Aquaporins are a family of small integral membrane proteins that transport water across cell membranes in response to osmotic gradients. They facilitate fluid secretion and absorption across epithelial surfaces in kidney tubules, exocrine glands, and gastrointestinal tract. Here, we describe a novel microfluidic method to evaluate and screen for aquaporin-based transmembrane permeability in mammalian cells. A microfluidic device was designed and fabricated for the encapsulation of single mammalian and yeast cells in micron-sized droplets. For this purpose, Chinese Hamster Ovarian (CHO) cells were used. CHO cells express AQP1 (aquaporin-1) homologous to human kidney aquaporins. The cells were cultivated and exposed to different osmotic stresses to study the transmembrane water transport performance of aquaporins. Our microfluidic platform has the potential to screen for and isolate cells with best aquaporin water transport performance for a number of applications in bioengineering
