Multifunctional flexible contact lens for eye health monitoring using inorganic magnetic oxide nanosheets.

As a non-invasive innovative diagnosis platform, advanced flexible contact lenses can dynamically monitor vital ocular indicators, spot abnormalities and provide biofeedback guidance for real-time diagnosis and rehabilitation tracking of chronic eye diseases. However, most of the state-of-the-art reported contact lenses either can only monitor a single indicator at a time or realize multifunctional integration based on multiple materials. Herein, we developed a flexible multifunctional contact lens based on inorganic γ-Fe2O3@NiO magnetic oxide nanosheets, which can be attached conformally and seamlessly to the eyeball to simultaneously monitor glucose level in tears, eyeball movement, and intraocular pressure. The optimized contact lens has a reliable glucose detection limit (0.43 µmol), superior eye movement measurement accuracy (95.27%) and high intraocular pressure sensitivity (0.17 MHz mmHg- 1). This work presents a concept in the biochemical and biophysical integrated sensing of ocular signals using contact lens via an innovative material, and provides a personalized and efficient way for health management.

Snowflake-inspired and blink-driven flexible piezoelectric contact lenses for effective corneal injury repair.

The cornea is a tissue susceptible to various injuries and traumas with a complicated cascade repair process, in which conserving its integrity and clarity is critical to restoring visual function. Enhancing the endogenous electric field is recognized as an effective method of accelerating corneal injury repair. However, current equipment limitations and implementation complexities hinder its widespread adoption. Here, we propose a snowflake-inspired, blink-driven flexible piezoelectric contact lens that can convert mechanical blink motions into a unidirectional pulsed electric field for direct application to moderate corneal injury repair. The device is validated on mouse and rabbit models with different relative corneal alkali burn ratios to modulate the microenvironment, alleviate stromal fibrosis, promote orderly epithelial arrangement and differentiation, and restore corneal clarity. Within an 8-day intervention, the corneal clarity of mice and rabbits improves by more than 50%, and the repair rate of mouse and rabbit corneas increases by over 52%. Mechanistically, the device intervention is advantageous in blocking growth factors' signaling pathways specifically involved in stromal fibrosis whilst preserving and harnessing the signaling pathways required for indispensable epithelial metabolism. This work put forward an efficient and orderly corneal therapeutic technology utilizing artificial endogenous-strengthened signals generated by spontaneous body activities.

Effective Orthodontic Tooth Movement via an Occlusion-Activated Electromechanical Synergistic Dental Aligner.

Malocclusion is a prevalent dental health problem plaguing over 56% worldwide. Mechanical orthodontic aligners render directional teeth movement extensively used for malocclusion treatment in the clinic, while mechanical regulation inefficiency prolongs the treatment course and induces adverse complications. As a noninvasive physiotherapy, an appropriate electric field plays a vital role in tissue metabolism engineering. Here, we propose an occlusion-activated electromechanical synergistic dental aligner that converts occlusal energy into a piezo-excited alternating electric field for accelerating orthodontic tooth movement. Within an 18-day intervention, significantly facilitated orthodontic results were obtained from young and aged Sprague-Dawley rats, increasing by 34% and 164% in orthodontic efficiency, respectively. The different efficiencies were attributed to age-distributed periodontal tissue status. Mechanistically, the electromechanical synergistic intervention modulated the microenvironment, enhanced osteoblast and osteoclast activity, promoted alveolar bone metabolism, and ultimately accelerated tooth movement. This work holds excellent potential for personalized and effective treatment for malocclusions, which would vastly reduce the suffering of the long orthodontic course.

A programmable and skin temperature-activated electromechanical synergistic dressing for effective wound healing.

Mechanical regulation and electric stimulation hold great promise in skin tissue engineering for manipulating wound healing. However, the complexity of equipment operation and stimulation implementation remains an ongoing challenge in clinical applications. Here, we propose a programmable and skin temperature-activated electromechanical synergistic wound dressing composed of a shape memory alloy-based mechanical metamaterial for wound contraction and an antibacterial electret thin film for electric field generation. This strategy is successfully demonstrated on rats to achieve effective wound healing in as short as 4 and 8 days for linear and circular wounds, respectively, with a statistically significant over 50% improvement in wound closure rate versus the blank control group. The optimally designed electromechanical synergistic stimulation could regulate the wound microenvironment to accelerate healing metabolism, promote wound closure, and inhibit infection. This work provided an effective wound healing strategy in the context of a programmable temperature-responsive, battery-free electromechanical synergistic biomedical device.

Chemical characterization and toxicity assessment of fine particulate matters emitted from the combustion of petrol and diesel fuels.

Fuel consumption is one of the major contributors to air pollution worldwide. Plenty of studies have demonstrated that the diesel and petrol exhaust fine particulate matters (FPMs) are associated with increases of various diseases. However, the influences of different fuel types and their chemical components on toxicity have been less investigated. In this study, four kinds of fuels that widely used in China were burned in a laboratory simulation, and the FPMs were collected and analyzed. Transmission electron microscopy showed that black carbon was mainly soot with a dendritic morphology. For light diesel oil, marine heavy diesel oil, 93 octane petrol and 97 octane petrol diesel oil, the emission factors of FPMs were 3.05±0.29, 3.21±0.54, 2.36±0.33, and 2.28±0.25g/kg fuel, respectively. And the emission factors for the "16 US EPA" PAHs of FPM were 0.45±0.20, 0.80±0.22, 1.00±0.20, and 1.05±0.19mg/g FPMs, respectively. Fe is the most abundant metal in these FPMs, and the emission factors of FPMs were 2.58±1.70, 4.45±0.11, 8.18±0.58, and 9.24±0.17mg/g FPMs, respectively. We ranked the cytotoxicity of the FPMs emission from fuels combustion: marine heavy diesel oil>97 octane petrol>93 octane petrol>light diesel oil, and the genotoxicity of FPMs emission from fuels combustion: marine heavy diesel oil>light diesel oil>93 octane petrol>97 octane petrol. Significant correlations were found between PAH concentrations and reactive oxygen species (ROS) generation. Our results demonstrated that fuels exhaust FPMs have strong association with ROS activity, cytotoxicity and genotoxicity. These results indicated that fuels exhaust FPMs pose a potentially serious health, and emphasized the importance of assessing the health risks posed by the particulate pollutants in vehicle exhausts.