posted on 2021-11-18, 22:29authored byGiulia Santopolo, Antonio Clemente, Maria Aranda, Antonia Socias, Alberto del Castillo, Aniceta Chica, Marcio Borges, Roberto de la Rica
Hyperdegranulation
of neutrophilic granulocytes is a common finding
in sepsis that directly contributes to the heightened immune response
leading to organ dysfunction. Currently, cell degranulation is detected
by flow cytometry, which requires large infrastructure that is not
always available at the point of care. Here, we propose a plasmonic
assay for detecting the degranulation status of septic cells colorimetrically.
It is based on triggering the aggregation of gold nanoparticles with
cationic granule proteins. Cells from septic patients contain fewer
granules and therefore release less cationic proteins than healthy
cells. This results in red-colored assays than can be easily detected
by eye. The assay can selectively detect cationic granule proteins
even in the presence of an excess of unrelated proteins, which is
key to detect degranulation with high specificity. Coupling this signal
generation mechanism with a magnetic purification step enabled the
identification of septic cells with the same performance as flow cytometry.
This makes the proposed method a promising alternative for diagnosing
sepsis in decentralized healthcare schemes.