Mechanical engineering, with its scientific theories and mathematical analysis methods, have found itself in other disciplines and has become an essential core in understanding several problems. One of those disciplines is medicine and biology.
What does mechanics serve as other technologies, particularly medical and biological sciences? Mechanical engineering covers a wide variety of subjects and its relation to medical technologies started when engineers wanted to use mechanical engineering principles to solve certain problems in medicine.
These technologies range from small individual parts to large systems that can be involved in almost every aspect of technology. Mechanical engineering covers topics related to energy, fluid mechanics, dynamics, robotics, solid mechanics, heat transfer, design and manufacturing, maintenance and control. This diverse background helps mechanical engineers, as well as scientists in the mechanical field, to play a critical role in solving global issues and challenges of many areas of interest outside mechanical technologies.
Medical areas such as pharmacokinetics and pharmacodynamics would not have emerged without the principles of mechanical engineering. In fact, mechanical engineering principles are now deemed fundamental in the understanding areas in immunology, orthopedics and cardiovascular physiology. The combination of new techniques and disciplines have paved the way for the merging of mechanical engineering and medicine. Such notion would be hard to imagine two decades ago.
Biomechanics is the application of mechanical principles in the study of living organisms including their kinematics (description of motion) and kinetics (actions of forces associated with motion), it views the human body as a collection of levers, made of bones which are moved by its muscles. In sport and exercise, where mechanics can be involved to analyze the performance of athletes based on their interaction with the equipment.
According to the scale in which the study or the application is done, we can distinguish between biomechanics and mechanobiology. Biomechanics focuses more on body segments and its interaction with the surrounding environment while mechanobiology is concerned more with the level of cells — it dwells on the behavior of physical forces and transfer in cell and/or tissues.
Nanotechnology is the understanding the behavior of matter at infinitesimal dimensions called nanometers (a nanometer is one-billionth of a meter; a human hair is about 75000 nanometers in diameter), where incredible properties enable emergent applications. Considering combination between nanoscale science, engineering, and technology, nanotechnology covers sensing, imaging, measuring, manufacturing, control and manipulating nanoscale matter. In mechanics, the integration of nanotechnology is focused on three main topics including nanostructures (carbon nanotubes), Nano-fluids and microfluidics, and nanorobotics. In following, we present the application of these Nano-mechanics topics in medicine and biology.
Carbon nanotubes (CNTs) are nanoscale structures made of pure carbon that are long and thin and shaped like tubes. These molecules are same sized and structured in chemical bonding and aligned by Van der Walls forces into ropes. The length of CNTs can reach a few millimeters while its diameter is in the order of a few nanometers.
Cancer is arguably one of the most complicated diseases in the world. World Health Organization (WHO) declares cancer as one of the main causes of morbidity and mortality worldwide, with approximately 14 million cases in 2012. Anticancer drugs like Chemotherapy or Radiotherapy often have physiological, biochemical and cellular toxic side effects. Several methods in many fields, including carbon nanotubes, is a subject of many efforts to reduce this problem. Carbon nanotubes have unique mechanical properties that strongly minimize the effects of many therapeutics.
Taxoid is a chemotherapeutic agent to block proliferating cancer cells. Carbon nanotubes have been explored as a tool in nanocarriers for the exploration of novel drugs. There are large varieties of nanoscale drug delivery vectors like single-walled carbon nanotubes (SWCNTs). As CNTs are needle-like shape, they have been involved in injection and integration into target cells. Also, CNTs are combined with the anticancer agent toxoid as a cleavable linker. In order to ensure the target cell, the drug is transported via endocytosis and released into the cell. Microtubules interact with the drug as evaluated by flow cytometry thus formatting a stable microtubule-toxoid complex.
Another novel application of carbon nanotubes is a drug delivery method called smart drug delivery. This is a method of high recognition of cancer cells or cancer tissues in order to deliver medication with high precision. It is efficient for the lymphatic system; metastases of certain cancers can be effectively inhibited by subcutaneous injection. Adsorption on the PAA-CNT surface is possible through coprecipitation of Fe3O4-based magnetic nanoparticles, polyacrylic acid (PAA) can be added to CNTs to become highly hydraulic.
In the “longboat” anticancer system, carbon nanotubes are used for cancer treatment based on a functionalized single-walled nanotube attached to a complex mixture of cisplatin and folic acid derivative via covalent or noncovalent bonding to comprise the “longboat” which has been reported to be taken up by cancer cells via endocytosis.
Computational Fluid Dynamics
Another area where mechanics show promise in medicine is computational fluid dynamics. Computational fluid dynamics (CFD) is an engineering tool that connects mechanics to mathematics and software programming to execute simulation performing how a fluid (liquid or gas) flows based on Navier-Stokes equations which are the main mathematical formulation modeling all phenomena of fluid mechanics.
The solution of these equations is elaborated by implementing structured and unstructured meshes using numerical methods such as (finite volume method, and finite element method). CFD has been around since the early 20th century as a tool analyzing air flows around cars, aircraft and performing the cooling systems of data centers and electronic chips.
CFD software like Ansys, Solidworks, OpenFOAM, ADINA, etc. are playing a key role in medicine and biology, where researchers create virtual reconstructions of different human organs, surgical options, and blood flow system. It is common to combine fluid dynamics results with a simplified model of the human body such as the vascular and pulmonary systems. Simulations can help determine, with an acceptable accuracy, the distribution of blood across the arteries including possible energy losses at surgical connections.
Challenges and Outlooks
Nanotechnology has advanced in theoretical and practical research in all fields of biomedicine. Cancer treatment gained new grounds as the line between nanotechnology and immunotherapy continue to blur. Carbon nanotubes antibodies now exist that can identify and destroy tumor cells. Many experiments have been done to show the possibility of anticancer immune reaction increase of tumor cell by using CNTs as delivery Media.
The ongoing development of computer technology allows the increase the mesh resolution of numerical models used in computational fluid dynamics. Indeed the blocker that inhibits the growth of such promising technology is the technology of computers. But as long as Moore’s Law is true, we can expect more advancement in this field in the future. This is also true for mechanical engineering in biology and medicine as a whole.