We report the use of phenolic functional
groups of lignosulfonate
to impart antioxidant properties and the cell binding domains of gelatin
to enhance cell adhesion for poly(ethylene glycol) (PEG)-based scaffolds.
Chemoselective thiol–ene chemistry was utilized to form composites
with thiolated lignosulfonate (TLS) and methacrylated fish gelatin
(fGelMA). Antioxidant properties of TLS were not altered after thiolation
and the levels of antioxidation were comparable to those of
L
-ascorbic acid. PEG-fGelMA-TLS composites significantly
reduced the difference in
COL1A1
,
ACTA2
,
TGFB1
, and
HIF1A
genes between
high-scarring and low-scarring hdFBs, providing the potential utility
of TLS to attenuate fibrotic responses.
Three-dimensional
matrices of collagen type I (Col I) are widely
used in tissue engineering applications for its abundance in many
tissues, bioactivity with many cell types, and excellent biocompatibility.
Inspired by the structural role of lignin in a plant tissue, we found
that sodium lignosulfonate (SLS) and an alkali-extracted lignin from
switchgrass (SG) increased the stiffness of Col I gels. SLS and SG
enhanced the stiffness of Col I gels from 52 to 670 Pa and 52 to 320
Pa, respectively, and attenuated shear-thinning properties, with the
formulation of 1.8 mg/mL Col I and 5.0 mg/mL SLS or SG. In 2D cultures,
the cytotoxicity of collagen–SLS to adipose-derived stromal
cells was not observed and the cell viability was maintained over
7 days in 3D cultures. Collagen–SLS composites did not elicit
immunogenicity when compared to SLS-only groups. Our collagen–SLS
composites present a case that exploits lignins as an enhancer of
mechanical properties of Col I without adverse cytotoxicity and immunogenicity
for in vitro scaffolds or in vivo tissue repairs.
Imaging and quantification of stained blood cells are important for identifying the cells in hematology and for diagnosing diseased cells or parasites in cytopathology. Romanowsky staining have been used traditionally to produce hues in blood cells using anionic eosin Y and cationic methylene blue. While Romanowsky stains have been widely used in cytopathology, end-users have experienced problems with varying results in staining due to premature precipitation or evaporation of methanol, leading to the inherent inconsistency of solution-based Romanowsky staining. Here, we demonstrate that staining and destaining of blood smear are controllable by the contact time of agarose gel stamps. While the extent of staining and destaining are discernable by hue values of stamped red blood cells in micrographs, quantification of adsorbed and desorbed Romanowsky dye molecules (in particular, eosin Y, methylene blue, and azure B) from and to the agarose gel stamps needs a model that can explain the sorption process. We find predictable sorption of the Romanowsky dye molecules from the pseudo-second-order kinetics models for adsorption and the one phase decay model for desorption. Thus, the method of agarose gel stamping demonstrated here could be an alternative to solution-based Romanowsky staining with predictable quantity of sorption and timing of contact.
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