2 research outputs found
Flavonoids, Flavonoid Metabolites, and Phenolic Acids Inhibit Oxidative Stress in the Neuronal Cell Line HT-22 Monitored by ECIS and MTT Assay: A Comparative Study
A real-time and label-free in vitro
assay based on electric cell-substrate
impedance sensing (ECIS) was established, validated, and compared
to an end-point MTT assay within an experimental trial addressing
the cytoprotective effects of 19 different flavonoids, flavonoid metabolites,
and phenolic acids and their methyl esters on the HT-22 neuronal cell
line, after induction of oxidative stress with <i>tert</i>-butyl hydroperoxide. Among the flavonoids under study, only those
with a catechol unit and an additional 4-keto group provided cytoprotection.
The presence of a 2,3-double bond was not a structural prerequisite
for a neuroprotective effect. In the case of the phenolics, catechol
substitution was the only structural requirement for activity. The
flavonoids and other phenolics with a ferulic acid substitution or
a single hydroxy group showed no activity. Electrochemical characterization
of all compounds via square-wave voltammetry provided a rather specific
correlation between cytoprotective activity and redox potential for
the active flavonoids, but not for the active phenolics with a low
molecular weight. Moreover this study was used to compare label-free
ECIS recordings with results of the established MTT assay. Whereas
the former provides time-resolved and thus entirely unbiased information
on changes of cell morphology that are unequivocally associated with
cell death, the latter requires predefined exposure times and a strict
causality between metabolic activity and cell death. However, MTT
assays are based on standard lab equipment and provide a more economic
way to higher throughput
Tracking Hyaluronan: Molecularly Imprinted Polymer Coated Carbon Dots for Cancer Cell Targeting and Imaging
War
against cancer constantly requires new affinity tools to selectively
detect, localize, and quantify biomarkers for diagnosis or prognosis.
Herein, carbon nanodots (CDs), an emerging class of fluorescent nanomaterials,
coupled with molecularly imprinted polymers (MIPs), are employed as
a biocompatible optical imaging tool for probing cancer biomarkers.
First, N-doped CDs were prepared by hydrothermal synthesis using starch
as carbon source and l-tryptophan as nitrogen atom provider
to achieve a high quantum yield of 25.1 ± 2%. The CDs have a
typical size of ∼3.2 nm and produce an intense fluorescence
at 450 nm upon excitation with UV light. A MIP shell for specific
recognition of glucuronic acid (GlcA) was then synthesized around
the CDs, using the emission of the CDs as an internal light source
for photopolymerization. GlcA is a substructure (epitope) of hyaluronan,
a biomarker for certain cancers. The biotargeting and bioimaging of
hyaluronan on fixated human cervical cancer cells using CD core-MIP
shell nanocomposites is demonstrated. Human keratinocytes were used
as noncancerous reference cells and indeed, less staining was observed
by the CD-MIP