Lab Chip 15, 1708-1716 (2015)

Wearable computing technology has begun to be used in medicine to aid both training and clinical practice, but fewer scientific uses have been found elsewhere. Bingen Cortazar and colleagues in the Department of Electrical Engineering at the University of California Los Angeles have employed Google Glass as a flexible spectrophotometer for measuring the chlorophyll content of leaves in the field.

The chlorophyll content of leaves is an indicator of many aspects of both plant health and the environment. Standard assays destroy the leaf through chemical extraction, need to be performed in a lab and take time to yield results. Portable devices exist to spectrophotometrically estimate chlorophyll, but these are relatively expensive and inflexible. With the UCLA team's system a leaf is put in a 3D-printed holder and illuminated by LEDs powered by three AAA batteries. Images of the leaf taken by Google Glass worn by the experimenter are wirelessly exported to a web-based application that returns a value for chlorophyll content in around ten seconds.

Cortazar et al. calibrated their system against five species in the UCLA Botanical Gardens and could immediately estimate chlorophyll content from ten randomly chosen and unrelated species. The Google Glass system is not quite as accurate as a specialist meter but its convenience, speed and cost-effectiveness should make it an attractive alternative, especially in remote locations.