Sterilization is of great importance to prevent the spread and resurgence of the COVID-19, yet sterilization methods are all energy intensive in general. Steam sterilization is easily maintained and can be applied in various scenarios with less residual pollution. However, the current steam generator (so called boiler) has brought many energy and environmental concerns. With the investigation on steam sterilization\'s features, this study proposed a clean and flexible steam generation system with the air source heat pump and water vapor compressor, and the system can be further simplified through the combination with district heating pipeline. The critical design parameters and simulated performance of the system are evaluated and optimized through a MATLAB simulation, and a prototype was built with experimental performance assessing. The results show the system has an average boiler efficiency of over 170% when the ambient temperature varies from 5 °C to 35 °C and the temperature of outlet steam is above 110 °C, and has the best economic performance when the operating period is above 3 years. Furthermore, the air-source heat pump boiler system is proved to effectively respond to the surging sterilization demands during the peaks of the COVID-19 pandemic and is well consistent with the UN Sustainable Development Goals.

An optical time-temperature steam sensor is presented based on the loss of structural color in a supramolecularly cross-linked cholesteric liquid crystal photonic coating. A gradual decrease in the selective reflection band is observed upon exposure to temperatures above 105 °C related to the cholesteric to isotropic transition temperature. The linear polymers with carboxylic acid side chains provide physical cross-linking through hydrogen bonding that allows a time-temperature-dependent order loss through the dynamic equilibrium between supramolecular dimer and free monomer states. Steam is accelerating the color loss, and autoclave experiments show that the photonic supramolecular polymer is applicable as a steam sterilization sensor for medical applications.

In this study we report antibacterial modification of Kirschner wires (K-wires) with polyluteolin (PL) toward methicillin-resistant Staphylococcus aureus (MRSA). K-wires were modified by immersing them in the luteolin-containing aqueous solution for 24 h. Characterizations using scanning electron microscopy and electrochemical methods confirmed the presence of the PL coatings on the K-wires. The PL-coated K-wires were further found to show antibacterial activity toward MRSA and remained unimpaired antibacterial activity even after the steam sterilization treatment.