Media Releases

Happy face tattoo does serious work

November 30, 2012

TORONTO, ON — A med­ical sen­sor that attach­es to the skin like a tem­po­rary tat­too could make it eas­i­er for doc­tors to detect meta­bol­ic prob­lems in patients and for coach­es to fine-tune ath­letes’ train­ing rou­tines. And the entire sen­sor comes in a thin, flex­i­ble pack­age shaped like a smi­ley face.

“We want­ed a design that could con­ceal the elec­trodes,” says Vin­ci Hung, a PhD can­di­date in the Depart­ment of Phys­i­cal & Envi­ron­men­tal Sci­ences at UTSC, who helped cre­ate the new sen­sor. “We also want­ed to show­case the vari­ety of designs that can be accom­plished with this fab­ri­ca­tion tech­nique.”

The new tat­too-based sol­id-con­tact ion-selec­tive elec­trode (ISE) is made using stan­dard screen print­ing tech­niques and com­mer­cial­ly avail­able trans­fer tat­too paper, the same kind of paper that usu­al­ly car­ries tat­toos of Spi­der­man or Dis­ney princess­es. In the case of the sen­sor, the “eyes” func­tion as the work­ing and ref­er­ence elec­trodes, and the “ears” are con­tacts for a mea­sure­ment device to con­nect to.

Hung con­tributed to the work while in the lab of Joseph Wang, a dis­tin­guished pro­fes­sor at the Uni­ver­si­ty of Cal­i­for­nia San Diego. She worked there for six months ear­li­er this year under the Michael Smith For­eign Study sup­ple­ment from NSERC.

“It was a won­der­ful oppor­tu­ni­ty,” Hung said. She worked direct­ly with Wang, who is well-known for his inno­va­tions in the field of nano­engi­neer­ing and is a pio­neer in biosen­sor tech­nol­o­gy.

The sen­sor she helped make can detect changes in the skin’s pH lev­els in response to meta­bol­ic stress from exer­tion. Sim­i­lar devices, called ion-selec­tive elec­trodes (ISEs), are already used by med­ical researchers and ath­let­ic train­ers. They can give clues to under­ly­ing meta­bol­ic dis­eases such as Addison’s dis­ease, or sim­ply sig­nal whether an ath­lete is fatigued or dehy­drat­ed dur­ing train­ing. The devices are also use­ful in the cos­met­ics indus­try for mon­i­tor­ing skin secre­tions.

But exist­ing devices can be bulky, or hard to keep adhered to sweat­ing skin. The new tat­too-based sen­sor stayed in place dur­ing tests, and con­tin­ued to work even when the peo­ple wear­ing them were exer­cis­ing and sweat­ing exten­sive­ly. The tat­toos were applied in a sim­i­lar way to reg­u­lar trans­fer tat­toos, right down to using a paper tow­el soaked in warm water to remove the base paper.

To make the sen­sors, Hung and her col­leagues used a stan­dard screen print­er to lay down con­sec­u­tive lay­ers of sil­ver, car­bon fiber-mod­i­fied car­bon and insu­la­tor inks, fol­lowed by elec­tropoly­mer­iza­tion of ani­line to com­plete the sens­ing sur­face.

By using dif­fer­ent sens­ing mate­ri­als, the tat­toos can also be mod­i­fied to detect oth­er com­po­nents of sweat, such as sodi­um, potas­si­um or mag­ne­sium, all of which are of poten­tial inter­est to researchers in med­i­cine and cos­me­tol­ogy.

Hung’s PhD super­vi­sor at UTSC and a co-author of the paper is Kagan Ker­man, assis­tant pro­fes­sor of bio-ana­lyt­i­cal chem­istry. An arti­cle describ­ing the work has been accept­ed for pub­li­ca­tion in the Roy­al Soci­ety of Chemistry’s jour­nal, Ana­lyst, and is avail­able on the journal’s web­site at (DOI: 10.1039/C2AN36422K).


For more infor­ma­tion, please con­tact:

Kurt Klein­er
Man­ag­ing Edi­tor, Online Com­mu­ni­ca­tions
Com­mu­ni­ca­tions & Pub­lic Affairs
Uni­ver­si­ty of Toron­to Scar­bor­ough
Phone: 416–287-7008