Biomolecular detection, tracking, and manipulation using a magnetic nanoparticle-quantum dot platform

Kalpesh D. Mahajan, Gang Ruan, Greg Vieira, Thomas Porter, Jeffrey J. Chalmers, R. Sooryakumar, Jessica O. Winter*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Fluorescent and magnetic materials play a significant role in biosensor technology, enabling sensitive quantification and separations with applications in diagnostics, purification, quality control, and therapeutics. Here, we present a magneto-fluorescent biosensor/separations platform consisting of quantum dots (QDs) and superparamagnetic iron oxide nanoparticles (SPIONs) that are separately encapsulated in amphiphilic block co-polymer micelles conjugated to DNA or protein (i.e., single-stranded (ss) DNA derived from the mRNA of the tumor suppressor protein p53 or avidin protein). Analytes were detectedviaan aggregation sandwich assay upon binding of at least 1 QD and 1 SPION-containing micelle to result in a fluorescent/magnetic composite. Multiplexed isolation of protein and DNA biomolecules was demonstrated by using QDs of varying emission wavelength; QD fluorescence intensity could be correlated with analyte concentration. Sequential or parallel biomolecule separation was achieved by adding appropriately functionalized SPION-containing micelles and applying user-controlled magnetic fieldsviapatterned magnetic disks and wires. QD fluorescence was used to continuously visualize analyte separation during this process. This QD/SPION platform is simple to use, demonstrates ~10-16M sensitivity in analyte detection (comparable to competing QD biosensors based on energy transfer) with specificity against 1 and 2 basepair mismatches in DNA detection, molecular separations capability in solutions of ~10-10M, and permits simultaneous or parallel, multiplexed separation of protein and DNA. Thus, this versatile platform enables self-assembly-based rapid, sensitive, and specific detection and separation of biomolecules, simultaneously and with real-time visualization. This technology demonstrates potential for nanoscale assembly, biosensing, and bioseparations.

Original languageEnglish
Pages (from-to)3534-3541
Number of pages8
JournalJournal of Materials Chemistry B
Issue number16
Publication statusPublished - 28 Apr 2020
Externally publishedYes

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