Natural nanoporous silica frustules from marine diatom as a biocarrier for drug delivery

Abstract

The possible use of natural silica nanoporous biomaterial from marine diatom for drug delivery applications was explored. Coscinodiscus concinnus have a homogeneous size distribution with radius of 220 ± 15 lm with surface featuring a mounded topography with about 2 lm wide porous domes organized on the surface in pentagonal packing. Streptomycin, used as a hydrophilic drug to demonstrate the in vitro oral drug delivery model based on diatom structure, mainly adsorbed on to the diatom silica surface (foramen), inside pores (cribrum) and into the internal hollow diatom structure (cribellum). The maximum drug loading capacity of streptomycin was 33.33 ± 2 %. The release was biphasic, involving initial burst release (first 6 h) mainly from the surface of diatom foramen, and sustained drug release (upto 7 days) from cribrum and cribellum. The study indicated that the live diatoms from marine environment, due to their unique features (easy cultivable, low-cost and biocompatibility), are a potential and alternative natural source of nanoporous siliceous material for in vitro oral drug delivery applications.

Multiple Routes to Smart Nanostructured Materials from Diatom Microalgae: A Chemical Perspective

“…They are mainly based on treatment with highly concentrated acids (HCl, H 2 SO 4 ) or mixtures of acids and oxidizing agents, such as the piranha water solution of 2M H 2 SO 4 and 10% H 2 O 2 . For example, in the frame of studies of the application of diatom shells in drug delivery, Gnanamoorthy et al treated Coscinodiscus concinnus diatoms cultured in the laboratory with an acid aqueous solution of hydrogen peroxide to clean the frustules, and then loaded them with streptomycin drug on both the external and internal biosilica surfaces, including the pores . A reduction in the pore size was observed after drug loading, indicating the presence of streptomycin molecules physisorbed therein.…”

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] .…”

Therapeutic Applications of Phytoplankton, with an Emphasis on Diatoms and Coccolithophores

“…In vitro --In vitro Oral drug delivery [62] Diatom Coscinodiscus wailesii, [44] Coscinodiscus concinnus Wm.…”

“…[12,60] Some notable examples include direct surface modification of diatoms and diatom-based materials (diatomite) to control the release of both hydrophilic and hydrophobic drugs. [18,[61][62][63] As an illustration, fabrication of stimuli-responsive diatoms using aqueous silica electrontransfer-based atom transfer radical polymerization (Si-ARGET-ATRP) was demonstrated as a controlled hydrophobic drug delivery device. [64] [4][5] MA copolymer is heated (45°C) above its lower critical solution temperature (LCST) and then cooled down (25°C) below its LCST, it behaves as an actuator, transitioning between a rigid (below LCST) and collapsed state (above LCST), thus keeping the drug entrapped (below LCST) or releasing it (above LCST).…”