## 1 Introduction  
When nanoparticles (NPs) enter a biological fluid, such as serum, proteins and peptides adsorb onto the particle's surface, forming a nanoparticle-protein corona (NPPC) complex [1; 2; 3]. The protein cloud develops a new surface on the nanoparticle, impacting the interactions between the nanoparticle and the surrounding environment. The NPPC complex assumes the characteristics of a core-shell particle system, where the pristine particle is the \"core\" and the corona is the \"shell\" [4]. This creates a new interface between the pristine particle and the surrounding biological fluid. The formation of a protein corona has been shown to change the particle's biological effects [5; 6; 7; 8]. In addition to this change in the particle's characteristics, the adsorbed proteins have the potential to undergo conformational changes. Changes in either set of properties are especially important for nanomaterial drug products [9; 10; 11; 12; 13]. The cloak of proteins around particles in biological fluids has been shown to enhance or diminish a particle's specificity to a desired location, incite or inhibit its ability to permeate into a cell, and heighten or mitigate a biochemical response. When a protein corona forms, it is more likely to distribute and become available due to the nano-bio interface that forms around the surface of the nanoparticle. This protein cloud can change the biodistribution of the nanoparticle system depending on the biomolecular composition formed around the surface. Consequently, if the drug is reliant on specific proteins binding to the surface of the nanoparticle, then the particle could be translocated into an unintended location if non-targeted proteins form around the particle. Research efforts in the field of nanotoxicology have strived to relate (or correlate) particle properties to adverse health effects. There now exists a substantial amount of published literature on this topic; however, there is no general consensus on identifying physicochemical characteristics as predictors of toxicological responses. Many different nanoparticles, such as anatase titania, alpha-quartz silica, and gold colloids, have distinct crystal structures as opposed to amorphous materials of similar chemical composition. Notably, crystal structure has been associated with increased cytotoxicity in mammalian cell populations [14; 15; 16; 17]. Nanoparticle size has been implicated as a main driver in systemic distribution [15; 18; 19; 20]. Surface charge is related to cellular uptake mechanisms [21; 22; 23; 24]. However, for every paper published that demonstrates a direct or proportional relationship between particle properties and an induced biological affect, there are others that report a lack of association [25; 26; 27; 28]. Toxicologists who study engineered nanomaterials and nanomedicines have been interested in both complex mixtures in environmentally- and physiologically-relevant conditions in order to decipher the role of physiochemical properties in induced mechanisms of toxic action. These analytical interrogations require multi-level data collected on germane parameters. In the NPPC research space, some of these parameters include particle composition, size, and charge; corona source, composition, and mass; and NPPC activity, toxicity, and ADME properties. New data-gathering methods, such as the inclusion of mass spectrometry techniques and resultant data, produce collections of large sets that are sometimes complicated, multifaceted, and often non-comparable. Scientific data visualization is a powerful methodological tool for enabling the understanding of multi-dimensional data sets. The purpose of this study was to demonstrate the utility of data visualization as a method for identifying trends in NPPC physicochemical properties among six unique samples. Data visualization has been shown to play a crucial role by aiding scientists and practitioners to interpret underlying patterns in their data and applying the new knowledge to pose the next set of research questions [29].