An integrated digital microfluidic bioreactor for fully automatic
screening of microalgal growth and stress-induced lipid accumulation
Abstract
Algae are promising feedstock of biofuel. The screening of competent
species and proper fertilizer supply are of the most important tasks. To
accelerate this rather slow and laborious step, we developed an
integrated high-throughput digital microfluidic (DMF) system that uses
discrete droplet to serve as micro-bioreactor, encapsulating microalgal
cells. Based on the fundamental understanding of various droplet
hydrodynamics induced by the existence of different sorts of ions and
biological species, an incorporation of capacitance-based position
estimator, electrode-saving-based compensation and deterministic
splitting approach was performed to optimize the DMF bioreactor. Thus,
it enables all processes (e.g. nutrient gradient generation, algae
culturing and analyzing of growth and lipid accumulation) occurring
automatically on-chip especially in a high-fidelity way. The ability of
the system to compare different micro algal strains on chip was
investigated. Also, the Chlorella sp. were stressed by various
conditions and then growth and oil accumulation were analyzed and
compared, which demonstrated its potential as a powerful tool to
investigate microalgal lipid accumulation at significantly lower
laborites and reduced time.