Improving the In Vitro Removal of Indoxyl Sulfate and p-Cresyl Sulfate by Coating Diatomaceous Earth with Polydopamine

• Published in: Toxins 2022-12, Vol.14 (12)
• Main Authors: Cicco, Stefania Roberta, Giangregorio, Maria Michela, Rocchetti, Maria Teresa, di Bari, Ighli, Mastropaolo, Claudio, Labarile, Rossella, Ragni, Roberta, Gesualdo, Loreto, Farinola, Gianluca Maria, Vona, Danilo
• Format: Article
• Language: English
• Subjects: Chemical properties; Diatomaceous earth; Dopamine; Health aspects; Microbial toxins; Polymers; Toxicology
• ISSN: 2072-6651; 2072-6651
• DOI: 10.3390/toxins14120864

Polydopamine (PDA) is a synthetic eumelanin polymer mimicking the biopolymer secreted by mussels to attach to surfaces with a high binding strength. It exhibits unique adhesive properties and has recently attracted considerable interest as a multifunctional thin film coating. In this study, we demonstrate that a PDA coating on silica- and polymer-based materials improves the entrapment and retention of uremic toxins produced in specific diseases. The low-cost natural nanotextured fossil diatomaceous earth (DE), an abundant source of mesoporous silica, and polyvinylpyrrolidone-co-Styrene (PVP-co-S), a commercial absorbent comprising polymeric particles, were easily coated with a PDA layer by oxidative polymerization of dopamine at mild basic aqueous conditions. An in-depth chemical-physical investigation of both the resulting PDA-coated materials was performed by SEM, AFM, UV-visible, Raman spectroscopy and spectroscopic ellipsometry. Finally, the obtained hybrid systems were successfully tested for the removal of two uremic toxins (indoxyl sulfate and p-cresyl sulfate) directly from patients’ sera.