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Matrix interference resulting from the nonspecific adsorption of non-target components, particularly proteins (fouling), onto sensor surfaces poses a persistent challenge in electrochemical detection of food hazards. The development of antifouling sensor surfaces presents a viable approach to mitigate nonspecific adsorption. In this study, a novel antifouling electrochemical aptasensor, utilizing a zwitterionic polymer, was developed for the sensitive, accurate, and selective detection of tetracycline (TC) in milk. This sensor employs a poly (dopamine)-poly (sulfobetaine methacrylate) (PDA-PSBMA) antifouling copolymer, which is synthesized through an in-situ initiated copolymerization of dopamine on the sensor's surface. Subsequently, the thiol-containing aptamers were immobilized onto the PDA-PSBMA coating through a Michael addition reaction with the poly(dopamine). The resulting antifouling electrochemical aptasensor exhibited robust antifouling performance in various single protein solutions and diluted milk samples, coupled with sensitive and selective recognition of TC. The sensor demonstrated a broad linear response range of 0.1–1000.0 ng mL−1 and a low limit of detection (LOD) of 68.0 pg mL−1. The antifouling electrochemical aptasensor proved effective in assaying TC in diluted milk, with recoveries ranging from 100.0 % to 104.4 %, eliminating the need for additional pretreatments due to its exceptional resistance to nonspecific adhesion. [Display omitted] • DA self-polymerization initiated free radical polymerization of SBMA. • One-step prepared PDA-PSBMA copolymer showed excellent antifouling ability. • Thiol-containing aptamer was introduced by a Michael addition reaction with the PDA. • An antifouling electrochemical aptasensor based on PDA-PSBMA was proposed. • Sensitive TC analysis in diluted milk can be realized without other pretreatments. [ABSTRACT FROM AUTHOR]

Nonspecific adsorption of non-target components (especially proteins) in food matrix on sensing surfaces deteriorates accuracy and sensitivity of electrochemical sensors, which is a key challenge for food safety sensing. Therefore, electrochemical sensors with antifouling capability of high-protein food matrices are highly desired. In this paper, an efficient and simple antifouling electrochemical aptasensor for tetracycline (TC) analysis was constructed based on a self-designed Y-shaped peptide [CPPPPEK-(RSERSERSE) 2 ] consisting of cysteine as the anchoring segment, polyproline as the supporting segment, and -EK-(RSERSERSE) 2 as antifouling branches. Hydrophilic and electrically neutral amino acid sequence and Y-shaped space structure of the peptide endow the sensing surface with good antifouling performance in protein solutions and diluted milk. Under optimized experiment conditions, the proposed aptasensor can detect TC with a wide linear range (0.01–100 ng mL−1) and a limit of detection of 5.3 pg mL−1 (S/N = 3). The spiked recovery experiments confirmed high accuracy of the aptasensor in diluted milk without other pretreatments (recoveries: 90.96%–95.86%). This strategy offers a valid way to reduce matrix interference, showing a promise to be extended to other sensing systems for different targets. [Display omitted] • An innovative electrochemical aptasensor was developed for TC determination. • It consists of CPPPPEK-(RSERSERSE) 2 and specific aptamer. • The Y-shaped peptide endowed the aptasensor with excellent antifouling ability. • The proposed sensor has satisfactory selectivity, repeatability and stability. [ABSTRACT FROM AUTHOR]

Interference derived from nonspecific attachment of foulants (e.g. proteins) from food matrices (fouling) on sensor surfaces has always been a major issue in food safety sensing, deteriorating the stability and accuracy of detection. Engineering and introducing antifouling materials on sensors to strongly hydrate their surfaces is a promising approach to address this issue. Here, inspired by a bioactive peptide with antithrombotic function, a nove l antifouling zwitterionic peptide (Z-peptide) with a sequence of NH 2 -CPPPPEKDQDK (C′−N') was designed. The antifouling performance of the proposed Z-peptides modified sensor surface was demonstrated in different protein solutions and milk samples (signal suppression rate as low as 1.87%). Molecular dynamics (MD) simulations reveal that a large number of hydrogen bonds and strong interaction forces are formed between Z-peptides and water molecules, contributing to the formation of a dense hydration layer on the sensor surface to resist nonspecific adsorption. An electrochemical aptasensor based on the Z-peptide was developed for tetracycline (TC) detection. The proposed sensor was able to detect TC with a wide linear range (0.01–100 ng mL−1) and a low limit of detection (LOD = 2.91 pg mL−1, S/N ﹦3) and showed favorable specificity and stability. Given the excellent resistance to nonspecific adsorption, the antifouling sensor was capable of assaying TC in milk by diluting without other pretreatments (recoveries: 107.17%–110.16%). • A novel bioactive peptide-inspired antifouling zwitterionic peptide was designed. • The powerful hydrophilicity of the zwitterionic peptides was proved. • Sensor surface based on zwitterionic peptides shows a good antifouling effect. • An electrochemical aptasensor based the antifouling surface was developed. • The proposed sensor performed well in assaying TC residue in diluting milk samples. [ABSTRACT FROM AUTHOR]