Mini Bioprinter
Canadian 3D bioprinter prints patches for deep wounds on the skin
The portable device fits in your hand and weighs 997 g. He can print a skin "patch" 2 cm wide in a couple of minutes.
Photo from the press release of the University of Toronto U of T researchers develop portable 3D skin printer to repair deep wounds – VM.
Tests of the 3D bioprinter were carried out on large and small animals: for this, a 20x40 mm wound was cut out on the animal's skin, an agarose substrate was made, after which a layer of printed biomaterial was applied.
The figure above shows a diagram demonstrating the bioprinting process. The cells are suspended in a hydrogel solution. Then one (or, if necessary, several) syringes are filled with them. Another syringe contains a solution forming cross-links (shown in blue in Figure a). This solution under moderate conditions (i.e. at natural pH and body temperature) promotes the transformation of the biopolymer solution into a gel.
After installing the filled syringes in a manual bioprinter, the bio-ink is applied as a biological material or a layer of tissue to a culture cup or directly to the wound surface. For example, biochernils containing human fibroblasts can be evenly distributed into a dermal layer with a thickness of 0.1 – 0.6 mm. Biochernils containing keratinocytes can be applied in parallel strips separated by cell-free strips, which resembles a mesh epithelial skin graft.
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 uniform transverse distribution of at least two solutions into microchannel networks located in separate planes. The cartridge has outlet holes with a width of 8, 14 and 20 mm.
Preparation of the 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 being poured onto sterile Petri dishes, which leads to the formation of a 3 mm thick gel layer. The gel hardens in 30 minutes at room temperature.
Preparation of biochernils
The researchers prepared biochernils with three different compositions.
1. For alginate collagen layers: sodium alginate was dissolved in DMEM solution and 20 mmol/L of GEPES and filtered using 0.1 microns syringe microfilter. Type 1 collagen was balanced to pH 7 using 1 g/mol NaOH in phosphate-salt buffer solution (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. Biochernila for the dermal layer: 5% fibrinogen was dissolved at 37 ° C in PBS with moderate stirring for 2 hours. 1% of 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. Biochernils for the epidermal layer: prepared with a final concentration of 2.5% fibrinogen and 0.25% hyaluronic acid.
Before and after ink application (scale size – 10 mm).
The device's development team hopes that someday their device will be used in a clinical setting to improve the treatment of burns and other severe skin injuries.
The full text of the work is available at the link.
A similar device was created by Korean scientists back in 2017. It was a 3D bioprinter that printed a biomaterial that strongly resembles human skin in composition, but the cost of such material was 50 times cheaper than that of analogues. 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-pen that is able to print cartilage tissue directly on damaged areas of the body: bones, tendons or muscles. The biomaterial was created from hydrogel and stem cells. The composition was treated with ultraviolet irradiation.
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