Existing nanoscale chemical delivery systems target diseased cells over long, sustained periods of time, typically through one-time, destructive triggering. Future directions lie in the development of fast and robust techniques capable of reproducing the pulsatile chemical activity of living organisms, thereby allowing us to mimic biofunctionality. Here, we demonstrate that by applying programmed femtosecond laser pulses to robust, nanoscale liposome structures containing dopamine, we achieve sub-second, controlled release of dopamine--a key neurotransmitter of the central nervous system--thereby replicating its release profile in the brain. The fast delivery system provides a powerful new interface with neural circuits, and to the larger range of biological functions that operate on this short timescale.
Micromodification in bulk undoped polymethylmethacrylate (PMMA) by single focused (numerical aperture (NA) = 0.25), 1030-nm 250-fs laser pump pulses was explored by pump self-transmittance; optical, 3D-scanning confocal photoluminescence (PL); Raman micro-spectroscopy; and optical polarimetric and interferometric microscopy. Starting from the threshold pulse energy = 0.
We demonstrate that amplitude modulation of a high-peak-power femtosecond laser pulse allows to change fundamentally the frequency-angular structure (FAS) of the supercontinuum formed during the filamentation in both molecular and atomic gases. Particularly, modulation with a 4-hole mask forms an inverted pattern of conical emission (CE) with its predominance in the Stokes wing of the pulse spectrum. We explain this phenomenon as a joint effect of self-phase modulation and temporal pulse splitting of interfering beamlets formed by the modulating mask.
Breast cancer ranks as the second most widespread form of cancer globally. Currently, combination therapy is being actively employed in clinical practice to augment the efficiency of anticancer treatment. Hence, the objective of this study was to assess the therapeutic efficacy of a combination of femtosecond laser-based PDT utilizing two distinct photosensitizers (PSs), zinc phthalocyanine tetrasulfonate (ZnPcS4) and meso-tetrakis(4-N-methylpyridyl) porphine (TMPyP) in conjunction with doxorubicin chemotherapeutic agent, on mammary carcinomas experimentally induced in female mice using 7,12-dimethylbenz (a) anthracene (DMBA).
Attosecond observations of coherent electron dynamics in molecules and nanostructures can be achieved by combining conventional scanning tunneling microscopy (STM) with ultrashort femtosecond laser pulses. While experimental studies in the subcycle regime are under way, a robust strong-field theory description has remained elusive. Here we devise a model based on the strong-field approximation.
Traditional deep fluorescence imaging has primarily focused on red-shifting imaging wavelengths into the near-infrared (NIR) windows or implementation of multi-photon excitation approaches. Here, we combine the advantages of NIR and multiphoton imaging by developing a dual-infrared two-photon microscope to enable high-resolution deep imaging in biological tissues. We first computationally identify that photon absorption, as opposed to scattering, is the primary contributor to signal attenuation.
