Translated material
Cell constructor
A new technology for growing internal organs has been developed
Tissue engineering is one of the most promising areas in the creation of artificial tissues and organs. The main obstacle to growing substitutes in the laboratory is that cells tend to create flat structures, while doctors want three-dimensional ones. Scientists at the Harvard Institute for Health Sciences and Technology (HST) have figured out how to control this process.They have developed a technology that is very simple and resembles the process of building toy houses from children's construction blocks. The role of concrete or mortar, which binds the cellular bricks during hardening, is played by a gel-like material.
The author of the technology for creating three-dimensional cellular structures, already called “microcladding,” is Professor Ali Khademhosseini, who described the technology and the results of his experiments in the online journal Advanced Materials. Khademhosseini's tiny cell bricks have great potential for creating artificial tissues and organs. In the first step, HST scientists needed to obtain individual cells. They divided biological tissue into individual cells using special enzymes. The released cells, however, are extremely difficult to collect together and give them the shape of natural tissues and organs.
Previously, some researchers were quite successful in creating simple tissues and organs, such as skin, cartilage or the bladder, using special scaffolds made of soluble biomaterial. This technology is quite reliable, but, unfortunately, it is only applicable for growing simple tissues and organs.
Harvard scientists used the polymer polyethylene glycol (PEG) as a cell-binding solution in their biological construct, which, depending on the average molecular weight, can be either a viscous liquid or a solid. It is used in rocket fuel, solvents, medicine and cosmetics as a base for ointments. Ali Khademhosseini used in his technology a polymer in liquid form, which turns into a gel under the influence of ordinary light. When PEG-coated cells are exposed to light, the polymer hardens into cell cubes with an edge length of 100 to 500 micrometers, i.e. millionths of a meter.
Next, spatial structures of the required shape are created from the cell cubes obtained using the polymer. In this case, templates are made of polydimethylsiloxane (PDMS), a linear silicon-based polymer, which is widely used in many fields of science and technology, incl. in medicine. Both cell cubes and PDMS are again coated with polyethylene glycol. It acts as an adhesive and holds the cubes together as they tightly fill the PDMS frame.
After the cell cubes take the required shape, they are again exposed to light. The PEG connecting the cubes turns into a gel. After removing the template, the cellular structure retains the desired shape.
Ali Khademhosseini and his colleagues have already created cell tubes using their technology that can act as capillaries. This will help solve one of the most serious problems with engineered organs - their blood supply. Otherwise, the organs die.
Scientists, even before Khademhosseini's research, had learned to produce complex three-dimensional tissues. However, this technology, called organ printing, is complex and impossible without a special device - a bioprinter. Khademhosseini's technology does not require any special equipment, is simple, and can be used in any laboratory.
It is still unclear when it will be possible to create organs from artificial tissues obtained using microlaying that can replace donor organs. Now Ali Khademhosseini and his assistants are testing its effectiveness for different types of cells. In addition, scientists are looking for polymers that can replace polyethylene glycol and allow better control of cell structuring.