TY - JOUR

T1 - On Chip Protein Pre-Concentration for Enhancing the Sensitivity of Porous Silicon Biosensors

AU - Arshavsky-Graham, Sofia

AU - Massad-Ivanir, Naama

AU - Paratore, Federico

AU - Scheper, Thomas

AU - Bercovici, Moran

AU - Segal, Ester

N1 - Funding information: This work was partially supported by the NEVET grant administrated by the Russell Berrie Nanotechnology Institute (RBNI), by the German Research Foundation under the grant SCHE 279/32-1 and by the Initial Training Network, Virtual Vials, funded by the FP7 Marie Curie Actions of the European Commission (FP7-PEOPLE-2013-ITN-607322). The oxidation process was performed at the Micro-Nano Fabrication Unit (MNFU), Technion. The authors thank Dr. Khaled Gommed for his assistance in preparation of the microfluidic channels and Prof. Yuval Shoham from the Department of Biotechnology and Food Engineering at the Technion for supplying the target protein. S.A.-G. is most grateful for the Miriam and Aaron Gutwirth scholarship and for TEVA Pharmaceutical Industries Excellence Scholarship for M.Sc. students in Analytical Chemistry.

PY - 2017/11/22

Y1 - 2017/11/22

N2 - Porous silicon (PSi) nanomaterials have been widely studied as label-free optical biosensors for protein detection. However, these biosensors' performance, specifically in terms of their sensitivity (which is typically in the micromolar range), is insufficient for many applications. Herein, we present a proof-of-concept application of the electrokinetic isotachophoresis (ITP) technique for real-time preconcentration of a target protein on a PSi biosensor. With ITP, a highly concentrated target zone is delivered to the sensing area, where the protein target is captured by immobilized aptamers. The detection of the binding events is conducted in a label-free manner by reflective interferometric Fourier transformation spectroscopy (RIFTS). Up to 1000-fold enhancement in local concentration of the protein target and the biosensor's sensitivity are achieved, with a measured limit of detection of 7.5 nM. Furthermore, the assay is successfully performed in complex media, such as bacteria lysate samples, while the selectivity of the biosensor is retained. The presented assay could be further utilized for other protein targets, and to promote the development of clinically useful PSi biosensors.

AB - Porous silicon (PSi) nanomaterials have been widely studied as label-free optical biosensors for protein detection. However, these biosensors' performance, specifically in terms of their sensitivity (which is typically in the micromolar range), is insufficient for many applications. Herein, we present a proof-of-concept application of the electrokinetic isotachophoresis (ITP) technique for real-time preconcentration of a target protein on a PSi biosensor. With ITP, a highly concentrated target zone is delivered to the sensing area, where the protein target is captured by immobilized aptamers. The detection of the binding events is conducted in a label-free manner by reflective interferometric Fourier transformation spectroscopy (RIFTS). Up to 1000-fold enhancement in local concentration of the protein target and the biosensor's sensitivity are achieved, with a measured limit of detection of 7.5 nM. Furthermore, the assay is successfully performed in complex media, such as bacteria lysate samples, while the selectivity of the biosensor is retained. The presented assay could be further utilized for other protein targets, and to promote the development of clinically useful PSi biosensors.

KW - aptamer

KW - isotachophoresis

KW - label-free

KW - optical biosensor

KW - porous silicon

UR - http://www.scopus.com/inward/record.url?scp=85039169604&partnerID=8YFLogxK

U2 - 10.1021/acssensors.7b00692

DO - 10.1021/acssensors.7b00692

M3 - Article

C2 - 29164872

AN - SCOPUS:85039169604

VL - 2

SP - 1767

EP - 1773

JO - ACS SENSORS

JF - ACS SENSORS

SN - 2379-3694

IS - 12

ER -