Mechanistic study for immobilization of cysteine-labeled oligopeptides on UV-activated surfaces

Ong, Irvine Lian Hao; Ding, Xiaokang; Yang, Kun‐Lin

doi:10.1016/j.colsurfb.2014.05.042

Cited by 10 publications

(6 citation statements)

References 28 publications

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“…29 In LC-based immunodetection, proteins or antibodies are immobilized on a glass substrate coated with an alignment layer consisting of silane surfactants such as dimethyloctadecyl [3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP). 35,36 Exposure to UV irradiation results in degradation of the alkylsiloxane self-assembled monolayer, and functional groups such as ─COOH, ─CHO, and ─OH are generated on the UV-irradiated surface, which tends to become more hydrophilic. In order to enhance the binding affinity of the LC aligning agent, modification of DMOAP with ultraviolet (UV) light is expected to provide functional groups that enhance binding between the alignment layer and biomolecules.…”

Section: Introductionmentioning

confidence: 99%

Surface modification of alignment layer by ultraviolet irradiation to dramatically improve the detection limit of liquid-crystal-based immunoassay for the cancer biomarker CA125

Lee

2015

J. Biomed. Opt

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Liquid crystal (LC)-based biosensing has attracted much attention in recent years. We focus on improving the detection limit of LC-based immunoassay techniques by surface modification of the surfactant alignment layer consisting of dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP). The cancer biomarker CA125 was detected with an array of anti-CA125 antibodies immobilized on the ultraviolet (UV)-modified DMOAP monolayer. Compared with a pristine counterpart, UV irradiation enhanced the binding affinity of the CA125 antibody and reproducibility of immunodetection in which a detection limit of 0.01 ng∕ml for the cancer biomarker CA125 was achieved. Additionally, the optical texture observed under a crossed polarized microscope was correlated with the analyte concentration. In a proof-of-concept experiment using CA125-spiked human serum as the analyte, specific binding between the CA125 antigen and the anti-CA125 antibody resulted in a distinct and concentration-dependent optical response despite the high background caused by nonspecific binding of other biomolecules in the human serum. Results from this study indicate that UVmodification of the alignment layer, as well as detection with LCs of large birefringence, contributes to the enhanced performance of the label-free LC-based immunodetection, which may be considered a promising alternative to conventional label-based methods.

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Section: Introductionmentioning

confidence: 99%

Surface modification of alignment layer by ultraviolet irradiation to dramatically improve the detection limit of liquid-crystal-based immunoassay for the cancer biomarker CA125

Lee

2015

J. Biomed. Opt

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“…In order to evaluate this observation, a mixture of 1 mg mL −1 BSA and 5 µM of Cu 2+ was immobilized upon unmodified and UV-modified DMOAP-coated glass slide surfaces and characterized through polarized optical microscope (POM) using LC as a transducer. The unmodified DMOAP-coated surface has only an alkyl group at its terminus, whereas in the UV-modified DMOAP surfaces, both aldehydic and carboxylic functional groups were generated under different exposure times [21]. The optical images of LC given in Figure 1a revealed that the UV-activated DMOAP surface adsorbed greater amounts of BSA as compared to the unmodified DMOAP-coated surface shown in Figure 1b.…”

Section: The Effect Of Modified and Unmodified Dmoap Surfaces On Immomentioning

confidence: 97%

Bovine Serum Albumin Protein-Based Liquid Crystal Biosensors for Optical Detection of Toxic Heavy Metals in Water

Amin

Siddiqi

Lin

et al. 2020

Sensors

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A new methodology involving the use of Bovine Serum Albumin (BSA) as a probe and liquid crystal (LC) as a signal reporter for the detection of heavy metal ions in water at neutral pH was developed. BSA acted as a multi-dentate ligand for the detection of multiple metal ions. The LC sensor was fabricated by immobilizing 3 µg mL−1 BSA solution on dimethyloctadecyl-[3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP)-coated glass slides. In the absence of heavy metal ions, a dark optical image was observed, while in their presence, a dark optical image turned to bright. The optical response was characterized by using a polarized optical microscope (POM). The BSA based LC sensor selectively detected toxic metal ions as compared to s block metal ions and ammonium ions in water. Moreover, the limit of detection was found to be very low (i.e., 1 nM) for the developed new biosensor in comparison to reported biosensors.

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“…To further, confirm that either the alcohol or aldehyde functional groups are responsible for immobilization of oligopeptide. The DMOAP SAM-CH 3 was irradiated under UV to oxidize the terminal alkyl group to À CHO functional group, [23] upon which three different oligopeptide(ligand 1, ligand 2 and ligand 3) were immobilized and analyzed via FMS (Figure 1). However, in another case before immobilization of oligopeptides the oxidized surface was treated with NaBH 4 to reduce all À CHO groups into alcohol functional groups (À COH).…”

Section: The Immobilization Of Oligopeptide At the Aldehyde Functionalized Surface Was Investigated Through Fmsmentioning

confidence: 99%

Fabrication of a Fluorophore/Liquid‐Crystal‐Based Oligopeptide Biosensor for the Detection of Cu (II) Ions

et al. 2021

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A new sensing methodology has been developed for the detection of Cu(II) ions in water by using biotinylated oligopeptide as a probe whereas liquid crystal (LC) and fluorophore were used as signal reporters. The multidentate oligopeptide ligand was used to investigate Cu(II) as a model metal ion. The alkyl terminal group of the coated dimethyl octadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP) was first activated to aldehydic functional group by UV irridiation for 50 seconds. The activated aldehydic functional group was covalent linked with biotinylated oligopeptide via thiolation reaction. As fabricated oligopeptide probe spotted with metal ions was incubated for 30 minutes and followed by tagging with streptavidin-cyanine-3 as a fluorophore. Polarized optical microscopy (POM) and fluorescence microarray scanner (FMS) were used as characterization techniques. The developed sensing methodology results were reproducible for different concentrations of model Cu (II) ions as confirmed from the characterization techniques. Our methodology highlighted the detection of Cu(II) ions in water as low as 100 nM, and is the lowest concentration so far reported.

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Mechanistic study for immobilization of cysteine-labeled oligopeptides on UV-activated surfaces

Cited by 10 publications

References 28 publications

Surface modification of alignment layer by ultraviolet irradiation to dramatically improve the detection limit of liquid-crystal-based immunoassay for the cancer biomarker CA125

Surface modification of alignment layer by ultraviolet irradiation to dramatically improve the detection limit of liquid-crystal-based immunoassay for the cancer biomarker CA125

Bovine Serum Albumin Protein-Based Liquid Crystal Biosensors for Optical Detection of Toxic Heavy Metals in Water

Fabrication of a Fluorophore/Liquid‐Crystal‐Based Oligopeptide Biosensor for the Detection of Cu (II) Ions

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