A tissue is an aggregate of cells, growing and thriving in an environment where they adhere and interact with one another. Tissue Engineering is the use of bioengineering methods to create, improve, develop and grow tissues, which then may be used for grafting, cartilage repair or, ultimately, regenerative medical procedures. The study of tissues is aimed at determining the answers to fundamental questions such as how cells react and interact in a specific matrix, and may involve the use of proteomics to study gene expression and protein production in complex environments. This form of systems biology might look at cellular functions such as excretion of intercellular signaling substances, and epigenetic factors that determine physical features such as size and shape of organs.

One of the goals of tissue engineers is to reverse the effects of injury or aging of cartilage, nerve damage or scarring from burns and other trauma. Another major achievement would be the ability to grow entire organs using stem cells taken from the organ recipient, replacing the need for a suitable donor and eliminating the risk and waiting time required for finding said donor, or the potential complications of xenotransplantation.

One breakthrough in tissue engineering announced in 2009 was the development of a biodegradable resin, by a group at University of Twente, that could be used as a scaffold in situ, for human organ generation. Another significant development, announced by scientists at Stanford and NY University School of Medicine, was the ability to grow tissues in an environment of well-vascularized cells. Using laboratory animals, they demonstrated that fatty tissue from the groin area of rats containing blood vessels, fat and skin, could be used as a scaffold for stem cells. They called the scaffolds "explanted microcirculatory beds" (EMBs). Once the cells are well embedded in the tissue they can be transplanted back into the animal, where they are not rejected. Both of these discoveries hold enormous promise for therapeutic cloning and organ transplant research.

_Sources:

InSciences Organisation. Breakthrough in Twente: Biodegradable synthetic resin replaces vital body parts. 13 June 2009.

Chang et al. 2009. Tissue engineering using autologous microcirculatory beds as vascularized bioscaffolds. FASEB Journal, March 2009. doi:10.1096/fj.08-114868.

There are many challenges to making stem cell therapies such as regenerative medicine actually work in a therapeutic setting. We might be able to harvest stem cells, from either blastocysts or by creating pluripotent cells from already differentiated tissues, but that's really only the beginning of a medically viable process. Once a cell line is cultured in a maintainable way, the following questions remain:

• How to direct differentiation into the desired tissue type
• Optimizing growth conditions and the physical environment for cell cultures or for growing organs for transplant
• How to inject and transport stem cells to the target location in the body

It's the year 1847, at a hospital in Vienna. The theory of spontaneous generation is still prevalent in medical circles and story of biotechnology has not yet begun. Hungarian doctor, Ignaz Semmelweis, noting high incidence of post-partum deaths from puerpural fever (caused by Streptococcus organisms), in a wing where medical students are trained, postulates that the students were spreading diseased particles to the new mothers after having handled infected cadavers. He begins a program wherein the students wash their hands with chlorinated water before making rounds, and the death rate drops dramatically.

Although Dr. Semmelweis was not quite on the mark about the cause of childbed fever, he had pinpointed a key fact that we take for granted today: Hand washing prevents the spread of germs. A key strategy for fighting H1N1 (Swine Flu) around the world today, is public education on the importance of washing our hands especially after sneezing, blowing noses or contact with other potentially infected individuals. Dr. Semmelweis was ridiculed by the medical profession and lost his job. Imagine where we would be today, in the fight against Swine Flu, if the germ theory had never caught on? If only he was around today to see how significant his observations were!

The Semmelweis Society International is a website named in honor of the shamed doctor, with the intent to address bioethics issues and assist physicians and other medical professionals who are falsely accused of misconduct or subjected to biased peer review.

_{Source: Biotech Chronicles: www.accessexcellence.org}

It's Veteran's Day in the USA, Remembrance Day in Canada and England, and, while it may be called something different in other countries of the world, a day to remember the sacrifices of those who defend our freedom. Did you know there's a connection between World War II and one of the greatest discoveries in biotechnology? In the late 1920's Alexander Fleming made a chance discovery, that Penicillum mold, while non-toxic to humans, secreted an antibacterial substance. In 1929, his paper on the topic did not garner much interest, but during WWII, two chemists at Oxford, Howard Florey and Ernst Chain, isolated the substance, called penicillin, and discovered it kept it's antibacterial properties when dehydrated and stored as a powder.

Development of this substance into a drug was expedited by the need for an antibiotic to treat soldiers injured in the war. Thus, penicillin saved the lives of many veterans, and, as the first antibiotic, is one of the most significant achievements in the history of biotechnology.

Scientists would later discover restriction enzymes while investigating bacterial defenses against antibiotics. Antibiotics and restriction enzymes are two very important tools that made it possible to develop techniques for cloning and studying genes.