Diatom Biosilica in Targeted Drug Delivery and Biosensing Applications: Recent Studies

Abstract

Diatoms are single-cell algae encased in a cell wall (named frustule) composed of transparent, biogenic (or opaline) silica with intricate and strikingly regular patterns. Over the past 30 years, these microorganisms have proven to be a valuable replacement for synthetic silica that satisfies numerous pharmaceutical requirements for the realization of drug delivery vectors, biosensing supports and photonic crystals. It is not only the structural features of the diatoms, but also the possibility of chemically modifying the frustule that permits the relatively straightforward transformation of the biosilica into potential devices for biomedical applications. In this short review, we explore the applications of diatoms-derived biosilica in the drug delivery and biosensing fields. Specifically, we consider the use of diatoms for the targeted delivery of anticancer and antibiotic drugs and how the same microalgae are employed in the fabrications of biosensors whose analyte signal response is evaluated via fluorescence and surface-enhanced Raman scattering techniques. We limit our discussion to studies published in the last seven years, with the intention of minimizing possible redundancy with respect to previously published contributions.