Search the repository

A+ | A- | | SLO | ENG

Abstract: The safety, authenticity, and traceability of food and pharmaceutical products are critical challenges, especially in the context of widespread counterfeiting. Most existing anti-counterfeiting and sensing technologies are applied externally to packaging, making them vulnerable to tampering. A more robust approach is to incorporate them directly into edible products. Whispering-gallery modes (WGMs), highly sensitive optical resonances supported by spherical microcavities, provide a promising platform due to their environmental responsiveness and spectral uniqueness. Here, we demonstrate edible WGM microcavities based on chlorophyll-coated silica microspheres. Monodisperse microspheres exhibit stable WGM resonances under continuous-wave laser excitation, with quality factors ranging from 2,000 to 10,000. Individual microsphere diameters are determined with a precision of approximately 40 nm. When embedded in low-refractive-index agarose matrices, the microspheres generate size-specific spectral signatures that function as optical barcodes and remain stable for at least six months. Based on intrinsic size variations, we further demonstrate edible physical unclonable functions (PUFs) with stable and unique optical identifiers. In addition, the microcavities enable sugar concentration measurements with uncertainties as low as 0.23 percentage points and pH sensing with an accuracy of approximately 0.3 pH units, when embedded in a pH-responsive hydrogel. These results establish edible WGM microcavities as a multifunctional platform for secure labeling, sensing, and anti-counterfeiting in consumable products.
Keywords: edible materials, whispering gallery modes, optical barcodes, physical unclonable functions, sensors
Published in DiRROS: 29.07.2026; Views: 97; Downloads: 72
Full text (1,89 MB)
This document has many files! More...

Abstract: This article provides comprehensive methodological guidance for implementing rotating magnetic nanochain-enhanced lateral flow immunoassays with volumetric magnetic detection. Rotating magnetic nanochains act as microscale stirrers that substantially enhance antibody-antigen binding kinetics through convective mixing, yet their integration into lateral flow platforms presents unique technical challenges requiring both computational optimization and specialized characterization. We describe complete workflows for: (i) computational fluid dynamics modeling using COMSOL Multiphysics to simulate nanochain rotation, fluid flow, and mass transport enhancement; (ii) electron microscopy characterization of magnetic nanochain morphology and size distributions; (iii) rotating magnetic field generator design and operation; and (iv) magnetic particle quantification measurement procedures for volumetric signal readout. Each section provides step-by-step instructions with sufficient detail to enable independent replication. The described methods enable development of lateral flow assays achieving sub-nanogram detection limits with rapid (6-minute) analysis times, addressing critical needs in point-of-care diagnostics. These methods complement our related research article in Biosensors and Bioelectronics by providing the technical foundation necessary for adoption and adaptation of this technology by other laboratories.
Keywords: magnetic nanochains, lateral flow immunoassay, computational fluid dynamics, point-of-care diagnostic, rotating magnetic field, cardiac biomarkers
Published in DiRROS: 20.05.2026; Views: 239; Downloads: 270
Full text (5,94 MB)
This document has many files! More...

Abstract: The thorough understanding of the interactions between nanoparticles and lipid membranes has attracted major interest over the past few decades. This spans fundamental biophysics and biomechanics, as well as medical applications, where nanoparticles could serve as potential drug carriers. The influence of the lipid phase in these interactions has been studied to markedly less extent with respect to the nanoparticle size, shape and coating, as well as the presence of electric charge in either the nanoparticles or the membranes. Seeking to gain new insights into the lipid phase, we have systematically investigated the role of the liquid-disordered, the gel-ordered, as well as the seldom-studied ripple phases in modulating the interaction strength between nanoparticles and biomimetic membranes. Supported lipid vesicles and supported lipid bilayers of different composition and amount of electric charge, as well as spherical functionalized Au nanoparticles with and without charge have formed our experimental platform. The results, obtained by quartz crystal microbalance with dissipation monitoring and complemented by atomic force microscopy, reveal a strikingly different mechanistic picture of the interactions between the various lipid phases and types of nanoparticles. We demonstrate enhanced vesicle rupture in the case of stiffer membranes, consistent with recent theoretical studies, yet supported by limited existing experimental evidence. This work advances fundamental understanding of lipid-state-driven nanoparticle–membrane interactions. Such insight is essential, as dynamic changes in bilayer rigidity, composition, and surface charge determine how membranes and nanoparticles interact.
Keywords: supported lipid vesicles, supported lipid bilayers, gold nanoparticles, lipid phase, quartz crystal microbalance with dissipation monitoring (QCM-D), nanoparticle-membrane interactions
Published in DiRROS: 10.04.2026; Views: 361; Downloads: 241
Full text (5,65 MB)
This document has many files! More...

Abstract: Introduction: High-intensity pulsed electromagnetic fields (HI-PEMF) can be used to trigger contactless permeabilization of the plasma membrane similar to electroporation (EP). The permeabilization efficiency and gene delivery by HI-PEMF in vitro are currently inferior to EP. It was suggested that the methodology can be improved with conductive gold nanoparticles (AuNPs), which are reported to amplify the induced electric field in close proximity to the cell membrane. Objectives: Therefore, in this work, we have studied different NPs, which varied in material/conductivity (gold and silica), size (10–50+ nm), shape (i.e., round and rods), concentration (50–200 µg/mL), and functionalization (pegylated or not), and combined them with HI-PEMF (6.7 T × 100 pulses, 1 Hz). Methods: The normal Chinese hamster ovary cell line (CHO) and the cancer human urinary bladder’s transitional carcinoma cell line (T24) were used as a model. We have characterized cell membrane permeabilization using propidium iodide (PI) and the efficacy of gene delivery using pEGFP-N1. Results: Larger NPs and higher NP concentrations resulted in up to a 10% increase in membrane permeability. In contrast, semispherical and rod-shaped AuNPs did not further enhance permeabilization efficiency. Gene delivery efficiency increased from 3% in control samples to 6% in the presence of 50 nm AuNPs. Overall, CHO cells were more susceptible to HI-PEMF-induced effects than T24 cells. Conclusions: This study shows the potential to increase gene delivery efficacy by combining HI-PEMF treatment with conductive NPs. However, it was concluded that the HI-PEMF-induced effects are highly dependent on the cell line, NP type, and concentration and therefore require further investigation.
Keywords: gene delivery
Published in DiRROS: 24.02.2026; Views: 510; Downloads: 316
Full text (1,50 MB)
This document has many files! More...

Abstract: Biofilms, structured communities of microbial cells embedded in extracellular polymeric substances, are notorious for their resilience against conventional antimicrobial treatments. They contribute significantly to chronic infections and industrial biofouling, necessitating innovative strategies for their eradication. Magnetic iron oxide nanoparticles have emerged as a promising tool in combating biofilms due to their biocompatibility and unique physicochemical properties, which enable magnetic delivery of antibacterial agents, magnetic hyperthermia, magneto-mechanical actuation including mechanical biofilm disruption, and reversible dynamic magnetic assembly into hierarchical structures. This review describes developing stages of magnetic nanoscale weapons against biofilms ranging from individual iron oxide nanoparticles to complex hierarchical nanoparticle assemblies in the form of magnetic robots and their swarms. A vast array of possible antibiofilm and antibacterial functionalities originating from iron ions, individual iron oxide nanoparticles, spherical nanoparticle assemblies, magnetic robots, and swarms of robots are presented. Magnetic nanotools offer significant improvements and advantages over conventional methods for biofilm eradication, yet their successful future applications depend on addressing and overcoming critical material, biological, and engineering challenges.
Keywords: biofilm, magnetic nanoparticles, magneto-mechanical actuation, microrobots, nanorobots
Published in DiRROS: 13.01.2026; Views: 551; Downloads: 617
Full text (6,12 MB)
This document has many files! More...