From Turmeric to Quantum Dots: The Green Revolution in Latent Fingerprint Detection

Latent fingerprints remain one of the most valuable forms of physical evidence in forensic identification, yet they are invisible to the naked eye and fragile enough to be destroyed before they can be recovered. A systematic review published in Discover Chemical Engineering has now brought together roughly 100 studies, published between 2001 and 2026, that evaluate the materials used to make these hidden ridge patterns visible, tracing a clear trajectory from conventional dusting powders toward nanotechnology-based fluorescent reagents, with a growing emphasis on non-toxic, low-cost and environmentally sustainable alternatives.

The review, conducted by C. P. Sintonа, D. Iyda Jenifer, Sindhu Subramaniam and A. Obadiah, searched databases including Google Scholar, ScienceDirect, SpringerLink, Wiley Online Library, PubMed, Taylor & Francis and ResearchGate using keywords such as latent fingerprint detection, fingerprint powders, small particle reagent, cyanoacrylate fuming, ninhydrin, nanoparticles and carbon dots. Studies were included only if they reported experimental evaluation of fingerprint development agents on porous or non-porous surfaces with clear results on ridge detail and visualization quality. The authors categorized the literature by material type, mechanism, substrate applicability and advantages.

The physical basis of powder dusting has changed little since the nineteenth century. Powder particles adhere to the lipids, sweat and other residues left in a fingerprint through a pressure deficit mechanism: when a particle is wetted by sweat deposition on its lower side, the meniscus of curvature creates a pressure deficit inside the droplet that pulls the particulate onto the print. Commercial powders combine a pigment with a binder so the powder sticks to the print without overwhelming the substrate, and the particle size, shape and density of the powder determine the quality of the developed fingerprint. Traditional formulations, however, often rely on titanium, lead and mercury-based powders whose toxicity has motivated the search for safer substitutes.

Plant-based powders are one prominent alternative. As early as 2011, Rakesh K. Garg and colleagues identified turmeric powder, derived from the rhizome Curcuma longa, as an effective, affordable and non-toxic fingerprint powder that yielded exceptionally clear results on the majority of nine surfaces tested. Subsequent studies examined Gambir plant powder, suitable for dry non-porous surfaces, acid-modified Imperata cylindrica powder, fluorophore-rich medicinal plant powders such as Zingiber montanum and Solanum indicum, neem and turmeric comparisons, onion powder, and floral powders. These materials work mainly through physical adhesion and hydrophobic attraction to the sebaceous fraction of fingerprint residue, particularly fatty acids, triglycerides, wax esters and squalene, which remain stable for long periods, with only minor weak hydrogen bonding to eccrine moisture and amino acids.

Household food powders form a second category. Richa Rohatgi’s team explored cocoa powder, custard powder, corn flour, baking soda, baking powder, black salt and turmeric as alternatives during shortages of conventional powders, while Harish Kumari’s group showed that synthetic food colours and festival colours such as gulal produced clear results, particularly on aluminium matrices. Venkatesh and colleagues tested edible food colouring powders on CDs, glass bottles, mirrors and steel bottles, finding that red and black dyes gave consistently high clarity and turquoise performed especially well on glass. Buckwheat flour, roasted gram flour (sattu), water chestnut flour and pomegranate peel powder, whose tannins and polyphenols interact with sebaceous and eccrine residues, have all been evaluated as inexpensive, non-toxic developers.

Mineral powders occupy a middle ground between tradition and innovation. Silica gel G has been applied to substrates ranging from plastic and glass to CDs and glossy magazine paper; marble slurry powder, predominantly calcium carbonate from construction waste, produced clear prints on ten porous and non-porous surfaces through interaction with fatty acids and oils in sweat; and Fuller’s earth (Multani mitti) adhered robustly to sebaceous ridges on glass, metal, wood and plastic. The review notes, however, that Fuller’s earth enhancement, while producing clear ridge detail that lasted up to six days, becomes weaker and less contrasted over time, prompting calls for studies on organic cosmetic compounds to improve contrast and durability.

For wet, non-porous surfaces, where conventional dusting fails, small particle reagent (SPR) techniques dominate. SPR suspends fine particles with dyes such as basic fuchsin or crystal violet, which attach through hydrophobic interactions to the sebaceous lipid fraction, the component that survives submersion while eccrine secretions wash away. A fluorescent SPR based on basic zinc carbonate outperformed the traditional molybdenum disulfide formulation, and one zinc carbonate and basic fuchsin formulation revealed sharp fingerprints on surfaces submerged for up to 45 days. Comparative studies on submerged glass and plastic showed that SPR, Sudan Black, fluorescent powder, black powder and silver metallic powder could all recover usable marks, with SPR standing out as most effective on transparent foil submerged for at least a week. A zinc carbonate fluorescent SPR even developed prints after simulated arson conditions involving soot deposition and temperatures up to 800 degrees Celsius.

Nanomaterials represent the review’s most technically sophisticated frontier. Nitrogen-functionalized carbon dots coated on zinc oxide nanoparticles detected fresh prints on aluminium foil, sheets, rods, iron discs, compact discs, marble and magazine paper. Cesium lead bromide perovskite nanocrystals offered optical stability and hydrophobic surfaces yielding first-, second- and third-level ridge detail. Upconversion nanomaterials such as NaYbF4:Tm enabled dual-mode visualization under near-infrared excitation, and electrodeposited gold or silver nanoparticles produced negative fingerprint images on conductive surfaces because the residue acts as an insulator. Quantum dots, including heavy-metal-free CuInS2/ZnS core/shell dots coated with N-acetylcysteine, developed prints on adhesive tape and polymer banknotes, while carbon quantum dots roughly 3 nanometres in size, synthesized from mustard seed, lemon juice, cumin seeds and mango leaves, worked under ordinary daylight. Date seed waste carbon dots emitted at approximately 495 nanometres and produced ridge patterns lasting up to 30 days.

Green synthesis threads through much of this nanoscale work. Silica nanospheres made from rice husk showed that reduced aggregation improved selectivity toward fingerprint residues; agricultural waste nanoparticles from rice husk, neem leaves, potato peel, lemon peel and orange peel achieved visibility rates reported at roughly 90 percent for rice husk, 85 percent for neem and 78 percent for potato peel; and a ZnFe2O4-reduced graphene oxide nanocomposite was synthesized using Amla fruit extract and Aloe Vera as a capping agent. A rhodamine 6G-coated nano-coal fly ash composite developed level 2 and level 3 ridge detail under daylight, and a nitrogen-doped carbon dot composite with graphitic carbon nitride achieved approximately 94 percent identifiability for fresh prints on glass under ultraviolet illumination, though contrast declined with print age.

The authors are careful to frame these findings as promising rather than settled. They note that the effectiveness and robustness of plant powders must be established more rigorously using diverse fingermark samples from varied conditions, and they call for comprehensive validation studies to establish reliability in real-world forensic scenarios before these materials are integrated into practice. Future work, they suggest, should examine how temperature, humidity and seasonal changes affect fingerprint visibility, compare new powders against traditional ones using split marks, marks of varying ages and depletion series, and determine the conditions under which non-conventional powders offer the greatest benefit. What the review makes clear is that the materials of fingerprint detection are diversifying rapidly, and that the powders of the future may come as much from the kitchen and the field as from the chemical supplier.

Subject of Research: A systematic review of eco-friendly powders and nanotechnology-based materials for latent fingerprint detection

Article Title: A systematic review of advanced materials for latent fingerprint detection from conventional powders to nanotechnology based approaches

Article References: Sintona, C. P., Jenifer, D. I., Subramaniam, S., & Obadiah, A. (2026). A systematic review of advanced materials for latent fingerprint detection from conventional powders to nanotechnology based approaches. Discover Chemical Engineering, 6(1), Article 24. https://doi.org/10.1007/s43938-026-00134-y

Image Credits: AI Generated

DOI: 10.1007/s43938-026-00134-y

Keywords: latent fingerprints, forensic science, fingerprint powders, nanomaterials, carbon dots, small particle reagent, green synthesis, turmeric, quantum dots, eco-friendly forensics, systematic, review