Alzheimer’s
disease (AD) is a neurodegenerative disease,
and β-amyloid (Aβ) is believed to be a causative factor
in AD pathology. The abnormal deposition of Aβ is believed to
be responsible for progression of AD. In order to facilitate the imaging
of Aβ
in vivo
, suitable probe molecules with
a near-infrared emission wavelength that can penetrate the blood–brain
barrier (BBB) were utilized. The commercial fluorescent probe thioflavin-T
(ThT) is used to image Aβ; however, because of its short emission
wavelength and poor BBB penetration, ThT can only be used
in vitro
. With this research, based on ThT, we design three
fluorescent probes (SZIs) having a longer emission wavelength in order
to image Aβ aggregates. SZIs with different numbers of double
bonds respond to Aβ aggregates. The SZIs have a structure similar
to ThT, and as such, the SZIs are also unable to penetrate the BBB.
To deal with the problem, we develop nanocomposites (MSN-Lf@SZIs)
to deliver SZIs into the brain of AD mouse and image Aβ successfully.
These new nanocomposites are able to deliver the dyes into the brain
and facilitate Aβ imaging
in vivo
.