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Skin is the largest organ in the human body. It not only bears physical protection functions, but also plays a key role in immune defense, temperature regulation, and sensory conduction. Its unique structure and physiological characteristics make skin damage repair a difficult problem in biomedical research. Especially in terms of wound repair and regeneration, how to simulate the natural healing mechanism of the skin and build a microenvironment suitable for cell growth and tissue regeneration has become a hot issue in tissue engineering. At present, there are many skin substitutes and dressings used in clinical treatment, but there are still limitations in dealing with complex wounds, such as difficulty in effectively managing wound exudate, which may lead to wound deterioration and complications. Therefore, it is of great significance to develop high-performance skin scaffold materials with good exudate management capabilities.
Recently, Professors Chen Su and Chen Yong from Nanjing Tech University and Researcher Pang Jie from Fujian Agriculture and Forestry University published a research result entitled "Robust dual equivariant gradient antibacterial wound dressing-loaded artificial skin with nano-chitin particles via an electrospinning-reactive strategy" in Advanced Fiber Materials. They used microfluidic electrospinning technology to construct a three-dimensional bionic nanofiber skin scaffold, which provides a new perspective for the targeted method of accelerating wound healing. This work innovatively designed a superhydrophobic-hydrophobic-hydrophilic dual gradient three-dimensional bionic nanofiber skin scaffold (3D BNSF), with an inner layer of TPU-HGC superhydrophobic layer (water absorption), a middle layer of hydrophobic PCL layer, and an outer layer of hydrophilic PCL-PCE layer (water transmission). Due to the unique equivariant dual gradient structure, the 3D BNSF has the function of absorbing exudate-transmission, thereby effectively managing wounds. In vitro and in vivo experiments have shown that this skin scaffold has excellent antibacterial properties and cell compatibility, and can accelerate wound healing and tissue regeneration. This study provides a new perspective on targeted approaches to accelerate wound healing and opens up new avenues for the construction of high-performance artificial skin scaffold materials.
The main point of this paper
This study integrates superhydrophobic, hydrophobic and hydrophilic nanofiber membranes into a new type of isotropic dual gradient nanofiber scaffold (3D BNSF) (Figure 1), which can absorb exudate and transmit, effectively manage wounds and accelerate wound healing.
Figure 2 shows the structure and properties of superhydrophobic HGC particles, where: Figure (a) shows that HGC particles were successfully synthesized; Figure (b) shows that the particle size distribution is between 500~1000 nm, concentrated in the range of 600~800 nm; Figures (c, d) show that the HGC particles are tightly arranged by nanofibers to form a complex network, which not only gives the particles unique mechanical properties, but also improves the surface roughness; Figures (e-f) further prove that the polymer PCE was successfully prepared.
Figure 3 shows the structure and properties of 3D BNSF. PCL-PCE, PCL and TPU-HGC nanofibers prepared by microfluidic electrospinning technology not only show good scalability, but also maintain structural integrity. The contact angles of TPU-HGC, PCL and PCL-PCE nanofiber layers are 151.59°, 95.21° and 41.02°, respectively, indicating that the superhydrophobic to hydrophilic isotropic dual gradient interface was successfully constructed, which is crucial for maintaining the efficiency of biofluid transmission in BNSF and the low-humidity environment of the wound surface. The superhydrophobicity of TPU-HGC is attributed to the composite effect of HGC and TPU, and the water contact angle is increased from the original 131.58° to 151.59°.
Figure 4 is a schematic diagram of the unidirectional water transmission performance of 3D BNSF from the superhydrophobic layer TPU-HGC to the hydrophilic layer PCL-PCE. The flow of the exudate was simulated by continuous dripping of the syringe, and the bidirectional breakthrough pressure of the 3D BNSF was tested (forward from outside to inside and reverse from inside to outside). The results show that as the material gradually changes from superhydrophobic to hydrophobic to hydrophilic, the breakthrough pressure of TPU-HGC, PCL and PCL-PCE decreases significantly, from more than 70 mm H2O to less than 10 mm H2O (Figure 4b), which is attributed to the decreasing effect of surface energy; it is worth noting that the breakthrough pressure in the inward direction decreases significantly, about 32% of the reverse breakthrough pressure, and stabilizes at a level of about 22 mm H2O, indicating that it has excellent unidirectional flow conduction characteristics. When the hydrostatic pressure drops below 7 mm H2O, the hydrophobic TPU-HGC can effectively prevent the reverse penetration of water molecules, thereby protecting the surrounding tissue from dehydration.
Figure 5 shows the biocompatibility and antibacterial properties of 3D BNSF. It can be seen that the cell survival rates of all materials remain at a high level, among which the cell survival rates of the PCL-PCE, PCL and TPU-HGC groups are close to 90%, showing the advantage of 3D BNSF cell survival rate; in addition, the live/dead staining results show that the number of live cells increases with the extension of culture time, further indicating excellent biocompatibility and excellent antibacterial properties.
Figure 6 shows the wound repair process. Two types of scaffolds were used: 3D BNSF and nanofibers prepared by microfluidic electrospinning (PCL, PCL-PCE, TPU-HGC). The results showed that compared with other scaffolds, the wound area treated with 3D BNSF was significantly reduced on the 7th day, showing the potential to accelerate wound closure and tissue regeneration.
In summary, 3D BNSF has isotropic dual gradient characteristics, excellent mechanical elasticity, unidirectional fluid transmission ability, excellent antibacterial properties and good biocompatibility. 3D BNSF quickly absorbs and transfers moisture in a short period of time, keeps skin wounds dry and accelerates wound repair; at the same time, it promotes granulation tissue formation and collagen deposition, further promoting wound healing. The research results show that electrospinning technology provides an effective means for the preparation of high-performance fiber scaffold materials, and isovariant dual-gradient 3D BNSF provides a new perspective for the design of high-performance artificial skin scaffolds, which is of great significance for accelerating wound repair.
Electrospinning Nanofibers Article Source:
https://link.springer.com/article/10.1007/s42765-024-00476-8
