Bilayer graphene oxide membranes for a wearable hemodialyzer

2D nanomaterials have long been considered for development of ultra-high throughput membranes, due to their atomically thin nature and high mechanical strength. However, current processes have yet to yield a viable membrane for practical applications due to the lack of scalability and substantially improved performance over existing membranes. Herein, a graphene oxide (GO) bilayer membrane with a permeability of 1562 mL/hr.mmHg.m2, two orders of magnitude higher than existing nanofiltration membranes, and a tight molecular weight cut-off (MWCO) is presented. To build such a membrane, we have developed a new process involving self-assembly and optimization of GO nanoplatelets physicochemical properties. The process produced a highly organized mosaic of nanoplatelets enabling ultra-high permeability and selectivity with only three layers of GO. Performance of the membrane has been evaluated in a simulated hemodialysis application, where it presents a great value proposition. The membrane has a precise molecular cut-off size of 5 nm, adjusted using a molecular interlinker, designed to prevent loss of critical blood proteins. Urea, cytochrome-c, and albumin are used as representative test molecules. Urea and cytochrome-c sieving coefficients of 0.5 and 0.4 were achieved under physiological pressure conditions, while retaining 99% of albumin. Hemolysis, complement activation, and coagulation studies exhibit a performance on par or superior to the existing hemodialyzer materials.