Biopolymer nanocomposites for food and healthcare applications

Abstract

This dissertation focuses on development of biopolymers by integrating nanomaterials to improve the properties of pristine polymers for enhancing the performances of chemical sensors and laser desorption/ionization mass spectroscopy (LDI-MS) applied for food quality control health monitoring and biomedical applications. The dissertation is divided into 4 parts: the first part, polylactic acid and cellulose were used for dual detection platform of biogenic amines for food spoilage indication. Highly porous PLA film is fabricated by adding nanosized calcium carbonate resulted in high sensing element entrapment. On another side of platform, pristine cellulose is modified with graphene oxide and exploited a substrate for LDI-MS. This dual platform is used for food quality monitoring. The second part, a bacterial nanocellulose hydrogel with reswelling ability and high swelling ratio is fabricated by introducing carboxymethyl cellulose into the nanocellulose network, and the obtained hydrogel is used as a colorimetric sensor for sweat pH and glucose. The third part, the surface of a commercial contact lens is modified with nanocomposite composed of levofloxacin and cellulose nanofibrils to create a theranostic contact lens for ocular infection, which the cellulose nanofibril helps improving drug entrapment, wettability and pH-sensitiveness to the pristine contact lens in order to control the releasing amount of levofloxacin depending on infection severity. The developed theranostic contact lens also indicates severity of infection by colorimetric pH sensor. Lastly, fourth part, chitosan is incorporated with developed titanium dioxide/nitrogen-doped graphene nanocomposites to enhance laser-absorbing and desorption property, leading to enhanced ionization efficiency of analytes without using an additional matrix, and utilizes as a novel substrate of LDI-MS for biomolecules determination.