Antimicrobial photodynamic therapy (aPDT) was demonstrated to be effective against various species of Gram-positive bacteria. However, the complex structure of a Gram-negative bacteria envelope limits the application of aPDT. Thus, the goal of this study was to improve the efficiency of antimicrobial photodynamic therapy with Fotoditazin against uropathogenic Gram-negative bacteria. The non-ionic detergent Triton X-100 and emulsifier Tween 80 were tested. The effect of extracellular photosensitizer on aPDT efficacy was analyzed. Moreover, the irradiation regime was optimized in terms of the output power and emitting mode. It was found that Triton X-100 at 10% vol enhanced the efficacy of aPDT of E. coli up to 52%. The subsequent observation demonstrated that, when the photosensitizer was removed from the extracellular space, the efficacy of aPDT on various Gram-negative species decreased dramatically. As for the irradiation mode, an increase in the laser output power led to an increase in the aPDT efficacy. The pulsed irradiation mode did not affect the aPDT efficacy. Thus, in order to achieve optimal aPDT efficacy, bacteria should be irradiated at 450-mW output power in the presence of Triton X-100 and a photosensitizer in the extracellular environment. However, it should be noted that the efficacy of aPDT of K. pneumoniae was significantly lower than for other species. The developed aPDT technique may be effective in a native environment of uropathogenic microorganisms.

The liver’s regenerative capacity is essential for resection and transplantation, but chronic liver diseases compromise this ability. Conventional preoperative tests poorly predict regeneration in diseased livers, necessitating new intraoperative tools. Optical coherence tomography (OCT) provides real-time high-resolution “optical biopsy” and functional tissue assessment, making it a promising method for evaluating liver regenerative potential. The aim of this study was to identify characteristic criteria derived from MM OCT that could be used intraoperatively to detect the presence and type of pathology, and to assess the reduction in liver regenerative potential in patients. In this study, we used intraoperative multimodal OCT (MM OCT)—combining attenuation mapping and elastography—for real-time, label-free assessment of changes in liver structure, and stiffness during regeneration. MM OCT also provides higher resolution and specificity than conventional clinical imaging. In a rat model, we induced steatosis by high-fat diet and fibrosis by CCl₄ injections, then induced regeneration by 70% partial hepatectomy (PH). MM OCT monitoring was performed on day 0 (pre-PH), day 3, and day 7 (post-PH). Pathologies and regeneration were verified by biochemical blood tests, histological analysis, and real time-PCR for steatosis- and fibrosis-specific genes. As a result, attenuation coefficient and Young’s modulus obtained by MM OCT enable real-time assessment of liver tissue changes in steatosis and fibrosis, which vary with regeneration stage. Steatosis showed uniformly high attenuation and low stiffness before and after resection. Fibrosis exhibited heterogeneous attenuation and marked stiffness fluctuations—high pre-resection values dropped at day 3 and rose again by day 7. Attenuation coefficient detects lipid droplets in hepatocytes and identifies high-density hepatocyte zones near collagen septa, distinguishing them from densely packed unaltered cells. Thus, MM OCT identifies pathology type, lipid infiltration and collagen presence—features that serve as indicators of impaired liver regenerative capacity.

Background/Objectives: Although immune checkpoint inhibitors (ICIs) have dramatically transformed the landscape of cancer treatment, a significant percentage of patients are resistant to therapy. Identifying biomarkers to accurately predict patient response prior to treatment remains one of the key challenges in this field. Our study aimed to develop a platform for personalized prediction of immunotherapy efficacy for melanoma using isolated lymphocytes and fluorescence lifetime imaging (FLIM) of their autofluorescence. Methods: At the first stage, the ability of FLIM of the autofluorescent coenzyme NAD(P)H to resolve cellular response to anti-CTLA-4 was tested on lymphocytes isolated from lymphatic nodes (LNs) of mice with the B16 melanoma model. Then, cellular metabolic shifts in response to treatment with anti-PD-1 or its combination with anti-CTLA-4 were assessed via FLIM of patients’ blood lymphocytes. Activation of T-cells and alterations in the expression of metabolic genes after the treatment in vitro were additionally evaluated. Results: Fluorescence decay parameters α₁ (free NAD(P)H fraction) and τ₂ (protein-bound NAD(P)H lifetime) were identified as sensitive markers of lymphocyte activation after the treatment with immune checkpoint inhibitors. Responsive samples exhibited an increase in these parameters, which was associated with metabolic reprogramming toward more active glycolysis, the TCA cycle, fatty acid oxidation (FAO) and synthesis, the pentose phosphate pathway (PPP) and mitochondrial biogenesis. Importantly, the in vitro response of primary lymphocytes isolated prior to treatment correlated well with subsequent clinical outcomes. Conclusions: The proposed platform represents a promising solution for patient-specific immunotherapeutic drug screening and personalized treatment optimization.