Tiny water sensor embedded in plant stems

Vinay Pagay holds a "lab on a chip" that measures moisture levels in soil and plants stems. The tiny sensor is much smaller and a hundred times more sensitive than current devices. (Credit: Jason Koski)

Researchers are completing soil tests on a water sensor within a fingertip-sized silicon chip and will soon test it in plants, embedding their “lab on a chip” in the stems of grape vines, for example.

They hope to mass produce the sensors for as little as $5 each.

Crop growers, wine grape and other fruit growers, food processors, and even concrete makers all benefit from water sensors for accurate, steady, and numerous moisture readings. But current sensors are large, may cost thousands of dollars, and often must be read manually.


The new chip, which is a hundred times more sensitive than current devices, is fitted with wires that can be hooked up to a card for wireless data transmission or is compatible with existing data-loggers. Chips may be left in place for years, though they may break in freezing temperatures.

Such inexpensive and accurate sensors can be strategically spaced in plants and soil for accurate measurements in agricultural fields.

For example, sophisticated vintners use precise irrigation to put regulated water stress on grapevines to create just the right grape composition for a premium cabernet or a chardonnay wine.

While growers can use the sensors to monitor water in soils for their crops, civil engineers can embed the chips in concrete to determine optimal moisture levels as the concrete cures.

“One of our goals is to try and develop something that is not only a great improvement, but also much cheaper for growers and others to use,” says Alan Lakso, professor of horticulture at Cornell University.

Cavity in a chip

The sensors make use of microfluidic technology—developed by Abraham Stroock, associate professor of chemical and biomolecular engineering—that places a tiny cavity inside the chip.

The cavity is filled with water, and then the chip may be inserted in a plant stem or in the soil where it, through a nanoporous membrane, exchanges moisture with its environment and maintains an equilibrium pressure that the chip measures.

Using chips embedded in plants or spaced across soil and linked wirelessly to computers, allows growers to “control the precise moisture of blocks of land, based on target goals,” says Vinay Pagay, who helped develop the chip as a doctoral student in Lakso’s lab.

The Cornell Center for Technology Enterprise and Commercialization is handling the intellectual property rights and patents.

Source: Cornell University