Dielectrophoresis-Based Protein Enrichment for a Highly Sensitive Immunoassay Using Ag/SiO2 Nanorod Arrays

Zhen Cao, Yu Zhu, Yang Liu, Shurong Dong, Xin Chen, Fan Bai, Shengxin Song, Junxue FU*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

29 Citations (Scopus)


A nanoscale insulator-based dielectrophoresis (iDEP) technique is developed for rapid enrichment of proteins and highly sensitive immunoassays. Dense arrays of nanorods (NDs) by oblique angle deposition create a super high electric field gradient of 2.6 × 1024 V2 m−3 and the concomitant strong dielectrophoresis force successfully traps small proteins at a bias as low as 5 V. 1800-fold enrichment of bovine serum albumin protein at a remarkable rate of up to 180-fold s−1 is achieved using oxide coated Ag nanorod arrays with pre-patterned sawtooth electrodes. Based on this system, an ultrasensitive immunoassay of mouse immunoglobulin G is demonstrated with a reduction in the limit of detection from 5.8 ng mL−1 (37.6 pM) down to 275.3 fg mL−1 (1.8 f M), compared with identical assays performed on glass plates. This methodology is also applied to detect a cancer biomarker prostate-specific antigen spiked in human serum with a detection limit of 2.6 ng mL−1. This high sensitivity results from rapid biomarker enrichment and metal enhanced fluorescence through the integration of nanostructures. The concentrated proteins also accelerate binding kinetics and enable signal saturation within 1 min. Given the easy fabrication process, this nanoscale iDEP system provides a highly sensitive detection platform for point-of-care diagnostics.

Original languageEnglish
Article number1703265
Issue number12
Early online date26 Jan 2018
Publication statusPublished - 22 Mar 2018

Scopus Subject Areas

  • Biotechnology
  • Biomaterials
  • Chemistry(all)
  • Materials Science(all)

User-Defined Keywords

  • dielectrophoresis
  • immunoassays
  • oblique angle deposition
  • protein enrichment


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