The selective and highly sensitive detection of trace tetracycline antibiotic residues is crucial for ensuring food safety and maintaining organismal health. In the present study, we describe a novel method for tetracycline detection utilizing phosphorus-doped carbon quantum dots (P-CQDs) synthesized via solid-phase pyrolysis as fluorescent probes. Phosphorus doping significantly amplifies the fluorescence intensity by a factor of 8.1, and the resulting P-CQDs exhibit superior optical stability. The excitation and emission maxima of the P-CQDs are located at 340 nm and 440 nm, respectively. The fluorescent probe detects tetracycline based on the inner filter effect, demonstrating high selectivity and strong interference resistance. It has a wide detection range of 0–80 μM and a low detection limit of 0.120 μM. This method has been effectively applied to the analysis of real samples, yielding satisfactory results.

Liver injury remains a major clinical challenge due to the limited bioavailability and potential immunogenicity of conventional therapeutics. Microspheres derived from traditional Chinese medicine (TCM) polysaccharides have attracted increasing attention owing to their biocompatibility and immunoregulatory activities. However, most conventional delivery systems rely primarily on passive accumulation within inflammatory microenvironments, lacking effective injury-targeting capabilities. In this study, we constructed a biomimetic self-assembled microsphere system (Se-AAP/CG/Pm) using selenized Angelica-Astragalus compound polysaccharides (Se-AAP) and cationic gelatin (CG), followed by functionalization with a platelet membrane (Pm) coating via electrostatic adsorption. The resulting microspheres exhibited a nearly spherical morphology, a uniform particle size of 1.5–2 μm, good dispersion stability, and excellent blood compatibility (hemolysis rate < 5%). In vitro evaluation using the MTT assay demonstrated that Se-AAP/CG/Pm microspheres significantly enhanced the metabolic activity of AML-12 hepatocytes and LX-2 hepatic stellate cells while maintaining good cytocompatibility. In a CCl ₄ -induced acute liver injury mouse model, Se-AAP/CG/Pm microspheres markedly reduced serum levels of alanine aminotransferase and aspartate aminotransferase, alleviated hepatocellular necrosis and inflammatory infiltration, and exhibited favorable in vivo safety and hepatoprotective effects. This biomimetic system integrates the bioactivity of selenized TCM polysaccharides with the injury-targeting affinity of platelet membranes, providing a stable and reproducible strategy for platelet membrane-mediated intervention in acute liver injury.