Biology subjects

Murmann, B.

Publications and source records attributed to Murmann, B..

3 recordsLinked to original sources

bioRxiv2025

A Framework for Compressive On-chip Action Potential Recording

Scaling neural recording systems to thousands of channels creates extreme bandwidth demands, posing a challenge for resource-constrained, implantable devices. This work introduces an adaptive, multi-stage compression framework for high-bandwidth neural interfaces. The system combines a Wired-OR analog-to-digital compressive readout with a digital core that adaptively requantizes, selectively samples, and encodes the neural signals. Although prior work suggests that action potential recordings can be re-quantized to approximately the signal-to-noise (SNR) number of bits without significantly degrading decoding performance, our results show that the required resolution can often be reduced even further. By matching the number of quantization levels to the electrodes maximum SNR ({lceil}log2 SNR{rciel} number of bits), we retain waveform fidelity while eliminating unnecessary precision that primarily captures noise. Recorded spike samples are selected using a mutual information-based criterion to preserve both spatial and temporal discriminative waveform features. A static entropy coder completes the pipeline with low computation overhead compression optimized for neural signal statistics. Evaluated on 512-channel macaque retina ex vivo data, the system preserves 90% of spikes while achieving a 1098x total compression over baseline.

bioengineering↗

bioRxiv2022

Tailoring electrode surface charge to achieve discrimination and quantification of chemically similar small molecules with electrochemical aptamers

Electrochemical biosensors based on structure-switching aptamers offer many advantages because they can operate directly in complex samples and offer the potential to integrate with miniaturized electronics. Unfortunately, these biosensors often suffer from cross-reactivity problems when measuring a target in samples containing other chemically similar molecules, such as precursors or metabolites. While some progress has been made in selecting highly specific aptamers, the discovery of these reagents remains slow and costly. In this work, we demonstrate a novel strategy to distinguish molecules with miniscule difference in chemical composition (such as a single hydroxyl group) - with cross reactive aptamer probes - by tuning the charge state of the surface on which the aptamer probes are immobilized. As an exemplar, we show that our strategy can distinguish between DOX and many structurally similar analytes, including its primary metabolite doxorubicinol (DOXol). We then demonstrate the ability to accurately quantify mixtures of these two molecules based on their differential response to sensors with different surface-charge properties. We believe this methodology is general and can be extended to a broad range of applications.

bioengineering↗

bioRxiv2021

Design considerations of a wearable electronic-skin for mental health and wellness: balancing biosignals and human factors

Chronic stress has been associated with a variety of pathophysiological risks including developing mental illness. Conversely, appropriate stress management, can be used to foster mental wellness proactively. Yet, there is no existing method that accurately and objectively monitors stress. With recent advances in electronic-skin (e-skin) and wearable technologies, it is possible to design devices that continuously measure physiological parameters linked to chronic stress and other mental health and wellness conditions. However, the design approach should be different from conventional wearables due to considerations like signal-to-noise ratio and the risk of stigmatization. Here, we present a multi-part study that combines user-centered design with engineering-centered data collection to inform future design efforts. To assess human factors, we conducted an n=24 participant design probe study that examined perceptions of an e-skin for mental health and wellness as well as preferred wear locations. We complement this with an n=10 and n=16 participant data collection study to measure physiological signals at several potential wear locations. By balancing human factors and biosignals, we conclude that the upper arm and forearm are optimal wear locations.

bioengineering↗