4 research outputs found
Microhydration of Biomolecules: Revealing the Native Structures by Cold Ion IR Spectroscopy
The native-like structures of protonated glycine and peptide Gly3H+ were elucidated using cold ion IR spectroscopy of these biomolecules hydrated by a controlled number of water molecules. The complexes were generated directly from an aqueous solution using gentle electrospray ionization. Already with a single retained water molecule, GlyH+ exhibits the native-like structure characterized by a lack of intramolecular hydrogen bonds. We use our spectra to calibrate the available data for the same complexes, which are produced by cryogenic condensation of water onto the gas-phase glycine. In some conformers of these complexes, GlyH+ adopts the native-like structure, while in the others, it remains “kinetically” trapped in the intrinsic state. Upon condensation of 4–5 water molecules, the embedded amino acid fully adopts its native-like structure. Similarly, condensation of one water molecule onto the tripeptide is insufficient to fully eliminate its kinetically trapped intrinsic states
Salt Bridge Structure of Microhydrated Arginine Kinetically Trapped in the Gas Phase by Evaporative Cooling
Enhanced piezoelectric response of hybrid biodegradable 3D poly(3-hydroxybutyrate) scaffolds coated with hydrothermally deposited ZnO for biomedical applications
Fibrous scaffolds based on biodegradable piezoelectric poly(3-hydroxybutyrate) (PHB) polymers were fabricated via electrospinning. Hydrothermal deposition of zinc oxide (ZnO) on the surfaces of fibrous PHB scaffolds resulted in a homogeneous ZnO layer that grew conformally on the porous polymeric scaffold. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results confirmed the formation of a hexagonal wurtzite crystal structure of ZnO on the PHB fibres. XRD patterns, TEM and EDS analysis revealed a bimodal morphology with rod-like nanostructures that grew preferentially along the c-axis as well as nanoparticles that grew randomly. The piezoelectric charge coefficient d(33) for pristine PHB scaffolds was 2.9 +/- 0.1 pC.N-1, whereas after ZnO deposition, it substantially increased to 13.7 +/- 1.6 pC.N-1. Moreover, the output surface electrical potential of PHB scaffolds after ZnO deposition also substantially increased from 0.58 +/- 0.02 to 0.88 +/- 0.04 V, showing enhanced electromechanical coupling in the piezoelectric nanocomposites. The output surface electric potential for ZnO-coated PHB scaffolds was stable within 1200 loading cycles. In addition, the ZnO rod-like nanostructured surface improved the wettability of PHB fibrous scaffolds, demonstrating synergy between the ceramic and polymeric phases in PHB/ZnO composites. Therefore, the hybrid biodegradable piezoelectric scaffolds reported in the present study are potentially useful for biomedical applications, where both improved piezoelectric response and surface wettability are required