Anti-IgG-anchored liquid crystal microdroplets for label free detection of IgG

다국어 초록 (Multilingual Abstract)

<P>The orientational variation of 4-cyano-4′-pentyl biphenyl (5CB) molecules in LC microdroplets in response to IgG antigen (IgG) interactions has been utilized to develop a biosensor for rapid and label-free detection of IgG in biological fluids. In order to prepare a LC microdroplet-based biosensor, the anti-IgG (AIgG) anchored 4-cyano-4′-pentyl biphenyl LC microdroplets were prepared in the presence of sodium dodecylsulfate (SDS) as a mediator and amphiphilic poly(styrene-<I>b</I>-acrylic acid) (PS-<I>b</I>-PA) as a modifier of the LC/water interface. The AIgG-anchored LC microdroplets with a size variation from 20 to 30 μm have been used successfully for the detection of IgG within a concentration range of 20 to 1000 ng mL<SUP>−1</SUP>, at a detection limit of as low as 16 ng mL<SUP>−1</SUP>, and a response time of 30 min in PBS solution at room temperature. The LC microdroplets anchored with 5 μg mL<SUP>−1</SUP> of AIgG were found to be more sensitive for the detection of IgG in the concentration range from 20 to 800 ng mL<SUP>−1</SUP> in PBS. The AIgG-anchored LC microdroplets have shown a delayed response of 90 minutes for IgG in a solution containing 10% FBS or 10% blood plasma in comparison to PBS solution. The LC microdroplets anchored with 5 μg mL<SUP>−1</SUP> (34 pmol) of AIgG have shown a recovery of 106% of IgG, a coefficient of variance of ±4% and a precision within a limit of 1-6% for a spiked sample of 25 ng mL<SUP>−1</SUP> of IgG. The results indicated that orientational response of LC microdroplets is potentially useful to develop a biosensor for <I>in vivo</I> detection of proteins or pathogens in a biological fluid.</P>