http://s.uconn.edu/meseminar1/28/22

Abstract: Bone is strong, tough yet lightweight, which can be attributed to its complex hierarchical structures across multiple length scales. The factors contributing to these superior properties are still not completely understood, especially its structure at the sub-micron- and nano-scales. The morphology and mechanical properties of bone are also affected by diseases and treatment. This study presents the results of combined experimental and computational studies of the mechanical behaviors and structures of bone across multiple length scales. Mechanical testing coupled with micro X-ray computed tomography (micro-CT) enabled concurrent non-invasive characterization of 3D full-field bone microstructures and bone mechanical properties. Atomic force microscopy (AFM) was used to map the surface morphology and elastic properties of microscale structures (cement line and sub-lamellae) and nanoscale ultrastructure (mineralized collagen fibril (MCF) and extrafibrillar matrix (EFM)) in bone. The experimental results are integrated with computational models. The results provided a better understanding of the structure and the mechanical behaviors of bone across multiple length scales, laid the foundation for the bio-inspired design of new materials, and shed light on the improvement of implant treatment.

 

Biographical Sketch: Dr. Jing Du is an Assistant Professor of Mechanical Engineering at Penn State University. She received her B.S. and M.S. degrees in Mechanical Engineering and Materials Science and Engineering, respectively, from Tsinghua University and a Ph.D. degree in Mechanical and Aerospace Engineering from Princeton University. Before joining Penn State, she was a postdoctoral scholar in the School of Dentistry at the University of California, San Francisco (UCSF). Her current areas of research interests include mechanical behaviors of biological tissues and biomaterials, biomedical devices, and bio-inspired design.

http://s.uconn.edu/meseminar1/21/22

Abstract: Recent advances in electronics enable powerful biomedical devices that have greatly reduced therapeutic risks by monitoring vital signals and providing means of treatment.  Conventional electronics today form on the planar surfaces of brittle wafer substrates and are not compatible with complex body tissues.  Soft and implantable devices can help us better understand the behavior and effects of various diseases.  This talk presents the challenges, design strategies, and novel fabrication processes behind a potential medical device that (a) integrates with human physiology, and (b) dissolves completely after its effective operation.  The integration of the deformable multimodal sensing platform with stretchable antennas, micro-supercapacitor arrays, and energy harvesting modules further yields a self-powered stretchable wireless sensing system for next-generation bio-integrated electronics and environmental sensing.

Biographical Sketch: Dr. Huanyu “Larry” Cheng is an Assistant Professor of Engineering Science and Mechanics with courtesy appointments in the Department of Biomedical Engineering, Department of Mechanical Engineering, Department of Architectural Engineering, Department of Industrial and Manufacturing Engineering, and the Department of Materials Science and Engineering at Penn State University. His research group focuses on the design, fabrication, and application of stretchable and dissolvable multimodal sensors for biomedicine. Larry has co-authored more than 100 peer-reviewed publications with total citations >13,000 and an H-index of 46 according to Google Scholar. His work has been recognized through the reception of numerous awards, including the 2022 Minerals, Metals & Materials Society (TMS) Functional Materials Division (FMD) Young Leaders Professional Development Award, the 2021 NIH Trailblazer Award, 2021 Scialog Fellow in Advancing BioImaging, 2021 Frontiers of Materials Award from TMS, First and Second Place in the Ben Franklin TechCelerator Pitch in 2020 and 2021, respectively, ACS Petroleum Research Fund New Investigator in 2018, Forbes 30 Under 30 Science category in 2017, elected member of the Global Young Academy for scientists under age 40 in 2016, among others. He also serves as the associate editor for 7 journals and reviewer for 185 international journals.

http://s.uconn.edu/meseminar12/10/21

Abstract: Hydrogels, highly hydrated cross-linked polymer networks, have emerged as powerful synthetic analogs of extracellular matrices for basic cell studies as well as promising biomaterials for regenerative medicine applications. A critical advantage of these synthetic matrices over natural networks is that bioactive functionalities, such as cell adhesive sequences and growth factors, can be incorporated in precise densities while the substrate mechanical properties are independently controlled. We have engineered poly(ethylene glycol) [PEG]-maleimide hydrogels for local delivery of therapeutic proteins and cells in several regenerative medicine applications. For example, synthetic hydrogels with optimal biochemical and biophysical properties have been engineered to direct human stem cell-derived intestinal organoid growth and differentiation, and these biomaterials serve as injectable delivery vehicles that promote organoid engraftment and repair of intestinal wounds. In another application, hydrogels presenting immunomodulatory proteins induce immune acceptance of allogeneic pancreatic islets and reverse hyperglycemia in models of type 1 diabetes. Finally, injectable hydrogels delivering anti-microbial proteins eradicate bone-associated bacterial infections and support bone repair. These studies establish these biofunctional hydrogels as promising platforms for basic science studies and biomaterial carriers for cell delivery, engraftment and enhanced tissue repair.

Biographical Sketch: Andrés J. García is the Executive Director of the Petit Institute for Bioengineering and Bioscience and Regents’ Professor at the Georgia Institute of Technology. Dr. García’s research program integrates innovative engineering, materials science, and cell biology concepts and technologies to create cell-instructive biomaterials for regenerative medicine and generate new knowledge in mechanobiology. This cross-disciplinary effort has resulted in new biomaterial platforms that elicit targeted cellular responses and tissue repair in various biomedical applications, innovative technologies to study and exploit cell adhesive interactions, and new mechanistic insights into the interplay of mechanics and cell biology. In addition, his research has generated intellectual property and licensing agreements with start-up and multi-national companies. He is a co-founder of 3 start-up companies (CellectCell, CorAmi Therapeutics, iTolerance). He has received several distinctions, including the NSF CAREER Award, Young Investigator Award from the Society for Biomaterials, Georgia Tech’s Outstanding Interdisciplinary Activities Award, the Clemson Award for Basic Science from the Society for Biomaterials, the International Award from the European Society for Biomaterials, and Georgia Tech’s Class of 1934 Distinguished Professor Award. He is an elected Fellow of Biomaterials Science and Engineering (by the International Union of Societies of Biomaterials Science and Engineering), Fellow of the American Association for the Advancement of Science, Fellow of the American Society of Mechanical Engineers, and Fellow of the American Institute for Medical and Biological Engineering. He served as President for the Society for Biomaterials in 2018-2019. He is an elected member of the National Academy of Engineering, the National Academy of Medicine, and the National Academy of Inventors.

http://s.uconn.edu/meseminar12/3/21

Abstract: Internet of things (IoT), robotics, big data and artificial intelligence (AI) hold the key to Industry 4.0, which is identified as cyber-physical systems. To stay relevant in the AI age, humans must collaborate with robots or even merge with electronics and machines to realize internet of health (IoH), augmented reality (AR), and augmented human capabilities. However, bio-tissues are soft, curvilinear and dynamic whereas conventional electronics and machines are hard, planar, and rigid. Over the past two decades, soft electronics blossom as a result of new materials, novel structural designs, and digital manufacturing processes. This talk will discuss our research on the design, fabrication, conformability, and functionality of soft bio-integrated and bio-mimetic electronics based on inorganic functional materials such as metals, silicon, carbon nanotubes (CNT), and graphene. In particular, epidermal electronics, a.k.a. electronic tattoos (e-tattoos) represent a class of noninvasive stretchable circuits, sensors, and stimulators that are ultrathin, ultrasoft and skin-conformable. My group has invented a dry and freeform “cut-solder-paste” method for the rapid prototyping of multimodal, wireless, or very large area e-tattoos that are also high-performance and long-term wearable. The e-tattoos can be applied for physiological sensing and prosthesis/robot control. Recently, we have also engineered e-skins based on electrically conductive porous nanocomposite. The hybrid piezoresistive and piezocapacitive responses of this novel e-skin has enabled high pressure sensitivity over wide pressure ranges. It therefore could be applied for not only mechanophysiological sensing, but also soft robotics undergoing large deformations. A perspective on future opportunities and challenges in this field will be offered at the end of the talk.

 Biographical Sketch: Dr. Nanshu Lu is currently Temple Foundation Endowed Associate Professor at the University of Texas at Austin. She received her B.Eng. from Tsinghua University, Beijing, Ph.D. from Harvard University, and then Beckman Postdoctoral Fellowship at UIUC. Her research concerns the mechanics, materials, manufacture, and human / robot integration of soft electronics. She has been named 35 innovators under 35 by MIT Technology Review (TR 35). She has received US NSF CAREER Award, US ONR and AFOSR Young Investigator Awards, 3M non-tenured faculty award, and iCANX/ACS Nano Inaugural Rising Star Lectureship. She has been selected as one of the five great innovators on campus and five world-changing women at the University of Texas at Austin. She is named a highly cited researcher by Web of Science. For more information, please visit Prof. Lu’s research group webpage at https://sites.utexas.edu/nanshulu/.

http://s.uconn.edu/meseminar11/12

Abstract: This talk presents a manufacturability-driven, multi-component topology optimization (MTO) framework for simultaneous design and partitioning of structures assembled of multiple components. Constraints on component geometry imposed by chosen manufacturing processes are incorporated in the conventional density-based topology optimization, with additional design variables specifying fractional component membership that enables continuous relaxation of otherwise discrete partitioning problems.  The geometric constraints imposed by various manufacturing processes, such as size, perimeter length, undercut, and enclosed cavities, are also relaxed to enable the manufacturability evaluation of “gray” geometries that occur during the density-based topology optimization. Examples on minimum compliance structural assembly design for sheet metal stamping (MTO-S), die casting (MTO-D), additive manufacturing (MTO-A), and continuous fiber printing process (MTO-C) show promising advantages over the conventional monolithic topology optimization.  In particular, manufacturing constraints previously applied to monolithic topology optimization gain new interpretations when applied to multi-component assemblies, which can unlock richer design space for topology exploration.  The talk will conclude with a brief overview of the latest developments towards the MTO framework for foldable “4D” printed structures.

Biographical Sketch: Kazuhiro Saitou is a Professor of Mechanical Engineering at the University of Michigan, Ann Arbor, Michigan, USA. He currently serves for the Department as an Associate Chair for Graduate Education. He received BEng degree from University of Tokyo, Japan, and MS and PhD degrees from the Massachusetts Institute of Technology (MIT), USA. His research interest includes algorithmic and computational design synthesis and design for manufacture and assembly, with applications in mechanical, industrial, and biomedical systems.  He is a Fellow of ASME and IEEE.

http://s.uconn.edu/meseminar11/19/21

Password: 1234

Abstract: I will provide an account of the interesting dynamics exhibited by droplets at multiple length and time scales in completely different domains, namely gas turbines and COVID-19. In the first part of my talk, I will provide some insights into the dynamics of spray-swirl interaction with particular focus on droplet transport, breakup and dispersion. I will show how the fundamental insights gained through such interactions can be used to design a new class of atomizers in gas turbines. In the second part of my talk, I will discuss how the spread of COVID can happen through respiratory droplets and fomites. In this part, I will provide a detailed exposition of how respiratory droplet dynamics can be combined with a pandemic model to provide a first principle insights into infection spread rates. We will show through experiments using surrogate fluids how such models can be experimentally verified rigorously. Subsequently, I will show how fomites form and how the virions are embedded in the crystal network using both contact free as well as sessile droplets.

 

Biographical Sketch: Prof. Saptarshi Basu is currently DRDO Chair Professor in the department of mechanical engineering at IISc. Prof. Basu primarily works on multiphase systems, especially droplets at multiple length and timescales across multiple application domains. He is a fellow of Indian National Academy of Engineering, ASME, Institute of Physics, Royal Aeronautical Society and Royal Society of Chemistry. Prof. Basu is the recipient of DST Swarnajayanti Fellowship in engineering.   

http://s.uconn.edu/meseminar11/5/21

Abstract: While there is significant interest in using tissue engineering techniques to create tendon and ligament replacements, no engineered biomaterial has been successful in replicating their physiological function. This is because there is a fundamental lack of understanding of how to produce a robust tensile load-bearing biological tissue. Previous work suggests that tendon maturation is driven by rapid increases in collagen fibril length and molecular crosslinking mediated by mechanical stimulation due to muscle activity. However, the effect of mechanical stimulation on the tensile mechanics of developing tendons and the functional significance of the structural changes that occur during development are still unclear. To address this knowledge gap, we investigated the multiscale structure-function relationships of embryonic tendons during normal development and following the loss of mechanical stimulation via immobilization. Using multiscale mechanical testing, we found that the strain transmitted to the collagen fibrils in tendons at embryonic days 16, 18, and 20 is less than the strain applied to the tissue, suggesting the collagen fibrils remain discontinuous throughout embryonic development. However, the ratio of the fibril strains to the tissue strains increased with developmental age; this indicates that more strain is being transmitted to the fibrils and that there is less interfibrillar sliding, which is consistent with an increase in the average fibril length and an increase in the macroscale mechanics during this period of development. Additionally, there was a decrease in the macroscale tensile modulus and the fibril: tissue strain ratio with flaccid (but not rigid) immobilization, suggesting that complete loss of mechanical stimulation inhibits fibril elongation and strain transmission to the collagen fibrils, resulting in impaired functional maturation. Consistent with these mechanical assessments, we found that collagen fibril bundling was impaired with immobilization. Interestingly, while the enthalpy required to denature the tendons increased with increasing age, there was no effect with immobilization. This suggests that although intermolecular crosslinks in embryonic tendons increase with development, the loss of tensile mechanical properties with immobilization is potentially not due to a reduction in functional crosslinking. Together, these data suggest that the key structural change induced by mechanical stimulation during tendon development is an increase in the strain transmitted to the collagen fibrils, which is consistent with fibril elongation. These data provide fundamental insight into the mechanisms driving tendon development and will guide the design of improved techniques for engineering tendon/ligament replacements.

 

Biographical Sketch: Dr. Szczesny is an Assistant Professor at the Pennsylvania State University with a joint appointment in the Departments of Biomedical Engineering and Orthopaedics & Rehabilitation. He completed his postdoctoral training in 2017 as an NIH NRSA F32 Fellow and obtained a PhD in bioengineering in 2015 at the University of Pennsylvania. Prior to his doctorate, Dr. Szczesny developed medical implants as a design engineer for Aesculap Implant Systems and as a research assistant at the Helmholtz Institute for Biomedical Technology in Aachen, Germany. He obtained a MS in mechanical engineering at the Massachusetts Institute of Technology in 2005 and a BS in mechanical engineering at the University of Pennsylvania in 2003. In recognition of his contribution to the field of tendon biomechanics and mechanobiology, Dr. Szczesny was an ORS New Investigator Recognition Award (NIRA) finalist, won 1st place in the SB3C PhD competition (twice), and received the 2015 Acta Student Award. Dr. Szczesny’s current research examines how cells in tendon sense the mechanics of their local microenvironment (e.g., strains, stiffness) and how their response drives changes in tissue mechanical properties during tendon degeneration, repair, and development. The ultimate goals of this work are to identify the causes of tendon pathology, discover novel therapeutic options, and direct the design of biomaterials that can recapitulate the behavior of native tissue.

http://s.uconn.edu/meseminar10/29/21

 Abstract: Redox flow batteries (RFBs) are an emerging energy storage technology that offers unique advantages for long-duration, grid-scale energy storage due to their ability to decouple energy and power ratings and the associated unprecedented scalability. Despite their promise, the relatively higher capital cost of RFBs limits their commercial viability and widespread adoption. One possible approach to reduce the capital cost is to improve the performance (i.e., increased energy and/or power density) of state-of-the-art systems for less material use, which consequently reduces cell costs. In this talk, an overview of the presenter’s most recent research toward high-performance RFBs will be given. In particular, the following three research projects will be summarized:

1. Natural selection as a toolkit to overcome practical limitations in non-aqueous redox flow batteries (NRFB) – The performance characteristics of the mushroom inspired NRFB electrolyte using a suite of electrochemical and operando spectro-electrochemical data will be reported.
2.  Overcoming the active material solubility limitation in RFBs via redox-targeting reactions – Recent efforts to reveal the fundamental principles of indirect redox-targeting reactions necessary to enable the rational design of high-energy density RFBs will be presented.
3. Manufacturing of fabric-electrodes using machine learning based screening platforms – Critical factors underpinning electrode performance are elucidated. The structure-property-performance linkages of commercially available electrodes will be discussed.

 

Biographical Sketch: Dr. Ertan Agar is an Assistant Professor in the Department of Mechanical Engineering and the director of Electrochemical Energy Systems and Transport Laboratory (E2STL) at the University of Massachusetts Lowell. He earned his Ph.D. degree in Mechanical Engineering from Drexel University. His Ph.D. dissertation work was a combined experimental and modeling effort, which was aimed at understanding the species transport mechanisms governing capacity fade in vanadium redox flow batteries. Following his doctoral studies, Dr. Agar worked as a post-doctoral researcher in the Chemical Engineering Department at Case Western Reserve University. In this role, he worked on performance diagnostics of flowable slurry electrodes. His research interest includes design and diagnostics of flow-assisted electrochemical systems for energy and water applications (e.g., redox flow batteries, photoelectrochemical storage and water treatment cells), mass/charge transport phenomena, and electrochemical reaction kinetics. Dr. Agar is an active member of the Electrochemical Society and International Society of Electrochemistry. He also serves as the Faculty Lead for the UML I-Corps Site Program and the Regional Northeast I-Corps Hub.