Date of Award
12-24-2025
Date Published
January 2026
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biomedical and Chemical Engineering
Advisor(s)
Pranav Soman
Keywords
3D Osteocyte Networks;3D Printing and Microfluidic Chip;Dynamic Coculture and Triculture;Intracellular Calcium Signaling;Organ on a chip and Microphysiological System;Pulsatile Unidirectional Fluid Flow Stimuli (PUFFS)
Abstract
The Bone Multicellular Unit (BMU) consists of osteocytes (OCYs), osteoblasts (OBs), and osteoclasts (OCs). Three-dimensional (3D) OCY networks are the framework of the BMU, utilizing short-term signals to regulate the long-term responses of bone-forming OBs and bone-resorbing OCs. Interactions within the BMU are challenging to capture in real-time due to their interwoven multicellular structure and OCYs entrapped within an opaque bone matrix. To address this challenge, BMU-like in vitro models have been developed, utilizing a similar 3D microenvironment as in vivo models but more accessible and manipulable compared to bone explants. Despite the potential of these models, successfully integrating all three BMUs within a physiologically relevant dynamic culture system, and doing so under repeatable and reproducible experimental conditions, remains an underdeveloped process. This work aims to utilize microfluidic-based mono-, co-, and tri-cultures under dynamic conditions as system validation templates to develop and design a BMU-on-a-Chip model. Chapter 1 serves as an introduction, covering the BMU and techniques for developing in vitro models, while Chapters 2 and 3 outline the experimental design for the development process. Chapter 2 examines the monoculture system of 3D OCY-laden collagen networks under pulsatile unidirectional fluid flow stimuli (PUFFS). Here, we assess cell viability, gene and protein expression, real-time calcium responses, including the design and fabrication of the three-chambered microfluidic chip, OCY encapsulation, and characterization of PUFFS. Chapter 3 examines mono- and coculture systems with or without 3D OCY-laden collagen networks. Here, coculture interactions are characterized and compared to monoculture responses before creating a triculture system to develop the BMU-on-a-Chip. Chapter 4 is a summary of the completed work. Finally, Chapter 5 discusses future work, including suggestions for protocol improvement and potential additions to the BMU-on-a-Chip model.
Access
Open Access
Recommended Citation
Merife, Anna-Blessing, "BONE MULTICELLULAR UNIT (BMU) ON A CHIP" (2025). Dissertations - ALL. 2223.
https://surface.syr.edu/etd/2223
Caption: Representative video file showing deformation of collagen gel with encapsulated fluorescent beads in chamber 2 when subjected to PUFFS at 0.33 Hz. (Captured at 7 frames per second).
MerifeA2025AppendixB.mp4 (3464 kB)
Representative video file showing calcium signal propagation (right to left) across 3D MLO-Y4 networks in chamber 2 during PUFFS application at 0.33 Hz.
MerifeA2025AppendixC.mp4 (5158 kB)
3D reconstruction of 2D z-projection generated by ImageJ volume viewer showing osteocyte cell networks within 3D collagen gel on Day 3.
MerifeA2025AppendixD.mp4 (1916 kB)
Representative video file showing no detectable deformation of collagen gel. Here, 1 μm fluorescent beads were encapsulated within collagen in chamber 2 and subjected to PUFFS at 0.33 Hz. (Video is captured at 7 frames per second)
MerifeA2025AppendixE.mp4 (26640 kB)
3D reconstruction of OCY454 networks within 3D collagen gel in chamber 2 of PDMS chips on Day 31 using Image J volume viewer.
