## 3 Results
This enables the comprehensive comparison of the average normalized abundance of each sample and the contrast of the protein composition between each combination [45; 46; 47; 48; 49; 50]. Beginning with the three pie graphs representing samples incubated in serum-type 1, the corona from the NH\({}_{3}\)-coated particle is primarily composed of CALL_DROME (Calmodulin-related protein 97A) and MED22_CHICK (Mediator of RNA polymerase II transcription subunit 22). Similarly, the most abundant proteins in the PEG-ST1 combination are CALL_DROME and MED22_CHICK; however, these proteins are less abundant compared with NH\({}_{3}\)-ST1. These  
Figure 3: Protein abundance percent in sample. (**Top**) Each protein is represented by its own normalized abundance percentages. For example, MARCS_RAT appears in all NPPC samples, but seems to be the most abundant protein in the amine-coated AuNP with serum-type 2 shell. (**Bottom**) Each NPPC is represented with its own normalized abundance percentages. For example, all NPPC samples contain multiple proteins, but amine-coated AuNP with serum-type 2 shell seems to be the most diverse. first two pie graphs implicate a commonality among the protein corona compositions specifically for serum-type 1. However, in the COOH-ST1 sample, whereas MED22_CHICK is the most abundant protein in the sample, CALL_DROME is one of the least. This observation indicates the COOH coating (negative charged surface) may alter the protein composition to a higher degree than that of the NH\({}_{3}\) (positively charged surface) and PEG (neutrally charged surface) coatings. The three pie graphs representing samples incubated in serum-type 2 illustrate a more distributed composition for NH\({}_{3}\)- and PEG-coated nanoparticles. In both the NH\({}_{3}\)-ST2 and PEG-ST2 samples, MED22_RAT, CALL_DROME, and MED22_CHICK proteins are equally abundant. This observation indicates that these proteins may play a significant role in particle absorption in serum-type 2. However, in the COOH-ST2 sample, the CALL_DROME protein is by far the most abundant, with MARCS_RAT present in a small amount. As with the ST1-incubated samples, the COOH coating (negative charged surface) forms a different protein corona (in terms of composition) than that of the NH\({}_{3}\) (positively charged surface) and PEG (neutrally charged surface) coatings. The two most common proteins found in all coronas were CALL_DROME, (calmodulin-related protein 97A) and MARCS_CHICK (myristoylated alanine-rich C-kinase substrate). CALL_DROME regulates a range of normal cellular functions such as inflammation, metabolism, apoptosis, and immune response. The protein specifically functions as a calcium-binding messenger that modifies interactions with different target proteins like phosphatases or kinases. When calcium binds to calmodulin, a large structural change occurs. Electrophiles are needed to sequester the readily available electrons that influence the binding affinity for the positively-charged surface functionalization on the nanoparticles. MARCS is a common protein found in the cytoskeleton that performs a series of important functions including binding actin, calmodulin, and synapsin. This protein is in a class that strongly impacts cell motility, secretion, and shape. This class of proteins also participates in cell cycle regulation, neural development, and transmembrane transport. They play a part in sequestering acidic membrane phospholipids like PIP2, which is vital in protein signaling. Both proteins play important roles in the maintenance of normal cellular functions in eukaryotic cells. However, in the presence of nanoparticles, a large portion of these proteins adsorb onto particles' surfaces. When these proteins adsorb onto nanoparticles surfaces, the structure changes, and function is lost. It is important to know which proteins bind to the surface and lose structural and functional capabilities, especially when nanoparticles are used in therapeutic applications.