Tailoring ZnO nanowire crystallinity and morphology for label-free capturing of extracellular vesicles.

Zinc oxide (ZnO) nanowires have shown their potential in isolation of cancer-related biomolecules such as extracellular vesicles (EVs), RNAs, and DNAs for early diagnosis and therapeutic development of diseases. Since the function of inorganic nanowires changes depending on their morphology, previous studies have established strategies to control the morphology and have demonstrated attainment of improved properties for gas and organic compound detection, and for dye-sensitized solar cells and photoelectric conversion performance. Nevertheless, crystallinity and morphology of ZnO nanowires for capturing EVs, an important biomarker of cancer, have not yet been discussed. Here, we fabricated ZnO nanowires with different crystallinities and morphologies using an ammonia-assisted hydrothermal method, and we comprehensively analyzed the crystalline nature and oriented growth of the synthesized nanowires by X-ray diffraction and selected area electron diffraction using high resolution transmission electron microscopy. In evaluating the performance of label-free EV capture in a microfluidic device platform, we found both the crystallinity and morphology of ZnO nanowires affected EV capture efficiency. In particular, the zinc blende phase was identified as important for crystallinity, while increasing the nanowire density in the array was important for morphology to improve EV capture performance. These results highlighted that the key physicochemical properties of the ZnO nanowires were related to the EV capture performance.

Alterations of mineralized matrix by lead exposure in osteoblast (MC3T3-E1) culture.

The present study investigated the effect of lead (Pb) on bone ultrastructure and chemistry using an in vitro bone model. MC3T3-E1 preosteoblasts were differentiated and treated with lead acetate at 0.4, 2, 10, and 50 µM. No abnormalities in either cell growth or bone nodule formation were observed with the treated dose of lead acetate. However, Pb treatments could significantly increase Pb accumulation in differentiated osteoblast cultures and upregulate expression of Divalent metal transporter 1 (Dmt1) in a dose dependent manner. Pb treatments also altered the expression of osteogenic genes, including secreted phosphoprotein 1, osteocalcin, type I collagen, and osteoprotegerin. Moreover, in mineralized osteoblast cultures, Pb was found to be mainly deposited as Pb salts and oxides, respectively. Ultrastructure analysis revealed Pb localizing with calcium and phosphorus in the mineralized matrix. In mineralizing osteoblast cells, Pb was found in the intracellular calcified vesicles which is one of the bone mineralization mechanisms. Pb was also present in mineral deposits with various shapes and sizes, such as small and large globular or needle-like mineral deposits representing early to mature stages of mineral deposits. Furthermore, Pb was found more in the globular deposits than the needle shaped mineral crystals. Taken together, our observations revealed how Pb incorporates into bone tissue, and showed a close association with bone apatite.

Piezoelectric-Induced Triboelectric Hybrid Nanogenerators Based on the ZnO Nanowire Layer Decorated on the Au/polydimethylsiloxane-Al Structure for Enhanced Triboelectric Performance.

Here, we demonstrate a novel device structure design to enhance the electrical conversion output of a triboelectric device through the piezoelectric effect called as the piezo-induced triboelectric (PIT) device. By utilizing the piezopotential of ZnO nanowires embedded into the polydimethylsiloxane (PDMS) layer attached on the top electrode of the conventional triboelectric device (Au/PDMS-Al), the PIT device exhibits an output power density of 50 µW/cm2, which is larger than that of the conventional triboelectric device by up to 100 folds under the external applied force of 8.5 N. We found that the effect of the external piezopotential on the top Au electrode of the triboelectric device not only enhances the electron transfer from the Al electrode to PDMS but also boosts the internal built-in potential of the triboelectric device through an external electric field of the piezoelectric layer. Furthermore, 100 light-emitting diodes (LEDs) could be lighted up via the PIT device, whereas the conventional device could illuminate less than 20 LED bulbs. Thus, our results highlight that the enhancement of the triboelectric output can be achieved by using a PIT device structure, which enables us to develop hybrid nanogenerators for various self-power electronics such as wearable and mobile devices.