BioChip Journal

, Volume 12, Issue 4, pp 317–325 | Cite as

Effects of Ionic Strength in the Medium on Sample Preconcentration Utilizing Nano-interstices between Self-Assembled Monolayers of Gold Nanoparticles

  • Ngoc-Viet Nguyen
  • Jian-Sheng Wu
  • Chun-Ping JenEmail author
Original Article


This paper investigated the effects of ionic strength in the medium on a preconcentrator for a protein sample with low concentration. The preconcentration chip was designed and fabricated using a polydimethylsiloxane replica through standard lithophotography. A glass substrate is silanized prior to functionalizing the nanoparticles for self-assembly at a designed region. Due to the overlap of electrical double layers in a nanofluidic channel, a concentration polarization effect can be achieved using an electric field. A nonlinear electrokinetic flow is induced, resulting in the fast accumulation of proteins in front of the induced ionic depletion zone, so called exclusion-enrichment effect. Thus, the protein sample can be driven by electroosmotic flow and accumulated at a specific location. The chip is used to collect fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) diluted in phosphate- buffered saline (PBS) buffer solution. Different concentrations of the buffer media were studied herein. Fluorescence intensity images show that the buffer concentration of 4 mM is more appropriate than all the other ones. The sample of FITC-BSA with an initial concentration of 10 μM in the 4 mM PBS solution increases its concentration at the desired region by up to 50 times within 30 min, demonstrating the results in this investigation.


Protein preconcentrator Microfluidics Nanochannel Buffer solution 


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Copyright information

© The Korean BioChip Society and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringNational Chung Cheng UniversityChia-YiTaiwan, Republic of China

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