Dual-functional carbon dots/monolayer Ti3C2TX heterojunction material applying for highly sensitive fluorescence detection of histamine and visual monitoring of seafood freshness

In this study, an innovative dual-functional zero-dimensional/two-dimensional carbon dots/monolayer Ti 3 C 2 T X (CDs/mon.Ti 3 C 2 T X ) heterojunction material was developed for sensitive fluorescence detection of histamine (HA) and visual monitoring of food freshness. Through electrostatic adsorption and hydrogen bonding, CDs were uniformly anchored onto the surface of mon.Ti 3 C 2 T X , forming a stable 0D/2D heterojunction structure. This architecture not only facilitated efficient charge separation but also promoted the interaction with and enrichment of HA, thereby enhancing the fluorescence response. In the fluorescence detection mode, the CDs/mon.Ti 3 C 2 T X heterojunction exhibited an excellent linear response to HA in the concentration range of 0.01–5 mg/mL ( R 2 = 0.9925), with a detection limit of 0.0065 mg/mL, demonstrating acceptable sensitivity and good stability. Moreover, the heterojunction enabled visual monitoring of food freshness through distinct color changes under natural light. By integrating fluorescence-based HA detection with visual freshness monitoring, this work provides an efficient, and practical strategy for biogenic amine detection in food and freshness evaluation of perishable seafood, highlighting its promising potential for food quality and safety assessments.