Project Title: Plasma Surface Activation Chamber for Biomaterials Lab and Senior Design Projects

Project Lead's Name: Amy Yousefi

Project Lead's Email: yousefiam@MiamiOH.edu

Project Lead's Phone: 513-529-0766

Project Lead's Division: CEC

Primary Department: CPB

List Departments Benefiting or Affected by this proposal: CPB

Estimated Number of Under-Graduate students affected per year (should be number who will actually use solution, not just who is it available to): 60

Estimated Number of Graduate students affected per year (should be number who will actually use solution, not just who is it available to): 5

Describe the problem you are attempting to solve and your approach for solving that problem: We currently have no lab experiments to compare the surface energies of biomaterials or to show the effect of surface modification on altering the hydrophobicity of a biomaterial. This is a very important practical aspect, which directly affects the suitability of a material for biomedical applications. When exposed to surrounding air, hydrophobic elements tend to migrate to the surface of a biomaterial. In addition, contaminants in air can readily cover the surface of certain biomaterials, depending on the magnitude of their surface energy (Fig. 1, attachment). The plasma surface activation chamber requested in this proposal can greatly benefit the students enrolled in CPB 419/519. The chamber can be used for etching of thin polymer films (10's to 100's nm thick), with an organic film removal rate of ~7 nm/min. Hence, the chamber would offer an effective method for sterilization by allowing nanoscale cleaning, while enabling surface activation that alters the surface energy.

The equipment can also play a key role in cell adhesion to 3D scaffolds. Figure 2 shows a PLGA scaffold that we have fabricated in our lab. These hierarchical scaffolds with micro-, macro- and nano-scale features can contribute to cell attachment and growth via different mechanisms. The requested plasma surface activation chamber will be used in CPB 419/519 lab for surface modification of the scaffolds. Samples before and after surface modification will be used for contact angle measurements. The water contact angle formed on the surface of the PLGA will be analyzed to compare the surface energy before and after surface activation. As previously indicated, the CPB department also offers other experiential learning opportunities for undergraduate students, such as independent studies (CPB 277/377) and senior design projects (CPB 471/472). Therefore, these students as well as graduate students will also have access to this equipment.

How would you describe the innovation and/or the significance of your project: Students majoring in bioengineering are required to take a biomaterials course (CPB 519/519, 3 credit hours). This course also serves as an elective course for our students majoring in chemical engineering. The course has an enrollment of ~45 undergraduate students and 3–5 graduate students per year and includes lab experiments that offer hands-on experience with biomaterials. In addition, since 2009 my lab has served over 50 undergraduate students on the development of 3D scaffolds for tissue engineering in the context of senior design projects (CPB 471/472) and independent studies (CPB 277/377), as well as 9 graduate students on their MS thesis (CPB 700) on biomaterials. In CPB 419/519, the students prepare soft-tissue mimicking hydrogels (cryogels) in the lab and learn about additive manufacturing of tissue-engineering scaffolds. This experiential learning is a key element of their undergraduate education and prepares them for careers in medical device companies and research labs.

Some important topics that are covered in the course include surface characterization of biomaterials, surface energy, and surface contamination in air and water. The hydrogels produced in the course lab are made of hydrophilic polymers, such as poly(vinyl alcohol) (PVA), whereas the 3D scaffolds are made of relatively hydrophobic polymers, such as poly(lactic-co-glycolic acid) (PLGA). The plasma surface activation chamber requested in this proposal can be used for sterilization by allowing nanoscale cleaning, while enabling surface activation that affects the surface energy. In addition, the chamber can be used for etching of thin polymer films (10's to 100's nm thick), with an organic film removal rate of ~7 nm/min. This can play a key role in cell adhesion to 3D scaffolds. In the proposed lab experiment, PVA and PLGA samples will be exposed to water before and after surface medication. More specifically, the water uptake (PVA) and water contact angle (PLGA) will be analyzed before and after surface treatment.

How will you assess the success of the project: Figure 3 shows some hydrogels produced by the freeze-thaw technique. The material used for producing these gels is an aqueous solution of poly(vinyl alcohol) (PVA). Here are the steps that students will follow:

• PVA (1 gr) and DI water (20 ml) will be mixed, sonicated and heated at 85 C on a hot-plate/stirrer.
• The prepared solution will be poured into aluminum molds (20-mm diameter).
• The set-up will be placed inside a freezer at -20C.
• The samples will be removed from the freezer after 24 hour.
• After removing from the freezer, one wet sample will be weighed (M1,t0) and immersed in DI water inside an incubator (37 C).
• After removing from the freezer, two wet samples will be placed inside the plasma surface activation chamber for two different periods, weighed (M1,t1 and M1,t2), and immersed in DI water inside an incubator (37 C).
• The water-swollen samples will be weighed after 7 days (to measure M2,t0, M2,t1 and M2,t2) after dabbing the surface water with a filter paper.
• The water uptake (swelling) will be calculated as follows (all three samples): WU (%) = [100 × (M2,t – M1,t) / M1,t]
• Once the team reports were submitted (part I), the collected data by all teams will be uploaded to Canvas to allow students perform statistical analysis (mean, standard deviation, and t-test).

The reports submitted by students in previous years indicate that they learn significantly by performing lab experiments. Here are two examples showing how Tech Fee funds in the past have contributed to the students' learning outcomes (as listed in the course syllabus):

(a) A Tech Fee award in 2017 was used to order an incubator for observing the hydrogel swelling at the physiological temperature. The final Tech Fee report was submitted in June 2018. Figure 4 shows the results obtained in the lab by the students. The student’s t-Test showed a statistically significant difference between the swelling in room temperature and inside the incubator purchased using the Tech Fee fund.

(b) A Tech Fee award in 2016 was used to order a freeze-dryer (with additional cost-share from CPB and OARS). The final Tech Fee report was submitted in April 2017. The students enrolled in CPB 419/519 used this equipment for hydrogel fabrication. Figure 5 shows the effect of drying method on cryogel network formation and water content.

Total Amount Requested: $8,700

Budget Details:

1. PDC-001-HP High Power Expanded Plasma Chamber - $5,750 after 10% discount
2. Dry oxygen pump, 115v (includes adaptor, centering ring, connectors and hose) - $2,950

Is this a multi-year request: No

Please address how, if at all, this project impacts any of Miami's BCSAE, 2020, or divisional plans:

• Miami's BCSAE has identified healthcare (e.g., medical device industry) as a field of interest. Our students have been hired by some leading medical device companies in the past few years.
• Note that a key element of Miami's BCSAE is to "advance knowledge in the professional fields considered most in-demand throughout Ohio, the region and the nation." As described earlier, the course and its lab will help to "Prepare students with the versatile skills and mindset to meet the needs of a demanding and dynamic workforce".
• The 3D scaffolds prepared in senior design projects is related to an ongoing study funded by the National Institute of Health (NIH). Hence, the proposed application could contribute to "Miami’s reputation for excellence and innovation in broad, transdisciplinary areas of research and pedagogy."