Assembly of thin films by means of successive deposition of alternate layers of DNA and poly(allylamine)

Lvov, Y.; Decher, Gero; Sukhorukov, Gleb B.

doi:10.1021/ma00072a016

Cited by 482 publications

(370 citation statements)

References 6 publications

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“…[15][16][17][18][19] A detail understanding of the MEF and its distance dependence nature is vital for its potential application in biomedical sensing. [20][21][22] Layer-by-layer (LbL) assembly [23][24][25][26][27][28][29][30][31][32][33][34][35][36] is based on the sequential adsorption of polycations and polyanions from dilute aqueous solution onto a solid substrate as a consequence of the electrostatic interaction and complex formation between oppositely charged polyelectrolytes. Starting from a functionalized solid substrate, it is possible to adsorb a variety of charged species ranging from polyelectrolytes, nanoparticles, and ionic dyes to many biological agents such as viruses, proteins, and DNA.…”

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

2007

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In the past several years we have demonstrated the metal-enhanced fluorescence (MEF) and the significant changes in the photophysical properties of fluorophores in the presence of metallic nanostructures and nanoparticles. MEF is largely dependent on several factors, such as chemical nature, size, shape of the nanostructure, and its distance from the interrogating fluorophore. Herein, we elucidate the potential of layer-by-layer (LbL) assembly to understand the distance dependence nature of MEF from sulforhodamine B (SRB) assembled on the plasmonic nanostructured surfaces [in the form of Silver Islands films (SIFs)]. The varied proximity of fluorophores from the SIF surfaces was controlled by constructing different numbers of alternate layers of poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH). An anionic laser dye SRB could be electrostatically attached to the positively charged PAH layer. Orientation of the SRB probe molecule adsorbed in PSS/PAH-layered assembly was determined by polarized absorption spectroscopy. The observed tilt angle of the probe transition dipole moment with respect to the surface normal was 40°. Our results show that MEF is indeed distance-dependent. Accordingly, we observed a maximum of a ~6-fold increase in the fluorescence intensity from a monolayer of the SRB at a distance of ~9 nm from the metal-nanostructured surface, with the enhancement decreasing down to ~1.5-fold at about a 30 nm separation distance. Consistently, the minimum lifetimes were about 4-fold shorter than those on glass slides without silver, with the lifetimes being about nearly the same for 15 layers of the PSS/PAH assembly. The intensity-time decays were analyzed with a lifetime distribution model to underpin the distance effect on the metal-fluorophore interaction in the nanometric range. The present study provides improved understanding of the interaction between plasmonic nanostructures and fluorophores and, more importantly, their distance dependence nature, where we used a robust, easy, and inexpensive alternate electrostatic LbL assembly as a bottom-up nanofabrication technique to control the probe distance from the surface.

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Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

2007

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“…However, there are many other interactions that can be used for multilayer deposition such as hydrogen bonds [181], covalent bonds [182] and specific recognition [183]. Thus various materials can be incorporated into the multilayer films such as small molecules [184], macromolecules [158], proteins and DNA [175,[185][186][187]. Polymer selfassembly has been used as substrates for immobilization of immunoglobulin G (IgG) and anti-IgG [175].…”

Section: Introductionmentioning

confidence: 99%

Miniature fiber-optic multicavity Fabry–Perot interferometric biosensor

et al. 2005

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(ABSTRACT)Fiber-optic Fabry-Perot interferometric (FFPI) sensors have been widely used due to their high sensitivity, ease of fabrication, miniature size, and capability for multiplexing. However, direct measurement of self-assembled thin films, receptor immobilization process or biological reaction is limited in the FFPI technique due to the difficulty of forming Fabry-Perot cavities by the thin film itself. Novel methods are needed to provide an accurate and reliable measurement for monitoring the thin-film growth in the nanometer range and under various conditions. In this work, two types of fiber-optic multicavity Fabry-Perot interferometric (MFPI) sensors with built-in temperature compensation were designed and fabricated for thin-film measurement, with applications in chemical and biological sensing. Both the tubing-based MFPI sensor and microgap MFPI sensor provide simple, yet high performance solutions for thin-film sensing. The temperature dependence of the sensing cavity is compensated by extracting the temperature information from a second multiplexed cavity. This provides the opportunity to examine the thin-film characteristics under different environment temperatures.To demonstrate the potential of this structure for practical applications, immunosensors were fabricated and tested using these structures. Self-assembled polyelectrolytes served as a precursor film for immobilization of antibodies to ensure they retain their biological activity. This not only provides a convenient method for protein immobilization but also presents the possibility of increasing the binding capacity

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“…Thus some interesting material can be bonded on the films by chemical interactions such as hydrogen bonds [67], covalent bonds [68], and specific recognition [69]. Much work has been generalized to incorporate molecules, proteins and macromolecules into polymers [62,64,[70][71][72][73]. In this thesis, a probe DNA strand was immobilized onto the polymer surface; meanwhile the probe DNA kept the activity to hybridize with a target DNA strand.…”

Section: Layer-by-layer Electrostatic Self-assembly Methodsmentioning

confidence: 99%

Microgap Structured Optical Sensor for Fast Label-Free DNA Detection

Wang

Cooper

Wang

2008

J. Lightwave Technol.

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DNA detection technology has developed rapidly due to its extensive application in clinical diagnostics, bioengineering, environmental monitoring, and food science areas.Currently developed methods such as surface Plasmon resonance (SPR) methods, fluorescent dye labeled methods and electrochemical methods, usually have the problems of bulky size, high equipment cost and time-consuming algorithms, so limiting their application for in vivo detection. In this work, an intrinsic Fabry-Perot interferometric (IFPI) based DNA sensor is presented with the intrinsic advantages of small size, low cost and corrosion-tolerance. This sensor has experimentally demonstrated its high sensitivity and selectivity.In theory, DNA detection is realized by interrogating the sensor's optical cavity length variation resulting from hybridization event. First, a microgap structure based IFPI sensor is fabricated with simple etching and splicing technology. Subsequently, considering the sugar phosphate backbone of DNA, layer-by-layer electrostatic self-assembly technique is adopted to attach the single strand capture DNA to the sensor endface. When the target DNA strand binds to the single-stranded DNA successfully, the optical cavity length of sensor will be increased. Finally, by demodulating the sensor spectrum, DNA hybridization event can be judged qualitatively.This sensor can realize DNA detection without attached label, which save the experiment expense and time. Also the hybridization detection is finished within a few minutes.This quick response feature makes it more attractive in diagnose application. Since the iii sensitivity and specificity are the most widely used statistics to describe a diagnostic test, so these characteristics are used to evaluate this biosensor. Experimental results demonstrate that this sensor has a sensitivity of 6nmol/ml and can identify a 2 bp mismatch. Since this sensor is optical fiber based, it has robust structure and small size ( 125μm ). If extra etching process is applied to the sensor, the size can be further reduced. This promises the sensor potential application of in-cell detection. Further investigation can be focused on the nanofabrication of this DNA sensor, and this is very meaningful topic not only for diagnostic test but also in many other applications such as food industry, environment monitoring.iv Acknowledgement

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Assembly of thin films by means of successive deposition of alternate layers of DNA and poly(allylamine)

Cited by 482 publications

References 6 publications

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

Polyelectrolyte Layer-by-Layer Assembly To Control the Distance between Fluorophores and Plasmonic Nanostructures

Miniature fiber-optic multicavity Fabry–Perot interferometric biosensor

Microgap Structured Optical Sensor for Fast Label-Free DNA Detection

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