As
key characteristic molecules, several H2S-activated
probes have been explored for colon cancer studies. However, a few
ratiometric fluorescence (FL) probes with NIR-II emissions have been
reported for the quantitative detection of H2S in colon
cancer in vivo. Here, we developed an in
situ H2S-activatable ratiometric nanoprobe with
two NIR-II emission signals for the detection of H2S and
intelligently lighting up colon cancer. The nanoprobe comprised a
down conversion nanoparticle (DCNP), which emitted NIR-II FL at 1550
nm on irradiation with a 980 nm laser (F1550Em, 980Ex). Further, human serum albumin (HSA) was combined with Ag+ on the surface of DCNP to form a DCNP@HSA-Ag+ nanoprobe.
In the presence of H2S, Ag2S quantum dots (QDs)
were formed in coated HSA, which emitted FL at approximately 1050
nm on irradiation with an 808 nm laser (F1050Em, 808Ex) through an H2S-induced chemical reaction between H2S and Ag+; however, the FL signal of DCNP was stable
at 1550 nm (F1550Em, 980Ex), generating a H2S concentration-dependent ratiometric F1050Em, 808Ex/F1550Em, 980Ex signal. The NIR-II ratiometric nanoprobe
was successfully used for the accurate quantitative detection of H2S and the detection of the precise location of colon cancer
through an endogenous H2S-induced in situ reduction reaction to form Ag2S QDs. Thus, these findings
provide a new strategy for the specific detection of targeted molecules
and diagnosis of disease based on the in situ-activatable
NIR-II ratiometric FL nanoprobe.
Janus nanogap gold nanoparticles (JAuNNPs) with varying proportions of Au shell coverage of (ca. 100/75/50/25 %) are presented. The internal nanogap between the partial Au shell and core caused asymmetric optical behavior; tunability depends on the degree of Au shell coverage and structural asymmetry. The shell‐to‐shell or core‐to‐core JAuNNDs(50 %) were self‐assembled from amphiphilic JAuNNPs(50 %) by tuning the hydrophilic and hydrophobic polymer brushes on the Au core or shell. The positions of electromagnetic field enhancement of JAuNNDs varied with geometrical configurations because of hybridized plasmonic coupling effects. Furthermore, DNA linkers were utilized to form JAuNND12(50 %). By combining with Raman molecules, ratiometric SERS signals could be generated, enabling JAuNND12(50 %) to image the distribution of miR‐21 in living cells and tumors. Asymmetric JAuNNPs allowed facile conjugation of various linkage molecules to fabricate dimeric nanostructures.
Wilson's disease (WD) is a rare inherited disorder of copper metabolism with pathological copper hyperaccumulation in some vital organs. However, the clinical diagnosis technique of WD is complicated, aggressive, and time‐consuming. In this work, a novel ratiometric photoacoustic (PA) imaging nanoprobe in the NIR‐II window is developed to achieve noninvasive, rapid, and accurate Cu2+ quantitative detection in vitro and in vivo. The nanoprobe consists of Cu2+‐responsive IR970 dye and a nonresponsive palladium‐coated gold nanorod (AuNR‐Pd), achieving a concentration‐dependent ratiometric PA970/PA1260 signal change. The urinary Cu2+ content is detectable within minutes down to a detection limit of 76 × 10−9 m. This report acquisition time is several orders of magnitude shorter than those of existing detection approaches requiring complex procedure. Moreover, utilizing the ratiometric PA nanoprobe, PA imaging enables biopsy‐free measurement of the liver Cu2+ content and visualization of the liver Cu2+ biodistribution of WD patient, which avoid the body injury during the clinical Cu2+ test using liver biopsy method. The NIR‐II ratiometric PA detection method is simple and noninvasive with super precision, celerity, and simplification, which holds great promise as an alternative to liver biopsy for clinical diagnosis of WD.
Delays in evaluating cancer response to radiotherapy (RT) usually reduce therapy effect or miss the right time for treatment optimization. Hence, exploring timely and accurate methods enabling one to gain insights of RT response are highly desirable. In this study, we have developed an apoptosis enzyme (caspase-3) activated nanoprobe for early evaluation of RT efficacy. The nanoprobe bridged the nanogapped gold nanoparticles (AuNNPs) and the second near-infrared window (NIR-II) fluorescent (FL) molecules (IR-1048) through a caspase-3 specific peptide sequence (DEVD) (AuNNP@DEVD-IR1048). After X-ray irradiation, caspase-3 was activated to cut DEVD, turning on both NIR-II FL and PA imaging signals. The increased NIR-II FL/PA signals exhibited a positive correlation with the content of caspase-3. Moreover, the amount of the activated caspase-3 was negatively correlated with the tumor size. The results underscore the role of the caspase-3 activated by X-ray irradiation in bridging the imaging signals variation and tumor inhibition rate. Overall, activatable NIR-II FL/PA imaging was successfully used to timely predict and evaluate the RT efficacy. The evaluation system based on biomarkertriggered living imaging has the capacity to guide treatment decisions for numerous cancer types.
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