Bioinseneeria instituut

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Effects of Disruption of Genes With Unknown Function in the C1-Fixing Gene Cluster on a Gas-Fermenting Acetogen
(Tartu Ülikool, 2025) Vorontsova, Mariia; Valgepea, Kaspar, juhendaja; Nwaokorie, Ugochi Jennifer, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Gas fermentation is a promising technology for producing chemicals, fuels, and feed proteins from greenhouse gases and solid waste using gas-fermenting microbes. Acetogens are the most attractive biocatalysts for gas fermentation as they can use C1 gases carbon monoxide (CO) and carbon dioxide (CO2) as their sole carbon source using the Wood-Ljungdahl pathway (WLP). Genes encoding WLP enzymes are located in a C1-fixing gene cluster that also contains several genes with unclear function. In this work, the role of two such genes were investigated through gene disruption in the model-acetogen Clostridium autoethanogenum. For this, CRISPR/Cas9n plasmids were constructed and used for knock-out (KO) of the glycine cleavage system H protein (gcvH) and double knock-out (dKO) of gcvH and the first 80 bp of the adjacent acsV gene. Phenotypic characterisation of ∆gcvH in autotrophic batch cultures revealed significant growth defects and altered yields of acetate and 2,3-butanediol (2,3-BDO) compared to the parental LAbrini strain. Additionally, ∆gcvH showed a very long lag phase during growth without yeast extract. Supplementing cultures with glycine shortened the lag phase but did not restore normal growth, suggesting gcvH involvement in glycine synthesis. Notably, the dKO ∆gcvH∆acsV strain failed to grow autotrophically and phenotypic characterisation of heterotrophic batch cultures revealed significant growth defects and higher 2,3-BDO and ethanol product yields compared to LAbrini. Our findings shed light on the potential links between the glycine cleavage system and WLP and contribute towards a better understanding of carbon fixation in acetogens.
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Characterization of Microbial Community Present on Communal Surfaces with Antimicrobial Coatings
(Tartu Ülikool, 2025) Mehraliyeva, Laman; Ivask, Angela, juhendaja; Harleen Kaur, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Microbial contamination on high-touch communal surfaces poses a risk to human health. While traditional cleaning methods such as disinfection and washing are commonly used, they may be limited by human error, reduced microbial susceptibility, or the need for frequent reapplication. Antimicrobial coatings offer a promising alternative by providing persistent protection through mechanisms that inhibit microbial growth or attachment. Copper is one of the most frequently present materials in currently marketed antimicrobial coatings. The main aim of this study was to examine the bacterial communities on the handles of shopping baskets covered with metallic copper and to compare them with handles that had no copper surfaces. Microorganisms were collected from the handles using moistened cotton swabs, and the collected samples were used to count aerobically growing bacterial colonies. To eliminate the DNA of non-viable bacterial cells from community analysis, propidium monoazide dye (PMA), which is expected to bind the DNA of dead or heavily damaged bacteria, was added to part of the samples. Then, DNA was extracted from the samples, and sequencing libraries were constructed. The microbial communities on surfaces were identified through sequencing of the 16S rRNA variable region and analyzed using statistical tools. The results showed that basket handles coated with copper had significantly fewer aerobically growing bacterial colonies and lower species richness compared to the handles without copper surfaces. Additionally, the microbial taxa present on the surface differed from those found on uncoated handles. Treatment of the surface-collected microbial communities with PMA further influenced the composition of the microbiome. These findings suggest that copper-based antimicrobial coatings may reduce microbial burden and diversity on surfaces, and that PMA treatment is a valuable tool to use in experiments for differentiating between live and dead or significantly damaged microbes in DNA-based studies.
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Combinatorial Effect of Histone H3 and H4 Mutations with Deletion of YEATS Domain Protein Sas5 in Saccharomyces cerevisiae
(Tartu Ülikool, 2025) Dey, Noah Jabis; Värv, Signe, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
The single cell eukaryote, Saccharomyces cerevisiae or budding yeast, synthesizes three YEATS domain containing proteins associated with chromatin remodelling and modifying complexes. Previous experiments have shown that deletion of either of the YEATS domain containing proteins, Taf14 or Yaf9, in combination with mutations in the N-terminal tails of histones H3 and H4 is lethal for the cells. In this thesis the aim was to assess the effects of deletion of SAS5, the third YEATS-domain containing protein, in combination with mutations in histones. A decrease in the viability for cells carrying sas5Δ and H3 acetylation and methylation mutations was detected.
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Iron and Nitrogen Doped Hierarchical Porous Lignin-Derived Carbons as Oxygen Reduction Reaction Electrocatalysts
(Tartu Ülikool, 2025) Meira Chaves Barbalho, Vitor; Lilloja, Jaana, juhendaja; Tammeveski, Kaido, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Non-precious metal Fe-N-C electrocatalysts, which can be used as cathode materials for oxygen reduction reaction in an anion-exchange membrane fuel cell were synthesized and investigated by electrochemical and physicochemical methods. The carbon, iron, and nitrogen precursors used to synthesize the electrocatalysts were lignin, iron(II) acetate, and 1,10-phenanthroline, respectively. To obtain the hierarchical porous carbon support, lignin was carbonized using magnesium nitrate hexahydrate as template via high-temperature pyrolysis. Several pyrolysis temperatures (800-1100 °C) were employed to find the optimal carbonization temperature. Iron and nitrogen doping was performed for all carbon materials through flash pyrolysis at 800 °C. The electrocatalytic performance of the prepared Fe-N-C catalyst materials toward the oxygen reduction reaction was studied and compared using the rotating disk electrode method. The physicochemical properties of the catalyst materials were investigated by various analytical methods, namely scanning electron microscopy, scanning transmission electron microscopy, N2 physisorption, X-ray photoelectron spectroscopy, and Raman spectroscopy.
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Robotic Vision of Social Humanoid Robot SemuBot
(Tartu Ülikool, 2025) Mammadov, Sahib; Zinatullin, Leonid, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Social robots can be used in areas such as healthcare, education, and customer service due to their ability to interact socially. They aim to interact customizably, emotionally, and intelligently to promote trust, comfort, and induce real engagement. For effective interaction with people, a social robot has to identify and interpret human facial features such as age, gender, gaze, and emotive expressions. In this thesis, I developed SemuBot’s vision system, a social humanoid robot which is built to operate in a hospital environment. SemuBot can perform face recognition using OpenCV, gaze engagement estimation using dlib, personal identification by 128- dimensional facial embeddings through the face_recognition library, and perform emotion analysis with DeepFace. This permits the robot to effectively interact with individuals looking at the robot and optimize the interaction based on collected demographic and emotional data, thus improving real-time responsiveness. Using gaze direction detection with NumPy and dlib enables the robot to track only those looking at it, which enhances efficiency further. This helps prevent processing overload and minimizes lag in crowded settings. Focused interactions, as opposed to wide-area surveillance of all individuals in view, enhance real-time responsiveness and accuracy.
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Investigation of the Atomic Layer Deposition Principles: Effects of Growth Parameters on SiO2 Thin Films Using Hexakis(Ethylamino)disilane (AHEAD) as a Silicon Precursor
(Tartu Ülikool, 2025) Tolbin, Sergei; Jõgiaas, Taivo, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
This thesis investigates the deposition of silicon dioxide (SiO₂) thin films using Atomic Layer Deposition (ALD), with a focus on optimizing process parameters to improve film thickness, uniformity, and chemical composition. Hexakis(ethylamino)disilane (AHEAD) was used as the silicon precursor, and ozone as the oxidant. The study systematically examines the effects of growth temperature, precursor evaporation temperature, and pulse durations on film properties, with characterization performed using ellipsometry and X-ray fluorescence (XRF). This work contributes to a better understanding of the ALD process using the AHEAD precursor and provides practical guidance for tuning deposition parameters to fabricate high-quality SiO₂ films for semiconductor and nanotechnology applications.
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Experimental Setup to Measure the Rate of Oxygen Production from Cyanobacteria
(Tartu Ülikool, 2025) Kochiashvili, Elene; Islam, Quazi Saimoon, juhendaja; Kaasik, Laila, juhendaja; Pajusalu, Mihkel, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
This thesis aims to design and build an experimental setup that includes a novel oxygen sensor developed at Tartu Observatory, algae, specifically Synechococcus, for photosynthesis. This work is motivated by the need to test the oxygen sensor for future implementation in the International Space Station as well as allowing for future calibration of the sensor. The developed experimental setup incorporates control mechanisms to support the growth of Synechococcus cyanobacteria and monitor the oxygen production. The implementation and methodology of devising the required setup is discussed, highlighted key challenges and discovered solutions towards a stable experiment. The results obtained validate the functionality of the oxygen sensor over a large time period of continuous monitoring, verifying its usability in the experimental setup and laying the foundations to the eventual goal of utilizing it for future calibration of the oxygen sensor.
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Review of PF14 Analogs: Cell-Penetrating Peptides for Nucleic Acid Delivery
(Tartu Ülikool, 2025) Chuduk, Ulyana; Porosk, Ly, juhendaja; Pooga, Margus, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Effective nucleic acid based drug delivery is a key challenge in translating gene therapy to clinical practice. Cell-penetrating peptides are the promising tool for delivery of nucleic-acid-based therapeutics into the cells both in vivo and in vitro. New analogs of the well-known CPP - PepFect14 - were created by fatty acid and amino acid residue modifications with the aim of optimizing complexation of CPPs with nucleic acids, stability of CPP/siRNA complexes and efficacy of transfection in the glioblastoma cell line - U87MG. Computational methods, Luciferase expression for evaluation of transfection efficiency, complexation and stability measurements by nucleic acid intercalating dyes, dynamic light scattering analysis, zeta potential measurements and viability assays were implemented for comprehensive research of the PF14 analogs. The study revealed two PF14 analogs, that formed well-defined nanoparticles with siRNA, which were stable against degradation, efficient for siRNA transfection, and didnot impair cell viability.
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The Comparison of Three Reconstruction Methods: Straight Line, Point of the Closest Approach (POCA), Maximum Likelihood Expectation Maximization (MLEM)
(Tartu Ülikool, 2025) Abdullayev, Rufat; Zinatullin, Leonid, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Muon tomography offers an effective opportunity to image the inner parts of big and heavy objects by using cosmic ray muons. This is a comparative study that presents the performance of the three reconstruction instruments: Point of Closest Approach (POCA), Straight Line, and Maximum Likelihood Expectation-Maximization (MLEM) in muon tomography. The efficacy and accuracy of these instruments are assessed by simulating data that is the resulting effect of the GEANT4 toolkit. The setup of the simulation is close to the real experimental conditions: six virtual sensors are set above and beneath the object to pick the trajectory of the muons. The POCA technique gives the assignment of the scattering centers by computing the points of closest approach for the incoming and outgoing muons. The Straight Line technique assumes that the muon paths are 2 linear. It selects the point in the middle of the last incoming and the first outgoing points. The MLEM technique is iterative and refines an image iteratively by maximizing the likelihood of the observed data. While the POCA method and the Straight Line are methods for efficient computation, the MLEM is more accurate than they are, in particular when regarding the application in media that are this heterogeneous. It will display the pros and cons of each method and help in identifying the ideal muon tomography processes, which will cover archaeological investigations, nuclear security, and industrial inspection.
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ROS Integration for the Semubot Robot
(Tartu Ülikool, 2025) Huseynli, Omar; Raudmäe, Renno, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Humanoid robots are increasingly important in various fields like healthcare, industrial automation, and human-assistive technologies. In healthcare, humanoid robots are useful in assisting individuals with special needs, particularly children with Autism Spectrum Disorder (ASD). [1] These social robots enhance social interaction, communication skills, and learning engagement. Humanoid robots help children to develop eye contact, emotional recognition, and communication skills through structured human-robot interaction. In this thesis work, I aim to develop a Robot Operating System framework for Semubot, the first humanoid robot in Estonia.
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Impact of Archaic Introgression on the Abundance of Circulating Inflammatory Proteins in Modern Humans
(Tartu Ülikool, 2025) Rostam Nejad, Roza; Dannemann, Michael, juhendaja; Yermakovich, Danat, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Archaic introgression refers to the transfer of genetic material from archaic hominins such as Neanderthals into ancestors of modern humans. This admixture has left detectable introgressed variants in present-day human populations. Expanding studies suggest that these introgressed variants may affect the range of phenotypic traits, including immunity and inflammation. In this study, we investigated the effect of such introgressed alleles from Neanderthals on circulating inflammatory protein levels in plasma. To do so, we combined a curated archaic introgression map with genome-wide association summary statistics from protein quantitative trait loci (pQTL) studies. We identified 849 archaic SNPs that overlapped with the pQTL signals. From these, 21 archaic alleles, with the strongest association within 1Mb genomic regions, were chosen for further functional annotation. Two variants were found in regions linked to MMP10 and IL18 genes and several introgressed SNPs were associated with protein levels such as CCL25, TNF-β, CCL23, and CCL19 which are involved in autoimmune and inflammatory diseases. These findings contribute to the growing understanding of how archaic DNA continues to shape immune function in modern humans.
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Co-Expression Analysis of Sigma-1 Receptor and Tetraspanins: Insights into the Biogenesis of Sigma-1 Receptor-Enriched Extracellular Vesicles
(Tartu Ülikool, 2025) Mathur, Chaitanya; Vāvers, Edijs, juhendaja; Kopantšuk, Sergei, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Sigma-1 receptor (S1R) is a chaperone protein that resides in the endoplasmic reticulum. Recently, S1R has been associated with the generation of extracellular vesicles (EVs). Set of tetraspanins were used as markers for EVs and they were co-express with S1R in mammalian cells using MultiBacMam system. Validation of expression profiles and fluorescent intensities was performed by fluorescence spectroscopy and microscopy. Conditioned cell media was used to isolate EV particles using Tangential Flow Filtration and single-particle analysis with Total Internal Reflection Fluorescence Microscopy was performed to gain insights into the biogenesis of the S1R enriched EVs.
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Evaluation of Bacterial Viability in Photocrosslinked Hydrogels: Effects of Photoinitiator and UV Exposure on E. coli
(Tartu Ülikool, 2025) Kliaus, Dmitrii; Sarıgül, İsmail, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
The development of targeted delivery systems has significantly enhanced modern therapeutic approaches, particularly in the administration of live biotherapeutics such as probiotics. Hydrogels have emerged as effective carriers for microbial encapsulation due to their biocompatibility, customizable structures, and ability to protect living cells in challenging physiological environments. This study investigates the application of a photopolymerizable hydrogel system, incorporating a photoinitiator, to encapsulate Escherichia coli and examines bacterial viability following UV-induced crosslinking. Two experimental models were utilized: (1) a hydrogel-based encapsulation method wherein E. coli cells were mixed with a hydrogel precursor solution, shaped into pellets, and subsequently exposed to UV light at 365 nm for crosslinking; and (2) a suspension-based assay in which the cells were directly exposed to varying concentrations of photoinitiator and UV light in the absence of hydrogel, facilitating the assessment of phototoxic effects. Bacterial viability and release were quantified through time-point sampling, serial dilution, and colony-forming unit (CFU) analysis. The results indicated that both photoinitiator concentration and UV exposure significantly impact bacterial survival. Although the hydrogel encapsulation offered partial protection, elevated photoinitiator concentrations and extended UV exposure resulted in decreased CFU recovery across both experimental models. This research provide important insights into optimizing photopolymerization parameters for engineered living materials and suggest conditions under which bacterial viability can be preserved during material fabrication. The data obtained from this study can inform the design of probiotic delivery systems and bioactive hydrogel platforms for biomedical applications.
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Pilot In Vitro Study of Dexamethasone-Induced Immunomodulation in Murine Splenic T Cells
(Tartu Ülikool, 2025) Tyran, Violetta; Chinna Susan Philip; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Glucocorticoids (GCs) are key hormones in stress response and chronic elevations from chronic stress or prolonged therapeutic use accelerates immune aging and dysfunction. To dissect their direct, time- and dose-dependent effects on T cells, we established an in vitro model in which murine splenocytes were cultured with graded concentrations of dexamethasone (a potent, synthetic GC) and analyzed by 22-color spectral flow cytometry over 24, 48, and 72 hours. Dexamethasone caused a progressive, dose-dependent decline in overall viability and absolute CD4⁺/CD8⁺ T cell counts, transiently increased proliferation (Ki-67) at 48 hours before inducing collapse and apoptosis, and modulated activation (CD69, CD25) and exhaustion (PD-1) markers. Memory and naïve T cell subsets were especially vulnerable, whereas low-dose dexamethasone selectively enriched regulatory (CD4⁺Foxp3⁺) and Th1 (CD4⁺Tbet⁺) subsets. Effector cytokine production (IFN-γ, TNF-α) was markedly suppressed in a dose- and time-dependent manner. This platform thus provides a robust tool for exploring GC-driven immunosenescence, GC resistance mechanisms, and strategies to restore T cell function after chronic GC exposure.
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Brain Atrophy and Neuron Loss in the 5xFAD Mouse Model of Alzheimer's Disease
(Tartu Ülikool, 2025) Khazhmuratova, Zhanel; Hickey, Miriam Ann, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
The 5xFAD mouse model is a well-known genetic model of Alzheimer’s disease (AD) that replicates key markers of the disease in humans and is widely used in AD research. However, clear and comprehensive evidence of neurodegeneration in this model is lacking. In this study, serial stereological cryosections from female 5xFAD transgenic and wild-type littermate mice at 9 and 14 months of age were analysed using machine learning-based tools, and the structural and cellular changes were compared between genotypes. We revealed a significant reduction in striatal and cortical volumes at 9 months, followed by hippocampal volume reduction at 14 months. At 9 months, cell detection analysis revealed a significant loss of neurons in the striatum, providing, to our knowledge, the first evidence of neuronal loss in the striatum of 5xFAD mice. These changes precede the emergence of severe cognitive dysfunction in this model and align with imaging data from human AD patients showing that striatal neurodegeneration correlates with the appearance of dementia. Although the striatum is not typically the primary focus of AD research, our findings highlight its important involvement in disease progression and as a target for further research.
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SpheraSense: A Software Tool to Automate and Standardize the Analysis of Cancer Spheroid Microscopy Images
(Tartu Ülikool, 2025) Pütsepp, Margaret; Laasfeld, Tõnis, juhendaja; Lavõgina, Darja, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
In modern data-intensive biological research, making high-throughput image analysis more automated and standardized can improve key aspects of experimental work – reproducibility of results, time cost and expenses. The initiative is particularly beneficial in the research of spheroids, which simulate in vivo conditions better than the classical cell culturing model. This thesis presents SpheraSense, a software solution which introduces automation to the analysis of spheroid microscopy images, and includes the application of the software on three cancer spheroid experiments involving small cell lung cancer, head and neck cancer, and glioblastoma. SpheraSense successfully captures significant findings in experimental data, matches manual evaluation variability and reduces analysis time considerably. This thesis streamlines the analysis of spheroid experiments, contributing to more efficient and reproducible research practices.
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Identifying Microproteins with Genetic Association Data
(Tartu Ülikool, 2025) Savchak, Sviatoslav-Oleh; Alekseienko, Anastasiia, juhendaja; Abner, Erik, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
The annotation of the human genome is an ongoing process, continually refined as new functional elements are discovered. In recent years, regions previously classified as long non-coding RNAs have gained attention as many of them contain sequences that are actively translated. In this work, we mapped single-nucleotide variants (SNVs) listed in the GWAS Catalog to 7,264 previously undescribed open reading frames (ORFs) identified from the human genome. From this analysis, we identified six final microprotein encoding candidates that are likely to be associated with diseases or traits linked to their corresponding SNVs. These findings will hopefully contribute to the expanding functional annotation of the human genome and highlight the potential biological relevance of previously overlooked potential new microgenes.
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The Effect of Distant Structural Fragments on Long Lifetime Photoluminescence Properties of ARC-Lum Probes
(Tartu Ülikool, 2025) Enageli, Lizi; Enkvist, Erki, juhendaja; Viht, Kaido, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Previously discovered bisubstrate inhibitors exhibit room-temperature phosphorescence when complexed with protein kinase CK2. Such compounds can serve as valuable probes for studying protein kinases in the cell lysates and other biologically derived samples. In the present work, the effect of structural fragments distant from the phosphorescent moieties on the photoluminescence properties of the probes is investigated. Additionally, the influence of oxygen removal on photoluminescence is characterized. The findings of this work contribute to the design of novel, bright probes for CK2.
listelement.badge.access-status Open Access ,
GenePointer - A Software for Automated Identification of Resistance Markers in Bacterial Genomes
(Tartu Ülikool, 2025) Roosimaa, Aleksander; Remm, Maido, juhendaja; Aun, Erki, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Antimicrobial resistance has been a growing threat on the horizon for more than 70 years now, and recent improvements in sequencing technology and bioinformatics tools are making it easier to analyze bacterial genomes. To add upon the already existing functionality of PhenotypeSeeker, a program for phenotype prediction from genotypes, the author created the resistance marker identification pipeline, GenePointer. The program aims to identify the elements in bacterial genomes most associated with their resistance phenotypes, using mapping and alignment approaches and is made to provide insight into novel associations to make the study of resistance mechanisms faster and more efficient. The program managed to identify some of the resistance associated genes in two of the three species and antibiotic combinations analyzed. However, the current version of GenePointer did not identify any novel associations and lacks the statistical power to identify all the known resistance genes. The program in its current form is useful for analyzing and summarizing the resistance associated elements in large numbers of genomes at a time and has potential in future developments to improve on the detection of associations.
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Bismuth as a Desalination Electrode Material
(Tartu Ülikool, 2025) Agbomeji, Habeeb Olatunbosun; Grozovski, Vitali, juhendaja; Tartu Ülikool. Loodus- ja täppisteaduste valdkond; Tartu Ülikool. Bioinseneeria instituut
Addressing freshwater scarcity and the energy demands of desalination, capacitive deionization (CDI) offers an energy-efficient solution for brackish water treatment by applying low voltages (~1.2 V) to capture ions on charged electrodes. Conventional carbon-based CDI, however, is limited to low salt removal capacities (~15 mg/g). To enhance performance, hybrid-CDI with Faradaic electrodes, such as bismuth (Bi) nanopowders, is explored for high-capacity, cost-effective chloride capture, and possible desalination of the seawater. This study investigates two morphologically different Bi nanopowder electrodes in 0.1 M NaCl, revealing a sequential electrochemical mechanism - Bi to Bi₂O₃, BiOCl, and BiCl(OH)₂. Both samples exhibit near-reversible oxide formation, diffusion-controlled oxychloride production, and surface-confined hydroxylated oxychloride formation, though cathodic irreversibility poses challenges for complete film reduction. These findings highlight Bi electrodes’ potential for sustainable CDI desalination, with given morphology and purity offering significant advantages.

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