title: Measuring wettability of biosurfaces at the microscale.
abstract: Determining the contact angle of a liquid on a solid surface is a simple method to assess the surface wettability. The most common method to measure the contact angle of a liquid consists of capturing the profile of a sessile drop of a few microliters on the surface using an optical system. Currently, this is a widely used technique to analyze wettability both in researched materials and in products of multiple technological fields. However, the drop dispensed by a traditional macroscopic contact angle meter is too big to assess the wettability properties of individual topographical features and/or chemical patterns at the micro/nanoscale. Recently, contact angle meters that can discharge drops that are microscopic, with volumes in the range of 1 × 10(-3) to 10(-5) μL have been developed. The novel microscopic contact angle meter uses a pneumatic injection system to discharge the drop of the liquid through a capillary of a few micrometers of internal diameter and a high-resolution ultrafast digital camera. We have tested different biosurfaces - microimprinted polymers for biosensors, calcium-phosphate cements with different topographical microfeatures, orthodontic wires - and assessed the potential applicability in the field in comparison with the conventional macroscopic contact angle meters. This protocol describes the basic tasks needed to test wettability on biosurfaces with a microscopic contact angle meter. The focus of the protocol is on the challenging methodological steps and those that differentiate the use of this equipment to the use of a traditional macroscopic contact angle meter.
authors: Department of Restorative Sciences, Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN, USA. apari003@umn.edu
authors: Conrado
authors: C
authors: Aparicio
authors: Yassine
authors: Y
authors: Maazouz
authors: Dehua
authors: D
authors: Yang
mesh_terms: D015374:Biosensing Techniques; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods*; D002130:Calcium Phosphates / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation / Q000379:methods*; D009969:Orthodontic Wires; D011108:Polymers / Q000737:chemistry; D044968:Regenerative Medicine / Q000295:instrumentation / Q000379:methods*; D017155:Wettability
chemical_list: D002130:Calcium Phosphates; D011108:Polymers