Integration of electrotaxis and durotaxis in cancer cells: Subtle nonlinear responses to electromechanical coupling cues.

Cells in living organisms live in multiphysics-coupled environments. There is growing evidence indicating that both exogenous electric field (EEF) and extracellular stiffness gradient (ESG) can regulate directional movement of cells, which are known as electrotaxis and durotaxis, respectively. How single cells respond to the ubiquitous electromechanical coupling cues, however, remains mysterious. Using microfluidic chip-based methodology and finite element-based electromechanical coupling design strategies, we develope an electromechanical coupling microchip system, enabling us to quantitatively investigate polarization and directional migration governed by EEF and ESG at the single cell level. It is revealed that both of electrotaxis and durotaxis nonlinearly depend on the physiological EEF and ESG, respectively. Specific combinations of EEF and ESG can subtly modify the polarization states of single cells and thus induce hyperpolarization and depolarization. Cells can integrate electrotaxis and durotaxis in response to multi-cue microenvironments via subtle mechanisms involving cooperation and competition during cellular electrosensing and mechanosensing. The work offers a platform for quantifying migration and polarization of cells driven by electromechanical cues, which is essential not only for elucidating physiological and pathological processes like embryo development, and invasion and metastasis of cancer cells, but for manipulating cell behaviors in a controllable and programmable fashion.

Activation of peroxymonosulfate by Fe-N complexes embedded within SBA-15 for removal of organic contaminants via production of singlet oxygen.

Persulfates are recognized as promising oxidants and an alternative to Fenton reaction for water treatment. However, activation methods in hand restrict the practical application. Herein, we explore the possibility of Fe-N complexes being a catalyst for persulfate activation for the first time. The catalyst denoted as Fe-Im-SBA was synthesized from ferric chloride, imidazole, and SBA-15 at high temperature. The internal pore structure of Fe-Im-SBA was maintained well; Fe, N and C elements are evenly distributed on the catalyst. This catalyst presents an extraordinarily catalytic activity for Rh B removal by PMS activation with a removal rate of Rh B that reached up to 97.0% in the first 5 min. It also performed well in a wide pH range with complete removal of Rh B in pH ranged from 0.5 to 10, suggesting the stability of this catalyst in both acidic and alkaline conditions. It also showed high adaptability to degrade different kinds of pollutants, which could give an attractive advantage of Fe-Im-SBA for environmental implications. Through X-ray absorption spectroscopies analysis, it shows that the active sites of Fe-Im-SBA are composed of Fe-N4 sites and Fe2-N2 sites. 1O2 were proved to generate in the Fe-Im-SBA/PMS system and serve as the major ROS. Meanwhile, graphitic carbon can accelerate the transfer of electrons, which may also be the reason for its high catalytic performance.

Efficient removal of antibiotics in a fluidized bed reactor by facile fabricated magnetic powdered activated carbon.

Powdered activated carbons (PACs) with micrometer size are showing great potential for enabling and improving technologies in water treatment. The critical problem in achieving practical application of PAC involves simple, effective fabrication of magnetic PAC and the design of a feasible reactor that can remove pollutants and recover the adsorbent efficiently. Herein, we show that such materials can be fabricated by the combination of PAC and magnetic Fe3O4 with chitosan-Fe hydrogel through a simple co-precipitation method. According to the characterization results, CS-Fe/Fe3O4/PAC with different micrometers in size exhibited excellent magnetic properties. The adsorption of tetracycline was fast and efficient, and 99.9% removal was achieved in 30 min. It also possesses good usability and stability to co-existing ions, organics, and different pH values due to its dispersive interaction nature. Finally, the prepared CS-Fe/Fe3O4/PAC also performed well in the fluidized bed reactor with electromagnetic separation function. It could be easily separated by applying a magnetic field and was effectively in situ regenerated, indicating a potential of practical application for the removal of pollutants from water.