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Introduction T-PLS (Twin-Pulse Life Support) is the first commercial pulsatile ECLS (Extra Corporeal Life Support) device (1). The dual sac structure of T-PLS can effectively reduce high membrane oxygenator inlet pressure and hemolysis. To verify both the use of T-PLS for ECLS and the advantages of T-PLS, we tested various models. Method and Results In the partial CPB (cardio pulmonary bypass) model (swine), T-PLS (N=6), and Biopump (N=2), a single pulsatile pump (N=2), were compared. In the case of single pulsatile flow, during pump systole, pressure increased to 700 - 800 mmHg at the inlet port of the membrane oxygenator. fHb, a hemolysis measurement value, was about 80 mg / dL at 3 hours. On the contrary, because of T-PLS's dual sac system, the pressure of T-PLS had a maximum value of about 250 mmHg and fHb was similar to that of the commercial centrifugal pumps. In the total CPB model (bovine, N=6), the heart was stopped via cardioplegia (Kcl). T-PLS flow was maintained at 3.0 - 4.5 L/min. T-PLS functioned like a natural heart, having a pulse pressure of 26 - 43 mmHg and a pulse rate of 40 - 60 bpm (beats per minute). In the emergency case model (canine, N=6), T-PLS was started 10 minutes after cardiac arrest from electronic shock. In spite of cardiac arrest for a period of 40 minutes, the heart was recovered after defibrillation. In the ARDS (Acute Respiratory Distress Syndrome) model (canine, N=6), minimal ventilator parameters were set: tidal volume 130 ml, respiration rate = bpm, FiO2 = 10%. Three hours after starting T-PLS, PO2 of the carotid artery blood (after 2 hours: 195 ±89.4; after 3 hours: 258 ±99.3 mmHg) was above half the value of the femoral artery but was within normal range. Conclusion It is suggested that a portable pulsatile ECLS like T-PLS may be used as a CPB device and as an alternative CPR (cardiopulmonary resuscitation) device in the case of cardiac arrest. Due to the pulsatile flow, oxygenated blood is delivered to the patient without overloading the ARDS patient's heart.

Zinc oxide nanoparticles (ZnO) have attracted much attention as promising antibacterial agents due to their ability to generate reactive oxygen species (ROS) that effectively eliminate bacteria. However, when they are delivered inside the body, this distinct characteristic of ROS is restricted due to the limited penetration depth of external light, which is required for the photocatalysis of particles. To produce ROS without any light source when the particles are implanted, we introduced catechol-ZnO complexes to a hyaluronic acid (HA) hydrogel platform, which can self-generate sufficient ROS in the bacteria-infected tissue. Catechol-ZnO complexes enhanced ROS generation via electron transfer from the formation of complexes and o-semiquinone, and a hydrogel structure was created by coordinate bonds between functionalized catechol groups in HA and ZnO simultaneously. This hydrogel demonstrated different behaviors in terms of physical properties compared to chemically cross-linked HA hydrogels containing ZnO. This hydrogel showed a higher swelling ratio, enzymatic degradation resistance, and tissue adhesive strength. Enhanced ROS generation was confirmed using electron paramagnetic resonance (EPR), H2O2 concentration, glutathione depletion, and intracellular ROS detection. The improved antibacterial performance of hydrogels from ROS production was also confirmed through in vitro bacterial testing against two bacterial strains, E. coli and S. aureus. Furthermore, an in vivo experiment using an infected mouse model to analyze colony formation, histologic analysis, and hematological inflammatory markers revealed the effective antibacterial effects of catechol-ZnO complexes. Overall, the potential of the hydrogel created via catechol-ZnO complexes for antibacterial therapy was demonstrated through the capability to enhance ROS generation and eradicate bacteria.

A hybridization method to prepare a hyaluronic acid (HA)‐based nanohybrid hydrogel is proposed that introduces an additional inorganic silica network via an in situ sol–gel process. HA hydrogels have been extensively studied because of their excellent biocompatibility and biological functions; however, their poor mechanical strength hinders their use in tissue engineering applications. In the present work, the sol–gel technique is employed to achieve the formation of a structurally organized silica network in the HA hydrogel matrix rather than mixing of discrete particles with the HA polymer matrix. Importantly, the silica densification process results in significant enhancement of the mechanical properties. In addition, the nanohybrid hydrogels exhibit great degradation resistance and bioactivity on both fibroblast and pre‐osteoblast cells. Moreover, the physical characteristics and biological properties can be modulated by varying the silica content; these materials thus show great potential for a wide range of applications for soft and hard tissues.

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