PDMS microfludic device for optical detection of protein immunoassay using gold nanoparticles

Abstract

A simple but highly specific immunoassay system for goat anti-human IgG has been developed using gold nanoparticles and microfluidic techniques. The assay is based on the deposition of gold nanoparticles that are coated with protein antigens in the presence of their corresponding antibodies to microfluidic channel surface. The effects of time accumulation, the flow velocity, and the concentration of antibodies to the red light absorption percentage (RAP) of deposition were investigated with an ordinary optical microscope. By controlling the reaction time and flow velocity, a dynamic range of 3 orders of magnitude and a detection sensitivity of 10 ng ml(-1) of goat anti-human IgG were achieved. Because of its simplicity and flexibility, this new technique should be useful for fast, highthroughput screening of antibodies in clinical diagnostic applications.

A fast cell loading and high‐throughput microfluidic system for long‐term cell culture in zero‐flow environments

“…After the yeast cells of 10 7 cells/mL were loaded into microtriangle-cavities of seven parallel channels, the culture media containing CuSO 4 of different concentrations were supplied from seven independent inlets. With a programmed x-y moving stage, a CCD scanned the entire chip to read out the cell number in each cavity every 10 min and the fluorescent information after cells had been cultured for 20 h. Supposing the EGFP expression of the yeast cell is in proportion to its fluorescent intensity, ImageJ software (Luo et al, 2005) Fig. 4a and the inset).…”

“…After the cured PDMS was peeled off from the silicon master mold, holes were punched in the PDMS chip with metal pipes for inlet and outlet connections. Finally, the PDMS was bonded to the glass slide after both of them were treated in oxygen plasma for 1 min (Luo et al, 2005). The sterilization of devices was done by first injecting 75% ethanol for 1 h and then exposing it to UV light over night before use.…”

Optical protein sensor for detecting cancer markers in saliva

“…At low target concentrations, surface immobilization (Britland et al, 1992;Mooney, Hunt et al 1996;Lahiri et al, 1999;MacBeath and Schreiber, 2000) is an efficient detection principle, especially when the surface-to-volume ratio is increased (Khandurina and Guttman, 2002;Luo et al, 2005). In this work, we examine the effects of eliminating the enzymatic signal amplification and instead, directly labeling the immobilized proteins with fluorescent probes (Espina et al, 2004;Bashir 2004).…”

Biosensors: The advanced molecular probes - A meta-analysis over a decade

“…[1,2] This malady has been an enigma not only to the patient but also the professional (oral surgeon and oncologist) because cancer is not a disease of a patient alone, but an entire family (physically, psychologically, and socioeconomically). [3][4][5][6] Presently, cancers are being diagnosed very late usually at the untreatable stages, thereby increasing the morbidity and mortality rates and bringing down the survival rate drastically. [3,4,7,8] Hence, in the present scenario, an onus for early diagnosis probably at the molecular or biomolecular level before the genotypic conversion takes place, lays the preamble for combating this deadly disease.…”

“…It has claimed a sensitivity and specificity of 100%. [1,4,6,7] Hence, the present study aims to evaluate the literature for various investigative procedures, to compare their efficacy (dependent on P values) in terms of specificity and sensitivity index, through a meta-analysis with those of biosensors, thus evaluating whether "Biosensors" are indeed a new wave in early stage cancer diagnostics, which could definitely herald a new era in the field of oral oncology diagnosis and treatment planning. [12][13][14] …”