Purdue University Graduate School
Juan Arango dissertation (FINAL).pdf (5.84 MB)

Surface functionalization of hydrogels below the length scale of heterogeneity: Methods and high-throughput production

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posted on 2024-06-18, 12:54 authored by JUan Camilo ArangoJUan Camilo Arango

Creating synthetic materials that mimic native tissue is an overarching goal in tissue engineering and regenerative medicine. It is essential to embed molecular-resolution chemical patterning into soft synthetic polymers to achieve this. Even though fundamental principles from surface science offer broad control over the position of even individual atoms on a pristine surface, this degree of control remains restricted to two-dimensional hard crystalline materials under particular environmental conditions that are incompatible with life. Therefore, developing strategies to translate these principles into soft, amorphous interfaces is challenging. This will lead to the development of nanopatterned soft materials that closely resemble native tissue. Popular approaches in materials science fail to produce such high-resolution polymers.

Hydrogels are soft, three-dimensional networks that can hold large amounts of an aqueous solvent while retaining their structure. These materials have applicability in contexts where polymer materials must interface with biology (e.g., drug delivery, biosensing, tissue engineering, and regenerative medicine) as one can easily tune their mechanical, chemical, and biological properties. However, the main limitation of these materials is that the hydrogel network is amorphous, with substantial variability in mesh size up to the micron-scale. This limits their application when highly structured interactions with biomolecules, typically at sub-10 nm scales, are required. This dissertation shows a strategy to generate 1 nm-wide ordered patterns of functional groups on polyacrylamide (PAAm) hydrogel surfaces. When 1 nm-wide linear patterns are transferred to PAAm, patterning specific biological polyelectrolyte interactions at the hydrogel surface is possible. This represents a first step towards developing robust methods for nanopattern hydrogels at the proposed resolution.

One last subject this thesis dissertation seeks to explore is the extension of chemical patterning to a dynamic range of scales to adapt this technological advancement to industrial setups. Enabling the practical applicability of nanopatterned soft materials in macroscopic contexts (e.g., synthetic tissue development, wearable electronics, etc). However, extending this degree of control to a high throughput process applicable to heterogeneous interfaces remains a challenge. We demonstrated a scalable inkjet printing method to produce functional hierarchical patterns on two-dimensional crystalline substrates, which can be transferred to hydrogels. Finally, we studied the specific biosensing capabilities of these micro-patterned surfaces.


Schmidt Science Polymaths Award



Degree Type

  • Doctor of Philosophy


  • Chemistry

Campus location

  • West Lafayette

Advisor/Supervisor/Committee Chair

Shelley A. Claridge

Additional Committee Member 2

Julia Laskin

Additional Committee Member 3

Alexander Wei

Additional Committee Member 4

Jonathan Wilker