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Viscoelasticity basic The time-dependent material behavior is called viscoelasticity Viscoelasticity = Viscosity + Elasticity Viscosity is a fluid property and is a measure of resistance to flow Elasticity is a solid material property relationship between stress and strain Stress is a function of strain and strain rate Time-dependent material properties 图 The short-term behavior is relatively unchanged over a wide time scale, and this is termed the glassy plateau Similarly, if the mat ...

Tendons and Ligaments Function of T&L Although tendons and ligaments are mechanically passive (i.e., they do not contract and produce motion as do the muscles), each plays an essential role in joint motion and stability. tendons 肌腱 attach muscle and transmit the tensile load generated through muscular contraction or passive elongation to bone produce joint motion or promote joint stability contribute to maintaining body posture. tendons and muscles compose the muscle tendon unit acts as ...

组织工程基础 Key elements of Tissue engineering cells sacffolds signals goal Tissue Engineering is the in vitro development (growth) of tissues or organs to replace or support the function of defective or injured body parts, or the directed management of the repair of tissues within the body (in vivo) 组织工程是在体外培养(生长)组织或器官，以替代或支持受损或受伤身体部位的功能，或对体内组织(体内)进行有目的地修复管理 Tissue engineering aims at repairing damaged tissue that is insufficient or cannot be repaired by the intrinsic repair mechanisms of organs ...

Cells basic Cells are the basic building blocks of living organisms, around 20 micrometer in diameter they can survive in isolation only under carefully controlled conditions Most cells will not grow well in suspension, and so they are usually grown attached to a substrate 组成 细胞核,细胞质,细胞器,细胞膜 All eukaryotic cells contain a nucleus, in which is located the genetic material that ultimately controls everything the cell is composed of and all the activities it carries out. Nucleus is surrounded by ...

basic Cell-ECM interactions Dynamic reciprocity 动态互作 the mechanism of ECM is an important component in embryonic inductions 动态互作解释了ECM在胚胎诱导过程中的机制 整体就是ECM与细胞表面受体分子作用, 受体分子调控细胞表达蛋白反过来影响ECM ECM molecules interact with receptors on the surface of cells Receptors transmit signals across the cell membrane to molecules in the cytoplasm细胞质. These signals initiate a cascade级联 of events through the cytoskeleton into the nucleus, resulting in the expression of specific genes Products of these genes, in t ...

basic Morphogenesis is the developmental cascade of pattern formation, the establishment of the body plan and architecture of mirror-image bilateral symmetry of anatomical structures, culminating in the adult form. 形态发生是模式形成的发育级联过程，涉及身体蓝图的建立、解剖结构镜像双侧对称性的构建，最终形成成体形态 The goal of tissue engineering is to locally recapitulate the developmental process of morphogenesis. 组织工程的目标是在局部重现形态发生的发育过程 The three key ingredients for morphogenesis inductive morphogenetic signal 诱导性形态发生信号 responding stem ce ...

basic Mechanisms by which cells convert a mechanical stimulus into a chemical signal Cells possess many mechanosensitive entities机械敏感实体 on their surface such as Mechanosensitive ion channels 机械敏感离子通道 G-protein coupled or grow factor receptor G蛋白偶联或生长因子受体 Extracellular matrix binding receptors 细胞外基质结合受体 Cell-cell binding molecules 细胞间结合分子 Cryptic Binding Sites 隐蔽结合位点 图 Mechanosensitive Ion Channels divided into two categories by the force vector the channels respond 根据其响应的力向量分为两类 force p ...

What to control in delivery Relevant (What?) Temporal (when?) Spatial (Where?) Nanoscale (How?) Multi-dimensional? (all above) 递送后脱落 Growth factor delivery basic Growth factors are by far the drugs of highest interest in tissue engineering. Many of the growth factors are dimers, typically a receptor (kinase) that is bound to one subunit of the growth factor phosphorylating the receptor that is bound to the other 许多生长因子为二聚体，通常是一个亚基结合激酶，使另一个亚基结合的受体发生磷酸化 Examples of growth factors BMPs, (INFUSE ...

Classification of artificial organs Bone/dental/joint replacements (limb, knee, hip, dental implants, etc.) Soft/connective tissues (skins, cartilage, ligaments, tendons, muscles, blood vessels, etc.) Sensory organs/tissues (nerves, eyes, ears, etc.) Internal organs (heart, kidney, lungs, etc.) Clinical application joint cartilage degeneration关节软骨退变, osteoarthritis骨关节炎 (OA) Primary Problem Damaged cartilage leads to various forms of arthritis 关节炎 Osteoarthrites骨关节炎 20.7 million Americans 美国有2 ...

4.Amino Acids Structure Central to this structure is the tetrahedral 四面体 alpha carbon (Cα) Cα covalently bonded to the amino group the carboxyl group a hydrogen a variable side chain R In neutral solution (pH 7), the carboxyl group exists as –COO- and the amino group as –NH3+. Peptide Bonds The amino and carboxyl groups of amino acids can react in a head-to-tail fashion, eliminating a water molecule and forming a covalent amide酰胺 linkage, a peptide bond The equilibrium for this reaction ...