Установка биологической зонды для кварцевых оптических биосенсоров использованием силана связующие вещества

Summary

Биосенсоры взаимодействовать со сложными биологическими средами и выполнение целевого обнаружения, комбинируя высокочувствительные датчики с высокой специфичностью датчиков прилагается к датчику с помощью модификации поверхности. Здесь мы демонстрируем поверхности функционализации кварцевых оптических датчиков с использованием биотина силана связующие вещества для преодоления датчика и биологической среды.

Abstract

In order to interface with biological environments, biosensor platforms, such as the popular Biacore system (based on the Surface Plasmon Resonance (SPR) technique), make use of various surface modification techniques, that can, for example, prevent surface fouling, tune the hydrophobicity / hydrophilicity of the surface, adapt to a variety of electronic environments, and most frequently, induce specificity towards a target of interest.^1-5 These techniques extend the functionality of otherwise highly sensitive biosensors to real-world applications in complex environments, such as blood, urine, and wastewater analysis.^2,6-7 While commercial biosensing platforms, such as Biacore, have well-understood, standard techniques for performing such surface modifications, these techniques have not been translated in a standardized fashion to other label-free biosensing platforms, such as Whispering Gallery Mode (WGM) optical resonators.^8-9

WGM optical resonators represent a promising technology for performing label-free detection of a wide variety of species at ultra-low concentrations.^6,10-12 The high sensitivity of these platforms is a result of their unique geometric optics: WGM optical resonators confine circulating light at specific, integral resonance frequencies.¹³ Like the SPR platforms, the optical field is not totally confined to the sensor device, but evanesces; this “evanescent tail” can then interact with species in the surrounding environment. This interaction causes the effective refractive index of the optical field to change, resulting in a slight, but detectable, shift in the resonance frequency of the device. Because the optical field circulates, it can interact many times with the environment, resulting in an inherent amplification of the signal, and very high sensitivities to minor changes in the environment.^2,14-15

To perform targeted detection in complex environments, these platforms must be paired with a probe molecule (usually one half of a binding pair, e.g. antibodies / antigens) through surface modification.² Although WGM optical resonators can be fabricated in several geometries from a variety of material systems, the silica microsphere is the most common. These microspheres are generally fabricated on the end of an optical fiber, which provides a “stem” by which the microspheres can be handled during functionalization and detection experiments. Silica surface chemistries may be applied to attach probe molecules to their surfaces; however, traditional techniques generated for planar substrates are often not adequate for these three-dimensional structures, as any changes to the surface of the microspheres (dust, contamination, surface defects, and uneven coatings) can have severe, negative consequences on their detection capabilities. Here, we demonstrate a facile approach for the surface functionalization of silica microsphere WGM optical resonators using silane coupling agents to bridge the inorganic surface and the biological environment, by attaching biotin to the silica surface.^8,16 Although we use silica microsphere WGM resonators as the sensor system in this report, the protocols are general and can be used to functionalize the surface of any silica device with biotin.

Protocol

1. Фон Биотин крепится к поверхности эти устройства с помощью простого, три этапа (рис. 1). Во-первых, очистить поверхность и заполните ее гидроксильных групп, подвергая устройства или кислородной плазмы или пиранья решение. Во-вторых, мы используем осаждения паров…

Discussion

Как указано в протоколах, мы создали платформу жилье с помощью которого можно транспортировать кремния микросферы их стебли всей функционализации процесса. Это жилье платформа была создана в качестве решения для поверхностного загрязнения и повреждения, которые привели из микросфер…

Materials

Name of the reagent	Company	Catalogue number	Comments
Methanol	Fisher	67-56-1	ACS grade
Sulfuric Acid	Fisher	8014-95-7	Fuming
Hydrogen Peroxide	Fisher	7722-84-1	30 wt %
Aminopropyltrimethoxysilane	Fisher	13822-56-5
NHS-biotin EZ linker	Pierce	20217
Dimethylsulfoxide	Fisher	67-68-5	Anhydrous
Fluorescein Isothiocyanate	Pierce	46425
Phosphate Buffered Saline	Fisher	7647-14-5	Powder concentrate
Sodium Bicarbonate Buffer	Fisher	NC0099321
Texas Red – Avidin Conjugate	Pierce	A820
Optical Fiber	Newport	F-SC
Fiber Stripper	Fiber Instrument Sales	NN-175	No-Nik 175 um stripper
Kimwipes	Fisher	06666A
Bare Fiber Cleaver	Ilsintech	Cl-03A
Glass Microscope Slides	Fisher	12-550B
Polypropylene Vials	Fisher	03-341-75A	60 mL, hinged cap
Incubating Rocker	VWR	12620-910
Vacuum Desiccator	Fisher	08-594-15B