TY - JOUR

T1 - Porous Silicon-Based Aptasensors

T2 - Toward Cancer Protein Biomarker Detection

AU - Arshavsky-Graham, Sofia

AU - Ward, Simon J.

AU - Massad-Ivanir, Naama

AU - Scheper, Thomas

AU - Weiss, Sharon M.

AU - Segal, Ester

N1 - Funding Information: This work was partially supported by the Israel Science Foundation (Grant 704/17), the German Research Foundation under Grant SCHE 279/32-1, and the National Institutes of Health (NIH) (Grant R21AI156693). We are grateful to Prof. Moran Bercovici and Dr. Federico Paratore for their help with the ITP experimental design. We also thank Dr. Khaled Gommed for his assistance in the preparation of the microfluidic channels and Reut Horev for her contribution to the biosensing experiments. E.S and S.A.-G acknowledge the the support of the Australian Technion Society as well as the core services and support from the Lorry I. Lokey Center for Life Science and Engineering.

PY - 2021/10/20

Y1 - 2021/10/20

N2 - The anterior gradient homologue-2 (AGR2) protein is an attractive biomarker for various types of cancer. In pancreatic cancer, it is secreted to the pancreatic juice by premalignant lesions, which would be an ideal stage for diagnosis. Thus, designing assays for the sensitive detection of AGR2 would be highly valuable for the potential early diagnosis of pancreatic and other types of cancer. Herein, we present a biosensor for label-free AGR2 detection and investigate approaches for enhancing the aptasensor sensitivity by accelerating the target mass transfer rate and reducing the system noise. The biosensor is based on a nanostructured porous silicon thin film that is decorated with anti-AGR2 aptamers, where real-time monitoring of the reflectance changes enables the detection and quantification of AGR2, as well as the study of the diffusion and target-aptamer binding kinetics. The aptasensor is highly selective for AGR2 and can detect the protein in simulated pancreatic juice, where its concentration is outnumbered by orders of magnitude by numerous proteins. The aptasensor’s analytical performance is characterized with a linear detection range of 0.05-2 mg mL-1, an apparent dissociation constant of 21 ± 1 μM, and a limit of detection of 9.2 μg mL-1 (0.2 μM), which is attributed to mass transfer limitations. To improve the latter, we applied different strategies to increase the diffusion flux to and within the nanostructure, such as the application of isotachophoresis for the preconcentration of AGR2 on the aptasensor, mixing, or integration with microchannels. By combining these approaches with a new signal processing technique that employs Morlet wavelet filtering and phase analysis, we achieve a limit of detection of 15 nM without compromising the biosensor’s selectivity and specificity.

AB - The anterior gradient homologue-2 (AGR2) protein is an attractive biomarker for various types of cancer. In pancreatic cancer, it is secreted to the pancreatic juice by premalignant lesions, which would be an ideal stage for diagnosis. Thus, designing assays for the sensitive detection of AGR2 would be highly valuable for the potential early diagnosis of pancreatic and other types of cancer. Herein, we present a biosensor for label-free AGR2 detection and investigate approaches for enhancing the aptasensor sensitivity by accelerating the target mass transfer rate and reducing the system noise. The biosensor is based on a nanostructured porous silicon thin film that is decorated with anti-AGR2 aptamers, where real-time monitoring of the reflectance changes enables the detection and quantification of AGR2, as well as the study of the diffusion and target-aptamer binding kinetics. The aptasensor is highly selective for AGR2 and can detect the protein in simulated pancreatic juice, where its concentration is outnumbered by orders of magnitude by numerous proteins. The aptasensor’s analytical performance is characterized with a linear detection range of 0.05-2 mg mL-1, an apparent dissociation constant of 21 ± 1 μM, and a limit of detection of 9.2 μg mL-1 (0.2 μM), which is attributed to mass transfer limitations. To improve the latter, we applied different strategies to increase the diffusion flux to and within the nanostructure, such as the application of isotachophoresis for the preconcentration of AGR2 on the aptasensor, mixing, or integration with microchannels. By combining these approaches with a new signal processing technique that employs Morlet wavelet filtering and phase analysis, we achieve a limit of detection of 15 nM without compromising the biosensor’s selectivity and specificity.

KW - Anterior Gradient Homologue-2

KW - Aptamer

KW - Cancer Biomarker

KW - Isotachophoresis

KW - Label-Free

KW - Microfluidics

KW - Optical Biosensor

KW - Porous Silicon

UR - http://www.scopus.com/inward/record.url?scp=85120796478&partnerID=8YFLogxK

U2 - 10.1021/acsmeasuresciau.1c00019

DO - 10.1021/acsmeasuresciau.1c00019

M3 - Article

AN - SCOPUS:85120796478

VL - 1

SP - 82

EP - 94

JO - ACS Measurement Science Au

JF - ACS Measurement Science Au

IS - 2

ER -