Uncontrollable hemorrhage from deep, narrow wounds poses a critical threat to life, as locating the bleeding arteries in such areas is challenging. Rapid bleeding control remains a significant challenge in pre-hospital care. Herein, an injectable hemostatic device filled with disc-like PVA sponges is developed for this objective. The pristine PVA sponge is strung as a necklace-structured sponge loaded in a foldable injector. With a novel retraction mechanism, this self-designed injector precisely deploys hemostatic sponges to deep bleeding sites, surpassing the XStat TM injector in design innovation. The PVA sponges' high porosity and unique porous structure allowed it for rapid shape recovery (<30 s) and good compressive strength. In the punctured wound, the swollen PVA sponges exert high compression to close the bleeding artery, resulting in fast-bleeding control. In the pig groin femoral artery injury model, the PVA sponge treatment resulted in a 100% survival rate during a 2-h hemostasis period, compared to a 33.3% survival rate in the cotton gauze control group. In addition, it can be easily taken out by a simple pulling. The easily applicable and removable necklace-structured PVA sponge is a highly promising hemostat for punctured wounds.
Recently, developing facile, cheap, and efficient nano‑silver catalysts for the reduction of waste 4-nitrophenol (4-NP) to useful 4-aminophenol (4-AP) has attracted more and more attention. In this study, a facile mechanical foaming method was used to fabricate Ag/halloysite nanotubes/polyvinyl alcohol sponges (Ag/Hal/PVA) for enhanced degradation of 4-NP. It included the preparation, morphology and composition characterization, and catalytic performance test of Ag/Hal/PVA. The morphology and composition of Ag/Hal/PVA were characterized by field emission scanning electron microscopy , Fourier transform infrared spectra , Raman spectra , X-ray photoelectron spectroscopy, thermo-gravimetric analysis, and XRD, respectively. BET and UV–vis spectrum measurements were used to test the adsorption and catalytic performance of Ag/Hal/PVA for 4-NP. The results showed that silver nanoparticles (AgNPs) were evenly distributed in the Hal/PVA sponge. Moreover, halloysite nanotubes (Hal) greatly improved the specific surface area and the loading capacity for AgNPs of the sponge due to the hollow tubular structure of Hal. The specific surface area of the Ag/Hal/PVA was about 1.62 m 2 /g. The obtained Ag/Hal/PVA exhibited a good catalytic activity and the apparent rate constant was 0.297 min −1 , and a good stability up to 5 cycles without a significant loss of its catalytic activity. This study provided a facile strategy for the development of cheap Ag/Hal/PVA sponges for high efficient reduction of 4-NP, which has potential application in the filed water treatment
Surface-enhanced Raman scattering (SERS) has been widely applied in the field of food safety due to its exceptional molecular recognition capabilities. In this study, a simple method for preparing a flexible SERS substrate was designed for the ultrasensitive real-time detection of the banned drugs malachite green (MG) and crystal violet (CV). The substrate was prepared by patterned spraying of a superhydrophobic coating prepared from candle soot onto the surface of a poly(vinyl alcohol) (PVA) sponge, followed by simple Ag nanoparticle (Ag NP) deposition in the superhydrophilic region. The PVA sponge with special hydrophilicity can completely absorb the droplets to be measured within 1–5 s without additional drying treatment. And the Ag NPs aggregated by potassium iodide (KI) resulted in a significant enhancement of the Raman signal, enabling the substrate to realize the detection of MG and CV as low as 100 fg/mL (2.74 × 10–13 M) and 1 pg/mL (2.45 × 10–12 M), respectively, with a long lifetime (90 days). Thanks to the excellent mechanical properties of the flexible substrate, the substrate can realize the simultaneous detection of very small amounts of MG and CV on the surface of crayfish by simple wiping, which has great application prospects in the field of food safety and field inspection.
危险品化学品经营许可证（带存储）