Digital microfluidics opening the way for revolution in blood sampling

August 31, 2011 By Sachiko Murakami

The days of the blood sample routine - arm out, tie tube, make a fist, find a vein and tap in -- may soon be over, thanks to a new analysis method developed at U of T by Institute of Biomaterials and Biomedical Engineering (IBBME) core professor Aaron Wheelerin which only a pinprick of blood is necessary.

Traditional methods of blood sampling requires intravenous extraction of several millilitres of blood. A phlebotomist then separates serum, which is frozen for transport or storage and later thawed and analyzed. A relatively new alternative to the traditional method uses blood samples stored as dried blood spots (DBSs).

The DBS method requires only a pinprick to extract a few microlitres of blood, which is blotted onto filter paper, where the sample, it has been found, remains stable. While DBSs have been gaining increasing popularity for the ease of sampling and storage for some time, they are still not a standard laboratory technique, and the process for using them remained laborious -- until now.

In a study published in Lab on a Chip last week, Wheeler and colleagues demonstrated the proof-of-principle that digital microfluidics could be used to automate the process of dried blood spot analysis in the case of testing for specific genetic diseases at Newborn Screening Ontario (NSO) in Ottawa. This paper is the result of a collaboration between Wheeler and NSO rsearchers.

NSO regularly screens every baby born in Ontario for genetic diseases - some 140 000 babies a year - and collects DBS samples via heelprick. Each DBS must be manually collected. Technicians must prepare the sample for testing, put it into a centrifugal tube, pipette solvent onto the sample, extract the necessary material by centrifuge, and then use robotics to conduct the chemical analysis.

Wheeler’s digital microfluidic platform automates this process. Droplets are manipulated onto the sample using electrical signals, and the material needed for analysis is extracted - all on a “lab-on-a-chip” with little manual intervention. Wheeler, the Canada Research Chair in Bioanalytical Chemistry, created the prototype for this process in the Bahen Cleanroom, a facility of the Emerging Communications Technology Institute at U of T.

Wheeler’s study quantified particular amino acids that are markers of three metabolic disorders: phenylketonuria, homocystinuria, and tyrosinemia. His next steps will be to evaluate the rest of the 28 diseases that NSO screens for.Wheeler’s innovation is indicative of the innovative tools for biomedical engineering that IBBME researchers create. “The applications for this process go far beyond newborn screening,” Wheeler stated. “Pharmaceutical companies are moving towards dried blood spot analysis, but they’re still lacking the tools to make widespread use feasible. We’ve demonstrated that digital microfluidics could be that tool. Our system is fast, robust, precise, and compatible with automation.”

While it might be a while before the days of the dreaded blood sample needle are behind us, Wheeler’s digital microfluidics method is the next step in moving to a DBS-based sampling system, said Pranesh Chakraborty, director of NSO. “This approach could save considerable costs as a result of the lower volumes of reagent required,” he affirmed. “An automated system based on this approach would also process samples faster, with higher accuracy, less risk of errors, all while freeing up time for technologists to perform other work.” Charaborty’s team provided the screening and medical perspective in this research.A patent has been filed, and Wheeler, who also holds appointments in chemistry and Banting and Best Department of Medical Research, is currently exploring commercialization options.

Provided by University of Toronto

2) Scientists take first step towards creating 'inorganic life'

September 12, 2011

Scientists at the University of Glasgow say they have taken their first tentative steps towards creating 'life' from inorganic chemicals potentially defining the new area of 'inorganic biology'.

Professor Lee Cronin, Gardiner Chair of Chemistry in the College of Science and Engineering, and his team have demonstrated a new way of making inorganic-chemical-cells or iCHELLS. Prof Cronin said: “All life on earth is based on organic biology (i.e. carbon in the form of amino acids, nucleotides, and sugars etc) but the inorganic world is considered to be inanimate.

“What we are trying do is create self-replicating, evolving inorganic cells that would essentially be alive.

You could call it inorganic biology.” The cells can be compartmentalised by creating internal membranes that control the passage of materials and energy through them, meaning several chemical processes can be isolated within the same cell – just like biological cells.

The researchers say the cells, which can also store electricity, could potentially be used in all sorts of applications in medicine, as sensors or to confine chemical reactions.

The research is part of a project by Prof Cronin to demonstrate that inorganic chemical compounds are capable of self-replicating and evolving – just as organic, biological carbon-based cells do.

The research into creating ‘inorganic life’ is in its earliest stages, but Prof Cronin believes it is entirely feasible.

Prof Cronin said: “The grand aim is to construct complex chemical cells with life-like properties that could help us understand how life emerged and also to use this approach to define a new technology based upon evolution in the material world – a kind of inorganic living technology.

“Bacteria are essentially single-cell micro-organisms made from organic chemicals, so why can’t we make micro-organisms from inorganic chemicals and allow them to evolve?

“If successful this would give us some incredible insights into evolution and show that it’s not just a biological process. It would also mean that we would have proven that non carbon-based life could exist and totally redefine our ideas of design.”

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