TY  - JOUR
A1  - Rojas, Oscar
A1  - Tiersch, Brigitte
A1  - Rabe, Christian
A1  - Stehle, Ralf
A1  - Hoell, Armin
A1  - Arlt, Bastian
A1  - Koetz, Joachim
T1  - Nonaqueous Microemulsions Based on N,N '-Alkylimidazolium Alkylsulfate Ionic Liquids
JF  - Langmuir
N2  - The ternary system composed of the ionic liquid surfactant (IL-S) 1-butyl-3-methylimidazolium dodecylsulfate ([Bmim][DodSO(4)]), the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtSO4]), and toluene has been investigated. Three major mechanisms guiding the structure of the isotropic phase were identified by means of conductometric experiments, which have been correlated to the presence of oil-in-IL, bicontinuous, and IL-in-oil microemulsions. IL-S forms micelles in toluene, which swell by adding RTIL as to be shown by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) experiments. Therefore, it is possible to form water free IL-in-oil reverse microemulsions <= 10 nm in size as a new type of nanoreactor.
Y1  - 2013
U6  - https://doi.org/10.1021/la401080q
SN  - 0743-7463
VL  - 29
IS  - 23
SP  - 6833
EP  - 6839
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Dolya, Natalya
A1  - Rojas, Oscar
A1  - Kosmella, Sabine
A1  - Tiersch, Brigitte
A1  - Koetz, Joachim
A1  - Kudaibergenov, Sarkyt
T1  - "One-Pot" in situ frmation of Gold Nanoparticles within Poly(acrylamide) Hydrogels
JF  - Macromolecular chemistry and physics
N2  - This paper focuses on two different strategies to incorporate gold nanoparticles (AuNPs) into the matrix of polyacrylamide (PAAm) hydrogels. Poly(ethyleneimine) (PEI) is used as both reducing and stabilizing agent for the formation of AuNPs. In addition, the influence of an ionic liquid (IL) (i.e., 1-ethyl-3-methylimidazolium ethylsulfate) on the stability of the nanoparticles and their immobilization in the hydrogel is investigated The results show that AuNPs surrounded by a shell containing PEI and IL, synthesized according to the one-pot approach, are much better immobilized within the PAAm hydrogel. Hereby, the IL is responsible for structural changes in the hydrogel as well as the improved stabilization and embedding of the AuNPs into the polymer gel matrix.
KW  - gold nanoparticles
KW  - immobilization
KW  - ionic liquids
KW  - poly(acrylamide) hydrogels
Y1  - 2013
U6  - https://doi.org/10.1002/macp.201200727
SN  - 1022-1352
VL  - 214
IS  - 10
SP  - 1114
EP  - 1121
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Bertz, Andreas
A1  - Wöhl-Bruhn, Stefanie
A1  - Miethe, Sebastian
A1  - Tiersch, Brigitte
A1  - Koetz, Joachim
A1  - Hust, Michael
A1  - Bunjes, Heike
A1  - Menzel, Henning
T1  - Encapsulation of proteins in hydrogel carrier systems for controlled drug delivery influence of network structure and drug size on release rate
JF  - Journal of biotechnology
N2  - Novel hydrogels based on hydroxyethyl starch modified with polyethylene glycol methacrylate (HES-P(EG)(6)MA) were developed as delivery system for the controlled release of proteins. Since the drug release behavior is supposed to be related to the pore structure of the hydrogel network the pore sizes were determined by cryo-SEM, which is a mild technique for imaging on a nanometer scale. The results showed a decreasing pore size and an increase in pore homogeneity with increasing polymer concentration. Furthermore, the mesh sizes of the hydrogels were calculated based on swelling data. Pore and mesh size were significantly different which indicates that both structures are present in the hydrogel. The resulting structural model was correlated with release data for bulk hydrogel cylinders loaded with FITC-dextran and hydrogel microspheres loaded with FITC-IgG and FITC-dextran of different molecular size. The initial release depended much on the relation between hydrodynamic diameter and pore size while the long term release of the incorporated substances was predominantly controlled by degradation of the network of the much smaller meshes.
KW  - Hydrogel
KW  - Hydrogel microspheres
KW  - Network structure
KW  - Release studies
KW  - Protein delivery
KW  - Mesh size
Y1  - 2013
U6  - https://doi.org/10.1016/j.jbiotec.2012.06.036
SN  - 0168-1656
VL  - 163
IS  - 2
SP  - 243
EP  - 249
PB  - Elsevier
CY  - Amsterdam
ER  -