Synthetic vs Natural: Diatoms Bioderived Porous Materials for the Next Generation of Healthcare Nanodevices

Abstract

Nanostructured porous materials promise a next generation of innovative devices for healthcare and biomedical applications. The fabrication of such materials generally requires complex synthesis procedures, not always available in laboratories or sustainable in industries, and has adverse environmental impact. Nanosized porous materials can also be obtained from natural resources, which are an attractive alternative approach to man-made fabrication. Biogenic nanoporous silica from diatoms, and diatomaceous earths, constitutes largely available, low-cost reservoir of mesoporous nanodevices that can be engineered for theranostic applications, ranging from subcellular imaging to drug delivery. In this progress report, main experiences on nature-derived nanoparticles with healthcare and biomedical functionalities are reviewed and critically analyzed in search of a new collection of biocompatible porous nanomaterials.

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

“…During their reproduction cycle, once diatoms reach their maximum size, progeny cells are generated by mitosis of the parent cells with production of new frustules with unchanged morphology, since each parent's valve acts as the epivalve of the new growing frustule: this mechanism ensures high reproducibility of shape, size, and nanostructure of the biosilica shells. Hence, diatoms can be regarded as easily growing microscopic biofactories, whose massive and low‐cost cultures can be envisaged on a large scale, with an estimated algal productivity of about 70 × 10 6 tons ha −1 year −1 in open ponds and about 150 × 10 6 tons ha −1 year −1 in photo‐bioreactors . These cultures can provide biosilica shells with much higher structural monodispersity than that of fossil diatoms (diatomaceous earth (DE)) commonly used in a raw form as abrasive or filtering materials, biofertilizers, and food integrators.…”

“…The major applications of diatom biosilica shells as mesoporous materials for biosensing, diagnostics, and drug delivery have been recently reviewed by Dolatabadi and de la Guardia and Rea et al Review articles have also highlighted the potential of diatoms' nano‐biotechnology for applications in energy conversion and storage, photovoltaics, and optoelectronics …”

Diatom Silica for Biomedical Applications: Recent Progress and Advances

“…Diatom frustules also inspired the design and production of novel nanostructured materials due to their unique 3D porous pill‐box biologically derived structures, which could be suitable for movement in biological environment. Their hollow porous microcapsule structure render them ideal for the development of nano‐/microdrug carriers for a variety of medical therapies including theranostics and microrobotics . The hollow and porous structure of DE silica offers large surface area that enables high loading capacity and the porous structure maintains the therapeutic drug in amorphous form that is crucial for enhancing the solubility and increasing the permeability of lipophilic drugs, as reported in a number of studies from our group and others …”

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

“…made on the surface to fabricate therapeutic diatom-based reservoirs as previously noted. [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.…”