Porous silica microshells from diatoms as biocarrier for drug delivery applications

Diatoms: a biotemplating approach to fabricating drug delivery reservoirs

“…Using BET (Brunauer-Emmett-Teller) nitrogen adsorption analysis, the diatom surface area was quantified to be 18.5 ± 0.8 m 2 /g, significantly higher than traditional nano-and micro-scale drug delivery particulate systems [31]. Furthermore, they have also reported drug encapsulation and release of indomethacin (model water-insoluble drug) and gentamicin (model water-soluble drug) on both bare diatom structures [32,33] and diatoms modified with silanes and phosphonic acids to render the surface of the diatom either hydrophilic or hydrophobic, allowing them to investigate the effect of surface functionalization on controlling diffusion rates and drug delivery rates [34][35][36]. The aforementioned experiments observed drug release kinetics in a biphasic manner, with an initial burst release of 6 h (attributed to the surface-deposited drug) followed by near-zero-order sustained release over a prolonged 2-week period of time (attributed to the drug released from the internal hollow structures of the diatom).…”

“…The topographical advantages of the diatom structure are well established and preliminary drug delivery experiments have confirmed favorable release kinetics [31][32][33][34][35][36][37][38]; however, only a single study has looked at the efficacy of diatoms as drug delivery reservoirs in vitro [37]. Furthermore, there is a need to evaluate the efficacy of diatom drug delivery in vivo and a comparison of the delivery route of administration and regulatory path will decide the clinical application and implementation of this novel drug delivery platform.…”

Diatom frustules as a biomaterial: effects of chemical treatment on organic material removal and mechanical properties in cleaned frustules from two Coscinodiscus species

“…The three-dimensional nanoporous structure of diatom frustules consists mainly of silica nanoparticles, and the architecturewith layers and different sized pores -gives rise to several interesting material applications, e.g. nano-to micrometer scaled sieves [5] or drug carriers [6] , [7] as well as vectors for drug delivery [8] , protein adsorbents [9] and as photocatalysts [10] . Diatom frustules also show particular optical properties [11] , [12] , [13] , [14] , [15] , [16] , [17] making them interesting for several optical applications [18] .…”

Targeted drug delivery using genetically engineered diatom biosilica

“…Diatom biosilica exhibits both high surface area (B100 m 2 g À 1 ) 6 and high mechanical stability 7 . Losic and colleagues 8,9 have pursued the idea of using diatom biosilica as a biocarrier for applications in oral and implant drug delivery, and have demonstrated their potential to replace synthetic silica-based materials. Chemical functionalization allows for the tailoring of drug binding and release properties 10,11 , and for the covalent immobilization of functional antibody molecules to diatom silica 12,13 .…”