Biocompatible Lipid‐Coated Persistent Luminescent Nanoparticles for In Vivo Imaging of Dendritic Cell Migration

Abstract

Dendritic cell (DC)‐based vaccines for immunotherapy have already achieved promising results in the last decade. To further improve current treatment protocols and enhance the therapeutic outcome, noninvasive in vivo tracking of DCs remains of crucial importance. Persistent luminescent nanoparticles (PLNPs) are inorganic materials which show an afterglow for hours after the optical excitation has ceased. If the afterglow is in the near‐infrared, the emission of injected particles can be tracked in vivo. However, stability and toxicity issues limit the use of bare PLNPs for biological applications. Therefore, appropriate surface functionalization is needed to improve their biocompatibility. In this study, it is demonstrated that near‐infrared light emitting LiGa5O8:Cr3+ nanoparticles can be functionalized with a biocompatible lipid coating which provides them with outstanding stability in biological media. In vitro experiments show efficient uptake, absence of cytotoxicity even at very high particle concentrations, and no adverse effects on the maturation potential of DCs. DCs labeled with lipid‐coated LiGa5O8:Cr3+ nanoparticles injected in mice can be imaged over days, confirming efficient in vivo migration to the popliteal lymph node. Together the results show that lipid coated LiGa5O8:Cr3+ nanoparticles possess excellent possibilities for further use in research and development of DC based vaccines.

Synthesis and Characterization of GdVO4:Nd Near-Infrared Phosphors for Optical Time-Gated In Vivo Imaging

“…Organic NIR emitting molecules such as ICG (indocyanine green) are currently used in surgery [2,3], but these organic fluorophores are limited in terms of stability and are only used for direct imaging. In a recently developed imaging method, persistent luminescent particles are used, which are charged optically outside the body and are then injected [4]. While these particles keep emitting light for a long time in vivo without any additional excitation, such particles can emit only a limited amount of light, determined by the number of electronic traps that can be filled upon excitation [5].…”

Surface Modified Persistent Luminescence Probes for Biosensing and Bioimaging: A Review

“…Reprinted with permission. [ 73 ] (C) Schematic illustration of the PLL‐modified PLNPs for tracking of the transplanted hMSCs in bleomycin (BLM)‐induced PF. Reprinted with permission.…”

“…reported that they used lipid‐coated LiGa 5 O 8 :Cr 3+ PLNPs to achieve in vivo visualization of dendritic cells (DCs) migration which were used for immunotherapy. [ 73 ] Lipid modification greatly increased the biocompatibility and stability of PLNPs in biological media. After being injected into mice, DCs labeled with lipid‐coated PLNPs can be imaged for several days and the migration process from injection sites to lymph nodes was also monitored successfully (Figure 9B).…”

Dual-Emissive Persistent Luminescence Nanoparticle-Based Charge-Reversible Intelligent Nanoprobe for Persistent Luminescence-Ratio Bioimaging along with Chemo-Photothermal Synergic Therapy

“…The pH of the mixture was adjusted to 8.0 with ammonia solution. The reaction solution was ultrasonicated at room temperature for 30 min and was stirred for a further 1.5 h. The turbid solution was transferred into a 50 mL Teflon-lined stainless steel autoclave and then heated at 220 °C for a certain period of time (12,24,36, and 48 h, respectively) for the hydrothermal reaction and cooled to room temperature. The resulting solution was centrifuged at 10000 rpm for 10 min and washed sequentially with ultrapure water and ethanol and then lyophilized.…”

“…10,11 However, current PLNPs are limited to single-wavelength emission and are susceptible to a luminescence variation with time after stopping excitation, which has impeded the further development of PLNPs in bioimaging. 12,13 A dual-emissive probe can perform self-calibration reading and ratio imaging by detecting the fluorescence intensities at two different wavelengths, thereby effectively avoiding the interference of external factors. Dual-emissive PLNPs, therefore, are expected to achieve constant ratio imaging with a long detection window, promoting the biomedical applications of PLNPs.…”