Fabrication and Bioseparation Studies of Adsorptive Nanofelts Made from Electrospun Cellulose and/or Carbon Nanofibers

South Dakota School Of Mines And Technology, Rapid City SD

Investigators

Abstract

CBET-0827844 Menkhaus This NSF award by the Chemical and Biological Separations program supports work by Professors Todd J. Menkhaus and Hao Fong at South Dakota School of Mines and Technology to fabricate, characterize, and evaluate an innovative adsorptive nanofelt made from electrospun cellulose and/or carbon nanofibers for the purification of large biomolecules such as proteins, viruses and DNA. Adsorptive membranes (also referred to here as adsorptive felts), have shown great promise for the downstream separation of biopharmaceutical products. Unfortunately, the binding capacity of large biomolecules on current commercial adsorptive felts is often low and can be limited by available surface area. In this project, innovative nanofelts made from cellulose and/or carbon nanofibers (with diameters in the range from 10 to 1000 nm) will be fabricated and evaluated for isolation of large biomolecules. These nanofiber nanofelts will provide a significantly elevated surface area to bed volume ratio (one to two orders of magnitude higher than conventional felts), which will offer much improved binding capacity, without compromising the desired hydrodynamic properties of high flow rates with low pressures. Nanofibers will be produced by the technique of electrospinning. Initially, preparation conditions of cellulose and carbon nanofibers will be defined, and the morphological and physical properties will be characterized. The nanofibers will then be functionalized with ionized chemical ligands, including state-of-the art three-dimensional grafting technologies, for adsorption of target molecules by ion exchange, and manufactured into nanofelts. Finally, static and dynamic adsorption capacity of a target molecule, system dispersion, and pressure profiles will be assessed for varying flow rates. Adsorption of both relatively large and small proteins, as pure solutions and as a mixture, will be evaluated to model the process and determine limiting factors of adsorption. This will provide insight into predicting optimum properties (i.e. pore size, felt thickness, and charge density) and operating conditions (i.e. flow rates) for the innovative nanofelt. From an applied perspective, results obtained in this project will provide improved technologies to reduce costs in the production of biopharmaceutical products, and will also be directly applicable to other separation fields such as environmental wastewater treatment. The multidisciplinary nature of the project will expose undergraduate and graduate students to cutting-edge technologies in both fabrications/evaluations and bioseparation applications of the electrospun adsorptive nanofelt, and prepare them for careers in the rapidly expanding nano and biotechnology industries. In addition, new problem-based learning modules in nano separation technologies will be incorporated into existing lectures/labs taught by the investigators (e.g., Design of Separation Processes, and Chemistry of Nanomaterials) to introduce important nano materials fabrication techniques and separations applications to a wide array of graduate and undergraduate students.