STUDIES
Ultrasonic Cleaning
Testing the effectiveness of ultrasonic cleaning between water and NB water on grease.
Evaluating Photodynamic and Nanobubble-Ultrasound Technologies for Antimicrobial Efficacy
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Photodynamic Inactivation (PDI):
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Utilizing LED (470 nm) and UV-A (400 nm)-activated curcumin, PDI achieved:
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Complete elimination of V. parahaemolyticus at 4°C and 22°C.
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Greater than 2 log cfu/mL reduction of A. hydrophila in a concentration-dependent manner (p < 0.05).
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In aquaponic water samples, PDI caused:
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6 log cfu/mL reduction of V. parahaemolyticus.
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4 log cfu/mL reduction of A. hydrophila (p < 0.05).
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Nanobubble Technology:
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Nanobubbles alone had negligible antimicrobial effects (p > 0.05).
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When combined with ultrasound:
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6 log cfu/mL reduction of A. hydrophila.
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3 log cfu/mL reduction of V. parahaemolyticus (p < 0.05).
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Key Findings:
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Both approaches demonstrated significant efficacy in reducing pathogen levels in aquaponic systems.
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Combining nanobubbles with ultrasound enhances antimicrobial performance, while photodynamic inactivation offers a chemical-free alternative.
These methods show potential as novel, sustainable strategies for managing fish and shellfish pathogens in aquaculture systems
Development of an effective cleaning method for metallic parts using microbubbles
Summary: Combining Microbubble Flotation and Ultrasound for Efficient Cleaning
This study explores the use of microbubble flotation as a sustainable and efficient method for cleaning oil-contaminated metallic parts, comparing its performance with ultrasonic cleaning:
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Microbubble Flotation Effectiveness:
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Initial trials using microbubble flotation with deionized water removed 60% of oil from metallic parts.
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System modifications, such as adjusting the flotation tank design and inlet position, improved oil removal efficiency to 80–90% within 15 minutes.
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Comparison with Ultrasonic Cleaning:
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Microbubble cleaning demonstrated lower power consumption compared to ultrasonic cleaning, especially for large volumes of metallic parts.
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Ultrasonic cleaning, while effective, risks surface damage and requires higher maintenance costs due to bubble collapse near transducers.
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Key Findings on Microbubble Efficiency:
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Smaller microbubbles (with diameters less than 50 μm) provided a larger surface area, enhancing contaminant aggregation and separation efficiency.
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The chemical-free nature of microbubble technology supports environmentally friendly operations.
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Combining Microbubbles with Ultrasonication:
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While the study focused on microbubble flotation alone, coupling microbubbles with ultrasonic waves could further enhance cleaning performance by leveraging the physical agitation of ultrasonics and the contaminant-separation efficiency of microbubbles.
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Green Cleaning Approach:
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This method offers a sustainable alternative to traditional chlorinated solvents and high-power ultrasonic cleaning, reducing toxic emissions, energy use, and maintenance costs.
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Conclusion:
Microbubble flotation provides an energy-efficient, eco-friendly solution for cleaning oil-contaminated metallic parts, achieving comparable or superior results to ultrasonic cleaning. Its combination with ultrasonication holds potential for even greater cleaning efficacy while minimizing environmental impact.
Summary: Eco-Friendly Microbubble Cleaning for Oil Removal
This study demonstrates the effectiveness of microbubbles as a sustainable cleaning technology for degreasing metal surfaces, addressing the environmental challenges of traditional methods involving surfactants and ultrasound:
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Microbubble Cleaning Efficiency:
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Microbubbles generated via hydrodynamic cavitation achieved oil removal efficiencies of:
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78.5% for carbon-steel surfaces.
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49.8% for stainless-steel surfaces after 15 minutes.
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In contrast, cleaning without microbubbles yielded significantly lower efficiencies (6.5% and 9.9%, respectively).
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Enhanced Performance with Ultrasonication:
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Combining microbubble cleaning with ultrasound increased efficiency to 85.5% in just 3 minutes, compared to 69.0% with ultrasonic cleaning alone.
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Mechanism of Cleaning:
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Fluorescence analysis revealed that microbubbles lift oil contaminants by attaching to the oil, which then floats to the surface for removal.
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This process minimizes emulsified oil in wastewater, allowing easier oil separation and water recycling.
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Environmental Benefits:
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The reduced production of wastewater and the ability to recycle cleaning water make this technology an eco-friendly alternative for degreasing metal surfaces.
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Conclusion:
Microbubble cleaning technology enhances cleaning efficiency, especially when combined with ultrasonication, while significantly reducing wastewater production. This innovative method offers a greener, more sustainable solution for industrial degreasing processes.
Background:
Enterococcus faecalis (E. faecalis) is a common bacterium associated with root canal treatment failure. This study investigates the disinfection and biofilm removal effectiveness of ultrasonic-mediated cold plasma-loaded microbubbles (PMBs) on 7-day-old E. faecalis biofilms, along with their mechanical safety and underlying mechanisms.
Methods:
PMBs were fabricated using a modified emulsification process. Reactive species, nitric oxide (NO) and hydrogen peroxide (H2O2), were analyzed. E. faecalis biofilms grown on human tooth disks were treated with PBS, 2.5% NaOCl, 2% CHX, and varying PMB concentrations (10⁸ mL⁻¹, 10⁷ mL⁻¹). Disinfection and elimination effects were assessed using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Dentin's microhardness and roughness post-treatment were also evaluated.
Results:
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NO and H2O2 concentrations in PMBs increased by 39.99% and 50.97%, respectively, after ultrasound treatment (p < 0.05).
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CLSM and SEM results showed PMBs with ultrasound effectively removed bacteria and biofilm, particularly within dentin tubules.
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2.5% NaOCl exhibited strong effects on surface biofilm but limited efficacy in dentin tubules.
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2% CHX demonstrated significant disinfection capabilities.
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Biosafety tests revealed no significant changes in dentin microhardness or roughness after PMB treatment (p > 0.05).
Conclusion:
Ultrasonic-mediated PMBs provide effective disinfection and biofilm removal, particularly in dentin tubules, with no adverse effects on the mechanical properties of dentin.
The unique characteristics of micro-/nano-bubbles, including their large specific surface area and high Zeta potential, enable efficient adhesion and removal of contaminants, even from complex porous structures typical of 3D-printed products. These bubbles exhibit spontaneous surface charging, which attracts contaminant particles, and their rupture generates tiny jets and shock waves. These mechanical actions are significantly amplified when combined with ultrasound, creating a synergistic effect that efficiently removes sticky or embedded contaminants.
Ultrasonic waves complement the action of nanobubbles by inducing their rapid collapse and rupture. This generates intense localized forces capable of dislodging contaminants that traditional cleaning methods fail to remove. The study highlights that the coupling of these technologies not only enhances the cleaning efficiency but also provides an environmentally friendly alternative to conventional cleaning approaches, which often rely on harsh chemicals. This combined method is particularly effective for cleaning the intricate internal surfaces and fine structures of 3D-printed polymeric products, where contaminants such as oils and microparticles tend to accumulate.
The findings underscore the potential of nanobubble and ultrasonic technology as a powerful, green cleaning solution for 3D-printed items, addressing the limitations of conventional methods and expanding applications in various fields, including clinical medicine, industrial manufacturing, and consumer products. This coupled approach ensures thorough cleaning without damaging delicate structures, making it a promising tool for maintaining the quality and functionality of advanced 3D-printed components.
This study highlights the enhanced efficacy of ultrasonic cleaning when combined with nanobubbles for removing foodborne pathogens, such as Escherichia coli O157
and Listeria innocua, from spinach surfaces and wash water. While neither nanobubbles nor ultrasound alone achieved significant bacterial reduction in suspension, their combination demonstrated a synergistic effect, achieving over 6 log cfu/mL reduction after 15 minutes and 7 log cfu/mL reduction after 10 minutes for L. innocua and E. coli, respectively. On spinach surfaces, nanobubbles with ultrasound removed more than 2 and 4 log cfu/cm² of L. innocua and E. coli, significantly outperforming ultrasound alone, which only reduced 0.5 and 1 log cfu/cm², respectively.
Nanobubbles enhance bacterial detachment and disrupt biofilms, while ultrasonic waves amplify their cleaning action through cavitation and mechanical force. The study underscores the potential of combining nanobubbles and ultrasound as an effective, chemical-reducing strategy for fresh produce sanitation, though adding food-grade surfactants showed minimal additional benefits. This method offers a promising green approach to improve food safety by addressing the challenges of bacterial adhesion on complex produce surfaces.
The Influence of Nanobubble Size and Stability on Ultrasound Enhanced Drug Delivery
This study underscores the importance of lipid-shelled nanobubbles (NBs) as dual diagnostic and therapeutic agents, with a focus on their potential for enhanced localized delivery in cancer treatment.
Unlike larger microbubbles, the submicron size of NBs (<1 μm) allows for better penetration and accumulation in tumor interstitial spaces, potentially improving diagnostic imaging and therapeutic efficacy. However, accurate characterization of NBs poses a challenge due to their small size, which limits conventional microscopy and light scattering techniques.
A novel approach using nanoparticle tracking analysis was employed to differentiate between NBs and liposomes in terms of optical properties and size distribution. This method was used to study three NB populations of varying sizes, enabling the evaluation of their stability and ultrasound-enhanced delivery potential. Experimental results, including confocal fluorescence microscopy of colorectal cancer cells, revealed that the expected trend of larger NBs outperforming smaller ones was not observed. Instead, stability emerged as a critical factor influencing
The study explores the use of nanobubbles (NBs) and ultrasonication (US) as a novel, green method for extracting phytochemicals from Camellia oleifera shells (COSs), a by-product often discarded as agricultural waste. By leveraging the unique properties of NBs—such as high surface area, internal pressure, and stability enhanced by rhamnolipid biosurfactants—this method optimizes extraction efficiency while minimizing environmental impact.
Key findings include:
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The NBs produced were 100 nm in size with a surface tension of 35.26 mN/m−1.
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Using Box–Behnken design, the study optimized ultrasonic power, duration, and surfactant concentration for maximum phytochemical yield.
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The combination of NBs and US achieved significantly higher yields of total phenolics (34.42 mg GAE/g DW) and flavonoids (23.36 mg RE/g DW) compared to conventional solvent methods.
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In vitro antioxidant activity was enhanced with the NBs-US method.
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Morphological and microstructural changes in COSs under this process were analyzed, offering insights into the extraction mechanism.
This approach not only maximizes the value of agricultural waste but also aligns with sustainable practices by reducing reliance on organic solvents and minimizing environmental costs. It highlights a scalable method for agro and food waste valorization.
Nanobubbles, when combined with ultrasound technology, represent a groundbreaking advancement in efficiency, precision, and sustainability across various industries.
These microscopic gas-filled bubbles exhibit unique physical and chemical properties that, when paired with ultrasound, amplify their effectiveness in applications ranging from cleaning to medical therapies.
Key Advantages:
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Enhanced Cleaning Power – The synergy of nanobubbles and ultrasound generates high-energy microjets and acoustic cavitation, effectively breaking down biofilms, debris, and contaminants on surfaces without the need for harsh chemicals.
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Improved Oxygenation and Delivery – In medical and agricultural applications, nanobubbles enriched with oxygen, coupled with ultrasound, enable targeted and rapid delivery, enhancing therapeutic outcomes and soil health.
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Eco-Friendly Efficiency – This combination reduces the reliance on harmful chemicals and minimizes water and energy use, supporting sustainable practices in water treatment, food processing, and industrial cleaning.
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Precision and Control – Ultrasound enhances the distribution and activity of nanobubbles, providing a level of control that ensures optimal performance in critical processes such as semiconductor cleaning or medical treatments.
By combining the powerful dynamics of ultrasound with the innovative properties of nanobubbles, industries can achieve unparalleled results, paving the way for more efficient, sustainable, and high-performance solutions.
This study demonstrates an innovative in-situ sediment remediation method utilizing ultrasound and ozone nanobubbles to tackle both organic and inorganic contaminants.
The technique combines ultrasound to desorb contaminants, ozone to oxidize chemicals, and nanobubbles to enhance ozone's availability, ensuring effective pollutant removal.
Key Highlights:
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Dual Contaminant Removal: Effective for both organic (p-terphenyl) and inorganic (chromium) pollutants in sediments.
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Oxidation and Removal: Insoluble Cr(III) is oxidized to soluble Cr(VI), allowing its removal via nanofiltration, while p-terphenyl is degraded through oxidation and ultrasound effects.
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Efficiency Achieved:
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Chromium: Up to 87.2% removal at lower concentrations with optimized treatment cycles.
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P-terphenyl: Maximum removal of 82.7% at high energy densities (127.2 J/ml).
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Process Insights:
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Removal efficiency depends on factors like oxidizing agent availability, ultrasound energy density, and treatment cycles.
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Chromium removal benefits from repeated washing and oxidation, while p-terphenyl degradation relies on oxidation and ultrasound-induced pyrolysis.
This method showcases a promising solution for mitigating environmental and health risks posed by sediment contamination, offering high efficiency for diverse pollutant types.
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Low frequency nanobubble-enhanced ultrasound mechanotherapy for noninvasive cancer surgery
Nanobubbles, when coupled with low-energy ultrasound at 80 kHz (below their resonance frequency), offer a promising, noninvasive cancer therapy. In experiments, nanobubbles act as therapeutic agents that produce strong mechanical effects in tumors after systemic injection, achieving the following:
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Mechanics of Nanobubble Destruction:
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At 80 kHz insonation, nanobubbles implode at lower acoustic pressures compared to microbubbles, complying with safety regulations (mechanical index below 1.9).
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Complete destruction of nanobubbles required a mechanical index of 1.2 at 80 kHz vs. 2.6 at 250 kHz.
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Tumor Ablation Results:
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In vitro studies on breast cancer cells reduced cell viability to 17.3%.
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In vivo studies in a breast cancer mouse model showed effective tumor ablation and tissue fractionation using low frequency insonation.
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Therapeutic Advantages:
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Safe, noninvasive, and low-energy treatment method.
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Effective delivery and accumulation of nanobubbles in tumor tissues, enabling mechanical tumor destruction.
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This approach presents a novel theranostic platform for cancer treatment, combining diagnostic imaging and targeted mechanical therapy.
Summary:
Spinal cord injuries (SCIs) often lead to severe disability, with existing treatments providing limited functional recovery. This study investigates the potential of ultrasound (US)-mediated destruction of poly(lactic-co-glycolic acid) (PLGA) nanobubbles (NBs) carrying nerve growth factor (NGF) for promoting nerve regeneration in a rat SCI model. Key findings include:
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Methods:
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Rats were divided into four groups: normal saline (NS), NGF and NBs, NGF and US, and NGF/PLGA NBs with US.
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Histological analysis, neuron viability, apoptosis, NGF expression, and neural function were evaluated.
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Results:
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US-mediated destruction of NGF/PLGA NBs significantly increased NGF gene and protein expression.
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Treatment reduced histological injury, minimized neuron loss, and inhibited neuronal apoptosis.
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Functional recovery was improved, with higher Basso, Beattie, and Bresnahan (BBB) scores in treated rats.
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Conclusion:
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The combination of US irradiation and NGF/PLGA NBs effectively transfects the NGF gene into target tissues, promoting nerve regeneration and functional recovery.
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This approach demonstrates great potential as a noninvasive nanomedicine-based treatment for SCI and other conditions.
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