Inspired by the rolling mechanism of the proboscis of a butterfly, rollable electronics that can be rolled and unrolled to a great extent on demand are developed. Generally, electronic devices that are attached to various surfaces to acquire biosignals require mechanical flexibility and sufficient adhesive force. The rollable platform provides sufficient force that grips onto the entire target surface without destroying the target organ. To prove the versatility of our device not only in gripping and detecting biosignals from micro objects but also in performing a variety of functions, thin-film electronics including a heater, strain sensor and temperature sensor are constructed on the rollable platform, and it is confirmed that all the electronics operate normally in the rolled and unrolled states without breakdown. Then, micro bio-objects are gripped by using the rollable platform, and their tiny motions are successfully detected with the sensor on the platform. Furthermore, the detection of the pulse wave signals of swine under diverse experimental conditions is successfully conducted by rolling up the rollable system around the blood vessel of the swine, the result of which proves the feasibility of a rollable platform as a biomedical device.

Atherosclerotic plaques within the vasculature may eventually lead to heart failure. Currently, cardiac stenting is the most effective and least invasive approach to treat this disease. However, in-stent restenosis is a complex chronic side effect of stenting treatment. This study used coronary stents coated with stem cells secreting angiogenic growth factors via an inducible genome-editing system to reduce stent restenosis and induce re-endothelialization within the artery. The characteristics of the cells and their adhesion properties on the stents were confirmed, and the stents were transplanted into a swine model to evaluate restenosis and the potential therapeutic use of stents with stem cells. Restenosis was evaluated using optical coherence tomography (OCT), microcomputed tomography (mCT) and angiography, and re-endothelialization was evaluated by immunostaining after cardiac stent treatment. Compared to a bare metal stent (BMS) or a parental umbilical cord blood-derived mesenchymal stem cell (UCB-MSC)-coated stent, the stents with stem cells capable of the controlled release of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) successfully reduced restenosis within the stent and induced natural re-endothelialization. Furthermore, UCB-MSCs exhibited the ability to differentiate into endothelial cells in Matrigel, and HGF and VEGF improved this differentiation. Our study indicates that stents coated with UCB-MSCs secreting VEGF/HGF reduce the restenosis side effects of cardiac stenting with improved re-endothelialization.

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We evaluated the effects of Ivabradine on left ventricle (LV) ejection fraction (EF) and LV infarcted tissue in the rat myocardial ischemia-reperfusion model. Twenty rats were randomly assigned to group 1 (ischemia-reperfusion, no treatment, n=10) and group 2 (ischemia-reperfusion + Ivabradine 10 mg/kg, n=10). Ivabradine was administered for 28 days. Echocardiography was performed at 7 days and at 28 days after the induction of ischemia-reperfusion injury. Cardiac fibrosis induced by ischemia-reperfusion injury was evaluated by Masson's trichrome staining. The infarct size was quantified using the Image J program. At the 28-day follow-up, LVEF was significantly higher (36.02±6.16% vs. 45.72±2.62%, p<0.001) and fractional shortening was significantly higher (15.23±2.84% vs. 20.13±1.38%, p<0.001) in group 2 than group 1. Delta (28 day minus 7 day) EF was significantly higher in group 2 than group 1 (−4.36±3.49% vs. 4.31±5.63%, p<0.001). Also, heart rate (beats/min) was significantly lower in group 2 than group 1 (251.67±25.19 vs. 199.29±31.33, p=0.025). Group 2 had a smaller infarct size (40.70±8.94% vs. 30.19±5.89%, p<0.01) than group 1 at 28-day follow-up. Oral administration of Ivabradine could improve LV systolic function and reduce infarcted tissue area in rat myocardial ischemia-reperfusion model.

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