title: A PMMA microcapillary quantum dot linked immunosorbent assay (QLISA).
abstract: The development of a simple and inexpensive quantum dot based immunoassay for detecting myeloperoxidase (MPO) in stool samples is reported (QLISA). The method developed utilizes readily available polymethylmethacrylate (PMMA) microcapillaries as substrates for performing the sandwich assay. High power (80 mW) and low power (10 mW) UV-LEDs were tested for their efficiency in maximizing detection sensitivity in a waveguide illumination or a side illumination mode. The results obtained indicate that both waveguide and side illumination modes can be employed for detecting MPO down to 15 ng/mL, however the high power LED in a side illumination mode improves sensitivity and simplifies the data acquisition process. The protocol and sensor robustness was evaluated with animal stool samples spiked with MPO and the results indicate that the sensitivity of detection is not compromised when used in stool samples. The effect of the ionic strength of the environment on the fluorescence stability of quantum dots was evaluated and found to affect the assay only if long imaging times are employed. Replacing the buffer with glycerol during imaging increased the fluorescence intensity of quantum dots while significantly minimized the loss in intensity even after 2h.
authors.affiliation: School of Biomedical Engineering Science & Health Systems, Drexel University, Philadelphia, PA 19104, USA.
authors.forename: Sundar
authors.initials: S
authors.lastname: Babu
authors.forename: Sakya
authors.initials: S
authors.lastname: Mohapatra
authors.forename: Leonid
authors.initials: L
authors.lastname: Zubkov
authors.forename: Sreekant
authors.initials: S
authors.lastname: Murthy
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Papazoglou
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation*; D002197:Capillary Action; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005243:Feces / Q000737:chemistry*; D008904:Miniaturization; D009195:Peroxidase / Q000032:analysis*; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D045663:Quantum Dots; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*
chemical_list: D019904:Polymethyl Methacrylate; D009195:Peroxidase