Chemistry & Biochemistry Resources: Gaines Research Group

Microgels and hydrogels are composed of 3D polymer networks, swollen in a good solvent. The “hydro” part in the name hydrogel is indicative of the good solvent being water, which makes up the majority of the total volume and leaves the remaining volume to the actual polymer chains and crosslinks. Polymers made into microgels and hydrogels with the same chemical makeup but would possess different physical material properties. Hydrogels are bulk films of 3D polymer networks and are often referred to as macrogels. Microgels are hydrogels made into dispersions of discrete colloidal particles, which range in size between tens of nanometers and several microns. The physical differences between microgels and hydrogels lead to different physical properties. Because microgels are much smaller in size and can be treated as a suspension of individual particles, microgels possess much faster swelling kinetics than hydrogels and they can be directed to assemble into monolayers and 2D arrays.

Microgels and hydrogels have expanded the field of soft matter. They have been built into materials for cosmetic products, biomaterials, food packaging and additives, and oil refinement. They are often synthesized from polymers that are responsive to an external stimulus such as temperature, pH, light, or electric field. These environmentally sensitive polymers induce drastic changes to the phase behavior of microgels and hydrogels, which cause them to reversibly change volume by absorbing and releasing the aqueous solvent that they are swollen in according to the conditions of their microenvironment. The ability for microgels and hydrogels to switch the phase behavior increases the capacity for multifunctional material properties for a desired application. Since microgels are small compared to macrogels and hydrogels, the diffusion rate across each particle is much faster than their macro counterparts. Thus, microgels display fast swelling kinetics, which gives them an advantage for some applications over bulk macrogels.

YouTube Videos:

Microgels & Nanogels  https://youtu.be/0o1mNtNdkE8

Characterizing Nanostructures by Light Scattering https://youtu.be/xiPxXnSawNM

Nanomaterials Webinar: Smart Fluids, Gels, and Rheology https://youtu.be/lZb01DAhcZo

How does potentiometry work? https://youtu.be/0-nbyzUplyU

Microgels and hydrogels can be designed with additional functionality through copolymerization and postpolymerization modification. These functional modifications can dictate the swelling dynamics of the system, and their chemistry can also induce a triggered response from an applied external stimulus (temperature, light, pH, ionic strength electric field). In this project, we study the differences in biomolecular conjugation distribution and density that result from changing the physical and chemical properties of the microgel particles. We use potentiometric and conductometric titration to measure these differences, and we compare these results with measurements collected from biomolecule assays and fluorescence microscopy.

Greg T. Hermanson, Bioconjugate Techniques, 3rd Edition 2013

The Gaines lab also explores the interfacial chemistry between cells and hydrogels on biological interfaces. This project focuses on developing a synthetic 3D culture microenvironment for biomedical applications. The aim is to gain a sophisticated understanding on how cells respond to specific controlled variances in the material properties of the extracellular matrix, to predict strategies to issue control over cell behavior in physiological systems.

NIH 3T3 Cells cultured with microgel particles after 1-day (left); in collagen hydrogel film. Scale bar = 100 um.

Hair is the primary differentiator for mammals, and humans use it to infer the state of a person’s health, class, and age. Traditionally, hair types have been defined and cared for according to three major phenotypic differences: 1) Caucasian, 2) African, 3) Asian. We are now aware of many more distinct differences between the three classes of hair, and there have been many, many products developed to care for all of these types. While most of the motivation for developing hair care products focuses on creating consumer products, there is interest in understanding the fundamental science on how the interfacial chemistry, physics and biology of hair contribute to the Material Properties that hair exhibits. The objective of this research is to develop a fundamental understanding on how specific hair products affect overall hair health. Of most interest is developing an understanding for how surfactants cause tress damage.

YouTube Videos:

Internal Chemical Bonds of Hair: https://youtu.be/C6SDKsUTdhM

Chemistry of Haircolor Review: https://youtu.be/8X4LeI1TsKQ

Chemistry of Perms Vs. Relaxers: https://youtu.be/g-6kdCCvetM

Project 4: Interfacial Chemistry of Microgel Particles with Polymer Materials

• Block Copolymer Thin Films
• Covaserates
• Nanocellulose

Block copolymer films manipulate the pathway of light for reconfigurable optical materials for emergent optical quantum computing systems. 

Project 5: Climate Change & Renewable Energy

Research Project Components – research question, background, hypothesis, relevant databases, analyses

1. Identify the research problem clearly and justify its selection,
2. Review previously published literature associated with the problem area,
3. Clearly and explicitly specify hypotheses [i.e., research questions] central to the problem selected,
4. Effectively describe the data which will be necessary for an adequate test of the hypotheses and explain how such data will be obtained, and
5. Describe the methods of analysis which will be applied to the data in determining whether or not the hypotheses are true or false.
6. Complete data analysis
7. Prepare report and presentation of project

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