Curcumin-Dragon's blood-chitosan nanosuspension for dual forensic detection

Forensic identification of latent fingerprints and bloodstains is fundamental to criminal investigations, yet conventional methods often suffer from high toxicity, low sensitivity, and substrate dependency. This study aims to address these limitations by developing a novel, biocompatible, dual-function nanosuspension formulation. The nanosuspension was synthesized using the ionic gelation method, crosslinking curcumin and Dragon's blood resin within a chitosan nanoparticle matrix using sodium tripolyphosphate (TPP). Formulation optimization was systematically performed using a Box-Behnken Design (BBD) to evaluate the impact of chitosan concentration, curcumin amount, and TPP concentration on particle properties. Forensic efficacy was assessed through fluorescence imaging and ridge detail analysis on both porous and non-porous substrates. The optimized formulation achieved highly favorable physicochemical properties, including an average particle size of 220.5 ± 5.4 nm, a stable negative zeta potential of - 31.2 ± 2.1 mV, and an encapsulation efficiency of 85.2 ± 3.1%. The nanosuspension demonstrated significant quantitative superiority in forensic application, yielding a ridge contrast ratio of 4.2 ± 0.3 compared to 2.1 ± 0.4 for standard powders. Strong fluorescence under UV illumination enabled clear visualization of fingerprints up to the 5th depletion and selective marking of bloodstains. Molecular docking confirmed a strong binding affinity of resin components with hemoglobin (8.2 kcal/mol, supporting the observed selective detection. The novel curcumin-Dragon's blood resin-chitosan nanosuspension provides a non-toxic, highly sensitive, and substrate-versatile dual-function reagent. This formulation represents a significant advancement in forensic evidence visualization with substantial potential for practical field deployment.