Here,
we report the green synthesis of silica-based materials for
the treatment of biological samples such as bacteria enrichment and
exosome isolation. The synthesized materials were nanosized, recyclable,
and magnetically separable using an eco-friendly hydrothermal synthesis
approach. Fe3O4 formation on the surface of
biosilica porous diatomite via precipitation was used to create a
magnetic diatom (mag-DE) through a bottom-up approach, which was low
cost, robust, nontoxic, and eco-friendly. Following the addition of l-arginine-containing amino groups, the mag-DE showed broad
absorbance in the visible light spectrum (UV–vis), and the
amine functional groups of 3-aminopropyl triethoxysilane on the DE
via the amidine bond were confirmed using Fourier transform infrared
analysis. Further studies were conducted by conjugating the mag-DE
with concanavalin A (ConA), a known micro-antimicrobial agent for
bacterial enrichment, as well as with a specific antibody for exosome
isolation. The large-volume samples obtained were easy to use, and
the materials could enrich a minimum of 50 colony-forming units (CFUs)
of Salmonella and also showed a promising ability
to capture another bacterial species. In addition, the modified synthetic
mag-DE could be used for exosome isolation using affinity purification.
Functionalized mag-DE could be magnetically isolated in a rapid and
more efficient manner than using the conventional method, which can
be altered for exosome isolation in research and clinical applications.
This study presents the unique physical and chemical properties of
green synthesized mag-DE, whose surface can be easily modified. Thus,
it creates a novel potential strategy for several desirable applications
for various types of biological samples.