponding scaling mass sensitivity is 5 fg/mm compared with 1 pg/mm for typical SPR sensitivity. We have applied MI2 to immunoassay applications, and real-time binding kinetics has been measured for antibody-antigen reactions. The simplicity of the substrate and optical read-out make MI2 a promising analytical assay tool for high-throughput screening and diagnostics.
AB - Molecular Interferometric Imaging (MI2) is a sensitive detection platform for direct optical detection of immobilized biomolecules. It is based on inline common-path interferometry combined with far-field optical imaging. The substrate is a simple thermal oxide on a silicon surface with a thickness at or near the quadrature condition that produces a π/2 phase shift between the normal-incident wave reflected from the top oxide surface and the bottom silicon surface. The presence of immobilized or bound biomolecules on the surface produces a relative phase shift that is converted to a far-field intensity shift and is imaged by a reflective microscope onto a CCD camera. Shearing interferometry is used to remove the spatial 1/f noise from the illumination to achieve shot-noise-limited detection of surface dipole density profiles. The lateral resolution of this technique is diffraction limited at 0.4 micron, and the best longitudinal resolution is 10 picometers. The minimum detectable mass at the metrology limit is 2 attogram, which is 8 antibody molecules of size 150 kDa. The corresponding scaling mass sensitivity is 5 fg/mm compared with 1 pg/mm for typical SPR sensitivity. We have applied MI2 to immunoassay applications, and real-time binding kinetics has been measured for antibody-antigen reactions. The simplicity of the substrate and optical read-out make MI2 a promising analytical assay tool for high-throughput screening and diagnostics.
KW - Antibody
KW - BioCD
KW - Common-path interferometry
KW - Immunoassay
KW - Interference microscopy
KW - Molecular recognition
KW - Protein microarray
KW - Shot-noise limited detection
UR - http://www.scopus.com/inward/record.url?scp=42149128824&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=42149128824&partnerID=8YFLogxK
U2 - 10.1117/12.760783
DO - 10.1117/12.760783
M3 - Conference contribution
AN - SCOPUS:42149128824
SN - 9780819470409
VL - 6865
BT - Progress in Biomedical Optics and Imaging - Proceedings of SPIE
ER -