Gold-based nanostructured platforms for oxytetracycline detection from milk by a “signal-on” aptasensing approach

•Electrodeposition of five new gold platforms at screen printed electrodes.•Morphology and topography are strongly influenced by the deposition procedure.•Ferrocene-Aptamer immobilization was investigated at five gold platforms.•The thistle-like structures were optimal for aptasensor development.•The aptasensor displayed good recovery values towards Oxytetracycline in milk samples.