2 research outputs found
Smart Magnetic Nanosensors Synthesized through Layer-by-Layer Deposition of Molecular Beacons for Noninvasive and Longitudinal Monitoring of Cellular mRNA
Noninvasive and longitudinal monitoring
of gene expression in living cells is essential for understanding
and monitoring cellular activities. Herein, a smart magnetic nanosensor
is constructed for the real-time, noninvasive, and longitudinal monitoring
of cellular mRNA expression through the layer-by-layer deposition
of molecular beacons (MBs) and polyethylenimine on the iron oxide
nanoparticles. The loading of MBs, responsible for the signal intensity
and the tracking time, was easily tuned with the number of layers
incorporated. The idea was first demonstrated with the magnetic nanosensors
for glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA, which was
efficiently internalized into the cells under the influence of magnetic
field. This nanosensor allowed the continuous monitoring of the cellular
GAPDH mRNA expression for 1 month. Then this platform was further
utilized to incorporate two kinds of MBs for alkaline phosphatase
(ALP) and GAPDH mRNAs, respectively. The multifunctional nanosensors
permitted the simultaneous monitoring of the reference gene (GAPDH
mRNA) and the early osteogenic differentiation marker (ALP mRNA) expression.
When the fluorescence signal ratio between ALP mRNA MBs and GAPDH
mRNA MBs was taken, the dynamic osteogenic differentiation process
of MSCs was accurately monitored
Fluorescent Poly(glycerol-<i>co</i>-sebacate) Acrylate Nanoparticles for Stem Cell Labeling and Longitudinal Tracking
The
stable presence of fluorophores within the biocompatible and
biodegradable elastomer polyÂ(glycerol-<i>co</i>-sebacate)
acrylate (PGSA) is critical for monitoring the transplantation, performance,
and degradation of the polymers <i>in vivo</i>. However,
current methods such as physically entrapping the fluorophores in
the polymer matrix or providing a fluorescent coating suffer from
rapid leakage of fluorophores. Covalent conjugation of fluorophores
with the polymers and the subsequent core-cross-linking are proposed
here to address this challenge. Taking rhodamine as the model dye
and PGSA nanoparticles (NPs) as the model platform, we successfully
showed that the synthesized rhodamine-conjugated PGSA (PGSAR) NPs
only released less than 30% rhodamine at day 28, whereas complete
release of dye occurred for rhodamine-encapsulated PGSA (PGSA-p-R)
NPs at day 7 and 57.49% rhodamine was released out for the un-cross-linked
PGSAR NPs at day 28. More excitingly, PGSAR NPs showed a strong quantum
yield enhancement (26.24-fold) of the fluorophores, which was due
to the hydrophobic environment within PGSAR NPs and the restricted
rotation of (6-diethylamino-3<i>H</i>-xanthen-3-ylidene)
diethyl group in rhodamine after the conjugation and core-cross-linking.
The stable presence of dye in the NPs and enhanced fluorescence allowed
a longitudinal tracking of stem cells both <i>in vitro</i> and <i>in vivo</i> for at least 28 days