title: Lensfree optofluidic plasmonic sensor for real-time and label-free monitoring of molecular binding events over a wide field-of-view.
abstract: We demonstrate a high-throughput biosensing device that utilizes microfluidics based plasmonic microarrays incorporated with dual-color on-chip imaging toward real-time and label-free monitoring of biomolecular interactions over a wide field-of-view of >20 mm(2). Weighing 40 grams with 8.8 cm in height, this biosensor utilizes an opto-electronic imager chip to record the diffraction patterns of plasmonic nanoapertures embedded within microfluidic channels, enabling real-time analyte exchange. This plasmonic chip is simultaneously illuminated by two different light-emitting-diodes that are spectrally located at the right and left sides of the plasmonic resonance mode, yielding two different diffraction patterns for each nanoaperture array. Refractive index changes of the medium surrounding the near-field of the nanostructures, e.g., due to molecular binding events, induce a frequency shift in the plasmonic modes of the nanoaperture array, causing a signal enhancement in one of the diffraction patterns while suppressing the other. Based on ratiometric analysis of these diffraction images acquired at the detector-array, we demonstrate the proof-of-concept of this biosensor by monitoring in real-time biomolecular interactions of protein A/G with immunoglobulin G (IgG) antibody. For high-throughput on-chip fabrication of these biosensors, we also introduce a deep ultra-violet lithography technique to simultaneously pattern thousands of plasmonic arrays in a cost-effective manner.
authors.affiliation: 1] Departments of Electrical Engineering and Bioengineering, University of California, Los Angeles (UCLA), CA 90095, USA [2] Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125.
authors.forename: Ahmet F
authors.initials: AF
authors.lastname: Coskun
authors.affiliation: 1] Department of Electrical and Computer Engineering, Boston University, MA 02215, USA [2] Bioengineering Department, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne CH-1015 Switzerland.
authors.forename: Arif E
authors.initials: AE
authors.lastname: Cetin
authors.affiliation: 1] Department of Electrical and Computer Engineering, Boston University, MA 02215, USA [2] Pontificia Universidad Catolica del Peru, Departamento de Ciencias-Quimica, Avenida Universitaria 1801, Lima 32, Peru.
authors.forename: Betty C
authors.initials: BC
authors.lastname: Galarreta
authors.affiliation: Department of Electrical and Computer Engineering, Boston University, MA 02215, USA.
authors.forename: Daniel Adrianzen
authors.initials: DA
authors.lastname: Alvarez
authors.affiliation: 1] Department of Electrical and Computer Engineering, Boston University, MA 02215, USA [2] Bioengineering Department, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne CH-1015 Switzerland.
authors.forename: Hatice
authors.initials: H
authors.lastname: Altug
authors.affiliation: 1] Departments of Electrical Engineering and Bioengineering, University of California, Los Angeles (UCLA), CA 90095, USA [2] California NanoSystems Institute, University of California, Los Angeles (UCLA), CA 90095, USA.
authors.forename: Aydogan
authors.initials: A
authors.lastname: Ozcan
mesh_terms: D015374:Biosensing Techniques; D044085:Microfluidics; D025941:Protein Interaction Mapping / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D012680:Sensitivity and Specificity