Acriflavine-immobilized eggshell membrane as a new solid-state biosensor for Sudan I-IV detection based on fluorescence resonance energy transfer.

A novel solid-surface fluorescence biosensor for rapid detection of Sudan I-IV was proposed based on fluorescence resonance energy transfer (FRET). The biosensor was fabricated by immobilizing acriflavine (AY) on the eggshell membrane (ESM) with glutaraldehyde as cross-linking agent. FRET mechanism was demonstrated by using AY and Sudan dyes as donor and acceptor respectively, an efficient energy transfer in the present system was indicated by the sufficient spectral overlap integral (J) and proper Förster critical distance (R). Under optimum conditions, the fluorescence of the AY-ESM could be efficiently quenched by Sudan I-IV and the corresponding linear range was 0.5-60μM with the detection limits (3σ/slope) of 0.16, 0.26, 0.21 and 0.17μM respectively. Compared to the detection of Sudan dyes in solution-state, the membrane biosensor exhibited advantages of low detection limits, high sensitivity and selectivity, as well as excellent stability. Recovery tests in spiked real samples also achieved satisfactory results.