An investigation of alkaline phosphatase enzymatic activity after electrospinning and electrospraying

Abstract

The high target specificity and multifunctionality of proteins has led to great interest in their clinical use. To this end, the development of delivery systems capable of preserving their bioactivity and improving bioavailability is pivotal to achieve high effectiveness and satisfactory therapeutic outcomes. Electrohydrodynamic (EHD) techniques, namely electrospinning and electrospraying, have been widely explored for protein encapsulation and delivery. In this work, monoaxial and coaxial electrospinning and electrospraying were used to encapsulate alkaline phosphatase (ALP) into poly(ethylene oxide) fibres and particles, respectively, and the effects of the processing techniques on the integrity and bioactivity of the enzyme were assessed. A full morphological and physicochemical characterisation of the blend and core-shell products was performed. ALP was successfully encapsulated within monolithic and core-shell electrospun fibres and electrosprayed particles, with drug loadings and encapsulation efficiencies of up to 21% and 99%, respectively. Monoaxial and coaxial electrospinning were equally effective in preserving ALP function, leading to no activity loss compared to fresh aqueous solutions of the enzyme. While the same result was observed for monoaxial electrospraying, coaxial electrospraying of ALP caused a 40% reduction in its bioactivity, which was attributed to the high voltage (22.5 kV) used during processing. This demonstrates that choosing between blend and coaxial EHD processing for protein encapsulation is not always straightforward, being highly dependent on the chosen therapeutic agent and the effects of the processing conditions on its bioactivity.

Electrospun PAN/PEG Nanofibrous Membrane Embedded with a MgO/gC3N4 Nanocomposite for Effective Bone Regeneration

“…The ALP activity for the 24 h culture period shows that the modified nanofiber membrane has higher activity by normalizing the DNA of MG-63 cells at 170.74 U/L. The ALP activity of the modified nanofiber membrane is 54.99% higher than that of the bare membrane. , This remarkable increase in mineralization is due to the incorporation of MgO/gC 3 N 4 nanocomposites into PAN/PEG. Also, the PEG rich in OH groups can initiate the increase of viability in cells.…”

“…The ALP activity of the modified nanofiber membrane is 54.99% higher than that of the bare membrane. 49,50 This remarkable increase in mineralization is due to the incorporation of MgO/gC 3 N 4 nanocomposites into PAN/PEG. Also, the PEG rich in OH groups can initiate the increase of viability in cells.…”

Stable Dried Catalase Particles Prepared by Electrospraying

“…Monoaxial or blend EHD is achieved from a single solution where all components are mixed, whereas with co-axial EHD, a two-needle spinneret allows the production of core–shell structures from two separated solutions. Thus, with co-axial EHD, biomolecules can be protected from potential solvent induced denaturation and loss of function minimised, whereas the blend process often leads to denaturation and loss in bioactivity due to the harsh environment (e.g., organic solvents) [ 20 , 21 ]. However, co-axial EHD is more complex compared with the blend process, making it more challenging to scale up [ 3 , 20 ].…”

“…Thus, with co-axial EHD, biomolecules can be protected from potential solvent induced denaturation and loss of function minimised, whereas the blend process often leads to denaturation and loss in bioactivity due to the harsh environment (e.g., organic solvents) [ 20 , 21 ]. However, co-axial EHD is more complex compared with the blend process, making it more challenging to scale up [ 3 , 20 ]. Onyekuru et al have shown that proteins such as alkaline phosphatase can be processed by EHD into fibres and particles without loss of activity, even for blend solutions [ 20 ].…”

“…However, co-axial EHD is more complex compared with the blend process, making it more challenging to scale up [ 3 , 20 ]. Onyekuru et al have shown that proteins such as alkaline phosphatase can be processed by EHD into fibres and particles without loss of activity, even for blend solutions [ 20 ]. In fact, the blend electrospraying process maintained the integrity of alkaline phosphatase, whereas the co-axial process resulted in partial loss of activity, which was attributed to the high voltage that was required for the process [ 20 ].…”