Making novel bio-interfaces through bacterial protein recrystallization on biocompatible polylactide derivative films
Fabrication of novel bio-supramolecular structures was achieved by recrystallizing the bacterial surface protein SbpA on amorphous and semicrystalline polylactide derivatives. Differential scanning calorimetry showed that the glass transition temperature (Tg) for (poly-L-lactide)-PLLA, poly (L,D- la...
| Authors: | , , , , |
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| Format: | article |
| Publication Date: | 2013 |
| Country: | España |
| Institution: | Universidad del País Vasco |
| Repository: | Addi. Archivo Digital para la Docencia y la Investigación |
| OAI Identifier: | oai:addi.ehu.eus:10810/76042 |
| Online Access: | http://hdl.handle.net/10810/76042 |
| Access Level: | Open access |
| Keyword: | biopolymers S-layers biomimetics young modulus glass transition temperature atomic force microscopy quartz crystal microbalance |
| Summary: | Fabrication of novel bio-supramolecular structures was achieved by recrystallizing the bacterial surface protein SbpA on amorphous and semicrystalline polylactide derivatives. Differential scanning calorimetry showed that the glass transition temperature (Tg) for (poly-L-lactide)-PLLA, poly (L,D- lactide)-PDLLA, Poly(lactide-co-glycolide)-PLGA and poly (lactide-co-caprolactone)-PLCL was 63ºC, 53ºC, 49ºC and 15ºC, respectively. Tensile stress-strain tests indicated that PLLA, PLGA and PDLLA had a glassy behaviour when tested below Tg. The obtained Young modulus were 1477 MPa, 1330 MPa, 1306 MPa and 9.55 MPa for PLLA, PLGA, PDLLA and PLCL respectively. AFM results confirmed that SbpA recrystallized on every polymer substrate exhibiting the native S-layer P4 lattice (a = b = 13 nm, = 90). However, the polymer substrate influenced the domain size of the S-protein crystal, with the smallest size for PLLA (0.011 m2), followed by PDLLA (0.034 m2) and PLGA (0.039 m2), and the largest size for PLCL (0.09 m2). QCM-D measurements indicated that the adsorbed protein mass per unit area (ca. 1800 ng cm-2) was independent of the mechanical, thermal and crystalline properties of the polymer support. The slowest protein adsorption rate was observed for amorphous PLCL (the polymer with the weakest mechanical properties and lowest Tg). QCM-D also monitored protein self-assembly in solution and confirmed that S-layer formation takes place in three main steps: adsorption, self-assembly and crystal reorganization. Finally, this work shows that biodegradable polylactide derivatives films are a suitable support to form robust biomimetic S-protein layers. |
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