Pollution with neurotoxic heavy metals is a global issue and increasingly problematic for environment and health worldwide. Development of efficient sorbents for in vivo detoxication, which are biocompatible, is of urgent necessity. Here, series of biochars for adsorption of heavy metals was prepared using “green” principles from agricultural waste corn cobs (CB) and dry apples (AB) by pyrolysis without additional functionalization. Neurotoxicity risk of CB and AB was assessed using cortex nerve terminals (synaptosomes), which are a sensitive biomodel with a rapid response to changes in key K+/Na+/Ca2+-dependent synaptic characteristics and membrane integrity. Sorption capacity of CB and AB was compared in aquatic media and animal model. In synaptosomes, biochars themselves did not affect the extrasynaptosomal levels of excitatory and inhibitory neurotransmitters L-[3H]glutamate and [3H]GABA, respectively, and the mitochondrial membrane potential. Therefore, CB and AB were biocompatible without neurotoxic signs. All studied biochars adsorbed Cu2+ in synaptosomal suspension. However, CB was more efficient regarding adsorption of Cu2+, as compared to AB. CB completely abolished (by 98 %) Cu2+-induced increase in the extrasynaptosomal levels of L-[3H]glutamate and [3H]GABA. Both biochars had fewer efficacies in mitigation of toxic effect of Hg2+, Cd2+ and Pb2+ in nerve terminals as compared to Cu2+ one. Detoxication radiolabeled data were confirmed by fluorimetry measuring the plasma membrane/mitochondrial membrane potential, and ROS generation using dyes rhodamine 6G, JC-1, DCF, respectively. CB due to its unique ability to completely eliminate harmful Cu2+-induced effects in nerve terminal model may be further considered as non-toxic de-coopering agent in Cu2+- targeted therapy.

Xenobiotic and trace heavy metals such as Pb2+, Cd2+ and Cu2+, which abundantly pollute the environment, are hazardous neurotoxicants. Herein, the ability of "green" carbon dots from coffee waste (CCDs) to adsorb Pb2+, Cd2+ and Cu2+ in aquatic media and in biological systems, such as presynaptic rat cortex nerve terminals, was assessed. Using ICP-MS and DLS, it was demonstrated that CCDs were able to adsorb Pb2+, Cd2+ and Cu2+ in water, forming complexes with these metals. In animal experiments, CCDs, even at a high concentration of 2 mg ml-1, did not change the extracellular levels of the excitatory neurotransmitter l-[14C]glutamate and inhibitory one [3H]GABA in nerve terminal preparations, and so, CCDs are highly biocompatible. Combined application of CCDs with Pb2+, Cd2+ and Cu2+ resulted in a significant mitigation of the acute Pb2+/Cd2+/Cu2+-induced increase in the extracellular levels of l-[14C]glutamate and [3H]GABA in nerve terminal preparations. Therefore, CCDs did not possess neurotoxic effects and, due to their original synthesis methodology, were able to adsorb Pb2+, Cd2+ and Cu2+ in aquatic media and in biological systems, mitigating acute Pb2+/Cd2+/Cu2+-induced neurotoxicity in nerve terminals. CCDs have prophylactic and therapeutic potential to combat heavy metal poisoning. This study fits several key priorities in environmental science as a heavy metal adsorbent obtained from biowaste using an eco-friendly synthesis protocol has the potential to combat heavy metal poisoning in organisms and wastewater.

Trace metal Cu and carbonaceous airborn particulate matter (PM) are dangerous neuropollutants. Here, the ability of Cu2+ to modulate the neurotoxicity caused by water-suspended wood smoke PM preparations (SPs) and vice versa was examined using presynaptic rat cortex nerve terminals. Interaction of Cu2+ and SPs, changes of particle size and surface properties were shown in the presence of Cu2+ using microscopy, DLS, and IR spectroscopy. In nerve terminals, Cu2+ and SPs per se elevated the ambient levels of excitatory and inhibitory neurotransmitters L-[14C]glutamate and [3H]GABA, respectively. During combined application, Cu2+ significantly enhanced a SPs-induced increase in the ambient levels of both neurotransmitters, thereby demonstrating a cumulative synergistic effect and significant interference in the neurotoxic threat associated with Cu2+and SPs. In fluorimetric measurements, Cu2+ and SPs also demonstrated cumulative synergistic effects on the membrane potential, mitochondrial potential, synaptic vesicle acidification and ROS generation. Therefore, synergistic effects of Cu2+ and SPs on the most crucial presynaptic characteristics and neurohazard of multiple pollutants through excitatory/inhibitory imbalance, disruption of the membrane and mitochondrial potential, vesicle acidification and ROS generation were revealed. Increased expansion and burden of neuropathology may result from underestimation of synergistic interference of the neurotoxic effects of Cu2+ and carbonaceous smoke PM.

Aim. In biomedical applications, silica nanoparticles are promising for controlled drug delivery. Also, from an environmental point of view, silica accounts for the most significant part of the mass of air pollution, particularly matter components, especially during sand dust storms. Methods. Amino-grafted mesoporous silica nanoparticles (MSN-NH2) were synthesized by means of co-condensation of tetraethoxysilane and 3-aminopropyltriethoxysilane and characterized using TEM, IR-spectroscopy, and powder X-ray diffraction. Neuromodulatory and related properties of MSN-NH2 were evaluated using rat cortex nerve terminals (synaptosomes). Results. MSN-NH2 did not influence the extracellular synaptosomal level of excitatory neurotransmitter L-[14C]glutamate and so did not cause excitotoxicity. In fluorescence measurements, MSN-NH2 depolarised the synaptosomal membrane and demonstrated weak antioxidant properties, decreasing the spontaneous generation of reactive oxygen species, whereas MSN-NH2 did not alter H2O2 in nerve terminals. The model of Cd2+/Pb2+/Hg2+-induced excitotoxicity was used to assess the capability of MSN-NH2 to adsorb xenobiotic heavy metals. MSN-NH2 did not modulate the Cd2+/Pb2+/Hg2+-induced increase in the extracellular synaptosomal level of L-[14C]glutamate. Conclusion. MSN-NH2 did not demonstrate excitotoxic signs, had weak antioxidant properties, and was biocompatible. MSN-NH2 did not mitigate the excitotoxic effects of xenobiotic heavy metals and did not adsorb these metals in biological systems.

Aim. Carbon particles have been widely used in different technologies and have great potential for new biological application. Synthesis of carbon particles from agricultural waste using “green” principles is in the mainstream of biotechnology area and attract a great attention in biomedical application. Here, coarse carbon particles (CCPs) were synthesized using “green” principles from dry apple and used in the biological experiments without preliminary functionalization. Methods. Neurotoxic features of CCPs were analysed in isolated presynaptic cortex nerve terminals (synaptosomes) monitoring the extracellular levels of excitatory neurotransmitter L-[14C] glutamate and inhibitory one [3H]GABA, as well as the membrane potential. Results. Measuring the membrane potential of the nerve terminals, it was revealed an inadequate decrease in the fluorescence intensity of the potential-dependent dye rhodamine 6G in the presence of CCPs (1 mg/ml). This decrease was not due to membrane hyperpolarisation because CCPs did not change the extracellular synaptosomal levels of L-[14C] glutamate and [3H]GABA. CCP-induced decrease in the fluorescence intensity of the dye in nerve terminals can be due to its interaction with CCPs. Indeed, the ability of CCPs to interact with rhodamine 6G was shown in synaptosome-free incubation media. Conclusions. Therefore, CCPs did not possess neurotoxic signs, and so are biocompatible. In both experiments, i.e. without bio object and in biological system, CCPs were able to interact with fluorescent dye rhodamine 6G. In prospect, this feature of CCPs can be used in biotechnology after further investigation of dye interaction conditions.

Heavy metals, Cd2+ and Pb2+, and carbonaceous air pollution particulate matter are hazardous neurotoxicants. Here, a capability of water-suspended smoke particulate matter preparations obtained from poplar wood (WPs) and polypropylene fibers (medical facemasks) (MPs) to influence Cd2+/Pb2+-induced neurotoxicity, and vice versa, was monitored using biological system, i.e. isolated presynaptic rat cortex nerve terminals. Combined application of Pb2+ and WPs/MPs to nerve terminals in an acute manner revealed that smoke preparations did not change a Pb2+-induced increase in the extracellular levels of excitatory neurotransmitter L-[14C]glutamate and inhibitory one [3H]GABA, thereby demonstrating additive result and no interference of neurotoxic effects of Pb2+ and particulate matter. Whereas, both smoke preparations decreased a Cd2+-induced increase in the extracellular level of L-[14C]glutamate and [3H]GABA in nerve terminals. In fluorimetric measurements, the metals and smoke preparations demonstrated additive effects on the membrane potential of nerve terminals causing membrane depolarisation. WPs/MPs-induced reduction of spontaneous ROS generation was mitigated by Cd2+ and Pb2+. Therefore, a potential variety of multipollutant heavy metal-/airborne particulate-induced effects on key presynaptic processes was revealed. Multipollutant reciprocal neurological hazard through disturbance of the excitation-inhibition balance, membrane potential and ROS generation was evidenced. This multipollutant approach and data contribute to up-to-date environmental quality/health risk estimation.

Here, water-suspended smoke aerosol preparation was synthesized from biomass-based fuel, i.e., a widespread product for residential heating, wood sawdust (WP) (pine, poplar, and birch mixture), and its properties were compared in parallel experiments with the smoke preparation from plastics (PP). Molecular groups in the PM preparations were analyzed using Raman and Fourier-transform infrared spectroscopy. WP was assessed in neurotoxicity studies using rat cortex nerve terminals (synaptosomes). Generation of spontaneous and H2O2-evoked reactive oxygen species (ROS) detected using fluorescent dye 2′,7′-dichlorofluorescein in nerve terminals was decreased by WP. In comparison with PP, WP demonstrated more pronounced reduction of spontaneous and H2O2-evoked ROS production. WP completely inhibited glutamate receptor agonist kainate-induced ROS production, thereby affecting the glutamate receptor-mediated signaling pathways. WP decreased the synaptosomal membrane potential in fluorimetric experiments and the synaptosomal transporter-mediated uptake of excitatory and inhibitory neurotransmitters, L-[14C]glutamate and [3H] γ-aminobutyric acid (GABA), respectively. PP decreased the ambient synaptosomal level of [3H]GABA, whereas it did not change that of L-[14C]glutamate. Principal difference between WP and PP was found in their ability to influence the ambient synaptosomal level of [3H]GABA (an increase and decrease, respectively), thereby showing riskiness in mitigation of synaptic inhibition by PP and triggering development of neuropathology.

The study aimed to develop a strategy and methodology for neuroprotection during long-term space missions, which is based on a comprehensive study of the impact of therapeutic hypothermia combined with the action of neuroactive drugs on the key characteristics of synaptic transmission in brain nerve terminals, which change under the influence of planetary dust and conditions of altered gravity. Development of neurotoxicity under conditions of altered gravity may result from excess extracellular glutamate caused by the reverse functioning of glutamate transporters. Under conditions of moderate and deep hypothermia, a gradual decrease in the transporter-mediated release of L-[14C]glutamate from nerve terminals was demonstrated, which is stimulated by plasma membrane depolarization with KCl and dissipation of the proton gradient of synaptic vesicles by the protonophore FCCP. This fact indicates a neuroprotective effect, which increases when hypothermia changes from moderate to deep. The possible risks of using hypothermia in space medicine have been determined. Hypothermia is not able to reduce the extracellular level of L-[14C]glutamate and [3H]GABA, which increases under the conditions of exposure to carbon-containing planetary dust. Hypothermia can lead to a further decrease in the rate of accumulation of neurotransmitters in the presence of carbon-containing planetary dust and to contribute to the development of neurotoxicity, which is a possible risk of using hypothermia in space medicine. In this context, it is important to choose the optimal individual temperature regime for each astronaut.

Here, clinical studies of patients were conducted to assess changes in patients with ulcerative colitis (UC) and irritable bowel syndrome (IBS) associated with air pollution by PM. A comparative study of 100 patients with UC and 75 with IBS from highly (HPRs) and low (LPRs) PM2.5-polluted regions of Ukraine was conducted. Biopsy of the intestinal mucosa of patients with UC from HPRs showed severe cellular infiltration. Patients with IBS from HPRs had changes in the superficial epithelium (focal desquamation), and inflammatory-cellular infiltration of mucous membrane of the colon. In patients with UC, changes in mucus production were found, which were more significant in HPR patients. PAS response did not depend on the residence; the level of MUC2 was significantly lower in HPR patients with UC (1.12 vs 2.15 au). In patients with UC from HPRs, a decrease in Bacteroidetes (34.0 vs. 39.0 small intestinal bacterial overgrowth (SIBO), ppm) and an increase in Proteobacteria compared to LPRs were shown. In IBS patients, significant differences were found in the level of Proteobacteria, which was higher in HPRs. The level of regulatory flora Akkermansia muciniphila and Faecalibacterium prausnitzii reduced in patients with UC from HPRs. In patients from LPRs, the level of Akkermansia muciniphila raised above normal (2.8 vs 4.7 SIBO, ppm). Similar changes of regulatory flora have been identified in patients with IBS from different regions. Therefore, a more severe course of the disease (more pronounced cellular infiltration and violation of the microbiota) was shown in patients with UC from HPRs as compared to LPRs.

Major source of carbon-containing air born particular matter that significantly pollutes environment and provokes development of neuropathology is forest fires and wood combustion. Here, water-suspended smoke particulate matter preparations (SPs) were synthesized from birch, pine, poplar wood, and also birch bark and pine needles. Taking into account importance of the gut-brain communication system, SP properties were compared regarding their capability to modulate functioning of nerve terminals and gut cells/preparations. In cortex nerve terminals, poplar wood SP was more effective in decreasing uptake and increasing the extracellular levels of excitatory and inhibitory neurotransmitters L-[14C]glutamate and [3H]GABA, respectively. Spontaneous and H2O2-stimulated ROS generation in nerve terminals decreased by SPs, the most efficient one was from poplar wood. SPs from birch, pine and poplar wood caused membrane depolarization, poplar wood SP effect was 5-fold higher vs. birch and pine wood ones. Functional characteristics of gut cells/preparations, which tightly related to nerve terminal experiments, were assessed. SPs increased paracellular permeability of proximal colon mucosalsubmucosal preparations monitored in Ussing chamber system (FITC-dextran, 4 kDa), where the most prominent effect had poplar wood SP. The latter demonstrated more considerable influence on COLO 205 cell causing 30 % loss of cell viability. PM emitted to the environment during combustion of various wood caused similar unidirectional harmful effects on brain and gut cell functioning, thereby triggering development of pathologies in gut and brain and gut-brain communication system.

Smoke from plastic waste incineration in an open air travels worldwide and is a major source of air pollution particulate matter (PM) that is very withstand to degradation and hazard to human health. Suspension of smoke aerosol components in water occurs during rains and fire extinguishing. Here, water-suspended plastic smoke aerosol (WPS) preparations suitable for biotesting were synthesized. It has been revealed using dynamic light scattering that WPS contained major nano-sized (similar to 30 nm) PM fraction, and this result was confirmed by electron microscopy. Optical absorption of WPS was in the UV region and an increase in lambda(ex) led to a red-shift in fluorescence emission with a corresponding decrease in fluorescence intensity. WPS was analyzed in neurotoxicity studies in vitro using presynaptic rat cortex nerve terminals (synaptosomes). Generation of spontaneous reactive oxygen species (ROS) detected using fluorescent dye 2',7-dichlorofluorescein in nerve terminals was decreased by WPS (10-50 mg/ml) in a dose-dependent manner. WPS also reduced the H2O2-evoked ROS production in synaptosomes, thereby influencing cellular oxidative processes and this effect was similar to that for carbon nanodots. WPS (0.1 mg/ml) decreased the synaptosomal membrane potential and synaptic vesicle acidification in fluorimetric experiments. WPS (1.0 mg/ml) attenuated the synaptosomal transporter-mediated uptake of excitatory and inhibitory neurotransmitters, L-[C-14]glutamate and [H-3]GABA, respectively. This can lead to an excessive increase in the glutamate concentration in the synaptic cleft and neurotoxicity via over activation of ionotropic glutamate receptors. Therefore, WPS was neurotoxic and provoked presynaptic malfunction through changes of oxidative activity, reduction of the membrane potential, synaptic vesicle acidification, and transporter-mediated uptake of excitatory and inhibitory neurotransmitters in nerve terminals. In summary, synthesis and emission to the environment of ultrafine PM occur during combustion of plastics, thereby polluting air and water resources, and possibly triggering development of neuropathologies. (c) 2020 Elsevier Ltd. All rights reserved.

Within this survey we describe the conceptual architecture of the infrastructure to measure PM2.5/PM10 concentration in the atmosphere over the Kyiv city using modern monitoring instruments. We define the requirements for information tools and network for informing Kyiv city community on the state of PM pollutions that will be created. This infrastructure will provide long-term PM2.5/PM10 observations that could be included in the AirBase network. The comprehensive review of in-situ and satellite measurements of PM2.5/PM10 is provided as well as the description current state-of-the-art for Air Quality monitoring with intelligent sensors and systems in Ukraine as-awhole and in Kyiv in particular. It is proposed to apply the concept of essential variables (EVs) used in Earth Observation to identify the variables that should be measured in priority when designing, deploying and maintaining observation systems. In this study we use and validate the global air quality products from Copernicus Atmosphere Monitoring Service obtained from modeling by GEOS-Chem model and other sources. The influence of PM and aerosols on a human health is estimated in terms of possible diseases and dangerous concentrations.

The importance of assessing the neurotoxic potential of nanoparticles is underscored by two main factors. From one side, nanoparticles are a perspective matter for use in neurotheranostics, neurosurgery, cancer treatment, and others branches of nanomedicine. From the other side, they are a component of air pollution that is considered to be a potential trigger factor for development of neuropathologies. The novelty of nanoparticle-related research is determined by unexpected physical and chemical properties of nanomaterials that often differ from those in bulk forms. Herein, we performed a comparative analysis of the neuromodulatory effects of synthesized detonation nanodiamonds, carbon dots, nanoparticles from native volcanic ash, and physiological ferritin-based nanoparticles using similar methodological approaches.

An excess of the excitatory neurotransmitter, glutamate, in the synaptic cleft during hypoxia/ischemia provokes development of neurotoxicity and originates from the reversal of Na+-dependent glutamate transporters located in the plasma membrane of presynaptic brain nerve terminals. Here, we have optimized an electrochemical glutamate biosensor using glutamate oxidase and developed a biosensor-based methodological approach for analysis of rates of tonic, exocytotic and transporter-mediated glutamate release from isolated rat brain nerve terminals (synaptosomes). Changes in the extracellular glutamate concentrations from 11.5 ± 0.9 to 11.7 ± 0.9 μΜ for 6 min reflected a low tonic release of endogenous glutamate from nerve terminals. Depolarization-induced exocytotic release of endogenous glutamate was equal to 7.5 ± 1.0 μΜ and transporter reversal was 8.0 ± 1.0 μΜ for 6 min. The biosensor data correlated well with the results obtained using radiolabelled L-[14C]glutamate, spectrofluorimetric glutamate dehydrogenase and amino acid analyzer assays. The blood plasma glutamate concentration was also tested, and reliability of the biosensor measurements was confirmed by glutamate dehydrogenase assay. Therefore, the biosensor-based approach for accurate monitoring rates of tonic, exocytotic and transporter-mediated release of glutamate in nerve terminals was developed and its adequacy was confirmed by independent analytical methods. The biosensor measurements provided precise data on changes in the concentrations of endogenous glutamate in nerve terminals in response to stimulation. We consider that the glutamate biosensor-based approach can be applied in clinics for neuromonitoring glutamate-related parameters in brain samples, liquids and blood plasma in stroke, brain trauma, therapeutic hypothermia treatment, etc., and also in laboratory work to record glutamate release and uptake kinetics in nerve terminals.

The manned extraterrestrial missions and planetary exploration require an assessment of the toxicity of planetary dust. Preparation of perspective space missions (especially Lunar station-related upcoming plans) requires urgent development of a methodology for the rapid assessment of toxicity of environmental compounds. Recently, the working group of the project was the first who showed the absence of significant neurotoxic effects of Lunar and Martian dust simulants, but the toxic properties of a mixture of Martian dust simulant particles and carbon nanoparticles. These experimental data were published in peer-reviewed journals, such as Microgravity Science and Technology (Pozdnyakova et al., 2017) and in the special issue of American Institute of Aeronautics and Astronautics (Dunne et al., 2010). The proposed project involves the development of a new methodology, evaluation algorithm, and equipment, as well as relevant models that can predict and determine the biosecurity of dust particles.

Specific rare earth doped nanocrystals (NCs), a recent class of nanoparticles with fluorescent features, have great bioanalytical potential. Neuroactive properties of NaYF4 nanocrystals doped with Eu3+ were assessed based on the analysis of their effects on glutamate- and γ-aminobutyric acid (GABA) transport process in nerve terminals isolated from rat brain (synaptosomes). Two types of hydrophilic NCs were examined in this work: (i) coated by polyethylene glycol (PEG) and (ii) with OH groups at the surface. It was found that NaYF4:Eu3+-PEG and NaYF4:Eu3+-OH within the concentration range of 0.5–3.5 and 0.5–1.5 mg/ml, respectively, did not influence Na+-dependent transporter-dependent l-[14C]glutamate and [3H]GABA uptake and the ambient level of the neurotransmitters in the synaptosomes. An increase in NaYF4:Eu3+-PEG and NaYF4:Eu3+-OH concentrations up to 7.5 and 3.5 mg/ml, respectively, led to the (1) attenuation of the initial velocity of uptake of l-[14C]glutamate and [3H]GABA and (2) elevation of ambient neurotransmitters in the suspension of nerve terminals. In the mentioned concentrations, nanocrystals did not influence acidification of synaptic vesicles that was shown with pH-sensitive fluorescent dye acridine orange, however, decreased the potential of the plasma membrane of synaptosomes. In comparison with other nanoparticles studied with similar methodological approach, NCs start to exhibit their effects on neurotransmitter transport at concentrations several times higher than those shown for carbon dots, detonation nanodiamonds and an iron storage protein ferritin, whose activity can be registered at 0.08, 0.5 and 0.08 mg/ml, respectively. Therefore, NCs can be considered lesser neurotoxic as compared to above nanoparticles.

Carbon is the most abundant dust-forming element in the interstellar medium. Tremendous amount of meteorites containing plentiful carbon and carbon-enriched dust particles have reached the Earth daily. National Institute of Health panel accumulates evidences that nano-sized air pollution components may have a significant impact on the central nervous system (CNS) in health and disease. During inhalation, nano-/microsized particles are efficiently deposited in nasal, tracheobronchial, and alveolar regions and can be transported to the CNS. Based on above facts, here we present the study, the aims of which were: 1) to upgrade inorganic Martian dust simulant derived from volcanic ash (JSC-1a/JSC, ORBITEC Orbital Technologies Corporation, Madison, Wisconsin) by the addition of carbon components, that is, nanodiamonds and carbon dots; 2) to analyse acute effects of upgraded simulant on key characteristics of synaptic neurotransmission; and 3) to compare above effects with those of inorganic dust and carbon components per se. Acute administration of carbon-containing Martian dust analogues resulted in a significant decrease in transporter-mediated uptake of L-[14C]glutamate (the major excitatory neurotransmitter) and [3H]GABA (the main inhibitory neurotransmitter) by isolated rat brain nerve terminals. The extracellular level of both neurotransmitters increased in the presence of carbon-containing Martian dust analogues. These effects were associated with action of carbon components of upgraded Martian dust simulant, but not with its inorganic constituent. This fact indicates that carbon component of native Martian dust can have deleterious effects on extracellular glutamate and GABA homeostasis in the CNS, and so glutamate- and GABA-ergic neurotransmission disballansing exitation and inhibition.

Carbon nanoparticles that may be potent air pollutants with adverse effects on human health often contain heteroatoms including sulfur. In order to study in detail their effects on different physiological and biochemical processes, artificially produced carbon dots (CDs) with well-controlled composition that allows fluorescence detection may be of great use. Having been prepared from different types of organic precursors, CDs expose different atoms at their surface suggesting a broad variation of functional groups. Recently, we demonstrated neurotoxic properties of CDs synthesized from the amino acid β-alanine, and it is of importance to analyze whether CDs obtained from different precursors and particularly those exposing sulfur atoms induce similar neurotoxic effects. This study focused on synthesis of CDs from the sulfur-containing precursor thiourea-CDs (TU-CDs) with a size less than 10 nm, their characterization, and neuroactivity assessment. Neuroactive properties of TU-CDs were analyzed based on their effects on the key characteristics of glutamatergic and γ-aminobutyric acid (GABA) neurotransmission in isolated rat brain nerve terminals. It was observed that TU-CDs (0.5–1.0 mg/ml) attenuated the initial velocity of Na+-dependent transporter-mediated uptake and accumulation of l-[14C]glutamate and [3H]GABA by nerve terminals in a dose-dependent manner and increased the ambient level of the neurotransmitters. Starting from the concentration of 0.2 mg/ml, TU-CDs evoked a gradual dose-dependent depolarization of the plasma membrane of nerve terminals measured with the cationic potentiometric dye rhodamine 6G. Within the concentration range of 0.1–0.5 mg/ml, TU-CDs caused an “unphysiological” step-like increase in fluorescence intensity of the рН-sensitive fluorescent dye acridine orange accumulated by synaptic vesicles. Therefore, despite different surface properties and fluorescent features of CDs prepared from different starting materials (thiourea and β-alanine), their principal neurotoxic effects are analogous but displayed at a different level of efficiency. Sulfur-containing TU-CDs exhibit lower effects (by ~30%) on glutamate and GABA transport in the nerve terminals in comparison with sulfur-free β-alanine CDs. Our results suggest considering that an uncontrolled presence of carbon-containing particulate matter in the human environment may pose a toxicity risk for the central nervous system.