Online Combination of Bioassays with Chemical and Structural Characterization for Detection of Bioactive Compounds

Author(s):  
Ana C. Freitas ◽  
Sofia Isabel G.H.M. Montalvão ◽  
Armando C. Duarte ◽  
Teresa Rocha-Santos
2019 ◽  
Vol 69 (12) ◽  
pp. 3756-3760 ◽  
Author(s):  
Simona Cavalu ◽  
Simona Bisboaca ◽  
Ileana Mariana Mates ◽  
Paula Melania Pasca ◽  
Vasile Laslo ◽  
...  

The aim of our study was to prepare and characterize chitosan-based nanoparticles encapsulating propolis extract by ionotropic gelation and glutaraldehyde cross-linking technique. Both spectroscopic (UV-Vis, FTIR) and microscopic techniques (AFM) were applied for structural characterization of nanoparticles, along with entrapment and release study of propolis extract. The physico-chemical properties and morphological features of the obtained nanoparticles demonstrated a good correlation between all the investigated methods. Moreover, the bioactive compounds were stable upon the encapsulation procedure. Propolis release from the polymeric matrix was monitored in both simulated gastric acid and simulated intestinal fluids, concluding that our proposed formulation is suitable for controlled release. These results may provide a novel design, with improved bioavailability, stability and nutritional value of propolis bioactive compounds during processing and storage, with possible applications in food and nutraceutical industries.


Author(s):  
E. Naranjo

Equilibrium vesicles, those which are the stable form of aggregation and form spontaneously on mixing surfactant with water, have never been demonstrated in single component bilayers and only rarely in lipid or surfactant mixtures. Designing a simple and general method for producing spontaneous and stable vesicles depends on a better understanding of the thermodynamics of aggregation, the interplay of intermolecular forces in surfactants, and an efficient way of doing structural characterization in dynamic systems.


Author(s):  
S. F. Hayes ◽  
M. D. Corwin ◽  
T. G. Schwan ◽  
D. W. Dorward ◽  
W. Burgdorfer

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.


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