Paper-Based Medical Technology

Michael weilert MD synthetic biology

Recently, researchers in synthetic biology have been bringing together science, engineering and computing to understand and copy biological life to help achieve new breakthroughs.  There were recently two studies published in the journal Cell, which show how advances in synthetic biology could eventually lead to cheap, reliable diagnostics for diseases such as Ebola, which could be done quickly in the field using only drops of blood or saliva on strips of paper embedded with synthetic biology circuits.

In the first of these studies, scientists from Harvard describe how they brought lab-testing ability to pocket-sized slips of paper by embedding them with synthetic gene networks.  They also spoke about how they created various diagnostics, including strain-specific Ebola virus sensors.  Until recently, progress in synthetic biology has been limited, since scientists were only able to develop synthetic mechanisms within living cells.  However, the research team was able to create a system that allowed them to design synthetic versions of biological mechanisms outside of cells.  The researchers explain how they’ve harnessed the genetic machinery of cells, and then embedded them in the fiber matrix of paper, which can then be freeze-dried for storage and transport, allowing researchers to take synthetic biology out of the lab setting and use it anywhere.

Through their work, the researchers have developed a wide range of diagnostics and biosensors, which incorporate proteins that fluoresce and change color to show that they’re working.  Once they’ve been freeze-dried, these paper-based tools can be stored for up to a year.  To be activated, all you need to do is add water.  When used in a laboratory, this technology allows researchers to save both time and costs compared to conventional methods; certain procedures that would typically take between 2 and 3 days can now be done in as little time as 90 minutes.

For their second study, the researchers created an Ebola sensor through the “toehold switch”, a flexible and highly programmable system for controlling gene expression.  While the toehold switch was originally used to work inside living cells, the team was able to change its function to their signature freeze-dried paper method.  The toehold switch can be programmed to switch on the production of a specific protein after detecting the proper sequence of genetic code.  According to the team, it’s also possible to link multiple toehold switches to each other and create a complex circuit to carry out a series of steps, such as detecting a pathogen and then delivering the appropriate therapy.