Photocell-Based Optofluidic Device for Clogging-Free Cell Transit Time Measurements.

Measuring the transit time of a cell forced through a bottleneck is one of the most widely used techniques for the study of cell deformability in flow. It in turn provides an accessible and rapid way of obtaining crucial information regarding cell physiology. Many techniques are currently being investigated to reliably retrieve this time, but their translation to diagnostic-oriented devices is often hampered by their complexity, lack of robustness, and the bulky external equipment required.

Membrane Order Effect on the Photoresponse of an Organic Transducer.

Non-genetic photostimulation, which allows for control over cellular activity via the use of cell-targeting phototransducers, is widely used nowadays to study and modulate/restore biological functions. This approach relies on non-covalent interactions between the phototransducer and the cell membrane, thus implying that cell conditions and membrane status can dictate the effectiveness of the method. For instance, although immortalized cell lines are traditionally used in photostimulation experiments, it has been demonstrated that the number of passages they undergo is correlated to the worsening of cell conditions.

Membrane Targeted Azobenzene Drives Optical Modulation of Bacterial Membrane Potential.

Recent studies have shown that bacterial membrane potential is dynamic and plays signaling roles. Yet, little is still known about the mechanisms of membrane potential dynamics regulation-owing to a scarcity of appropriate research tools. Optical modulation of bacterial membrane potential could fill this gap and provide a new approach for studying and controlling bacterial physiology and electrical signaling.

Azobenzene photoisomerization probes cell membrane viscosity.

The viscosity of cell membranes is a crucial parameter that affects the diffusion of small molecules both across and within the lipid membrane and that is related to several diseases. Therefore, the possibility to measure quantitatively membrane viscosity on the nanoscale is of great interest. Here, we report a complete investigation of the photophysics of an amphiphilic membrane-targeted azobenzene (ZIAPIN2) and we propose its use as a viscosity probe for cell membranes.

Shedding Light on Thermally Induced Optocapacitance at the Organic Biointerface.

Photothermal perturbation of the cell membrane is typically achieved using transducers that convert light into thermal energy, eventually heating the cell membrane. In turn, this leads to the modulation of the membrane electrical capacitance that is assigned to a geometrical modification of the membrane structure. However, the nature of such a change is not understood.

Bringing Microbiology to Light: Toward All-Optical Electrophysiology in Bacteria.

The observation of neuron-like behavior in bacteria, such as the occurrence of electric spiking and extended bioelectric signaling, points to the role of membrane dynamics in prokaryotes. Electrophysiology of bacteria, however, has been overlooked for long time, due to the difficulties in monitoring bacterial bioelectric phenomena with those probing techniques that are commonly used for eukaryotes. Optical technologies can allow a paradigm shift in the field of electrophysiology of bacteria, as they would permit to elicit and monitor signaling rapidly, remotely, and with high spatiotemporal precision.

Sterilization of Semiconductive Nanomaterials: The Case of Water-Suspended Poly-3-Hexylthiophene Nanoparticles.

In this work, the feasibility of sterilizing a water suspension of poly-3-hexylthiophene nanoparticles (P3HT-NPs) is investigated using ionizing radiation, either γ-rays or high-energy electrons (e-beam). It is found that regardless of the irradiation source, the size, polydispersity, aggregation stability, and morphology of the NPs are not affected by the treatment. Furthermore, the impact of ionizing radiation on the physicochemical properties of NPs at different absorbed radiation doses (10-25 kGy) and dose rates (kGy time ) is evaluated through different spectroscopic techniques.

The Effect of an Intramembrane Light-Actuator on the Dynamics of Phospholipids in Model Membranes and Intact Cells.

The noncovalent intercalation of amphiphilic molecules in the lipid membrane can be exploited to modulate efficiently the physical status of the membrane. Such effects are largely employed in a range of applications, spanning from drug-delivery to therapeutics. In this context, we have very recently developed an intramembrane photo-actuator consisting of an amphiphilic azobenzene molecule, namely ZIAPIN2.