Advanced approaches in skin wound healing - a review on the multifunctional properties of MXenes in therapy and sensing.

In recent years, the use of MXenes, a class of two-dimensional materials composed of transition metal carbides, nitrides, or carbonitrides, has shown significant promise in the field of skin wound healing. This review explores the multifunctional properties of MXenes, focusing on their electrical conductivity, photothermal effects, and biocompatibility in this field. MXenes have been utilized to develop advanced wound healing devices such as hydrogels, patches, and smart bandages for healing examination. These devices offer enhanced antibacterial activity, promote tissue regeneration, and provide real-time monitoring of parameters. The review highlights the synthesis methods, chemical features, and biological effects of MXenes, emphasizing their role in innovative skin repair strategies. Additionally, it discusses the potential of MXene-based sensors for humidity, pH, and temperature monitoring, which are crucial for preventing infections and complications in wound healing. The integration of MXenes into wearable devices represents a significant advancement in wound management, promising improved clinical outcomes and enhanced quality of life for patients.

Hydrogel mechanical properties in altered gravity.

Exposure to altered gravity influences cellular behaviour in cell cultures. Hydrogels are amongst the most common materials used to produce tissue-engineering scaffolds, and their mechanical properties play a crucial role in cell-matrix interaction. However, little is known about the influence of altered gravity on hydrogel properties. Here we study the mechanical properties of Poly (ethylene glycol) diacrylate (PEGDA) and PEGDA incorporated with graphene oxide (GO) by performing tensile tests in micro and hypergravity during a Parabolic flight campaign, and by comparing them to the same tests performed in Earth gravity. We show that gravity levels do not result in a statistically significant difference in Young's modulus.

Bone Regeneration Revolution: Pulsed Electromagnetic Field Modulates Macrophage-Derived Exosomes to Attenuate Osteoclastogenesis.

Introduction: In the process of bone regeneration, a prominent role is played by macrophages involved in both the initial inflammation and the regeneration/vascularization phases, due to their M2 anti-inflammatory phenotype. Together with osteoclasts, they participate in the degradation of the bone matrix if the inflammatory process does not end. In this complex scenario, recently, much attention has been paid to extracellular communication mediated by nanometer-sized vesicles, with high information content, called exosomes (EVs). Considering these considerations, the purpose of the present work is to demonstrate how the presence of a pulsed electromagnetic field (PEMF) can positively affect communication through EVs. Methods: To this aim, macrophages and osteoclasts were treated in vitro with PEMF and analyzed through molecular biology analysis and by electron microscopy. Moreover, EVs produced by macrophages were characterized and used to verify their activity onto osteoclasts. Results: The results confirmed that PEMF not only reduces the inflammatory activity of macrophages and the degradative activity of osteoclasts but that the EVS produced by macrophages, obtained from PEMF treatment, positively affect osteoclasts by reducing their activity. Discussion: The co-treatment of PEMF with M2 macrophage-derived EVs (M2-EVs) decreased osteoclastogenesis to a greater degree than separate treatments.

Adipose-derived stem cell exosomes act as delivery vehicles of microRNAs in a dog model of chronic hepatitis.

Exosomes are nanosized extracellular vesicles secreted by all cell types, including canine adipose-derived stem cells (cADSCs). By mediating intercellular communication, exosomes modulate the biology of adjacent and distant cells by transferring their cargo. In the present work after isolation and characterization of exosomes derived from canine adipose tissue, we treated the same canine donors affected by hepatopathies with the previously isolated exosomes. We hypothesize that cADSC-sourced miRNAs are among the factors responsible for a regenerative and anti-inflammatory effect in the treatment of hepatopathies in dogs, providing the clinical veterinary field with an effective and innovative cell-free therapy. Exosomes were isolated and characterized for size, distribution, surface markers, and for their miRNomic cargo by microRNA sequencing. 295 dogs affected with hepatopathies were treated and followed up for 6 months to keep track of their biochemical marker levels. Results confirmed that exosomes derived from cADSCs exhibited an average diameter of 91 nm, and positivity to 8 known exosome markers. The administration of exosomes to dogs affected by liver-associated inflammatory pathologies resulted in the recovery of the animal alongside the normalization of biochemical parameters of kidney function. In conclusion, cADSCs-derived exosomes are a promising therapeutic tool for treating inflammatory disorders in animal companions.

Small Warriors of Nature: Novel Red Emissive Chlorophyllin Carbon Dots Harnessing Fenton-Fueled Ferroptosis for In Vitro and In Vivo Cancer Treatment.

The appeal of carbon dots (CDs) has grown recently, due to their established biocompatibility, adjustable photoluminescence properties, and excellent water solubility. For the first time in the literature, copper chlorophyllin-based carbon dots (Chl-D CDs) are successfully synthesized. Chl-D CDs exhibit unique spectroscopic traits and are found to induce a Fenton-like reaction, augmenting photodynamic therapy (PDT) efficacies via ferroptotic and apoptotic pathways. To bolster the therapeutic impact of Chl-D CDs, a widely used cancer drug, temozolomide, is linked to their surface, yielding a synergistic effect with PDT and chemotherapy. Chl-D CDs' biocompatibility in immune cells and in vivo models showed great clinical potential.Proteomic analysis was conducted to understand Chl-D CDs' underlying cancer treatment mechanism. The study underscores the role of reactive oxygen species formation and pointed toward various oxidative stress modulators like aldolase A (ALDOA), aldolase C (ALDOC), aldehyde dehydrogenase 1B1 (ALDH1B1), transaldolase 1 (TALDO1), and transketolase (TKT), offering a deeper understanding of the Chl-D CDs' anticancer activity. Notably, the Chl-D CDs' capacity to trigger a Fenton-like reaction leads to enhanced PDT efficiencies through ferroptotic and apoptotic pathways. Hence, it is firmly believed that the inherent attributes of Chl-CDs can lead to a secure and efficient combined cancer therapy.

Synergized photothermal therapy and magnetic field induced hyperthermia via bismuthene for lung cancer combinatorial treatment.

Thanks to its intrinsic properties, two-dimensional (2D) bismuth (bismuthene) can serve as a multimodal nanotherapeutic agent for lung cancer acting through multiple mechanisms, including photothermal therapy (PTT), magnetic field-induced hyperthermia (MH), immunogenic cell death (ICD), and ferroptosis. To investigate this possibility, we synthesized bismuthene from the exfoliation of 3D layered bismuth, prepared through a facile method that we developed involving surfactant-assisted chemical reduction, with a specific focus on improving its magnetic properties. The bismuthene nanosheets showed high in vitro and in vivo anti-cancer activity after simultaneous light and magnetic field exposure in lung adenocarcinoma cells. Only when light and magnetic field are applied together, we can achieve the highest anti-cancer activity compared to the single treatment groups. We have further shown that ICD-dependent mechanisms were involved during this combinatorial treatment strategy. Beyond ICD, bismuthene-based PTT and MH also resulted in an increase in ferroptosis mechanisms both in vitro and in vivo, in addition to apoptotic pathways. Finally, hemolysis in human whole blood and a wide variety of assays in human peripheral blood mononuclear cells indicated that the bismuthene nanosheets were biocompatible and did not alter immune function. These results showed that bismuthene has the potential to serve as a biocompatible platform that can arm multiple therapeutic approaches against lung cancer.

Exploiting Mass Spectrometry to Unlock the Mechanism of Nanoparticle-Induced Inflammasome Activation.

Nanoparticles (NPs) elicit sterile inflammation, but the underlying signaling pathways are poorly understood. Here, we report that human monocytes are particularly vulnerable to amorphous silica NPs, as evidenced by single-cell-based analysis of peripheral blood mononuclear cells using cytometry by time-of-flight (CyToF), while silane modification of the NPs mitigated their toxicity. Using human THP-1 cells as a model, we observed cellular internalization of silica NPs by nanoscale secondary ion mass spectrometry (nanoSIMS) and this was confirmed by transmission electron microscopy. Lipid droplet accumulation was also noted in the exposed cells. Furthermore, time-of-flight secondary ion mass spectrometry (ToF-SIMS) revealed specific changes in plasma membrane lipids, including phosphatidylcholine (PC) in silica NP-exposed cells, and subsequent studies suggested that lysophosphatidylcholine (LPC) acts as a cell autonomous signal for inflammasome activation in the absence of priming with a microbial ligand. Moreover, we found that silica NPs elicited NLRP3 inflammasome activation in monocytes, whereas cell death transpired through a non-apoptotic, lipid peroxidation-dependent mechanism. Together, these data further our understanding of the mechanism of sterile inflammation.

V4 C3 MXene Immune Profiling and Modulation of T Cell-Dendritic Cell Function and Interaction.

Although vanadium-based metallodrugs are recently explored for their effective anti-inflammatory activity, they frequently cause undesired side effects. Among 2D nanomaterials, transition metal carbides (MXenes) have received substantial attention for their promise as biomedical platforms. It is hypothesized that vanadium immune properties can be extended to MXene compounds. Therefore, vanadium carbide MXene (V4 C3 ) is synthetized, evaluating its biocompatibility and intrinsic immunomodulatory effects. By combining multiple experimental approaches in vitro and ex vivo on human primary immune cells, MXene effects on hemolysis, apoptosis, necrosis, activation, and cytokine production are investigated. Furthermore, V4 C3 ability is demonstrated to inhibit T cell-dendritic cell interactions, evaluating the modulation of CD40-CD40 ligand interaction, two key costimulatory molecules for immune activation. The material biocompatibility at the single-cell level on 17 human immune cell subpopulations by single-cell mass cytometry is confirmed. Finally, the molecular mechanism underlying V4 C3 immune modulation is explored, demonstrating a MXene-mediated downregulation of antigen presentation-associated genes in primary human immune cells. The findings set the basis for further V4 C3 investigation and application as a negative modulator of the immune response in inflammatory and autoimmune diseases.

Low Dose of Ti3 C2 MXene Quantum Dots Mitigate SARS-CoV-2 Infection.

MXene QDs (MQDs) have been effectively used in several fields of biomedical research. Considering the role of hyperactivation of immune system in infectious diseases, especially in COVID-19, MQDs stand as a potential candidate as a nanotherapeutic against viral infections. However, the efficacy of MQDs against SARS-CoV-2 infection has not been tested yet. In this study, Ti3 C2 MQDs are synthesized and their potential in mitigating SARS-CoV-2 infection is investigated.  Physicochemical characterization suggests that MQDs are enriched with abundance of bioactive functional groups such as oxygen, hydrogen, fluorine, and chlorine groups as well as surface titanium oxides. The efficacy of MQDs is tested in VeroE6 cells infected with SARS-CoV-2. These data demonstrate that the treatment with MQDs is able to mitigate multiplication of virus particles, only at very low doses such as 0,15 µg mL-1 . Furthermore, to understand the mechanisms of MQD-mediated anti-COVID properties, global proteomics analysis are performed and determined differentially expressed proteins between MQD-treated and untreated cells. Data reveal that MQDs interfere with the viral life cycle through different mechanisms including the Ca2 + signaling pathway, IFN-α response, virus internalization, replication, and translation. These findings suggest that MQDs can be employed to develop future immunoengineering-based nanotherapeutics strategies against SARS-CoV-2 and other viral infections.

Immune Profiling and Multiplexed Label-Free Detection of 2D MXenes by Mass Cytometry and High-Dimensional Imaging.

There is a critical unmet need to detect and image 2D materials within single cells and tissues while surveying a high degree of information from single cells. Here, a versatile multiplexed label-free single-cell detection strategy is proposed based on single-cell mass cytometry by time-of-flight (CyTOF) and ion-beam imaging by time-of-flight (MIBI-TOF). This strategy, "Label-free sINgle-cell tracKing of 2D matErials by mass cytometry and MIBI-TOF Design" (LINKED), enables nanomaterial detection and simultaneous measurement of multiple cell and tissue features. As a proof of concept, a set of 2D materials, transition metal carbides, nitrides, and carbonitrides (MXenes), is selected to ensure mass detection within the cytometry range while avoiding overlap with more than 70 currently available tags, each able to survey multiple biological parameters. First, their detection and quantification in 15 primary human immune cell subpopulations are demonstrated. Together with the detection, mass cytometry is used to capture several biological aspects of MXenes, such as their biocompatibility and cytokine production after their uptake. Through enzymatic labeling, MXenes' mediation of cell-cell interactions is simultaneously evaluated. In vivo biodistribution experiments using a mixture of MXenes in mice confirm the versatility of the detection strategy and reveal MXene accumulation in the liver, blood, spleen, lungs, and relative immune cell subtypes. Finally, MIBI-TOF is applied to detect MXenes in different organs revealing their spatial distribution. The label-free detection of 2D materials by mass cytometry at the single-cell level, on multiple cell subpopulations and in multiple organs simultaneously, will enable exciting new opportunities in biomedicine.

2D Materials for Cardiac Tissue Repair and Regeneration.

Cardiovascular diseases (CVDs) have a massive impact on human health. Due to the limited regeneration capacity of adult heart tissue, CVDs are the leading cause of death and disability worldwide. Even though there are surgical and pharmacological treatments for CVDs, regenerative strategies are the most promising approaches and have the potential to benefit millions of people. As in any other tissue engineering approach, the repair and regeneration of damaged cardiac tissues generally involve scaffolds made up of biodegradable and biocompatible materials, cellular components such as stem cells, and growth factors. This review provides an overview of biomaterial-based tissue engineering approaches for CVDs with a specific focus on the potential of 2D materials. It is essential to consider both physicochemical and immunomodulatory properties for evaluating the applicability of 2D materials in cardiac tissue repair and regeneration. As new members of the 2D materials will be explored, they will quickly become part of cardiac tissue engineering technologies.

Graphene oxide activates B cells with upregulation of granzyme B expression: evidence at the single-cell level for its immune-modulatory properties and anticancer activity.

We recently found by single-cell mass cytometry that ex vivo human B cells internalize graphene oxide (GO). The functional impact of such uptake on B cells remains unexplored. Here, we disclosed the effects of GO and amino-functionalized GO (GONH2) interacting with human B cells in vitro and ex vivo at the protein and gene expression levels. Moreover, our study considered three different subpopulations of B cells and their functionality in terms of: (i) cytokine production, (ii) activation markers, (iii) killing activity towards cancer cells. Single-cell mass cytometry screening revealed the higher impact of GO on cell viability towards naïve, memory, and plasma B cell subsets. Different cytokines such as granzyme B (GrB) and activation markers, like CD69, CD80, CD138, and CD38, were differently regulated by GONH2 compared to GO, supporting possible diverse B cell activation paths. Moreover, co-culture experiments also suggest the functional ability of both GOs to activate B cells and therefore enhance the toxicity towards HeLa cancer cell line. Complete transcriptomic analysis on a B cell line highlighted the distinctive GO and GONH2 elicited responses, inducing pathways such as B cell receptor and CD40 signaling pathways, key players for GrB secretion. B cells were regularly left behind the scenes in graphene biological studies; our results may open new horizons in the development of GO-based immune-modulatory strategies having B cell as main actors.

Graphene Oxide Nanosheets Interact and Interfere with SARS-CoV-2 Surface Proteins and Cell Receptors to Inhibit Infectivity.

Nanotechnology can offer a number of options against coronavirus disease 2019 (COVID-19) acting both extracellularly and intracellularly to the host cells. Here, the aim is to explore graphene oxide (GO), the most studied 2D nanomaterial in biomedical applications, as a nanoscale platform for interaction with SARS-CoV-2. Molecular docking analyses of GO sheets on interaction with three different structures: SARS-CoV-2 viral spike (open state - 6VYB or closed state - 6VXX), ACE2 (1R42), and the ACE2-bound spike complex (6M0J) are performed. GO shows high affinity for the surface of all three structures (6M0J, 6VYB and 6VXX). When binding affinities and involved bonding types are compared, GO interacts more strongly with the spike or ACE2, compared to 6M0J. Infection experiments using infectious viral particles from four different clades as classified by Global Initiative on Sharing all Influenza Data (GISAID), are performed for validation purposes. Thin, biological-grade GO nanoscale (few hundred nanometers in lateral dimension) sheets are able to significantly reduce copies for three different viral clades. This data has demonstrated that GO sheets have the capacity to interact with SARS-CoV-2 surface components and disrupt infectivity even in the presence of any mutations on the viral spike. GO nanosheets are proposed to be further explored as a nanoscale platform for development of antiviral strategies against COVID-19.

2D MXenes with antiviral and immunomodulatory properties: A pilot study against SARS-CoV-2.

Two-dimensional transition metal carbides/carbonitrides known as MXenes are rapidly growing as multimodal nanoplatforms in biomedicine. Here, taking SARS-CoV-2 as a model, we explored the antiviral properties and immune-profile of a large panel of four highly stable and well-characterized MXenes - Ti3C2Tx, Ta4C3T x , Mo2Ti2C3T x and Nb4C3T x . To start with antiviral assessment, we first selected and deeply analyzed four different SARS-CoV-2 genotypes, common in most countries and carrying the wild type or mutated spike protein. When inhibition of the viral infection was tested in vitro with four viral clades, Ti3C2T x in particular, was able to significantly reduce infection only in SARS-CoV-2/clade GR infected Vero E6 cells. This difference in the antiviral activity, among the four viral particles tested, highlights the importance of considering the viral genotypes and mutations while testing antiviral activity of potential drugs and nanomaterials. Among the other MXenes tested, Mo2Ti2C3T x also showed antiviral properties. Proteomic, functional annotation analysis and comparison to the already published SARS-CoV-2 protein interaction map revealed that MXene-treatment exerts specific inhibitory mechanisms. Envisaging future antiviral MXene-based drug nano-formulations and considering the central importance of the immune response to viral infections, the immune impact of MXenes was evaluated on human primary immune cells by flow cytometry and single-cell mass cytometry on 17 distinct immune subpopulations. Moreover, 40 secreted cytokines were analyzed by Luminex technology. MXene immune profiling revealed i) the excellent bio and immune compatibility of the material, as well as the ability of MXene ii) to inhibit monocytes and iii) to reduce the release of pro-inflammatory cytokines, suggesting an anti-inflammatory effect elicited by MXene. We here report a selection of MXenes and viral SARS-CoV-2 genotypes/mutations, a series of the computational, structural and molecular data depicting deeply the SARS-CoV-2 mechanism of inhibition, as well as high dimensional single-cell immune-MXene profiling. Taken together, our results provide a compendium of knowledge for new developments of MXene-based multi-functioning nanosystems as antivirals and immune-modulators.

Osteogenic Properties of 3D-Printed Silica-Carbon-Calcite Composite Scaffolds: Novel Approach for Personalized Bone Tissue Regeneration.

Carbon enriched bioceramic (C-Bio) scaffolds have recently shown exceptional results in terms of their biological and mechanical properties. The present study aims at assessing the ability of the C-Bio scaffolds to affect the commitment of canine adipose-derived mesenchymal stem cells (cAD-MSCs) and investigating the influence of carbon on cell proliferation and osteogenic differentiation of cAD-MSCs in vitro. The commitment of cAD-MSCs to an osteoblastic phenotype has been evaluated by expression of several osteogenic markers using real-time PCR. Biocompatibility analyses through 3-(4,5-dimethyl- thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), lactate dehydrogenase (LDH) activity, hemolysis assay, and Ames test demonstrated excellent biocompatibility of both materials. A significant increase in the extracellular alkaline phosphatase (ALP) activity and expression of runt-related transcription factor (RUNX), ALP, osterix (OSX), and receptor activator of nuclear factor kappa-Β ligand (RANKL) genes was observed in C-Bio scaffolds compared to those without carbon (Bio). Scanning electron microscopy (SEM) demonstrated excellent cell attachment on both material surfaces; however, the cellular layer on C-Bio fibers exhibited an apparent secretome activity. Based on our findings, graphene can improve cell adhesion, growth, and osteogenic differentiation of cAD-MSCs in vitro. This study proposed carbon as an additive for a novel three-dimensional (3D)-printable biocompatible scaffold which could become the key structural material for bone tissue reconstruction.

Lateral dimension and amino-functionalization on the balance to assess the single-cell toxicity of graphene on fifteen immune cell types.

Given the wide variety of potential applications of graphene oxide (GO), its consequent release into the environment poses serious concerns on its safety. The future production and exploitation of graphene in the years to come should be guided by its specific chemical-physical characteristics. The unparalleled potential of single-cell mass cytometry (CyTOF) to dissect by high-dimensionality the specific immunological effects of nanomaterials, represents a turning point in nanotoxicology. It helps us to identify the safe graphene in terms of physical-chemical properties and therefore to direct its future safe production. Here we present a high-dimensional study to evaluate two historically indicated as key parameters for the safe exploitation: functionalization and dimension. The role of lateral dimension and the amino-functionalization of GO on their immune impact were here evaluated as synergistic players. To this end, we dissected the effects of GO, characterized by a large or small lateral size (GO 1.32 µm and GO 0.13 µm, respectively), and its amino-functionalized counterpart (GONH2 1.32 µm and GONH2 0.13 µm, respectively) on fifteen cell types of human primary peripheral blood mononuclear cells (PBMCs). We describe how the smallest later size not only evokes pronounced toxicity on the pool of PBMCs compared to larger GOs but also towards the distinct immune cell subpopulations, in particular on non-classical monocytes, plasmacytoid dendritic cells (pDCs), natural killer cells (NKs) and B cells. The amino-functionalization was able to improve the biocompatibility of classical and non-classical monocytes, pDCs, NKs, and B cells. Detailed single-cell analysis further revealed a complex interaction of all GOs with the immune cells, and in particular monocyte subpopulations, with different potency depending on their physicochemical properties. Overall, by high-dimensional profiling, our study demonstrates that the lateral dimension is an important factor modulating immune cells and specifically monocyte activation, but a proper surface functionalization is the dominant characteristic in its immune effects. In particular, the amino-functionalization can critically modify graphene impact dampening the immune cell activation. Our study can serve as a guide for the future broad production and use of graphene in our everyday life.

Bioinspired Scaffold Action Under the Extreme Physiological Conditions of Simulated Space Flights: Osteogenesis Enhancing Under Microgravity.

Prolonged exposure to microgravity (MG) during long-duration space flights is known to induce severe dysregulation of osteoblast functions connected to a significant bone loss, similar to the condition induced by osteoporosis. Hence, we here present MG as a promising model to challenge the effectiveness of new scaffolds designed for bone regeneration in counteracting bone loss. To this end, we carried out an integrative study aimed to evaluate, in the extreme condition of Random Positioning Machine-simulated MG, the osteoinductive potential of nanocrystalline magnesium-doped hydroxyapatite/type I collagen composite scaffold (MHA/Coll), that we previously demonstrated to be an excellent tool for bone tissue engineering. Initially, to test the osteoinductive properties of our bioinspired-scaffold, MHA/Coll structure was fully characterized under MG condition and compared to its static counterpart. Human bone marrow-derived mesenchymal stem cells were used to investigate the scaffold biocompatibility and ability to promote osteogenic differentiation after long-duration exposure to MG (up to 21 days). The results demonstrate that the nanostructure of MHA/Coll scaffold can alleviate MG-induced osteoblast dysfunction, promoting cell differentiation along the osteogenic lineage, with a consequent reduction in the expression of the surface markers CD29, CD44, and CD90. Moreover, these findings were corroborated by the ability of MHA/Coll to induce the expression of genes linked to osteogenesis, including alkaline phosphatase and osteocalcin. This study confirmed MHA/Coll capabilities in promoting osteogenesis even in extreme long-term condition of MG, suggesting MG as an effective challenging model to apply in future studies to validate the ability of advanced scaffolds to counteract bone loss, facilitating their application in translational Regenerative Medicine and Tissue Engineering.

Nanocytometer for smart analysis of peripheral blood and acute myeloid leukemia: a pilot study.

We realize an ultracompact nanocytometer for real-time impedimetric detection and classification of subpopulations of living cells. Nanoscopic nanowires in a microfluidic channel act as nanocapacitors and measure in real time the change of the amplitude and phase of the output voltage and, thus, the electrical properties of living cells. We perform the cell classification in the human peripheral blood (PBMC) and demonstrate for the first time the possibility to discriminate monocytes and subpopulations of lymphocytes in a label-free format. Further, we demonstrate that the PBMC of acute myeloid leukemia and healthy samples grant the label free identification of the disease. Using the algorithm based on machine learning, we generated specific data patterns to discriminate healthy donors and leukemia patients. Such a solution has the potential to improve the traditional diagnostics approaches with respect to the overall cost and time effort, in a label-free format, and restrictions of the complex data analysis.

Degradation of Structurally Defined Graphene Nanoribbons by Myeloperoxidase and the Photo-Fenton Reaction.

As an emerging member of the graphene family, structurally defined graphene nanoribbons (GNRs) have shown promising applications in various fields. The evaluation of the degradability of GNRs is particularly important for assessing the persistence level and risk of these materials in living organisms and the environment. However, there is a void in the study of the degradation of GNRs. Here, we report the degradation behavior of GNRs in the presence of human myeloperoxidase (hMPO) or treated with the photo-Fenton (PF) reaction. With the assistance of potassium hydroxide or imidazole, which facilitates the dispersion of GNRs in the aqueous solution, GNRs underwent only partial degradation after 25-hour incubation with hMPO, while, the PF reaction degraded GNRs almost completely after 120 hours. These results indicate that structurally precise GNRs can be efficiently degraded under suitable conditions, providing more opportunities for future applications in different fields.