Vicryl rapid

Loop brushes were designed for operation with a 22G FNA needles and comprise a 1 cm long wire loop attached to a 99 µm nitinol guidewire (Niti#1, straight annealed light oxide, Fort Wayne Metals). The loops are made from one of seven commercially available 6/0 absorbable suture wires: Chirlac (Vitrex, PG0201), Chirasorb (Vitrex, LV0201), Monocryl (Ethicon, W3215), PDS II (Ethicon, Z489E), Vicryl Rapid (Ethicon, W9913), Glycolon (Resorba, PB41504) and Catgut Chrom (SMI, 2,101,512), all obtained from SuturerOnline.se (Malmö, Sweden) (Fig. 2a–h). Given the unique packaging of Catgut in hydrating fluid (isopropanol and water), these sutures were air-dried for 24 h before assembly. Control loop brushes were created using 50 µm diameter nitinol wire (Niti#1, straight annealed light oxide, Fort Wayne Metals) (Marques et al. 2021 (link)). Loop brushes were assembled by manually placing wire loop ends adjacent to the guidewire and fixating the parts with 1 µL of 4011 Loctite glue dispensed via a pipette. The loop brushes were then inserted into the lumen of 22G hypodermic needles (4710007040, Henke-Sass Wolf, Germany).Fig. 2

Photographs of loop brushes of different loop materials inserted in 22G needles: a Chirlac; b Chirasorb; c PDS II d Monocryl e Vicryl Rapid; f Glycolon g Catgut, and; h Nitinol

Anesthesia and surgery were performed as described previously^{12 (link)}. In brief, after preoperative analgesia (buprenorphine 0.03 mg/kg, s.c. and carprofen 5 mg/kg, s.c.), the rat was anesthetized with isoflurane and the right tibia aseptically prepared. A 1 cm incision was made on the proximolateral aspect of the right tibia. A ø1.2 mm unicortical hole was drilled 2 mm distal to the growth plate, then tapped (2 mm outer ø/1.2 mm inner). After the sterile or colonized screw was inserted manually, the fascia and skin were closed in two layers using absorbable suture material (Monocryl and Vicryl rapid, Ethicon Inc., Cincinnati, USA; sizes 6–0 and 5–0, respectively). For postoperative analgesia, buprenorphine (0.05 mg/kg, s.c.) was administered every 12 h for 3 days and paracetamol (7 ml Dafalgan syrup/100 ml water; Bristol-Myers Squibb) was given via drinking water for a period of 7 days.

The animals were put under general anesthesia induced by intraperitoneal injection of a mixture of Ketamine (50 mg/ml) and Medetomidine (1 mg/ml) in a 1:1 ratio. Each animal received 0.04 ml anesthetic solution per 20 g body weight. One 3D bioprinted construct was surgically implanted in a subcutaneous pocket on the back of each mouse (Fig. 1). All constructs were identical in composition. The skin pockets were then closed with Vicryl Rapid (Ethicon, Sommerville, N.J.).
Each animal carried the 3D bioprinted constructs for 45 days and were then, once again, put under general anesthesia. The back-skin pockets were opened and a 10 × 10 mm full-thickness skin graft from the donor mouse was transplanted on to the 3D printed constructs and fixated with Prolene 8-0 sutures. The pocket was again closed with Vicryl, and sealed with wound tape. After 60 days, half of the mice were randomly chosen and euthanized, and the constructs were explanted. The other group was instead put under general anesthesia a third time. The pocket roof was removed, and the surrounding skin was sutured edge-to-edge to the transplanted skin covering the 3D printed construct. The area was then covered with wound tape.
After 75 days, the constructs were harvested and fixated in 4% buffered formaldehyde supplemented with 20 mM CaCl₂ overnight at 4°C and embedded in paraffin (Table 1).