title: Exploration of the biomacromolecular interactions of an interpenetrating proteo-saccharide hydrogel network at the mucosal interface.
abstract: The relationship between mucin (MUC) and pectin (PEC) was explored in an attempt to understand the biomacromolecular interactions that occur at mucosal surfaces when mucus membranes are exposed to PEC-based materials. These interactions were explored through techniques, such as attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, SEM imagery of lyophilized MUC-PEC blends, thermodynamic analysis, rheology investigations, and in silico static lattice atomistic simulations using a molecular mechanics energy relationships (MMER) approach. Three types of PEC that had different degrees of esterification and degrees of amidation were investigated at different MUC-PEC mass ratios (1:0, 1:1, 1:4, 1:9, and 0:1). The effect PEG 400 and Ca(2 +) in the MUC-PEC interactions were also studied. ATR-FTIR spectroscopy revealed broadening and strengthening of FTIR peaks at 3363 cm(-1) and between 3000-3650 cm(-1) due to stretching vibrations of the -OH, -COOH groups on MUC and PEC as well as the -N-H group on MUC. This suggested significant intra- and inter-molecular H-bonding. Morphologically, MUC-rich scaffolds were porous, thin, and multidirectional compared with the smooth, rigid, and unidirectional PEC-rich scaffolds. The Flory-Huggins interaction parameter (χ12 ) for all MUC-PEC mass ratios was negative, thus confirming MUC-PEC miscibility and interactions. UV absorbance increased with increasing relative concentration of PEC in the aqueous MUC-PEC dispersions. Furthermore, rheology investigations demonstrated synergistic enhancement in viscosity (η) and dynamic moduli upon the addition of PEG 400 and Ca(2 +) . MMER analysis revealed several key MUC-PEC interactions that corroborated well with the experimental data. Notably, higher esterification and larger mass ratios of PEC yielded greater MUC-PEC interactions.
authors.affiliation: University of the Witwatersrand, Faculty of Health Sciences, Department of Pharmacy and Pharmacology, 7 York Road, Parktown, 2193, Johannesburg, South Africa.
authors.forename: Felix
authors.initials: F
authors.lastname: Mashingaidze
authors.forename: Yahya E
authors.initials: YE
authors.lastname: Choonara
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
authors.forename: Lisa C
authors.initials: LC
authors.lastname: du Toit
authors.forename: Vinesh
authors.initials: V
authors.lastname: Maharaj
authors.forename: Eckhart
authors.initials: E
authors.lastname: Buchmann
authors.forename: Valence M K
authors.initials: VM
authors.lastname: Ndesendo
authors.forename: Viness
authors.initials: V
authors.lastname: Pillay
mesh_terms: D000818:Animals; D002152:Calorimetry, Differential Scanning; D002241:Carbohydrates / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D055119:Elastic Modulus; D005612:Freeze Drying; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000378:metabolism*; D046911:Macromolecular Substances; D009077:Mucins / Q000378:metabolism*; D009092:Mucous Membrane / Q000378:metabolism*; D010368:Pectins / Q000378:metabolism*; D012212:Rheology; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D034421:Sus scrofa; D013816:Thermodynamics; D014783:Viscosity
chemical_list: D002241:Carbohydrates; D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D009077:Mucins; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D010368:Pectins
keywords: Mucin; macromolecular interaction; molecular mechanics energy relationships; pectin; synergistic enhancement in rheology