Article
Chemistry, Analytical
Fernando Cardes, Nikhita Baladari, Jihyun Lee, Andreas Hierlemann
Summary: This article presents a compact and low-power CMOS readout circuit for bioelectrical signals based on a second-order delta-sigma modulator, achieving high performance and small size through optimized design.
Article
Multidisciplinary Sciences
Mohammadali Sharifshazileh, Karla Burelo, Johannes Sarnthein, Giacomo Indiveri
Summary: The study introduces an embedded device that can process intracranial EEG from epilepsy patients to detect High Frequency Oscillations in real-time. By utilizing mixed-signal neuromorphic circuits, a neural network processing system achieves state-of-the-art accuracy, sensitivity, and specificity in HFO detection.
NATURE COMMUNICATIONS
(2021)
Article
Engineering, Electrical & Electronic
Victor Medina, Ruben Garvi, Eric Gutierrez, Luis Hernandez
Summary: This brief introduces a new circuit that can be used as a mixer and as a VCO-ADC simultaneously. The power supply nodes of the inverters in a ring oscillator are sorted in two sets and connected to two different input signals. The oscillator frequency of such configuration reacts to the product of the two analog inputs, making it possible to directly digitize the low pass down converted component. A system-level approach is made to minimize unwanted beat components by adjusting the number of taps in the ring oscillator. The concept and performance of the Mixer VCO-ADC are confirmed through the design and fabrication of a 55nm CMOS chip, with measurements showing a SNDR of 51.3 dB in a 100 kHz bandwidth.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Biophysics
Venkata Suresh Vajrala, Kamil Elkhoury, Sophie Pautot, Christian Bergaud, Ali Maziz
Summary: This paper reports a novel Hollow Ring-like type electrode for sensing and/or stimulating neural activity from three-dimensional neural networks. The ring electrode architecture enables easy access to three-dimensional neural networks with reduced mechanical contact on the biological tissue, and provides improved electrical interface with cells. The hollow ring design shows great potential for developing next-generation microelectrodes for applications in neural interfaces.
BIOSENSORS & BIOELECTRONICS
(2023)
Article
Multidisciplinary Sciences
Han Sae Jung, Woo-Bin Jung, Jun Wang, Jeffrey Abbott, Adrian Horgan, Maxime Fournier, Henry Hinton, Young-Ha Hwang, Xavier Godron, Robert Nicol, Hongkun Park, Donhee Ham
Summary: This article introduces a CMOS pH localizer-imager that enables arrayed localization of aqueous acids and real-time monitoring and control of pH values. The technology can be used for high-throughput research and applications.
Review
Chemistry, Analytical
Joshua O. Usoro, Brandon S. Sturgill, Kate C. Musselman, Jeffrey R. Capadona, Joseph J. Pancrazio
Summary: While MEAs hold promise for understanding neural circuitry and neuroprosthetics, designing and demonstrating chronically reliable technology remains a challenge. Variability exists in reported study durations across different MEA types and animal species, with significant differences in chronic implantation periods and linear decay in active electrode yield observed in rodent models implanted with commercially-available devices.
Article
Biophysics
Amir Niaraki, Mehran Abbasi Shirsavar, Saurabh S. Aykar, Mehrnoosh Taghavimehr, Reza Montazami, Nicole N. Hashemi
Summary: Real-time and high-throughput monitoring of neural cells exposed to injury mechanisms using microelectrode arrays and electrical impedance spectroscopy is demonstrated in this study. Aqueous graphene is used for microelectrode fabrication, and the surface morphology and electrical properties of the electrodes are characterized. The attachment and impedance changes of the neural population on the graphene microelectrodes are quantified, and the impact of UV exposure on neural detachment is monitored.
BIOSENSORS & BIOELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Abhishek Mukherjee, Miguel Gandara, Xiangxing Yang, Linxiao Shen, Xiyuan Tang, Chen-Kai Hsu, Nan Sun
Summary: This article introduces a second-order voltage-controlled oscillator (VCO)-based continuous-time delta-sigma modulator (CTDSM) that incorporates a distributed-input VCO to reduce analog and digital powers and achieve high signal-to-noise ratio and dynamic range. The prototype chip fabricated in a 40-nm CMOS process achieves a worst case spurious-free dynamic range (SFDR) of -82 dBc and a signal-to-noise-and-distortion ratio (SNDR) of 71.8 dB with impressive figures of merit based on SNDR and dynamic range.
IEEE JOURNAL OF SOLID-STATE CIRCUITS
(2021)
Article
Engineering, Electrical & Electronic
Maliang Liu, Chenxi Zhang, Shubin Liu, Dengquan Li
Summary: This paper presents a single-channel two-step voltage-time hybrid domain ADC structure, which combines voltage domain MDAC and time domain ADC to achieve high sampling rate and accuracy. The prototype ADC fabricated in CMOS process performs well in high-speed applications, achieving high SNDR and SFDR at high conversion rates.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2022)
Article
Computer Science, Information Systems
Yi Zhong, Nan Sun
Summary: This paper reviews the first-order and high-order VCO-based Delta Sigma ADCs and introduces several techniques and architectures to mitigate the nonidealities introduced by VCO, achieving outstanding power efficiency.
TSINGHUA SCIENCE AND TECHNOLOGY
(2022)
Article
Computer Science, Information Systems
Yan Yao, Zhiqun Li, Zhennan Li, Bofan Chen, Xiaowei Wang
Summary: This paper presents a four-core LC-VCO array in 55 nm CMOS technology. The tuning range is expanded based on the multi-core VCO array technology and the switched capacitor array technology, achieving phase noise optimization in a wide tuning range. The proposed VCO array has a measured oscillation frequency range of about 3.7-10 GHz and low phase noise.
Article
Chemistry, Analytical
Chenyin Feng, Christopher L. Frewin, Md Rubayat-E Tanjil, Richard Everly, Jay Bieber, Ashok Kumar, Michael Cai Wang, Stephen E. Saddow
Summary: Carbon containing materials like graphene, carbon-nanotubes, and graphene oxide are promising electrodes for implantable neural interfaces due to their excellent conductive properties. However, the complex fabrication processes and issues with repeatability can be overcome by using pyrolyzed-photoresist-film (PPF) carbon electrodes combined with amorphous silicon carbide insulation. The electrodes show excellent electrochemical performance in oxygenated phosphate buffered solution, demonstrating potential for practical applications.
Article
Engineering, Electrical & Electronic
Huaiyu Liu, Yang Lin, Liang Qi, Yongwei Lou, Guoxing Wang, Yan Liu
Summary: This paper reviews the front-end structures and stimulation artifact mitigation techniques for neural signal instrumentation, and proposes a mixed domain level-crossing scheme for fast dynamic response. By extending the detection range of the phase detectors and introducing a phase counter, the noise optimization performance of the neural front-end is improved.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS
(2023)
Article
Chemistry, Analytical
Geoffrey Mulberry, Kevin A. White, Matthew A. Crocker, Brian N. Kim
Summary: A true dual-mode CMOS device capable of simultaneously measuring neurotransmitter release and action potential has been developed, providing the potential for a comprehensive study of neurotransmission.
Article
Biophysics
Pooja P. Kanade, Nomin-Erdene Oyunbaatar, Arunkumar Shanmugasundaram, Yun-Jin Jeong, Eung-Sam Kim, Bong-Kee Lee, Dong-Weon Lee
Summary: This study introduces a drug screening platform based on a microelectrode array integrated SU-8 cantilever, which enables simultaneous measurement of electrophysiology and contractility of cardiomyocytes. The feasibility of this platform is verified through drug tests, and it is found that some drugs have greater toxicity to contractility, highlighting the need for a reliable dual measurement platform for assessing cardiotoxicity.
BIOSENSORS & BIOELECTRONICS
(2022)
Article
Nanoscience & Nanotechnology
Nassim Rousset, Ruben Lopez Sandoval, Mario Matteo Modena, Andreas Hierlemann, Patrick M. Misun
Summary: As 3D in vitro tissue models become more prevalent, analyzing the gradients and heterogeneity of nutrient and metabolite concentrations becomes more challenging. In this study, the researchers used electrochemical biosensors to measure glucose concentrations around tissue models, allowing them to study size-dependent metabolism data.
MICROSYSTEMS & NANOENGINEERING
(2022)
Article
Engineering, Biomedical
Alessio Paolo Buccino, Xinyue Yuan, Vishalini Emmenegger, Xiaohan Xue, Tobias Ganswein, Andreas Hierlemann
Summary: This article proposes a fully automated approach to reconstruct axons from extracellular electrical-potential landscapes. The method first constructs a graph based on the voltage signal amplitudes and latencies, and then interrogates the graph to extract possible axonal branches. After pruning the axonal branches, the velocities of axonal action-potential propagation are computed.
JOURNAL OF NEURAL ENGINEERING
(2022)
Article
Neurosciences
Violetta Sessi, Bergoi Ibarlucea, Florent Seichepine, Stephanie Klinghammer, Imad Ibrahim, Andre Heinzig, Nadine Szabo, Thomas Mikolajick, Andreas Hierlemann, Urs Frey, Walter M. Weber, Larysa Baraban, Gianaurelio Cuniberti
Summary: This study introduces a hybrid integration technique that combines bottom-up silicon-nanowire Schottky-junction FETs with complementary-metal-oxide-semiconductor (CMOS) readout and amplification electronics to establish a stable biosensing platform. It enables selective detection of biomarkers at high dilution levels and shows great potential for various applications.
FRONTIERS IN NEUROSCIENCE
(2022)
Article
Multidisciplinary Sciences
Paolo S. Ravaynia, Stefan Biendl, Francesco Grassi, Jennifer Keiser, Andreas Hierlemann, Mario M. Modena
Summary: Schistosomiasis is a neglected tropical disease that affects a significant number of people annually. Due to the lack of effective drugs, repurposing compound libraries has become a viable option for accelerating drug development. A study using a high-throughput screening platform identified several potential drug candidates for the treatment of schistosomiasis.
Article
Engineering, Biomedical
Xiaohan Xue, Alessio Paolo Buccino, Sreedhar Saseendran Kumar, Andreas Hierlemann, Julian Bartram
Summary: This article introduces a novel approach to identify and monitor monosynaptic connections between neurons. The method combines high-resolution imaging and large-scale recording of electrical activity. The proposed approach offers unique advantages in accurately localizing synapses, providing precise information of presynaptic spiking, measuring postsynaptic spine Ca2+ signals, and allowing for long-term measurements.
JOURNAL OF NEURAL ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Manuel Schroter, Congwei Wang, Marco Terrigno, Philipp Hornauer, Ziqiang Huang, Ravi Jagasia, Andreas Hierlemann
Summary: This study utilizes high-density microelectrode arrays to perform large-scale electrophysiological recordings on human cerebral organoids, providing insights into their functionality and potential functional connectivity, leading to a better understanding of developing neuronal networks in brain organoids.
Review
Chemistry, Analytical
Nassim Rousset, Christian Lohasz, Julia Alicia Boos, Patrick M. Misun, Fernando Cardes, Andreas Hierlemann
Summary: Microfluidic-drop networks, consisting of stable drops connected through microfluidic channels, provide a versatile configuration for long-term organ model culturing. Mathematical modeling, such as computational fluid dynamics (CFD), is useful for designing and optimizing drop-based microfluidic devices, but lacks computational efficiency. Alternatively, the hydraulic-electric analogy is an efficient method to explore design and operation parameters of microfluidic-drop networks. A circuit-based model of hanging- and standing-drop compartments is presented, along with a phase diagram describing the nonlinearity of the capillary pressure of a hanging drop. The methodology for finding flow rates and pressures within drop networks is also discussed. This paper reviews several applications where the method outlined has been instrumental in optimizing design and operation.
Article
Engineering, Biomedical
Furkan Gokce, Alicia Kaestli, Christian Lohasz, Martina de Geus, Hans-Michael Kaltenbach, Kasper Renggli, Beat Bornhauser, Andreas Hierlemann, Mario Modena
Summary: Despite improving survival rates in pediatric leukemia patients, the outcome for certain subtypes remains poor. A microphysiological drug-testing platform has been developed to address the limitations of current screening methods, allowing for the co-culture of patient-derived leukemia cells, bone marrow cells, and liver tissues. By testing the activation of the prodrug ifosfamide in this platform, sample-specific sensitivities to ifosfamide in primary leukemia samples can be identified, providing potential for precision chemotherapy selection.
ADVANCED HEALTHCARE MATERIALS
(2023)
Article
Mathematical & Computational Biology
Taehoon Kim, Dexiong Chen, Philipp Hornauer, Vishalini Emmenegger, Julian Bartram, Silvia Ronchi, Andreas Hierlemann, Manuel Schroter, Damian Roqueiro
Summary: In this study, modern Graph Neural Networks (GNNs) were applied to analyze a large-scale electrophysiological dataset of rodent neuronal networks. The results demonstrate that the joint representation of node features and functional connectivity, extracted from baseline recordings, is informative for predicting changes in firing rate of individual neurons after a pharmacological perturbation.
FRONTIERS IN NEUROINFORMATICS
(2023)
Article
Chemistry, Multidisciplinary
Wei Wei, Fernando Cardes, Andreas Hierlemann, Mario M. M. Modena
Summary: This study presents a human-cell-based platform for monitoring the tightness of the blood-brain barrier in real time. The results demonstrate that oxygen-glucose deprivation induces cellular actin remodeling and morphological changes in endothelial cells, leading to barrier breakage. The platform recapitulates the main barrier functions and can be used to investigate the reorganization of the blood-brain barrier.
Article
Biochemical Research Methods
Nassim Rousset, Martina de Geus, Vittoria Chimisso, Alicia J. Kaestli, Andreas Hierlemann, Christian Lohasz
Summary: This paper presents an optimized pneumatic-pump system integrated with hanging-drop networks for closed-loop recirculation of particles. Experimental results suggest that the aggregation of submicron-scale cell-culture-medium components is the cause of the pseudo-no-slip boundary condition. By adjusting the height of hanging drops, the flow or stagnation of particles can be controlled, providing a foundation for controlling the residence time of single cells around 3D organ models.
Meeting Abstract
Developmental Biology
Manon Murdeu, Andreas Hierlemann, Julia Boos, Tina Buerki-Thurnherr