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Author ORCID Identifier

https://orcid.org/0000-0002-4959-0860

AccessType

Open Access Dissertation

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Chemistry

Year Degree Awarded

2023

Month Degree Awarded

September

First Advisor

Michelle Farkas

Subject Categories

Analytical, Diagnostic and Therapeutic Techniques and Equipment | Chemicals and Drugs | Laboratory and Basic Science Research | Life Sciences | Medicine and Health Sciences | Organic Chemicals

Abstract

CHEMICAL MODIFICATION AND EVALUATION OF CELLS TOWARDS USE AS DELIVERY TOOLS

SEPTEMBER 2023

BISHNU PRASAD JOSHI

M.S., SRI SATHYA SAI INSTITUTE OF HIGHER LEARNING

Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST

Directed by: Professor Michelle E. Farkas

Endogenous cells are being studied for use in various applications, such as next generation therapeutics and drug delivery vehicles. This is on account of their biocompatibility, amenable distribution profiles, and in many instances, recruitment to and localization of diseased tissues. Multiple cell types have been employed, including macrophages, stem cells, red blood cells, and T cells. Most examples of cell-based delivery utilize phagocytosed entities as cargo. However, uniform, and timely loading and release of phagocytosed agents from the cellular vehicles remains a challenge. In this thesis, Idescribe the use and study of approaches that circumvent these limitations, while harnessing the beneficial characteristics of cells as targeted agents. Through collaborative work, we combined the inherent homing properties of macrophages with on-site manufacturing capabilities of bio-orthogonal nanozymes (NZs), by incorporating the latter

into cells. We were able to show that the NZs can be internalized by macrophages without impacting their behavior, and while internalized, NZs can convert inactive pro-drugs to their active forms. In the latter half of this thesis, I describe studies involving cell surface modifications, which can be used to append imaging and/or chemotherapeutic agents for delivery applications. I used different types of mild bioconjugation chemistries at native and installed moieties on immortalized, model macrophages. The covalent surface modifications were assessed and their effects on cellular characteristics like viability, motility, chemotaxis, and phenotypic polarization are reported. Further, I showed that the modified cells can be used to evaluate macrophage-cancer interactions in both in vitro and in vivo models. Continuing this line of work, I expanded the studies to primary and immortalized macrophages and stem cells. I characterized the N-Hydroxysuccinimide (NHS) modification in terms of retention at the cell surface over time and determined effects on cellular characteristics like viability and migration. This work now sets the stage for further use of surface-modified cells as diagnostic tools and as delivery agents for therapeutics and molecular probes. In summary, this thesis explores the potential of cells for use in delivery and imaging applications beyond payload internalization, with a focus on facile chemical modifications at their surfaces.

CHEMICAL MODIFICATION AND EVALUATION OF CELLS TOWARDS USE AS DELIVERY TOOLS

SEPTEMBER 2023

BISHNU PRASAD JOSHI

M.S., SRI SATHYA SAI INSTITUTE OF HIGHER LEARNING

Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST

Directed by: Professor Michelle E. Farkas

Endogenous cells are being studied for use in various applications, such as next generation therapeutics and drug delivery vehicles. This is on account of their biocompatibility, amenable distribution profiles, and in many instances, recruitment to and localization of diseased tissues. Multiple cell types have been employed, including macrophages, stem cells, red blood cells, and T cells. Most examples of cell-based delivery utilize phagocytosed entities as cargo. However, uniform, and timely loading and release of phagocytosed agents from the cellular vehicles remains a challenge. In this thesis, Idescribe the use and study of approaches that circumvent these limitations, while harnessing the beneficial characteristics of cells as targeted agents. Through collaborative work, we combined the inherent homing properties of macrophages with on-site manufacturing capabilities of bio-orthogonal nanozymes (NZs), by incorporating the latter

into cells. We were able to show that the NZs can be internalized by macrophages without impacting their behavior, and while internalized, NZs can convert inactive pro-drugs to their active forms. In the latter half of this thesis, I describe studies involving cell surface modifications, which can be used to append imaging and/or chemotherapeutic agents for delivery applications. I used different types of mild bioconjugation chemistries at native and installed moieties on immortalized, model macrophages. The covalent surface modifications were assessed and their effects on cellular characteristics like viability, motility, chemotaxis, and phenotypic polarization are reported. Further, I showed that the modified cells can be used to evaluate macrophage-cancer interactions in both in vitro and in vivo models. Continuing this line of work, I expanded the studies [MF1] [BJ2] to primary and immortalized macrophages and stem cells. I characterized the N-Hydroxysuccinimide (NHS) modification in terms of retention at the cell surface over time and determined effects on cellular characteristics like viability and migration. This work now sets the stage for further use of surface-modified cells as diagnostic tools and as delivery agents for therapeutics and molecular probes. In summary, this thesis explores the potential of cells for use in delivery and imaging applications beyond payload internalization, with a focus on facile chemical modifications at their surfaces.

[MF1]Because the amine items had to be removed, this is no longer the case.

[BJ2]I clarified this was only NHS modification expanded to primary and immortalized macrophages and stem cells.

DOI

https://doi.org/10.7275/36001760

Creative Commons License

Creative Commons Attribution-Noncommercial 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

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