Linear Polymers Versus PAMAM Dendrimers In The Interaction With Transmembrane Ocular Mucins: Analysis By Biosensor Technology

Abstract

Purpose: : To compare the chemical interaction between ocular transmembrane mucins and linear polymers and PAMAM dendrimers using surface plasmon resonance (SPR).

Methods: : Ocular surface mucins were obtained from stratified cultures of human corneal epithelial (HCLE) cells and purified using size-exclussion chromatogaphy followed by isopycnic density gradient centrifugation. Solutions of linear polymers; hyaluronic acid [HA], carboxymethyl cellulose [CMC], hydroxypropylmethyl cellulose [HPMC], chitosan [Ch] and also PAMAM dendrimers containing -NH2, -OH and -COOH terminal groups were probed with a sensor chip surface, where transmembrane ocular mucins were previously immobilized, for 300s at 10 µl/min. Afterwards, the sensorgram was collected until equilibrium was reached. All studies were performed in triplicate at 35ºC. Concentrations of HA (0.2%), CMC (0.5%, HPMC (0.3%) were chosen among the ones employed in artificial tears.

Results: : As determined by western blot using the M11 antibody against MUC16, purified samples from HCLE cells consisted of mucin with a buoyant density range of 1.26 to 1.44 g/ml. Concerning mucoadhesion properties, among the linear polymers evaluated, only Ch interacted significantly with ocular transmembrane mucins (p G4 PAMAM-NH2 (2%) = G4 PAMAM-OH (2%) > G3.5 PAMAM-COOH (2%) >>> CMC (0.5%) = HA (0.2%) = HPMC (0.3%).

Conclusions: : Anionic and non-ionic linear polymers can interact with transmembrane ocular mucins thorough an interpenetration phenomenon. However, chitosan and PAMAM dendrimers establish permanent interactions with mucins, supporting their use in enhancing drug retention time at the ocular surface and hence, bioavailability.

Keywords: cornea: surface mucins