title: Detection of cancer cells using a peptide nanotube-folic acid modified graphene electrode.
abstract: This article describes the preparation of a graphene electrode modified with a new conjugate of peptide nanotubes and folic acid for the selective detection of human cervical cancer cells over-expressing folate receptors. The functionalization of peptide nanotubes with folic acid was confirmed by fluorescence microscopy and atomic force microscopy. The peptide nanotube-folic acid modified graphene electrode was characterized by scanning electron microscopy and cyclic voltammetry. The modification of the graphene electrode with peptide nanotube-folic acid led to an increase in the current signal. The human cervical cancer cells were bound to the modified electrode through the folic acid-folate receptor interaction. Cyclic voltammograms in the presence of [Fe(CN)(6)](3-/4-) as a redox species demonstrated that the binding of the folate receptor from human cervical cancer cells to the peptide nanotube-folic acid modified electrode lowered the electron transfer resulting in a decrease in the measured current. A detection limit of 250 human cervical cancer cells per mL was obtained. Control experiments confirmed that the peptide nanotube-folic acid electrode specifically recognized folate receptors. The modified electrode described here opens up new possibilities for future applications in early stage diagnoses of diseases where cells over-express folate receptors, such as in cancer or leishmaniasis disease.
authors.affiliation: Centro de Investigaciones en Catálisis, Universidad Industrial de Santander, Sede Guatiguará UIS Km 2 vía Refugio, Piedecuesta, Colombia.
authors.forename: John J
authors.initials: JJ
authors.lastname: Castillo
authors.forename: Winnie E
authors.initials: WE
authors.lastname: Svendsen
authors.forename: Noemi
authors.initials: N
authors.lastname: Rozlosnik
authors.forename: Patricia
authors.initials: P
authors.lastname: Escobar
authors.forename: Fernando
authors.initials: F
authors.lastname: Martínez
authors.forename: Jaime
authors.initials: J
authors.lastname: Castillo-León
mesh_terms: D004566:Electrodes; D005260:Female; D005492:Folic Acid / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D045333:Nanotubes, Peptide / Q000737:chemistry*; D002583:Uterine Cervical Neoplasms / Q000737:chemistry* / Q000175:diagnosis
chemical_list: D045333:Nanotubes, Peptide; D006108:Graphite; D005492:Folic Acid