Orthogonal Near-Infrared-II Imaging Enables Spatially Distinguishing Tissues Based on Lanthanide-Doped Nanoprobes

Abstract

Multichannel near-infrared (NIR)-II imaging provides more precise and detailed information for studying complex biological processes. When studying specific biological processes, a separated single signal and multisignals are essential but difficult to obtain by traditional multichannel NIR-II imaging methods. Taking advantage of the unique optical properties of lanthanide ions, especially in atom-like absorbance and emission spectroscopy in the NIR region, in this study, we synthesized two lanthanide-doped nanoprobes, NaYF4:Gd@NaYF4:Nd@NaYF4 (cssNd) and NaYF4:Gd@NaYF4:Er@NaYF4 (cssEr). These two nanoprobes show orthogonal NIR-II emissions (1064 and 1330 nm for cssNd and 1550 nm for cssEr) under 730 and 980 nm excitation, respectively. The feasibility of cssNd and cssEr for multichannel NIR-II imaging was proven in vitro. Under different methods of administering the nanoprobes, in vivo multichannel NIR-II imaging with both the separated single signal and multisignals was successfully performed and could spatially distinguish tissues under two different excitation sources. Our results provide a new method for multichannel NIR-II imaging with separable signals, which is promising for precisely studying complex biological processes precisely.

Biomedical Applications of Lanthanide Nanomaterials, for Imaging, Sensing and Therapy

“…With this feature, the same wavelength excitation source could be used to achieve different emission wavelengths for multichannel or multiplexed imaging (Fig. 4B, E) [67,68].…”

Activatable NIR‐II Fluorescent Probes Applied in Biomedicine: Progress and Perspectives

“…With the continuous emergence of excellent NIR‐II AFPs, the application of NIR‐II biological imaging technology in biomedical field has made considerable progress. Here, certain significant researches that associated with NIR‐II bioimaging of NIR‐II AFPs are presented, including precise tissue bioimaging, [90–94] dynamic bioimaging for monitoring [95–98] and multiplexed bioimaging [99–102] …”

“…TSSAM showed clearer and more accurate imaging of tumor tissue through the three‐mode imaging of photoacoustic/NIR‐II fluorescence/photothermal imaging, and was considered a typical example of multiplexed imaging that maximizes the energy of excited states. Additionally, Zhou's group reported the multiplexed NIR‐II bioimaging with single signal and multiple signals had been achieved by using NaYF 4 : Gd@NaYF 4 : Nd@NaYF 4 and NaYF 4 : Gd@NaYF 4 : Er@NaYF 4 fluorophores [102] …”

Near-Infrared Frequency Upconversion Luminescence Bioimaging Based on Cyanine Nanomicelles

“…12 At present, the use of the near-infrared (NIR) light excitation and emission strategy and the upconversion luminescence strategy could solve the above problems. 13,14 For in vivo imaging using NIR light, cyanine dyes are widely regarded as a class of effective NIR fluorophores because of high molar/mass extinction coefficients and fluorescence quantum yields. 15−18 Because it has the advantages of strong tissue penetration, little damage to biological samples, and low background interference, it is widely used in in vivo diagnosis and optical imaging.…”

“…For instance, visible light excitation and emission will cause serious self-luminescence interference, low light penetration depth, and poor signal-to-noise ratio . At present, the use of the near-infrared (NIR) light excitation and emission strategy and the upconversion luminescence strategy could solve the above problems. , …”