Biomechanical Microsystems

This book presents the most important aspects of analysis of dynamical processes taking place on the human body surface. It provides an overview of the major devices that act as a prevention measure to boost a person‘s motivation for physical activity. A short overview of the most popular MEMS sensors for biomedical applications is given. The development and validation of a multi-level computational model that combines mathematical models of an accelerometer and reduced human body surface tissue is presented. Subsequently, results of finite element analysis are used together with experimental data to evaluate rheological properties of not only human skin but skeletal joints as well. Methodology of development of MOEMS displacement-pressure sensor and adaptation for real-time biological information monitoring, namely “ex vivo” and “in vitro” blood pulse type analysis, is described. Fundamental and conciliatory investigations, achieved knowledge and scientific experience about biologically adaptive multifunctional nanocomposite materials, their properties and synthesis compatibility, periodical microstructures, which may be used in various optical components for modern, productive sensors‘ formation technologies and their application in medicine, pharmacy industries and environmental monitoring, are presented and analyzed. This book also is aimed at research and development of vibrational energy harvester, which would convert ambient kinetic energy into electrical energy by means of the impact-type piezoelectric transducer. The book proposes possible prototypes of devices for non-invasive real-time artery pulse measurements and micro energy harvesting.

This volume presents a a selection of the papers presented at the 7th Italian Conference on Sensors and Microsystems, covering challenging topics on strategic areas as automotive, bio-sensors, fundamental chemistry for new generation of material for single molecule recognition.

This handbook focuses on the entire development process of biomedical microsystems that promote special interactions with cells. Fundamentals of cell biology and mechanobiology are described as necessary preparatory input for design tasks. Advanced design, simulation, and micro/nanomanufacturing resources, whose combined use enables the development of biomedical microsystems capable of interacting at a cellular level, are covered in depth. A detailed series of chapters is then devoted to applications based on microsystems that offer enhanced cellular control, including microfluidic devices for diagnosis and therapy, cell-based sensors and actuators (smart biodevices), microstructured prostheses for improvement of biocompatibility, microstructured and microtextured cell culture matrices for promotion of cell growth and differentiation, electrophoretic microsystems for study of cell mechanics, microstructured and microtextured biodevices for study of cell adhesion and dynamics, and biomimetic microsystems (including organs-on-chips), among others. Challenges relating to the development of reliable in vitro biomimetic microsystems, the design and manufacture of complex geometries, and biofabrication are also discussed.

This book is devoted to advanced materials and perspective sensors, which is one of the most important problems in nanotechnology and security. This book is useful for researchers, scientist and graduate students in the fields of solid state physics, nanotechnology and security.

This dissertation investigated the role of biomechanics in two physiological systems, the heart and bone. Biomechanics motivates the study and characterization of how cells sense external forces and convert these signals into an intracellular response in a process called mechanotransduction. Three independent studies were designed with the goal of applying mechanical forces that mimic the in vivo microenvironment of either the heart or bone. The aim of these studies was to better under the mechanisms driving cellular processes, including cardiac myocyte differentiation and osteoblast mechanotransduction. The first study presents the design and implementation of tissue engineering approach to stem cell-based myocardial therapy. Three dimensional engineered heart tissue was formed by suspending human embryonic stem cell-derived cardiac myocytes isolated from beating embryoid bodies in a soluble extracellular matrix, and an in vitro mechanical conditioning regimen was applied at physiological levels of myocardial strain. The viability of the engineered stem cell tissue was monitored in vitro and in vivo for up to 8 weeks using molecular imaging of reporter gene activity. The application of cyclic mechanical strain in vitro resulted in cellular alignment along the axis of strain and an elongated cellular morphology with a high nuclear to cytoplasmic ratio, typical of neonatal cardiac myocytes, as well as increased expression of cardiac troponin I, in comparison to static controls. Analysis of the in vitro and in vivo bioluminescence imaging data demonstrated the viability of engineered heart tissue constructs; however, histology results showed immature cells within the implanted constructs, suggesting an inability of the stem cell-derived cardiac precursors to maintain a cardiac phenotype in vivo, as well the inherent inefficiency of the beating embryoid body method to identify and isolate cardiac myocyte precursors. The functional shortcomings exhibited by the embryoid body-based differentiation of embryonic stem cell-derived cardiac myocytes in the first study motivated further refinement of cardiac myocyte differentiation techniques. Therefore, the second study executed the design and fabrication of a microelectromechanical platform to study the role of electrical and mechanical stimulation in cardiac myocyte differentiation. The fabrication process used a combination of soft lithography and traditional microfabrication techniques to pattern thin film metal electrodes on an elastomeric polymer membrane. The completed device enabled coupled characterization and imaging of cardiac myocytes precursors, and the ability to assess the range of mechanical forces, up to 10% equibiaxial strain, that may induce or maintain a cardiac fate. Electrical continuity was demonstrated under static conditions but not under strain, and improvements in metal deposition and adhesion could address this performance defect. Beating clusters containing human embryonic stem cell-derived cardiac myocytes were plated on fabricated membranes, uncoated and coated with Matrigel, and cell viability was monitored using contrast microscopy. The third study transitioned to a different mechanical model of physiological forces, which was the application of oscillatory fluid flow-mediated fluid shear stress generated by the loading and unloading of bone. Specifically, the role of focal adhesion kinase, a protein tyrosine kinase recruited at focal adhesions and a major mediator of integrin signaling pathways, was studied in osteoblast mechanotransduction. The biochemical and transcriptional response of focal adhesion kinase mutant osteoblasts to physiological levels of shear stress induced by oscillatory fluid flow was impaired as measured by prostaglandin E2 release and cyclooxygenase-2 gene expression. Restoration of focal adhesion kinase expression with site-specific mutations at two tyrosine phosphorylation sites demonstrated that phosphorylation events play a role in prostaglandin release following oscillatory fluid flow. In conclusion, the role of mechanical forces, including the effect of cyclic mechanical strain in human embryonic stem cell-derived cardiac myocyte tissue engineering and the fluid shear stress-induced response of focal adhesion kinase mutant osteoblasts, was successfully demonstrated and quantified in this dissertation.

The classic textbook on comparative biomechanics—revised and expanded Why do you switch from walking to running at a specific speed? Why do tall trees rarely blow over in high winds? And why does a spore ejected into air at seventy miles per hour travel only a fraction of an inch? Comparative Biomechanics is the first and only textbook that takes a comprehensive look at the mechanical aspects of life—covering animals and plants, structure and movement, and solids and fluids. An ideal entry point into the ways living creatures interact with their immediate physical world, this revised and updated edition examines how the forms and activities of animals and plants reflect the materials available to nature, considers rules for fluid flow and structural design, and explores how organisms contend with environmental forces. Drawing on physics and mechanical engineering, Steven Vogel looks at how animals swim and fly, modes of terrestrial locomotion, organism responses to winds and water currents, circulatory and suspension-feeding systems, and the relationship between size and mechanical design. He also investigates links between the properties of biological materials—such as spider silk, jellyfish jelly, and muscle—and their structural and functional roles. Early chapters and appendices introduce relevant physical variables for quantification, and problem sets are provided at the end of each chapter. Comparative Biomechanics is useful for physical scientists and engineers seeking a guide to state-of-the-art biomechanics. For a wider audience, the textbook establishes the basic biological context for applied areas—including ergonomics, orthopedics, mechanical prosthetics, kinesiology, sports medicine, and biomimetics—and provides materials for exhibit designers at science museums. Problem sets at the ends of chapters Appendices cover basic background information Updated and expanded documentation and materials Revised figures and text Increased coverage of friction, viscoelastic materials, surface tension, diverse modes of locomotion, and biomimetics

For decades, people have searched for ways to harvest energy from natural sources. Lately, a desire to address the issue of global warming and climate change has popularized solar or photovoltaic technology, while piezoelectric technology is being developed to power handheld devices without batteries, and thermoelectric technology is being explored to convert wasted heat, such as in automobile engine combustion, into electricity. Featuring contributions from international researchers in both academics and industry, Energy Harvesting with Functional Materials and Microsystems explains the growing field of energy harvesting from a materials and device perspective, with resulting technologies capable of enabling low-power implantable sensors or a large-scale electrical grid. In addition to the design, implementation, and components of energy-efficient electronics, the book covers current advances in energy-harvesting materials and technology, including: High-efficiency solar technologies with lower cost than existing silicon-based photovoltaics Novel piezoelectric technologies utilizing mechanical energy from vibrations and pressure The ability to harness thermal energy and temperature profiles with thermoelectric materials Whether you’re a practicing engineer, academician, graduate student, or entrepreneur looking to invest in energy-harvesting devices, this book is your complete guide to fundamental materials and applied microsystems for energy harvesting.