Alternative biomaterials: Natural, non-woven, fibroin-based silk nanofibers of weaver ants ( Oecophylla smaragdina)

Abstract

Silks of silkworms and spiders have been widely studied as biomaterials, however, none has been reported on silks produced by weaver ants ( Oecophylla smaragdina). This study is the first to report on some properties of natural silk fibers of weaver ants and their potential application as a cell matrix. Weaver ant fibrous mat contained non-woven mesh of fibers with diameters ranging from 266 to 3056 nm. The average diameter of fibers was 766 ± 326 nm. The thickness, mass, and apparent density of the fibrous mats were 39.0 ± 9.8 μm, 0.8 ± 0.1 mg/cm 2, and 0.22 ± 0.03 g/cm 3, respectively. Freshly made fibrous mats by weaver ants were highly hydrophilic as determined by water contact angle analysis, whereas older ones were quite hydrophobic. TG–DTA analysis revealed a major weight loss peak from 260 up to about 330 °C, similar to the decomposition peak of Bombyx mori fibroin. FT-IR spectrum showed amide I, amide II, amide III, C–H and C–O peaks, which were attributed to random coil and β-sheet conformation in the protein structure of the weaver ant fibers. The fibrous mat was slight toxic to the fibroblast NIH 3T3 cells (37.8% cell death), probably due to some toxic particles deposited on the fibers. Nevertheless, weaver ant fibrous mat served as a good matrix for cell adhesion. Results of this work provided evidence for the properties and a potential application of natural weaver ant fibers as an alternative, natural, fibroin-based matrix.