Purpose: The production of nano-erythrosomes (NEs) by extrusion, which is considered the "gold standard", has several disadvantages such as difficult equipment assembly, long procedure time, variable pressure, and problems with sterility. An alternative approach, using ultrasound probe, has been shown to overheat the sample and have suboptimal results compared to the extrusion method. In our study, we propose, develop, and test a new method for the fabrication of NEs based on shear force and then compare it to the "gold standard" extrusion approach.
Methods: The new method consists of mechanical shear force disruption of the hemoglobin-depleted erythrocyte ghost membranes, with the aid of a rotor stator based tissue homogenizer. Using the same batches of erythrocyte ghost membranes, we compared NEs produced by shear force to NEs produced by the well-established extrusion approach. NEs were characterized for yield, size, encapsulation efficiency, morphology, and stability by flow cytometry (FC), transmission electron microscopy (TEM), and zeta potential analysis.
Results: The shear force based process was easier to set up, significantly faster, had better sterility control, and decreased variability between batches. The shear force method generated NEs with the desired size distribution (particles diameter ~125 nm), which were morphologically and functionally equivalent to the NEs produced by extrusion. NEs produced by shear force were stable in terms of counts, size, and fluorescence intensity for 3 weeks at +4°C. Moreover, they showed colloidal stability and minimal influence to centrifugal stress, turbulence shock, and hemolytic potential.
Conclusion: The newly proposed shear force method allows faster, easier, and highly reproducible NEs production when compared to the conventional extrusion approach. The new setup allows simultaneous production of sterile batches of NEs, which have homogenous size distribution, good stability, and improved shelf life storage. The ability of the shear force method to process also high concentration samples indicates a future potential development of large-scale NEs production and industrial application, which has been a challenge for the extrusion method.
Keywords: erythrocytes; extrusion; nanoerythrosomes; nanotechnology; new method; shear force.
© 2020 Capossela et al.