A photonic crystal based sensing scheme for acetylcholine and acetylcholinesterase inhibitors

Fenzl, Christoph; Genslein, Christa; Zöpfl, Alexander; Baeumner, Antje J.; Hirsch, Thomas

doi:10.1039/c4tb01970a

Cited by 34 publications

(18 citation statements)

References 34 publications

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“…Both types of liposomes show extreme long term stability and keep their physical and hydrodynamic diameters as well as the high negative zeta potential for at least 400 days. 36 This exceeds by far the colloidal stability of numerous other nanomaterials such as polystyrene nanospheres 37,38 or magnetite nanoparticles. 39 Transmission electron microscopy (TEM) images show the successful formation of the liposomes that display good regularity of size and shape (Fig.…”

Section: Resultsmentioning

confidence: 99%

Investigating non-specific binding to chemically engineered sensor surfaces using liposomes as models

Fenzl

Genslein

Domonkos

et al. 2016

Analyst

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Nanoparticles are ubiquitously used for signal enhancement in (bio)sensors, but their true possible performance is typically hampered by non-specific binding. A better understanding of the nature and the prevention of non-specific binding through surface engineering of the particles and sensor surfaces is needed to intelligently design (bio)sensors and potentially avoid bulk blocking methods. Hence, two types of liposomes were used as model for signal-enhancing nanoparticles. Their surface was engineered to bear negative surface charge. One type was synthesized with additional 6 mol% -COOH groups. Their interaction with four typical chemically modified sensor surfaces was then mechanistically characterized by surface plasmon resonance (SPR) spectroscopy. It was shown that the non-specific binding can be described with Langmuir isotherms providing quantitative information of dissociation constants and surface loading with especially high correlation coefficients (>0.97) for all the studied sensor surfaces modified with hydrophilic alkane thiols. By tailoring the sensor surface chemistry, non-specific binding was significantly minimized. Here, carboxyl- or methyl-terminated surfaces performed best. In fact, the pairing of -COOH groups on the sensor surface with -COOH groups on the liposomes almost completely eliminated non-specific binding, resulting in a SPR signal change of only 1 mRIU (refractive index unit) at 100 μM phospholipid concentration. Surprisingly though, -OH groups on the surface, which are also commonly used in sensing applications, did not lead to decreased adsorption, but caused significant signal changes (4 mRIU at 100 μM phospholipid) due to non-specific binding. Overall, the mechanistic studies presented here demonstrate that by careful design of the nanoparticle surface and by choosing sensor surfaces with terminal -CH3 or -COOH groups, improved sensing (micro)systems with very low non-specific adsorption can be obtained.

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Section: Resultsmentioning

confidence: 99%

Investigating non-specific binding to chemically engineered sensor surfaces using liposomes as models

Fenzl

Genslein

Domonkos

et al. 2016

Analyst

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“…Since the slow‐photon effect is induced by light propagating in a PC structure and since it aims to enhance light harvesting by the very same structure, it could be applied in all light‐related applications including photoreactions, optical sensors and photovoltaics . Moreover, which photonic bandgap edge (blue or red) is more efficient in the slow‐photon effect still remains a controversial question.…”

Section: Discussionmentioning

confidence: 99%

Slow Photons for Photocatalysis and Photovoltaics

et al. 2017

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Solar light is widely recognized as one of the most valuable renewable energy sources for the future. However, the development of solar-energy technologies is severely hindered by poor energy-conversion efficiencies due to low optical-absorption coefficients and low quantum-conversion yield of current-generation materials. Huge efforts have been devoted to investigating new strategies to improve the utilization of solar energy. Different chemical and physical strategies have been used to extend the spectral range or increase the conversion efficiency of materials, leading to very promising results. However, these methods have now begun to reach their limits. What is therefore the next big concept that could efficiently be used to enhance light harvesting? Despite its discovery many years ago, with the potential for becoming a powerful tool for enhanced light harvesting, the slow-photon effect, a manifestation of light-propagation control due to photonic structures, has largely been overlooked. This review presents theoretical as well as experimental progress on this effect, revealing that the photoreactivity of materials can be dramatically enhanced by exploiting slow photons. It is predicted that successful implementation of this strategy may open a very promising avenue for a broad spectrum of light-energy-conversion technologies.

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“…The presence of enzyme cleaved ACh into acetic acid and choline. A Donnan potential thus yielded, and allowed a visible detection in the concentration range of 10 −9 –10 −5 mol L −1 . The sensing principle is also suitable for the specific enzymatic hydrolysis of urea via urease, wherein the pH value of reaction media increased …”

Section: Emerging Optical Applications Of Ordered Micro/nanostructuresmentioning

confidence: 98%

Ordered Hybrid Micro/Nanostructures and Their Optical Applications

Zhang

Yang

2019

Advanced Optical Materials

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known that the optical properties related refractive index is an important parameter for ordered micro/nanostructures. Commonly, organic substances own lower refraction. Aiming at improving which, researchers introduce highly polarizable heteroatoms or rigid aromatic moieties. However, the maximum of refractive index is limited to 1.54-1.60, [3] which is far from the requirements of rapidly developing technologies. [4] Incorporation of inorganic materials with relative higher refractive index (TiO 2 , ZnO, ZnS, graphene nanoparticles, and Si) into an organic matrix is capable of enlarging the optical parameters to a great extent, generally up to a value of 2.5-3.0, [5] which offers more chances for the fabrication of novel ordered micro/nanostructures. Photonic crystals (PCs), for example, regularly arrange materials of high and low dielectric constants on the order of the wavelength of light. The photonic bandgap (PBG) prohibiting the propagation of light results from the sufficient dielectric contrast and appropriate geometry. The structural color therefore generates. Manipulating the propagation of light via micro/nanostructures meets the requirements for modern optical devices. [6] As a result, more efforts have been applied to devices consisting of micro/nanostructures of multiple materials, such as synthetic materials and biomaterials. [7] Besides optical properties, the strength and toughness of ordered micro/nanostructures are also improved based on the hybrid material. Meanwhile, the electric and magnetic features of inorganic dopants can also exactly assist the adjustability. Therefore, the hybrid can significantly improve performance compared with its constituent.This review emphasizes on applications sought (sensing, imaging, communication, photoelectricity, etc.), the materials used (silicon, metals, polymers, etc.), and the preparation methods employed (patterning, etching, deposition, etc.). We present an attempt to classify and compare some intensively reported micro/nanostructures of hybrid materials and/or heterogeneous structures, along with recent important developments in literatures. It is organized as follows: First, we summarize some fundamental physical principles and concepts in brief. Second, we particularly highlight artificial and natural laminar structures, represented by Bragg stacks (BSs) and butterfly wings, which have drawn much attention in the latest literatures. Next, the focus shifts to the preparation routes and materials adoption of colloidal crystals and their derived periodic arrays. A few examples of highly functional materials Recent advances in manufacturing and technology of ordered hybrid micro/ nanostructures have acquired many breakthroughs. With the aid of the cooperation of various materials, the ordered hybrid micro/nanostructures exhibit high-quality performance and mechanical stability and allow the modulation on the light-matter interaction in a controllable manner, thereby enabling a wide variety of innovative applications. This article reviews recent deve...

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A photonic crystal based sensing scheme for acetylcholine and acetylcholinesterase inhibitors

Abstract: A 2-layer approach towards optical sensing of acetylcholine and detection of an acetylcholinesterase inhibitor using photonic crystal sensor technology.

Cited by 34 publications

References 34 publications

Investigating non-specific binding to chemically engineered sensor surfaces using liposomes as models

Investigating non-specific binding to chemically engineered sensor surfaces using liposomes as models

Slow Photons for Photocatalysis and Photovoltaics

Ordered Hybrid Micro/Nanostructures and Their Optical Applications

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