Photosensitized and Photothermal Stimulation of Cellular Membranes by Organic Thin Films and Nanoparticles

Abstract

Conjugated polymers are increasingly exploited for biomedical applications. In this work, we explored the optical characteristics of conjugated polymers of variable chemical structures at multiple levels relevant to biological interfacing, from fluorescence yield to their influence on cellular membrane potential. We systematically compared the performance of conjugated polymer as cast thin films and as nanoparticles stabilized with amphiphilic polyethylene glycol-poly lactic acid-co-glycolic acid (PEG-PLGA). We assessed in both the dark and under illumination the stability of key optoelectronic properties in various environments, including air and biologically relevant physiological saline solutions. We found that photoreduction of oxygen correlates with nanoparticle and film degradation in physiologically relevant media. Using patch-clamp recordings in cell lines and primary neurons, we identified two broad classes of membrane potential response, which correspond to photosensitizer- and photothermal-mediated effects. Last, we introduced a metric named OED50 (optical energy for 50% depolarization), which conveys the phototoxic potency of a given agent and thereby its operational photo-safety profile.

Acoustic chip for rapid label-free early-stage detection of rare leukemic cells

“…This technique, known as polarisation-resolved differential phase contrast (pDPC) microscopy, can be easily integrated with fluorescence microscopy. Furthermore, OLEDs offer significant advantages for our application due to their ability to achieve sub-millisecond control of illumination [10], [11]. This rapid time resolution allows for precise synchronization of light pulses with acoustic manipulation within the microfluidic channel, a technique known as stroboscopic illumination, potentially enabling us to probe the dynamic behavior of rare cells at high temporal resolution.…”

Semiconducting Polymer Nanoporous Thin Films as a Tool to Regulate Intracellular ROS Balance in Endothelial Cells

“…43,44 From the abovementioned study cases, it clearly emerges how the structural engineering of the semiconducting polymer material, influenced by both chemical and physical parameters, plays a key role in the modulation of photophysical processes and intracellular ROS concentration, and it will ultimately determine their most successful applications in the redox medicine field. 45,46 However, in vivo photostimulation as a clinical treatment approach suffers from low photoelectrochemical yield due to the significant absorption of optical excitation by skin layers and the thermalization of the absorbed energy. 47 To address this limitation, the development of materials with a smaller bandgap or nanomaterials with better photon-to-ROS conversion yield is necessary and actively searched.…”

Conjugated polymer nanoparticles with tunable antibacterial photodynamic capability

“…2 In addition, the conjugated polymer chemical structure can be refined to achieve greater ROS/heat generation capabilities and to enhance water dispersibility, whilst enabling greater targetability against microorganisms. 2 The commercially available conjugated polymer poly(2.5di(hexyloxy)cyanoterephthalylidene) (CN-PPV) has been successfully explored for fluorescence bioimaging 13 and has potential applications as a photosensitizer 14 due to its useful optical features. The optical properties of such materials are not only highly dependent on the environment in which they are dispersed (such as solvent polarity and nanoparticle forming agent composition), but also on the nanoparticle preparation settings.…”