title: Separation of Peptides with Forward Osmosis Biomimetic Membranes.
abstract: Forward osmosis (FO) membranes have gained interest in several disciplines for the rejection and concentration of various molecules. One application area for FO membranes that is becoming increasingly popular is the use of the membranes to concentrate or dilute high value compound solutions such as pharmaceuticals. It is crucial in such settings to control the transport over the membrane to avoid losses of valuable compounds, but little is known about the rejection and transport mechanisms of larger biomolecules with often flexible conformations. In this study, transport of two chemically similar peptides with molecular weight (Mw) of 375 and 692 Da across a thin film composite Aquaporin Inside™ Membrane (AIM) FO membrane was investigated. Despite the relative large size, both peptides were able to permeate the dense active layer of the AIM membrane and the transport mechanism was determined to be diffusion-based. Interestingly, the membrane permeability increased 3.65 times for the 692 Da peptide (1.39 × 10-12m²·s-1) compared to the 375 Da peptide (0.38 × 10-12m²·s-1). This increase thus occurs for an 85% increase in Mw but only for a 34% increase in peptide radius of gyration (Rg) as determined from molecular dynamics (MD) simulations. This suggests thatRgis a strong influencing factor for membrane permeability. Thus, an increasedRgreflects the larger peptide chains ability to sample a larger conformational space when interacting with the nanostructured active layer increasing the likelihood for permeation.
authors.affiliation: Department of Environmental Engineering, Technical university of Denmark, Kongens Lyngby 2800, Denmark. nbaj@env.dtu.dk.
authors.forename: Niada
authors.initials: N
authors.lastname: Bajraktari
authors.affiliation: Department of Chemistry and Bioscience, Aalborg University, Copenhagen 2450, Denmark. htm@bio.aau.dk.
authors.forename: Henrik T
authors.initials: HT
authors.lastname: Madsen
authors.affiliation: Department of Environmental Engineering, Technical university of Denmark, Kongens Lyngby 2800, Denmark. nano.mathias@gmail.com.
authors.forename: Mathias F
authors.initials: MF
authors.lastname: Gruber
authors.affiliation: Department of Environmental Engineering, Technical university of Denmark, Kongens Lyngby 2800, Denmark. sigut@env.dtu.dk.
authors.forename: Sigurd
authors.initials: S
authors.lastname: Truelsen
authors.affiliation: Department of Pharmacy, University of Copenhagen, Copenhagen 2100, Denmark. ellu57@gmail.com.
authors.forename: Elzbieta L
authors.initials: EL
authors.lastname: Jensen
authors.affiliation: Department of Pharmacy, University of Copenhagen, Copenhagen 2100, Denmark. henrik.jensen@sund.ku.dk.
authors.forename: Henrik
authors.initials: H
authors.lastname: Jensen
authors.affiliation: Department of Environmental Engineering, Technical university of Denmark, Kongens Lyngby 2800, Denmark. clhe@env.dtu.dk.|Department of Chemical Technology, University of Maribor, Maribor 2000, Slovenia. clhe@env.dtu.dk.
authors.forename: Claus
authors.initials: C
authors.lastname: Hélix-Nielsen
keywords: biomimetic; forward osmosis; peptides; rejection