Optical bioimaging is an indispensable tool in modern biology and medicine, but the technique is susceptible to autofluorescence interference. Persistent nanophosphors provide an easy-to-perform and highly efficient means to eliminate tissue autofluorescence. However, direct synthesis of persistent nanophosphors with tunable properties to meet different bioimaging requirements remains largely unexplored. In this work, zinc gallogermanate (ZnGaGeO:Cr, 0 ≤ x ≤ 0.5, ZGGO:Cr) persistent luminescence nanoparticles with composition-dependent size and persistent luminescence are reported. The size of the ZGGO:Cr nanoparticles gradually increases with the increase of x in the chemical formula. Moreover, the intensity and decay time of persistent luminescence in ZGGO:Cr nanoparticles can also be fine-tuned by simply changing x in the formula. In vivo bioimaging tests demonstrate that ZGGO:Cr nanoparticles can efficiently eliminate tissue autofluorescence, and the nanoparticles also show good promise in long-term bioimaging as they can be easily reactivated in vivo. Furthermore, an aptamer-guided ZGGO:Cr bioprobe is constructed, and it displays excellent tumor-specific accumulation. The ZGGO:Cr nanoparticles are ideal for autofluorescence-free targeted bioimaging, indicating their great potential in monitoring cellular networks and construction of guiding systems for surgery.
Persistent luminescence nanoparticles (PLNPs) are an emerging group of promising luminescent materials that can remain luminescent after the excitation ceases. In the past decade, PLNPs with intriguing optical properties have been developed and their applications in biomedicine have been widely studied. Due to the ultra-long decay time of persistent luminescence, autofluorescence interference in biosensing and bioimaging can be efficiently eliminated. Moreover, PLNPs can remain luminescent for hours, making them valuable in bio-tracing. Also, persistent luminescence imaging can guide cancer therapy with a high signal-to-noise ratio (SNR) and superior sensitivity. Briefly, PLNPs are demonstrated to be a newly-emerging class of functional materials with unprecedented advantages in biomedicine. In this review, we summarized recent advances in the preparation of PLNPs and the applications of PLNPs in biosensing, bioimaging and cancer therapy.
Persistent luminescence nanoparticles (PLNPs), which can remain luminescent after cessation of excitation, have emerged as important materials in biomedicine due to their special ability to eliminate tissue autofluorescence. Even though significant advances have been made in bioimaging, studies on controlled synthesis of PLNPs with tunable properties are lacking. Until now, only a few studies have reported the synthesis of quasi-spherical ZnGaO:Cr PLNPs, and direct synthesis of PLNPs with other shapes and chemical compositions has not been reported. Herein, we report the direct synthesis of ZnGeO:Mn (ZGO:Mn) persistent luminescence nanorods (NRs). The length and persistent luminescence of ZGO:Mn NRs can be fine-tuned by simply changing the pH of the hydrothermal reaction system. Moreover, ZGO:Mn NRs exhibit rapid growth rate, and NRs with strong persistent luminescence can be obtained within 30 min of hydrothermal treatment. Aptamer-guided ZGO:Mn bioprobes were further constructed and applied to serum lysozyme analysis. Serum samples from patients with lung cancer, gastric cancer, and colorectal cancer were collected, and the concentrations of lysozyme in these samples were determined. Since the bioprobes displayed long persistent luminescence, serum autofluorescence interference was completely eliminated. The lysozyme quantification results were in good agreement with those obtained using a clinical method, suggesting the good potential of the bioprobes in the analysis of clinical samples. The developed ZGO:Mn NRs possess tunable length and persistent luminescence, and they are ideal for eliminating autofluorescence interference in biosensing, making them valuable in research areas such as studying the functions of biomolecules and monitoring of molecular/cellular networks in their native contexts.
Physical cues of the scaffolds, elasticity, and stiffness significantly guide adhesion, proliferation, and differentiation of stem cells. In addressable microenvironments constructed by three-dimensional graphene foams (3D-GFs), neural stem cells (NSCs) interact with and respond to the structural geometry and mechanical properties of porous scaffolds. Our studies aim to investigate NSC behavior on the various stiffness of 3D-GFs. Two kinds of 3D-GFs scaffolds present soft and stiff properties with elasticity moduli of 30 and 64 kPa, respectively. Stiff scaffold enhanced NSC attachment and proliferation with vinculin and integrin gene expression were up-regulated by 2.3 and 1.5 folds, respectively, compared with the soft one. Meanwhile, up-regulated Ki67 expression and almost no variation of nestin expression in a group of the stiff scaffold were observed, implying that the stiff substrate fosters NSC growth and keeps the cells in an active stem state. Furthermore, NSCs grown on stiff scaffold exhibited enhanced differentiation to astrocytes. Interestingly, differentiated neurons on stiff scaffold are suppressed since growth associated protein-43 expression was significantly improved by 5.5 folds.
Structure–performance relationships: the structural properties of mesoporous materials that can be optimized to improve the analytical performance are discussed.
Luminescent nanomaterials have attracted great attention in luminescence‐based bioanalysis due to their abundant optical and tunable surface physicochemical properties. However, luminescent nanomaterials often suffer from serious autofluorescence and light scattering interference when applied to complex biological samples. Time‐resolved luminescence methodology can efficiently eliminate autofluorescence and light scattering interference by collecting the luminescence signal of a long‐lived probe after the background signals decays completely. Lanthanides have a unique [Xe]4fN electronic configuration and ladder‐like energy states, which endow lanthanide‐doped nanoparticles with many desirable optical properties, such as long luminescence lifetimes, large Stokes/anti‐Stokes shifts, and sharp emission bands. Due to their long luminescence lifetimes, lanthanide‐doped nanoparticles are widely used for high‐sensitive biosensing and high‐contrast bioimaging via time‐resolved luminescence methodology. In this review, recent progress in the development of lanthanide‐doped nanoparticles and their application in time‐resolved biosensing and bioimaging are summarized. At the end of this review, the current challenges and perspectives of lanthanide‐doped nanoparticles for time‐resolved bioapplications are discussed.
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