Dissecting structure-function of 3-O-sulfated heparin and engineered heparan sulfates.

Heparan sulfate (HS) polysaccharides are master regulators of diverse biological processes via sulfated motifs that can recruit specific proteins. 3-O-sulfation of HS/heparin is crucial for anticoagulant activity, but despite emerging evidence for roles in many other functions, a lack of tools for deciphering structure-function relationships has hampered advances. Here, we describe an approach integrating synthesis of 3-O-sulfated standards, comprehensive HS disaccharide profiling, and cell engineering to address this deficiency. Its application revealed previously unseen differences in 3-O-sulfated profiles of clinical heparins and 3-O-sulfotransferase (HS3ST)­specific variations in cell surface HS profiles. The latter correlated with functional differences in anticoagulant activity and binding to platelet factor 4 (PF4), which underlies heparin-induced thrombocytopenia, a known side effect of heparin. Unexpectedly, cells expressing the HS3ST4 isoenzyme generated HS with potent anticoagulant activity but weak PF4 binding. The data provide new insights into 3-O-sulfate structure-function and demonstrate proof of concept for tailored cell-based synthesis of next-generation heparins.

Copper-Coated Cellulose-Based Water Filters for Virus Retention.

Despite recent efforts in modernization of water treatment facilities, the problem of access to healthy drinking water for hundreds of millions of people has still not been solved. A water filter based on Cu-coated nanofibrillated cellulose with controlled porosity was prepared by the "paper-making" method. We have optimized the proper mass and ratio of functionalized and pure nanofibrillated cellulose for the preparation of the filter. MS2 bacteriophages were used to model human pathogenic virions. We tested our filter material in batch experiments and the fixed filters in flow experiments. The fabricated Cu-coated nanofibrillated cellulose filters were characterized by scanning electron microscopy, X-ray diffraction, specific surface area measurement (Brunauer-Emmett-Teller), dynamic light scattering, and inductively coupled plasma mass spectroscopy. Our measurements proved that the fixation of cellulose nanofibers plays a significant role in the degree of virus retention and it greatly enhances the efficiency of the filtration. By using these functionalized water filters, we were able to achieve a virus retention of at least 5 magnitudes (5Log) at three different pH values: 5.0, 7.5, and 9.