Forefront Researches of Computational Material Science Tissue Engineering Self-Assembly Monday, 10/28/2002

Nano-indentation Snapshots illustrating the surface region during indentation. The small spheres on the diamond tip are hydrogen atoms. a) Initial configuration. (b) Indentation of 1.2 nm.

Computational Solid Mechanics Stress, strain, constitutive model Defects, dislocation Fracture Surface roughness Biomedical Engineering Information Technology Nanotechnology Bio/IT/Nano Bio/IT/Nano FEM, MPM MD, MC

Tissue Engineering Design and grow human tissues outside the body for later implantation to repair or replace diseased tissues.

Biological Hierarchy Atoms  Macromolecule  Organelle  Cell  Tissue  Organ

Simulation at Molecular Level The ability to measure, model, & manipulate at the molecular level is essential for understanding & designing biological systems.

Bone Tissue Engineering

Scaffold Guided Tissue Regeneration

Diffusion of Seed Cells Scaffolds are typically prefabricated, then seeded with cells by placing the scaffolds in liquid milieus of cells that diffuse into and attach to the scaffolds.

Vessel Grow While a vascular supply can grow into an implanted scaffold from surrounding vascularized tissue (figure to the left), this angiogenesis process takes time; cells in the interior may die before angiogenesis occurs.

Heterogeneous System Scaffold-based tissue engineering methodologies could benefit from a manufacturing process which could fabricate scaffolds that not only have controlled distributions of cells, but also spatial gradients of cells. For example, the vision of building up complete systems of seeded scaffolds, like a functioning arm with interconnected muscle, tendon, cartilage, nerve, skin, and vasculature, have been put forward.

Microstructure of Different Strength It may be desirable to have a scaffold design where one portion of the scaffold incorporates a material or microstructure optimized for strength, while another portion has another material composition or microstructure optimized for initial tissue in-growth.

Self-Assembly Process Process in which supermolucular hierarchical organization is established in a complex system of interlocking components.

Self Assembly Monolayer The substrate, Au on Si, is immersed into an ethanol solution of the desired thiol(s). Initial adsorption is fast (seconds); then an organization phase follows which should be allowed to continue for >15 h for best results. A molecule which is essentially an alkane chain, typically with10-20 methylene units, is given a head group with a strong preferential adsorption to the substrate used.

Self-Assembly Self-assembled monolayer

Simulations of SAM

Molecular Self-Assembly (MSA) Biological organisms are composed of molecular building blocks, such as nucleic acids, proteins, and phospholipids, and are equipped to assemble these components into extremely well-organized structures—themselves.

Bacteria-Phage Its structure makes sense only in the light of the specific purpose of encountering its prey and injecting the contents of its polygonal head inside.

Langmuir-Blodgett Films Langmuir-Blodgett films are built up by a process of successive deposition of individual monolayers which self-assemble on a water surface.

Self-Assembly Material A defining feature of these kinds of materials is self-assembly of building blocks in a parallel fashion into a desired structure or hierarchical construction rather than serial construction one unit at a time. The further development of the science and implementation of the technology is expected to lead to advances in electronics, photonics, composites, biomaterials, drug delivery, separation science and catalysis, to name but a few.