Across societies, there’s a certain cultural cachet to having the ‘ideal’ skin. Though what we think of as an appealing tone or texture can depend on where we come from, many beauty-conscious people keep an eye on a common group of factors known to affect the quality of their skin, ranging from sun exposure to dietary choices.
As more of us live in urban environments, however, there’s another factor that can take a noticeable toll on skin quality: air pollution. Often consisting of particulate matter (PM)—a blend of microscopic solids like soot, or liquid droplets of various chemicals—air pollutants have been reportedly linked to various skin disorders, including changes in skin pigmentation.
Part of the problem is that PM can be tiny enough to seep under the skin through hair follicles or sweat ducts. PM also often includes polycyclic aromatic hydrocarbons (PAHs), which can trigger our skin cells to produce reactive oxygen species: chemicals that accelerate features of ageing skin, and alter the pattern of pigments it creates.
Many mysteries remain about the precise mechanisms by which PAHs trigger the molecular pathways of pigmentation. Treading through this unexplored realm, A*STAR Graduate Scholar Rachel Phua is among a community of young researchers working to answer some of the basic questions involved.
In this interview with A*STAR Research, Phua reviews her ‘skin-deep’ fascination with the human body’s largest organ and its impact on her scientific journey, and provides us with a glimpse into her current work and findings to date.
Q: As a self-described ‘biology home-girl’, what drives your passion for the subject?
My fascination with science began in adolescence, driven by a curiosity about natural phenomena. Watching science programmes inspired me to delve into questions about the world, and ultimately led me to choose the science stream in school. I thrived in laboratories, relishing in running experiments and finding satisfaction in observable results.
What fuels my passion for biology is the scientist's innate drive to comprehend and solve mysteries. The knowledge of an unknown waiting to be discovered motivates me, instigating a perpetual curiosity that keeps me dedicated to the field.
Q: Tell us about your journey as a young researcher.
I earned my bachelor's degree in biomedical science from the National University of Singapore. During that period, I immersed myself in diverse research projects, such as designing a synthetic eukaryotic genome (Sc 2.0) and investigating toxins in the venom of the green mamba snake. These experiences not only ignited a love for research in me, but also taught me the value of perseverance amid challenges and setbacks.
After graduating, I sought to refine my skills in molecular biology and joined Carlos Clavel's team at A*STAR Skin Research Labs (A*SRL), which is a member of the Skin Research Institute of Singapore (SRIS). My work there focused on an industry project that explored the impact of air pollution on skin pigmentation.
Upon its completion, I found myself still grappling with lingering questions about the underlying mechanisms involved in how our skin reacts to pollutants. To answer them, I decided to pursue a PhD at Nanyang Technological University’s Lee Kong Chian School of Medicine, with the support of the A*STAR Graduate Scholarship.
Q: How has A*STAR supported your scientific journey?
Applying for the A*STAR Graduate Scholarship felt instinctive; it offered me the opportunity to collaborate with a dynamic and innovative team dedicated to advancing science and pioneering groundbreaking technologies. A*STAR's unique approach in bridging academia and industry resonated with me. It provided me with opportunities to attend conferences, interact with industry professionals and foster meaningful connections in the field.
Q: Why examine the links between skin and air pollution?
You could say my initial interest in this field was thanks to a ‘skin-deep’ fascination. Our skin often holds immense societal significance as it’s closely tied to the concept of beauty, particularly as it relates to women. It’s also the largest organ of the human body and the first line of defence against environmental insults—like chemical and physical pollutants in the air around us.
While many acknowledge that air pollution can darken the skin and are willing to invest in skincare products and measures to counter this effect, the precise molecular mechanisms behind this process remain largely elusive; there are significant research gaps in this area. In my view, it’s crucial to obtain a fundamental understanding of how air pollutants affect pigment production and transfer cycles before we can identify the optimal compounds to block or reverse this effect.
My ultimate goal is to better understand these molecular mechanisms and potentially identify their related optimal compounds, which will hopefully add valuable insights to the field of skincare research.
Q: Can you tell us about your current work at A*STAR?
As part of my PhD studies, I am exploring how polycyclic aromatic hydrocarbons (PAH), a major component of PM, affect our skin’s pigmentation. Employing a combination of 2D, 3D in vitro and in vivo methods, as well as downstream assays, I am rigorously testing my hypothesis, which is that PAH causes an increase in pigmentation.
Our preliminary data not only indicates a direct correlation between PAH and pigmentation, but also hints at a novel molecular mechanism that hasn’t been previously studied. Our work is progressively unveiling more details about it, which is a development I find very exciting.
Earlier this year, my colleagues and I also achieved a significant milestone by publishing a manuscript in STAR Protocols, where we discussed our work on the in vitro quantification of pigment production and transfer in 2D co-cultures and 3D skin organotypic models. This project was a long-standing endeavour fuelled by our determination to find an unbiased method for quantifying pigment production and transfer.
Q: What advice would you share with young STEM researchers?
When applying for my PhD degree, a senior student in the lab emphasised the importance of inherent passion and dedication to your subject. This passion has been my driving force during challenging times. I credit much of my progress to the supervision and support of my mentor, who not only encouraged my active participation in talks, seminars, and conferences but also facilitated engaging discussions with fellow professionals.
I firmly believe that aspiring young talents in STEM fields should seek a supportive and nurturing lab environment. The invaluable assistance from my seniors has been pivotal throughout my journey; they continue to support me every day. I am profoundly grateful to them for contributing to my research journey. I hope that everyone pursuing an academic degree finds mentors and peers like them.