Avicenna Research Institute

Aim: Here, an innovative kind of antibacterial nanocomposite film is developed by incorporating graphene oxide and zinc oxide into chitosan matrix. Materials & methods: Our dressing was fabricated using the solution casting method. Fourier transform infrared spectra and TGA-DTG clearly confirmed the structure of film dressing. Results & conclusion: Our results showed the tensile strength and elongation at the break of the films were 20.1 ± 0.7 MPa and 36 ± 10%, respectively. Our fabricated film could absorb at least three-times the fluid of its dry weight while being biocompatible, antibacterial, non-irritant and non-allergic. In addition, it accelerated the healing process of infected wounds by regulating epithelium thickness and the number of inflammatory cells, thus it may be useful for direct application to damaged infected wounds.

Prostate cancer is the most prevalent cancer in men. At present, the diagnosis and screening of prostate cancer rely on the essential biomarker known as prostate-specific antigen (PSA). The main purpose of this study was to develop a novel immunoassay for the detection of PSA based on a tri-part split-nanoluciferase system and a nanobody targeting PSA. In our approach, two small components of the split-nanoluciferase, referred to as β9 and β10, were individually fused to two anti-PSA nanobodies, N7 and N23. When these proteins bind to PSA and in the presence of the third nanoluciferase component, called Δ11S, the split-nanoluciferase components are brought into close proximity, facilitating the reassembly of the active nanoluciferase and activation of luminescence. These proteins were expressed in a bacterial expression system, purified, and employed for the intended immunoassay. The developed immunoassay demonstrated the capability to sensitively detect PSA within a linear range from 1.0 to 20.0 ng/mL with LOD of 0.4 ng/mL, and the results obtained through this immunoassay agreed with those derived from the ELISA. Our study indicates that the homogeneous immunoassay developed with nanobodies exhibits remarkable specificity for PSA and can serve as a reliable, fast, and user-friendly test for detecting PSA.

Renilla luciferase catalyzes the oxidation of coelenterazine to coelenteramide and results in the emission of a photon of light. Although Renilla luciferase has various applications in biotechnology, its low thermal stability limits the development of its applications. Arginine is a well-known stabilizing amino acid that plays a key role in protein stabilization against inactivation. However, its impact on enzyme properties is unpredictable. This study investigates the impact of arginine on the kinetics and thermal stability of Renilla luciferase. The enzyme's performance was significantly enhanced in the presence of arginine, with catalytic efficiency increasing by 3.31-fold and 3.08-fold when exposed to 0.2 M and 0.3 M arginine, respectively. Additionally, arginine improved the thermal stability of Renilla luciferase. Molecular dynamics simulation showed that the addition of 0.2 M arginine reduced the binding of coelenteramide, the reaction product and an enzyme inhibitor, to the active site of the Renilla luciferase. Therefore, the release of the product was accelerated, and the affinity of Renilla luciferase for coelenterazine increased. Furthermore, Molecular dynamics studies indicated an increased network of water molecules surrounding Renilla luciferase in the presence of 0.2 M arginine. This network potentially enhances the hydrophobic effect on the protein structure, ultimately improving enzyme stability. The findings of this study hold promise for the development of commercial kits incorporating Renilla luciferase.