Anomalous diffusion of nanoparticles in the spatially heterogeneous biofilm environment.

Biofilms contain extracellular polymeric substances (EPS) that provide structural support and restrict penetration of antimicrobial treatment. To overcome limited penetration, functionalized nanoparticles (NPs) have been suggested as carriers for antimicrobial delivery. Using microscopy, we evaluate the diffusion of nanoparticles in function of the structure of Salmonella biofilms. We observe anomalous diffusion and heterogeneous mobility of NPs resulting in distinct NPs distribution that depended on biofilm structure. Through Brownian dynamics modeling with spatially varying viscosity around bacteria, we demonstrated that spatial gradients in diffusivity generate viscous sinks that trap NPs near bacteria. This model replicates the characteristic diffusion signature and vertical distribution of NPs in the biofilm. From a treatment perspective, our work indicates that both biofilm structure and the level of EPS can impact NP drug delivery, where low levels of EPS might benefit delivery by immobilizing NPs closer to bacteria and higher levels hamper delivery due to shielding effects.

Nutritional status in patients with hepatocellular carcinoma: Potential relevance for clinical outcome.

BACKGROUND: Impaired nutritional status is a risk factor for unfavorable outcome in cirrhosis. METHODS: In this prospective cohort study in hepatocellular carcinoma patients referred for tumor-specific therapy, nutritional status was assessed before and 3 months post-treatment using 4 complementary tools: hand-grip strength (HGS), Liver Frailty Index (LFI), Patient-Generated Subjective Global Assessment (PG-SGA) and skeletal muscle index (L3-SMI). Uni- and multivariable analyses were performed using Kaplan Meier curves and Cox's regression analyses with correction for Barcelona Clinic Liver Cancer (BCLC) stage, alpha-fetoprotein and age. RESULTS: 56 patients were evaluated at baseline and 38 patients 3 months post-treatment. Baseline BCLC stage was 0 in 14%, A in 27%, B in 36%, C in 21%, and D in 2%. HGS, LFI, PG-SGA and L3-SMI were impaired in 13%, 95%, 21% and 71% respectively. Of all patients, 52% died after (median, range) 373 (32-962) days. Of the nutritional assessment tools, only HGS was independently associated with complication-free survival (HR 0.304, 95%CI 0.10-0.88: p = 0.028) and, approaching significance, with overall survival (HR 0.323, 95%CI 0.103-1.008: p = 0.052). Tumor-specific therapy was administered in 50 patients (20% radiofrequency / microwave ablation, 4% resection, 74% transarterial radio- or chemoembolization, 2% sorafenib). Three months post-treatment, complete response occurred in 44%, partial response in 20%, stable disease in 20% and progressive disease in 16%. Child-Pugh scores deteriorated and such deterioration was independently associated with reduced overall and complication-free survival. CONCLUSIONS: reduced baseline HGS and deteriorated post-treatment Child-Pugh score are associated with reduced overall and complication-free survival in HCC.