Immunoassay on Free-Standing Electrospun Membranes

Abstract

For the purpose of immunoassay, electrospun membranes can be thought as the threadlike self-assembling of nano/microbeads. Nonwoven membranes of electrospun poly(epsilon-caprolactone) (PCL) fibers display excellent tenacity, flexibility and suitable surface energy. These PCL membranes exhibit easy handling in air, fast spreading, and wetting in aqueous solution, and rapid adsorption of protein molecules by hydrophobic interaction. After a fold-and-press process, the membrane porosity was reduced from approximately 75% to less than 10%, whereas the thickness increased from 5.3 to 280 microm. The resulting fluorescence signal from adsorbed protein increased>120x. With anti-HSA and HSA-FITC as an immunoassay model, a linear detection range from 500 ng/mL down to 1 ng/mL is obtained, with a detection of limit (LOD) of approximately 0.08 ng/mL. By comparison, conventional nitrocellulose and a 24.3 microm PCL fiber electrospun membrane displayed a much higher LOD of approximately 100 ng/mL. Immunoassay on free-standing electrospun membrane successfully combines the low-cost and simplicity of conventional membrane immunoassay, with the fast reaction speed and high sensitivity characteristic of magnetic nano/microbeads bioassays.

Application of a biotin functionalized QD assay for determining available binding sites on electrospun nanofiber membrane

“…Avidin was covalently attached to the carboxylated PVC using 1-ethyl-3-(3-Dimethylaminopropyl) carbodiimide Hydrochloride (EDC) in the presences of N-Hydroxysulfo-succinimide (Sulfo-NHS) (Thermo Fisher Scientific, Rockford, IL) with some modification [7]. Each of the 0.75 cm fibers were placed in individual wells of a 24 well tissue culture plate and wetted with 1 ml phosphate bufferend saline (PBS)/Tween 20 0.3% pH 7.2, soaked for 5 min and then rinsed with 500 ul of pH 5.0, 0.1 M 2-[N-morpholino] ethane sulfonic acid (MES)/0.1% Tween 20, 5 min shaking at 75 rpm on an orbital shaker.…”

“…The origin of the randomness for which the electrospun nanofiber mat is known has been described as a chaotic oscillation of the spinning jet [5] and as a jet whipping and bending instability at the nozzle tip [6]. Research has been conducted on using electrospun membranes as sensors and as substrates for immunoassays [7-12]. Recently, electrospun nanofiber membranes have been demonstrated as a promising technology for biological agent capture and detection [12].…”

Rapid multiplex microfiber-based immunoassay for anti-MERS-CoV antibody detection

“…The environmental and processing conditions were set as noted in Supplementary Material Table S1. After electrospinning, a 'wet-press' technique reported by Wu et al was applied to the microfibers [39]. This technique layered ESPS fiber mats by stacking 8 layers of fibers atop one another, soaking them in ethanol (EtOH) then sandwiching the stack between glass sheets and pressed by a 2 kg weight for 24 h before use.…”

Heat shock proteins as biomarkers for the rapid detection of brain and spinal cord ischemia: a review and comparison to other methods of detection in thoracic aneurysm repair

“…This technology is highly sensitive due to the amplification but requires 2 to 3 h for measurement, although the authors claim a "potential for a real-time detection system" (Munge et al 2010) with further development. Wu et al (2010) developed an electrospun membrane (micro/n polymer fibers from viscous or melted polymers sprayed onto membranes or scaffolds) immunoassay with a linear detection range to 1 ng/ml for human serum albumin (HSA) and HSA-FITC and a fast reaction speed. Signal amplification is currently by a "press and fold" method, and the assay requires 50 min.…”