Controlling food safety and preventing the growing spread of antibiotics into food products have been challenging problems for the protection of human health. Hence, the development of easy-to-use, fast, and sensitive analytical methods for the detection of antibiotics in food products has become one of the priorities in the food industry. In this paper, an electrochemical platform based on the ssDNA aptamer for the selective detection of tetracycline has been proposed. The aptasensor is based on a thiolated aptamer, labelled with ferrocene, which has been covalently co-immobilized onto a gold electrode surface with 6-mercaptohexan-1-ol. The changes in the redox activity of ferrocene observed on the aptamer–antibiotics interactions have been the basis of analytical signal generation registered by square-wave voltammetry. Furthermore, the detection of tetracycline-spiked cow milk samples has been successfully demonstrated. The limits of detection (LODs) have been obtained of 0.16 nM and 0.20 nM in the buffer and spiked cow milk, respectively, which exceed the maximum residue level (225 nM) more than 1000 times. The proposed aptasensor offers high selectivity for tetracycline against other structurally related tetracycline derivatives. The developed biosensor characterized by simplicity, a low detection limit, and high reliability shows practical potential for the detection of tetracycline in animal-origin milk.

Neurodegenerative diseases (NDs) are becoming a major global health problem. They constitute an incurable diverse group of disorders characterized by the progressive degeneration of the structure and function of the central or peripheral nervous system. There is an enormous unmet demand worldwide for methods for the early detection of ND biomarkers. The complexity of the molecular mechanisms underlying neuronal degeneration as well as the inhomogeneity of the patient population pose a great challenge for the development of early diagnostic tools. Various analytical technologies have been developed to meet this challenge. Among the various approaches reported so far, biosensors are powerful analytical implements that have been applied to detect biomarkers of NDs. Over the past decade, electrochemical aptasensors have been at the forefront of this development not only thanks to their low cost and simple design but also due to advances in nanomaterials modifying the surface of the transducers involved. The design of electrochemical aptasensors for the detection of ND biomarkers such as α-synuclein, amyloid β peptide, tau protein and human cellular prion protein were summarized and compared. Innovative strategies for increasing their sensitivity and selectivity were also pointed out. Undoubtedly, there is still a need for low-cost, fast and easy-to-use systems for the early detection of NDs.

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