Abstract
Aquaporin incorporated biomimetic membranes are anticipated to offer unprecedented desalination capabilities. However, the lack of accurate methods to quantify the reconstituted aquaporin presents a huge hurdle in investigating aquaporin performance and optimizing membrane fabrication. Herein, we present three quantification methods to determine the Aquaporin-Z reconstituted into E. coli lipid vesicles: 1) nanogold labeling with transmission electron microscopy (TEM) visualization, 2) nickel labeling with inductively coupled plasma-mass spectrometry (ICP-MS) and 3) gel electrophoresis. The TEM method serves as a quick way to determine if aquaporin has been reconstituted, but is not quantitative. The numerical results from quantitative methods, ICP-MS and gel electrophoresis, correlate closely, showing that 60 ± 20% vs 66 ± 4% of Aquaporin-Z added is successfully reconstituted into vesicles respectively. These methods allow more accurate determination of Aquaporin-Z reconstituted and loss during reconstitution, with relatively commonly available equipment and without complex sample handling, or lengthy data analysis. These would allow them to be widely applicable to scientific studies of protein function in the biomimetic environment and engineering studies on biomimetic membrane fabrication.
Highlights
Reverse osmosis is the leading technology in water desalination
The effectiveness of AqpZ reconstitution was first evaluated with conventional methods, stopped-flow light scattering (SFLS) permeability test and dynamic light scattering (DLS)
Successful AqpZ incorporation is evident from the results of SFLS functional assay (Fig. 2 and Table 1), which shows a marked increase in vesicle permeability from 24 μm/s to 800 μm/s with AqpZ addition
Summary
Reverse osmosis is the leading technology in water desalination. The burgeoning need for water has fueled the search for higher performance membrane that can reduce the energy consumption and cost of reverse osmosis process[1]. Aqp is the main component that distinguishes a biomimetic membrane from a conventional membrane, yet the actual amount of Aqp reconstituted is often neglected due to the lack of quantification methods. This hinders systematic understanding of the intricate works of the biomimetic membrane, which is vital for scientific exploration and membrane performance optimization. There has been an attempt to answer the need for quantification of Aqp reconstituted by the Danish company Aquaporin A/S19 They have presented several quantification methods including freeze-fracture transmission electron microscopy (FF-TEM), fluorescence correlation spectroscopy (FCS) and small-angle X-ray scattering (SAXS)[19]. The latter two methods can provide detailed information but require access to large-scale facilities and knowledge in modelling and fitting for data progressing
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
