The safety of tattoo inks: Possible options for a common regulatory framework

Tattoo Ink Metal Nanoparticles: Assessment of Toxicity In Vitro and with a Novel Human Ex Vivo Model

Tattoo inks contain varying amounts of metal nanoparticles (NPs) < 100 nm that, due to their unique physicochemical properties, may have specific biological uptake and cause skin or systemic toxicities. The toxic effects of certified reference standards of metal NPs and samples of commercially available tattoo inks were investigated using an in vitro system and a novel human ex vivo model. In vitro toxicity was evaluated using vitality assays on human skin cells (HaCaT cell line, primary fibroblasts, and keratinocytes). No toxicity was observed for Al2O3, Cr2O3, Fe2O3, and TiO2 NPs, whereas CuO NPs showed dose-dependent toxicity on HaCaT and primary fibroblasts. Fibroblasts and keratinocytes were also sensitive to high concentrations of ZnO NPs. Reference standards and ink samples were then injected ex vivo into human skin explants using tattoo needles. Histological analysis showed pigment distribution deep in the dermis and close to dermal vessels, suggesting possible systemic diffusion. The presence of an inflammatory infiltrate was also observed. Immunohistochemical analysis showed increased apoptosis and expression of the inflammatory cytokine interleukin-8 in explants specifically tattooed with the reference standard or red ink. Taken together, the results suggest that the tattooing technique leads to exposure to toxic metal NPs and skin damage.

Ocular and Periocular Tattoo Adverse Effects: A Review

BACKGROUND

Ocular and periocular tattoos, involving ink application to the eyeball or surrounding skin, have gained popularity as forms of self-expression. However, this trend raises significant concerns about potential complications that can adversely affect ocular health and esthetics. Awareness of these risks is crucial for both patients and practitioners.

METHODS

A comprehensive literature review was conducted, focusing on studies discussing complications related to ocular and periocular tattooing. Relevant studies were identified through the MEDLINE, PubMed, and Ovid databases. The reviewed papers were evaluated based on study design, including blinding, sample size, control use, randomization, and objective endpoints, and classified according to the Oxford Center for Evidence-Based Medicine evidence hierarchy.

RESULTS

The review identified a wide range of complications, including immediate issues like bleeding, infections (conjunctivitis, endophthalmitis), and allergic reactions. Delayed reactions included granuloma formation, often requiring further treatment. The most serious risk identified was potential visual impairment due to improper technique or ink placement.

CONCLUSIONS

With the growing trend in ocular and periocular tattooing, there is an urgent need for increased awareness of associated risks. It is crucial to ensure that only qualified professionals perform these procedures, emphasizing the importance of understanding ocular anatomy. Developing strict regulatory guidelines and prioritizing research on the long-term effects of these tattoos are essential for patient safety. A collaborative approach among healthcare providers, regulatory bodies, and educational institutions is needed to mitigate risks and promote best practices in cosmetic tattooing.

Detection of anaerobic and aerobic bacteria from commercial tattoo and permanent makeup inks

Tattooing and use of permanent makeup (PMU) have dramatically increased over the last decade, with a concomitant increase in ink-related infections. Studies have shown evidence that commercial tattoo and PMU inks are frequently contaminated with pathogenic microorganisms. Considering that tattoo inks are placed into the dermal layer of the skin where anaerobic bacteria can thrive and cause infections in low-oxygen environments, the prevalence of anaerobic and aerobic bacteria should be assessed in tattoo and PMU inks. In this study, we tested 75 tattoo and PMU inks using the analytical methods described in the FDA Bacteriological Analytical Manual Chapter 23 for the detection of both aerobic and anaerobic bacterial contamination, followed by 16S rRNA gene sequencing for microbial identification. Of 75 ink samples, we found 26 contaminated samples with 34 bacterial isolates taxonomically classified into 14 genera and 22 species. Among the 34 bacterial isolates, 19 were identified as possibly pathogenic bacterial strains. Two species, namely Cutibacterium acnes (four strains) and Staphylococcus epidermidis (two strains) were isolated under anaerobic conditions. Two possibly pathogenic bacterial strains, Staphylococcus saprophyticus and C. acnes, were isolated together from the same ink samples (n = 2), indicating that tattoo and PMU inks can contain both aerobic (S. saprophyticus) and anaerobic bacteria (C. acnes). No significant association was found between sterility claims on the ink label and the absence of bacterial contamination. The results indicate that tattoo and PMU inks can also contain anaerobic bacteria.

IMPORTANCE

The rising popularity of tattooing and permanent makeup (PMU) has led to increased reports of ink-related infections. This study is the first to investigate the presence of both aerobic and anaerobic bacteria in commercial tattoo and PMU inks under aerobic and anaerobic conditions. Our findings reveal that unopened and sealed tattoo inks can harbor anaerobic bacteria, known to thrive in low-oxygen environments, such as the dermal layer of the skin, alongside aerobic bacteria. This suggests that contaminated tattoo inks could be a source of infection from both types of bacteria. The results emphasize the importance of monitoring these products for both aerobic and anaerobic bacteria, including possibly pathogenic microorganisms.

Feeding Next-Generation Nanomedicines to Europe: Regulatory and Quality Challenges

New and innovative nanomedicines have been developed and marketed over the past half-century, revolutionizing the prognosis of many human diseases. Although a univocal regulatory definition is not yet available worldwide, the term "nanomedicines" generally identifies medicinal products that use nanotechnology in their design or production. Due to the intrinsic high structural complexity of these products, the scientific and regulatory communities are reflecting on how to revise the regulatory framework to provide a more appropriate benefit/risk balance to authorize them on the market, considering the impact of their peculiar physicochemical features in the evaluation of efficacy and safety patterns. Herein, a critical perspective is provided on the current open issues regarding regulatory qualification and physicochemical characterization of nanosystems considering the current European regulatory framework on nanomedicine products. Practicable paths for improving their quality assurance and predicting their fate in vivo are also argued. Strengthening the multilevel alliance among academic institutions, industrial stakeholders, and regulatory authorities seems strategic to support innovation by standard approaches (e.g., qualification, characterization, risk assessment), and to expand current knowledge, also benefiting from the new opportunities offered by artificial intelligence and digitization in predictive modelling of the impact of nanomedicine characteristics on their fate in vivo.

Potential chemical risks from tattoos and their relevance to military health policy in the United States

We summarize and consolidate disparate sources of information about the practice of tattooing and its potential implications for military population health and policy. Each branch of the United States military has policies about tattoos for service members, but these have varied over time and do not cover health protection. The number of veterans receiving disability payments and the cost of those payments has been rising over time; the broad category of skin conditions accounts for 11% of disability claims. Any additional factor, such as tattoos that may increase the occurrence of adverse skin reactions, can substantially impact veteran benefit expenses and budgets. This may be a consideration for the military as it evaluates its policies related to tattoos among service members.

Tattoo inks are toxicological risks to human health: A systematic review of its ingredients, fate inside skin, toxicity due to polycyclic aromatic hydrocarbons, primary aromatic amines, metals, and overview of regulatory frameworks

Today, tattooing has become very popular among people all over the world. Tattooists, with the help of tiny needles, place tattoo ink inside the skin surface and unintentionally introduce a large number of unknown ingredients. These ingredients include polycyclic aromatic hydrocarbons (PAHs), heavy metals, and primary aromatic amines (PAAs), which are either unintentionally introduced along with the ink or produced inside the skin by different types of processes for example cleavage, metabolism and photodecomposition. These could pose toxicological risks to human health, if present beyond permissible limits. PAH such as Benzo(a)pyrene is present in carbon black ink. PAAs could be formed inside the skin as a result of reductive cleavage of organic azo dyes. They are reported to be highly carcinogenic by environmental protection agencies. Heavy metals, namely, cadmium, lead, mercury, antimony, beryllium, and arsenic are responsible for cancer, neurodegenerative diseases, cardiovascular, gastrointestinal, lungs, kidneys, liver, endocrine, and bone diseases. Mercury, cobalt sulphate, other soluble cobalt salts, and carbon black are in Group 2B, which means they may cause cancer in humans. Cadmium and compounds of cadmium, on the other hand, are in Group 1 (carcinogenic to humans). The present article addresses the various ingredients of tattoo inks, their metabolic fate inside human skin and unintentionally added impurities that could pose toxicological risk to human health. Public awareness and regulations that are warranted to be implemented globally for improving the safety of tattooing.

Tattoo Inks for Optical Biosensing in Interstitial Fluid

The persistence of traditional tattoo inks presents an advantage for continuous and long-term health monitoring in point of care devices. The replacement of tattoo pigments with optical biosensors aims a promising alternative for monitoring blood biomarkers. Tattoo inks functionalization enables the control of interstitial biomarkers with correlated concentrations in plasma, to diagnose diseases, evaluate progression, and prevent complications associated with physio pathological disorders or medication mismatches. The specific biomarkers in interstitial fluid provide a new source of information, especially for skin diseases. The study of tattoo inks displays insufficient regulation in their composition, a lack of reports of the related complications, and a need for further studies on their degradation kinetics. This review focuses on tattoo optical biosensors for monitoring dermal interstitial biomarkers and discusses the clinical advantages and main challenges for in vivo implantation. Tattoo functionalization provides a minimally invasive, reversible, biocompatible, real-time sensing with long-term permanence and multiplexing capabilities for the control, diagnosis, and prevention of illness; it enables self-controlling management by the patient, but also the possibility of sending the records to the doctor.

Quantitative analysis of metals and metal-based nano- and submicron-particles in tattoo inks

Exposure to metals and metal-based nano- (NPs, 1-100 nm) and submicron-particles (SPs, 0.1-1 μm) contained in tattoo inks and related health safety is currently receiving a great deal of interest. Twenty inks of different brands and colours were sampled in Italy in 2019. The SemiQuant Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis allowed quantifying the concentration of 18 metals (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Sn, Ti, Zn) in inks. The Single Particle ICP-MS was used to detect the diameters and concentration of NPs and SPs of 9 metals (Al, Co, Cr, Cu, Hg, Ni, Pb, Ti and Zn). Concentration of metals in tattoo inks were below the recommended concentrations reported in the Resolution ResAP (2008)1 indicating ink production have shifted to purer materials and best manufacturing practices. Regarding particles, Al was found at nano- (62-80 nm) and submicron-sizes (105-140 nm). Sizes of Cr, Cu, Pb and Zn were in the intervals 42-62 nm, 44-96 nm, 26-28 nm and 26-59 nm, respectively. Titanium was at submicron-diameters (166-383 nm). In addition, Cr and Ti particles accounted for the 47% and 80% of their total concentration, respectively. Tattooing practice exposed humans to metal-based NPs and SPs and the presence of a combination of particles of different metals and/or their dynamics (e.g., dissolution) may change their bioavailability and toxicity.