Development of Salmon Sperm DNA/Regenerated Silk Bio-Based Films for Biomedical Studies on Human Keratinocyte HaCaT Cells under Solar Spectrum

Abstract

In this study, we fabricated adhesive patches from silkworm-regenerated silk and DNA to safeguard human skin from the sun’s rays. The patches are realized by exploiting the dissolution of silk fibers (e.g., silk fibroin (SF)) and salmon sperm DNA in formic acid and CaCl2 solutions. Infrared spectroscopy is used to investigate the conformational transition of SF when combined with DNA; the results indicated that the addition of DNA provides an increase in the SF crystallinity. UV–Visible absorption and circular dichroism spectroscopy showed strong absorption in the UV region and the presence of B-form of DNA once dispersed in the SF matrix, respectively. Water absorption measurements as well as thermal dependence of water sorption and thermal analysis, suggested the stability of the fabricated patches. Biological results on cellular viability (MTT assay) of keratinocyte HaCaT cells after exposures to the solar spectrum showed that both SF and SF/DNA patches are photo-protective by increasing the cellular viability of keratinocytes after UV component exposure. Overall, these SF/DNA patches promise applications in wound dressing for practical biomedical purposes.

Electrospun Nanofibrous UV Filters with Bidirectional Actuation Properties Based on Salmon Sperm DNA/Silk Fibroin for Biomedical Applications

“…This indeed suggests that the main structure of the employed DNA solutions is the B-form. We observed that the DNA retains this structure also when inserted in the SF matrix, as reported in a previous work . Moreover, UV–vis spectra of the initial SF/DNA solutions and films were measured and compared, as shown in Figure c.…”

“…We observed that the DNA retains this structure also when inserted in the SF matrix, as reported in a previous work. 35 Moreover, UV−vis spectra of the initial SF/DNA solutions and films were measured and compared, as shown in Figure 1c. The absorption spectrum of SF film appears to be very similar to that of the native solution.…”

“…HaCat cells were seeded in 35 mm dishes, at different concentrations: 1 × 10 4 cells/cm 2 , 5 × 10 3 cells/dish, 2.5 × 10 3 cells/dish and after 4, 24, and 48 h, respectively, of incubation after 220 s of irradiation. Cell viability was calculated as previously described in ref ( 35 ).…”

“…In this framework, deoxyribonucleic acid (DNA) and silk fibroin (SF) are inexhaustible natural polymers that can be extracted from living organisms. , DNA is water-soluble and has UV-absorption ability, while SF can form crystalline domains with a β-sheet conformation. Taking advantage of these intrinsic properties of SF and DNA, in a recent study, we reported the fabrication of adhesive films with UV-blocking properties, starting from the dissolution of silk fibers and salmon sperm DNA in calcium chloride (CaCl 2 )/formic acid solution. However, it is known that the mechanical properties of silk are due to its hierarchical fibrillar structure. , A more sustainable approach to preserve the fibrillar structure can be achieved using a conventional dissolving system.…”

“… 33 , 34 DNA is water-soluble and has UV-absorption ability, while SF can form crystalline domains with a β-sheet conformation. Taking advantage of these intrinsic properties of SF and DNA, in a recent study, 35 we reported the fabrication of adhesive films with UV-blocking properties, starting from the dissolution of silk fibers and salmon sperm DNA in calcium chloride (CaCl 2 )/formic acid solution. However, it is known that the mechanical properties of silk are due to its hierarchical fibrillar structure.…”