Advanced Optical Materials,
Год журнала:
2024,
Номер
12(19)
Опубликована: Май 11, 2024
Abstract
DNA‐stabilized
silver
nanoclusters
(DNA‐AgNCs)
are
a
class
of
emitters
that
have
primarily
been
studied
for
their
molecular‐like
photophysical
properties
with
ns‐lived
fluorescence.
However,
µs‐lived
luminescence
has
recently
reported
an
increasing
number
DNA‐AgNCs,
but
little
is
still
known
about
the
origin
long‐lived
emission.
To
deepen
understanding
state,
(DNA)
2
‐[Ag
11
]
7+
,
emitter
short‐
and
dual
emission,
studied.
By
examining
crystals
it
found
fluorescence
transitions
orthogonal
to
each
other,
which
implies
components
long
axis
AgNC,
such
as
nucleobases,
contribute
significantly
polarization
character
luminescent
state.
The
effect
hydration
level
on
emission
dried
droplets
also
investigated,
water
drastically
reduces
from
state
causes
redshift
Finally,
unusual
excitation
intensity‐dependent
response
noticed.
This
ascribed
heterogeneous
local
environment
amorphous
solid
resulting
in
different
conformations
optically
activated
delayed
probabilities.
presented
results
provide
new
key
insights
into
nature
DNA‐AgNCs.
Chemistry of Materials,
Год журнала:
2024,
Номер
36(19), С. 9003 - 9012
Опубликована: Май 28, 2024
Atomically
precise
metal
nanoclusters
are
of
high
interest
as
photocatalysts,
contrast
agents
for
biomedical
imaging,
unique
sensitizers
therapies,
and
more.
However,
these
fluorescent
materials
often
synthesized
mixtures,
especially
when
stabilized
by
peptides
other
water-soluble
ligands.
Fluorescence
spectroscopy,
acquired
a
matrix
excitation/emission
spectra
analyzed
with
principal
component
analysis,
such
parallel
factor
(PARAFAC)
can
be
highly
informative
in
assessing
purity
the
number
components
sample.
In
this
perspective,
advances
discussed,
well
use
fluorescence
excitation–emission
spectroscopy
(fEEM)
fast,
nondestructive
technique
sample
composition.
Hot
topics
cluster
research
including
new
classes
clusters,
theory-guided
experiments,
combination
analytical
techniques
ensuring
accurate
structure–property
studies
discussed.
Advanced Optical Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 16, 2025
Abstract
DNA‐stabilized
silver
nanoclusters
(DNA‐Ag
N
)
are
atomically
precise
and
sequence‐tuned
nanomaterials
with
potential
applications
for
deep
tissue
biomedical
imaging.
Here,
a
dual‐emissive
DNA‐Ag
is
presented
fluorescence
in
the
first
near‐infrared
(NIR‐I)
spectral
window
microsecond‐lived
photoluminescence
second
(NIR‐II)
window.
High‐resolution
electrospray
ionization
mass
spectrometry
showed
that
emitter
has
molecular
formula
(DNA)
2
[Ag
17
]
11+
.
The
crystallization
of
was
unsuccessful,
which
prevented
use
X‐ray
diffraction
to
determine
its
structure.
However,
sequence
variations
templating
DNA
oligomer
provided
insights
into
nucleobases
critical
stabilizing
Ag
Moreover,
addition
an
adenosine
or
thymidine
at
5′‐end
strand
maintained
composition
photophysical
properties
,
suggesting
site
conjugation
biomolecules
enable
targeted
labeling
future
bioimaging
applications.
DNA-stabilized
silver
nanoclusters
(DNA-AgNCs)
are
a
class
of
fluorophores
with
interesting
photophysical
properties.
They
capable
generating
anti-Stokes
fluorescence
upon
excitation
near-infrared
lasers.
The
has
previously
been
speculated
to
be
either
the
result
consecutive
photon
absorption
(upconversion)
or
hot
band
(HBA).
Here,
we
revisit
DNA-AgNCs
determine
underlying
mechanistic
origin.
We
investigate
two
studied
together
organic
and
emission
features
in
same
spectral
regions
as
DNA-AgNCs.
From
recorded
spectra,
find
that
all
emitters
exhibit
an
exponential-like
decaying
slope
on
red
side
lowest
energy
band.
Furthermore,
power
dependency
measurements
at
different
wavelengths
verify
one-photon
nature
fluorescence.
Ultimately,
lack
discrete
optical
transition
spectra
suggests
HBA
mechanism
is
most
plausible
cause
for
investigated
Small Structures,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 17, 2025
Fluorescence
imaging
is
a
key
tool
in
biological
and
medical
sciences.
Despite
the
potential
for
increased
depth
near‐infrared
range,
limited
availability
of
bright
emitters
hinders
its
widespread
implementation.
In
this
work,
DNA‐stabilized
silver
nanocluster
(DNA–AgNC)
with
emission
at
960
nm
solution
presented,
which
redshifts
further
to
1055
solid
crystalline
states.
The
atomic
structure,
composition
charge
DNA–AgNC
are
determined
by
combining
single‐crystal
X‐ray
diffraction
electrospray
ionization–mass
spectrometry.
This
unique
atomically
precise
consists
28
atoms,
neutral
(Ag
16+
),
arranged
rodlike
shape,
measures
just
over
2
length.
Interestingly,
differences
observed
number
chlorido
ligands
between
states,
highlighting
important
but
not
yet
fully
understood
role
chlorides
fine‐tuning
optical
properties
class
emitters.
structure
nanorod,
along
characterized
photophysical
properties,
represents
cornerstone
understanding
intricate
interactions
DNA
bases,
as
well
paving
way
rational
design
next‐generation
probes.
Near-infrared
(NIR)
emitters
with
high
two-photon
absorption
(2PA)
cross-sections
are
of
interest
to
enable
in
vivo
imaging
the
tissue
transparency
windows.
This
study
explores
potential
DNA-stabilized
silver
nanoclusters
(AgN-DNAs)
as
water-soluble
absorbers.
We
investigate
2PA
four
different
atomically
precise
AgN-DNA
species
far-red
NIR
emission
and
varying
nanocluster
ligand
compositions.
cross-sections,
σ2,
were
determined
by
excited
luminescence
(TPEL)
technique
for
a
wide
wavelength
range
from
810
1400
nm.
The
AgN-DNAs
exhibited
reversed
strength
corresponding
transitions
regime,
compared
one-photon,
which
adds
another
puzzle
complex
photophysics
these
emitters.
Maximal
cross-section
value
(813
GM)
was
observed
(DNA)3[Ag21]15+,
is
stabilized
3
DNA
oligomers.
(DNA)2[Ag16Cl2]8+
presented
distinct
behavior
without
chlorido
ligands,
presenting
176
GM
at
1050
Our
findings
support
NIR-to-NIR
probes
that
both
emit
NIR.
Their
σ2
fluorescence
quantum
yield
results
superior
brightness
on
order
~10^2
GM,
significantly
higher
than
organic
fluorophores.
Nanoscale,
Год журнала:
2024,
Номер
16(36), С. 16913 - 16918
Опубликована: Янв. 1, 2024
Here
we
demonstrate
the
synthesis
of
atomically
precise
Ag
16
NCs
and
their
photophysical
properties.
The
solvent-dependent
relaxation
dynamics
using
ultrafast
spectroscopy
has
been
investigated.
