Amino acids are the basic “building blocks” of peptides and proteins and play important roles in the physiological processes of all species. In this study, we simulated the Raman spectrum of Glycine, Tyrosine and Phenylalanine using General Atomic and Molecular Electronic Structure System (GAMESS) and Gaussian, two computational codes that perform calculations of electronic and vibrational properties of molecules. Through our work, strong bands with N-H and O-H bonds and with benzyl ring were pinpointed and identified. Our work presents insights into the importance of intermolecular bonding of amino acids in the life and physiological processes, including metabolism, signal transduction, and neurotransmission etc.
Raman spectroscopy is commonly used in chemistry and biology. As vibrational information is specific to the chemical bonds, Raman spectroscopy provides fingerprints to identify the type of molecules in the sample. In this paper, we simulate the Raman spectrum of organic and inorganic materials by GAMESS and GAUSSIAN on our high- performance cluster. By using MPI (message passing interface), we are able to run the codes in parallel. From our simulations, we will set up a database that allows search algorithms to quickly identify N-H and O-H bonds in different materials.
Giant unilamellar vesicles (GUVs) are well-established model systems for studying lipid packing and membrane dynamics. With sizes larger than 1 μm, GUVs are easily observable using optical microscopy. Gold nanoparticles (AuNPs) are well known for their biocompatibility and such biomedical applications in drug and gene delivery as well as medical diagnostics and therapeutics. On the other hand, silver nanoparticles (AgNPs) have long been known for their potent antimicrobial and anti-inflammatory effects for such applications as wound dressing and biomedical implants. In this work, we employed the dark-field microscopy (CytoViva Inc.) to study the interactions between AuNPs/AgNPs and GUVs, respectively. The GUVs used in this study were prepared with 1,2 dimyristoyl-sn-glycero-3-phosphocholine (DMPC) as well as cholesterol (chol) at various mol% concentrations (0, 10, 20, 30, 40%). The electroformed GUVs were allowed to incubate with gold or silver nanoparticles of various sizes (between 10 and 100 nm) for 2 hrs before microscopic examination. The experiment has shown that the size of nanoparticles is a critical factor that determines the penetration rate. In addition, the membrane rigidity increases with the molar concentration of cholesterol hence making the NP penetration more difficult. Comparative studies have been made between AuNPs and AgNPs in regard to NP penetration and loading rate as well as the morphological changes induced in GUVs. This work aims to better understand the mechanisms of AuNP/AgNP and membrane interactions for their respective future applications in nanomedicine and nanotechnology.