Bioengineering

Biomaterials are materials designed to interact well with biological organisms or molecules. They may come from an organism, be produced by an organism, or be made as a synthetic polymer. Because of these properties, engineers use biomaterials in medicine and other biological applications.

These materials are used in tissue engineering, biosensing, and drug delivery. Tissue engineering uses materials to support the growth or repair of tissues. Biosensing uses materials to detect biological...

Collagen is a useful biomaterial with uses that go beyond the lab. It has also found commercial use in photography. In tissue engineering, collagen can be turned into hydrogels that give engineered tissue support and structure.

This page follows the path from porcine skin to a collagen hydrogel. Porcine skin is used as the source of collagen. The material is then prepared for use in tissue engineering applications.

The video also shows several applications of collagen and the methods used to...

Silk cocoons can be processed into a soluble material that is useful for making biomaterials. Silk fibers have been used for fabrics and threads for centuries, but turning them into a versatile pre-polymer solution is a newer technique. That solution can then be shaped into materials with controllable mechanical properties.

The process begins with silk worm cocoons. The silk is solubilized, or dissolved, so it can be handled as a liquid-like solution. The video then shows how that silk...

Bio-microelectromechanical systems, or BioMEMs, are microscale devices used in diagnostic settings. They work with very small sample and reagent volumes in vivo and in vitro, which means inside a living body or outside it in a lab. These compact systems support bioengineering research and help make diagnostic tools more efficient.

BioMEMs can carry out functions such as filtration, sensing, and synthesis on a tiny scale. Using less material can lower costs and improve sensitivity. The...

Photolithography is a common microfabrication method used to pattern a silicon wafer. It uses light to transfer a design onto the wafer surface. This process helps form the basis for many BioMEM devices.

The page also shows how photolithography is carried out in a cleanroom. Cleanroom steps are important because they support careful fabrication of small, detailed features. The video ends by introducing applications of this process in BioMEM device production.

Photolithography and soft lithography are used to make BioMEM devices such as microfluidic channels. A microscale pattern is copied by curing an elastomeric polymer over a 3D structure. The result is a polymer piece that can serve as part of a biological device.

These polymer structures are then used to build a range of tools. Some are microfluidic channels for biosensing applications. Others are microscale bioreactors that let scientists visualize micro-colonies.

The process also shows how...

Bioprocessing uses living organisms to make a desired target product. In many cases, that product is a protein made in a bioreactor, which is a controlled vessel for growing cells.

This process often relies on genetically engineered organisms. Engineers design the system so the cells can produce proteins at large scale. That approach is central to making biotherapeutics, which are drugs made from biological materials.

Biotherapeutics are important medicines for complex diseases such as...

Synthetic biology is a bioengineering method for programming cells to make useful products. In many cases, the goal is to genetically modify an organism so it can produce large amounts of a protein. That protein may already be made by the cell, or it may come from a newly inserted DNA sequence.

The process depends on changing an organism’s genetic material. This is done with transformation or transfection, two common ways to introduce DNA into cells. The video also shows how this work is...

Bioreactors are used to grow organisms in large volumes. This makes it possible to produce large amounts of a target product. In laboratory and bioengineering settings, they provide a controlled place for cell growth and product formation.

The two main reactor types are batch reactors and continuous reactors. A batch reactor contains all of the materials needed for cell growth at the start. A continuous reactor has inlet and outlet ports, so fresh growth media can be added while cell waste is...

Biosensors detect biological molecules and chemical contaminants by combining biology with physical measurement. They can identify targets such as proteins or cells, as well as non-biological molecules like chemicals or contaminants. This makes biosensing a useful field for studying and monitoring many kinds of samples.

These devices rely on different signal types to find the target molecule. Some biosensors use electrical signals, while others depend on optical, electrochemical, or mechanical...

Electrochemical biosensors detect target molecules by measuring an oxidation-reduction event. That signal changes when a molecule binds to the sensor surface. These sensors helped shape modern biosensing after the first glucose biosensor was invented.

The glucose biosensor is a key example of this technology. It shows how electrochemical sensing can track a biological target through a measurable electrical change. The same basic idea also helps explain how electrochemical biosensors can be...

Optical biosensors detect target molecules with light. They monitor binding by reading an optical signal from the sample. This makes them useful for seeing when a target molecule is present.

Some optical biosensors use a label molecule. The label creates a measurable signal, such as fluorescence. Other optical biosensors are label-free and track changes in optical properties, such as refractive index, as binding occurs.

This page introduces both label and label-free optical biosensors. It...

Tissue engineering uses biomaterials, specific cells, and growth factors to build artificial tissue. These engineered tissue constructs are designed for tissue repair and, in some cases, organ replacement.

The field focuses on how to make tissue work like natural tissue. It begins with a scaffold, which is a structure that supports cell growth. Cells are then added to the scaffold, and growth factors help encourage proliferation, or cell multiplication.

The video also outlines common methods...

Histotypic tissue culture uses an engineered three-dimensional matrix to grow and propagate cells. Compared with common two-dimensional tissue culture, cells in a 3D setting behave more realistically and better mimic native tissue. The method is useful when high cell density is needed.

The process begins by harvesting cells from donor tissue. Those cells are then placed onto an engineered construct for culture. This setup supports growth in a three-dimensional space instead of a flat surface.

Whole organs can be cultured ex vivo using specialized bioreactors to support repair or replacement of entire organs. In this approach, a donor organ is first stripped of all cells. What remains is the three-dimensional structure of the organ, which can then be repopulated with new cells.

The lung is the example shown here. The method uses a dynamic culture system that provides mechanical stimulation, similar to what the organ experiences in the body. This type of culture helps induce native...