In a recent article published in the journal Device, researchers introduced an innovative soft robot called "SmartSleeve," that can directly deliver drugs to the heart's surface in response to electrical signals. This device can sense the heart's electrocardiogram (ECG) and release drugs on demand through self-sealing pores, potentially improving the treatment of cardiac diseases such as arrhythmias, myocardial infarction, and heart failure.
Study: SmartSleeve: A Soft Robotic Device for Epicardial Drug Delivery. Image Credit: YAKOBCHUK VIACHESLAV/Shutterstock.com
Background
Epicardial drug delivery is a promising strategy to enhance the therapeutic efficacy and reduce the systemic side effects of drugs targeting the heart. However, current methods lack precise control over drug dosing and timing and do not respond to local physiological cues. Additionally, existing systems require sutures or surgical implantation, which can cause tissue damage and inflammation. Therefore, there is a need for a more sophisticated and minimally invasive platform that enables controlled, localized, and sensor-enabled drug delivery to the epicardium.
About the Research
In this paper, the authors present SmartSleeve, a sutureless, sensor-enabled, soft robotic device designed for targeted epicardial drug delivery. The device can initiate or halt drug delivery based on real-time epicardial ECG sensing. SmartSleeve consists of two primary components: the SoftSwitch, a soft robotic drug delivery system, and the Bioadhesive Electronic Interface (BEI).
The SoftSwitch employs a single-reservoir system that controls drug release through a self-sealing silicone pore. This pore opens under pneumatic pressure exceeding a set threshold and closes when the pressure is released. The drug delivery rate can be adjusted by modifying several parameters, including pore size, membrane pre-stretch, actuation rate, and volume. Additionally, multiple SoftSwitch units can be linked to create a multi-reservoir system capable of delivering different drugs with precise spatial and temporal control.
The BEI, a flexible and conductive layer, adheres to the epicardial surface to detect ECG signals. It is composed of a polyurethane layer coupled with a conductive hydrogel layer, which together create strong, reversible bonds with the epicardial tissue. The BEI also transmits electrical signals to an external monitoring system via connecting wires.
SmartSleeve integrates the SoftSwitch with the BEI within a thermoplastic polyurethane (TPU) housing, which provides structural support and ensures adaptability to the epicardium's curved or uneven surface. This innovative assembly allows the SmartSleeve to attach securely to the epicardium without the need for sutures, sense the ECG signals through the BEI, and deliver drugs on-demand in response to detected ECG changes while also confirming drug delivery through changes in the ECG readings.
Research Findings
The performance and functionality of the newly proposed soft robot were tested both in vitro and in vivo using rodent (lab) and porcine (animal) models. The outcomes demonstrated that the SmartSleeve achieved on-off drug release with zero baseline release and was highly tunable by adjusting manufacturing and actuation parameters.
The device adhered to the epicardial surface without sutures and sensed the ECG signal with high fidelity and stability. It delivered drugs to the epicardium faster and more effectively than systemic delivery, modulating the physiological response by varying the drug dose and delivery location. Additionally, it released drugs in response to ECG sensing of a predetermined trigger signal and confirmed the drug delivery by detecting changes in the ECG signal.
Application
The developed device has potential implications in various clinical scenarios. For instance, it can be implanted during cardiac surgery to monitor and treat postoperative arrhythmias, such as atrial fibrillation or ventricular tachycardia, by delivering antiarrhythmic drugs on demand.
In patients with congestive heart failure, it can also be used to deliver inotropic drugs like dobutamine or milrinone to improve cardiac contractility and output, reducing systemic side effects and the need for continuous infusion.
Additionally, it can be used in patients with myocardial infarction to deliver drugs that modulate inflammation and scar formation, such as anti-inflammatory agents or growth factors, enhancing myocardial regeneration and recovery.
Conclusion
In summary, the novel SmartSleeve device proved effective for delivering drugs to the epicardial surface in response to epicardial ECG sensing. It could provide a sophisticated platform for studying epicardial drug delivery, with the potential to transform cardiac therapy in clinical applications such as postoperative arrhythmia management, myocardial healing modulation, and chronic inotropic support.
Despite its potential, the researchers did acknowledge some of the challenges and limitations associated with the device, such as power supply and wireless communication, patient selection and clinical indication, and closed-loop control of drug delivery in vivo.
To circumvent these issues, the team suggested exploring soft, implantable, fluidic-driven pumps, transcutaneous energy transfer, and wireless ECG monitoring systems to enable a fully implantable device. Additionally, they emphasized the need to define criteria for patient selection and clinical indications and to develop a closed-loop control system for drug delivery in vivo.
Journal Reference
Mendez, K, L., et, al. SmartSleeve: A sutureless, soft robotic epicardial device that enables switchable on-off drug delivery in response to epicardial ECG sensing. Device, 2024, 100419. https://doi.org/10.1016/j.device.2024.100419, https://www.sciencedirect.com/science/article/pii/S266699862400262X.
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