Polarity‐Dominated Stable N97 Respirators for Airborne Virus Capture Based on Nanofibrous Membranes

Characterization and Biological Evaluation of Composite Nanofibrous Membranes Prepared from Hemp Salmon (Oncorhynchus keta) Skin Collagen

Aquatic collagen, a natural macromolecule protein with excellent biocompatibility, has attracted attention in the field of medical materials. Compared to mammalian collagen, aquatic collagen offers unique advantages, including the absence of zoonotic disease risks and religious concerns. In this study, salmon skin collagen nanofiber membrane (GS) was prepared by electrostatic spinning. Then, skin collagen was combined with silk sericin (SS) and sodium hyaluronate (HA) to fabricate composite collagen nanofiber membrane (GF) using electrostatic spinning technology. GF membranes were further cross-linked (GFL) for use in a mouse wound healing model. The physicochemical properties and biocompatibility of GS, GF, and GFL were evaluated. FTIR analysis revealed that GFL exhibited a more stable secondary structure compared to GS and GF. DSC and TGA results indicated that GFL had the highest thermal stability, followed by GF. Cytotoxicity tests confirmed that GS, GF, and GFL were non-cytotoxic, with GF showing the highest cell viability rate of 175.23 ± 1.77%. In the wound healing model, GFL group achieved nearly complete healing by day 14 (98 ± 0.1%), compared to 76.04 ± 0.01% in the blank group. Measurement of TGF-β1 and VEGF levels in the healing tissue on day 14 indicated that the GFL group had progressed to the late stage of healing, whereas the blank group remained in the early stage. These results suggest that GFL holds significant potential as a medical biomaterial for wound healing applications.

One Droplet toward Efficient Alcohol Detection Using Femtosecond Laser Textured Micro/Nanostructured Surface with Superwettability

Alcohol with different concentrations is commonly used in food, industry, and medicine fields all over the world. However, current methods for detecting alcohol concentration are restricted to large sample consumption, additional senergy consuming, or complex operations. Here, inspired by superwettability of lotus leaves, a superhydrophobic and superorganophilic surface is designed on the polydimethylsiloxane (PDMS) for one droplet efficient alcohol detection, which is prepared via femtosecond laser direct writing technology. Meanwhile, the contact angles of droplets with various alcohol concentrations on the laser-treated PDMS (LTP) surface are different. Based on the above characteristic, alcohol concentration through contact angle measurement without any external energy is directly detected, which is simple and efficient. Furthermore, it is worth noting that the LTP surface remains stable wettability after 1000 water-ethanol cycles and 300 days tests in air, indicating strong surface repeatability and stability. Significantly, the LTP surface has a broad potential application in one droplet detecting alcohol concentration, fake or genuine wine, and alcohol molecules. This work provides a new strategy to fabricate a superwetting surface for efficient one droplet alcohol detection.

Heterogeneous Electrospinning Nanofiber Membranes with pH-regulated Ion Gating for Tunable Osmotic Power Harvesting

Biological ion channels existing in organisms are critical for many biological processes. Inspired by biological ion channels, the heterogeneous electrospinning nanofiber membranes (HENM) with functional ion channels are constructed by electrospinning technology. The HENM successfully realizes ion-gating effects, which can be used for tunable energy conversions. Introduction of pyridine and carboxylic acid groups into the HENM plays an important role in generating unique and stable ion transport behaviors, in which gates become alternative states of open and close, responding to symmetric/asymmetric pH stimulations. Then we used the HENM to convert osmotic energy into electric energy which reach a maximum value up to 12.34 W m^-2 and the output power density of HENM-based system could be regulated by ion-gating effects. The properties of the HENM provide widespread potentials in application of smart nanofluidic devices, energy conversion, and water treatment.

Saving 80% Polypropylene in Facemasks by Laser-Assisted Melt-Blown Nanofibers

The ongoing coronavirus (COVID-19) pandemic requires enormous production of facemasks and related personal protection materials, thereby increasing the amount of nondegradable plastic waste. The core material for facemasks is melt-blown polypropylene (PP) fiber. Each disposable facemask consumes ∼0.7 g of PP fibers, resulting in annual global consumption and disposal of more than 1 150 000 tons of PP fibers annually. Herein, we developed a laser-assisted melt-blown (LAMB) technique to manufacture PP nanofibers with a quality factor of 0.17 Pa^-1 and significantly reduced the filter's weight. We demonstrated that a standard surgical facemask could be made with only 0.13 g of PP nanofibers, saving approximately 80% of the PP materials used in commercial facemasks. Theoretical analysis and modeling were also conducted to understand the LAMB process. Importantly, nanofibers can be easily scaled up for mass production by upgrading traditional melt blown line with scanning laser-assisted melt-blown (SLAMB).