A chitosan-integrated antibacterial protein composite nanocomplex derived from barnacle cement and spider silk

While barnacle cement protein cp19k (from Megabalanus rosa) possesses remarkable adhesion properties and spider silk protein MaSp1 (from Nephila clavata dragline silk) demonstrates exceptional toughness, their advancements in medical biomaterials are significantly hindered by their limitations in antimicrobial properties. In this study, composite nanocomplexes incorporating chitosan and proteins derived from barnacle cement and spider silk were designed and biofabricated for enhanced antibacterial properties. The impact of chitosan's molecular weight on the properties of nanocomplexes comprising cp19k-MaSp1/chitosan, MaSp1/chitosan, and cp19k/chitosan was evaluated. The results revealed that low molecular weight chitosan (LMWC, Mw = 1 kDa) forms nanocomplexes that exhibit distinct structural differences in comparison to those formed with high molecular weight chitosan (HMWC, Mw ≥ 150 kDa). Furthermore, cp19k-MaSp1/C_150k exhibited the most potent antibacterial activity against E. coli and S. aureus, surpassing the performance of cp19k, MaSp1, cp19k-MaSp1, and chitosan individually, achieving inhibition by disrupting the bacterial cell membrane structure and elevating the intracellular ROS level. Meanwhile, On day 6, the viability of HUVECs (Human Umbilical Vein Endothelial Cells) of cp19k-MaSp1/C_150k had attained a level of 145.21 ± 6.23 %, representing a substantial elevation when compared to C_150k. The remarkable biocompatibility of nanocomplexes cp19k-MaSp1/C_150k holds potential for application in wound dressings and tissue repair.