Measuring contact angles on hydrophilic porous scaffolds by implementing a novel raised platform approach: A technical note

Abstract

Contact angle (CA) analysis is a widely employed technique to assess the surface properties of solid samples, including in tissue engineering research where scaffolds are typically designed to be both porous and hydrophilic to enable cell and tissue infiltration. Paradoxically, the types of scaffolds that possess the most optimal hydrophilic surface properties for cell attachment are the most challenging surfaces to attain accurate CA measurements. Here, we propose the use of a small 3D printed platform to elevate samples above the CA measurement substrate and demonstrate reproducible and accurate CA measurements on a range of popular polymer scaffolds that had undergone 5 min plasma treatment to instigate hydrophilicity. Using four polycaprolactone or high-density polyethylene scaffolds with porosity ranging from 35.8%-93.1%, 0 CAs were reproducibly observed by measuring the CA while the scaffolds were elevated on the 3D printed platform, compared to the highly variable false-positive results when measuring the scaffolds while directly sitting on measurement substrates of various materials. This versatile, low-cost modification to CA hardware overcomes the challenges associated with measuring the surface properties of porous, hydrophilic scaffolds and provides a simple tool for tissue engineering researchers to perform CA measurements for any biomaterial scaffolds to ascertain hydrophilicity which is used to infer the suitability of scaffold surfaces for cell attachment.

Nanoscale Porosity in Microellipsoids Cloaks Interparticle Capillary Attraction at Fluid Interfaces

“…As with liquid infiltrating any porous media, the driving force is a Laplace pressure that depends on the interfacial tension, contact angle, and size of the pores. This liquid infiltration obfuscates the actual three-phase contact angle 76 , 77 (as seen in the increase in contact angle in the sessile drop results in Figure S12 ) and also contributes to the interfacial rise detected by interferometry. Millimeter-scale porous supra-particles have been synthesized by careful evaporation of dense suspensions of micron-scale polystyrene particles, 78 and associated theory and experiments examining their attachment to oil–water interfaces show that supra-particles adsorb to the interface with different macroscopic contact angles depending on whether they adsorb to the interface from the water-infused or oil-infused state.…”

Fabrication, Characterization, and Biocompatibility Study of Gelatin-Blended Fibroin Scaffold

“…For the WAXS result, the crystallinity of formula ratios of fibroin:gelatin at 7:3 was slightly higher than that of fibroin: gelatin at 8:2. The gelatin induced fibroin conformational conversion from random coil to beta crystal [20]. Therefore, the presence of gelatin influences gelatin-blended gelatin-blended fibroin scaffold crystallization.…”

Highly compliant biomimetic scaffolds for small diameter tissue-engineered vascular grafts (TEVGs) produced via melt electrowriting (MEW)

“…Firstly, scaffold samples were treated with O 2 /Ar 2 (15/5) plasma for 2 min at 38 W in a vacuum plasma cleaner (PDC-002-HP, Harrick Plasma, USA) to induce hydrophilicity within PCL scaffolds prior to cell seeding. The protocol was developed in accordance with published methods for the plasma treatment of PCL scaffolds; whereby exposure to plasma for 2 min was shown to induce complete scaffold wettability suitable for cell suspension infiltration, while only reported to affect a minimal 11% increase in tensile modulus and negligible change in polymer crystallinity, when compared to untreated PCL scaffolds produced via MEW [38,39].…”