About

Ana Claudia Arias is a Professor in the EE Division at UC Berkeley and serves as the Chair of the department. She received her PhD in Physics from the University of Cambridge, UK, in 2001, and her master’s and bachelor’s degrees in Physics from the Federal University of Paraná in Curitiba, Brazil, in 1997 and 1995 respectively. Prior to joining UC Berkeley in January 2011, she was the Manager of the Printed Electronic Devices Area and a Member of Research Staff at PARC, a Xerox Company, and led the semiconductor group at Plastic Logic in Cambridge, UK. Her research focuses on the use of electronic materials processed from solution in flexible electronic systems, employing printing techniques to fabricate large-area electronic devices and sensors. Her work aims to advance the development of flexible and printed electronics, contributing to the fields of physical electronics and power and energy. She has been recognized as an IEEE Fellow and a Fellow of the National Academy of Inventors in 2025, among other honors.

Research topics

• Computer Science
• Materials science
• Nanotechnology
• Electrical engineering
• Embedded system
• Artificial Intelligence
• Biology
• Optoelectronics
• Chemistry
• Physics
• Mechanical engineering
• Physical medicine and rehabilitation
• Neuroscience
• Computer vision
• Speech recognition
• Human–computer interaction
• Electronic engineering
• Engineering

Selected publications

• Microwave Pilot Tone: Coil Array with Integrated RF Mixing for Efficient Motion Sensing

  Proceedings on CD-ROM - International Society for Magnetic Resonance in Medicine. Scientific Meeting and Exhibition/Proceedings of the International Society for Magnetic Resonance in Medicine, Scientific Meeting and Exhibition · 2025-09-16

  article

  Motivation: To develop a more efficient, sensitive and integrated solution to current motion sensing techniques. Goal(s): Demonstrate a mixer-on-coil approach to motion sensing that allows for freedom in choice of RF frequency without relying on the scanner's hardware. Approach: We incorporate mixers onto receivers coils to efficiently mix down motion modulated high frequency signals into a tone that lies within the receiver's bandwidth and compare its performance to Pilot Tone (PT). Results: In cardiac and respiratory motion sensing, μPT demonstrates a x3-4 increase in percent modulation when compared to PT, aligning closely with PPG and bellow recordings with minimal impact on the noise floor. Impact: μPT would enable efficient, higher sensitivity to motion at arbitrary frequencies, by leveraging on-coil mixing and minimizing cabling.

  PublisherDOI

• High-voltage water-scarce hydrogel electrolytes enable mechanically safe stretchable Li-ion batteries

  Science Advances · 2025-04-09 · 24 citations

  articleOpen access

  Soft Li-ion batteries, based on conventional organic electrolytes, face performance degradation challenges due to moisture penetration and safety concerns due to possible leakage of toxic fluorine compounds and flammable solvents under mechanical damage. We design a water-scarce hydrogel electrolyte with fluorine-free lithium salt to achieve wide electrochemical stability window (up to 3.11 volts) in ambient air without hermetic packaging while balancing high stretchability (1348%), ion conductivity (41 millisiemens per centimeter), and self-healing capabilities for mechanically and chemically safe stretchable Li-ion batteries. Molecular synergy between hydrophilicity and lithiophilicity of zwitterionic polymer backbone is revealed by molecular dynamics simulations. The battery exhibits capacity retention under harsh mechanical stresses-enduring stretching, twisting, folding, and multiple through-punctures by a needle-while self-healing from repeated through cuts by a razor blade. Stable ambient operation for 1 month over 500 charge-discharge cycles (average coulomb efficiency, 95%) is achieved. A prototype self-healing electronic system with embedded soft batteries demonstrates practical application as a durable embodied energy source.

  PublisherDOI

• The effect of soil water content and crop canopy on passive UHF-RFID wireless links

  Computers and Electronics in Agriculture · 2025-05-17 · 6 citations

  articleOpen accessSenior authorCorresponding

  The maximum wireless reading distance between and RFID tag and a reader depends on soil moisture and crop type. • Wet soil limits read range of battery-free RFID tags. • A few cm of space between tag and soil increases read range by 1 m or more. • Soil can be a more significant range limiter than scattering from crops for battery-free RFID tags. • RFID can enable above-canopy reading of battery free sensors which are in the soil. High spatial density agricultural sensors that monitor soil fertility and moisture levels are quickly developing and could revolutionize precision agriculture once they are integrated with wireless communication systems. Passive Ultra High Frequency Radio Frequency Identification (UHF-RFID) is a wireless communication protocol for battery-free sensor nodes which could enable continuous soil monitoring. Soil texture, soil water content, and crop canopy impact the vertical read range between a passive RFID tag near the soil and a reader raised above the crop. Here, we evaluated these impacts and found that increases in soil water content decreased read range by 30–40 cm compared to dry soil. Adding 3.4 cm of distance between the wet soil and the tag increased the read range by 1–1.4 m. Crop canopy did not have a significant impact on read range once the soil water content had been accounted for.

  PublisherDOI

• Antifungal Prescribing in European Pediatric Intensive Care Units: Results of a Multinational 3-Month Weekly Point-Prevalence Survey

  Journal of the Pediatric Infectious Diseases Society · 2025-09-10 · 2 citations

  article

  BACKGROUND: Critically ill pediatric patients admitted to the pediatric intensive care unit (PICU) are highly vulnerable to infections, including invasive fungal diseases and antifungal agents are frequently prescribed. Little is known about antifungal usage in PICUs across Europe. METHODS: A multinational 3-month weekly point-prevalence study for measuring antifungal drug use was organized. Eigtheen PICUs (16 hospitals) in 10 countries in the European region participated. All patients hospitalized in the participating PICUs and receiving systemic antifungals were included. Information about ward demographics was collected once; weekly ward and patient data were collected prospectively for the 12-week study period and entered in REDCap database. RESULTS: Among 18 PICUs, 8 (44%) followed prophylactic practices for targeted group of patients, 7/18 (39%) had an antifungal stewardship program and the majority (16/18, 89%) had the capacity of biomarker utilization (16/16 galactomannan, 13/16 beta-D-glucan, and 9/16 pan-fungal PCR). One hundred one courses in equal number of patients were recorded; 14 for patients aged <3 month, 87 for patients ≥3 month. Malignancy was the most common underlying condition among patients aged ≥3 month (29%) followed by surgery/trauma (25%), whereas all patients <3 month had undergone a recent surgery. Indication for antifungal prescribing was prophylaxis in 38% and treatment in 62% [empirical (57%), preemptive (13%), and targeted (30%)]. Fluconazole was the most common agent both for prophylaxis and treatment, whereas liposomal amphotericin B was the most frequent agent for targeted treatment. The majority (63%) of patients on prophylaxis were oncology or transplant patients. Common reasons for empirical and targeted treatment were persistent fever/other signs of infections in high-risk patients (61%) and Candida infections (100%), respectively. For targeted treatment, the most frequent pathogens were Candida albicans (37%) and Candida parapsilosis (32%). CONCLUSIONS: Most antifungal prescriptions across European PICUs were for treatment. Fluconazole was the most frequently prescribed antifungal. These surveillance data can guide antifungal stewardship strategies in PICUs.

  PublisherDOI

• Highly Crosslinked pAA-PEGDA Hydrogels for T1 modification in Quantitative, Anthropomorphic Phantoms

  Proceedings on CD-ROM - International Society for Magnetic Resonance in Medicine. Scientific Meeting and Exhibition/Proceedings of the International Society for Magnetic Resonance in Medicine, Scientific Meeting and Exhibition · 2025-09-16

  article

  Motivation: Phantoms are tremendously useful for advancing quantitative MRI (qMRI). But anthropomorphic phantoms that truly mimic anatomy and the heterogeneity of relaxation parameters in tissue are still out of reach. Goal(s): Our work aims to develop reproducible methods for stable control of T1 modulation in UV curable hydrogels without paramagnetic ions that often diffuse without water-tight boundaries. Approach: We modulate T1 by modifying the polymeric network of our polyacrylamide-polyethylene glycol (pAA-PEGDA) hydrogels,enabling boundaryless T1 contrast between compartments. Results: Our solution is able to bypass issues of dopant diffusion to create stable, precisely bounded regions of hydrogel with distinct T1 values. Impact: A reliable, quantitative method for T1 modification in boundaryless hydrogel systems presents a significant opportunity for development in anthropomorphic phantoms. These phantoms have the potential to accelerate the development of quantitative MRI by making research more standardized, reliable, and accessible.

  PublisherDOI

• Towards wireless flexible printed electronics

  2025-09-15

  article1st authorCorresponding

  Flexible electronics enable large area, lightweight, thin functional devices that are conformal to the human body. These electronic devices are important in Internet of Things applications as they enable interfacing electronics with complex physical objects. Flexible sensors are being developed in industries including automotive, packaging, and structural health monitoring. Wearable medical technology has seen considerable advancement in recent years in both consumer health monitoring products such as smart watches and research of clinical grade sensors. Sensors including temperature, heart rate, blood oxygenation, and various metabolites present in sweat have been demonstrated. In all cases, to be truly "wearable" a device should be comfortable: conformal, lightweight, thin, and cable-less. A functional wearable device must include not only a sensor, but also a power source and communication capability. The power and communication systems should meet the same comfort criteria as the sensors.

  PublisherDOI

• Fully‐Printed Ion Sensor Arrays for Measuring Agricultural Nitrogen and Potassium Concentrations Using Nernstian and AI Models

  Advanced Sensor Research · 2025-02-20 · 3 citations

  articleOpen accessSenior author

  Abstract The chemical composition of growing media is a key factor for plant growth, impacting agricultural yield and sustainability. However, there is a lack of affordable chemical sensors for ubiquitous nutrient ion monitoring in agricultural applications. This work investigates using fully printed ion‐sensor arrays to measure the concentrations of nitrate, ammonium, and potassium in mixed‐electrolyte media. Ion sensor arrays composed of nitrate, ammonium, and potassium ion‐selective electrodes and a printed silver‐silver chloride (Ag/AgCl) reference electrode are fabricated and characterized in aqueous solutions in a range of concentrations that encompass what is typical for agricultural growing media (0.01 m m –1 m ). The sensors are also tested in mixed‐electrolyte solutions of NaNO 3 , NH 4 Cl, and KCl of varying concentrations, and the recorded potentials are input into Nernstian and artificial neural network models to compare the prediction accuracy of the models against ground truth. The artificial neural network models demonstrated higher accuracy over the Nernstian model, and the model using only ion‐sensor inputs is 7.5% more accurate than the Nernstian model under the same conditions. By enabling more precise and efficient fertilizer application, these sensor arrays coupled to computational models can help increase crop yields, optimize resource use, and reduce environmental impact.

  PublisherOA PDFDOI

• 3D Boundaryless Slab Phantoms

  Proceedings on CD-ROM - International Society for Magnetic Resonance in Medicine. Scientific Meeting and Exhibition/Proceedings of the International Society for Magnetic Resonance in Medicine, Scientific Meeting and Exhibition · 2025-09-16

  article

  Motivation: Modern MRI phantoms rely on physical boundaries to prevent ionic diffusion of T1/T2 modifiers across compartments. Boundaryless phantoms would more accurately mimic the heterogeneity of human anatomy. Goal(s): Produce a stable, anatomically accurate, quantitative, and boundaryless brain phantom. Approach: Segment Brainweb1 data into white and gray matter tissues, 3D print positive molds, cast negative silicone molds, then fill the molds with doped UV-curable hydrogels. Results: We developed a process to create a boundaryless phantom of white and gray matter with stable T2 contrast using iron oxide nanoparticles. Impact: To address the need for quantitative phantoms with complex, anatomically accurate geometry, we developed stackable boundaryless slab phantoms by casting UV-curable hydrogels doped with a stable T2 contrast modifier. The phantoms represent roughly 40% of the top of the brain.

  PublisherDOI

• Triple-Cue-Guided Multichannel Hydrogel Conduit to Synergistically Enhance Peripheral Nerve Repair

  ACS Nano · 2025-06-13 · 13 citations

  article

  Multichannel nerve guidance conduits (NGCs) have demonstrated superior efficacy in the regeneration of large nerve defects. Here, we present the incorporation of three synergistic guiding cues into a single multichannel hydrogel conduit: topographical guidance, a conductivity gradient, and a nerve growth factor (NGF) gradient. The aligned hydrogel conduit is fabricated through directional lyophilization of a graphene oxide (GO)/poly(vinyl alcohol) (PVA) solution. The conductivity gradient is achieved via the dopamine-induced reduction of GO, during which amino groups with a concentration gradient are simultaneously generated, facilitating the eventual formation of an NGF gradient. In vitro experiments validate the excellent guidance effect and promotion of neuritogenesis by the NGF-gradient/aligned PVA/reduced graphene oxide (rGO)/polydopamine (PDA)/heparin hydrogel conduit (denoted as NGF-AGHC) on PC12 neuronal cells. Furthermore, in vivo testing reveals that NGF-AGHC exhibits a stronger longitudinal attraction to axons and promotes remyelination. Additionally, functional recovery assessments, histological analyses, and morphological evaluations all indicate that NGF-AGHC significantly enhances peripheral nerve regeneration, with performance comparable to that of the autograft group. Altogether, through a straightforward preparation method integrating topographical guidance, conductivity gradients, and NGF gradients, our NGCs offer a promising approach to peripheral nerve repair.

  PublisherDOI

• FRI-516 Impact of comorbidities on liver transplant outcomes: assessing sex-specific differences by using machine learning analysis

  Journal of Hepatology · 2025-05-01

  article
  PublisherDOI

Recent grants

• NIH Grant R21EB015628

  NIH · $419k · 2015

• Printed and flexible photovoltaics from aqueous solutions with integrated power electronics for energy harvesting

  NSF · $360k · 2016–2019

• Printed Organic Layers for Integrated Electronics: controlling processing to achieve stability and reproducibility

  NSF · $360k · 2012–2015

Frequent coauthors

• Yasser Khan

  27 shared

• C. Heske

  Karlsruhe Institute of Technology

  25 shared

• Robert F. Cook

  25 shared

• Yang Shu

  Second Hospital of Shanxi Medical University

  25 shared

• Michael Lustig

  21 shared

• Jonathan Ting

  University of California, Berkeley

  19 shared

• R. A. Street

  Palo Alto Research Center

  19 shared

• Rikky Muller

  19 shared

Education

• B.S., Electrical Engineering

  National University of Engineering (Universidad Nacional de Ingeniería)

  2003

• M.S., Electrical Engineering and Computer Sciences

  University of California, Berkeley

  2005

• Ph.D., Electrical Engineering and Computer Sciences

  University of California, Berkeley

  2010

Awards & honors

• IEEE Fellow (2025)
• National Academy of Inventors (NAI) Fellow (2025)
• Tampere University Honorary Doctorate (2022)
• NAE Gilbreth Lectureship (2017)
• FLEXI R&D Achievements Award (2017)