Toward Long-Endurance Flight- Tamkang’s Aspect of Micro Ornithopters

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Microfabricated platforms to investigate cell mechanical properties

Mechanical stimulation has been imposed on living cells using several approaches. Most early investigations were conducted on groups of cells, utilizing techniques such as substrate deformation and flow-induced shear. To investigate the properties of cells individually, many conventional techniques were utilized, such as AFM, optical traps/optical tweezers, magnetic beads, and micropipette aspiration. In specific mechanical interrogations, microelectro- mechanical systems (MEMS) have been designed to probe single cells in different interrogation modes. To exert loads on the cells, these devices often comprise piezo-electric driven actuators that attach directly to the cell or move a structure on which cells are attached. Uniaxial and biaxial pullers, micropillars, and cantilever beams are examples of MEMS devices. In this review, the methodologies to analyze single cell activity under external loads using microfabricated devices will be examined. We will focus on the mechanical interrogation in three different regimes: compression, traction, and tension, and discuss different microfabricated platforms designed for these purposes

Climbing and Walking Robots

Nowadays robotics is one of the most dynamic fields of scientific researches. The shift of robotics researches from manufacturing to services applications is clear. During the last decades interest in studying climbing and walking robots has been increased. This increasing interest has been in many areas that most important ones of them are: mechanics, electronics, medical engineering, cybernetics, controls, and computers. Today’s climbing and walking robots are a combination of manipulative, perceptive, communicative, and cognitive abilities and they are capable of performing many tasks in industrial and non- industrial environments. Surveillance, planetary exploration, emergence rescue operations, reconnaissance, petrochemical applications, construction, entertainment, personal services, intervention in severe environments, transportation, medical and etc are some applications from a very diverse application fields of climbing and walking robots. By great progress in this area of robotics it is anticipated that next generation climbing and walking robots will enhance lives and will change the way the human works, thinks and makes decisions. This book presents the state of the art achievments, recent developments, applications and future challenges of climbing and walking robots. These are presented in 24 chapters by authors throughtot the world The book serves as a reference especially for the researchers who are interested in mobile robots. It also is useful for industrial engineers and graduate students in advanced study

Bio-mechanical Characterization of Adherent Cell Layers with a PDMS Cantilever

In the last few decades, the mechanical characteristics of human cells has been linked to many physiological processes and pathological conditions, illustrating the importance as effective biomarkers. Mounting research has shown the mechanical force between cells and the extracellular matrix (ECM) plays a vital role in cellular processes such as tissue homeostasis, wound healing, cancer metastasis, and the progression of various diseases. This mechanical force, or the force that a cell produces on its surroundings, is termed as the cellular traction force (CTF). Precise characterization of the CTF can expand our knowledge of these important cellular processes as well as lead to the development of novel mechanical biomarkers of various cellular disorders. Current methods to measure the CTF require special substrates and fluorescent microscopy, rendering them less suitable in a clinical setting. This study details the development of a novel method to measure the CTF that is more affordable and accessible in a clinical setting than conventional approaches. The developed device, an ultrathin polydimethylsiloxane (PDMS) cantilever, demonstrated a rapid and direct approach to measure the combined CTF of a large population of cells. The CTF of benign and aggressive breast cancer cell lines were measured. The device was then used to measure the CTF of NIH/3T3 fibroblasts while their cytoskeletal network was altered. In addition, the CTF and the dynamic contraction force of live rat cardiomyocytes were characterized. Lastly, the combination of the thin film PDMS cantilever and beating cardiomyocytes created a self-propelled swimming biorobot

Design for an Increasingly Protean Machine

Data-driven, rather than hypothesis-driven, approaches to robot design are becoming increasingly widespread, but they remain narrowly focused on tuning the parameters of control software (neural network synaptic weights) inside an overwhelmingly static and presupposed body. Meanwhile, an efflorescence of new actuators and metamaterials continue to broaden the ways in which machines are free to move and morph, but they have yet to be adopted by useful robots because the design and control of metamorphosing body plans is extremely non-intuitive. This thesis unites these converging yet previously segregated technologies by automating the design of robots with physically malleable hardware, which we will refer to as protean machines, named after Proteus of Greek mythology. This thesis begins by proposing an ontology of embodied agents, their physical features, and their potential ability to purposefully change each one in space and time. A series of experiments are then documented in which increasingly more of these features (structure, shape, and material properties) were allowed to vary across increasingly more timescales (evolution, development, and physiology), and collectively optimized to facilitate adaptive behavior in a simulated physical environment. The utility of increasingly protean machines is demonstrated by a concomitant increase in both the performance and robustness of the final, optimized system. This holds true even if its ability to change is temporarily removed by fabricating the system in reality, or by “canalization”: the tendency for plasticity to be supplanted by good static traits (an inductive bias) for the current environment. Further, if physical flexibility is retained rather than canalized, it is shown how protean machines can, under certain conditions, achieve a form of hyper-robustness: the ability to self-edit their own anatomy to “undo” large deviations from the environments in which their control policy was originally optimized. Some of the designs that evolved in simulation were manufactured in reality using hundreds of highly deformable silicone building blocks, yielding shapeshifting robots. Others were built entirely out of biological tissues, derived from pluripotent Xenopus laevis stem cells, yielding computer-designed organisms (dubbed “xenobots”). Overall, the results shed unique light on questions about the evolution of development, simulation-to-reality transfer of physical artifacts, and the capacity for bioengineering new organisms with useful functions

3D bioprinted heart patches for cardiac regeneration

BACKGROUND: epicardial patch transplantation is a promising approach to restore some of the cardiac function lost after myocardial infarction (MI). Advances in 3D bioprinting, 3D cell culture and transplantation methods at surgery have provided hope that this approach could soon benefit heart failure patients. The optimal content of 3D bioprinted patches (the “bioink” extruded by a 3D bioprinter) is not known. Patches containing a suspension of 3D vascularised cardiac spheroids (VCS; 3D aggregates of cells / microtissues) in hydrogel may confer an advantage compared to freely suspended cells or hydrogel without cells. The mechanisms underlying the benefit of epicardial patch transplantation approaches have not been fully elucidated and this is needed for widespread clinical translation. To be fully compatible with cardiothoracic surgical approaches in future, patches should be transplantable by minimally invasive robotic approaches. METHOD: Alginate-gelatin (AlgGel) patches were optimised ex vivo for cardiac applications, followed by in vivo transplantation of patches in mice modelling MI. For the ex vivo optimisation phase, three different bioprinters were used to bioprint patches with different bioink contents which were incubated up to 28 days and analysed. For the in vivo phase, new patches were 3D bioprinted using the optimal methods determined in the previous (ex vivo) experiments and surgically transplanted to the epicardium in infarcted mice. For these in vivo experiments, we cultured mixed cardiac cells: induced pluripotent stem cell derived cardiomyocytes (iCMs), human coronary artery endothelial cells (HCAECs) and cardiac fibroblasts (CFs). Cells were cultured using hanging drops to generate VCS which were suspended in AlgGel to create bioink for 3D bioprinting of patches. Study control groups (in vivo) were: the same cells freely suspended in AlgGel, AlgGel without cells, MI without treatment and sham surgery (no MI and no treatment). The primary outcome was cardiac function (left ventricular ejection fraction, LVEF%) measured up to day 28 post surgery. Additional analyses included: electrical mapping, histology, cell quantification by flow cytometry and mRNA (gene expression) profiling. Alongside these experiments, we developed novel surgical robotic minimally invasive instruments designed to transplant similar patches at human scale. We prototyped a heart patch transplanter device and demonstrated its potential utility in a world-first operation on a pig cadaver. RESULTS: Ex vivo patches incubated for 28 days allowed for self-organisation of endothelial cells into networks and contractile activity within patches. In vivo transplantation of patches in mice modelling MI resulted in a “return to baseline” improvement in median LVEF%. Our results measured median baseline (pre-surgery) LVEF% for all mice at 66%. Post-surgery, LVEF% was 58% for Sham (non-infarcted) and 41% for MI (no treatment) mice. Patch transplantation increased LVEF%: 55% (acellular; p=0.012), 59% (cells; p=0.106), 64% (spheroids; p=0.010). The VCS group was associated with improved electrical mapping profiles, lower infarct sizes, changes in host immune cell numbers and a gene expression (mRNA) profile which was closest to sham mice (with no MI). As proof-of-concept, similar scaled-up AlgGel patches were successfully transplanted in a porcine cadaver using a prototyped robotic minimally invasive surgical instrument. CONCLUSION: Epicardial transplantation of patches improves cardiac function in mice modelling MI. The use of VCS in alginate-gelatin bioink seems to offer advantages compared to freely suspended cells or hydrogel alone. The fact that hydrogel alone without cells confers some restoration of myocardial function suggests that the mechanism is not fully accounted for by the cellular portion of the bioink. Further studies are needed with a focus on whether host immune cell modulation is a key mechanism underlying the benefit of this approach. Since our most successful treatment group (VCS) had a similar transcriptome compared to non-infarcted (sham) mice, further studies should also include transcriptomic analyses to confirm reproducibility of this finding. If it is confirmed that immuno-genetic mechanisms underly patch-based approaches to myocardial protection after MI, this may change the focus of treatment strategies and avoid wasted resources and potentially patient harm (from treatments which are not aligned with the underlying mechanism). Our robotic minimally invasive patch transplantation operation represents a first step on a potential pathway towards transplantation at human surgery (without the need for traditional open surgery). For translatability, patch development should work towards being compatible with robotic and/or minimally invasive transplantation

STEM Undergraduate Research Symposium 2017 Full Program

Full program of the 2017 LSSF STEM Undergraduate Research Conference

Raman Scattering:From Structural Biology to Medical Applications

This is a review of relevant Raman spectroscopy (RS) techniques and their use in structural biology, biophysics, cells, and tissues imaging towards development of various medical diagnostic tools, drug design, and other medical applications. Classical and contemporary structural studies of different water-soluble and membrane proteins, DNA, RNA, and their interactions and behavior in different systems were analyzed in terms of applicability of RS techniques and their complementarity to other corresponding methods. We show that RS is a powerful method that links the fundamental structural biology and its medical applications in cancer, cardiovascular, neurodegenerative, atherosclerotic, and other diseases. In particular, the key roles of RS in modern technologies of structure-based drug design are the detection and imaging of membrane protein microcrystals with the help of coherent anti-Stokes Raman scattering (CARS), which would help to further the development of protein structural crystallography and would result in a number of novel high-resolution structures of membrane proteins—drug targets; and, structural studies of photoactive membrane proteins (rhodopsins, photoreceptors, etc.) for the development of new optogenetic tools. Physical background and biomedical applications of spontaneous, stimulated, resonant, and surface- and tip-enhanced RS are also discussed. All of these techniques have been extensively developed during recent several decades. A number of interesting applications of CARS, resonant, and surface-enhanced Raman spectroscopy methods are also discussed

The 26th Annual Boston University Undergraduate Research (UROP) Abstracts

The file is available to be viewed by anyone in the BU community. To view the file, click on "Login" or the Person icon top-right with your BU Kerberos password. You will then be able to see an option to View.Abstracts for the 2023 UROP Symposium, held at Boston University on October 20, 2023 at GSU Metcalf Ballroom. Cover and logo design by Morgan Danna. Booklet compiled by Molly Power