1. The effect of surface roughness on the Er:YAG laser-induced photoacoustic removal of bacteria in zero-gap periodontal/peri-implant pocket modelDominik Šavli, Marko Volk, Katja Molan, Saša Terlep, Špela Levičnik Hoefferle, Aleš Babnik, Mojca Trost, Boris Gašpirc, Matjaž Lukač, David Stopar, Matija Jezeršek, 2025, original scientific article Abstract: Effective biofilm removal from periodontal and peri-implant pockets remains a challenge due to constrained geometry and limited access. This study investigates a novel phenomenon of distant-field cleaning utilizing Er:YAG laser treatment, where removal of bacteria occurs in areas without previously observed cavitation under high-speed imaging. To understand this effect, we developed a transparent zero-gap model simulating a tooth or implant and surrounding soft tissue. We systematically examined the impact of laser fiber insertion depth, cavitation bubble dynamics, the stiffness and roughness of the material, and laser parameters on the cleaning efficiency. Our findings reveal that the removal of bacteria indeed correlates strongly with cavitation occurrence. Deeper optical fiber insertion into the pocket model only enhanced cleaning efficiency by moving the fluid dynamics and enabling deeper water penetration. Surprisingly, high-speed imaging showed no cavitation in distant regions, raising questions about the mechanisms enabling such cleaning. Further investigation uncovered that surface roughness played a critical role in facilitating this distant-field effect. The smooth, transparent surfaces used in imaging experiments suppressed fluid dynamics, while textured surfaces created by 3D-printed molds and bacterial monolayer allowed deeper water penetration and pressure wave propagation. These surface irregularities enabled localized cavitation events and enhanced bacterial disruption, even in regions beyond the laser fiber’s immediate influence. This study emphasizes the significance of surface roughness in test models, highlighting the need for models to closely mimic the conditions of real clinical scenarios for accurate optimization of Er:YAG laser-induced photoacoustic removal of bacteria.
Keywords: Er:YAG laser, cavitation dynamics, biofilm removal, surface roughness, photoacoustic cleaning, periodontal and peri-implant pockets, secondary cavitation
Published in DiRROS: 20.04.2026; Views: 6; Downloads: 5
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2. Development and field testing of a cavitation-based robotic platform for sustainable in-water hull cleaningUroš Puc, Andreja Abina, Edvin Salvi, Vlado Malačič, Janja Francé, Riccardo Zanelli, Aleksander Zidanšek, 2026, original scientific article Abstract: Biofouling on ship hulls significantly increases hydrodynamic drag, fuel consumption, and greenhouse gas emissions, while also facilitating the spread of invasive species in regional and global waters, thereby threatening marine biodiversity. To address these environmental and economic issues, we developed an innovative robotic platform for in-water hull cleaning. The platform utilizes a cavitation-based cleaning module that removes biofouling while minimizing hull surface damage and preventing the spread of detached particles into the marine environment. This paper describes the design, operation, and testing of a developed robotic cleaning system prototype. Emphasis is placed on integrating components and sensors for continuous monitoring of key seawater parameters (temperature, salinity, turbidity, dissolved oxygen, chlorophyll-a, etc.) before, during, and after underwater cleaning. Results from real-sea trials show the platform’s effectiveness in removing biofouling and its minimal environmental impact, confirming its potential as a sustainable solution for in-water hull cleaning.
Keywords: biofouling, ship hulls, in-water cleaning, undewater robot, sensor integration, field testing
Published in DiRROS: 27.01.2026; Views: 269; Downloads: 169
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3. Simple and fast wettability control of aminosilanized surfaces with carboxylic acidsAndraž Černoga, Jelena Papan Djaniš, Darja Lisjak, Jernej Iskra, Griša Grigorij Prinčič, 2025, original scientific article Keywords: reverse wettability, aminosilane, ion pair, self-cleaning surface
Published in DiRROS: 27.10.2025; Views: 500; Downloads: 263
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5. Functionalisation of the aluminium surface by cucl2 chemical etching and perfluoro silane grafting : enhanced corrosion protection and improved anti-icing behaviourPeter Rodič, Matic Može, Iztok Golobič, Ingrid Milošev, 2024, original scientific article Abstract: This study aimed to prepare a facile hierarchical aluminium surface using a two-step process consisting of chemical etching in selected concentrations of CuCl2 solution and surface grafting through immersion in an ethanol solution containing 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane. The goal was to achieve superhydrophobic characteristics on the aluminium surface, including enhanced corrosion resistance, efficient self-cleaning ability, and improved anti-icing performance. The surface characterisation of the untreated aluminium and treated in CuCl2 solutions of different concentrations was performed using contact profilometry, optical tensiometry, and scanning electron microscopy coupled with energy dispersive spectroscopy to determine the surface topography, wettability, morphology, and surface composition. The corrosion properties were evaluated using potentiodynamic measurements in simulated acid rain solution and salt-spray test according to ASTM B117-22. In addition, self-cleaning and anti-icing tests were performed on superhydrophobic surfaces prepared under optimal conditions. The results showed that the nano-/micro-structured etched aluminium surface with an optimal 0.5 M concentration of CuCl2 grafted with a perfluoroalkyl silane film achieved superhydrophobic characteristics, with water droplets exhibiting efficient corrosion protection, self-cleaning ability, and improved anti-icing performance with decreased ice nucleation temperature and up to 545% increased freezing delay.
Keywords: superhydrophobic surface, corrosion protection, self-cleaning, anti-icing
Published in DiRROS: 23.04.2025; Views: 816; Downloads: 510
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6. Use of hydrodynamic cavitation in (waste)water treatmentMatevž Dular, Tjaša Griessler Bulc, Ion Gutiérrez-Aguirre, Ester Heath, Tina Kosjek, Aleksandra Krivograd-Klemenčič, Martina Oder, Martin Petkovšek, Nejc Rački, Maja Ravnikar, Andrej Šarc, Brane Širok, Mojca Zupanc, Miha Žitnik, Boris Kompare, 2016, original scientific article Abstract: The use of acoustic cavitation for water and wastewater treatment (cleaning) is a well known procedure. Yet, the use of hydrodynamic cavitation as a sole technique or in combination with other techniques such as ultrasound has only recently been suggested and employed.
In the first part of this paper a general overview of techniques that employ hydrodynamic cavitation for cleaning of water and wastewater is presented.
In the second part of the paper the focus is on our own most recent work using hydrodynamic cavitation for removal of pharmaceuticals (clofibric acid, ibuprofen, ketoprofen, naproxen, diclofenac, carbamazepine), toxic cyanobacteria (Microcystis aeruginosa), green microalgae (Chlorella vulgaris), bacteria (Legionella pneumophila) and viruses (Rotavirus) from water and wastewater.
As will be shown, hydrodynamic cavitation, like acoustic, can manifest itself in many different forms each having its own distinctive properties and mechanisms. This was until now neglected, which eventually led to poor performance of the technique. We will show that a different type of hydrodynamic cavitation (different removal mechanism) is required for successful removal of different pollutants.
The path to use hydrodynamic cavitation as a routine water cleaning method is still long, but recent results have already shown great potential for optimisation, which could lead to a low energy tool for water and wastewater cleaning.
Keywords: wastewater, cleaning, hydrodynamic cavitation, pharmaceuticals, cyanobacteria, microalgae, viruses, Legionella bacteria
Published in DiRROS: 25.07.2024; Views: 1135; Downloads: 674
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7. Photo, thermal and photothermal activity of ▫$TiO_2$▫ supported Pt catalysts for plasmon-driven environmental applicationsGregor Žerjav, Zafer Say, Janez Zavašnik, Matjaž Finšgar, Christoph Langhammer, Albin Pintar, 2023, original scientific article Abstract: TiO2+Pt plasmonic solids with 1 wt% Pt and different TiO2 supports (anatase nanoparticles (TNP), polycrystalline nanorods (a-TNR) and single-crystal anatase nanorods (TNR)) were synthesized using the wet impregnation technique and tested as photo, thermal and photothermal catalysts in gas-solid and gas-liquid-solid reactions. Due to the different charges of the TiO2 support surfaces, Pt particles with different sizes, crystallinities and degrees of interaction with the TiO2 supports were formed during the synthesis. The heights of the Schottky barrier (SBH) were 0.38 eV for the a-TNR+Pt, 0.41 eV for the TNP+Pt, and 0.50 eV for the TNR+Pt samples, respectively. The low visible-light-triggered photocatalytic activity of the TNR+Pt catalyst toward the oxidation of water-dissolved bisphenol A (BPA) is attributed to its high SBH and active site deactivation due to the adsorption of BPA and/or BPA oxidation products. The highest photothermal catalytic H2-assisted NO2 reduction rate was expressed by the TNR+Pt catalyst. This can be ascribed to the presence of a narrow particle size distribution of small Pt particles, the absence of the Pt catalysed reduction of the TNR support at higher temperatures, and the lower rate of re-injection of “hot electrons” from the TNR support to the Pt particles.
Keywords: heterogeneous photocatalysis, titanium dioxide, plasmonic noble metal, platinum particles, visible light illumination, Schottky barrier height, bisphenol A, wastewater treatment, NOx abatement, air cleaning, microreactor, thermal catalysis, photothermal catalysis
Published in DiRROS: 23.06.2023; Views: 2158; Downloads: 1041
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