Novel nanocomposite of spiky-shaped gold nanourchins/ titanium dioxide/nafion for amplified signal and efficient electrochemiluminescence detection of ovomucoid

•First ultrasensitive electrochemiluminescence immunoassay for ovomucoid detection.•Novel nanocomposite of titanium dioxide, gold nanourchins and nafion were used.•Label-free cost effective, highly selective, and stable immunosensor up to 15 days.•Promising for real food sample analysis. This work reports on the first electrochemiluminescence (ECL) immunosensor employing a novel nanostructured composite of titanium dioxide (TiO2) and gold nanourchins (AuNU) to detect protein allergen Ovomucoid (Ovm) found in eggs. TiO2 and AuNU were dispersed in Nafion and drop-casted onto SPGE with Tris(2,2′-bipyridyl)-ruthenium (II) ([Ru(bpy)3]2+) and tri-n-propylamine (TPrA) served as strong luminophore/co-reactant pairs as a source of ECL signals. The linear range, limit of detection, reproducibility and practical applications of the sensor were assessed. The fabricated ECL immuosensor produced a promising limit of detection of as low as 0.01 pg/mL. Two linear ranges of 0.01–50 pg/mL and 100–750 pg/mL with corresponding correlation coefficients of R2 = 0.99136 and R2 = 0.97829) respectively, were determined. Despite its simple fabrication method, this label-free immunosensor also showcased excellent selectivity, reproducibility, interference-resistance and yielded outstanding recoveries between 97.42 and 104.05% of Ovm analysis in spiked real food samples.