Protein Immobilization in PVA Hydrogel: A Synchrotron SAXS and FTIR Study

In the present work, we aimed to investigate the immobilization of Bovine Serum Albumin (BSA) into poly (vinyl alcohol) (PVA) network. PVA hydrogels with BSA were characterized by Synchrotron SAXS radiation associated with Fourier Transform Infrared Spectroscopy (FTIR). We synthesized hydrogels by dissolving PVA in aqueous solution (5.0 wt%) and crosslinked with glutaraldehyde (GA). PVA and PVA/GA hydrogels samples were immersed in BSA aqueous solution for protein immobilization. FTIR spectra showed major vibration bands associated with PVA and GA chemical groups, and BSA protein amides. Regarding to SAXS characterization, the slope of the log I(q), scattering intensity, as a function of log q, the scattering vector, provided important information about the morphology of entities present in the system. Two different scattering patterns were obtained for PVA (slope = 3.5) and PVA/BSA (slope=1.5 and 3.0). These results have given strong evidence of nano-ordered dispersed globular BSA immobilized into chemically crosslinked PVA hydrogel network. SAXS analyses have indicated that the scattering q-vector maximum value was shifted by altering PVA polymer hydrogel with GA crosslinker and also with BSA incorporation into the network.

Proper efficiency in linear vector maximum problems with nonlinear constraints

A linear vector maximum problem with nonlinear constraints is considered. A condition is derived which is necessary for an efficient solution and sufficient for a properly efficient solution of this problem. This leads to sufficient conditions for an efficient solution to be properly efficient. An example is discussed at the end.