Functional materials/surfaces, bioabsorbable materials, and natural minerals
Formulation, separation, processing, characterization, and application
Jeff Brookins
Congratulations to Jeff!
He was selected as the recipient of the Richard Shorraw Award. The Richard Sharrow Award is given to a student who has demonstrated a significant academic improvement through his career at MTU-MSE Department, and has demonstrated good citizenship within the department. Jeff received this award during the Senior Banquette last night (April 13).
He has also received the AFS Detroit-Windsor Chapter’s Past Chairman Scholarship.
Washington D.C.
Two of the SURFI Team members, Jeff Brookins and Philip Staublin traveled to Washington D.C. with a group from Michigan Tech to attend Congressional Visit Day, which is organized by the national chapter of the Material Advantage program. They worked with two other Michigan Tech students to schedule meetings with Michigan congressmen to discuss research funding programs. In Washington, the students spoke to staff members from six offices and advocated for the continuation of funding to programs such as NIH and NSF. Using zinc stents as an example of benefits of NIH research, they hoped to provide officials with justification for opposing research budget cuts. The visit provided good experience and demonstrated the importance to the sciences of active involvement in public policy.
Roger Guillory
Congratulations to Roger!!!
We are very pleased to learn that Roger has been selected to receive a 2017 National Science Foundation (NSF) Graduate Research Fellowship. This fellowship program is extremely competitive and we are very proud of Roger’s accomplishment. He has now full financial support for his PhD program for up to three years.
MSE C Journal
There has recently been great interest in developing bioabsorbable materials for small diameter arterial stents as a number of fully bioabsorbable polymeric stents have shown success in clinical trials. SURFI Team has been developing bioabsorbable stents based on zinc and demonstrated zinc’s ideal corrosion rate and behavior in the rat artery. The promise of a zinc-based stent is that it would retain the excellent mechanical properties that clinicians have come to expect from traditional stents (in contrast to the poor mechanical properties of polymeric stents), but would avoid the harmful chronic effects of the permanent implants (similar to degradable polymeric stents).
In the new paper entitled “Zn-Li Alloy after Extrusion and Drawing: Structural, Mechanical Characterization, and Biodegradation in Abdominal Aorta of Rat,” we describe the novel Zn-Li alloy formulated in our research project that was processed via extrusion and drawing in Germany, and then characterized, mechanically tested, and used in arterial implantation in rats from which biocompatibility and corrosion rate data were collected. Our new Zn-Li alloy generally came close to meeting material strength and elongation benchmarks, and their elastic ranges are comparable to Co-Cr-based alloys, making them very favorable for endovascular stent application. The Zn-Li material also exhibited acceptable compatibility with surrounding arterial tissue and our histopathological analysis failed to identify necrotic tissue in the samples examined.
Kevin Baker
Congratulations to our former graduate student, Kevin Baker (MS’2005), currently with Beaumont Hospital, who is the recipient of the 2017 Outstanding Young Alumni Award from the Board of Directors of Michigan Tech!
TMS
The 2017 TMS Annual Meeting took place in San Diego, CA, this year. The SURFI team was represented by Shan Zhao and Dr. Drelich. Shan presented a poster on Zn-Li alloy materials and their biocompatibility in endovascular environment. Dr. Drelich delivered two oral presentations. First presentation was on biodegradation and biocompatibility of Zn implants with nano-engineered surfaces and second one on antimicrobial ceramics. Dr. Drelich also chaired two sessions of the International Symposium entitled “Energy Technology” that he co-organized with Dr. Lei Zhang from the University of Alaska and a few others.
Finally, Dr. Drelich also proposed a new international symposium entitled “Biodegradable Materials for Medical Applications” to the TMS Biomaterials Committee, which was accepted and will take place during the 2018 TMS Annual Meeting in Phoenix, AZ.
Zn-Al: Strength and Elongation
Special high grade zinc and wrought zinc-aluminum (Zn-Al) alloys containing up to 5.5 wt% Al were processed, characterized, and implanted in rats in search of a new family of alloys with possible applications as bioabsorbable endovascular stents. The results of findings are published in the article entitled Evaluation of Wrought Zn-Al Alloys (1, 3, and 5 wt% Al) Through Mechanical and In Vivo Testing for Stent Applications published in the Journal of Biomedical Materials Research B: Applied Biomaterials.
These new bioalloys retained roll-induced texture with an anisotropic distribution of the second-phase Al precipitates following hot-rolling, and changes in lattice parameters were observed with respect to Al content. Mechanical properties for the alloys fell roughly in line with strength (190-240 MPa yield strength; 220-300 MPa ultimate tensile strength) and elongation (15-30%) benchmarks, and favorable elastic ranges (0.19-0.27%) were observed. Intergranular corrosion was observed during residence of Zn-Al alloys in the murine aorta, suggesting a different corrosion mechanism than that of pure zinc. This mode of failure needs to be avoided for stent applications because the intergranular corrosion caused cracking and fragmentation of the implants, although the composition of corrosion products was roughly identical between non- and Al-containing materials. In spite of differences in corrosion mechanisms, the cross-sectional reduction of metals in murine aorta was nearly identical at 30-40% and 40-50% after 4.5 and 6 months, respectively, for pure Zn and Zn-Al alloys Histopathological analysis and evaluation of arterial tissue compatibility around Zn-Al alloys failed to identify areas of necrosis, though both chronic and acute inflammatory indications were present.
Contact Angle
The rapid pace and shear number of papers published in recent years on contact angles, wetting, and non-wetting surfaces has lend itself to misconceptions and misuses of terminology, measurement techniques, and interpretation of experimental results. Terms describing contact angles, wettability, super-hydrophobicity and similar others terminology are loosely used. In a new contribution entitled Contact Angles and Wettability: Towards Common and Accurate Terminology and published in Surface Innovations, international team of experts led by Prof. A. Marmur from Israel defines key terms used in relation to contact angles. These terms are defined precisely based on the accumulative knowledge from the surface chemistry community over the last decades. The definitions provided are scientifically rigorous to avoid any ambiguity and confusion; the clarity of definitions should make data interpretation and comparison easier for future contributions to journals.
Shan Zhao
Congratulations to Shan!
She is a recipient of the Outstanding Scholarship Award in MSE Department recognizing her academic performance. She was nominated by department. A certificate of recognition for this award will be presented at the Graduate Research Colloquium Banquet on February 16.
Participants of Workshop
Dr. Drelich traveled to India and instructed a new course entitled “Contact Angles: Measurements, Interpretation and Modern Applications“ from January 29 to February 4. The course was offered to graduate students and postdoctoral fellows at the Indian Institute of Technology Madras (IIT Madras). Additionally, Dr. Drelich delivered a seminar on surface charge microscopy to faculty and students of IIT Madras.
Course Overview: Surfaces and coatings with controlled wetting characteristics have immense scientific and technological potential. Terms such as superhydrophobicity and superhydrophilicity were introduced to describe exceptionally weak and strong, respectively, interactions of materials and coatings with bulk water, controlled entirely by surface topography and material chemistry. Although manipulation of surface characteristics is nothing new, and was explored by the mineral processing and textile industries several decades ago, a renewed interest in surfaces/coatings of controlled wettability has been driven by an emerging market for products with engineered surfaces. Some common examples include water-repellant, snow- and ice-phobic products and formulations, water anti-fogging screens, windows and lenses, anti-fouling coatings, microfluidic devices, coatings for enhanced boiling heat transfer, foils for food packaging, and many others. The popularity of this sub-discipline of surface chemistry can also be attributed to the simplicity of contact angle measurements, although both measurements and interpretation of contact angles are often obfuscated by wide-spread misconceptions and misunderstandings. In this one-week course, the physics behind wetting phenomena on solid surfaces will be taught in detail, along with a discussion on new developments and modern applications of contact angle and wetting phenomena concepts. Course participants will learn these topics through lectures and case studies.
