Crucial Breakthrough of Functional Persistent Luminescence Materials for Biomedical and Information Technological Applications

Abstract

Persistent luminescence is a phenomenon in which luminescence is maintained for minutes to hours without an excitation source. Owing to their unique optical properties, various kinds of persistent luminescence materials (PLMs) have been developed and widely employed in numerous areas, such as bioimaging, phototherapy, data-storage, and security technologies. Due to the complete separation of two processes, -excitation and emission-, minimal tissue absorption, and negligible autofluorescence can be obtained during biomedical fluorescence imaging using PLMs. Rechargeable PLMs with super long afterglow life provide novel approaches for long-term phototherapy. Moreover, owing to the exclusion of external excitation and the optical rechargeable features, multicolor PLMs, which have higher decoding signal-to-noise ratios and high storage capability, exhibited an enormous application potential in information technology. Therefore, PLMs have significantly promoted the application of optics in the fields of multimodal bioimaging, theranostics, and information technology. In this review, we focus on the recently developed PLMs, including inorganic, organic and inorganic-organic hybrid PLMs to demonstrate their superior applications potential in biomedicine and information technology.

Keywords: anti-counterfeiting; bioimaging; biomedical applications; biosensing; information technological applications; optical data recording; persistent luminescence material; therapy.

Figure 1

(A) PL decay curve monitored at 370 nm after irradiation by 254-nm UV for 15 min (Liang et al., 2015). (B) NIR images of four Zn₃Ga₂Ge₂O10: 0.5%Cr³⁺ phosphor discs taken at different afterglow times after irradiation by a 365-nm lamp for durations ranging from 10 s to 5 min (Pan et al., 2012). (C) Energy transfer mechanism of UCPL materials (left), and the PL spectra of green emission UCPL materials taken 30 s after the excitation under 980-nm and UV lights for 15 s (right) (Hu et al., 2017). Reproduced with permission from Dalton Transactions, Nature Materials and Advanced Optical Materials.

Figure 2

(A) Rational design of molecular rotors (top) and ultra-long organic phosphorescence deactivation process by monitoring the emission intensities at 530 nm under ambient conditions (bottom) (Gu et al., 2018). (B) Energy transfer processes for transient and persistent ML of ImBr (top) and tricolor emission switching of ImB (bottom) (Li et al., 2018). (C) Emission mechanism of organic PL (Kabe and Adachi, 2017). (D) Schematic of the FRET from the MEH-PPV polymer to the NIR775 dye (left), and fluorescence spectra of the NPs with and without NIR775 dye, and absorbance spectrum of the NPs with NIR775 (right) (Mikael et al., 2015). Reproduced with permission from Angewandte Chemie International Edition, Nature, and Angewandte Chemie, respectively.

Figure 3

(A) First PLNP-based in vivo bioimaging (le Masne de Chermont et al., 2007). (i) Schematic of the experimental procedure of the in vivo imaging. (ii) Living image of NPs via subcutaneous injection. (iii) Living image of NPs via intramuscular injection. (B) NIR-to-NIR upconverted persistent probe for in vivo bioimaging (Zeng et al., 2017). (i) Schematic of the preparation and experimental procedure of UC-PLNPs for in vivo bioimaging. (ii) In vivo images of UC-PLNPs under 980-nm excitation. (iii) Biodistribution of UP-PLNPs in major organs. Reproduced with permission from copyright (2007) National Academy of Sciences and Nanoscale, respectively.

Figure 4

(A) Photothermal therapy using ICG-PLPs@mSiO₂ (Zheng et al., 2016). (B) Photodynamic therapy using NIR light rechargeable UC-PLNPs (Hu et al., 2018). Reproduced with permission from ACS Applied Materials and Interfaces and Biomaterials, respectively.

Figure 5

(A) PLNP-based detection of AFP (Wu et al., 2011). (i) Schematic of the AFP detection of PEI-PLNPs and Ab-AuNPs. (ii) Fluorescent images of three cell lines with PLNP-based probes. (B) PLNR-based detection of serum lysozyme (Wang et al., 2017b). (i) Schematic of lysozyme biosensing. (ii) Detected concentrations of lysozyme by PLNRs and ELISA. Reproduced with permission from Journal of the American Chemical Society and ACS Nano, respectively.

Figure 6

(A) Pattern designed with different phosphors and demonstration of multilevel anti-counterfeiting using MCzT, PCzT, BCzT, and FCzT crystals (Gu et al., 2018). (B) Photographs of handwritten characters on a cigarette case under a UV lamp (254 nm) and after the lamp is switched off (Gao et al., 2017). (C) Typical objects stamped with orthogonal multicolor UCPL materials and the luminescence images when the 980-nm excitation is switched on and off (Hu et al., 2017). Reproduced with permission from Angewandte Chemie International Edition, Nano Research and Advanced Optical Materials, respectively.

Figure 7

NIR-writing encryption process and heat-induced decryption process (Hu et al., 2017). Reproduced with permission from Advanced Optical Materials.