Measurement of optical reflection and temperature changes after blood occlusion using a wearable device

Mandibular reconstruction using an iliac bone flap with perforator-supported external oblique abdominal muscle island: a pilot study

The deep circumflex iliac artery (DCIA) flap is one of the bone flaps commonly used for mandibular reconstruction. Observation of the skin paddle and Doppler ultrasound are methods that are usually used to monitor DCIA flaps after mandibular reconstruction surgery. The aim of this study was to introduce a novel DCIA flap with a perforator-supported external oblique abdominal muscle (EOAM) island for postoperative flap monitoring. This study included five patients who underwent mandibular reconstruction using this modified technique. The DCIA flap and the EOAM island supplied by the ascending branch of the DCIA were harvested during the surgery. After mandibular reconstruction, the EOAM island was placed in the submandibular region to monitor the blood supply to the DCIA flap after surgery. The blood supply to the DCIA flap was monitored by observing the colour, texture, and bleeding condition of the EOAM island. After the monitoring period, the EOAM was removed and the ascending branch of the DCIA was ligated. The outcome was successful in all patients. The EOAM island supported by the ascending branch of the DCIA is reliable and safe, thus providing a robust option to monitor the blood supply to the DCIA flap.

Regulated extravascular microenvironment via reversible thermosensitive hydrogel for inhibiting calcium influx and vasospasm

Arterial vasospasm after microsurgery can cause severe obstruction of blood flow manifested as low tissue temperature, leading to tissue necrosis. The timely discovery and synchronized treatment become pivotal. In this study, a reversible, intelligent, responsive thermosensitive hydrogel system is constructed employing both the gel–sol transition and the sol–gel transition. The “reversible thermosensitive (RTS)” hydrogel loaded with verapamil hydrochloride is designed to dynamically and continuously regulate the extravascular microenvironment by inhibiting extracellular calcium influx. After accurate implantation and following in situ gelation, the RTS hydrogel reverses to the sol state causing massive drug release to inhibit vasospasm when the tissue temperature drops to the predetermined transition temperature. Subsequent restoration of the blood supply alleviates further tissue injury. Before the temperature drops, the RTS hydrogel maintains the gel state as a sustained-release reservoir to prevent vasospasm. The inhibition of calcium influx and vasospasm in vitro and in vivo is demonstrated using vascular smooth muscle cells, mice mesenteric arterial rings, and vascular ultrasonic Doppler detection. Subsequent animal experiments demonstrate that RTS hydrogel can promote tissue survival and alleviate tissue injury responding to temperature change. Therefore, this RTS hydrogel holds therapeutic potential for diseases requiring timely detection of temperature change.

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Proposing a new strategy for the discovery and treatment for diseases requiring timely detection of temperature change.

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Applying both the gel–sol transition and the sol–gel transition of PEG/PLGA triblock polymers.

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Realizing the dynamical and continuous regulation of the extravascular microenvironment.

Wearable, wireless, multi-sensor device for monitoring tissue circulation after free-tissue transplantation: a multicentre clinical trial

Wearable sensors have seen remarkable recent technological developments, and their role in healthcare is expected to expand. Specifically, monitoring tissue circulation in patients who have undergone reconstructive surgery is critical because blood flow deficiencies must be rescued within hours or the transplant will fail due to thrombosis/haematoma within the artery or vein. We design a wearable, wireless, continuous, multipoint sensor to monitor tissue circulation. The system measures pulse waves, skin colour, and tissue temperature to reproduce physician assessment. Data are analysed in real time for patient risk using an algorithm. This multicentre clinical trial involved 73 patients who underwent transplant surgery and had their tissue circulation monitored until postoperative day 7. Herein, we show that the overall agreement rate between physician and sensor findings is 99.2%. In addition, the patient questionnaire results indicate that the device is easy to wear. The sensor demonstrates non-invasive, real-time, continuous, multi-point, wireless, and reliable monitoring for postoperative care. This wearable system can improve the success rate of reconstructive surgeries.

Materials, Electrical Performance, Mechanisms, Applications, and Manufacturing Approaches for Flexible Strain Sensors

With the recent great progress made in flexible and wearable electronic materials, the upcoming next generation of skin-mountable and implantable smart devices holds extensive potential applications for the lifestyle modifying, including personalized health monitoring, human-machine interfaces, soft robots, and implantable biomedical devices. As a core member within the wearable electronics family, flexible strain sensors play an essential role in the structure design and functional optimization. To further enhance the stretchability, flexibility, sensitivity, and electricity performances of the flexible strain sensors, enormous efforts have been done covering the materials design, manufacturing approaches and various applications. Thus, this review summarizes the latest advances in flexible strain sensors over recent years from the material, application, and manufacturing strategies. Firstly, the critical parameters measuring the performances of flexible strain sensors and materials development contains different flexible substrates, new nano- and hybrid- materials are introduced. Then, the developed working mechanisms, theoretical analysis, and computational simulation are presented. Next, based on different material design, diverse applications including human motion detection and health monitoring, soft robotics and human-machine interface, implantable devices, and biomedical applications are highlighted. Finally, synthesis consideration of the massive production industry of flexible strain sensors in the future; different fabrication approaches that are fully expected are classified and discussed.