Open-pore biodegradable foams with controlled porous architectures were prepared by combining gas foaming and microparticulate templating. Microparticulate composites of poly(epsilon-caprolactone) (PCL) and micrometric sodium chloride particles (NaCl), in concentrations ranging from 70/30 to 20/80 wt.-% of PCL/NaCl were melt-mixed and gas-foamed using carbon dioxide as physical blowing agent. The effects of microparticle concentration, foaming temperature, and pressure drop rate on foam microstructure were surveyed and related to the viscoelastic properties of the polymer/microparticle composite melt. Results showed that foams with open-pore networks can be obtained and that porosity, pore size, and interconnectivity may be finely modulated by optimizing the processing parameters. Furthermore, the ability to obtain a spatial gradient of porosity embossed within the three-dimensional polymer structure was exploited by using a heterogeneous microparticle filling. Results indicated that by foaming composites with microparticle concentration gradients, it was also possible to control the porosity and pore-size spatial distribution of the open-pore PCL foams.
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http://dx.doi.org/10.1002/mabi.200700278 | DOI Listing |
Proc Natl Acad Sci U S A
November 2024
Laboratory of Membrane Biology and Biophysics, The Rockefeller University, New York, NY 10065.
Protein kinase A (PKA) is a key regulator of cellular functions by selectively phosphorylating numerous substrates, including ion channels, enzymes, and transcription factors. It has long served as a model system for understanding the eukaryotic kinases. Using cryoelectron microscopy, we present complex structures of the PKA catalytic subunit (PKA-C) bound to a full-length protein substrate, the cystic fibrosis transmembrane conductance regulator (CFTR)-an ion channel vital to human health.
View Article and Find Full Text PDFEur Biophys J
November 2024
Department of Biophysics, Panjab University, Chandigarh, 160014, India.
Neuropathic pain (NP) is characterized by hyperalgesia, allodynia, and spontaneous pain. Hyperpolarization-activated cyclic nucleotide-gated (HCN) channel involved in neuronal hyperexcitability, has emerged as an important target for the drug development of NP. HCN channels exist in four different isoforms, where HCN1 is majorly expressed in dorsal root ganglion having an imperative role in NP pathophysiology.
View Article and Find Full Text PDFPflugers Arch
October 2024
Laboratory of Neurobiology, Graduate School of Integrated Sciences of Life, Hiroshima University, Kagamiyama 1-7-1, 739-8521, Higashi-Hiroshima, Japan.
The voltage-dependent potassium channels (Kv channels) show several different types of inactivation. N-type inactivation is a fast inactivating mechanism, which is essentially an open pore blockade by the amino-terminal structure of the channel itself or the auxiliary subunit. There are several functionally discriminatable slow inactivation (C-type, P-type, U-type), the mechanism of which is supposed to include rearrangement of the pore region.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
July 2024
Department of Biosciences, University of Milan, Milan 20133, Italy.
Zhongguo Zhong Yao Za Zhi
February 2024
Institute of Basic Medicine, Xiyuan Hospital, Chinese Academy of Chinese Medical Sciences Beijing 100091, China National Clinical Research Center for Chinese Medicine Cardiology Beijing 100091, China.
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