Wearable Photoelectric Fingertip Force Sensing System Based on Blood Volume Changes without Sensory Interference.

Monitoring the force of fingertip manipulation without disturbing the natural sense of touch is crucial for digitizing the skills of experienced craftsmen. However, conventional force sensors need to be put between the skin and the objects, which affects the natural sense of the skin. Here, we proposed a fingertip force sensing method based on changes of blood volume and designed a wearable photoelectric fingertip force sensing system (PFFS) for digitalization of traditional Chinese medicine (TCM) pulse diagnosis. The PFFS does not interfere with the fingertips' tactile sense while detecting fingertip force. This PFFS detects the change of blood volume in fingertip by photoelectric plethysmography and can obtain the change of output current under different fingertip forces. We also studied the effect of various factors on PFFS output signals, including emission lights of different wavelengths, ambient temperature, and the user's heartbeat artifact. We further established the relationship between the change of blood volume and fingertip force by combining experimental and theoretical methods. Moreover, we demonstrated the feasibility of the PFFS to detect fingertip forces under commonly used conditions in TCM pulse diagnosis without sensory interference. This PFFS also shows promise for perceiving the viscosity of objects and recognizing gestures in human-computer interaction. This work paves the way for the digitalization of fingertip forces during TCM pulse diagnosis and other fingertip forces under natural conditions.

Alnustone inhibits Streptococcus pneumoniae virulence by targeting pneumolysin and sortase A.

Streptococcus pneumoniae (S. pneumoniae) is a major Gram-positive opportunistic pathogen that causes pneumonia, bacteremia, and other fatal infections. This bacterium is responsible for more deaths than any other single pathogen in the world. Inexplicably, these symptoms persist despite the administration of effective antibiotics. Targeting pneumolysin (PLY) and sortase A (SrtA), the major virulence factors of S. pneumoniae, this study uncovered a novel resistance mechanism to S. pneumoniae infection. Using protein phenotype assays, we determined that the small molecule inhibitor alnustone is a potent drug that inhibits both PLY and SrtA. As essential virulence factors of S. pneumoniae, PLY and SrtA play a significant role in the occurrence of infection. Furthermore, evaluation using PLY-mediated hemolysis assay demonstrated alunstone had the potential to interrupt the haemolytic activity of PLY with treatment alunstone (4 µg/ml). Co-incubation of S. pneumoniae D39 SrtA with small-molecule inhibitors decreases cell wall-bound Nan A (pneumococcal-anchored surface protein SrtA), inhibits biofilm formation, and reduces biomass significantly. The protective effect of invasive pneumococcal disease (IPD) on murine S. pneumoniae was demonstrated further. Our study proposes a comprehensive bacteriostatic mechanism for S. pneumoniae and highlights the significant translational potential of targeting both PLY and SrtA to prevent pneumococcal infections. Our findings indicate that the antibacterial strategy of directly targeting PLY and SrtA with alnustone is a promising treatment option for S. pneumoniae and that alnustone is a potent inhibitor of PLY and SrtA.

Physicochemical Properties and Cellular Uptake of Astaxanthin-Loaded Emulsions.

Astaxanthin, a natural pigment carotenoid, is well known for its potential benefits to human health. However, its applications in the food industry are limited, due to its poor water-solubility and chemical instability. Six different emulsifiers were used to prepare astaxanthin-loaded emulsions, including whey protein isolate (WPI), polymerized whey protein (PWP), WPI-lecithin, PWP-lecithin, lecithin, and Tween20. The droplet size, zeta potential, storage stability, cytotoxicity, and astaxanthin uptake by Caco-2 cells were all investigated. The results showed that the droplet size of the emulsions ranged from 194 to 287 nm, depending on the type of emulsifier used. The entrapment efficiency of astaxanthin was as high as 90%. The astaxanthin-loaded emulsions showed good physicochemical stability during storage at 4 °C. The emulsifier type had a significant impact on the degradation rate of astaxanthin (p < 0.05). Cellular uptake of astaxanthin encapsulated into the emulsions was significantly higher than free astaxanthin (p < 0.05). Emulsion stabilized with WPI had the highest cellular uptake of astaxanthin (10.0 ± 0.2%), followed, in order, by that with PWP (8.49 ± 0.1%), WPI-lecithin (5.97 ± 0.1%), PWP-lecithin (5.05 ± 0.1%), lecithin (3.37 ± 0.2%), and Tween 20 (2.1 ± 0.1%). Results indicate that the whey protein-based emulsion has a high potential for improving the cellular uptake of astaxanthin.