Surface-functionalized diatom microcapsules for drug delivery of water-insoluble drugs

dc.contributor.authorAw, M.
dc.contributor.authorBariana, M.
dc.contributor.authorYu, Y.
dc.contributor.authorAddai-Mensah, J.
dc.contributor.authorLosic, D.
dc.date.issued2013
dc.description.abstractNaturally available and biocompatible materials are potential substitutes for synthetic mesoporous materials as suitable drug carriers for the development of cost-effective drug delivery systems. This work investigates the application of a porous silica material derived from diatoms, also known as diatomaceous earth. The aim is to explore the surface functionalization of diatom microcapsules and their impact on the drug loading and release characteristics of water-insoluble drugs. Indomethacin was used as the model for poorly soluble drug. The surface modification on diatoms was performed with two organosilanes; 3-aminopropyltriethoxy silane and N-(3-(trimethoxysilyl) propyl) ethylene diamine and phosphonic acids (2-carboxyethyl-phosphonic acid and 16-phosphono-hexadecanoic acid) providing organic surface hydrophilic and hydrophobic properties. Extensive characterizations using scanning electron microscopy, X-ray photoelectron spectroscopy and differential scanning calorimetry was performed to confirm covalent grafting of monolayer aminosilane and phosphonic acid on the diatom surfaces. Differences in loading capacity of diatoms (15–24%) and release time (6–15 days) were observed which is due to the presence of different functional groups on the surface. It was found that 2-carboxyethyl-phosphonic acid, 3-aminopropyltriethoxy silane and N-(3-(trimethoxysilyl) propyl) ethylene diamine render diatom surfaces hydrophilic, due to polar carboxyl functional group (COOH) and active amine species (NH and NH2) that favor drug adsorption; better encapsulation efficiency and prolonged release of drugs, over the hydrophobic surface created by 16-phosphono-hexadecanoic acid. This work demonstrates diatom porous silica as a promising drug carrier, with possibility to further improve their performances by tailoring their surface functionalities to achieve the required drug loading and release characteristics for different therapeutic conditions.
dc.description.statementofresponsibilityMoom Sinn Aw, Manpreet Bariana, Yang Yu, Jonas Addai-Mensah and Dusan Losic
dc.identifier.citationJournal of Biomaterials Applications, 2013; 28(2):163-174
dc.identifier.doi10.1177/0885328212441846
dc.identifier.issn0885-3282
dc.identifier.issn1530-8022
dc.identifier.orcidLosic, D. [0000-0002-1930-072X]
dc.identifier.urihttp://hdl.handle.net/2440/76207
dc.language.isoen
dc.publisherTechnomic Publishing Company
dc.relation.granthttp://purl.org/au-research/grants/arc/LP0989229
dc.rights© The Author(s) 2012
dc.source.urihttps://doi.org/10.1177/0885328212441846
dc.subjectDrug delivery
dc.subjectdiatoms
dc.subjectdiatomaceous earth
dc.subjectsurface modifications
dc.subjectsilanes
dc.subjectphosphonic acid
dc.subjectindomethacin
dc.titleSurface-functionalized diatom microcapsules for drug delivery of water-insoluble drugs
dc.typeJournal article
pubs.publication-statusPublished

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