Diarylethene Photoswitches and 3D Printing to Fabricate Rewearable Colorimetric UV Sensors for Sun Protection

Abstract

damage has been done. The association between a range of skin and eye diseases and exposure to UV light is well established. [1] Despite this knowledge leading to public health education campaigns, the improvement and increased use of broad spectrum sunscreens, sun-related skin cancers continue to be a major health concern. [2,3] Clearly, prevention is better than a cure, and so new innovations are needed to improve people's awareness of their risk when enjoying the sun.Solar UV radiation is typically classified into three classes: UV-A (315-400 nm), UV-B (280-315 nm), and UV-C (100-280 nm). UV-C radiation (and high energy UV-B <300 nm), while being the highest in energy, is of little concern in a sun protection setting on the Earth's surface, as radiation in this spectrum is effectively filtered by the ozone layer (Figure 1). Typically it is the UV-B range that is considered the highest risk for disease, as light in this spectral range can affect direct damage to DNA. [4,5] UV-A is typically regarded as capable of damaging connective tissue and blood vessels in deeper dermal layers and is therefore responsible for ageing, but there is a growing body of evidence for the causal link between UV-A radiation and cancer through indirect damage by reactive oxygen species (ROS). [1,4,5] As such, protection from light across the UV spectrum with broad spectrum sunscreens and UV protective clothing has become increasingly important.Although the link between sun exposure and cancer risk has been established, the role of human behavior in mitigating this risk is critical. [3] Broad spectrum sunscreen is capable of protecting from UV radiation, however, appropriate application is often lacking, and can lead to increased exposure time (and overall dose) in sun-seeking individuals. [7] Conversely, while the deleterious link between UV light and disease is well communicated in the community, there is also a need for UV-B light for the metabolism of the essential vitamin D 3 . [8] Vitamin D deficiency can lead to a range of medical conditions, and so a small, sub-damaging dose of UV exposure is necessary for a healthy life. It is clear there are significant challenges in measuring a person's exposure to UV light, providing an estimation of their level of risk, to enable educated decisions about their sun-seeking behavior.A wide range of laboratory prototypes and commercial wearable UV sensors have been developed that aim to improve sun protection. [9,10] They can be broadly divided into two classes, Despite education campaigns linking sun overexposure and skin cancer, it remains one of the leading preventable cancer diagnoses. Skin cancer risk is correlated with overexposure to UV light in sunlight and can be prevented by avoiding exposure. While sun protection can be achieved using sunscreen and clothing, people must be made aware of their risk to facilitate behavior change. Herein, new rewearable UV sensors which overcome the single-use limitations of other products are presented. These sensors utilize diarylethene photoswitch...

Recyclable soft photonic crystal film with overall improved circularly polarized luminescence

“…Considering that functional materials based on molecular isomer switches can achieve light-driven reversible changes in external properties such as color 39 , 40 , shape 41 and fluorescence 42 , 43 , which show great potential in the fields of sensors 44 – 46 , actuators 47 , 48 , soft systems 49 and anticounterfeiting systems 50 , 51 , herein, an ACQ effect molecule, photofluorochromic SP 52 – 54 , was used as a representative material for constructing a switchable CPL-active SPC film. SP can convert to the colored and fluorescent merocyanine (MC) isomer upon irradiation with UV light and revert to the colorless SP isomer upon heating or visible light irradiation (Fig.…”

Light‐Responsive Nanoassemblies: Advancing Biomedical Innovation

“…This is because the former can not only replicate the complexity of the microenvironment but also mimic multi-organ interactions. [211,212] Despite the multiple challenges faced in addressing the complex interaction of multiple organs, we envision its potential to model a multi-organ system to achieve "human-on-a-chip" as a replacement to the current in vitro testing method. As of now, the more urgent matter on hand is the manufacturing and implementation cost of the system.…”

“…In particular, UV irradiation inclusive of UVA, UVB, and UVC is among the most potent as they can cause DNA, protein, and lipid damage. [210,211] It is therefore of paramount importance to ensure both the patients and healthcare workers comply with the established exposure threshold limit. Besides, this also urges the exploration of alternative safer light sources and the development of highly efficient light-responsive nanoassemblies that require lower activation intensity to achieve comparable therapeutic performance.…”

Emerging Additive Manufacturing Methods for Wearable Sensors: Opportunities to Expand Access to Personalized Health Monitoring

“…Adapted with permission. [ 191 ] Copyright 2023, Wiley‐VCH. D) A multi‐material 3D printed device containing conductive parts.…”

“…[ 36 ] Recent process innovations enabling printing systems with high‐speed, multi‐nozzle arrays can substantially reduce manufacturing time, increasing throughput and thus decreasing overall unit cost. [ 198–200 ] Such efforts are essential to enabling new classes of functional printable materials, as diverse analyte detection necessitates tailoring printed components with included functional materials [ 191 ] (Figure 5C). Other promising innovations lie in process advancements that expand the capabilities of multi‐material printing [ 192 ] (Figure 5D) that expand the range of printable, functional components as well as print processes that enable the fabrication of multiscale, microarchitected composites with programmed features (e.g., controlling architecture from nanoscale to macroscale).…”