The Groundbreaking Study from USP
In a remarkable advancement from Brazil's leading research institution, scientists at the University of São Paulo (USP) have demonstrated that high-frequency ultrasound can physically dismantle the structure of enveloped respiratory viruses, offering a novel, non-chemical approach to combating infections like COVID-19 and influenza. Published in Scientific Reports on February 13, 2026, the study reveals how ultrasound waves at diagnostic frequencies—ranging from 3 to 20 MHz—trigger resonance in viral envelopes, leading to fragmentation and loss of infectivity without harming human cells. This breakthrough builds on earlier work by the same team, positioning USP as a frontrunner in physics-based antiviral strategies.
The research, led by Flavio P. Veras from the São Carlos Institute of Physics (IFSC-USP), coordinator Prof. Odemir M. Bruno (IFSC-USP), and collaborators from USP Ribeirão Preto and São Paulo State University (UNESP), tested the method on SARS-CoV-2 variants (wild-type, Gamma P.1, Delta) and Influenza A (H1N1). The findings suggest potential applications for a broad spectrum of spherical enveloped viruses prevalent in Brazil, where respiratory illnesses remain a significant public health challenge.
How Acoustic Resonance Targets Viral Structures
Traditional antiviral treatments rely on chemical agents that target specific viral proteins, often leading to resistance through mutations. In contrast, this ultrasound method exploits physical properties of the virus. Enveloped viruses like SARS-CoV-2 and H1N1 have lipid membranes surrounding their genetic material, with diameters around 100-130 nm. When exposed to ultrasound waves matching their resonant frequency, these particles vibrate intensely due to acoustic impedance mismatch, causing envelope rupture and internal disruption.
The process, termed acoustic resonance, differs from cavitation (bubble formation at lower kHz frequencies) or thermal effects. Clinical ultrasound devices maintained mechanical index (MI) values of 0.4-1.0, ensuring no heating (temperature stable below 42°C) or pH changes. Dynamic light scattering (DLS) showed untreated SARS-CoV-2 peaking at 107 nm shifting to smaller fragments (1.5 nm, 4.9 nm peaks), while H1N1 signals vanished entirely.
Scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed morphological changes: irregular surfaces, collapsed envelopes, and 'popcorn-like' fragmentation in treated virions. This mechanical disruption renders the viruses noninfectious, as verified by reduced TCID50 titers and lower viral antigens in cell cultures.
Experimental Methods: Rigorous In Vitro Testing
The team propagated viruses in Vero E6 cells for SARS-CoV-2 (BSL-3) and MDCK cells for H1N1 (BSL-2), standardizing titers via TCID50. Exposure used commercial systems like Esaote MyLab 60 and Philips Envisor HD at 3-18 MHz for 1-30 minutes. Post-exposure, structural integrity was assessed via DLS, SEM, AFM on UV-inactivated samples to ensure safety.
- Virus Preparation: High-titer stocks from clinical isolates.
- Ultrasound Parameters: Frequencies optimized around 7.5 MHz for maximum effect; MI <1.0 to avoid cavitation.
- Infectivity Assays: Vero E6 cells infected with treated virus, monitored via immunofluorescence (spike protein, dsRNA) and confocal microscopy.
- Controls: No temperature/pH shifts; kHz cavitation tests for comparison showed nonspecific damage.
Statistical analysis employed ANOVA with post-hoc tests (p < 0.05), confirming reproducibility across experiments.
Key Findings: Dramatic Reduction in Viral Infectivity
The study reported significant outcomes: SARS-CoV-2 wild-type infectivity dropped markedly at 7.5 MHz, with cumulative effects over time. Variants Gamma and Delta showed partial resistance, highlighting the need for frequency tuning. H1N1 was completely degraded, undetectable by DLS post-treatment.
In cell infections, ultrasound-treated viruses led to fewer infected cells and lower replication, evidenced by diminished spike protein and dsRNA signals. Polydispersity index rose, indicating heterogeneity from fragments. Optimal exposure: 5-10 minutes at resonance frequencies.
Safety and Selectivity: Sparing Human Cells
A critical advantage is selectivity. Human cells, larger (10-100 μm) with different acoustic properties, remain unaffected at these MHz frequencies. No cytopathic effects in mock-infected controls, and viral reduction persisted in infectivity assays. This positions ultrasound as a safe adjuvant therapy, potentially deliverable via portable devices or inhalers tuned to patient airways.Read the full study here.
Prof. Bruno emphasized: “Ultrasound has been safe for imaging for decades; repurposing it therapeutically introduces physics to antiviral medicine.”
Photo by Francesco Ungaro on Unsplash
The Research Team at USP
Flavio P. Veras, PhD candidate at IFSC-USP, spearheaded experiments, noting: “Physical stimuli like ultrasound offer mutation-resistant alternatives.” Prof. Odemir M. Bruno, expert in computational physics, coordinated modeling. Collaborators include Eurico Arruda (Virology Center, FMRP-USP) and Fernando Q. Cunha (Inflammatory Diseases Center, FMRP-USP), bridging physics and biomedicine. Funding from FAPESP (e.g., grants 2020/07645-0, 2023/07241-5) and CNPq supported BSL facilities and equipment.
IFSC-USP's interdisciplinary groups in biophysics and structural biology facilitated this fusion of acoustics, virology, and imaging.
Building on Pioneering USP Work
This 2026 study extends 2022-2023 in vitro SARS-CoV-2 experiments, where 5-10 MHz resonance inactivated spike proteins. Theoretical models in Brazilian Journal of Physics validated resonance in spherical scatterers.Explore the model. Ongoing FAPESP-funded projects target arboviruses like dengue.
Brazil's Respiratory Virus Burden
Brazil faces seasonal surges: 2025 saw influenza SARI deaths up 127% in São Paulo, RSV lethality 1.28% in infants under 1, COVID-19 persisting with 26.5% lethality in SARI cases. With 14,816 SARI cases reported, including co-infections, innovative therapies are urgent. USP's approach could reduce hospitalization rates, especially in underserved regions.
Ministry of Health surveillance highlights influenza A dominance, underscoring need for broad-spectrum tools.
Path to Clinical Translation
Next steps: in vivo animal models to assess airway delivery, optimal dosing, and variant efficacy. Portable transducers or nebulized ultrasound eyed for home use. Prof. Veras envisions integration with ventilators for ICU patients. Challenges include penetration depth and strain-specific tuning, but safety profile bodes well for trials.
- Preclinical: Hamster/rat infection models.
- Clinical Phase I: Safety in healthy volunteers.
- Devices: Frequency-tunable probes for personalization.
USP's Legacy in Higher Education and Research
USP, Brazil's top university, hosts world-class facilities like IFSC-USP for physics-biomed convergence. FAPESP funding amplifies such innovations, fostering collaborations across campuses. This positions USP researchers for global impact, attracting talent and jobs in biomedical engineering.
Photo by Raymart Arniño on Unsplash
Global and Local Implications
Beyond Brazil, the method targets RSV, H5N1, herpesviruses. In Brazil, it addresses disparities in antiviral access, potentially lowering economic burden from SARI (e.g., billions in healthcare costs). As climate change intensifies outbreaks, physics-based tools offer resilient solutions.USP portal coverage.
Prospects include combination therapies, enhancing vaccines or antivirals.
Future Outlook and Opportunities
USP's work heralds a paradigm shift: physics combating biology. With FAPESP support, expect rapid progress toward prototypes. For aspiring researchers, USP offers vibrant programs in biophysics, virology—explore opportunities via research positions. This innovation underscores Brazil's higher education prowess in addressing global health threats.