Formulation, Physicochemical Optimization, and Forensic Evaluation of Zinc Oxide- and Curcumin-Loaded Solid Lipid...

Purpose: Nano-forensics is the latest application of nano-based technology for the purpose of fingerprint detection to improve precision, expedite investigations, and enhance safety. Solid lipid nanoparticles (SLNs) represent a promising pharmaceutical nanocarrier system for different applications. This study focused on applying ZnO and/or curcumin nanoparticles (NPs) to SLNs for the purpose of fingerprint detection to improve their sensitivity, safety and selectivity. Methods: A factorial design was utilized to select the optimized Cur-SLNs and ZnO-SLNs on the basis of the smallest particle size (PS), the lowest polydispersity index (PDI) and the highest zeta potential (ZP) value. To select the safe SLN-NPs, a cytotoxicity test was applied and they were compared to the most commonly applied product in fingerprint detection. The optimized formula was investigated according to the morphological structure; confocal spectroscopy and a stability study at different storage conditions were applied. Then the SLN-NPs were evaluated for their sensitivity, efficacy and selectivity in fingerprint detection. Results: The obtained optimal Cur-SLNs and ZnO-SLNs showed a nano PS of 221.55 ± 1.34 nm and 313.950 ± 1.87 nm, respectively, a PDI value < 0.7 and a ZP > 20 mV. The cytotoxicity data demonstrate that Cur-SLNs have low toxicity, so they will be the chosen formula. TEM and Raman spectroscopy analysis of the optimized Cur-SLN formulation validated the encapsulation efficiency and structural integrity of the pharmaceutical nanosystem. Furthermore, the powder showed stability and good results with higher adherence but smudged the prints on surfaces due to the slightest moisture. Conclusions: Overall, the results confirmed that Cur-SLN nanopowders can be developed as a suggested alternative to the current toxic powders used for latent fingerprint detection in forensic science, but only after further research on various surfaces and in different conditions.