Synthesis procedures of nanocrystals and NO recognition molecules, preparation of test paper, mass spectra, TEM images of the UCNPs, luminescence variations of the nanoprobes upon additions of different interference anion ions, and luminescent images of the test paper after exposure to different amounts of NO (PDF)
Sensitive
detection of alkaline phosphatase (ALP) activity in human
serum is important for diagnosis of various diseases. In this work,
a novel sandwich-structured upconversion nanoparticle, NaYF4:Yb/Er@NaErF4@NaYF4, is fabricated to construct
an upconversional nanoprobe for ultrasensitive detection of phosphate
and ALP activity. The inner shell of NaErF4 bridges the
emitters in the core with the external luminescence quenchers to greatly
improve the energy transfer efficiency. The quencher, herein, is a
coordination complex formed between sulfosalicylic acid and ferric
ions. Owing to the higher affinity for phosphate, ferric ions dissociate
from the complex and potently combine with phosphate ions, thus interrupting
the energy transfer process and recovering the luminescence. This
upconversional nanoprobe shows rapid and sensitive detection of phosphate
with a limit of detection of 2.5 nM. Because ALP catalyzes the hydrolysis
of p-nitrophenyl phosphate to form p-nitrophenol and inorganic phosphate ions, the nanoprobe is further
utilized to achieve sensitive detection of ALP with a limit of detection
of 0.5 μU/mL. This novel strategy offers a new opportunity for
developing sensitive upconversional nanoprobes and many other energy
transfer-based applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.