Canadian 3D bio-printer prints skin patches for deep wounds

Portable bioprinter weighs only 997 grams.

Researchers at the University of Toronto have developed a 3D bio-printer capable of printing strips of biomaterial for healing deep wounds on the skin. The portable device fits in your hand and weighs 997 grams. He can print a skin patch of 2 cm wide in a couple of minutes.

Tests of a 3D-bio-printer were carried out on large and small animals: for this, a wound of 20x40 mm in size was cut out on the animal's skin, a substrate was made of agarose, after which a layer of printed biomaterial was applied.

Materials and methods



The figure above shows a diagram demonstrating the bioprinting process. Cells are suspended in a hydrogel solution. Then they fill one (or, if necessary, several) syringes. In another syringe contains a solution that forms cross-links (in figure a is shown in blue). This solution in moderate conditions (ie, at natural pH and body temperature) contributes to the transformation of the biopolymer solution into a gel.

After installing the refilled syringes in a bio-manual bioprinter, they are applied as a biological material or a layer of tissue onto a culture dish or directly onto the wound surface. For example, bio-ink containing human fibroblast can be evenly distributed in the dermal layer with a thickness of 0.1 - 0.6 mm. Biointerns containing keratinocytes can be applied in parallel strips separated by cell-free strips, which resembles reticular epithelial skin grafts.

Microfluidic cartridge

The main part of the instrument is a microfluidic cartridge made of translucent polymer. It was created on a 3D printer. The cartridge provides a uniform transverse distribution of at least two solutions in microchannel networks located in separate planes. The cartridge has 8, 14, and 20 mm outlet openings.

Preparation of agarose substrate

A solution of 2% agarose in deionized water is prepared by heating with microwave radiation. The solution is cooled to 60 ° C before pouring it onto sterile petri dishes, which leads to the formation of a gel layer 3 mm thick. The gel hardens after 30 minutes at room temperature.

Preparation of bio-ink

Researchers prepared bio-ink with three different formulations.

1. For alginate collagen layers: sodium alginate was dissolved in a DMEM solution and 20 mmol / l HEPES and filtered using a 0.1 μm syringe microfilter. Type 1 collagen was balanced to pH 7 with 1 g / mol NaOH in phosphate-buffered saline (PBS). The two initial solutions were mixed to result in a concentration of 5 mg / ml of type 1 collagen and 2% alginate. The solution was kept on ice before use.

2. Bioavailability for the dermal layer: 5% fibrinogen was dissolved at 37 ° C in PBS with moderate agitation for 2 hours. 1% hyaluronic acid was dissolved in PBS. The solutions were mixed in a ratio of 1: 1, and then filtered. The type 1 collagen solution was balanced with NaOH to pH 7 and mixed with a filtered fibrin / hyaluronic acid solution to result in a concentration of 1.25% fibrinogen, 0.25% hyaluronic acid, and 0.25% collagen. The solution was kept on ice before use.

3. Bio-ink for the epidermal layer: prepared with a total concentration of 2.5% fibrinogen and 0.25% hyaluronic acid.


Before and after applying ink (Figure f)

The device development team hopes that someday their device will be used in a clinical setting to improve the treatment of burns and other severe skin damage.
The full text of the work is available here .

A similar device was created by Korean scientists back in 2017. It was a 3D bio -printer that printed a biomaterial strongly resembling human skin, but the cost of such a material was 50 times cheaper than its counterparts. The skin was created on the basis of collagen material and polyprolactone and matured for two weeks.

And scientists from Australia have created a 3D-printed bio-organ that is capable of printing cartilage tissues directly on the damaged areas of the body: bones, tendons or muscles. The biomaterial was created from hydrogel and stem cells. The composition was treated with ultraviolet radiation.

More on future medicine and 3D printing - at robo-hunter.com.