Investigation Of Self-assembly Bio-nanomaterials Of Phenylboronic Acid Polymer

Because carbohydrates play an important role in many biological or pathological processes, including fertilization, development, autoimmune disease, and cancer metastasis, it should be further developed in novel detection technology ofcarbohydrate as well as polyols-drug delivery system for potential biomedical applications. Phenylboronic acid (PBA) and its derivatives can bind with cis-diol compounds such as sugars, glycolipids and glycoproteins et al through reversible boronate bonds in aqueous solution. Because of this property, it has been considered as an ideal recognition group to specifically bind carbohydrates. In contrast with protein-based glucosesensing systems, such as glucose oxidase and concanavalin A, the PBA-bearing polymers are stable, have low cytotoxicities and do not stimulate strong immune responses. In this dissertation, novel PBA-functionalized nanofilms and nanoparticles were fabricated through layer-by-layer technique and solvent displacement method using poly(acrylamide-co-3-acrylamidophenylboronicacid) and (3-((acrylamido)methy1)phenyl-boronic acid) homopolymer. The self-assembly process of the PBA-functionalized nanomaterials, glucose response to film and cancer capture or release were systematically investigated. The major achievements include:1. Under acidic condition, a PBA multilayer film could be assembled from PSS and poly(acrylamide-co-3-acrylamidophenylboronic acid) using layer-by-layer technique, driven by electrostatic interaction. The assembly was monitored by quartz crystal microbalance (QCM). The film thickness was increased with the increase of the ionic strength of assembly solutions, and the optimized dipping time was 30 min. The multifilm assembled with 12 bilayers were more sensitive in response to glucose than that with 2 bilayers, which indicated that the numbers of PBA groups in self-assemble multifilm increased with more bilayers that leads to improved glucose-response sensitivity. In addition, the surface plasmon resonance (SPR) sensor was coated by the PBA thin film through the layer-by-layer method, which could be used in glucose sensing with high sensitivity and stability.2. A novel glycoprotein film was assembled from pig gastric mucin (PGM) and poly(acrylamide-co-3-acrylamidophenylboronicacid) using layer-by-layer technique, driven by the formation of boronate ester bonds between the boronic acid units and the polyols. The assembly was monitored by QCM and UV-vis spectroscopy. The film thickness was increased with the increase of the ionic strength and the pH of assembly solutions. The dynamic response of the assembled film to glucose was monitored in real time using quartz crystal microbalance with dissipation (QCM-D). It involves two steps:at the first step, similar amount of glucose bound with free PBA groups on the outside surface; at the second step, glucose penetrated the assembly film and disturbed the interaction between PGM and PBA. The disassembly rate was a function of the glucose concentration, and the film was also sensitive to glucose at the physiological condition, albeit the response was weaker and slower than that at higher pH.3. Two kinds of PBA-functionalized films in different morphologies (PDDA/PBAH and PDDA/PBAS) were assembled using (3-((acrylamido)methyl)phenylboronic acid) homopolymer (PBAH) and PBA-functionalized nanoparticles, driven by electrostatic interaction. QCM-D was utilized to monitor HepG2 cells behavior on PBA-functionalized films in real-time. â–³D/â–³f polts were used to describe the morphology change and cytoskeleton remodeling of HepG2 cells interacting with the quartz crystal, which indicated that the adhesion process of HepG2 cells involves three steps, i.e. non-specific adhesion, the interaction between cell member receptor and assembly surface, and cell spreading. In contrast with PDDA/PBAH film, the more rapid spreading dynamics of the cells was clearly evident on PDDA/PBAS film which contributed to cell adhesion. In addition, cell release process on PDDA/PBAS film was regulatedby glucose concentration.4. Stable and monodisperse phenylboronic acid nanoparticles (PBA-NPs) were fabricated using poly(3-((acrylamido)methyl)phenylboronic acid) (PBAH) via a solvent displacement method. The diameter of assemble nanoparticles was approximate 100 nm. The effect of operating parameters, including stirring time, initial polymer concentration and the proportion of methanol, on the self-assembly process were systematically investigated. The diameters of the PBA-NPs were increased as the increase of the initial PBAH concentration and the proportion of methanol. The resulting PBA-NPs could successfully encapsulate emodin based on PBA-diol interaction, which potently improved the solubility and availability of polyols drugs in aqueous solution. The encapsulation efficiencies (EE%) of emodin were 78.0%. In vitro release profiles revealed that a burst release occurred in response to pH 5.0 because of the disassociation of boronate ester bonds. Likewise, PBA-NPs showed negligible cytotoxicity in both cell lines, while PBA-Emodin-NPs showed a much higher cytotoxicity to HepG2 cells (cancer cells) than that to MC-3T3-E1 cells (normal cells).In conclusion, various PBA-functionalized films could be prepared through layer-by-layer technology, and PBA-functionalized nanoparticles were synthesized using a solvent displacement method. Our works may lead to the development of PBA-functionalized nanomaterials with good stability and biocompalibility as well as potential biomedical applications.