No abstract

Fluorescent bioimaging in the second near-infrared window (NIR-II) can probe deep tissue with minimum auto-fluorescence and tissue scattering. However, current NIR-II fluorophore-related biodetection in vivo is only focused on direct disease lesion or organ bioimaging, it is still a challenge to realize NIR-II real-time dynamic biosensing. A new type of Er sensitized upconversion nanoparticles are presented with both excitation (1530 nm) and emission (1180 nm) located in the NIR-II window for in vivo biosensing. The microneedle patch sensor for in vivo inflammation dynamic detection is developed based on the ratiometric fluorescence by combining the effective NIR-II upconversion emission and H O sensing organic probes under the Fenton catalysis of Fe . Owing to the large anti-Stokes shifting, low auto-fluorescence, and tissue scattering of the NIR-II upconversion luminescence, inflammation can be dynamically evaluated in vivo at very high resolution (200×200 μm).

In vivo fluorescence imaging in the second near‐infrared window (NIR‐II) affords deep‐tissue penetration and high spatial resolution. Herein, we present a new type of Tm3+‐sensitized lanthanide nanocrystals with both excitation (1208 nm) and emission (1525 nm) located in the NIR‐II window for in vivo optical information storage and decoding. Taking advantage of the tunable fluorescence lifetimes, the optical multiplexed encoding capacity is enhanced accordingly. Micro‐devices with QR codes featuring the NIR‐II fluorescence‐lifetime multiplexed encoding were implanted into mice and were successfully decoded through time‐gated fluorescence imaging technology.

In the clinic, bone defects resulting from infections, trauma, surgical resection and genetic malformations remain a significant challenge. In the field of bone tissue engineering, three-dimensional (3D) scaffolds are promising for the treatment of bone defects. In this study, calcium sulfate hydrate (CSH)/mesoporous bioactive glass (MBG) scaffolds were successfully fabricated using a 3D printing technique, which had a regular and uniform square macroporous structure, high porosity and excellent apatite mineralization ability. Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured on scaffolds to evaluate hBMSC attachment, proliferation and osteogenesis-related gene expression. Critical-sized rat calvarial defects were applied to investigate the effect of CSH/MBG scaffolds on bone regeneration in vivo. The in vitro results showed that CSH/MBG scaffolds stimulated the adhesion, proliferation, alkaline phosphatase (ALP) activity and osteogenesis-related gene expression of hBMSCs. In vivo results showed that CSH/MBG scaffolds could significantly enhance new bone formation in calvarial defects compared to CSH scaffolds. Thus 3D printed CSH/MBG scaffolds would be promising candidates for promoting bone regeneration.

Fluorescence lifetime imaging provides more possibility of in vivo multiplexing in second near infrared (NIR‐II) window. However, it still faces the obstacle that fluorescent probes with differentiable lifetime often exhibit quite different fluorescence intensity, especially the short lifetime usually accompanies with a weak fluorescence intensity, resulting in the difficulty for simultaneously decoding multiplexed lifetime information due to the interference of background noise. To facilitate high‐fidelity lifetime multiplexed imaging, we developed a series of Er3+ doped double interface fluorescent nanoprobes (Er‐DINPs): α‐NaYF4@NaErF4: Ce@NaYbF4@NaErF4: Ce@NaYF4 with strong fluorescence intensity and easily distinguishable fluorescence lifetime. Both in vitro and in vivo experimental results confirmed the advantage of these probes with comparable fluorescence intensity for high‐fidelity multiplexed lifetime bioimaging.

In situ monitoring of tissue regeneration progression is of primary importance to basic medical research and clinical transformation. Despite significant progress in the field of tissue engineering and regenerative medicine, few technologies have been established to in situ inspect the regenerative process. Here, we present an integrated second near-infrared (NIR-II, 1000–1700 nm) window in vivo imaging strategy based on 3D-printed bioactive glass scaffolds doped with NIR-II ratiometric lanthanide-dye hybrid nanoprobes, allowing for in situ monitoring of the early inflammation, angiogenesis, and implant degradation during mouse skull repair. The functional bioactive glass scaffolds contribute to more effective bone regeneration because of their excellent angiogenic and osteogenic activities. The reliability of ratiometric fluorescence imaging, coupled with low autofluoresence in the NIR-II window, facilitates the accuracy of in vivo inflammation detection and high-resolution visualization of neovascularization and implant degradation in deep tissue.

Kidney disease is usually “silent” at the early stage but can lead to severe kidney failure later on. The development of bioimaging probes with rapid distribution and long‐term retention in the kidney is significant for the precise diagnosis of renal diseases. Here, a strategy for the peptide‐mediated delivery and long‐term accumulation (>48 h) of second near‐infrared window (NIR‐II) fluorophores into the kidney is demonstrated. It is shown that both the hepatic‐cleared organic molecules and fast renal‐cleared ultrasmall nanoparticles can be retained in the kidney after conjugation to the peptide with high polarity. Moreover, a ROS‐responsive activatable bilateral NIR‐II sensor was designed based on the kidney targeting peptide, which enables both in vivo long‐term kidney monitoring and in vitro urine analysis. The capability of the peptide‐based sensor to detect early kidney injury and report on kidney dysfunctional progression is particularly crucial for chemotherapy regimen optimization and timely renoprotective intervention during medication.

Fluorescent bioimaging in the second near-infrared window (NIR-II) can probe deep tissue with minimum autofluorescence and tissue scattering. However,c urrent NIR-II fluorophore-related biodetection in vivo is only focused on direct disease lesion or organ bioimaging,itisstill ac hallenge to realizeNIR-II real-time dynamic biosensing. Anew type of Er 3+ sensitized upconversion nanoparticles are presented with both excitation (1530 nm) and emission (1180 nm) located in the NIR-II windowf or in vivo biosensing.T he microneedle patch sensor for in vivo inflammation dynamic detection is developed based on the ratiometric fluorescence by combining the effective NIR-II upconversion emission and H 2 O 2 sensing organic probes under the Fenton catalysis of Fe 2+ .Owing to the large anti-Stokes shifting, lowa uto-fluorescence,a nd tissue scattering of the NIR-II upconversion luminescence,i nflammation can be dynamically evaluated in vivo at very high resolution (200 200 mm).