Direct and label-free determination of human glycated hemoglobin levels using bacteriorhodopsin as the biosensor transducer

Ying Chin Lin, Ching Yu Lin, Hsiu Mei Chen, Li Pin Kuo, Cheng En Hsieh, Xiang He Wang, Chih Wen Cheng, Chih Yin Wu, Yi Su Chen

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Glycated hemoglobin (HbA1c) levels are an important index for the diagnosis and long-term control of diabetes. This study is the first to use a direct and label-free photoelectric biosensor to determine HbA1c using bacteriorhodopsin-embedded purple membranes (PM) as a transducer. A biotinylated PM (b-PM) coated electrode that is layered with protein A-oriented antibodies against hemoglobin (Hb) readily captures non-glycated Hb (HbA0) and generates less photocurrent. The spectra of bacteriorhodopsin and Hb overlap so the photocurrent is reduced because of the partial absorption of the incident light by the captured Hb molecules. Two HbA0 and HbA1c aptasensors that are prepared by conjugating specific aptamers on b-PM coated electrodes single-step detect HbA0 and HbA1c in 15 min, without cross reactivity, with detection limits of ≤0.1 µg/mL and a dynamic range of 0.1–100 µg/mL. Both aptasensors exhibit high selectivity and long-term stability. For the clinical samples, HbA0 concentrations and HbA1c levels that are measured with aptasensors correlate well with total Hb concentrations and the HbA1c levels that are determined using standard methods (correlation gradient = 0.915 ± 0.004 and 0.981 ± 0.001, respectively). The use of these aptasensors for diabetes care is demonstrated.

Original languageEnglish
Article number7274
Pages (from-to)1-14
Number of pages14
JournalSensors (Switzerland)
Issue number24
Publication statusPublished - Dec 2 2020


  • Bacteriorhodopsin
  • Glycated hemoglobin
  • Photoelectric biosensor
  • Purple membrane

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Atomic and Molecular Physics, and Optics
  • Instrumentation
  • Electrical and Electronic Engineering


Dive into the research topics of 'Direct and label-free determination of human glycated hemoglobin levels using bacteriorhodopsin as the biosensor transducer'. Together they form a unique fingerprint.

Cite this