Date of Award
2026
Degree Type
Thesis
Degree Name
Master of Science in Chemical Engineering (MSChE)
Department
Chemical, Biomolecular, and Materials Engineering
First Advisor
Ryan Poling-Skutvik
Second Advisor
Daniel Roxbury
Abstract
Cancer survival depends strongly on the stage at which the disease is detected, motivating the development of biosensors capable of identifying early changes in cellular state. Single-walled carbon nanotubes (SWCNTs) are promising intracellular biosensors because their intrinsic near-infrared fluorescence, photostability, and tunable surface chemistry and lenght enable prolonged measurements in living cells. Disease such as cancer can progress and alter intracellular physical properties, suggesting that SWCNT motion may provide a physical readout of changes in cellular state. Interpreting this motion is challenging, however, because the cytoplasm is structurally heterogeneous and contains both passive fluctuations and active transport processes. As a first step toward understanding SWCNT transport in cells, this thesis compares their dynamics with those of spherical nanoparticles (SNPs) of comparable characteristic dimensions in semidilute poly(ethylene oxide) solutions of varying concentration and molecular weight. SWCNTs exhibit diffusivities up to 300x greater than Stokes--Einstein predictions. Their dynamics collapse onto a single curve as a function of nanotube length relative to the polymer correlation length, identifying nanotube length as the controlling transport scale. In contrast to SNPs, SWCNTs retain this scaling in the entangled regime and exhibit pronounced non-Gaussian displacement distributions, indicating distinct diffusive modes arising from their anisotropy. Building on this framework, DNA-functionalized SWCNTs are internalized into MCF-7 breast cancer cells and used to probe systematically induced changes in the intracellular physical environment. Their mobility increases progressively from 0.5 to 48 h after internalization. Hyperosmotic treatment with sucrose produces an immediate and concentration-dependent reduction in DNA--SWCNT mobility that persists for up to 6 h. Together, these results establish how particle geometry and local microstructure govern SWCNT transport and demonstrate that intracellular DNA--SWCNT dynamics can report controlled changes in cellular physical state.
Recommended Citation
Yari, Sepehr, "DYNAMICS OF SINGLE-WALLED CARBON NANOTUBES IN STRUCTURED COMPLEX FLUIDS" (2026). Open Access Master's Theses. Paper 2743.
https://digitalcommons.uri.edu/theses/2743