As a common three-dimensional (3D) printing technique, extrusion free-forming, also known as robotic dispensing or microsyringe
deposition, has the potential for the skin tissue engineering owing to its numerous advantages, such as wide-range printing materials and moderate work environment.
The experimental system included two microsyringe
pumps in which 10g of air-dried feed and solvent are pushed out with a constant flow rate.
Then, we used a 5 [micro]L flat-headed microsyringe
(Hamilton 600, Switzerland) to infuse 0.5 U type IV collagenase (Sigma-Aldrich, USA) which was dissolved in 2.5 [micro]L saline solution.
Droplets of the colloidal solution (~0.2 [micro]L) were deposited with a microsyringe
(total volume: 1 [micro]L) on the substrate, which was cleaned thoroughly by alcohol and distilled water and dried in a drying oven.
with 5 [micro]L of [[C.sub.4]mim][P[F.sub.6]] was positioned above the vial, and the needle was inserted through the septum.
The virus was infused using a 10[micro]l nanofil syringe and 34-gauge needle (World Precision Instruments) mounted to a stereotaxic automated injector (Micro4 MicroSyringe
Injector; World Precision Instruments) at a rate of 0.05ml/min.
A single dose of filtered air (20 [micro]L) or [O.sub.3] (10, 20, or 30 [micro]g/mL [O.sub.3], 20 [micro]L) was administered over a period of 20 s by the microsyringe
. [O.sub.3] mixture was created by a medical ozone generator (CHY-31, Yuehua Company, China).
While maintaining a fixed volume (2 [micro]L) of the test solution, increasing volumes of the reference standard, ranging from 1.0 to 2.4 [micro]L of the 1 mg/mL solutions, were spotted onto the plate using a Hamilton microsyringe
. Thus, the volume in [micro]L corresponded to the weight of substance in [micro]g.
After SCI, 10 [micro]L (containing 3 [micro]g/[micro]L bFGF wherever applicable) of HP, HP-bFGF, HP-DPSC, and HP-bFGF-DPSC hydrogels was in situ injected by a microsyringe
. Animals in SCI model group received the same surgical procedures and were injected with sterile saline solutions (10 [micro]L per animal).
Ltd., Schweiz) was injected into the vitreous body with a microsyringe
(YuanQuan Biological Technology Co.
Rats were anesthetized with 2.5 [+ or -] 0.2% isoflurane vaporized into a mixture of 30% O[sub]2 and 70% N[sub]2, through a gas anesthesia mask (Model 929-B Rat Gas Anesthesia Head Holder; David Kopf Instruments, Tujunga, CA, USA), and delivered at a flow rate of 5 L/min.[sup] Rats were fixed in a stereotaxic apparatus, and holes were drilled (0.8 mm posterior to the anterior fontanelle, 1.5 mm right lateral to the anterior fontanelle) based on a stereotaxic rat brain atlas.[sup] A microsyringe
was placed in the hole toward the right ventricle until the needle had penetrated and was withdrawn with cerebrospinal fluid.
Drugs were injected slowly with a Hamilton microsyringe
into one of the LV under stereotactic guidance (Brega: 1.2 [+ or -] 0.4 mm, deep: 3.2 [+ or -] 0.4 mm, right to median sagittal plane: 1.4 [+ or -] 0.2 mm) over 15 min.