Preparation and Properties of a Chitosan–Hyaluronic
Acid-Polypyrrole Conductive Hydrogel Catalyzed by Laccase
Published online: 15 September 2016
Ó Springer Science+Business Media New York 2016
Abstract Electro conductive hydrogels, consisting of chi-
tosan (CS), hyaluronic acid (HA), and polypyrrole (PPy),
were prepared via an in situ enzymic polymerization of
pyrrole in the CS–HA hydrogel, using laccase as the cat-
alyst. This CS–HA–PPy composite hydrogel showed good
conductivity. The chemical structure and morphology of
this conductive hydrogel were studied by Fourier transform
infrared spectroscopy, scanning electron microscopy, and
X-ray diffraction technique. For CS–HA–PPy and CH–HA
hydrogel, the temperature at which fastest decomposition
occurred was 260 and 244 °C, respectively. That means the
thermal stability of CS–HA–PPy is better than CS–HA
hydrogel. The conductive hydrogel also showed excellent
swelling and deswelling behaviors.
Keywords Biopolymers Á Conductivity Á Enzymes Á Gels
Hydrogel is a polymeric network system, which has the
capacity to imbibe a large amount of biological ﬂuid or
water and retain it, even under mechanical pressure.
Hydrogels possess many interesting features such as
thermo-reversibility, high tunability, stimuli-responsive
behavior, biodegradable and biocompatible . Hydrogels
have potential application in dye absorbent, drug release,
engineering cell microenvironment, wound closure, tissue
engineering and so on [2–7].
Currently, amongst the smart hydrogels, conductive
hydrogels have attracted tremendous attention, because they
exhibit two important features: the swelling behavior of
hydrogels and the electricity conducting properties of con-
ductive polymers . Stimuli-responsive conductive hydro-
gels have promising applications in various ﬁelds such as
electrical, electrochemical and biomedical devices [9–11].
A conductive hydrogel can be prepared in many ways,
such as by adding conducting particles to the gel matrix,
producing gels directly from conducting polymers, incor-
porating conducting polymers into the network structure of
gels, or by in situ polymerization of the conducting
monomers inside the gel matrix . The chemical sub-
stances are usually used as the catalysts in all these
preparation methods .
This paper represents a CS–HA–PPy conductive com-
posite hydrogel, synthesized via an in situ polymerization
of conducting monomers (pyrrole), inside the gel matrix of
a natural polymer, by an environment-friendly and efﬁcient
method (enzymatic polymerization). Another advantage of
this method is that it does not require strong acids or
puriﬁcation steps in the synthesis process.
Chitosan (CS), a polysaccharide consisting of (1 ? 4)-2-
(1 ? 4)-2-amino-2-deoxy-b-
is the second most abundant natural biopolymer, after cellulose.
CS hydrogels have been used in different forms, such as scaf-
folds for cartilage or bone in tissue engineering, cell culture
supports, bio-separation devices, sensors, or actuator systems
[14, 15]. However, their applications are limited due to their
poor mechanical strengths, which reduce their usefulness .
Hyaluronic acid (HA), a highly anionic and hydrated polyan-
ionic macromolecule consists of repeating (1 ? 4)-b-
& Ying Zhang
Key Laboratory of Science and Technology of Eco-Textile,
Ministry of Education, Jiangnan University,
Wuxi 214122, Jiangsu, China
J Polym Environ (2017) 25:526–532