1. In vitro toxicity assessment of graphene quantum dots using a 3D HepG2 modelIrma Durmišević, Anja Haverić, Sonja Žabkar, Alja Štern, Katja Kološa, Petra Jenuš, Iza Rozman, Bojana Žegura, 2026, original scientific article Abstract: In the present study, two types of graphene quantum dots (GQDs) were investigated: green-emitting (G-GQDs) and blue-emitting (B-GQDs). Physicochemical characterisation was performed using transmission electron microscopy (TEM), zeta potential, and hydrodynamic radius measurements to evaluate the morphology, particle size, aggregation behaviour, and colloidal stability of the GQDs in both water and cell culture medium. G-GQDs exhibited superior colloidal stability and more uniform dispersion than B-GQDs, whereas both types showed reduced aggregation and surface charge in cell culture medium due to protein corona formation. Toxicological characterisation was performed using an in vitro human hepatocellular carcinoma (HepG2) 3D spheroid model, with GQDs exposures up to 250 µg/mL (100 µg/cm2). Cytotoxicity was measured using the CellTiter-Glo luminometric assay, while genotoxicity was evaluated by the comet assay and flow cytometric analysis of γH2AX and phosphorylated histone H3 (p-H3) after 24 h of exposure. Both GQDs induced dose-dependent cytotoxic effects in HepG2 spheroids. At non-cytotoxic concentrations, a dose-dependent increase in DNA damage was observed, as determined by the comet assay. However, no evidence of DNA double-strand breaks (γH2AX) or elevated p-H3 levels was detected, suggesting the absence of clastogenic and aneugenic activity. The observed DNA single-strand breaks may be partly attributed to reactive oxygen species induction. These results indicate that, although GQDs induced cytotoxicity and single-strand DNA damage, no clear evidence of more severe genotoxic effects was observed under the tested conditions. Further studies are warranted to elucidate underlying mechanisms and comprehensively assess the safety profile of GQDs for biomedical applications.
Keywords: nanomaterials, graphene quantum dots, HepG2 spheroids, toxicity
Published in DiRROS: 19.03.2026; Views: 254; Downloads: 79
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2. Detection of specific antibodies against SARS-CoV-2 spike protein via ultra-sensitive bio-functionalized carbonnitride-reduced graphene oxide electrochemical immunosensing platform in real samplesMohd. Abubakar Sadique, Shalu Yadav, Pushpesh Ranjan, Raghuraj S. Chouhan, Ivan Jerman, Ashok Kumar, Saurabh Saigal, Sagar Khadanga, Raju Khan, Avanish K. Srivastava, 2023, original scientific article Abstract: In this work, we fabricate a facile de novo synthesis route to prepare bio-functionalized carbon nitride-reduced graphene oxide with chitosan (Chi) nanocomposite (C3N4/RGO/Chi). The nitrogen-rich C3N4 has been synthesized through facile and low-cost thermal oxidation and offers a metal-free and highly active surface for synergistic modification with RGO and Chi. Moreover, the synergistically incorporated C3N4/RGO and biopolymer improve the electrocatalytic activity, provide surface functionalities, and enhance electroconductivity for immunosensing applications. Consequently, the bio-functionalized C3N4/RGO nanocomposite provides a suitable substrate for the immobilization of SARS-CoV-2 RBD spike protein. The immunosensor detects SARS-CoV-2 antibodies in a wide detection range from 10 zg mL−1 (10 × 10−21 g mL−1) to 100 ng mL−1 with an ultra-low detection limit (LOD) of 3.31 zg mL−1. The validation of the immunosensor was also carried out on spiked serum samples, which show a linear detection range of 100 ag mL−1 to 100 ng mL−1 and a LOD of 1.73 ag mL−1. Nevertheless, the clinical diagnostic application of the immunosensor is validated through the examination of real serum samples from COVID-19 patients. The results suggest that the immunosensor can be efficiently used as a screening platform to distinguish between positive and negative samples with high accuracy. The findings of the work have the potential to translate the immunosensing strategy into next-generation point-of-care testing (POCT) of various infectious diseases.
Keywords: SARS-CoV-2, detection, nanomaterials
Published in DiRROS: 16.12.2025; Views: 346; Downloads: 204
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3. Emerging trends and recent progress of MXene as a promising 2D material for point of care (POC) diagnosticsRaghuraj S. Chouhan, Maitri Shah, Drishya Prakashan, P.R. Ramya, Pratik Kolhe, Sonu Gandhi, 2023, review article Abstract: Two-dimensional (2D) nanomaterials with chemical and structural diversity have piqued the interest of the scientific community due to their superior photonic, mechanical, electrical, magnetic, and catalytic capabilities that distinguish them from their bulk counterparts. Among these 2D materials, two-dimensional (2D) transition metal carbides, carbonitrides, and nitrides with a general chemical formula of Mn+1XnTx (where n = 1–3), together known as MXenes, have gained tremendous popularity and demonstrated competitive performance in biosensing applications. In this review, we focus on the cutting-edge advances in MXene-related biomaterials, with a systematic summary on their design, synthesis, surface engineering approaches, unique properties, and biological properties. We particularly emphasize the property–activity–effect relationship of MXenes at the nano– bio interface. We also discuss the recent trends in the application of MXenes in accelerating the performance of conventional point of care (POC) devices towards more practical approaches as the next generation of POC tools. Finally, we explore in depth the existing problems, challenges, and potential for future improvement of MXene-based materials for POC testing, with the goal of facilitating their early realization of biological applications.
Keywords: MXenes, 2D nanomaterials, biosensors, POC testing
Published in DiRROS: 16.12.2025; Views: 418; Downloads: 251
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4. Nanovaccines to combat drug resistance : the next-generation immunisationK. Manju, S. Niranjan Raj, Raghuraj S. Chouhan, Syed Baker, 2023, review article Abstract: Background. The present review envisages the role of nanovaccines to combat the global challenges of antimicrobial resistance. Nanovaccines are a novel formulation comprised of nanomaterials coupled with an immunogenic component to elicit the immune response and provide protection against the desired infectious disease. The nanovaccines with unique physicochemical properties can be more efficient against targeting the desired tissues in the body, aids in prolong circulation to promote antigen-presenting cells to act upon the target antigens. Main content. The present review envisages the development of nanovaccines against antimicrobial-resistant pathogens. The use of nanovaccines can exhibit potent antigenicity with prolonged retention and controlled release to induce both cell- and antibody-mediated responses. Nanovaccines usage is still in the early stages and can be next-generation immunisation for prophylactic and therapeutic efficiency. The future development of nanovaccines against multi-drug-resistant pathogens can explore new avenues. Based on these facts, the present review is designed from the previously reported scientific studies and compiled with the fact that nanovaccines can revolutionise vaccine strategies. The articles were extracted from reputed databases like PubMed, Scopus, and ESCI. The size and conjugating chemistry of nanomaterials can be beneficial in developing novel multi-nanovaccine formulations that can target pools of antimicrobial resistance mechanisms. Conclusion. Overall, the nanovaccines can form one of the best effective modes of targeting multi-drug-resistant pathogens. The nanovaccines can stimulate the innate immune response and generate effective immune-therapeutic novel formulation against infectious pathogens. Based on these facts and considerations, the present article makes an alarming call to develop nanovaccines to counter multi-drug resistance.
Keywords: nanovaccines, antimicrobial drug resistance, nanomaterials, HIV, WHO
Published in DiRROS: 16.12.2025; Views: 429; Downloads: 236
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5. Common gene expression patterns in environmental model organisms exposed to engineered nanomaterials : a meta-analysisMichael Burkard, Alexander Betz, Kristin Schirmer, Anže Županič, 2020, original scientific article Abstract: The use of omics is gaining importance in the field of nanoecotoxicology; an increasing number of studies are aiming to investigate the effects and modes of action of engineered nanomaterials (ENMs) in this way. However, a systematic synthesis of the outcome of such studies regarding common responses and toxicity pathways is currently lacking. We developed an R-scripted computational pipeline to perform reanalysis and functional analysis of relevant transcriptomic data sets using a common approach, independent from the ENM type, and across different organisms, including Arabidopsis thaliana, Caenorhabditis elegans, and Danio rerio. Using the pipeline that can semiautomatically process data from different microarray technologies, we were able to determine the most common molecular mechanisms of nanotoxicity across extremely variable data sets. As expected, we found known mechanisms, such as interference with energy generation, oxidative stress, disruption of DNA synthesis, and activation of DNA-repair but also discovered that some less-described molecular responses to ENMs, such as DNA/RNA methylation, protein folding, and interference with neurological functions, are present across the different studies. Results were visualized in radar charts to assess toxicological response patterns allowing the comparison of different organisms and ENM types. This can be helpful to retrieve ENM-related hazard information and thus fill knowledge gaps in a comprehensive way in regard to the molecular underpinnings and mechanistic understanding of nanotoxicity.
Keywords: gene expression, nanomaterials
Published in DiRROS: 19.07.2024; Views: 1105; Downloads: 746
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