Hydrogen Nanobubbles Research Articles

Mitigating environmental toxicity with hydrogen nanobubbles: A mitochondrial function-based approach to ecological restoration

In biological systems, nanobubbles (NBs) effectively enhance hydrogen molecule retention and scavenging reactive oxygen species (ROS), but the underlying mechanisms remain elusive. To investigate this, we prepared hydrogen NB water samples with consistent dissolved hydrogen levels but varying NB densities to explore their physicochemical properties and effects on green algae (Chlorella vulgaris) under oxidative stress induced by copper ions (Cu2+) and cadmium ions (Cd2+). The results indicated a strong correlation between the hydrogen NB number density and the 25 % inhibitory concentration of Cu2+ over 24 h, with ROS removal efficiency increased with the NB number density. Gas chromatography showed that the hydrogen NBs in the solution had a high gas density that enhanced hydrogen transport into C. vulgaris. With regard to mitochondrial activity, hydrogen NBs were observed to enhance the function of mitochondrial complexes I and V and increase the mitochondrial membrane potential. Experiments with C. vulgaris mitochondrial electrodes showed that the electron transfer rates increased significantly in the presence of hydrogen NBs. We concluded that the high gas density of hydrogen NBs augments intracellular hydrogen delivery and strengthens mitochondrial functions.

High‐Speed AFM Observation of Electrolytic Hydrogen Nanobubbles During Potential Scanning

High‐Speed AFM Observation of Electrolytic Hydrogen Nanobubbles During Potential Scanning

Hydrogen nanobubbles and oxidative windows: Investigating how varying hydrogen concentrations influence seed germination and stress defense

The hydrogen molecule can effectively regulate plant growth and development, improving plant resistance to abiotic stresses. However, studies regarding the optimal concentration of hydrogen and the associated mechanisms of action in organisms are lacking. This study showed that the maximum germination rate of radish seeds decreased from 90 % to 50 % under the stress of cadmium ions (Cd2+), and hydrogen nanobubble (NB) water significantly alleviated the stress effect of Cd2+ on radish seed germination. A hydrogen concentration of 0.8 ppm had the best effect, reducing Cd2+ accumulation in radish seeds by 63.23 % and increasing the maximum germination rate from 50 % to 65 %. At concentrations exceeding 1.2 ppm, the beneficial effect of hydrogen was weakened or even reversed. Consequently, we integrated the concept of the oxidative window into a REDOX balance model and demonstrated that an appropriate hydrogen concentration can effectively maintain the REDOX state within organisms. Transcriptome sequencing analysis revealed that hydrogen NB water modulated Cd2+ absorption and accumulation in seeds by regulating cell wall components, alleviating oxidative stress through oxidoreductase activity, and enhancing nutrient synthesis and metabolism. This collectively alleviated the inhibitory effect of Cd2+ on seed germination. This study is helpful for further understanding the effect of hydrogen concentration on the REDOX balance of seed germination, providing a theoretical basis for selecting hydrogen concentration to improve its effectiveness in agricultural fields.

In-situ observation of hydrogen nanobubbles formation on graphene surface by AFM-SECM

Gas bubble evolution is an important phenomenon in many electrochemical processes and it is highly sensitive to the surface properties. Here we visualize the gas bubble dynamics on the surface of different graphene substrates during hydrogen evolution reaction (HER) using atomic force microscopy combined with scanning electrochemical microscopy. The low overpotential and low surface hydrophobicity of few-layer graphene formed on C-phase SiC causes the uniform distribution of hydrogen nanobubbles, which easily depart from the surface during the reaction. Conversely, the high overpotential and more hydrophobic surface of HOPG induces hydrogen bubbles to linger on the surface for an extended duration, leading to its accumulation and the subsequent formation of microbubbles. This in-situ nanoscale electrochemical mapping of hydrogen bubble dynamics provides new insight into electrocatalytic HER that occurs on non-metal electrodes.

Enhancing tomato fruit antioxidant potential through hydrogen nanobubble irrigation.

Eating fruits and vegetables loaded with natural antioxidants can boost human health considerably and help fight off diseases linked to oxidative stress. Hydrogen has unique antioxidant effects. However, its low-solubility and fast-diffusion has limited its applications in agriculture. Integration of hydrogen with nanobubble technology could address such problems. However, the physiological adaptation and response mechanism of crops to hydrogen nanobubbles is still poorly understood. Antioxidant concentrations of lycopene, ascorbic acid, flavonoids, and resveratrol in hydrogen nanobubble water drip-irrigated tomato fruits increased by 16.3-264.8% and 2.2-19.8%, respectively, compared to underground water and oxygen nanobubble water. Transcriptomic and metabolomic analyses were combined to investigate the regulatory mechanisms that differed from the controls. Comprehensive multi-omics analysis revealed differences in the abundances of genes responsible for hormonal control, hydrogenase genes, and necessary synthetic metabolites of antioxidants, which helped to clarify the observed improvements in antioxidants. This is the first case of hydrogen nanobubble water irrigation increasing numerous natural antioxidant parts in fruits. Considering the characteristics of hydrogen and the application of the nanobubble technology in agriculture, the findings of the present study could facilitate the understanding of the potential effects of hydrogen on biological processes and the mechanisms of action on plant growth and development.

Advantages of hydrogen nanobubble-rich concrete in workability and mechanical properties

This study investigates the potential benefits of using the 150 nm level Hydrogen Nanobubble Water (HNBW) in cement concrete. Given the significant greenhouse gas emissions associated with the cement and concrete industry, enhancing building materials performance and environmental friendliness becomes crucial. In this work, experiments were conducted to evaluate the various properties of this particular concrete formulation such as hydration heat, compressive strength, slump, air content, water absorption, electrical resistivity, rapid chloride permeability, and SEM. The results of the analysis showed that the HNBW improved the workability of the concrete by 50%. The HNBW improved the mechanical properties and durability of the concrete, resulting in an increase in compressive strength of 18.03% at 3 days and over 6% at 7 and 28 days. It reduces water absorption while improving electrical resistivity and chloride permeability resistance. Additionally, SEM imaging confirms that HNBW contributes to a more compact structure with pore and micro-crack size, thereby improving the overall performance of the concrete. Therefore, hydrogen nanobubbles, as a nanomaterial, exhibit favorable effects in meeting the demands of concrete.

Hydrogen Nanobubbles Generated In Situ from Nanoscale Zerovalent Iron with Water to Further Enhance Selenite Sequestration.

Gas nanobubbles used for water treatment and recovery give rise to great concern for their unique advantages of less byproducts, higher efficiency, and environmental friendliness. Nanoscale zerovalent iron (nZVI), which has also been widely explored in the field of environmental remediation, can generate gas hydrogen by direct reaction with water. Whether nanoscale hydrogen bubbles can be produced to enhance the pollution removal of the nZVI system is one significant concern involved. Herein, we report direct observations of in situ generation of hydrogen nanobubbles (HNBs) from nZVI in water. More importantly, the formed HNBs can enhance indeed the reduction of Se(IV) beyond the chemical reduction ascribed to Fe(0), especially in the anaerobic environment. The possible mechanism is that HNBs enhance the reducibility of the system and promote electron transport in the solution. This study demonstrates a unique function of HNBs combined with nZVI for the pollutant removal and a new approach for in situ HNB generation for potential applications in the fields of in situ remediation agriculture, biotechnology, medical treatment, health, etc.

Hydrogen nanobubbles: A novel approach toward radio-sensitization agents.

Ocular melanoma is a rare kind of eye malignancy that threatens the patient's eyesight. Radiotherapy and surgical removal are the most commonly used therapeutic modalities, and nanomedicine has lately entered this field. Brachytherapy using Ruthenium-106 (106 Ru) ophthalmic plaques has been used for decades to treat ocular melanoma, with the applicator placed on the patient's eyes until the prescribed dose reaches the tumor apex. To investigate the efficiency of hydrogen nanobubbles (H2 -NBs) employment during intraocular melanoma brachytherapy using a 106 Ru electron emitter plaque. The Monte Carlo (MC) simulation and experimental investigation using a 3D-designed phantom and thermoluminescence dosimetry (TLD) were employed. Various concentrations of H2 -NBs with a diameter of 100nm were simulated inside tumor tissue. The results were presented as deposited energy and dose enhancement factor (DEF). An equivalent Resin phantom of the human eyeball was made using AutoCAD and 3D-Printer technologies. The glass-bead TLDs dosimeter were employed and placed inside the phantom. Using a 1% concentration of H2 -NBs, a DEF of 93% and 98% were achieved at the tumor apex of 10mm from the experimental setup and MC simulation, respectively. For simulated concentrations of 0.1%, 0.3%, 0.5%, 1%, and 4% H2 -NBs, a maximum dose enhancement of 154%, 174%, 188%, 200%, and 300% were achieved, respectively, and a dose reduction was seen at about 3mm from the plaque surface. H2 -NBs can be used as an absorbed dose enhancer in 106 Ru eye brachytherapy because of their unique physical characteristics. Reducing plaque implantation time on the patient's eye, reducing sclera absorbed dose, and decreasing the risk of patients' healthy organs irradiation are reported as some of the potential benefits of using H2-NBs.

Enhanced Removal of Free Radicals by Aqueous Hydrogen Nanobubbles and Their Role in Oxidative Stress.

Elevated levels of reactive oxygen radicals caused by environmental stress are the key triggers of inflammation, aging, and disease; thus, it is critical to develop novel reactive oxygen radical scavenging methods with high efficiency and low toxicity. As a result of their selective reactive oxygen radical removal, hydrogen molecules are strong candidates, but their application is limited by the small hydrogen supply and short duration of action. In this study, we for the first time combined nanobubble (NB) technology and hydrogen water to remove reactive oxygen species (ROS) using copper ions as a representative environmental pollutant and Tetrahymena thermophila as a model organism. Hydrogen NBs displayed a remarkable capability of removing H2O2 and O2•- at molar ratios of 8:1 and 240:1, respectively, which were unable to be removed by dissolved hydrogen molecules only. During the oxidative defense phase, hydrogen NB water either directly removed ROS or increased the activity and relative expression of glutathione peroxidase (GSH-Px). During the oxidative inhibition phase, hydrogen NB water exerted antioxidant effects mainly by increasing the activities of superoxide dismutase and GSH-Px as well as the expression of the corresponding genes. Our results provide an important theoretical support for the wide application of hydrogen NBs in empowering the antioxidant defense system.

Physicochemical properties and detergency of special electrolytic-reduction ion water.

The detergency of special electrolytic-reduction ion water (S-100) was evaluated in comparison with typical synthetic surfactants. Furthermore, to examine the cleaning mechanism of S-100, various physicochemical characteristics of S-100 were measured and a comprehensive evaluation of cleaning was performed. S-100 (10%) had a detergency comparable to that of various surfactants, such as sodium dodecyl sulfate and sodium dodecyl benzene sulfonate, which are generally blended or mixed in residential detergents. In addition, concentrated aqueous solutions of 10% or more of S-100 showed stronger detergency. The cleaning mechanism of S-100 is mainly attributed to the effect of surface tension reduction due to dissolved hydrogen or hydrogen nanobubbles in S-100, and the alkalinity generated by electrolysis charged the surface of the dirt or adherend, resulting in a peeling effect.

Punching of arbitrary face prismatic loops from hydrogen nanobubbles in copper

When a metal surface is exposed to prolonged irradiation with energetic H−, the ions are expected to penetrate into bulk and dissolve in the matrix. However, the irradiated surfaces exhibit dramatic morphological changes in the form of “blisters” covering the surface exposed to irradiation. Blistering is usually explained by accumulation of implanted gas in the bubbles near surface. However, the exact mechanism of continuous growth of a bubble after it reaches the measurable size is still not fully clear. Commonly such growth is related to prismatic loop punching, which is a short time scale process not easily accessible by experimental techniques. Even atomistic modelling of loop punching in FCC metals is somewhat cumbersome. Since the void surfaces in these metals yield easily through shear loops, these were debatably suggested to explain the plastic growth of a bubble in copper, without demonstrating the detachment of these loops from the void.We address the mechanisms of fast bubble growth in Cu which is associated with blistering of Cu surface exposed to H− irradiation. We observe the emission of a complete prismatic loop enclosed within the number of shear loops with the Burgers vectors aligned with the gliding direction of the prismatic loop. We show that the prismatic loops punched from the bubble surface do not need to be smaller than the bubble cross-section. These simulations capture the general trend of dislocation emission in the condition of hydrostatic pressure exerted by the accumulated gas on the wall of the bubble.

Nanobubble Labeling and Imaging with a Solvatochromic Fluorophore Nile Red.

Herein, we report the use of a polarity-sensitive, solvatochromic fluorophore Nile red to label and probe individual hydrogen nanobubbles on the surface of an indium-tin oxide (ITO) electrode. Nanobubbles are generated from the reduction of water on ITO and fluorescently imaged from the transient adsorption and desorption process of single Nile red molecules at the nanobubble surface. The ability to label and fluorescently image individual nanobubbles with Nile red suggests that the gas/solution interface is hydrophobic in nature. Compared to the short labeling events using rhodamine fluorophores, Nile red-labeled events appear to be longer in duration, suggesting that Nile red has a higher affinity to the bubble surface. The stronger fluorophore-bubble interaction also leads to certain nanobubbles being co-labeled by multiple Nile red molecules, resulting in the observation of super-bright and long-lasting labeling events. Based on these interesting observations, we hypothesize that Nile red molecules may start clustering and form some kind of molecular aggregates when they are co-adsorbed on the same nanobubble surface. The ability to observe super-bright and long-lasting multifluorophore labeling events also allows us to verify the high stability and long lifetime of electrochemically generated surface nanobubbles.

Effect of Hydrogen Nanobubbles on the Mechanical Strength and Watertightness of Cement Mixtures.

This study analyzed the effects of applying highly concentrated hydrogen nanobubble water (HNBW) on the workability, durability, watertightness, and microstructure of cement mixtures. The number of hydrogen nanobubbles was concentrated twofold to a more stable state using osmosis. The compressive strength of the cement mortar for each curing day was improved by about 3.7–15.79%, compared to the specimen that used general water, when two concentrations of HNBW were used as the mixing water. The results of mercury intrusion porosimetry and a scanning electron microscope analysis of the cement paste showed that the pore volume of the specimen decreased by about 4.38–10.26%, thereby improving the watertightness when high-concentration HNBW was used. The improvement in strength and watertightness is a result of the reduction of the microbubbles’ particle size, and the increase in the zeta potential and surface tension, which activated the hydration reaction of the cement and accelerated the pozzolanic reaction.

Free radical degradation in aqueous solution by blowing hydrogen and carbon dioxide nanobubbles

The main findings are the hydroxyl radical scavenging and the superoxide anion diminishing by mixing the carbon dioxide (CO2) nanobubbles after hydrogen nanobubble blowing in water and alcohol aqueous solution. The nanobubbles produce the hydroxyl radical by ultrasonic waves, changing the pH and catalyst and so on, while the nanobubble is very reactive to scavenge free radicals. In this research especially hydrogen (4% H2 in argon) and CO2 nanobubbles have been blown into hydrogen peroxide (H2O2) added pure water, ethanol, and ethylene glycol aqueous solution through a porous ceramic sparger from the gas cylinder. The aqueous solutions with H2O2 are irradiated by ultraviolet (UV) light and the produced hydroxyl radical amount is measured with spin trapping reagent and electron spin resonance (ESR). The CO2 nanobubble blowing extremely has reduced the hydroxyl radical in water, ethanol, and ethylene glycol aqueous solution. On the other hand, when H2 nanobubbles are brown after CO2 nanobubble blowing, the hydroxyl radical amount has increased. For the disinfection test, the increase of hydroxyl radicals is useful to reduce the bacteria by the observation in the agar medium. Next, when the superoxide anion solution is mixed with nanobubble containing water, ethanol, and ethylene glycol aqueous solution, H2 nanobubble has reduced the superoxide anion slightly. The water containing both CO2 and H2 nanobubble reduces the superoxide anion. The less than 20% ethanol and the 30% ethylene glycol aqueous solution containing CO2 nanobubbles generated after H2 nanobubble blowing can diminish the superoxide anion much more. While the H2 nanobubble blowing after CO2 nanobubble blowing scavenges the superoxide anion slightly. The experimental results have been considered using a chemical reaction formula.

Voltammetric Analysis of Single Nanobubble Formation on Ag and Ag@MoS2 Nanoelectrodes

The nucleation of single hydrogen (H2) nanobubbles is explored in Ag nanoelectrodes (NEs, radius is 5–65 nm), where H2 is produced through proton electroreduction in H2SO4 solution. Moreover, Ag NE...

A Bubble-STORM Approach for Super-Resolved Imaging of Nucleation Sites in Hydrogen Evolution Reactions.

Stochastic optical reconstruction microscopy (STORM) is a powerful strategy to achieve super-resolved imaging of biological structures by virtue of the stochastic photoactivation of fluorophores and superlocalization algorithm. Herein, we report a fluorophore-free bubble-STORM approach for super-resolved imaging of nucleation sites in hydrogen evolution reactions (HER). When applying an appropriate pulse potential to the electrode, rapid electro-reduction of protons created a local oversaturation of hydrogen molecules and thus the nucleation of sparsely distributed hydrogen nanobubbles. A surface plasmon resonance microscopy was employed to monitor the process and report the localization of each nanobubble via superlocalization fitting. The withdrawal of electrode potential, or the microconvection, led to the immediate disappearance of nanobubbles and recovered the electrode surface before the next pulse. By repeating the procedures for thousands of cycles, one was able to reconstruct a map of nucleation sites with a spatial resolution beyond the optical diffraction limit. This approach does not require a model fluorogenic reaction or fluorescent labeling to the nanobubbles, thus revealing the intrinsic nucleation sites in the natural states. Our results further indicated the fast growth, coalescence, and detachment behaviors of nanobubbles on a time scale of sub-milliseconds, underscoring the significance of high temporal resolution for studying nanobubble nucleation.

Hydrogen-bubbled platinum-colloid suppresses human esophagus- or tongue-carcinoma cells with intracellular platinum-uptake and the diminished normal-cell mortality.

Carcinostatic effects of combined use of hydrogen nano-bubbles (nano-H) and platinum-povidone (PVP--Pt) were examined. Hydrogen-dissolved medium was prepared by hydrogen-gas bubbling with a microporous gas-emittance-terminal into a medium in the absence or presence of PVP-Pt (nano-H, nano-H/PVP-Pt). Human esophagus-derived carcinoma cells KYSE70 were repressed for cell proliferation with nano-H/PVP-Pt more markedly than with nano-H, indicating the hydrogen-intensification for PVP-Pt-alone-carcinostasis. However, the intensified carcinostasis required co-administration of nano-H and PVP-Pt, and no intensified carcinostasis was shown in two-step separate administration of nano-H and PVP-Pt. Furthermore, hydrogen bubbling into PVP-Pt-containing medium achieved more appreciable carcinostasis than mere addition of PVP-Pt into nano-H-containing medium, indicating the potent interaction of hydrogen and PVP-Pt. The nano-H/PVP-Pt-administered human tongue-derived carcinoma cells HSC-4 were repressed for cell proliferation more markedly than pre-malignant human tongue-derived epitheliocytes DOK, concurrently with more abundant intracellular Pt-intake into HSC-4 cells than DOK as analyzed by ICP-MS. Thus, PVP-Pt is able to adsorb hydrogen nano-bubbles on Pt and applicable for cancer therapy by diminishing the side-effects to normal cells.

Accelerated Formation of H2 Nanobubbles from a Surface Nanodroplet Reaction.

The compartmentalization of chemical reactions within droplets has advantages in low costs, reduced consumption of reagents, and increased throughput. Reactions in small droplets have also been shown to greatly accelerate the rate of many chemical reactions. The accelerated growth rate of nanobubbles from nanodroplet reactions is demonstrated in this work. The gaseous products from the reaction at the nanodroplet surface promoted nucleation of hydrogen nanobubbles within multiple organic liquid nanodroplets. The nanobubbles were confined within the droplets and selectively grew and collapsed at the droplet perimeter, as visualized by microscopy with high spatial and temporal resolutions. The growth rate of the bubbles was significantly accelerated within small droplets and scaled inversely with droplet radius. The acceleration was attributed to confinement from the droplet volume and effect from the surface area on the interfacial chemical reaction for gas production. The results of this study provide further understanding for applications in droplet enhanced production of nanobubbles and the on-demand liberation of hydrogen.

Remediation of Copper Contaminated Soils Using Water Containing Hydrogen Nanobubbles

This basic research study was undertaken to use ecofriendly nanobubbles that can improve the electrokinetic remediation of copper-contaminated soil, as well as to determine that remediation efficiency. The nanobubbles were generated by using pressurized hydrogen gas, and the quantity of hydrogen gas bubble that remained over 14 days was measured. The generated nanobubbles were used as an enhancer to remove a heavy metal on contaminated soil, and their applicability was confirmed. A batch test was used to compare the remediation effects of nanobubbles and distilled water on copper-contaminated soil. The results proved that the nanobubbles are a proper desorption agent for copper-contaminated sand and clay specimens. The solid–liquid ratio and the contact time for desorption of the sand and clay were then respectively determined. A large amount of effluent was obtained from electrokinetic remediation of the sand sample after applying the nanobubbles as an enhancer. The remediation efficiency demonstrated with sand proved to be higher than that for clay. This greater efficiency was attributed to a wider specific surface area, demonstrating the potential use of the nanobubbles as an enhancer for soil contaminated by copper with a large amount of effluent outflow. It was also assumed to be affected by the moving capability of the nanobubbles in the soil layer. Thus, the nanobubbled water can be used to improve the removal of heavy metals from contaminated soils. An ecofriendly enhancer for electrokinetic remediation with a relatively large void ratio and fast flowrate was confirmed by the nanobubbles.

An Experimental Study on Bubble Collapsing Effect of Nanobubble Using Ultrasonic Wave.

The nanobubbles generated in water are large in non-surface aspect that allows the formation of radicals on their surface. Nanobubbles maintain high pressure inside, and are capable of Brownian motion Most of nanobubbles based research focused on the characteristic of nanobubble to maintain high pressure inside while it shrunk. High temperature was generated when bubble was collapsed by an external impact. In this study, hydrogen nanobubbles were produced based on a self-technique that could store nanobubbles for a long period. The test was conducted to destroy nanobubbles in hydrogen nanobubble water. Ultrasonic waves were applied into the water to destroy nanobubbles and there was rise in water temperature, which was caused by the collapsing effect of bubbles. When ultrasonic waves were applied, the collapsing effect of bubbles was largely exhibited within the initial one minute of the experiment. It was confirmed that the wattage of ultrasonic wave was significantly affected. If the collapsing effect of nanobubbles can be measured, it will be possible to apply this method positively to various fields.