Pukyong National University

White spot syndrome virus (WSSV), the causative agent of white spot disease (WSD), is a major threat to global shrimp aquaculture. Regular WSSV monitoring is essential for disease management, and severity grades may serve as indicators for evaluating shrimp health and anticipating the risk of outbreaks. This study aimed to elucidate the relationships among WSSV replication properties, severity grades, and disease transition dynamics in whiteleg shrimp using an intramuscular challenge (Exp. 1) to establish a controlled infection and immersion challenge (Exp. 2) to simulate the natural transmission. In Exp. 1, severity grades were associated with distinct viral replication phases, with the eclipse, logarithmic, and plateau phases corresponding to G0-G1, G2-G3, and G4 grades. In Exp. 2, the transition rate from asymptomatic to ill (λ_ai) peaked at 40-48 h post-infection (hpi, 0.24), approximately 24 h earlier than the transition from ill to deceased (λ_id) at 64-72 hpi (0.28). Collectively, shrimp remained asymptomatic but shed virus during the eclipse phase (G0-G1; 0-48 hpi), whereas anorexia and moribundity appeared during the logarithmic phase (G2-G3; 48-72 hpi), followed by extensive mortality in the plateau phase (G4; 72-120 hpi). Accordingly, the results of the present study suggest that shrimp exhibiting G0-G1 grades are likely to represent chronic infection, whereas grades ≥ G2 indicate ongoing disease progression. The correlations identified between severity grades and disease transition provide a practical framework for interpreting longitudinal WSSV monitoring data and improving risk assessment and management in shrimp aquaculture.

Transdermal drug delivery systems (TDDS) using microneedles (MNs) patches have shown promise for improved therapeutic outcomes. In this study, acyclovir (ACV)-loaded MNs patches for herpes simplex virus (HSV) therapy were prepared using mungbean starch (MBS), polyvinyl alcohol (PVA), and plasticizers (arginine and mannitol), and their physicochemical properties, ACV release behavior, antimicrobial activity, and biodegradation, cell viability, and antiviral efficacy were investigated. The MNs exhibited compression forces of 1.30 - 4.80 N/needle and a pyramidal square shape with a length of 620-640 μm, ensuring efficient skin penetration. The ACV release (%) from the ACV-loaded MNs patches during an artificial skin test was found to be 2.50 - 4.32 times higher than that from ACV-loaded biomaterial as the film-type formulation. Additionally, over 98.0 % of ACV was released from the prepared MNs patches within 80 min. The ACV release mechanism was analyzed using zero-order, first-order, Higuchi, Fickian diffusion, and Korsmeyer-Peppas models, which revealed a Fickian diffusion mechanism. Visualization of intradermal drug release were conducted using ACV- and riboflavin-loaded MNs patches on agar blocks and pig ears/agar block models. Biodegradability, cell viability, and antiviral studies further demonstrated the potential of MNs patches as a TDDS. These results suggest that the prepared MNs patches are promising candidates for transdermal HSV therapy.

Catheter-associated urinary tract infections (CAUTIs) are a serious global concern due to the emergence of drug-resistant bacteria and the biofilm formation on urinary catheters (UCs). Surface modification strategies have been identified as a prominent and cost-effective method to address this issue owing to its tunable properties, which effectively combat the biofilm formation on UCs. This study reports the development of a hydrophobic-silver nanoparticles (Ag NPs) decorated tannic acid-based coating on silicone UC using a layer-by-layer (LBL) approach that can effectively eradicate Escherichia coli (E. coli) biofilms. The LBL coating (PFDT-Ag-Dex) consists of a tannic acid (TA)-(3-aminoprophyl) triethoxysilane (APTES) NPs deposition, followed by Ag NPs decoration and 1H,1H,2H,2H-perfluorodecane-thiol (PFDT) layers, which impart the hydrophobicity, biocompatibility, antibacterial activity, and coating adhesion, respectively. Formation of the LBL coating on the Si catheter was successfully confirmed through extensive characterizations. In vitro and in vivo investigations showed that the PFDT-Ag-Dex coated Si catheter significantly inhibited the E. coli biofilm formation with ∼95 % efficiency due to the combined effects of the hydrophobic properties, tannic acid and Ag⁺ ions causing the cell membrane disruption. Furthermore, in vivo studies using mouse and rabbit animal models confirmed the biosafety of the PFDT-Ag-Dex-coated Si catheter, which exhibited a negligible inflammatory response. The studies suggest that the Ag-TA-hydrophobic coated catheter is a promising solution for combating the urinary tract infections.