Glioblastoma is one of the most aggressive tumours with a poor response to treatment and a poor prognosis for patients. One of the proteins expressed in glioblastoma tissue is CHI3L1 (YKL-40), which is upregulated and known for its angiogenesis-supporting and pro-tumour immunomodulatory effects in a variety of cancers. In this paper we present the anti-angiogenic, anti-migratory and immunomodulatory effects of the compound G721-0282, an inhibitor of CHI3L1. The inhibitor-induced changes were investigated using conventional techniques as well as the novel label-free digital holographic tomography (DHT), a quantitative phase imaging technique that allows the reconstruction of the refractive index (RI), which is used as an image contrast for 3D visualisation of living cells. DHT allowed digital staining of individual cells and intercellular structures based only on their specific RI. Quantitative spatially resolved analysis of the RI data shows that the concentration of G721-0282 leads to significant changes in the density of cells and their intracellular structures (in particular the cytoplasm and nucleus), in the volume of lipid droplets and in protein concentrations. Studies in the U-87 MG glioblastoma cell line, THP-1 monocytes differentiated into macrophages, human microvascular endothelial cells (HMEC-1) and in the spheroid model of glioblastoma composed of U-87 MG, HMEC-1 and macrophages suggest that inhibition of CHI3L1 may have potential in the antitumour treatment of glioblastoma. In this paper, we also propose a spheroid model for in vitro studies that mimics this type of tumour.

The prevention of biofilm formation is crucial for the limitation of bacterial infections typically associated with postoperative infections, complications in bedridden patients, and a short-term prognosis in affected cancer patients or mechanically ventilated patients. Antimicrobial photodynamic therapy (aPDT) emerges as a promising alternative for the prevention of infections due to the inability of bacteria to become resistant to aPDT inactivation processes. The aim of this study was to demonstrate the use of a functionalized combination of Chlorin e6 and Pheophorbide as a new approach to more effective aPDT by increasing the accumulation of photosensitizers (PSs) within Escherichia coli cells. The accumulation of PSs and changes in the dry mass density of single-cell bacteria before and after aPDT treatment were investigated by digital holotomography (DHT) using the refractive index as an imaging contrast for 3D label-free live bacteria cell imaging. The results confirmed that DHT can be used in complex examination of the cell–photosensitizer interaction and characterization of the efficiency of aPDT. Furthermore, the use of Pheophorbide a as an efflux pomp inhibitor in combination with Chlorin e6 increases photosensitizers accumulation within E. coli and overcomes the limited penetration of Gram-negative cells by anionic and neutral photosensitizers.

The increase in bacterial resistance to antibiotics in recent years demands innovative strategies for the detection and combating of biofilms, which are notoriously resilient. Biofilms, particularly those on contact lenses, can lead to biofilm-related infections (e.g., conjunctivitis and keratitis), posing a significant risk to patients. Non-destructive and non-contact sensing techniques are essential in addressing this threat. Digital holographic tomography emerges as a promising solution. This allows for the 3D reconstruction of the refractive index distribution in biological samples, enabling label-free visualization and the quantitative analysis of biofilms. This tool provides insight into the dynamics of biofilm formation and maturation on the surface of transparent materials. Applying digital holographic tomography for biofilm examination has the potential to advance our ability to combat the antibiotic bacterial resistance crisis. A recent study focused on characterizing biofilm formation and maturation on six soft contact lens materials (three silicone hydrogels, three hydrogels), with a particular emphasis on Staphylococcus epidermis and Pseudomonas aeruginosa, both common culprits in ocular infections. The results revealed species- and time-dependent variations in the refractive indexes and volumes of biofilms, shedding light on cell dynamics, cell death, and contact lens material-related factors. The use of digital holographic tomography enables the quantitative analysis of biofilm dynamics, providing us with a better understanding and characterization of bacterial biofilms.

ANTIMICROBIAL RESISTANCE: especially via efflux pump-mediated multidrug resistance is a major factor limiting antibacterial therapy efficacy. Antimicrobial photodynamic therapy (aPDT) is a non-antibiotic strategy that overcomes resistance through generation of reactive oxygen species. Plant-derived compounds exhibit efflux pump inhibitory activity and potential photosensitizing capabilities. This study evaluated the use of plant-derived efflux pump inhibitors (EPIs): berberine, capsaicin, coumarin 6, curcumin, palmatine, and piperine in combination with Chlorin e6 and aPDT against Bacillus cereus (Gram-positive) and Escherichia coli (Gram-negative). The aim was to enhance Chlorin e6 accumulation and reduce bacterial dry mass density. Both qualitative and quantitative methods were used in the study. Minimum inhibitory concentrations (MICs) of EPIs were determined to guide treatment concentrations. A modified resazurin assay assessed bacterial viability after 24-h incubation with EPIs. Spectroscopic properties of all compounds were recorded using UV-VIS spectroscopy. Digital holotomography (DHT) was applied to monitor changes in refractive index (RI) of bacterial cells induced by incubation and treatment, and results were validated using confocal fluorescence microscopy. Changes in RI values indicated structural and compositional changes in the bacteria. Naturally derived EPIs effectively potentiated aPDT by promoting photosensitizer uptake and induced a measurable reduction in dry mass density. Treatment efficacy using combination therapy for B.cereus and E.coli improved 273.90 % and 227.72 %, respectively. These findings suggest naturally derived EPIs effectively potentiate Chlorin e6-mediated aPDT and improve bactericidal capacity against bacteria. The study offers mechanistic insight into photodynamic enhancement via plant-based inhibitors and supports potential applications in clinical antimicrobial therapy, food safety, and industrial decontamination.