Visible-UVC upconversion polymer films for prevention of microbial infection.

Bacterial infections caused by the growth and reproduction of pathogenic bacteria on wounds are one of the main reasons that hinder wound healing. Antibacterial wound dressings protect wounds from bacterial infections. Herein, we developed a polymeric antibacterial composite film using polyvinyl alcohol (PVA) and sodium alginate (SA) as the substrate. The film used praseodymium-doped yttrium orthosilicate (Y2SiO5: Pr3+, YSO-Pr) to convert visible light into short-wavelength ultraviolet light (UVC) to kill bacteria. The YSO-Pr/PVA/SA showed upconversion luminescence in photoluminescence spectrometry tests, and the emitted UVC inhibited Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria in antibacterial tests. In vivo animal tests showed that YSO-Pr/PVA/SA is effective and safe for inhibiting bacteria in real wounds. The in vitro cytotoxicity test further confirmed the good biocompatibility of the antibacterial film. In addition, YSO-Pr/PVA/SA exhibited sufficient tensile strength. Overall, this study demonstrates the potential of upconversion materials for use in medical dressings.

Preparation and properties of conductive bacterial cellulose-based graphene oxide-silver nanoparticles antibacterial dressing.

It is difficult to obtain stable multifunctional silver-containing materials that are suitable for use as wound dressings. To solve this problem, we added graphene oxide (GO) to an acetobacter culture medium and used a biological blending self-growth method to fix GO onto the bacterial cellulose to form a mixed-growth film. We then used polydopamine to fix AgNPs to obtain a novel silver-based cellulose wound dressing. This composite material was characterized by infrared spectroscopy, electron microscopy, and X-ray diffractometry, and the results showed that silver nanoparticles uniformly covered the material surface, while graphene was wrapped in a layer of bacterial cellulose. This composite film was conductive and produced a weak current, and it generated heat when a voltage was applied. This allowed it to accelerate wound cell migration and promote wound healing. In addition, AgNPs immobilized on the surface released Ag+, which generated a large number of oxidizing free radicals that killed and bacteria. The in vitro cytotoxicity tests showed that the Ag-pDA/BC (rGO) composite film has excellent biocompatibility, giving it good application prospects for wound dressings.

An Adaptive Monitoring Scheme for Automatic Control of Anaesthesia in dynamic surgical environments based on Bispectral Index and Blood Pressure.

During surgical procedures, bispectral index (BIS) is a well-known measure used to determine the patient's depth of anesthesia (DOA). However, BIS readings can be subject to interference from many factors during surgery, and other parameters such as blood pressure (BP) and heart rate (HR) can provide more stable indicators. However, anesthesiologist still consider BIS as a primary measure to determine if the patient is correctly anaesthetized while relaying on the other physiological parameters to monitor and ensure the patient's status is maintained. The automatic control of administering anesthesia using intelligent control systems has been the subject of recent research in order to alleviate the burden on the anesthetist to manually adjust drug dosage in response physiological changes for sustaining DOA. A system proposed for the automatic control of anesthesia based on type-2 Self Organizing Fuzzy Logic Controllers (T2-SOFLCs) has been shown to be effective in the control of DOA under simulated scenarios while contending with uncertainties due to signal noise and dynamic changes in pharmacodynamics (PD) and pharmacokinetic (PK) effects of the drug on the body. This study considers both BIS and BP as part of an adaptive automatic control scheme, which can adjust to the monitoring of either parameter in response to changes in the availability and reliability of BIS signals during surgery. The simulation of different control schemes using BIS data obtained during real surgical procedures to emulate noise and interference factors have been conducted. The use of either or both combined parameters for controlling the delivery Propofol to maintain safe target set points for DOA are evaluated. The results show that combing BIS and BP based on the proposed adaptive control scheme can ensure the target set points and the correct amount of drug in the body is maintained even with the intermittent loss of BIS signal that could otherwise disrupt an automated control system.