3 research outputs found
Tannic Acid as a Degradable Mucoadhesive Compound
To
achieve site-specific delivery of pharmaceuticals, the development
of effective mucoadhesive polymers is essential. Thus far, only a
few polymers, such as thiolated ones and related variants, have been
studied. However, their mucoadhesiveness varies depending on the type
of polymer and the degree of chemical functionalization. Furthermore,
the chemistry of tethering often requires harsh reaction conditions.
Recently, pyrogallol-containing molecules have emerged as good tissue
and hemostatic adhesives, but their in vivo mucoadhesive properties
have not been demonstrated. Herein, we found that pyrogallol-rich
tannic acid (TA) formulated with polyÂ(ethylene glycol) (PEG), named
TAPE, exhibits superior mucoadhesive properties. TAPE is prepared
by a simple physical mixture of TA and PEG. It remained on esophageal
mucus layers for at least several hours (<8 h) after oral feeding.
The mucoadhesion originated from intermolecular interaction between
the polyphenols of TA and mucin, exhibiting pH dependency. TAPE adhered
strongly to mucin in neutral conditions but bound weakly in acidic
conditions due to different hydrolysis rates of the ester linkages
in TA. Thus, TAPE might be useful as a long-lasting esophageal mucoadhesive
composite
Dynamic Bonds between Boronic Acid and Alginate: Hydrogels with Stretchable, Self-Healing, Stimuli-Responsive, Remoldable, and Adhesive Properties
For the increasing
demand of soft materials with wide ranges of
applications, hydrogels have been developed exhibiting variety of
functions (e.g., stretchable, self-healing, stimuli-responsive, and
etc.). So far, add-in components such as inorganic nanoparticles,
carbon materials, clays, and many others to main polymers have been
used to achieve various unique functions of hydrogels. The multicomponent
hydrogel systems often exhibit batch-dependent inconsistent results
and problems in multicomponent mixings, require labors during preparations,
and accompany unpredictable cross-talk between the added components.
Here, we developed ‘single polymeric component’, alginate-boronic
acid (alginate-BA) hydrogel to overcome the aforementioned problems.
It exhibits unprecedented multifunctionalities simultaneously, such
as high stretchability, self-healing, shear-thinning, pH- and glucose-sensitivities,
adhesive properties, and reshaping properties. Multifunctionalities
of alginate-BA hydrogel is resulted from the reversible inter- and
intramolecular interactions by dynamic equilibrium of boronic acid–diol
complexation and dissociation, which was proved by single molecule
level Atomic Force Microscopy (AFM) pulling experiments. We also found
that the alginate-BA gel showed enhanced in vivo retentions along
gastrointestinal (GI) tract. Our findings suggest that rational polymer
designs can result in minimizing the number of a participating component
for multifunctional hydrogels, instead of increasing complexity by
adding various additional components