posted on 2019-01-03, 00:00authored byYoubin Li, Songjun Zeng, Jianhua Hao
Visualization of
tumor vessels/metastasis and cerebrovascular architecture
is vitally important for analyzing pathological states of brain diseases
and a tumor’s abnormal blood vessels to improve cancer diagnoses. In vivo fluorescence imaging using second near-infrared
emission beyond 1500 nm (NIR-IIb) has emerged as a next generation
optical imaging method with significant improvement in imaging sensitivity
and spatial resolution. Unfortunately, a highly biocompatible probe
capable of generating NIR-IIb emission with sufficient brightness
and uniformed size is still scarce. Here, we have proposed the poly(acrylic
acid) (PAA)-modified NaLnF4:40Gd/20Yb/2Er nanorods (Ln
= Y, Yb, Lu, PAA-Ln-NRs) with enhanced downshifting NIR-IIb emission,
high quantum yield (QY), relatively narrow bandwidth (∼160
nm), and high biocompatibility via Ce3+ doping for high
performance NIR-IIb bioimaging. The downshifting emission beyond 1500
nm is improved by 1.75–2.2 times with simultaneously suppressing
the upconversion (UC) path in Y, Yb, and Lu hosts via Ce3+ doping. Moreover, compared with the traditionally used Y-based host,
the QY of NIR-IIb emission in the Lu-based probe in water is improved
from 2.2% to 3.6%. The explored bright NIR-IIb emitted PAA-Lu-NRs
were used for high sensitivity small tumor (∼4 mm)/metastatic
tiny tumor detection (∼3 mm), tumor vessel visualization with
high spatial resolution (41 μm), and brain vessel imaging. Therefore,
our findings open up the opportunity of utilizing the lanthanide based
NIR-IIb probe with bright 1525 nm emission for in vivo optical-guided tumor vessel/metastasis and noninvasive brain vascular
imaging.