TY  - JOUR
A1  - Federico, Stefania
A1  - Nöchel, Ulrich
A1  - Löwenberg, Candy
A1  - Lendlein, Andreas
A1  - Neffe, Axel T.
T1  - Supramolecular hydrogel networks formed by molecular recognition of collagen and a peptide grafted to hyaluronic acid
JF  - Acta biomaterialia
N2  - The extracellular matrix (ECM) is a nano-structured, highly complex hydrogel, in which the macromolecules are organized primarily by non-covalent interactions. Here, in a biomimetic approach, the decorin-derived collagen-binding peptide LSELRLHNN was grafted to hyaluronic acid (HA) in order to enable the formation of a supramolecular hydrogel network together with collagen. The storage modulus of a mixture of collagen and HA was increased by more than one order of magnitude (G′ = 157 Pa) in the presence of the HA-grafted peptide compared to a mixture of collagen and HA (G′ = 6 Pa). The collagen fibril diameter was decreased, as quantified using electron microscopy, in the presence of the HA-grafted peptide. Here, the peptide mimicked the function of decorin by spatially organizing collagen. The advantage of this approach is that the non-covalent crosslinks between collagen molecules and the HA chains created by the peptide form a reversible and dynamic hydrogel, which could be employed for a diverse range of applications in regenerative medicine.
Statement of Significance

Biopolymers of the extracellular matrix (ECM) like collagen or hyaluronan are attractive starting materials for biomaterials. While in biomaterial science covalent crosslinking is often employed, in the native ECM, stabilization and macromolecular organization is primarily based on non-covalent interactions, which allows dynamic changes of the materials. Here, we show that collagen-binding peptides, derived from the small proteoglycan decorin, grafted to hyaluronic acid enable supramolecular stabilization of collagen hydrogels. These hydrogels have storage moduli more than one order of magnitude higher than mixtures of collagen and hyaluronic acid. Furthermore, the peptide supported the structural organization of collagen. Such hydrogels could be employed for a diverse range of applications in regenerative medicine. Furthermore, the rational design helps in the understanding ECM structuring.
KW  - Biopolymers
KW  - Collagen-binding peptide
KW  - Hyaluronic acid
KW  - Hydrogels
KW  - Mechanical properties
Y1  - 2016
U6  - https://doi.org/10.1016/j.actbio.2016.04.018
SN  - 1742-7061
SN  - 1878-7568
VL  - 38
SP  - 1
EP  - 10
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Kyriakos, Konstantinos
A1  - Aravopoulou, Dionysia
A1  - Augsbach, Lukas
A1  - Sapper, Josef
A1  - Ottinger, Sarah
A1  - Psylla, Christina
A1  - Rafat, Ali Aghebat
A1  - Benitez-Montoya, Carlos Adrian
A1  - Miasnikova, Anna
A1  - Di, Zhenyu
A1  - Laschewsky, André
A1  - Müller-Buschbaum, Peter
A1  - Kyritsis, Apostolos
A1  - Papadakis, Christine M.
T1  - Novel thermoresponsive block copolymers having different architectures-structural, rheological, thermal, and dielectric investigations
JF  - Colloid and polymer science : official journal of the Kolloid-Gesellschaft
N2  - Thermoresponsive block copolymers comprising long, hydrophilic, nonionic poly(methoxy diethylene glycol acrylate) (PMDEGA) blocks and short hydrophobic polystyrene (PS) blocks are investigated in aqueous solution. Various architectures, namely diblock, triblock, and starblock copolymers are studied as well as a PMDEGA homopolymer as reference, over a wide concentration range. For specific characterization methods, polymers were labeled, either by partial deuteration (for neutron scattering studies) or by fluorophores. Using fluorescence correlation spectroscopy, critical micellization concentrations are identified and the hydrodynamic radii of the micelles, r (h) (mic) , are determined. Using dynamic light scattering, the behavior of r (h) (mic) in dependence on temperature and the cloud points are measured. Small-angle neutron scattering enabled the detailed structural investigation of the micelles and their aggregates below and above the cloud point. Viscosity measurements are carried out to determine the activation energies in dependence on the molecular architecture. Differential scanning calorimetry at high polymer concentration reveals the glass transition of the polymers, the fraction of uncrystallized water and effects of the phase transition at the cloud point. Dielectric relaxation spectroscopy shows that the polarization changes reversibly at the cloud point, which reflects the formation of large aggregates upon heating through the cloud point and their redissolution upon cooling.
KW  - Block copolymers
KW  - Thermoresponsive
KW  - Structural investigations
KW  - Mechanical properties
KW  - Thermal behavior
KW  - Dielectric properties
Y1  - 2014
U6  - https://doi.org/10.1007/s00396-014-3282-0
SN  - 0303-402X
SN  - 1435-1536
VL  - 292
IS  - 8
SP  - 1757
EP  - 1774
PB  - Springer
CY  - New York
ER  -