EXPLORING KNOWLEDGE
OUR PHONES , OURSELVES
Molecules on your cell phone speak volumes .
BY HEATHER BUSCHMAN , PHD ’ 08
BETWEEN PHOTOS , CALENDARS AND OTHER PERSONAL INFORMATION , we generally put our entire lives into our cell phones . Yet UC San Diego researchers have discovered we leave just as much of our lives on our phones as well — at a molecular level .
In a 2015 study , the team noticed that chemical traces stay on our skin for a long time . “ And we are transferring them to just about everything we touch ,” says study leader Pieter Dorrestein , PhD , a professor in UC San Diego ’ s School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences . “ So we thought — what can left-behind skin chemistry tell us about a person ?”
Dorrestein ’ s team swabbed samples from the cell phones of volunteers , along with each person ’ s right hand . They used mass spectrometry to detect molecules , which were then compared to known structures in a reference database . Researchers used this information to construct lifestyle “ readouts ” for each phone ’ s owner — including diet , preferred hygiene products , health status and locations visited .
For instance , the phones revealed evidence of certain skin creams , hair loss treatments , eye drops and even medications like antidepressants . Food molecules included citrus , caffeine and spices . Sunscreen ingredients and mosquito repellants were detected on phones even months after they had last been used by the phone owners .
“ We could tell if a person is likely female , uses high-end cosmetics , drinks coffee , prefers beer over wine , likes spicy food — all kinds of things ,” says Amina Bouslimani , PhD , first author on the study and an assistant project scientist in Dorrestein ’ s lab .
Dorrestein and Bouslimani imagine this information could prove useful in a crime scene situation , where fingerprints or DNA aren ’ t available or aren ’ t found in a database . While molecular readouts couldn ’ t yield a one-to-one match , they could help narrow down the suspect pool .
“ Not only did we find that chemical traces stayed on our skin for a relatively long time , but we are transferring them to just about everything we touch . So we thought — what can leftbehind skin chemistry tell us about a person ?”
— PIETER DORRESTEIN , PHD
And the technique could be applied well beyond forensics . Trace molecular readouts could allow physicians to assess a patient ’ s medication regimen by monitoring metabolites on the skin . Or clinical trials could become more accurate — medication could be given only to those whose skin reveals they metabolize it well . Skin molecule read-outs may also help monitor environmental hazards , for those in high-risk workplaces or communities .
14 TRITON | SPRING 2017