Aptamer-based photonic crystals enable ultra-trace detection of staphylococcal enterotoxin B without labels.

Staphylococcal enterotoxin B (SEB) is one of the most common serotypes in staphylococcal food-poisoning cases. A rapid, sensitive, and simple method for SEB detection is crucial for public health. A photonic crystal (PC) sensing material for label-free detection of ultra-trace SEB was proposed in this study. Gold nanoparticle-doped silica microspheres were stacked to form an opal PC through self-assembly, and SEB aptamers, as the recognition element, were modified onto the PC. When the target protein of SEB came in contact with the PC sensing material, the reflection peak intensity of PCs decreased accordingly. The detection range was 1 × 10-6 to 1 ng mL-1, and the detection limit was 0.103 × 10-6 ng mL-1. Furthermore, the PC sensing material had great specificity and accuracy, which can be used for real sample monitoring. This PC sensing material achieved ultra-sensitive detection, which did not involve complicated preparation processes and reporter labelling.