Rapid growth in nanotechnology is increasing the likelihood of engineered nanomaterials coming into contact with humans and the environment. Nanoparticles interacting with proteins, membranes, cells, DNA and organelles establish a series of nanoparticle/biological interfaces that depend on colloidal forces as well as dynamic biophysicochemical interactions. These interactions lead to the formation of protein coronas, particle wrapping, intracellular uptake and biocatalytic processes that could have biocompatible or bioadverse outcomes. For their part, the biomolecules may induce phase transformations, free energy releases, restructuring and dissolution at the nanomaterial surface. Probing these various interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings. This knowledge is important from the perspective of safe use of nanomaterials.

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We thank the reviewers for their insightful comments and we have revised the above referenced manuscript in response. In addition, we addressed each reviewer comment in an itemized fashion in the attached "Response to Reviewer Comments."We have uploaded high resolution (600 dpi minimum) TIF files for each image in the article. We have kept the images in color for the online version, but please convert these to grey-scale for the print version. We have ensured that no information is lost from the figure upon conversion.We feel we have adequately addressed all reviewer comments and hope that you will accept our review paper for publication in Energy & Environmental Science without further revision. Figure 6. Percolation Threshold was removed because it also seemed to provide superfluous detail. Section 3.2.1. Mixed Matrix MembranesSelections have been deleted due to excessive explanation of mixed matrix theory; the detail of background theory here appeared to be out of proportion with that in other sections. The important points from the deleted paragraphs have, however, been shortened and inserted into the present introduction so that major points are not lost. Also, it was re-emphasized that details about gas separation membranes were included only to show the past application and strength of these materials now being re-engineered for water treatment purposes. Section 3.3.3. Isoporous Block Copolymer MembranesSelections have been deleted, again when out of proportion detail in background explanation was found. Within the particular works cited and described, some specific details have been removed or minimized in order to highlight the most important achievement of each work. Lengthy block copolymer names have also been removed in most cases, in lieu of the type (i.e., tri-block, homopolymer) so that the individual methods described can be seen in a more general system framework. Some of the extensive deleted sections have been shortened/rewritten and inserted in the section so that significant points are not lost, but only the excess detail. DiscussionThe discussion section has been significantly lengthened and clarified. Each technology is summarized to shed light upon the benefits and hurdles of each material that led to its individual ranking in our system. Each score is justified and explained within our metric.Throughout the text, an effort was made to reduce excess detail and highlight the major hurdles achieved by each researcher cited. Primary accomplishments and future needs for each material were further emphasized throughout the body of this paper.Specific responses to the referees follows. RESPONSES TO REVIEWER COMMENTS REFEREE 1Within their extensive review the authors state that in their review "… the published literature describing … membrane technologies (i.e. nanotechnologies) is critically reviewed and discussed within the context of conventional membrane materials used in the relevant water treatment applications" and "a ranking system was developed …" (all citations from the Abstract) Yet...