Folate-binding protein self-aggregation drives agglomeration of folic acid targeted iron oxide nanoparticles

Junjie Chen, Sarah Klem, Alexis K. Jones, Bradford Orr, Mark M. Banaszak Holl

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)


Folate-conjugated nanomaterials have been widely investigated for drug and imaging-agent delivery. In this work, two folic acid (FA) conjugated iron oxide particles (IOP), a ∼40 nm diameter FA-IOP and a ∼450 nm diameter FA-IOP(FA-SeraMag), were synthesized. Both particles aggregated in the presence of serum folate-binding protein (FBP) at physiological concentration and buffer conditions. Mixing 0.01% w/w FA-conjugated iron oxide particles with FBP-induced agglomeration generated an average hydro-dynamic particle diameter of 3800 ± 1100 nm for ∼40 nm FA-IOP and 4030 ± 1100 nm for FA-SeraMag as measured by dynamic light scattering (DLS). The presence of excess human serum albumin (HSA) (600 μM) did not prevent agglomeration of the ∼40 nm FA-IOP; however, it did inhibit agglomeration of FA-SeraMag. Atomic force microscopy measurement provided additional insight into particle morphology with the detection of individual particles in the agglomerate. This behavior is an example of a triggered cascade. A protein structural change is induced by FA binding, and the structural change favors aggregation of the ∼4 nm diameter FBPs on the particle surface; this further triggers the agglomeration of both the ∼40 and ∼450 nm diameter IOPs.

Original languageEnglish
Pages (from-to)81-87
Number of pages7
JournalBioconjugate Chemistry
Issue number1
Publication statusPublished - 1 Jan 2017
Externally publishedYes

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