Pendant-drop method coupled to ultraviolet-visible spectroscopy: A useful tool to investigate interfacial phenomena

Author(s)

Andrade, Marco A. R. ; Favarin, Bruno ; Derradi, Rafael ; Bolean, Mayte ; Simao, Ana Maria S. ; Millan, Jose Luis ; Ciancaglini, Pietro ; Ramos, Ana P.

• Document type: Journal article
• Source: COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS; v. 504, p. 305-311, SEP 5 2016.
• Web of Science Citations: 3

Abstract

UV-vis spectroscopy is a powerful tool to investigate surface phenomena. Surface tension measurements coupled to spectroscopic techniques can help to elucidate how the interface organization influences the electronic properties of molecules. However, appreciable sample volumes are usually necessary to achieve strong signals during conduction of experiments. This study reports on the simultaneous acquisition of surface tension data and UV-vis spectra by axisymmetric drop shape analysis (ADSA) coupled to diffuse reflectance (DRUV) spectrophotometry using a pendant microliter-drop that requires small sample volumes and low analyte concentrations. Three example systems gave evidence of the applicability of this technique: (a) disaggregation of an organic dye driven by surfactant as a function of the surface tension and alterations in the UV-vis spectra, (b) activity of a glycosylphosphatidylinositol anchored enzyme estimated from formation of a colored product, and (c) interaction between this enzyme and biomimetic membrane systems consisting of dipalmitoylphosphaditylcholine and cholestenone. Apart from using smaller sample volume, this coupled technique allowed to investigate interfacial organization in the light of electronic spectra obtained in loco within a shorter acquisition time. This procedure provided precise interfacial information about static and dynamic systems. This has been the first study describing the kinetic activity of an enzyme in the presence of phospholipid monolayers through simultaneous determination of the surface tension and UV-vis spectra. (C) 2016 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 14/11941-3 - Are collagen and Annexin V responsible for the control in the biomineralization process?
• Grantee: Pietro Ciancaglini
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/20946-3 - Study of the growth of calcium phosphates and carbonates on organic matrices deposited on mettalic supports: obtainment of osteoinductive biomaterials
• Grantee: Ana Paula Ramos
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/00345-3 - Lipid microdomains in Langmuir-Blodgett films rich in alkaline phosphatase to obtain a Ti surface osteoinductive
• Grantee: Marco Aurélio Raz de Andrade
• Support Opportunities: Scholarships in Brazil - Master