Though, the pharmacological activity of curcumin inhibiting the proliferation of certain cancer cells in culture was demonstrated, its effect on early-stage modifications induced in cell mechanics influencing hereby cell growth and cell adhesion are still questionable. We investigate the morphology and the elastic properties of live cultured, non-malignant human mammalian epithelial cells (HMEC) and cancerous breast epithelial cells (MCF7), using atomic force microscopy (AFM). We describe the different behavior of the two similar cell lines under curcumin treatment and we use fluorescence microscopy to identify the microtubules as the cytoskeleton structures responding to curcumin. The first changes in the HMEC cell morphology are observed after already two hours incubation with curcumin. A six-hour long treatment leaves the MCF7 cells morphology non-affected, but the microtubules of HMEC cells disassemble and form a ring-like organization circumscribing the nuclear area. The observed morphological changes were correlated to modifications in cell's mechanics via elasticity force mapping measurements. Curcumin treatment modified elasticity of the HMEC cells increasing the cell's average Young's modulus two- to three-fold, especially in the cytoplasmic area. Contrariwise, a slight decrease in the Young's modulus was noticed for the MCF7 cells, as they become softer due to the action of curcumin. Chemotherapeutic drugs exert their effect via the perturbation of the dynamic instability of the microtubule, hence the cell specific perturbation induced by curcumin can help in future understanding of drug induced events on the cell behavior.

The purified photosynthetic reaction center protein (RC) from Rhodobacter sphaeroides R-26 purple bacteria was bound to porous silicon microcavities (PSiMc) either through silane-glutaraldehyde (GTA) chemistry or via a noncovalent peptide cross-linker. The characteristic resonance mode in the microcavity reflectivity spectrum red shifted by several nanometers upon RC binding, indicating the protein infiltration into the porous silicon (PSi) photonic structure. Flash photolysis experiments confirmed the photochemical activity of RC after its binding to the solid substrate. The kinetic components of the intraprotein charge recombination were considerably faster (τfast = 14 (±9) ms, τslow = 230 (±28) ms with the RC bound through the GTA cross-linker and only τfast = 27 (±3) ms through peptide coating) than in solution (τfast = 120 (±3) ms, τslow = 1387 (±2) ms), indicating the effect of the PSi surface on the light-induced electron transfer in the protein. The PSi/RC complex was found to oxidize the externally added electron donor, mammalian cytochrome c, and the cytochrome oxidation was blocked by the competitive RC inhibitor, terbutryne. This fact indicates that the specific surface binding sites on the PSi-bound RC are still accessible to external cofactors and an electronic interaction with redox components in the aqueous environment is possible. This new type of biophotonic material is considered to be an excellent model for new generation applications at the interface of silicon-based electronics and biological redox systems designed by nature.

The dorsal root ganglia contain a variety of sensory neurons that transduce somatic stimuli. Following peripheral nerve injury, sensory neurons have to adapt to a new environment in order to successfully promote their axonal elongation. Unsuccessful regeneration leads to post-traumatic neuropathies, such ataxia and pain-related behavior, which are often chronic and mostly resistant to current treatments. Understanding the cellular and molecular mechanisms leading to improved neurite re-growth is a major step to propose a new therapy for nerve repair. It has been demonstrated that a prior in vivo nerve injury enhances both peripheral and central axonal regeneration following a second injury. In vitro, the neurons conditioned by the first traumatism display a faster, elongated mode of neurite growth called regenerative growth. The neuronal growth cone is a highly motile mechanosensitive structure at the tip of the axon. Elasticity is a determining parameter of membrane mechanical properties and provides important information toward the health and function of the cell. Interestingly, it has been shown that membrane tension influences growth cones dynamics. We have investigated, using DIC and AFM, the morphology and the membrane mechanical properties of adult sensory neurons from mice DRG following left sciatic nerve injury.

Comparative studies on the nanomechanics of normal and malignant cells of the same type are of great importance as they can reveal new information about, and help understanding mechanisms of malignant transformation. In this work, we investigate the morphology and the elastic properties of live cultured, normal human mammalian epithelial cells (HMEC) and breast carcinoma epithelial cells (MCF7), using atomic force microscopy (AFM). We describe the different behaviour of the two similar cell lines under curcumin treatment. Up to a six-hour long treatment leaves the MCF7 cells morphology non-affected, but the microtubules of HMEC cells disassemble and form a ring-like organization circumscribing the nuclear area. The observed morphological changes were correlated to modifications in cell's mechanics via elasticity force-volume measurements. Curcumin treatment modified elasticity of the HMEC cells increasing dramatically the cell's average Young's modulus. Contrariwise, a slight decrease in the Young's modulus value was noticed for the MCF7 cells, as they become softer due to the action of curcumin. This different response of the malignant and non-malignant cells under the same treatment might be of high importance in developing follow-up therapy against breast cancer. Moreover, we also explore the effectiveness of paclitaxel on MCF7 cells. Although paclitaxel is used widely in the treatment of breast cancer, not all tumors respond to this drug, and the characteristics that distinguish resistant tumors from sensitive ones are not well defined.