Label-free detection of uric acid using a disposable poly-N- isopropylacrylamide as an encapsulating enzyme material based on high-κ Eu2Ti2O7 electrolyte-insulator-semiconductor devices

Tung Ming Pan*, Kung Yuan Chang, Chao Wen Lin, Shiao Wen Tsai, Min Hsien Wu

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

6 Scopus citations

Abstract

In this paper, we proposed a disposable poly-N-isopropylacrylamide (PNIPAAm) as an encapsulating enzyme material based an electrolyte-insulator- semiconductor (EIS) device for uric acid biosensing, prepared from high-κ Eu2Ti2O7 sensing membranes. We used X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy to examine the structural and morphological features of these membranes annealed at different annealing temperatures. The Eu2Ti2O7 EIS device annealed at 900 °C exhibited a higher sensitivity (59.03 mV/pH), a lower drift rate (0.586 mV/h), and a smaller hysteresis voltage (2.8 mV) compared to those of the other annealing temperatures, presumably because of its lower number of crystal defects and its higher surface roughness. Furthermore, for a high-κ Eu2Ti2O7 EIS biosensor, a disposable PNIPAAm was used as an encapsulating enzyme material, making the loading and removal of a biological recognition element on a biosensor easily. PNIPAAm film has reversible solubility to become a solution-gelatin state change in response to thermal condition (∼32 °C). Below the phase transition temperature, such a PNIPAAm film exhibits a higher solubility in water, whereas this film becomes a gel state if the temperature increases. The sensitivity of an uricase-immobilized EIS biosensor was 17.6 mV/mM for uric acid concentrations ranging from 2 to 8 mM.

Original languageEnglish
Pages (from-to)850-857
Number of pages8
JournalSensors and Actuators, B: Chemical
Volume160
Issue number1
DOIs
StatePublished - 15 12 2011

Keywords

  • Electrolyte-insulator-semiconductor (EIS)
  • EuTi O
  • Poly-N-isopropylacrylamide (PNIPAAm)
  • Uric acid
  • pH sensitivity

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