Recognition study based on the nano-membrane interfacial interactions and targeting nanocarrier based on the nano-protein interactions

Nanoparticles (NPs) are tiny materials ranging from 1 to 100 nm. NPs possess unique physical and chemical properties due to their high surface area and nanoscale size. Their reactivity, toughness, and other properties are also dependent on their unique size, shape, and structure. Due to these characteristics, they are brought around vast and heterogeneous NP-based platforms for diagnosing and treating many diseases. While we are increasingly exposed to nanomaterials every day, the exploitation of their full potential, especially in the biomedical field, is far from realized. When NPs are administered into the biological environment of the systemic circulation, a dynamic interplay occurs between the circulating proteins and the NPs. The set of proteins that bind to the NP surface is referred to as the protein corona (PC). PC assembly confers NPs with a new biological identity that determines their colloidal stability, biodistribution, interactions, toxicity, and clearance. The cell membrane is the first barrier for NPs to surmount. These NP-membrane interfacial interactions between NPs and cell membranes are the initial step that plays an essential role in the physiological effects of NPs. However, it is still unclear what kind of cellular responses are induced by NPs only based on the NP-membrane interfacial interactions and how the interaction between NPs and receptors induces signaling pathways and endocytosis. This thesis studied the cellular responses based on the NP-membrane interfacial interactions. A huge dysregulated phosphorylation level was induced, while no significant difference was identified on the protein level. It indicates a quick cellular response was generated upon the post-translational modifications once cells received information from the interactions between NP-PCs and receptors. Proteins containing dysregulated phosphorylation are mainly involved in pathways such as signaling transduction and RNA metabolism. The proteins containing dysregulated modifications in membranal tyrosine phosphoproteomics and ubiquitomics also proved the signaling transduction pathway regulation. The down-regulation of these modifications (cell level and subcellular level) is the primary trend that is possibly helpful to self-protection from the outer stimulations. A nanoscale bionanosynapse structure was proposed to receive signals from NP-PCs, systematically manage them, and then deliver them. This hypothesized bionanosynapse was captured by crosslinking method and verified by microscopical tools. Protein and RNA are two main components. And both have a differential distribution at the inner sections of bionanosynapse. Proteins related to RNA granules are one major component in the protein pool, probably involved in RNA metabolism. PC offers a potential way to design targeting nanocarriers for drug delivery in which controlling protein and protein corona can mask NP surface and perform desirable biological functions. ApoE can be frequently identified in the PC layer as it is highly concentrated in the blood. In addition, ApoE is a proper choice for designing a targeting nanocarrier because of its biological importance and simple structure. A sequence of ApoE from 1 to 183 was kept from the original ApoE sequence but with several modifications. Protein directionality decides optimal binding sites and protein function flexibility and availability. So ApoE was then constructed into two types: N terminal (NT)-ApoE and C terminal (CT)-ApoE, which can conveniently control ApoE orientation while functionalizing them on the NP surface. CT-ApoE functionalized silicas (CA-SNPs) keep the affinity with their receptors in vitro, and a little higher affinity was verified than NA-SNPs. Also, its PC component, intracellular distribution, and secretion were studied. Even though a lower uptaken was checked in vivo, CA-SNPs still have the potential of being an active targeting nanocarrier.