Fundamentals to clinical and commercial translation.

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Our group creates and employs novel engineering and fabrication approaches to overcome longstanding problems, mostly in medicine. We use acoustofluidics, micro/nanofabrication methods, and our discoveries in new fundamental physical phenomena to make way towards applications.

Please see below about our recent research, and our team, facilities, funding, and teaching activities.

We're happy to collaborate with academic and industrial colleagues, and are fortunate to have among the best medical, fabrication, and testing facilities in the world. We also host faculty, students, and industry employees. Gifts in support of our research work may be provided here.

We are looking for motivated PhD student and postdoctoral applicants with thorough training in fluid mechanics, bioengineering, and MEMS/NEMS device fabrication.


Identification of strong turbulence in acoustically-driven capillary waves and the mechanism responsible for them

In a series of papers we show that capillary waves generated upon the surface of fluid interfaces by ~7 MHz to 50 MHz acoustic waves is strongly turbulent, generated by the formation and subsequent changes of the acoustic standing wave in the fluid cavity on the hydrodynamic (slow) time scale, and that with certain power levels weak, intermediate, discrete, and strong wave turbulence appears. Atomization appears at a power level well beyond what is needed to produce strong turbulence, indicating that Faraday waves and parametric turbulence are not responsible for atomization.

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Explaining acoustic streaming

Acoustic streaming is a key phenomena underpinning many of the research works pursued by this laboratory and by other groups interested in ways to drive fluids in microfluidic and nanofluidic systems: Acoustofluidics. Following on from our earlier discovery of acoustogeometric streaming (PRL 126 164502 (2021)) which is uniquely powerful at the nano-scale, we examine the analysis of acoustic streaming in two new papers, one showing how to analyze transient acoustic streaming properly (Phys Rev E 106 045101 2022), and another showing how to handle traditional steady-state acoustic streaming (JFM 975(A4) 2023). These replace classic analysis methods from Nyborg, Rayleigh, Eckart, and Westervelt.

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The mechanisms of sonogenetics

In a recent series of papers produced as a collaboration with the Salk Institute of Biological Sciences, we have made advances toward understanding the reasons behind ultrasound’s interactions with neurons (Advanced Science 2021), microscale devices to provide ultrasound transmission into the brains of mice (Advanced NanoBioMed Research 2022), and the use of hsTRPA1 as a mechanosensitive ion channel suitable for this purpose (Nature Communications 2022). This work is now featured in a new company, SonoBac.

Rapidly changing magnetic fields induces plasma leaks in cancerous brain tumor cells but not healthy cells

The glycocalyx of lung cancer cells might play a role in mediating plasma membrane leak by low-frequency pulsed magnetic fields (Lf-PMF) generated on a low-energy solenoid platform. In testing glioblastoma and neuroblastoma cells known to overexpress glycoproteins rich in modifications by the anionic glycan sialic acid (Sia), exposure of brain tumor cells on the same platform to a pulse train that included a 5 min 50Hz Lf-PMF (dB/dt 2 T/s at 10 ms pulse widths) induced a very modest but significant protease leak above that of control nonex- posed cells (with modest but significant reductions in long-term tumor cell viability after the 5 min exposure). Appearing in the Biophysical Journal (Cell):

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Recent publications

1. ​A. Vasan, U. Magaram, J. Patel, J. Friend, and S. Chalasani. Integrating ultrasound-induced neural activity modulation with fiber photometry. *Frontiers in Acoustics*, **1** 2023.
1. O. Dubrovski, J. Friend, and O. Manor. Theory of acoustic streaming for arbitrary Reynolds number flow. *Journal of Fluid Mechanics*, **975***(A4):1-22, 2023.
1. S. C. Johns, P. Gupta, Y.-H. Lee, J. Friend, and M. M. Fuster. Glycocalyx transduces membrane leak in brain tumor cells exposed to sharp magnetic pulsing. *Biophysical Journal*, **122**:4425-4439, 2023
1. .J. Friend. Acoustofluidics. *Frontiers in Acoustics*, **1** 2023.
1. ​J. Orosco and J. Friend. Identification of weakly to strongly-turbulent three-wave processes in a micro-scale system. *Chaos, Solitons & Fractals*, **172**(113615):1-7, 2023.
1. ​S. Zhang, J. Orosco, and J. Friend. Onset of visible capillary waves from high-frequency acoustic excitation. *Langmuir*, **39**(10):3699-3709, 2023.
1. ​A. Horesh, W. Connacher, and J. Friend. Acoustothermal phase change and acoustically driven atomization for cold liquid microthrusters. *Applied Physics Letters*, **122**(014104):1-7, 2023.
1. ​Y. Zhou, N. Zhang, D. J. Bisharat, R. J. Davis, Z. Zhang, J. Friend, P. R. Bandaru, and D. F. Sievenpiper. On-chip unidirectional waveguiding for surface acoustic waves along a defect line in a triangular lattice. *Physical Review Applied*, **19**(2)2023.
1. A. Huang, H. Liu, P. Liu, and J. Friend. Overcoming the intrinsic limitations of fast charging lithium ion batteries using integrated acoustic streaming. *Advanced Energy and Sustainability Research*, 202200112: 1-10, 2022.
1. ​J. Orosco and J. Friend. Modeling fast acoustic streaming: steady-state and transient flow solutions. *Physical Review E*, **106**(045101):1-17, 2022.
1. ​C. Imashiro, J. Mei, J. Friend, and K. Takemura. Quantifying cell adhesion through forces generated by acoustic streaming. *Ultrasonics Sonochemistry*, **90**(106204):1-8, 2022.
1. ​M. Li, J. Mei, J. Friend, and J. Bae. Acousto-photolithography for programmable shape deformation of composite hydrogel sheets. *Small* (2204288):1-10, 2022.
1. ​J. Mei, A. Vasan, U. Magaram, K. Takemura, S. H. Chalasani, and J. Friend. Well-free agglomeration and on-demand three-dimensional cell cluster formation using guided surface acoustic waves through a couplant layer. *Biomedical Microdevices*, **24**(18):1-13, 2022.
1. ​J. Bravo, A. R. Wali, B. R. Hirshman, T. Gopesh, J. A. Steinberg, B. Yan, J. S. Pannell, A. Norbash, J. Friend, A. A. Khalessi, and D. Santiago-Dieppa. Robotics and artificial intelligence in endovascular neurosurgery. *Cureus*, **14**(3):e23662, 2022.
1. ​J. Rufo, F. Cai, J. Friend, M. Wiklund, and T. Huang. Acoustofluidics for biomedical applications. *Nature Reviews Primers*, **2**(30):1-21, 2022.
1. ​M. Duque, C. Lee-Kubli, Y. Tufail, U. Magaram, J. M. Lopez, E. Edsinger, A. Vasan, R. Shiao, C. Weiss, J. Friend, and S. H. Chalasani. Sonogenetic control of mammalian cells using exogenous transient receptor potential a1 channels. *Nature Communications*, **13**(600):1-17, 2022.
1. ​A. Vasan, F. Allein, M. Duque, U. Magaram, N. Boechler, S. H. Chalasani, and J. Friend. Microscale concert hall acoustics to produce uniform ultrasound stimulation for targeted sonogenetics in hstrpa1-transfected cells". *Advanced NanoBiomed Research*, **2**(2100135):1-9, 2022.
1. ​U. Magaram, C. Weiss, A. Vasan, K. C. Reddy, J. Friend, and S. H. Chalasani. Two pathways are required for ultrasound-evoked behavioral changes in caenorhabditis elegans. *PLoS One*, **17**(5):1-12, 2022.
1. ​J. Wang, F. Allein, C. Floer, N. Boechler, J. Friend, and O. V. Mena. Negative-index acoustic metamaterial operating above 100 khz in water using microstructured silicon chips as unit cells. *Advanced Materials Technologies*, (2200407):1-11, 2022.

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Controlled droplet ejection and atomization, now including acoustically-driven freezing and thawing

Ejecting droplets on demand at up to 45 degrees from an orifice via surface acoustic waves, with precise and linear control of ejection angle. In Connacher, et al., PRL 2020 and Horesh, et al., APL 2023


Making lithium ion and metal rechargeable batteries fast-chargeable for 250 to 2000 cycles

A new method to enable ten-minute 0 to 100% charging of lithium metal batteries to over 250 cycles. Also works for lithium ion batteries,making it possible to recharge 0 to 100% in 10 min for over 2000 cycles. Now featured in a new company, Sonocharge with a recent publication.

Acoustogeometric streaming

Acoustogeometric streaming is a new form of acoustic streaming that couples the deformation of the surrounding channel with the acoustic wave to produce high pressures and rapid fluid flow, especially effective at the nano scale in manipulating, splitting, merging, and mixing 200 fL droplets.

Our research group (Current & Former)

Current members

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Yau (Oscar) Yun

Oscar is currently a BS/MS student in the Department of Mechanical and Aerospace Engineering (MAE) at UC San Diego, specializing in biomedical engineering through the comprehensive exam track. He also engaged in research with Dr. James Friend in the MAE department. He explored the field of biomedical engineering and medical devices as an undergraduate and hoped to create an impact and help more people from an engineering approach. In his undergraduate research projects related to neurosurgery and interventional cardiology, he developed interest in disease pathology, surgery, and found fulfillment while volunteering and shadowing at the UC San Diego VA Hospital. He wants to study medicine after completion of his BS/MS study with the ambition to combine engineering and medicine to solve novel problems in clinical and surgical problems.

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Sujith Jayakumar

Sujith joined the MADLab in the fall of 2023 upon being admitted as a doctoral student in the UC San Diego Department of Mechanical and Aerospace Engineering. He earned his mechanical engineering bachelor's degree from IIITDM Kancheepuram. During that time, he worked on a theory on acoustic phenomena acting on inhomogeneous fluids and also published a comprehensive analysis of the acoustic relocation process, investigating the bidirectional coupling between the acoustic fields in the transient domain. His research interests include microscale flows, drug delivery techniques, lab-on-chip, and biomedical devices. Sujith's current work examines the acoustic streaming phenomena, which he is trying to elucidate through experiments and mathematical analysis. He aims to implement this theoretical knowledge in biological and medical domains. In his free time, he likes to play badminton, and cycle and is keen on building a social network.

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Kha Nguyen

Kha is a newly admitted Ph.D. student in the department of Mechanical and Aerospace Engineering at UC San Diego. She graduated from UC San Diego with a B.S. in Bioegnineering in 2021. During her undergraduate study, she did research in diverse fields, including designing, rapid prototyping, and evaluating prosthetics for quadrupeds and humans, designing and implementing 3D speckled imaging for strain measurements in torsion, analyzing retinal implants data, and creating an automatic microfluidic system for brain and retinal organoid culturing. Her research interest includes retinal implants, ocular health monitoring systems, wearable sensors, soft robotics, and surgical devices R&D. In her free time, she loves learning about skincare, hedgehogs, how to deadlift correctly, and decoding the latest memes.

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Lei Zhang

Lei is a PhD student in the Department of Mechanical and Aerospace Engineering at UC San Diego. She received her Bachelor’s degree in Biomedical Engineering from Nanjing University in 2021. During her undergraduate study, she explored the field of nanotechnology and materials for medical application, including efficient self-assembling nanocomposite platform for cancer photothermal therapy and imaging, medical device based on superparamagnetic nanoparticles for CTCs diagnosis and stretchable bioelectronics of skin sensor based on liquid metal. Her research interests include bioelectronics and disease diagnostics. She’s currently working on surface acoustic wave devices for clinical applications. Also, she loves playing badminton, board games and hiking with friends. 

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Professor James Friend

James leads the Medically Advanced Devices Laboratory in the Center for Medical Devices at the University of California-San Diego. He is a professor in the Department of Mechanical and Aerospace Engineering, and holds the Stanford S. and Beverly P. Penner Endowed Chair in Engineering.

He has over 270 peer-reviewed research publications, including 186 journal papers and nine book chapters, and 35 patents in process or granted, completed 34 postgraduate students and supervised 23 postdoctoral staff, and been awarded over $29 million in competitive grant-based research funding over his career. He is a fellow of the IEEE. More information here.

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Dr Aditya Vasan (CEO, SonoBac, San Diego)

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Dr Phuong Truong (Research Fellow, UCSD San Diego)

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Dr Shuai Zhang (Huawei, China)

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Prof Yuta Kurashina (Tokyo University of Agriculture and Technology)

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Dr Jeremy Orosco (Researcher, HRL Laboratories, Malibu, CA)

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Dr Amihai Horesh (Researcher, Volcani Institute, Israel)

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Dr Gopesh Tilvawala (Research Staff, Abbott Medical)

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Dr William Connacher (Staff, Sonocharge, San Diego)

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Dr An Huang (CEO, SonoCharge, San Diego)

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Dr Naiqing Zhang (Huawei, Shanghai, China)

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Prof Lonnie Petersen (MIT Institute for Medical Engineering and Science)

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Jackelin Amorin Cotrina (Researcher, UC San Diego)

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Prof Kenjiro Takemura (Keio University, Japan)

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Dr Morteza Miansari (San Francisco Bay)

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Dr Sean Collignon (Dallas Texas)

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Dr Jiyang Mei (Gener8, Carlsbad, CA)

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Prof Cécile Floer (Uni Lorraine, Nancy, France)

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Edward Aminov (Apple Inc)



The 100 sqm (1050 sqft) MADLab laboratory includes fabrication, prototyping, metrology, and testing facilities. We make daily use of the extraordinary NANO3Qualcomm Institute, and ACTRI core facilities.

Fabrication facilities: laser machining

We have access to a customized Optec Lightshot excimer (193nm, 25 J/cm^2) + femtosecond (1030nm, 20W) five-axis CNC, arbitrary mask laser machining station from Optec, and is capable of machining lithium niobate, glass, all polymers, and metals. It is capable of achieving feature sizes smaller than 750nm. John Roy, an experienced local representative is often on site for training and advice. cleanroom equipment for polymer microfabrication, including a large fume hood, argon-purged glove box, class 1000 laminar flow cabinet with UV shielding for photoresist work, vacuum and dessicator stations for polymer microfabrication, extrusion, plasma etching, spin coating, casting, and integration.

Fabrication facilities: microfluidics, microscale soft robotics, and integrated microelectromechanics devices

The lab has four microassembly/microscopy stations complete with pantograph micromanipulators and custom ultrasound-based pick-and-place manipulators. We also have two microsoldering stations with wave and SMD device soldering systems., and a microassembly and testing station with pantograph micromanipulators. The lab also has a DC-2.4GHz four-port network analyzer and numerous oscilloscopes, signal generators, and amplifiers.

Metrology: high-speed videography, vibration and velocity measurement, and pressure and acoustic field measurement

The lab has a unique high-speed transmission digital holographic microscope (DHM) system from Lyncée-tec. The system offers the ability to measure fluid interface and cell membrane motion to 100 kHz real-time and continuously over the entire field of view at 1MP resolution to 3 µm lateral resolution and 10 nm displacement resolution. This system was responsible for our discovery of the mechanism driving ion channel activation in sonogenetics from ultrasound. It includes a 1.2 million fps, Photron NOVA camera.

The lab also has a 9 kHz–2.4 GHz scanning laser Doppler vibrometer, Polytec UHF-120SV, able to measure 9 kHz to 2.4 GHz acoustic wave propagation upon micro to submicron devices and a laser Doppler tachometer, Canon LV-100Z, able to measure in-plane motion to 10 m/s and 2 kHz. Due to excellent support by Polytec Irvine, the laboratory has regular access to other vibrometer and surface metrology capabilities as needed.

Wel also have a Malvern Spraytec atomized mist sizer with fixturing for nebulizers and fuel injectors.

We have fluorescent and bright-field high-speed (Photron UX100+Infinity TS) video microscopes; and microfluidics control and operation equipment (ELVEFLOW); an inverted phase contrast, epifluorescence and TIRF microscope (AmScope).

Our lab also has extensive electrical test gear, from network analyzers to lock-in amplifiers, RF arbitrary signal generators, and amplifiers.


Funding Organizations
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Helping train the next generation of engineering and scientific leaders

The group serves UCSD by teaching engineering design, dynamics, structural and fluid mechanics, acoustofluidics, micro to nano-scale fabrication, and medical device engineering courses at the undergraduate and graduate level.


Principal Investigator: Professor James Friend
Phone/Zoom: +1-858-26o-95o8 •
Faculty Assistant: Estella Mercado
Center for Medical Devices
Department of Mechanical and Aerospace Engineering • Jacobs School of Engineering
Department of Surgery • School of Medicine
University of California, San Diego
9500 Gilman Drive MC0411
La Jolla, CA 92093-0411

Offices: 344K/345C&F Structural and Materials Engineering Building
Lab: 320 Structural and Materials Engineering Building
Maps to parking, laboratories and offices.

Shipping address:
University of California, San Diego
Attn: Prof James Friend, (858) 260-9508
320 SME MC0411
7835 Trade Street
San Diego CA 92121-2460

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