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"Lee, Stephen P."
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Electronic sensor and actuator webs for large-area complex geometry cardiac mapping and therapy
2012
Curved surfaces, complex geometries, and time-dynamic deformations of the heart create challenges in establishing intimate, nonconstraining interfaces between cardiac structures and medical devices or surgical tools, particularly over large areas. We constructed large area designs for diagnostic and therapeutic stretchable sensor and actuator webs that conformally wrap the epicardium, establishing robust contact without sutures, mechanical fixtures, tapes, or surgical adhesives. These multifunctional web devices exploit open, mesh layouts and mount on thin, bio-resorbable sheets of silk to facilitate handling in a way that yields, after dissolution, exceptionally low mechanical moduli and thicknesses. In vivo studies in rabbit and pig animal models demonstrate the effectiveness of these device webs for measuring and spatially mapping temperature, electrophysiological signals, strain, and physical contact in sheet and balloon-based systems that also have the potential to deliver energy to perform localized tissue ablation.
Journal Article
Highly flexible, wearable, and disposable cardiac biosensors for remote and ambulatory monitoring
by
Branche, Paul C
,
Li, Kan
,
Wright, John A
in
Digital technology
,
Feasibility studies
,
Health informatics
2018
Contemporary cardiac and heart rate monitoring devices capture physiological signals using optical and electrode-based sensors. However, these devices generally lack the form factor and mechanical flexibility necessary for use in ambulatory and home environments. Here, we report an ultrathin (~1 mm average thickness) and highly flexible wearable cardiac sensor (WiSP) designed to be minimal in cost (disposable), light weight (1.2 g), water resistant, and capable of wireless energy harvesting. Theoretical analyses of system-level bending mechanics show the advantages of WiSP’s flexible electronics, soft encapsulation layers and bioadhesives, enabling intimate skin coupling. A clinical feasibility study conducted in atrial fibrillation patients demonstrates that the WiSP device effectively measures cardiac signals matching the Holter monitor, and is more comfortable. WiSP’s physical attributes and performance results demonstrate its utility for monitoring cardiac signals during daily activity, exertion and sleep, with implications for home-based care.Wearable electronics: digital fingers on the pulseA highly flexible, low-power wearable sensor that harvests energy and monitors cardiac signals has been developed by Lee et al. The team was led by Dr. Roozbeh Ghaffari and co-workers at MC10 Inc. and Northwestern University’s Center for Bio-Integrated Electronics at the Simpson & Querrey Institute, in collaboration with the Massachusetts General Hospital and Tsinghua University. The novel wearable sensors measure cardiac signals comparable in signal fidelity to those achievable with expensive monitoring systems used in hospitals. Wearable health-care solutions are fundamentally changing the way we monitor our well-being at all times of the day, no matter whether we are asleep at home or busy at work. The sensors reported here are lightweight, inexpensive to manufacture, robust to everyday use, and capable of wireless data transmission and energy harvesting to and from a smartphone. The approach proved successful for measuring episodic electrocardiograms (ECG) and continuous heart rate signals with significantly higher patient comfort scores compared to standard Holter monitors in an initial pilot study conducted at the Massachusetts General Hospital (MGH).
Journal Article
Wearable microfluidic biosensors with haptic feedback for continuous monitoring of hydration biomarkers in workers
2025
Real-time monitoring of hydration biomarkers in tandem with biophysical markers can offer valuable physiological insights about heat stress and related thermoregulatory response. These metrics have been challenging to achieve with wearable sensors. Here we present a closed-loop electrochemical/biophysical wearable sensing device and algorithms that directly measure whole-body sweat loss, sweating rate, sodium concentration, and sodium loss with electrode arrays embedded in a microfluidic channel. The device contains two temperature sensors for skin temperature and thermal flux recordings, and an accelerometer for real-time monitoring of activity level. An onboard haptic module enables vibratory feedback cues to the wearer once critical sweat loss thresholds are reached. Data is stored onboard in memory and autonomously transmitted via Bluetooth to a smartphone and cloud portal. Field studies conducted in physically demanding activities demonstrate the key capabilities of this platform to inform hydration interventions in highly challenging real-world settings.
Journal Article
Soft, skin-interfaced microfluidic systems with integrated immunoassays, fluorometric sensors, and impedance measurement capabilities
2020
Soft microfluidic systems that capture, store, and perform biomarker analysis of microliter volumes of sweat, in situ, as it emerges from the surface of the skin, represent an emerging class of wearable technology with powerful capabilities that complement those of traditional biophysical sensing devices. Recent work establishes applications in the real-time characterization of sweat dynamics and sweat chemistry in the context of sports performance and healthcare diagnostics. This paper presents a collection of advances in biochemical sensors and microfluidic designs that support multimodal operation in the monitoring of physiological signatures directly correlated to physical and mental stresses. These wireless, battery-free, skin-interfaced devices combine lateral flow immunoassays for cortisol, fluorometric assays for glucose and ascorbic acid (vitamin C), and digital tracking of skin galvanic responses. Systematic benchtop evaluations and field studies on human subjects highlight the key features of this platform for the continuous, noninvasive monitoring of biochemical and biophysical correlates of the stress state.
Journal Article
Materials for multifunctional balloon catheters with capabilities in cardiac electrophysiological mapping and ablation therapy
by
Kim, Dae-Hyeong
,
Hwang, Sukwon
,
Won, Sang-Min
in
639/301/1005/1009
,
639/301/54/990
,
692/700/565/2773
2011
Developing advanced surgical tools for minimally invasive procedures represents an activity of central importance to improving human health. A key challenge is in establishing biocompatible interfaces between the classes of semiconductor device and sensor technologies that might be most useful in this context and the soft, curvilinear surfaces of the body. This paper describes a solution based on materials that integrate directly with the thin elastic membranes of otherwise conventional balloon catheters, to provide diverse, multimodal functionality suitable for clinical use. As examples, we present sensors for measuring temperature, flow, tactile, optical and electrophysiological data, together with radiofrequency electrodes for controlled, local ablation of tissue. Use of such ‘instrumented’ balloon catheters in live animal models illustrates their operation, as well as their specific utility in cardiac ablation therapy. The same concepts can be applied to other substrates of interest, such as surgical gloves.
Inflatable balloon catheters are widely used in many surgical and diagnostic procedures. Such catheters have now been used as a platform for a collection of components including semiconductor devices, sensors and actuators, and these multifunctional catheters probed for their use in cardiac-related applications.
Journal Article
A wireless and battery-less implant for multimodal closed-loop neuromodulation in small animals
2023
Fully implantable wireless systems for the recording and modulation of neural circuits that do not require physical tethers or batteries allow for studies that demand the use of unconstrained and freely behaving animals in isolation or in social groups. Moreover, feedback-control algorithms that can be executed within such devices without the need for remote computing eliminate virtual tethers and any associated latencies. Here we report a wireless and battery-less technology of this type, implanted subdermally along the back of freely moving small animals, for the autonomous recording of electroencephalograms, electromyograms and body temperature, and for closed-loop neuromodulation via optogenetics and pharmacology. The device incorporates a system-on-a-chip with Bluetooth Low Energy for data transmission and a compressed deep-learning module for autonomous operation, that offers neurorecording capabilities matching those of gold-standard wired systems. We also show the use of the implant in studies of sleep–wake regulation and for the programmable closed-loop pharmacological suppression of epileptic seizures via feedback from electroencephalography. The technology can support a broader range of applications in neuroscience and in biomedical research with small animals.
A tether-less and battery-less implant allows for the recording of electroencephalograms, electromyograms and body temperature in freely moving small animals, and for closed-loop neuromodulation via optogenetics and pharmacology.
Journal Article
Expression of a Bacterial Ice Nucleation Gene in Plants
by
Stephen P. Lee
,
Mindrinos, Michael N.
,
Panopoulos, Nicholas J.
in
Adaptation to environment and cultivation conditions
,
Agronomy. Soil science and plant productions
,
bacterial proteins
1992
We have introduced an ice nucleation gene (inaZ) from Pseudomonas syringae pv. syringae into Nicotiana tabacum, a freezing-sensitive species, and Solanum commersonii, a freezing-tolerant species. Transformants of both species showed increased ice nucleation activity over untransformed controls. The concentration of ice nuclei detected at -10.5°C in 15 different primary transformants of S. commersonii varied by over 1000-fold, and the most active transformant contained over 100 ice nuclei/mg of tissue. The temperature of the warmest freezing event in plant samples of small mass was increased from approximately -12°C in the untransformed controls to -4°C in inaZ-expressing transformants. The threshold nucleation temperature of samples from transformed plants did not increase appreciably with the mass of the sample. The most abundant protein detected in transgenic plants using immunological probes specific to the inaZ protein exhibited a higher mobility on sodium dodecyl sulfate polyacrylamide gels than the inaZ protein from bacterial sources. However, some protein with a similar mobility to the inaZ protein could be detected. Although the warmest ice nucleation temperature detected in transgenic plants is lower than that conferred by this gene in P. syringae (-2°C), our results demonstrate that the ice nucleation gene of P. syringae can be expressed in plant cells to produce functional ice nuclei.
Journal Article
Molecular cloning of abscisic acid-responsive mRNAs expressed during the induction of freezing tolerance in bromegrass (Bromus inermis Leyss) suspension culture
1993
Abscisic acid (ABA) increases the freezing tolerance of bromegrass (Bromus inermis Leyss) cell-suspension cultures at 23 degrees C and elicits many metabolic changes similar to those observed during cold acclimation. Induction and maintenance of freezing tolerance by ABA is accompanied by the expression of novel polypeptides and translatable RNAs. The objective of this study was to isolate and characterize ABA-responsive cDNAs associated with ABA-induced freezing tolerance in bromegrass cell cultures. Among the 16 ABA-responsive cDNA clones isolated, 9 were expressed only with ABA treatment, 7 showed increased transcript level, and 1 was transiently expressed. Cold responsiveness was determined in three clones with increased transcript levels and in the transiently expressed clone. Deacclimation of ABA-hardened cells was a relatively slow process, because all of the novel transcripts persisted for at least 7 d after cells were cultured in ABA-free medium. Preliminary sequencing of cDNAs has identified several clones that share high sequence homology with genes associated with sugar metabolism, osmotic stress, and protease activity. Clone pBGA61 was fully sequenced and tentatively identified as an NADPH-dependent aldose reductase. The predicted amino acid sequence of the coding region shared 92% similarity with that predicted for barley aldose reductase cDNA. It is proposed that expression of genes related to sugar metabolism and osmotic stress may be required for ABA-induced hardening
Journal Article
The Development of a Digital Twin Framework for an Industrial Robotic Drilling Process
by
Lee, Stephen K. H.
,
Hinchy, Eoin P.
,
Farhadi, Ahmad
in
Aerospace industry
,
Collaboration
,
digital twin
2022
A digital twin is a digital representation of a physical entity that is updated in real-time by transfer of data between physical and digital (virtual) entities. In this manuscript we aim to introduce a digital twin framework for robotic drilling. Initially, a generic reference model is proposed to highlight elements of the digital twin relevant to robotic drilling. Then, a precise reference digital twin architecture model is developed, based on available standards and technologies. Finally, real-time visualisation of drilling process parameters is demonstrated as an initial step towards implementing a digital twin of a robotic drilling process.
Journal Article
Atezolizumab with or without bevacizumab in unresectable hepatocellular carcinoma (GO30140): an open-label, multicentre, phase 1b study
2020
Dual blockade of PD-L1 and VEGF has enhanced anticancer immunity through multiple mechanisms and augmented antitumour activity in multiple malignancies. We aimed to assess the efficacy and safety of atezolizumab (anti-PD-L1) alone and combined with bevacizumab (anti-VEGF) in patients with unresectable hepatocellular carcinoma.
GO30140 is an open-label, multicentre, multiarm, phase 1b study that enrolled patients at 26 academic centres and community oncology practices in seven countries worldwide. The study included five cohorts, and the two hepatocellular carcinoma cohorts, groups A and F, are described here. Inclusion criteria for these two groups included age 18 years and older; histologically, cytologically, or clinically (per American Association for the Study of Liver Diseases criteria) confirmed unresectable hepatocellular carcinoma that was not amenable to curative treatment; no previous systemic treatment; and Eastern Cooperative Oncology Group performance status of 0 or 1. In group A, all patients received atezolizumab (1200 mg) and bevacizumab (15 mg/kg) intravenously every 3 weeks. In group F, patients were randomly assigned (1:1) to receive intravenous atezolizumab (1200 mg) plus intravenous bevacizumab (15 mg/kg) every 3 weeks or atezolizumab alone by interactive voice-web response system using permuted block randomisation (block size of two) and stratification factors of geographical region; macrovascular invasion, extrahepatic spread, or both; and baseline α-fetoprotein concentration. Primary endpoints were confirmed objective response rate in all patients who received the combination treatment for group A and progression-free survival in the intention-to-treat population in group F, both assessed by an independent review facility according to Response Evaluation Criteria in Solid Tumors version 1.1. In both groups, safety was assessed in all patients who received at least one dose of any study treatment. This study is registered with ClinicalTrials.gov, NCT02715531, and is closed to enrolment.
In group A, 104 patients were enrolled between July 20, 2016, and July 31, 2018, and received atezolizumab plus bevacizumab. With a median follow-up of 12·4 months (IQR 8·0–16·2), 37 (36%; 95% CI 26–46) of 104 patients had a confirmed objective response. The most common grade 3–4 treatment-related adverse events were hypertension (13 [13%]) and proteinuria (seven [7%]). Treatment-related serious adverse events occurred in 25 (24%) patients and treatment-related deaths in three (3%) patients (abnormal hepatic function, hepatic cirrhosis, and pneumonitis). In group F, 119 patients were enrolled and randomly assigned (60 to atezolizumab plus bevacizumab; 59 to atezolizumab monotherapy) between May 18, 2018, and March 7, 2019. With a median follow-up of 6·6 months (IQR 5·5–8·5) for the atezolizumab plus bevacizumab group and 6·7 months (4·2–8·2) for the atezolizumab monotherapy group, median progression-free survival was 5·6 months (95% CI 3·6–7·4) versus 3·4 months (1·9–5·2; hazard ratio 0·55; 80% CI 0·40–0·74; p=0·011). The most common grade 3–4 treatment-related adverse events in group F were hypertension (in three [5%] patients in the atezolizumab plus bevacizumab group; none in the atezolizumab monotherapy group) and proteinuria (in two [3%] patients in the atezolizumab plus bevacizumab group; none in the atezolizumab monotherapy group). Treatment-related serious adverse events occurred in seven (12%) patients in the atezolizumab plus bevacizumab group and two (3%) patients in the atezolizumab monotherapy group. There were no treatment-related deaths.
Our study shows longer progression-free survival with a combination of atezolizumab plus bevacizumab than with atezolizumab alone in patients with unresectable hepatocellular carcinoma not previously treated with systemic therapy. Therefore, atezolizumab plus bevacizumab might become a promising treatment option for these patients. This combination is being compared with standard-of-care sorafenib in a phase 3 trial.
F Hoffmann-La Roche/Genentech.
Journal Article