THE IDEA

Plumbing for drops

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Tiny channels

Usually 10 to 500 µm wide, about the width of a hair or a few cells

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Tiny volumes

Nanolitres to picolitres: a whole experiment in a fraction of a drop

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Many jobs, one chip

Mix, react, sort, grow cells and measure, all in one piece of plastic or glass

Microfluidics is the science and engineering of moving small amounts of liquid through channels thinner than a hair.

WHY SHRINK?

What you gain by going small

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Less sample A drop of blood instead of a tube, a few cells instead of a flask

Faster Short distances mean heat and molecules cross a channel in seconds

Cheaper Tiny reagent volumes, and chips that can be moulded by the million

Parallel Thousands of identical tests side by side on one chip

Control Precise flows, gradients and forces that a beaker can't give

Small isn't just smaller: it is faster, cheaper and more controllable.

IN THE WILD

You've already used microfluidics

Inkjet printheads, home pregnancy and COVID tests, glucose test strips, DNA sequencers and organ-on-a-chip research all move liquid through tiny channels.

Microfluidics is already in pockets, printers and hospitals.

A SHORT HISTORY

From silicon to soft plastic

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1979 A gas chromatograph is etched on a silicon wafer at Stanford, one of the first lab-on-a-chip devices

1990 Andreas Manz and colleagues propose the "micro total analysis system" (µTAS)

1998 George Whitesides' group popularizes soft lithography in PDMS: chips in a day, outside a cleanroom

2000 Stephen Quake's group builds PDMS valves and pumps, later packed by the thousand on one chip

2010 Donald Ingber's group at Harvard's Wyss Institute publishes a breathing lung-on-a-chip

Microfluidics was born in chip fabs, then took off once chips became cheap to make.

NEW RULES

Different forces win when things get small

Shrink a channel and its wall area per volume grows. Surface tension and viscous friction take over; gravity and inertia fade. Water stops splashing and starts behaving like slow, smooth honey.

At the microscale, surfaces and friction run the show.

UNIT 1 STUDY COMPLETE

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Ready for the Fab Challenge?

You've seen how small microfluidic channels are, what shrinking buys you, and which forces take over at that scale.