Simple and Label‐Free Liquid Crystal‐based Optical Sensor for Highly Sensitive and Selective Endotoxin Detection by Aptamer Binding and Separation. Issue 4 (29th January 2019)

• Record Type: Journal Article
• Authors: An, Zongfu; Jang, Chang‐Hyun
• Is Part Of: ChemistrySelect. Volume 4:Issue 4(2019)
• Page Start: 1416
• Page End: 1422
• Publication Date: 2019-01-29
• Subjects: lipopolysaccharide -- liquid crystal -- 4-cyano-4′-pentylbiphenyl -- optical biosensors -- polarized optical microscope; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201803774
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: Lipopolysaccharides (LPS), also commonly known as lipoglycans and endotoxins, can often accidentally contaminate recombinant protein therapeutics and bacteria‐derived plasmid DNA vaccines. Since LPS can induce fever, hypotension, shock, and even death, their early and sensitive detection is necessary in relevant bioassays and for parenteral drug administration and/or biotherapeutics. In this study, an optical biosensor was developed using LPS‐specific single‐stranded DNA aptamers as LPS‐selective probes. (3‐Aminopropyl) triethoxysilane and glutaraldehyde were used as linkers to immobilize the LPS high‐affinity aptamer on glass. Subsequently, each modification step was characterized by the optical responses obtained from liquid crystals using a polarized optical microscope. The sensor's ability to detect LPS was confirmed using a broad LPS detection range (5.5 pg/mL ‐ 100 ng/mL). Despite the presence of plasmid DNA, RNA, and bovine serum albumin, the aptamer sensor showed high selectivity for LPS and could be regenerated for reuse at a low pH, thus, providing a promising option for detecting LPS in complex, low pH environments. Abstract : The schematic setup of the reported endotoxin‐specific aptasensor and the sensing mechanism. With a modified sandwich form of optical cell, the binding of DMOAP, sufficient fixed slit causes a homeotropic orientation of 5CB, resulting in a dark image. With the addition of endotoxin in the system, the binding of endotoxin to endotoxin‐specific aptamer cause changes of surface topography, a bright image results from surface morphology changes and a homeotropic‐to‐planar orientation transition.