Dissertation
Technologies for pathogenisensing and delivering therapeutic agents
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2023
DOI: 10.25820/etd.006953
Abstract
New technologies for pathogenesis sensing and therapeutic agent delivery systems are continuously growing. Developing novel technologies for sensing disease-causing biomarkers is crucial for better disease monitoring and treatment planning, especially for cancer, since it is a leading cause of death worldwide. An effective detection approach should ideally be minimally invasive, easy to use, and cost-effective. Liquid biopsy technology meets these specifications and is increasingly used for cancer profiling. It is believed to help enable a precision oncology approach. Liquid biopsy refers to the blood test that detects signs of cancerous tumors, mainly circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA).
In the other part of this research, we focused on the delivery systems of therapeutic agents. The delivery systems of therapeutic agents are being extensively studied to explore delivery strategies, approaches to defeat delivery barriers, and understanding the immune response triggered by the delivery system. Therefore, delivery system practices have changed drastically in the last few decades and are expected to witness even more significant changes.
In chapter 1, we aimed to investigate the ability of two different liquid biopsy technologies (the RareCyte® method and the ParsortixTM method) to detect and enumerate CTCs in blood samples from patients with gastrointestinal malignancies; and to correlate the acquired data with different clinical variables, including tumor type, progression, and treatment response. Both devices tested were able to detect CTCs from the blood samples, and it was found that the enumerated CTCs levels were affected by the investigated clinical variables. This work suggests the feasibility of including a CTC detection platform in clinical settings for real-time cancer patient status monitoring.
In chapter 2, we aimed to develop a highly sensitive vertical silicon nanowire (vSiNW) biosensor platform for detecting DNA and alterations of even a single base pair in DNA sequences. We successfully functionalized the vSiNW array surface and immobilized a capture DNA that can detect a complementary strand upon its hybridization with the immobilized capture DNA. We also showed that the developed platform can differentiate between detected DNA strands even when there is less than 100% homology. The vSiNW array biosensor platform might provide a practical way to detect DNA mutations in clinically relevant samples and provide real-time results.
In chapter 3, a mode of lyophilizing polyplex nanoparticles was investigated with the aim of achieving stably stored formulations. We compared two common lyoprotectants (sucrose and polyvinylpyrrolidone K30 (PVP)) with, for the first time, sucralose (a sucrose derivative used as an artificial sweetener), demonstrating that sucralose can act as a lyoprotectant for polyplex solutions. We used titanium discs to deliver the lyophilized polyplexes to human embryonic kidney cells (HEK 293T) and found that lyophilized polyplexes in the presence of a lyoprotectant displayed both preserved particle size and high transfection efficiencies compared to those lyophilized with no lyoprotectant. We found that sucralose as a lyoprotectant had comparable activity to sucrose and was superior to PVP in preserving the particle surface charge. These results suggest that lyophilization of polyplexes with sucralose can provide a method for stabilizing and preserving their activity for long-term storage.
In chapter 4, we developed alginate electro-responsive hydrogels by incorporating poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS), a highly electroconductive polymer. We developed hydrogel complexes of sodium alginate (SA) and polydimethylsiloxane (PDMS) (SA/PDMS) and of SA and chitosan (SA/chitosan). The SA/PDMS hydrogel complexes were loaded with calf thymus DNA or baricitinib, while the SA/chitosan hydrogel complexes were loaded with baricitinib. It was found that applying +12 volts (V) for 10 minutes to the hydrogel complexes loaded with calf thymus DNA increased its release by 3-13-fold. These results suggest that smart electro-responsive hydrogel complexes can provide a potential method for controlling therapeutic agent delivery.
In summary, we have investigated the feasibility of including a CTC platform in clinics using two different approaches: RareCyte® and ParsortixTM. We have successfully developed a highly sensitive biosensor platform (vSiNW) for detecting DNA strands that can specifically bind the target DNA sequence. It was shown that polyplex nanoparticles could be stably stored using a novel lyophilization method. Finally, we developed a smart electro-responsive hydrogel complex that could deliver calf thymus DNA in response to applying an external electrical stimulus.
Details
- Title: Subtitle
- Technologies for pathogenisensing and delivering therapeutic agents
- Creators
- Walla Ibrahim Malkawi
- Contributors
- Aliasger K Salem (Advisor)Fatima Toor (Committee Member)Pashtoon M. Kasi (Committee Member)Lewis L. Stevens (Committee Member)Marie E. Gaine (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Pharmacy (Pharmaceutics)
- Date degree season
- Summer 2023
- DOI
- 10.25820/etd.006953
- Publisher
- University of Iowa
- Number of pages
- xxii, 111 pages
- Copyright
- Copyright 2023 Walla Ibrahim Malkawi
- Language
- English
- Date submitted
- 07/24/2023
- Description illustrations
- illustrations, tables, graphs
- Description bibliographic
- Includes bibliographical references (pages 102-111).
- Public Abstract (ETD)
- Technological advances in pathogenesis sensing and therapeutic agent delivery systems have remodeled disease monitoring and treatment planning. This research aims to explore novel approaches for detecting disease-causing biomarkers, explicitly focusing on cancer liquid biomarkers and developing effective delivery systems for therapeutic agents.
For detecting disease-causing biomarkers, firstly, we investigated the feasibility of introducing circulating tumor cells (CTCs) detection platforms into clinics by testing two platforms (RareCyte® and the ParsortixTM method). This research highlights the potential benefits of incorporating a CTC detection platform in clinics, offering sensitive and reliable diagnostic tools. Secondly, we successfully developed a novel, sensitive, cost-effective, portable, and easy-to-use vertical silicon nanowires (vSiNW) biosensor platform for detecting specific DNA strands. This platform holds great potential as a point-of-care detection technique for identifying clinically relevant DNA mutations associated with various diseases.
For developing effective delivery systems for therapeutic agents, we first effectively developed polyplex nanoparticles capable of being stably stored using a lyophilization technique. This method ensures the stability and functionality of the polyplex nanoparticles over an extended period. Secondly, we developed smart electro-responsive hydrogels, which can release calf thymus DNA in response to electrical stimuli. This advancement opens possibilities for targeted and controlled drug delivery systems.
In summary, this research explores various cutting-edge technologies and methodologies. These advancements hold excellent potential for improving disease monitoring, treatment, treatment planning, and patient outcomes.
- Academic Unit
- Pharmacy; Craniofacial Anomalies Research Center
- Record Identifier
- 9984454434202771
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