title: A rapid, direct, quantitative, and label-free detector of cardiac biomarker troponin T using near-infrared fluorescent single-walled carbon nanotube sensors.
abstract: Patients with chest pain account for 10% of US emergency room visits according to data from the Center for Disease Control and Prevention (2013). For triage of these patients, cardiac biomarkers troponin I and T are endorsed as standard indicators for acute myocardial infarction (AMI, or heart attack). Thus, there is significant interest in developing a rapid, point-of-care (POC) device for troponin detection. In this work, a rapid, quantitative, and label-free assay, which is specific for cardiac troponin T (cTnT) detection, using fluorescent single-walled carbon nanotubes (SWCNTs), is demonstrated. Chitosan-wrapped carbon nanotubes are cross-linked to form a thin gel that is further functionalized with nitrilotriacetic acid (NTA) moieties. Upon chelation of Ni(2+) , the Ni(2+) -NTA group binds to a hexa-histidine-modified troponin antibody, which specifically recognizes the target protein, troponin T. As the troponin T binds to the antibody, the local environment of the sensor changes, allowing direct troponin detection through intensity changes in SWCNT bandgap fluorescence. This platform represents the first near-infrared SWCNT sensor array for cTnT detection. Detection can be completed within 5 min, demonstrating a linear response to cTnT concentration and an experimental detection limit of 100 ng mL(-1) (2.5 nm). This platform provides a promising new tool for POC AMI detection in the future. Moreover, the work presents two new methods of quantifying the number of amines and carboxylic groups, respectively, in a carbon hydrogel matrices.
authors: Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
authors: Jingqing
authors: J
authors: Zhang
authors: Sebastian
authors: S
authors: Kruss
authors: Andrew J
authors: AJ
authors: Hilmer
authors: Steven
authors: S
authors: Shimizu
authors: Zeke
authors: Z
authors: Schmois
authors: Flor
authors: F
authors: De La Cruz
authors: Paul W
authors: PW
authors: Barone
authors: Nigel F
authors: NF
authors: Reuel
authors: Daniel A
authors: DA
authors: Heller
authors: Michael S
authors: MS
authors: Strano
mesh_terms: D015415:Biomarkers / Q000097:blood*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D048271:Chitosan / Q000737:chemistry; D006801:Humans; D018625:Microscopy, Atomic Force; D009203:Myocardial Infarction / Q000175:diagnosis*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D037742:Nanotubes, Carbon; D020107:Troponin T; D048271:Chitosan
keywords: carbon nanotubes; cardiac biomarkers; fluorescence; near-infrared; troponin