Two-dimensional exploration of two-dimensional carbon : imaging and sensing applications

Abstract

With the emerging need for advanced sensing and imaging capabilities in personalized healthcare, there has been motivation to develop new classes of nanomaterials; with performance vastly superior to existing technologies. In this work, we explore the one- and two-dimensional forms of carbon nanomaterials, namely, single-walled carbon nanotubes (SWNTs), and graphene derivatives (graphene oxide, or GO), for their remarkable potential in biomedical imaging and sensing. This thesis presents three functional applications, along with the necessary processing at the interface of nanotechnology and biomaterials required to achieve the desired set of properties enabling these applications. First, we attempt to address the rise in antibiotic-resistant bacterial infections by developing a nano-probe for targeted sensing, with potential for early, non-invasive diagnosis of infectious diseases through optical imaging. Using genetically engineered M13 bacteriophage, we synthesize biologically-functionalized, aqueous-dispersed SWNTs, for actively-targeted, modularly-tunable, high-contrast, highly-specific detection of deep-tissue pathogenic infections, at an order-of-magnitude lower dosage compared to other probes reported in literature. Second, we investigate the role of guided surgery in enhancing the survival lifespan of patients with gynecological cancers. We deploy a combination of targeted SWNT probes, along with a custom-designed real-time intraoperative imaging system, which offers sub-millimeter resolution at a sensitivity over 93%. Using image-guided surgery in a mouse model of ovarian cancer, compared to the control group receiving non-guided surgery we report improvement in the median survival by 40%, with large societal benefit expected upon clinical translation. Third, we develop a scalable, one-step mild thermal annealing treatment for enhancing the properties of graphene derivatives, with no chemical treatments involved, while preserving the rich oxygen framework in GO unlike current protocols used in literature. This treatment provides a handle to control the spatial distribution of oxygen functional groups on the graphene basal plane. Using nano-bodies decorated on our treated GO substrate, we report 38% increase in the efficiency of cell capture from whole blood, compared to conventional sensors using as-synthesized GO. Finally, we discuss challenges in moving the field forward, and provide a brief glimpse into the next-generation imaging technologies currently under development, which are generally applicable to a much broader class of materials.