No abstract

Low level laser therapy is widely used to relieve pain and inflammation, and to restore cellular functions. The photons of light are absorbed by mitochondria in cells, leading to an increase in the production of adenosine triphosphate (ATP), nitric oxide release, blood flow, and reactive oxygen species (ROS). This study proposed the use of a laser diode array at 808 nm to stimulate the proliferation and to activate the functions of dermal papilla cells, which were an important part of the hair growth cycle. These cells were isolated from human hair follicles and were exposed to 808 nm light at various doses from 0.5, 1, 2.5, 4, and 6 J/cm. The rate of cell proliferation and the gene expression profile of dermal papilla cells were investigated and compared with the control in which the cells did not received any light treatment. The growth curves of the dermal papilla cells were used to determine the specific growth rates. Higher specific growth rates were observed in the cells exposed to laser at doses higher than 0.5 J/cm. The effect of the laser light treatment on several gene markers, specifically for dermal papilla cells, was evaluated using real-time polymerase chain reaction (qPCR). Our result shows that collagen type 1 (Col1), alkaline phosphatase (Alp), and versican (Vcan) did not increase when the cells were irradiated by the laser light. Interestingly, sex determining region y-box 2 (Sox2) gene was up-regulated when 0.5 J/cm, and 1 J/cm light was used, while an increase in the level of fibroblast growth factor 7 (Fgf7) gene was observed with light irradiation at 0.5 J/cm, 1 J/cm, 2.5 J/cm, and 4 J/cm. Too high irradiation dose was shown to yield no effect on the gene expression of dermal papilla cells.

The computational optimization of irradiance distribution uniformity has been conducted in several studies to obtain the evenness of photoresponses on an irradiated surface using light-emitting-diode (LED) arrays. However, there has been little discussion on the precision of predictive simulations. This study aims to validate the simulated irradiance predicted by a mathematical model on the working area of a six-well plate and investigate the spatial consistency of the photobleaching of methylene blue and IR-820 photosensitizers on the bottom of the different wells illuminated by using the local-search-optimized LED configurations. The validation signified the negative deviation of both the measured irradiance and irradiance uniformity as compared to the simulated data. Despite the coefficients of variation observed as low as 1.9% and 7.4% for red-light and infrared irradiance, respectively, the photobleaching responses were found to be spatially diverse. The implications of this study are opportunities for further enhancements to the predictability of the simulations for the design of prospective illumination setups.

The degradation of drugs within endolysosomes has been widely addressed as a cause of poor bioavailability. One of the strategies to allow molecules to escape from a destructive fate is to introduce a photosensitizing moiety into a drug carrier enabling the permeabilization of endosomes and endolysosomes upon irradiation. This paper presents an alternative delivery nanosystem composed of cost-effective soybean phosphatides mixed with IR-820, a near-infrared (NIR) sensitizer, to load various active compounds and trigger an endolysosomal escape with a low cytotoxic effect. Methods: IR-820-incorporated phosphatides-based nanoparticles were formulated using a thinfilm hydration method to encapsulate different molecular probes and a drug model. The nanoparticles were characterized in vitro using dynamic light scattering, transmission electron microscopy, as well as ultraviolet-visible and fluorescence spectroscopy techniques. The NIR-corresponding generation of the photochemical products, the content release, and the cytotoxicity toward the HaCaT keratinocyte cell line were evaluated. The cellular internalization and endolysosomal escape were monitored using a cytochemical marker and fluorescent probes with a colocalization analysis. Results: The IR-820-combined nanoparticles revealed the NIR-triggered changes in the singlet oxygen presence, nanoparticle architecture, and release rate without being cytotoxic. Additionally, the nanoplatform appeared to enhance cellular uptake of the macromolecules. The localization of the cytochemical marker and the colocalization analysis on the fluorescence signals of the encapsulated fluorophore and the lysosome-labeling reporter implied the transient endolysosomal escape of the cargo within the HaCaT cells after NIR irradiation. Conclusion: The inclusion of IR-820 into a soybean-phosphatides base ingredient provides NIR responsiveness, particularly the endolysosomal escape of the payload, to the formulated nanoparticles, while preserving the beneficial properties as a drug carrier. This alternative delivery nanomedicine system has future potential to provide high bioavailability of cytosolic drugs utilizing time-and spatial-controllable NIR triggerability as well as the synergistic therapeutic effects with NIR-biomodulation.