Wet Electrospinning - Spingenix

Wet Electrospinning

SpingenixElectrospinningWet Electrospinning

Wet electrospinning. In wet electrospinning or wet-dry jet electrospinning, which is one of liquid electrospinning processes, a liquid collecting medium is used instead of the conductive bed collector used in conventional electrospinning. Briefly, wet electrospinning is the collection of spun fibers from a polymer solution under high electrical potential in a coagulation bath containing a low surface tension solvent that does not dissolve the desired polymer (allowing the fibers to coagulate) (Fig. 2.2).

Wet electrospinning

Since the fibers solidify faster in a liquid with low surface tension in this process, the thickness of the structures obtained is much greater than that of two-dimensional membranes. Therefore, it was observed that three-dimensional structures in the form of a sponge have lower density and more porosity than two-dimensional structures.

Due to their low surface tension compared to pure water, alcohols such as methanol (MeOH), tert-butanol (t-BuOH), ethanol (EtOH) are preferred as collection media to obtain 3D fiber structures in wet electrospinning. Polymer aggregates collected in the coagulation bath, also known as solvent-free collection medium.

uniform nanoparticle coating of cellulose fibers during wet electrospinning

Nanofibers are extracted from the bath. If the alcohol contained therein has a low freezing temperature, such as EtOH and MeOH, it is removed from the structure with distilled water, then freezing occurs at a low temperature (e.g. -80 °C). The liquid phase between the fibers is then sublimated using a freeze dryer, resulting in low-density, high-volume structures.

dry electrospinning vs wet electrospinning

Structures are preserved. The only disadvantage of the discussed method is the need for an additional drying step after manufacture.
wet electrospinning method.In the study by Viswanathan et al. [56], which first used the idea of collecting fibers in a coagulation bath, prepared a solution of cellulose and heparin in a room temperature ionic liquid (RTIL). . ), which can dissolve polar and non-polar compounds and EtOH.

By ensuring complete dissolution of the RTIL in a coagulation bath containing blood, fibrous structures of a mixture of cellulose and heparin, which retard coagulation upon contact with blood, were branched, similar to a vascular network, but not in three dimensions.

The production of 3D scaffolds was first demonstrated in the coagulation bath by Kay et al. The porosity of the 3D structures (94%) created in the MeOH-containing coagulation bath to increase the crystallinity of the SF fibers was higher than that of the freeze-dried SF sponge (90%) and the 2D membranes (84%) . Mouse 3T3.
SEM images taken of the sample surfaces after 1 week of culture with fibroblasts showed that the cells could easily invade between the 3D-SF fibers. In another study by the same group, sodium chloride with dimensions between 300 and 500 μm was used in 3D SF scaffolds.
The pore diameter was increased by adding a porosity agent. The metabolic activity of MC3T3 preosteoblast cells seeded on 3D-SF was increased by about 7-fold compared to 2D-SF scaffolds and about 4-fold compared to TCPS at day 7.

All studies on 3D wet electrospinning in the literature. Table 2.1;
It is given in Table 2.2 and Table 2.3. in the relevant tables; Polymer used, bath contents/dimensions and, if applicable, scaffold thickness, maximum pore diameter and porosity values, cell/defect model used, penetration values and target studies are specified.

An auxiliary electrode for guiding the electrospinning jet into the bath was only used in the literature by Kawahara et al [73]. A ring of stainless steel wire attached to the walls of a glass petri dish and used as a clotting bath. They used fibers to collect them in the middle of the bathroom. The ring electrode increased the electric field intensity and provided fibrous structures to target the coagulation bath. However, the SF fiber structures collected in a short rotation distance (5 cm) and a shallow bath were intensified by the influence of the electric field and their pore diameter was 10.

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