Engineered Inorganic Nanoparticles and Cosmetics: Facts, Issues, Knowledge Gaps and Challenges

Abstract

The cosmetic industry is among the first adaptors of nanotechnology through the use of engineered nanoparticles (ENPs) to enhance the performance of their products and meet the customers' needs. Recently, there have been increasing concerns from different societal stakeholders (e.g., governments, environmental activist pressure groups, scientists, general public, etc.) concerning the safety and environmental impact of ENPs used in cosmetics. This review paper seeks to address the twin concerns of the safety of cosmetics and the potential environmental impacts due to the constituent chemicals-the ENPs. The safety aspect is addressed by examining recently published scientific data on the possibility of ENPs penetrating human skin. Data indicates that although particular types of ENPs can penetrate into the skin, until now no penetration has been detected beyond the stratum corneum of the ENPs used in cosmetics. Yet, important lessons can be learned from the more recent studies that identify the characteristics of ENPs penetrating into and permeating through human skin. On the part of the environmental impact, the scientific literature has very limited or none existent specific articles addressing the environmental impacts of ENPs owing to the cosmetic products. Therefore, general ecotoxicological data on risk assessment of ENPs has been applied to ascertain if there are potential environmental impacts from cosmetics. Results include some of the first studies on the qualitative and quantitative risk assessment of ENPs from cosmetics and suggest that further research is required as the knowledge is incomplete to make definitive conclusions as is the case with skin penetration. The authors conclude that the cosmetic industry should be more transparent in its use of nanotechnology in cosmetic products to facilitate realistic risk assessments as well as scientists and pressure groups being accurate in their conclusions on the general applicability of their findings. Transparency in cosmetics needs nanotechnology, but nanotechnology in cosmetics also needs transparency

Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation

“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] In particular, cosmetic application of nanoparticles is regarded as the best technology to upgrade the performance of cosmetic products and to meet the consumer's needs. 19 For example, Popov et al showed that potential application of zinc oxide or titanium oxide nanoparticles for sunscreen has benefit to attenuate ultraviolet light by absorption and scattering. 20 Furthermore, the effect of particle size on the potential of titanium oxide nanoparticles as a sunscreen was also reported by other researchers.…”

Human health hazards of persistent inorganic and carbon nanoparticles

“…Substantial research has been done regarding hazards following from dermal exposure to coated TiO 2 nanoparticles which show at least some photocatalytic activity [7,109,[118][119][120]. This photocatalytic activity gives rise to the generation of reactive oxygen species.…”

“…Barnard [7] has suggested that the per particle hazard of TiO 2 nanoparticles linked to the generation of reactive oxygen species under irradiation by sunlight has a maximum at *33 nm. It may well be that smaller nanoparticles are more likely to breach the barrier of the stratum corneum than larger nanoparticles [120]. Following breaching of the stratum corneum, effects may be based on interaction with antigen presenting cells [117] and the molecular mechanisms discussed before, such as the generation of reactive oxygen species and interaction with cellular components such as proteins [1][2][3][96][97][98][99], and references therein].…”

“…Following breaching of the stratum corneum, effects may be based on interaction with antigen presenting cells [117] and the molecular mechanisms discussed before, such as the generation of reactive oxygen species and interaction with cellular components such as proteins [1][2][3][96][97][98][99], and references therein]. Research so far has not provided evidence of transdermal penetration of TiO 2 nanoparticles [119,120].…”

“…From the studies regarding skin exposure to nanoparticles [7,16,109,[117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133] several likely determinants of hazard emerge. These include size, chemical composition, surface characteristics, such as surface coating and surface charge, and crystalline structure.…”