Persistent, bioaccumulative, and toxic properties of liquid crystal monomers and their detection in indoor residential dust

Abstract

Liquid crystal monomers (LCMs) are used widely in liquid crystal displays (LCDs), which are dramatically changing the world due to the provision of convenient communication. However, there are essentially no published reports on the fate and/or effects of LCMs in the environment. Of 362 currently produced LCMs, 87 were identified as persistent and bioaccumulative (P&B) chemicals, which indicated that these chemicals would exhibit resistance to degradation and exhibit mobility after entering the environment. Following exposure to mixtures of LCM collected from 6 LCD devices, significant modulation of 5 genes,CYP1A4,PDK4,FGF19,LBFABP, andTHRSP, was observed in vitro. Modulation of expressions of mRNAs coding for these genes has frequently been reported for toxic (T) persistent organic pollutants (POPs). In LCM mixtures, 33 individual LCMs were identified by use of mass spectrometry and screened for in 53 samples of dust from indoor environments. LCMs were detectable in 47% of analyzed samples, and 17 of the 33 LCMs were detectable in at least 1 sample of dust. Based on chemical properties, including P&B&T of LCMs and their ubiquitous detection in dust samples, the initial screening information suggests a need for studies to determine status and trends in concentrations of LCMs in various environmental matrices as well as tissues of humans and wildlife. There is also a need for more comprehensive in vivo studies to determine toxic effects and potencies of LCMs during chronic, sublethal exposures.

Liquid crystal display screens as a source for indoor volatile organic compounds

“…S2). The detection of LCM-2 here is consistent with a recent study, which reports its presence in indoor dust (21), further confirming LCM pollution in the indoor environment.…”

“…LCDs are typically designed with large colorful display screens. Recent studies found liquid crystal monomers (LCMs), a group of synthetic organic chemicals extensively used in LCD screens with potential toxic effects on humans (21), were present in indoor dust (21,22), indicating that LCMs could be released to the indoor environment during the utilization of LCDs. Given this, it is reasonable to assume that other chemicals within LCD screens may also be released to the surrounding air and become a component of indoor VOCs.…”

Vertical Alignment of Liquid Crystals on Comb-Like Renewable Chavicol-Modified Polystyrene

“…LC molecules are readily responsive to external stimuli such as electric, magnetic fields, and surface interaction, contributing to their rheological behaviors and anisotropic physical properties [ 2 , 3 ]. Their interesting features allow them to be used in numerous applications such as electro-optical components, responsive sensors, and biological applications [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. For example, LC molecules can be used in several electronic products such as color filters [ 4 ], smart glasses [ 5 ], and display applications [ 6 , 7 ] owing to their susceptibility to electric fields.…”

“…Moreover, changes in the optical properties of LCs induced by ordering transitions under external stimuli are visible to the naked eye without additional labels or instruments. Therefore, LCs can be employed as simple monitoring sensors under external stimuli and environments such as temperature [ 8 ], gases [ 9 ], humidity [ 10 ], and indoor residential dust [ 11 ]. LC molecules are also studied for utilization as biosensors to detect the presence of proteins [ 12 , 13 ], surfactants [ 14 , 15 ], lipids [ 16 , 17 ], bacteria and virus [ 18 , 19 ].…”

“…LC molecules are also studied for utilization as biosensors to detect the presence of proteins [ 12 , 13 ], surfactants [ 14 , 15 ], lipids [ 16 , 17 ], bacteria and virus [ 18 , 19 ]. Control of the alignment behaviors of LC molecules is essential in diverse scientific and technical fields [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. LC alignment methods related to controlling the aligning abilities of LC molecules, such as pretilt angle and anchoring strength, have received attention by other researchers [ 24 , 25 , 26 , 27 ].…”