A composite geopolymeric material was synthesized from Bayer red mud combined with granulated blast‐furnace slag. Thermal pretreatment was applied to improve the solubility of red mud in alkaline solution to promote geopolymerization. The dissolution efficiencies of alumina and silica reached a maximum when red mud was calcined at 800°C, resulting in the highest compressive strength of binders. It was demonstrated that a higher solubility of calcined red mud led to a higher strength of the composite binders. The characteristic microstructures of hydration products were studied to illustrate the geopolymerization process by XRD, FTIR and SEM. The results showed that aluminosilicates were dissolved in the alkaline solution to form nanostructural particulates during the early dissolution process, and then accumulated to form highly dense geopolymeric matrices through solidification reaction. The coexistence of geopolymer and C–(A)–S–H is suggested to contribute to the good performance of the composite binders.

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In this work, the effects of curcumin on the viability, morphology, and nanomechanics of SH-SY5Y neuronal cells were investigated using a conventional cell viability test kit (CCK-8) and sophisticated AFM imaging and force measurement techniques. CCK-8 tests show that SH-SY5Y neuronal cells have a dose–response to curcumin in terms of viability that is dependent on the exposure durations. When exposed to a maximum dosage of 32 μg/mL used in the present study for 4 h, 24 h, and 48 h, the cell viability dropped to 73.4 ± 4.5%, 9.1 ± 3.2%, and 2.5 ± 1.2% of the control, correspondingly. AFM studies show that curcumin can induce the disappearance of synapses of the cells and the change of biomechanics. After exposure for 24 h at the concentration of 16 μg/mL, the viscous deformation of the cells decreased from 2.15 ± 0.02 to 1.58 ± 0.03 (×10–15 N·m), the elastic deformation increased from 1.26 ± 0.04 to 1.72 ± 0.07 (×10–15 N·m), and adhesion work decreased from 0.56 ± 0.07 to 0.39 ± 0.04 (×10–16 N·m). The morphological and mechanical changes obtained using AFM can be interpreted from optically observed cellular structural changes. The present study provides insights into the effects of curcumin on neuronal cells from both biological and biophysical aspects, which can help more comprehensively understand the interactions between curcumin and SH-SY5Y cells. The demonstrated techniques can be potentially used to assess the efficacy of bioactive constituents on cells or help screen drugs.

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