Dual-frequency Ultrasound Research Articles

The promise of coupling piezo-catalysis and activated persulfate using dual-frequency ultrasound: A novel synergistic method of natural water disinfection

Piezo-coupled catalysis, which is driven by dual-frequency ultrasound (DFUS) at high frequencies (>100 kHz), has emerged as a promising technique for intensifying the oxidation processes in aqueous media. This study aimed at evaluating the performance of high-frequency DFUS (0.12 + 1.7 MHz) coupled with ZnO microparticles (1 µm) and persulfate (S2O82−) for disinfection of filtered natural surface water, spiked with E. coli and E. faecalis, as well as unfiltered natural water with indigenous microflora. Despite the longer treatment times required (as compared to deionized water), this hybrid system provided the fastest inactivation, exhibiting a synergy between DFUS+ZnO and DFUS+S2O82− processes and a high energy-efficiency (231.5 and 91.3 CFU/J for E. coli and E. faecalis, respectively). The obtained results revealed the feasibility of DFUS-driven piezo-coupled catalysis using persulfate for advanced water disinfection.

The effect of dual-frequency ultrasound on synergistic Sonochemical oxidation to degrade aflatoxin B1

This study investigated the degradation of aflatoxin B1 (AFB1) in food by using dual-frequency ultrasound (DFUS) and the effects of sonochemical oxidation on the efficacy. It was found that the degradation of AFB1 by bath ultrasound (BU), probe ultrasound (PU), and DFUS were all consistent with first-order kinetics. The use of DFUS significantly increased the AFB1 degradation to 91.3%, and compared with BU and PU, it increased by about 177.0% and 61.5% after 30 min treatment. DFUS could generate a synergistic effect to accelerate the generation of free radicals, which promoted sonochemical oxidation to degrade AFB1. It could be speculated that hydroxyl radical (·OH) probably acted a dominant part in the AFB1 degradation by DFUS, and the hydrogen atoms (·H) might also are contributed. These results indicated that DFUS was an effective method of AFB1 degradation.

Tetracycline degradation by dual-frequency ultrasound combined with peroxymonosulfate

Tetracycline has received a great deal of interest for the harmful effects of substance abuse on ecosystems and humanity. The effects of different processes on the degradation of tetracycline were compared, with dual-frequency ultrasound (DFUS) in combination with peroxymonosulfate (PMS) being the most effective for the tetracycline degradation. Free radical scavenging experiments showed that O2∙-,SO4∙- and •OH were the main reactive radicals in the degradation of tetracycline. According to the major intermediates of tetracycline degradation identified, three possible degradation pathways were proposed, which are of significance for translational studies of tetracycline degradation. Notably, these intermediates were found to be significantly less toxicity. The number of active bubbles in the degradation vessel was calculated using a semi-empirical formula, and a higher value of 1.44 × 108 L-1s−1 of bubbles was obtained when using dual-frequency ultrasound at 20 kHz (210 W/L) and 80 kHz (85.4 W/L). Therefore, compared to 20 kHz, although the yield of strong oxidizing substances from individual active bubbles decreased slightly, a significant increment of the number of active bubbles still resulted in a higher synergistic effect, and the combination of DFUS and PMS should be effective in promoting the generation of reactive free radicals and mass transfer processes within the degradation vessel, which provides a method for efficient removal of tetracycline from wastewater.

Dual-Frequency Impedance Matching Network Design Using Genetic Algorithm for Power Ultrasound Transducer.

Dual-frequency ultrasounds have demonstrated significant potential in augmenting thermal ablation efficiency for tumor treatment. Ensuring proper impedance matching between the dual-frequency transducer and the power amplifier system is imperative for equipment safety. This paper introduces a novel dual-frequency impedance matching network utilizing L-shaped topology and employing a genetic algorithm to compute component values. Implementation involved an adjustable capacitor and inductor network to achieve dual-frequency matching. Subsequently, the acoustic parameters of the dual-frequency HIFU transducer were evaluated before and after matching, and the effects of ultrasound thermal ablation with and without matching were compared. The proposed dual-frequency impedance matching system effectively reduced the standing wave ratio at the two resonance points while enhancing transmission efficiency. Thermal ablation experiments with matching circuits showed improved temperature rise efficiencies at both frequencies, resulting in an expanded ablation zone. The dual-frequency impedance matching method significantly enhances the transmission efficiency of the dual-frequency ultrasound system at two operational frequencies, thereby ensuring equipment safety. It holds promising prospects for application in dual-frequency ultrasound treatment.

Dual-Frequency Ultrasound Assisted Thrombolysis in Interventional Therapy of Deep Vein Thrombosis.

Deep vein thrombosis (DVT) is one of the main causes of disability and death worldwide. Currently, the treatment of DVT still needs a long time and faces a high risk of major bleeding. It is necessary to find a rapid and safe method for the therapy of DVT. Here, a dual-frequency ultrasound assisted thrombolysis (DF-UAT) is reported for the interventional treatment of DVT. A series of piezoelectric elements are placed in an interventional catheter to emit ultrasound waves with two independent frequencies in turn. The low-frequency ultrasound drives the drug-loaded droplets into the thrombus, while the high-frequency ultrasound causes the cavitation of the droplets in the thrombus. With the joint effect of the enhanced drug diffusion and the cavitation under the dual-frequency ultrasound, the thrombolytic efficacy can be improved. In a proof-of-concept experiment performed with living sheep, the recanalization of the iliac vein is realized in 15min using the DF-UAT technology. Therefore, the DF-UAT can be one of the most promising methods in the interventional treatment of DVT.

Dual-frequency piezoelectric micromachined ultrasound transducer based on polarization switching in ferroelectric thin films

Due to its additional frequency response, dual-frequency ultrasound has advantages over conventional ultrasound, which operates at a specific frequency band. Moreover, a tunable frequency from a single transducer enables sonographers to achieve ultrasound images with a large detection area and high resolution. This facilitates the availability of more advanced techniques that simultaneously require low- and high-frequency ultrasounds, such as harmonic imaging and image-guided therapy. In this study, we present a novel method for dual-frequency ultrasound generation from a ferroelectric piezoelectric micromachined ultrasound transducer (PMUT). Uniformly designed transducer arrays can be used for both deep low-resolution imaging and shallow high-resolution imaging. To switch the ultrasound frequency, the only requirement is to tune a DC bias to control the polarization state of the ferroelectric film. Flextensional vibration of the PMUT membrane strongly depends on the polarization state, producing low- and high-frequency ultrasounds from a single excitation frequency. This strategy for dual-frequency ultrasounds meets the requirement for either multielectrode configurations or heterodesigned elements, which are integrated into an array. Consequently, this technique significantly reduces the design complexity of transducer arrays and their associated driving circuits.

Synergistic Piezo-Catalytic Inactivation of Bacteria by Dual-Frequency Ultrasound (120 + 1700 kHz) Using Persulfate and ZnO Nano- and Microparticles

Dual-frequency ultrasound (DFUS) coupled with sonocatalysts has emerged to be an advanced tool for antimicrobial applications in medicine but remains scarcely studied for water disinfection. In the present work, we first integrated high-frequency DFUS (120 + 1700 kHz), persulfate (S2O82−) and ZnO nano- (50 nm) and microparticles (1 μm) for eradicating Escherichia coli and Enterococcus faecalis in synthetic water. For E. coli, the efficiency of DFUS-based processes can be ranked as follows: DFUS < DFUS/ZnO < DFUS/S2O82− < DFUS/ZnO/S2O82−. A similar efficiency of the DFUS/S2O82− and DFUS/ZnO/S2O82− processes was found for more resistant E. faecalis. In the absence of persulfate, the performance of 1 μm ZnO was higher than that observed with 50 nm for inactivating E. coli via the DFUS/ZnO and 1700 kHz/ZnO processes. A synergy of DFUS in terms of 5-log (total) reduction was found in the S2O82−/ZnO-based systems, being higher for E. faecalis (synergistic coefficient = 1.8–3.0). The synergistic effect was proposed to be driven by the boosted generation of reactive oxygen species and sonoporation. This study opens prospects for the development of novel DFUS-based piezo-catalytic systems for efficient water disinfection.

Combined use of microbubbles of various sizes and single-transducer dual-frequency ultrasound for safe and efficient inner ear drug delivery.

We have previously applied ultrasound (US) with microbubbles (MBs) to enhance inner ear drug delivery, with most experiments conducted using single-frequency, high-power density US, and multiple treatments. In the present study, the treatment efficacy was enhanced and safety concerns were addressed using a combination of low-power-density, single-transducer, dual-frequency US (I SPTA= 213 mW/cm2) and MBs of different sizes coated with insulin-like growth factor 1 (IGF-1). This study is the first to investigate the drug-coating capacity of human serum albumin (HSA) MBs of different particle sizes and their drug delivery efficiency. The concentration of HSA was adjusted to produce different MB sizes. The drug-coating efficiency was significantly higher for large-sized MBs than for smaller MBs. In vitro Franz diffusion experiments showed that the combination of dual-frequency US and large MB size delivered the most IGF-1 (24.3± 0.47 ng/cm2) to the receptor side at the second hour of treatment. In an in vivo guinea pig experiment, the efficiency of IGF-1 delivery into the inner ear was 15.9 times greater in animals treated with the combination of dual-frequency US and large MBs (D-USMB) than in control animals treated with round window soaking (RWS). The IGF-1 delivery efficiency was 10.15 times greater with the combination of single-frequency US and large size MBs (S-USMB) than with RWS. Confocal microscopy of the cochlea showed a stronger distribution of IGF-1 in the basal turn in the D-USMB and S-USMB groups than in the RWS group. In the second and third turns, the D-USMB group showed the greatest IGF-1 distribution. Hearing assessments revealed no significant differences among the D-USMB, S-USMB, and RWS groups. In conclusion, the combination of single-transducer dual-frequency US and suitably sized MBs can significantly reduce US power density while enhancing the delivery of large molecular weight drugs, such as IGF-1, to the inner ear.

Dual-Frequency Ultrasonic Inactivation of Escherichia coli and Enterococcus faecalis Using Persulfate: A Synergistic Effect

Dual-frequency ultrasound (DFUS) has received considerable attention for enhanced inactivation of microbial pathogens for medical treatment, but remains little investigated for water disinfection. This study is focused on inactivation of E. coli and E. faecalis in aqueous solution under dual-frequency ultrasonication at 120 + 1700 kHz using persulfate. Single-frequency ultrasonic inactivation showed the higher efficiency of 1700 kHz, compared to 120 kHz. Under the experimental conditions used, no measurable synergy between two frequencies was observed in the absence of persulfate. A high time-based synergistic effect in terms of total inactivation (5-log) of both bacterial species was achieved by DFUS-activated persulfate with synergistic indices of 1.8–5.0. We assume that this is attributed to increased generation of reactive oxygen species (primarily, sulfate anion (SO4•−) and hydroxyl (•OH) radicals) as a result of enhanced acoustic cavitation. Radical probing and scavenging tests confirmed the generation of radicals and showed a nearly equal contribution of •OH and SO4•−. This method could be an attractive alternative to ultraviolet technology for fast and effective water disinfection.

Gelling Characteristics of Emulsions Prepared with Modified Whey Protein by Multiple-Frequency Divergent Ultrasound at Different Ultrasonic Power and Frequency Mode.

The effect of ultrasonic frequency mode (mono, dual and tri-frequency) and ultrasonic power (0–300 W) on structural properties (intrinsic fluorescence and sulfhydryl content) of whey protein was studied. Emulsions prepared with modified whey protein were used to form the heat-set gels, and the properties of whey protein emulsion gels (WPEG) and their digestion were investigated. The textural and rheological properties of WPEG prepared using whey protein pretreated by mono and dual-frequency ultrasound at the power between 180–240 W were enhanced, while those of WPEG prepared with whey protein pretreated by triple-frequency above the power of 180 W were declined. WPEG prepared using whey protein pretreated by dual-frequency ultrasound (DFU) with the power of 240 W had the highest hardness and storage modulus which were 3.07 and 1.41 times higher than the control. The microstructure of WPEG prepared using DFU pretreated whey protein showed homogeneous and denser networks than those of the control according to the results of confocal laser scanning microscope (CLSM). The modification in the microstructure and properties of the WPEG prepared using DFU pretreated whey protein delayed the protein disintegration during the first 30 min of gastric digestion when compared with control. Whereas the release rate of free amino group of the WPEG prepared using whey protein modified by ultrasonic pretreatment increased during the intestinal phase when compared with that of control. The results indicated that using dual-frequency ultrasound to modify whey protein is more efficient in improving the properties of WPEG, and ultrasonic power should be considered during the application of ultrasound pretreatment in producing protein gels. The fine network of WPEG prepared with whey protein pretreated by ultrasound resulted in better hardness and storage modulus. Partially unfolding of the protein induced by ultrasound pretreatment might make the whey protein more susceptible to the digestive enzyme. Our results could provide new insights for using ultrasound as the potential processing tool on designing specific protein emulsion gels as the delivery system for nutrients.

Effect of mono- and dual frequency power ultrasound assisted enzymolysis on the degree of hydrolysis and ACE inhibitory activity of Stevia protein hydrolysates


 
 
 
 Purpose: To study the effects of ultrasound pretreatment at different frequencies and working modes, including mono frequency ultrasound (MFU) and dual-frequency ultrasound (DFU), on the degree of hydrolysis (DH) and angiotensin-I-converting enzyme (ACE) inhibitory effect of Stevia protein (SP).
 Methods: Protein from Stevia leaves was extracted by water (50 g suspended in 1000 mL). The hydrolysis of stevia protein extract (SPE) was carried out using alcalase at 5 % enzyme substrate (E/S) ratio. A study was then carried out to investigate its microstructure and morphology using scanning electron microscopy (SEM).
 Results: The results showed that ultrasound pretreatment did not increase DH of SP significantly (p > 0.05). However, the highest ACE inhibitory activity of stevia protein hydrolysate was obtained at DFU level (20/50 KHz). Overall, ultrasonic frequency mode had a significant influence on ACE inhibitory activity.
 Conclusion: The frequency selection of ultrasound pretreatment of SP is essential for the preparation of ACE inhibitory peptide.
 
 
 

The Effect of Dual-Frequency Ultrasound on Synergistic Sonochemical Oxidation to Degrade Aflatoxin B1

The Effect of Dual-Frequency Ultrasound on Synergistic Sonochemical Oxidation to Degrade Aflatoxin B1

Phase I trial of acoustic cluster therapy (ACT) with chemotherapy in patients with liver metastases of gastrointestinal origin (ACTIVATE study).

TPS3145 Background: Response to existing chemotherapeutics (chemo) can be limited by exposure, itself limited by systemic toxicity. Interstitial fluid pressure can impede transport of drugs with, in some cases, <5% of systemic chemo penetrating the target tumour. ACT is an innovative platform technology using sonopermeation to induce ultrasound (US) mediated targeting of therapeutic agent of choice by co-administration of an emulsion of microbubble-microdroplet clusters (PS101) for intravenous injection. Dual-frequency US is applied to tumor tissue to concentrate the drug through expansion and oscillation of the clusters, increasing tumoral penetration. Early pre-clinical models of ACT indicate significant increase in uptake of co-administered product at the US targeted site and have demonstrated enhanced efficacy outcomes with co-administered ACT across a range of cancer models. All studies showed significant benefit in disease response and tumour regression/inhibition versus drug alone. The combination of US, microbubbles and chemo has been shown to be feasible in a clinical setting using commercially available equipment with no additional toxicities. This first in human study will primarily investigate the safety and tolerability of PS101 in combination with chemo together with any differential response in ACT-treated versus control lesions to identify the phase 2 recommended dose. Methods: This is an open label non-randomised study with central blinded assessment of tumor response. The study comprises two parts: Part 1, a dose escalation in a 3+3 design followed by dose expansion in Part 2. Patients with advanced solid tumors with liver metastases for whom FOLFOX/FOLFIRI is considered an appropriate treatment option are eligible for Part 1 (n=6-12); two separate cohorts of patients with liver metastases, one with metastatic colorectal cancer eligible for 1L or 2L standard of care (SOC) FOLFOX/FOLFIRI (n=25) and one with metastatic pancreatic ductal adenocarcinoma (n= 6) eligible for SOC gemcitabine-nab-paclitaxel will be treated in Part 2. The starting dose of PS101 is 20 µL/kg with a maximum feasible dose of 40 µL/kg. In Part 1, after sentinel administration of PS101 for PK profiling and toxicity assessment, patients receive PS101 (given as i.v. bolus x 3) in combination with FOLFOX or FOLFIRI and US (to one target lesion) in four q2w cycles. The DLT evaluation period comprises the PK-assessment period plus two cycles of ACT plus chemo. Patients receive a further two cycles of ACT and chemo prior to evaluation of tumor lesions by CT/MRI at the Week 8 timepoint. Assessment is made of the target lesion and the pre-defined control lesions outside of the US field. Part 1 has enrolled 5 patients without DLT, with part 2 expected to start in mid-2021. Clinical trial information: NCT04021277.

The Efficacy and Safety of Dual-Frequency Ultrasound for Improving Skin Hydration and Erythema in Patients with Rosacea and Acne.

Inflammatory skin diseases, such as rosacea and acne, are major causes of facial erythema and accompanying skin barrier dysfunction. Several methods to restore the impaired skin barrier and improve facial erythema, such as medication, radiofrequency, laser, and ultrasound therapy were attempted. This study evaluated the efficacy and safety of dual-frequency ultrasound with impulse mode, for improving skin hydration and erythema in Asian subjects with rosacea and acne. Twenty-six subjects with facial erythema received an ultrasound treatment once per week, for 4 weeks, over both cheeks. The erythema index and transepidermal water loss (TEWL) were measured at each visit. Clinicians assessed the erythema improvement and patients evaluated their satisfaction level. The average decrease in TEWL and erythema index at 6 weeks was 5.37 ± 13.22 g·h−1·m−2 (p = 0.020) and 39.73 ± 44.21 (p = 0.010), respectively. The clinician’s erythema assessment and the subject satisfaction questionnaire score significantly improved at final follow-up (p < 0.001; p = 0.003, respectively). No serious adverse effects were observed during the treatment and follow-up periods. The dual-frequency ultrasound with impulse mode appears to be effective and safe for improving skin hydration and erythema in patients with rosacea and acne.

Enhanced degradation of total petroleum hydrocarbons in real soil by dual-frequency ultrasound-activated persulfate

Ultrasound (US) can be employed to activate persulfate (PS) for degrading total petroleum hydrocarbons (TPH). In this study, to improve the degradation efficiency, PS is combined with dual-frequency US (DFUS) towards synergistic degradation of TPH in real soil. After 180 min, the degradation percentages for DFUS/PS, DFUS, high-frequency US and high-frequency US/PS are around 88.9%, 38.7%, 7.3% and 54.2%, respectively. Additionally, the influence of US power, PS content, slurry pH and temperature, and TPH components on the degradation percentage in the DFUS/PS process are explored. Scanning electron microscopy (SEM) images and the results of specific surface area verify that the DFUS can break the soil aggregates more effectively than the single-frequency US, and thus enhance the TPH desorption and accelerate the oxidant diffusion. Moreover, the investigation of the mechanism is further evaluated through quenching and electron spinning resonance spectrum (ESR) tests. The results indicate that the generation of SO4− and OH in DFUS/PS is ~1.6 times and ~2.5 times as much, respectively, as in high frequency US/PS. The relative contributions to the synergistic TPH degradation in the DFUS/PS system are: SO4− (PS activation via the heat induced by US) > pyrolysis inside the bubbles (hydrophobicity of TPH) > SO4− (PS activation via US cavitation) >OH. Finally, the hypothesis is confirmed via the evaluation of the degradation kinetics, which shows that the combined process of DFUS/PS is not a simple addition of the US and PS, but provides a highly effective process of synergistic degradation.

Low-frequency dual-frequency ultrasound-mediated microbubble cavitation for transdermal minoxidil delivery and hair growth enhancement

Ultrasound (US) has been found to rejuvenate and invigorate the hair follicles, increase the size of hair shafts, and promote new hair growth. Our present study found that dual-frequency US-mediated microbubble (MB) cavitation significantly enhanced minoxidil (Mx) delivery in both in vitro and in vivo models, while increasing the hair growth efficacy compared to single-frequency US sonication. The in vitro experiments showed that cavitation activity was enhanced more significantly during dual-frequency sonication than single-frequency sonication in higher concentration of MBs. The pigskin penetration depth in the group in which dual-frequency US was combined with MBs was 1.54 and 2.86 times greater than for single-frequency US combined with MBs and in the control group, respectively; the corresponding increases in the release rate of Mx at 18 hours in in vitro Franz-diffusion-cell experiments were 24.9% and 43.7%. During 21 days of treatment in C57BL/6J mice experiments, the growth rate at day 11 in the group in which dual-frequency US was combined with MBs increased by 2.07 times compared to single-frequency US combined with MBs. These results indicate that dual-frequency US-mediated MB cavitation can significantly increase both skin permeability and transdermal drug delivery. At the same US power density, hair growth was greater in the group with dual-frequency US plus MBs than in the group with single-frequency US plus MBs, without damaging the skin in mice.

Synergistic degradation of PFAS in water and soil by dual-frequency ultrasonic activated persulfate

Ultrasound (US) can degrade per- and polyfluoroalkyl substances (PFAS) by the cavitation or pyrolysis effect. In this study, we find that the US equipment typically used in a common laboratory, such as 20 kHz and 43 kHz for cleaning or homogenisation, can degrade PFAS, although the process is slow (with approximately 14.6% and 20.1% defluorination after 6 h, respectively). To accelerate the degradation process, a dual-frequency US is combined with persulfate (PS) to synergistically degrade PFAS in water and soil. Typical PFAS including perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS) and 1H, 1H, 2H, 2H-perfluorooctanesulfonic acid (6:2 FTS) are used to evaluate the degradation performance of dual-frequency US/PS in water. After 6 h of degradation, the defluorination percentage is, from highest to lowest, PFOA (100 ± 1.2%) > 6:2 FTS (86.9 ± 0.9%) > PFOS (46.5 ± 1.0%). Interestingly, the dual-frequency US/PS process can also efficiently degrade PFAS in the contaminated soil, with a 62–71% degradation of 14 PFAS (28 is the maximum number of PFAS that can be quantitatively monitored), representing an encouraging progress. Finally, the degradation pathways and kinetics of PFOA are studied by monitoring the degradation intermediates, and by indicating the combination of the dual-frequency US/PS is not simply addition with each other, but with a synergistic effect of degradation.

Application of Dual-Frequency Ultrasound for Treating the Ulcerative Necrobiosis Lipoidica

Application of Dual-Frequency Ultrasound for Treating the Ulcerative Necrobiosis Lipoidica

Combination of thermal and dual‐frequency sonication processes for optimum microbiological and antioxidant properties in cherry tomato

Cherry tomato fruits were treated with three dual-frequency ultrasound (US) at different temperature and time. The three treatment variables, that is, dual-frequency US, temperature, and time were optimized with the aid of response surface methodology (RSM). About 20/40 kHz, 52°C, and 6 min were the optimum condition obtained for total bacteria count (TBC, 1.08 log cfu/g), firmness (15.90 N), and total phenolic content (TPC, 34.34 mg GAE/100 g). All the linear relations of the treatment variables showed a significantly negative and positive effect on the TBC and TPC, respectively, while positive significant effects were obtained for some of the relations of the firmness. Hence dual-frequency sonication is effective for microbial safety and maintaining the quality of cherry tomato. Also, RSM was found to be a useful tool in setting and optimizing the variables responsible for sonication treatment. Practical applications Thermosonication (ultrasonication and heat) has been applied toward improving the microbial safety and nutritional quality of vegetables and fruit. However, factors such as power, frequency, time, temperature, etc. determine the efficiency of its operation. Controlling these factors is difficult and therefore requires a robust and efficient optimization tool in determining their effects (individual and interactions) on food during treatment. In this study, response surface methodology provides the solution in settling and optimizing the variables for the sonication treatment. Besides, the remarkable result obtained in this work offers an alternative to the combined use of ultrasound and chemical in food industries.

Granuloma Formation, a Rare Complication after PDO Threads Lifting, and Adjuvant Treatment Using Dual-Frequency Ultrasound (LDM®-MED)

Granuloma Formation, a Rare Complication after PDO Threads Lifting, and Adjuvant Treatment Using Dual-Frequency Ultrasound (LDM^®-MED)