SPATIOTEMPORAL AND COMBINATORIAL DELIVERY OF MIRNAS FOR MODULATION OF OSTEOGENESIS IN HUMAN ADIPOSE STEM CELLS

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Author:
Abu Laban, Mohammad
Graduate Program:
Bioengineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
May 06, 2019
Committee Members:
  • Daniel J Hayes, Dissertation Advisor
  • Daniel J Hayes, Committee Chair
  • Scott H Medina, Committee Member
  • Jian Yang, Committee Member
  • Sulin Zhang, Outside Member
Keywords:
  • gold
  • silver
  • nanoparticles
  • plasmon
  • microrna
  • mir-148b
  • mir-21
  • diels-alder
  • thermal
  • photothermal
  • osteogenesis
  • hASCs
  • tissue
  • regeneration
  • retro-diels-alder
  • mineralization
  • spatiotemporal
  • targeted
  • drug delivery
  • nucleic acid
Abstract:
Short non-coding nucleic acid molecules play an important role in regulating gene expression in numerous processes from embryonic to immune system development, and have been sought after as potential therapeutic agents relevant to human physiology and pathology. However, clinical translation has been limited due to risks involving unspecified off-target effects and inefficient delivery. With the capability to respond to internal or external stimuli, nanoparticle delivery systems hold great promise for efficient spatiotemporal gene control for therapeutic applications. Additionally, techniques that allow for delivery of heteroplexed nucleic acid sequences with precise sequential and spatial targeting could result in improved control of processes such as wound repair. For attachment of the therapeutic, computation modeling suggested the possibility of three alternate chemistries to tether amine-terminal biomolecules onto nanoparticles using thermally-labile linkers. Using the versatile tool of the retro-Diels-Alder (DA/rDA) chemistry, we synthesized three cycloadducts that thermally cleaved at different temperature ranges. Furthermore, we utilized the unique properties of noble metal nanoparticles and their distinct plasmonic abilities to induce surface release. With these tools, we demonstrated the sequential delivery of two miRNA structures for an enhanced osteogenic effect of human adipose stem cells (hASCs). Furthermore, using a 3D collagen culture as a model, we have shown the ability to deliver miR-148b for bone differentiation of hASCs within the outer-band region of the hydrogel, and miR-21 in the centered cells for increased adipogenic differentiation. Utilizing the capability of the retro-Diels-Alder chemistry and the differential optical photothermal responses of gold and silver nanoparticles, spatially discrete differentiation into two different tissue types was achieved. In summary, the presented document demonstrated three alternate DA linkers with varying thermal responses and rDA kinetics, sequential miR-148b and miR-21 release via co-delivery on photo-responsive gold and silver nanoparticles, and spatially targeted mineralization and adipogenic regeneration across different sections of our collagen model.