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Meanwhile in the Whitesides lab

01 October 2010 - Multidisciplinary research

Whitesides_peanutbutter_research_2010.jpg With George M. Whitesides leading the h-index for chemists and the count-down to NPIC day underway, lets find out what is going on in his Harvard lab these days. It is all about miniaturization.

The stretchable antenna (Kubo, Li 2010 DOI) can be used in wearable technology and in biomedical engineering because it can be applied to any nonplanar surface. Made from a liquid metal (a gallium / indium alloy, see Galinstan) and encased in elastomeric microfluidic channels it can stretch to more than twice its original length, a new record in this particular field. The trick: use two not just one type of PDMS elastomer with variation in stiffness.

In infochemistry alphanumerical information is transmitted by chemistry (Kim et al. 2010 DOI). In one manifestation called the infofuse, a strip of nitrocellulose is ignited and as the flame-front moves forward with a speed of 3 centimeter per second it encounters metal-salt containing spots in an information pattern. By using 4 different metals, 7 distinct optical pulses are created. Problem to solve: slow down flame-front speed to allow uninterrupted 24-hour transmission of information. Solution: create a slowfuse pattern connecting information-carrying fastfuse strands. Implementation: apply slow match technology (invented 15th century), a cigarette will also do.

Wax printing is proposed as an inexpensive way to produce microfluidic patterns (channels & reservoirs) in a paper-based analytical device (PAD) based on a commercial printer , wax of course and a hot plate. The printer delivers the wax on a paper sheet and the hot plate melts the wax into the paper forming hydrophobic barriers. The aim is zero-cost medical diagnostics for for example the measurement of glucose and cholesterol levels. Another example is ELISA testing with again paper now replacing a regular microtiter plate (Cheng et al. DOI). HIV antibody test results can be scanned and quantisised using a cheap scanner or cell phone.

The Whitesides lab has also tackled the critical issue of measuring reduced-fat content in peanut butter. Mirica et al. (DOI) did so by measuring peanut butter density by magnetic levitation , a technique ordinarily used to suspend trains or lab animals. Skippy's reduced fat peanut butter clearly stands out from the regular one.

Moving on from the unusual to the bizarre: how about confining the miniature worm C. elegans (length: 1 mm) to a lab-on-a-chip (Hulme et al. DOI). The chip houses 16 worms, each in their individual chamber with a channel for delivering a constant supply of food (E. Coli) and a channel for removal of bacterial waste and progeny and for clamping down the worm. Compared to the old-fashioned petri-dish, the chip allows the continuous monitoring (a microscope) of a single worm throughout its lifetime inside its chamber. The worms live for about 9 days. The main conclusions: the longer it takes for the worm to grow to maximum volume the longer it will live and the longer the worm is able to swim above a certain stroke frequency the longer it will live. Main cause of death after the 9 days: eggs hatching inside the worm instead outside of the worm (not-so intelligent design).

More fun with Whitesides in the making it move blog.

Watch George Whitesides at TED@youtube and what exactly is simplicity?.