KEYWORDS: Laser irradiation, Fluorescence, Monte Carlo methods, Fluorescence intensity, Diffusion, Molecules, Data modeling, Gold nanoparticles, Time metrology, Pulsed laser operation
SignificanceResealing time based loading efficiency of optoporation is the key parameter for drug or gene delivery. This work describes a comparatively simple optical approach to directly measure the cell membrane resealing time of the gold nanoparticle mediated photoporation.AimTo establish a membrane potential detection optical system, which can provide a direct measurement of resealing time of the optoporated cells.ApproachVoltage sensitive dye has been used to label the gold nanoparticle covered cell before laser activation and the resealing time was estimated from the voltage change due to the fluorescence light intensity change before and after laser activation. The approach has been validated by the simulated data based on diffusion model and Monte Carlo simulation and the experimental data obtained from a flow cytometry analysis.ResultsThe measured resealing time after perforation varied from 28.6 to 163.8 s on Hela cells when the irradiation fluence was increased, with a correlation coefficient (R2) of 0.9938. This result is in agreement with the resealing time (1-2 min) of photothermal porated Hela cells measured by electrical impedance method. The intracellular delivery efficiency of extracellular macromolecular under the same irradiation fluence depends mainly on diffusion velocity rather than pore size.ConclusionThe method described here can be used to directly measure resealing time of optoporated cells for accurately estimating the loading efficiency on discovering the mechanism of optoporation.
Combining photodynamic therapy (PDT) and immunotherapy modalities has shown encouraging therapeutic efficacy against various metastasis cancers. Developing a functional nanoparticle for tumor-targeting and on-demand release of drug is still a major focus for advancing therapeutic approach. Herein, we assembled a β-cyclodextrin (β-CD) modified MMP-2 responsive peptide with a photosensitizer-loaded liposome to construct a tumor immune microenvironment and laser dual-triggered nano system (matrix metalloproteinase 2 (MMP-2) responsive peptide liposome, MR@Lip) for melanoma therapy. The β-CDs encapsulating SB-3CT were released due to the cleavage of the peptide substrate by MMP-2 which is highly expressed in tumor stroma. The localized released SB-3CT was kept in the stroma and inhibited the expression of MMP, down-regulating the soluble NKG2D ligands. The liposome loading photosensitizer Ce6 targeted and killed melanoma cells under laser irradiation, while induced the expression of NKG2D ligands and finally leading to an increase in sensitivity of A375 cells to NK cells. This study might provide novel insight into the development of a new nanomedicine to achieve programmed release of antitumor drugs and better integration of PDT and immune therapy for melanoma.
Although TiO2 can be used to effectively generate reactive oxygen species (ROS) for photodynamic application, its absorption in the ultraviolet range makes the excitation harmful to tissue. Based on the concept of a sensitized solar cell, TiO2 nanoparticles (NPs) are sensitized by linking with the photosensitizer, HMME, to form HMME-TiO2 nanocomposites (NCs) for demonstrating the photodynamic effects under the illumination of white light. The HMME-TiO2 NCs of different composition ratios are prepared for maximizing the generation of ROS and optimizing the inactivation effect of KB cells. The material characteristics and the ROS generation capability of the HMME-TiO2 NCs with the optimized combination ratio show their merits in a photodynamic process under white light irradiation. The application of such NCs to KB cell experiments results in a higher inactivation efficiency when compared to pure HMME of the same concentration.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.