A versatile fluorescent biosensor based on target-responsive graphene oxide hydrogel for antibiotic detection

• A fluorescent aptasensor based on target-responsive GO hydrogel was developed for the first time.
• Adenosine and aptamer worked as the co-crosslinkers to connect the GO sheets and form the 3D macrostructure.
• The detection process consisted of a simple hydrogel immersion and fluorescence determination in supernatant.
• A linear range of 25-1000 μg/L and a limit of quantitation of 25 μg/L toward target oxytetracycline (OTC) could be achieved.
• The aptasensor presents a generic detection approach for other molecules and the possibility for muti-targets.

A fluorescent sensing platform based on graphene oxide (GO) hydrogel was developed through a fast and facile gelation, immersion and fluorescence determination process, in which the adenosine and aptamer worked as the co-crosslinkers to connect the GO sheets and then form the three-dimensional (3D) macrostructures. The as-prepared hydrogel showed high mechanical strength and thermal stability. The optimal hydrogel had a linear response for oxytetracycline (OTC) of 25–1000 μg/L and a limit of quantitation (LOQ) of 25 μg/L. Moreover, together with the high affinity of the aptamer for its target, this assay exhibited excellent sensitivity and selectivity. According to its design principle, the as-designed hydrogel was also tested to possess the generic detection function for other molecules by simply replacing its recognition element, which is expected to lay a foundation to realize the assembly of functionalized hierarchical graphene-based materials for practical applications in analytical field.