Surface Modified Ultrathin Polyelectrolyte Nanoreservoir for Delivery of Proteins: Evaluation in Terms of Controlled Release and Biocompatibility

The proposed ultrathin polyelectrolyte nanoreservoir (UPN) was fabricated in two combinations by alternate layering of polyelectrolytes poly (allylamine hydrochloride) along with sodium poly (styrene sulfonate) (PAH/PSS)5 and sodium alginate (PAH/SA)5 using porous calcium carbonate as a template using layer-by-layer adsorption technique with the subsequent template removal at low pH. We studied the possibility whether remnant intact nanoreservoir could be suited for encapsulation as well as delivery vehicle for protein such as bovine serum albumin as a model. To tune biocompatibility with biological cells the assembled surface was modified using pluronic (F-68) by adsorption and possible hydrophobic interaction. The prepared system was characterized for surface morphology, size and size distribution, surface charge, layer-by-layer growth due to sequential adsorption and surface modification. The experimental data obtained by Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) provide evidence for the stepwise surface modification of the films. Further the system was investigated for payload efficiency of proteins, in-vitro release profile, integrity of proteins, cell adhesion and viability against biological cells (murine macrophages cell line J774.1). In both formulations polyelectrolyte composition lead to smooth and spherical nanomatrix, with payload of approx. 72±6% of proteins. Both the systems exhibited biphasic release profile with initial burst release followed by controlled release with overall release of 43.63±4.8% and 44±5.76% in 48h for formulation prepared by combination of (PAH/PSS)5 and (PAH/SA)5 respectively. There was a marked reduction in cell adhesion and improvement in viability upon surface modification. In a nutshell, the proposed system could successfully be used for the delivery of proteins and moreover the system can be tailored to impart desired properties at any stage of layering especially in terms of drug release and to retain the integrity of proteins.