UC Riverside

Magnetic nanomaterials (MNMs) have gained considerable attention for their unique properties, including superparamagnetism and excellent biocompatibility. In addition, Magnetic nanorods, benefiting from their unique structure, exhibit additional attractive properties such as molecular transportation enhancement. This dissertation explores the development of biosensing and bioseparation techniques based on the magnetic nanorods targeting extracellular vesicles (EVs) and cannabis. Chapter 2 introduces NOBEL-SPA, a method for single EV miRNA analysis. The utilization of antibody-modified magnetic nanorods (NOBs) could facilitates rapid target binding and impurity removal. NOBEL-SPA can detect as few as 3-4 EV particles/µL in biological samples within approximately 4 hours, without any pre-processing. This technique has proven effective for real-time monitoring of EV secretion and the enclosed miRNAs in cell cultures. Importantly, it also allows for precise differentiation between clinical patients and healthy individuals by selecting appropriate target miRNAs and capture antibodies. In Chapter 3, NOBEL-SPA was extended for the simultaneous detection of dual markers—surface protein and miRNA. This strategy enabled the differentiation of distinct EV sub-populations, aiding in determining their cellular origin. Moreover, our method's efficacy in clinical applications was highlighted as we distinguished breast cancer patients from healthy controls. Notably, we could discern the differences between healthy individuals, Stage I, and Stage II breast cancer patients based on select protein/miRNA combinations. Chapter 4 details an advanced methodology based-on NOBs for the total capture and selectively release of specific EV subpopulations using a cascade DNA chain reaction. This allows for the collection of all EVs, followed by the targeted release of subgroups based on identified markers. By employing existing technologies such as sequencing or proteomics to examine these EV subpopulations, our ultimate objective is to identify new markers or marker combinations that will significantly improve disease diagnosis and treatment. Finally, Chapter 5 employs magnetic nanorods modified with zwitterionic polymers and an engineered plant hormone receptor, Pyrabactin Resistance 1 (PYR1), to detect cannabis. The design optimizes signal-to-noise ratios and offers impressive specificity. The developed sensors can detect cannabinoids in biofluids like saliva, urine, and serum with low limits of detection and wide dynamic ranges, all within 30 minutes. Overall, magnetic nanorods demonstrate considerable promise for advancing the fields of bioseparation and biosensing.