Self-assembled carrageenan/protamine polyelectrolyte nanoplexes—Investigation of critical parameters governing their formation and characteristics

Abstract

The aim of this work was to investigate the feasibility of cross-linker free polyelectrolyte 1 complex formation at the nanoscale between carrageenan (CAR) and protamine (PROT). 2 The properties of CAR/PROT nanoparticles (NPs) were dependent on the carrageenan type: 3 kappa (KC), iota (IC) and lambda (LC), concentration of components, addition of divalent 4 cations, weight mixing ratio (WMR) of constituents and mode of component addition. In the 5 case of 0.1% w/v solutions, IC-based NPs had the smallest particle sizes (100-150 nm) and 6 low polydispersity indices (0.1-0.4). A decrease in the solution concentration from 0.1% to 7 0.05% w/v enabled the formation of KC/PROT NPs. All carrageenans exhibited the ability to 8 form NPs with surface charge ranging from -190 to 40 mV. The inclusion of divalent cations 9 caused an increase in the particle size and zeta potential. Infrared analysis confirmed the 10 presence of a complex between CAR and PROT and showed that IC chains undergo 11 structural changes when forming NPs. Colloidal stability of NPs was related to the initial 12 surface charge of particles and was time-and pH-dependent. IC was found to be the most 13 suitable type of CAR when forming nanoplexes with PROT. 14 15

Optimisation of the self-assembly process: production of stable, alginate-based polyelectrolyte nanocomplexes with protamine

“…Our previous study demonstrated that PROT is able to complex to carrageenans (CARs) forming PECs with properties dependent on the type of carrageen used and its concentration (Dul et al 2015). The complex formation between CAR and PROT was corroborated by infrared analysis and, in the case of iota carrageenan, the polymer chains underwent structural changes when forming NPs.…”

“…The mean particle size (hydrodynamic particle diameter), polydispersity index (PdI) and zeta potential (ZP) values of the polyelectrolyte complexes were determined at 25 ºC by dynamic light scattering (DLS) and laser Doppler velocimetry using a Zetasizer Nano ZS instrumnt (Malvern Instruments Ltd., UK) as described previously (Dul et al, 2015). The results are given as average values of triplicate measurements ± SD.…”

“…Gel Permeation Chromatography (GPC) measurements of the molecular weight of alginates were performed using a HPLC system as described previously (Dul et al 2015). The separative column used was a Plaquagel-OH mixed 8 µm, 300 × 7.5 mm column (Polymer Laboratories Ltd., UK).…”

“…Fourier transform infrared spectroscopy (FTIR) of alginate and PROT was carried out as described previously (Umerska et al 2012;Dul et al 2015).…”

“…To achieve this goal, the alginate/PROT PEC manufacturing process was comprehensively studied including examination of the molecular weight of alginate, the component mixing ratios as well as the sequence of addition and speed of mixing of the constituents guided by the outcomes of previous studies (Dul et al 2015). As one of the most important parameters determining pharmaceutical suitability of a nanoparticle is its colloidal stability, the physical stability of the nanoparticulate dispersions on storage at room temperature and upon the exposure to environments with varying pH was also examined.…”