Amine-responsive cellulose-based ratiometric fluorescent materials for real-time and visual detection of shrimp and crab freshness

TLDR

The study designs cellulose‑based ratiometric fluorescent materials that enable real‑time, visual detection of seafood freshness via amine responsiveness. The authors covalently attach FITC and PpIX to cellulose acetate, blend them in varying ratios to produce dual‑emission solids, and process the resulting materials into inks, coatings, films, and nanofibrous membranes. The materials show a rapid, color‑changing, linear response to ammonia from 5.0 ppm to 2.5 × 10⁴ ppm, and the electrospun nanofibrous membrane enables low‑cost, high‑contrast visual monitoring of shrimp and crab freshness.

Abstract

Abstract Herein, we design and prepare cellulose-based ratiometric fluorescent materials with superior amine-response, which offers the real-time and visual detection of seafood freshness. Through utilizing the reactive hydroxyl groups along cellulose chains, we covalently immobilize the fluorescein isothiocyanate (FITC) as indicator and protoporphyrin IX (PpIX) as internal reference onto cellulose acetate (CA), respectively. Subsequently, a series of dual-emission solid fluorescent materials are achieved by simply blending green emitting CA-FITC with red-emitting CA-PpIX with varying ratios. They exhibit a sensitive, color-responsive, rapid and linear response to ammonia in a wide range of 5.0 ppm to 2.5 × 10 4 ppm. Benefiting from the excellent solubility and processibility of cellulose derivatives, the as-prepared materials are readily processed into different material forms, including printing ink, coating, flexible film, and nanofibrous membrane. The electrospun nanofibrous membrane is successfully employed as a low-cost, high-contrasting, quick-responsive fluorescent trademark for visual monitoring the freshness of shrimp and crab.