1,8-Naphthalimide-based hybrid inorganic–organic materials for visualization of latent fingerprints: Intracellular Cu2+ detection and anti-counterfeiting ink

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 468; p. 116495
• Main Authors: Thakur, Vishakha, Kumar, Sanjeev, Kaur, Mandeep, Sharma, Ananay, Ahmad, Sheikh Showkat, Kaur, Satwinderjeet, Singh, Prabhpreet
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2025
• Subjects: 1,8-Naphthalimide; Cu2; Hybrid materials; Latent fingerprinting; Security ink; Sweat pores; Cu2; Sweat pores; 1,8-Naphthalimide; Hybrid materials; Latent fingerprinting; Security ink
• ISSN: 1010-6030
• DOI: 10.1016/j.jphotochem.2025.116495

Functionalized 1,8-naphthalimide (NBG) for intracellular Cu2+ detection, security ink and NBG-based hybrid materials for the imaging of latent fingerprints on different surfaces up to level 3 is reported. [Display omitted] •NBG was used for detection of Cu2+ ions in HeLa cells, 20 % HEPES buffer and CH3CN.•Preparation of silica and Montmorillonite clay adsorbed inorganic–organic hybrid materials.•Development and imaging of LFPs or physically stressed LFPs on 13–16 different surfaces.•Visualization of level 3 (Sweat pores) including incipient ridges and details of the ridges.•Preparation of NBG solution in ethanol and ethanol–glycerol (7:3, v/v) as the security ink. The ethylene glycol appended 4,5-disubstituted-1,8-naphthalimide (NBG) is reported for the detection of the Cu2+ ions in aqueous medium, live cells and for the imaging of latent fingerprints (LFPs). The NBG showed a decrease in the fluorescence and absorbance intensities at 382 and 446 nm, respectively upon addition of Cu2+ ions in 20 % HEPES buffer–CH3CN medium or CH3CN with limit of detection as low as 90 nM (in CH3CN). The solution of NBG in ethanol and ethanol–glycerol (7:3, v/v) has been explored as the security ink to write full page text, drawings and chemical structures with ease. The NBG was non-covalently adsorbed on silica nanoparticles (NBG@SiO2) and Montmorillonite clay (NBG@MM) to make hybrid inorganic–organic materials for the imaging of latent fingerprints on 13–16 different surfaces up to levels 1–3. The NBG@SiO2 and NBG@MM fluorescent powders showed sebaceous content enhanced visualization of LFPs on different surfaces and can be used for the analysis, differentiation of different subjects. The physically stressed LFPs have been successfully developed using NBG@ SiO2 and NBG@MM fluorescent powders with excellent contrast.