Introduction: Liquid biopsy is an emerging and promising technique that enables the detection of molecular biomarkers in various body fluids, such as blood, urine, and saliva. Although conventional tissue biopsy remains the gold standard for tumor diagnosis, liquid biopsy offers several advantages, including its minimally invasive nature and its ability to provide valuable information for diagnosis, prognosis, treatment, and remission monitoring in oncology. The most commonly used marker in liquid biopsy is cell-free DNA (cfDNA), a small DNA fragment carrying information capable of detecting and characterizing cancer fingerprints. However, despite its potential, cfDNA analysis presents challenges. Its low concentration and susceptibility to contamination by genomic DNA (gDNA) require specialized extraction techniques. Nanotechnology emerges as a promising strategy to overcome these limitations. Magnetic iron oxide nanoparticles, such as magnetite (Fe3O4) and maghemite (γ-Fe2O3), were functionalized with a silica (SiO2) coating to selectively interact with cfDNA fragments in biological samples. Thus, the main goal of this study was to synthesize magnetic nanoparticles with optimized size, surface area, and coating to extract and purify cfDNA from peripheral blood samples. Methodology: Magnetite and maghemite nanoparticles were synthesized via co-precipitation, functionalized with silica (SiO2), characterized, and their performance was compared with commercial magnetic beads for cfDNA extraction. Results: cfDNA extraction from peripheral blood was achieved, revealing performance differences between magnetite and maghemite nanoparticles. Conclusions: Silica-coated iron oxide magnetic nanoparticles proved to be a promising tool, achieving comparable performance to commercial kits for cfDNA extraction and purification.
Author Contributions
Conceptualization, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; methodology, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; software, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; validation, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; formal analysis, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; investigation, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; resources, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; data curation, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; writing—original draft preparation, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; writing—review and editing, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; visualization, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; supervision, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; project administration, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S.; funding acquisition, D.S.R., Y.R.C.L.A., J.A.C. and F.P.-S. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—88887.207440/2025-00.
Institutional Review Board Statement
The study was conducted in accordance with the Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) of Institutional Ethics Committee (CAAE number 65822222.4.0000.0030).
Informed Consent Statement
Informed consent was obtained from all subjects involved in the study.
Data Availability Statement
The data presented in this study are available upon request from the corresponding author.
Conflicts of Interest
The authors declare no conflict of interest.
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