About

Professor Mark G. Allen is the Director of the MicroSensors and MicroActuators (MSMA) Group at the University of Pennsylvania. He holds the Alfred Fitler Moore Professorship and is a faculty member in the Electrical and Systems Engineering department, which is his primary appointment. Additionally, he is affiliated with the Mechanical Engineering and Applied Mechanics department. Professor Allen also serves as the Chair of the Electrical and Systems Engineering department. The MSMA Group under his leadership focuses on research in microsensors and microactuators, with ongoing projects involving postdoctoral fellows and graduate students working on topics such as magnetics, microfabrication, in-soil nutrient sensing, biodegradable batteries, magnetic energy harvesting, and biosensors.

Research topics

• Political Science
• Electrical engineering
• Materials science
• Engineering
• Nanotechnology
• Biology
• Immunology
• Organic chemistry
• Endocrinology
• Composite material
• Optoelectronics
• Psychology
• Chemical engineering
• Law
• Telecommunications

Selected publications

• An Integrated Photonic Magneto-Optomechanical Modulator for Protection of Switching Power Converters

  2026-01-25

  articleSenior author

  We demonstrate a fully integrated magnetooptomechanical MEMS modulator for current-induced optical switching in high-EMI environments, with application as an overcurrent protection ‘circuit breaker’ in switching power converters. The device is realized by postprocess micromachining of magnetically soft suspensions over waveguides on a foundry-fabricated silicon photonic chip. Overcurrent in a switching converter line causes magnetic actuation of the suspensions, bringing the magnetic material in proximity to the waveguide and attenuating the guided light through evanescent-field absorption. This modulated light signal can then be used to control the converter; since the control signal is optical, it has reduced susceptibility to the high-EMI environment. Two magnetic architectures - a cantilever with a magnetic flux concentrator and a folded-beam suspension - are presented. The modulator achieves 6 dB of attenuation within <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3 \mu \mathrm{s}$</tex> under overcurrent pulse excitation, validating its potential as a photonic circuit breaker for optically driven, EMI-immune power systems.

  PublisherDOI

• A Miniaturized Enzymatic Lactate Sensor for Continuous Monitoring in Oxygen-Depleted Tissue Microenvironments

  IEEE Transactions on Biomedical Engineering · 2026-01-01

  articleSenior author

  OBJECTIVE: Real-time measurement of tissue lactate levels is critical for diagnosing and monitoring metabolic disorders yet remains a challenge in dynamic physiological environments. Traditional wearable lactate sensors can provide non-invasive monitoring but are limited in their ability to capture tissue-specific information and thus diagnostic accuracy in systemic metabolic assessments. This study aims to develop an implantable microsensor for direct measurement of lactate within target tissues for continuous, real-time tracking. Recognizing that the ambient oxygen concentration in these environments may be depleted relative to oxygen concentration in, e.g., wearables, the limits of oxygen dependence of sensor operation are probed. METHODS: A miniaturized enzymatic lactate sensor (0.7×1.0×0.12 mm) was fabricated on gold electrodes with immobilized lactate oxidase, leveraging biochemical surface modifications for enhanced enzyme stability and a permselective membrane for regulation of analyte diffusion and prolonged operational lifetime in simulated biological environments. Sensor performance was evaluated electrochemically across a range of lactate concentrations. RESULTS: This sensor, tested across pathophysiological conditions, provides an expanded linear range of response (LRR) from 0.2 to 50 mM, enabling precise tracking of metabolic fluctuations with a response time of 8 s in oxygen-deficient disease microenvironments, validated by computational modelling. CONCLUSION: The sensor enables continuous monitoring of lactate levels for implantable deployment, overcoming key limitations of traditional systems in capturing local metabolic activity when tissue oxygen availability is reduced. SIGNIFICANCE: The sensor provides a platform for real-time metabolic assessment to support diagnostics, longitudinal health monitoring, and evaluation of therapeutic response in conditions such as ischemia and cancer.

  PublisherDOI

• Through-Silicon Via Coupled Inductors for Vertical Power Delivery

  IEEE Transactions on Power Electronics · 2026-01-01

  articleSenior author

  This paper presents the design, fabrication, and characterization of through-silicon via (TSV) coupled inductors for vertical power delivery. The inductors are implemented by electrodepositing thin-film magnetic material onto via sidewalls and forming two coaxial Cu layers inside vias as coupled windings. The unique coaxial winding arrangement eases fabrication constraints. Many coupled inductors can be interconnected in a fabric-like fashion and scaled to larger inductance values and current ratings. As a proof of concept, TSV coupled inductors are fabricated, achieving an inductance density of 162 nH/mm2, an L/RDC ratio of 597 nH/Ω, a coupling factor of 0.97, and a peak Q of 9 at 5.5 MHz. Inductor performance with different core thicknesses and via diameters is evaluated, showing the potential to exceed 1000 nH/mm2 in inductance density and 2500 nH/Ω in L/RDC ratio.

  PublisherDOI

• A wideband tunable, nonreciprocal bandpass filter using magnetostatic surface waves with zero static power consumption

  Nature Communications · 2026-01-14 · 1 citations

  articleOpen access

  Modern wireless systems demand compact, power-efficient radio frequency (RF) front-end components that support wideband tunability and nonreciprocity. We present a class of miniature bandpass filter that achieves both continuously tunable frequency operation (4.0-17.7 GHz) and high nonreciprocity ( > 25 dB), all within a compact size of 1.07 cm³. The filter employs a microfabricated 18 µm thick Yttrium Iron Garnet (YIG) waveguide with meander-line aluminum transducers, enabling low-loss unidirectional propagation via magnetostatic surface waves. Leveraging a benzocyclobutene planarization fabrication process, this study enables a dispersion profile unique to thick YIG films, resulting in enhanced filter skirt performance with minimal spurious modes. Frequency tuning is enabled by a zero-static-power magnetic bias circuit using transient current pulses, eliminating continuous power consumption. The filter demonstrates low insertion loss (3-5 dB), high out-of-band rejection ( > 30 dB), narrow bandwidth (100-200 MHz), robust power handling ( > 10.4 dBm), and high linearity (IIP3 > 26 dBm).

  PublisherOA PDFDOI

• Lessons Learned from a Slow Breaker Failure Operation in a POTT Scheme

  2025-03-31

  article

  Communication-assisted line protection schemes can face unexpected breaker failure (BF) trip time delays. This paper examines an actual event where a Permissive Overreach Transfer Trip (POTT) line protection scheme operated for a close-in fault as expected with the local relay issuing a permit to the remote relay. This resulted in a remote end BF initiation and subsequent longer than expected BF trip operation for a failed remote end breaker. In this event, the local breaker opened successfully causing the local relay to stop sending a permit to assert the remote end breaker failure initiate input. After a time delay, the remote end relay Zone 2 reach operated and its BF input re-asserted due to the echo key logic from the local relay. This resulted in an overall delayed response of the BF scheme to operate for the remote end failed breaker. The investigation of this event concluded that this was a slow breaker failure operation in a POTT scheme. Through detailed analysis of relay events, oscillography data, and post-event simulations, the root cause of this rare occurrence was uncovered. Three solutions were proposed to improve the BF scheme response time. This paper presents simulated solutions of the event and provides the preferred solution based on ease of implementation with improved security. In conclusion, this case study serves as a reminder that even well-designed systems can face unexpected challenges with field application. By sharing these insights, this paper aims to contribute to the ongoing improvement of power system reliability and the education of protection engineers.

  PublisherDOI

• Efficient Space Utilization of Magnetics for Wireless Energy Harvesting in Volume-Constrained Applications

  2025-06-29

  articleSenior author

  Magnetic materials are widely utilized in induction-based wireless energy harvesting for MEMS. However, the volume of these magnetic materials often comprises a large fraction of the total volume of the MEMS device; this can be challenging in many applications where the overall volume of the device is constrained by application. We present a new geometry of a wireless energy harvester (WEH) magnetic core that achieves a 43% volume reduction compared with a single solid core, while largely maintaining total harvested energy, thus improving output power density per unit volume of magnetic material by approximately 80%. The WEH design features a centrally vacant hollow magnetic core with the core sidewalls wound by two series-connected solenoids. The central hollow region is thus available for integration of other components, providing an efficient solution for volume-constrained applications.

  PublisherDOI

• Recombinant GDF11 Promotes Recovery in a Rat Permanent Ischemia Model of Subacute Stroke

  Stroke · 2025-02-06 · 2 citations

  articleOpen access

  BACKGROUND: Stroke remains a leading cause of death and disability, underscoring the urgent need for treatments that enhance recovery. GDF11 (growth differentiation factor 11), a member of the TGF-β (transforming growth factor-β) superfamily, is a circulating protein involved in cellular development and tissue repair. GDF11 has gained attention for its potential regenerative properties in aging and disease contexts, making it a candidate for stroke recovery therapies. METHODS: The therapeutic benefits of rGDF11 (recombinant GDF11) were evaluated using a rat ischemic stroke model, in which focal cerebral infarcts were induced in 8- to 10-week-old young adult male Sprague-Dawley rats by permanently occluding the proximal right middle cerebral artery. Rats received single or multiple doses of rGDF11 (0.1-4 mg/kg) or vehicle from 24 to 72 hours post-injury. Sensorimotor functions were evaluated, and brain and serum samples were examined to determine the mechanisms of action and identify biomarkers, using immunofluorescence, target-specific ELISAs, and an aptamer-based proteomics platform. RESULTS: We confirmed rGDF11 activity in vitro and in established in vivo mouse models of cardiac hypertrophy and glucose metabolism and assessed the efficacy of rGDF11 treatment in 6 preclinical stroke studies using independent Contract Research Organizations, with all study animals and treatment groups blinded. All 6 studies revealed consistent improvement in sensorimotor outcomes with rGDF11. rGDF11-treated rats showed increased cortical vascularization and radial glia in the ventricular zone. Serum analysis revealed that rGDF11 caused dose-dependent decreases in CRP (C-reactive protein) and identified novel pharmacodynamic biomarkers and pathways associated with potential mechanisms of action of rGDF11. CONCLUSIONS: These results demonstrate that systemically delivered rGDF11 enhances neovascularization, reduces inflammation, promotes neurogenesis, and improves sensorimotor function post-injury in a rat model of ischemic stroke. More importantly, these data define an optimized and clinically feasible rGDF11 dosing regimen for therapeutic development in ischemic stroke and identify a panel of candidate pharmacodynamic and mechanistic biomarkers to support clinical translation.

  PublisherOA PDFDOI

• High-speed imaging at extended SWIR wavelengths using CQDs

  2025-05-29

  articleSenior author

  Colloidal quantum dot (CQD) image sensors are an attractive technology, which offers cost-effective processing, tailorable spectral response and scalable pixel size. The first commercial infrared cameras based on CQDs have entered the market and are being deployed in machine vision and surveillance applications by early adopters. Emberion, a pioneer of this technology with an entirely in-house designed and produced CQD camera, recently published a detailed introduction to their custom-designed image sensor platform and CQD manufacturing process. Here, we extend the aforementioned report with further experimental results of high-speed SWIR imaging and introduce Emberion’s latest image sensor ROIC platform comprising two variants: (i) a MegaPixel resolution imager with 10 &mu;m pixel size and (ii) a push-broom sensor optimized for hyperspectral imaging at above 1000 fps. We report on the dynamic response of the CQD stack as a function of operating temperature and discuss the performance of CQD-based image sensors for high-speed imaging. We conclude by presenting selected application cases showcasing the high-speed performance of the Emberion VS20 camera at extended SWIR wavelengths.

  PublisherDOI

• Optical transparent packages for implantable devices

  2025-03-19

  articleSenior author

  We present a carbon dioxide (CO2) laser-assisted simultaneous localized fusion bonding and dicing technology on fused silica wafer. Direct bonding of fused silica wafer stacks results in an optically transparent package without introducing intermediate bonding layers. The temperature inside the package is maintained below 400 °C during the fabrication process to preserve complementary metal-oxide-semiconductor (CMOS)- compatibility. Such fused silica packages have many favorable features such as optical transparency for packaging micro-opto-electro-mechanical systems (MOEMS), biocompatibility and hermeticity for implantation applications, and transparency at radio frequencies for encapsulating electronics for wireless power and signal transmission. We applied this localized fusion bonding technology to encapsulate humidity sensors, evaluating the hermeticity and suggesting an implantation lifespan of over 70 years in the human body. Furthermore, we extended its application to vacuum packages and implantable tactile sensing systems to restore hand function for individuals with paralysis.

  PublisherDOI

• Small-scale, long-duration, and biodegradable zinc–air batteries

  EES batteries. · 2025-01-01 · 1 citations

  articleOpen accessSenior author

  This work presents biodegradable, wax-encapsulated zinc–air batteries for sustainable, long-term IoT applications like precision agriculture and environmental science.

  PublisherOA PDFDOI

Recent grants

• NNCI: Mid-Atlantic Nanotechnology Hub (MANTH)

  NSF · $5.3M · 2020–2026

• NIH Grant R43HL064452

  NIH · $100k · 2001

• NNCI: Mid-Atlantic Nanotechnology Hub (MANTH) for Research, Education, & Innovation

  NSF · $5.0M · 2015–2021

• In-vivo Assessment of Extracellular-Matrix-Based Micromachined Neuroelectrodes

  NIH · $443k · 2016–2018

• Collaborative Research: Integration of Implantable MEMS Sensors and Computational Modeling to Assess Mechanical Regulation of Bone Regeneration

  NSF · $135k · 2014–2017

Frequent coauthors

• David M. Sonnenfroh

  64 shared

• Sophia Muirhead

  Institute of Electrical and Electronics Engineers

  59 shared

• Juan Hernández-Cordero

  Institute of Electrical and Electronics Engineers

  59 shared

• Thomas Siegert

  University of West Florida

  59 shared

• Thomas Coughlin

  Xi'an Jiaotong University

  59 shared

• Jamie Moesch

  Arizona State University

  59 shared

• John C. Cartledge

  Human Resources Research Organization

  59 shared

• Steven Heffner

  Spectrum Research (United States)

  59 shared

Labs

• MicroSensors and MicroActuators GroupPI

Education

• Ph.D., Electrical Engineering

  University of Pennsylvania

  1988

• M.S., Electrical Engineering

  University of Pennsylvania

  1983

• B.S., Electrical Engineering

  University of Pennsylvania

  1981