Thymidine kinase
1 (TK1) is traditionally a serum biomarker that
is elevated in the early stages of malignancies. The diagnostic and
prognostic role of TK1 for screening and monitoring human malignancies
has recently been investigated. Anti-human TK1 aptamers were selected
through 12 iterative rounds of systematic evolution of ligands by
exponential enrichment from a DNA library. The aptamer pool of round
12 was amplified, and the polymerase chain reaction product was cloned
on the TA vector. Of the 85 colonies obtained, 52 were identified
as positive clones. These aptamers were screened for TK1 with surface
plasmon resonance, where apta37 and apta69 showed the highest affinity
for TK1. The TK1_apta37 and TK1_apta69 aptamers were used in a sandwich
assay platform and successfully detected TK1 in the concentration
range of 54–3500 pg mL–1. Clinical samples
from 60 cancerous patients were also tested with this assay system
and compared using the conventional antibody-based enzyme-linked immunosorbent
assay kit. The aptamer sandwich assay demonstrated a dynamic range
for TK1 at clinically relevant serum levels, covering subpicogram
per milliliter concentrations. The new approach offers a simple and
robust method for detecting serum biomarkers that have low and moderate
abundance. The results of this study demonstrate the screening capability
of the aptamer sandwich assay platform and its potential applicability
to the point-of-care testing system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.