TY  - JOUR
A1  - Tartivel, Lucile
A1  - Blocki, Anna M.
A1  - Braune, Steffen
A1  - Jung, Friedrich
A1  - Behl, Marc
A1  - Lendlein, Andreas
T1  - An Inverse shape-memory hydrogel scaffold switching upon cooling in a tissue-tolerated temperature range
JF  - Advanced materials interfaces
N2  - Tissue reconstruction has an unmet need for soft active scaffolds that enable gentle loading with regeneration-directing bioactive components by soaking up but also provide macroscopic dimensional stability. Here microporous hydrogels capable of an inverse shape-memory effect (iSME) are described, which in contrast to classical shape-memory polymers (SMPs) recover their permanent shape upon cooling. These hydrogels are designed as covalently photo cross-linked polymer networks with oligo(ethylene glycol)-oligo(propylene glycol)-oligo(ethylene glycol) (OEG-OPG-OEG) segments. When heated after deformation, the OEG-OPG-OEG segments form micelles fixing the temporary shape. Upon cooling, the micelles dissociate again, the deformation is reversed and the permanent shape is obtained. Applicability of this iSME is demonstrated by the gentle loading of platelet-rich plasma (PRP) without causing any platelet activation during this process. PRP is highly bioactive and is widely acknowledged for its regenerative effects. Hence, the microporous inverse shape-memory hydrogel (iSMH) with a cooling induced pore-size effect represents a promising candidate scaffold for tissue regeneration for potential usage in minimally invasive surgery applications.
KW  - active scaffold
KW  - critical micellation temperature
KW  - hydrogel
KW  - inverse
KW  - shape-memory effect
KW  - platelet-rich plasma
Y1  - 2022
U6  - https://doi.org/10.1002/admi.202101588
SN  - 2196-7350
VL  - 9
IS  - 6
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Zhang, Pengfei
A1  - Behl, Marc
A1  - Balk, Maria
A1  - Peng, Xingzhou
A1  - Lendlein, Andreas
T1  - Shape-programmable architectured hydrogels sensitive to ultrasound
JF  - Macromolecular rapid communications
N2  - On-demand motion of highly swollen polymer systems can be triggered by changes in pH, ion concentrations, or by heat. Here, shape-programmable, architectured hydrogels are introduced, which respond to ultrasonic-cavitation-based mechanical forces (CMF) by directed macroscopic movements. The concept is the implementation and sequential coupling of multiple functions (swellability in water, sensitivity to ultrasound, shape programmability, and shape-memory) in a semi-interpenetrating polymer network (s-IPN). The semi-IPN-based hydrogels are designed to function through rhodium coordination (Rh-s-IPNH). These coordination bonds act as temporary crosslinks. The porous hydrogels with coordination bonds (degree of swelling from 300 +/- 10 to 680 +/- 60) exhibit tensile strength sigma(max) up to 250 +/- 60 kPa. Shape fixity ratios up to 90% and shape recovery ratios up to 94% are reached. Potential applications are switches or mechanosensors.
KW  - cavitation-based mechanical force
KW  - rhodium-phosphine coordination bonds
KW  - semi-IPN hydrogels
KW  - shape-memory effect
Y1  - 2020
U6  - https://doi.org/10.1002/marc.201900658
SN  - 1022-1336
SN  - 1521-3927
VL  - 41
IS  - 7
PB  - Wiley-VCH
CY  - Weinheim
ER  -