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2200 KiB

Open AccessArticle

Synthesis of a Cu²⁺-Selective Probe Derived from Rhodamine and Its Application in Cell Imaging

by Chunwei Yu, Yingying Wen and Jun Zhang

Sensors 2014, 14(11), 21375-21384; https://doi.org/10.3390/s141121375 - 12 Nov 2014

Cited by 12 | Viewed by 6214

Abstract

A new fluorescent probe P based on rhodamine for Cu²⁺ was synthesized and characterized. The new probe P showed high selectivity to Cu²⁺ over other tested metal ions. With optimal conditions, the proposed probe P worked in a wide linear range [...] Read more.

A new fluorescent probe P based on rhodamine for Cu²⁺ was synthesized and characterized. The new probe P showed high selectivity to Cu²⁺ over other tested metal ions. With optimal conditions, the proposed probe P worked in a wide linear range of 1.0 × 10⁻⁶–1.0 × 10⁻⁵ M with a detection limit of 3.3 × 10⁻⁷ M Cu²⁺ in ethanol-water solution (9:1, v:v, 20 mM HEPES, pH 7.0). Furthermore, it has been used for imaging of Cu²⁺ in living cells with satisfying results. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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4768 KiB

Open AccessArticle

Nitrogen-Rich Multinuclear Ferrocenophanes as Multichannel Chemosensor Molecules for Transition and Heavy-Metal Cations

by Antonia Sola, Arturo Espinosa, Alberto Tárraga and Pedro Molina

Sensors 2014, 14(8), 14339-14355; https://doi.org/10.3390/s140814339 - 7 Aug 2014

Cited by 14 | Viewed by 6126

Abstract

[m.n] Multinuclear ferrocenophanes prepared by aza-Wittig reaction of bisiminophosphoranes derived from 1,1'-diazidoferrocene and isophthaladelhyde or 2,5-diformylthiophene, behave as efficient electrochemical and chromogenic chemosensor molecules for Zn²⁺, Pb²⁺, and Hg²⁺ metal cations. Whereas the OSWV of receptor 3, [...] Read more.

[m.n] Multinuclear ferrocenophanes prepared by aza-Wittig reaction of bisiminophosphoranes derived from 1,1'-diazidoferrocene and isophthaladelhyde or 2,5-diformylthiophene, behave as efficient electrochemical and chromogenic chemosensor molecules for Zn²⁺, Pb²⁺, and Hg²⁺ metal cations. Whereas the OSWV of receptor 3, bearing two m-phenylene units in the bridges, display one oxidation peak, receptor 4 incorporating two thiophene rings in the bridges, exhibits two well-separated oxidation peaks. In both receptors only the addition of Zn²⁺, Pb²⁺, and Hg²⁺ metal cations induced a remarkable anodic shift of ferrocene/ferrocenium redox couple. Likewise, in the absorption spectra of these receptors the low energy band is red-shifted by Δλ = 165 − 209 nm, and these changes promoted a significant color changes which could be used for the naked eye detection of these metal cations. The coordination modes for two representative cases were unveiled by DFT calculations that show an unsual coordination in the [4₂Pb]²⁺ complex with the Pb²⁺ cation in a distorted cubic N₄S₄ donor cage. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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1042 KiB

Open AccessArticle

Anion Binding Studies on Receptors Derived from the Indolo[2,3-a]carbazole Scaffold Having Different Binding Cavity Sizes

by Guzmán Sánchez, David Curiel, Alberto Tárraga and Pedro Molina

Sensors 2014, 14(8), 14038-14049; https://doi.org/10.3390/s140814038 - 31 Jul 2014

Cited by 5 | Viewed by 6051

Abstract

The indolo[2,3-a]carbazole scaffold is a fused polyheteroaromatic system bearing two NH groups which suitably converge as hydrogen bond donor sites for the recognition of anions. A simple derivatisation of the indolocarbazole system at positions 1 and 10 with different functional groups, [...] Read more.

The indolo[2,3-a]carbazole scaffold is a fused polyheteroaromatic system bearing two NH groups which suitably converge as hydrogen bond donor sites for the recognition of anions. A simple derivatisation of the indolocarbazole system at positions 1 and 10 with different functional groups, namely alcohols and amides, has contributed to modulate the anion binding selectivity and sensibility. A particularly good response has been obtained for the benzoate anion. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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1451 KiB

Open AccessArticle

Electrophoresis-Enhanced Detection of Deoxyribonucleic Acids on a Membrane-Based Lateral Flow Strip Using Avian Influenza H5 Genetic Sequence as the Model

by Jui-Chuang Wu, Chih-Hung Chen, Ja-Wei Fu and Huan-Ching Yang

Sensors 2014, 14(3), 4399-4415; https://doi.org/10.3390/s140304399 - 5 Mar 2014

Cited by 16 | Viewed by 9164

Abstract

This study reports a simple strategy to detect a deoxyribonucleic acid (DNA) on a membrane-based lateral flow (MBLF) strip without tedious gel preparation, gel electrophoresis, and EtBr-staining processes. The method also enhances the detection signal of the genetic sample. A direct electric field [...] Read more.

This study reports a simple strategy to detect a deoxyribonucleic acid (DNA) on a membrane-based lateral flow (MBLF) strip without tedious gel preparation, gel electrophoresis, and EtBr-staining processes. The method also enhances the detection signal of the genetic sample. A direct electric field was applied over two ends of the MBLF strips to induce an electrophoresis of DNAs through the strips. The signal enhancement was demonstrated by the detection of the H5 subtype of avian influenza virus (H5 AIV). This approach showed an excellent selectivity of H5 AIV from other two control species, Arabidopsis thaliana and human PSMA5. It also showed an effective signal repeatability and sensitivity over a series of analyte concentrations. Its detection limit could be enhanced, from 40 ng to 0.1 ng by applying 12 V. The nano-gold particles for the color development were labeled on the capture antibody, and UV-VIS and TEM were used to check if the labeling was successful. This detection strategy could be further developed to apply on the detection of drug-allergic genes at clinics or detection of infectious substances at incident sites by a simple manipulation with an aid of a mini-PCR machine and auxiliary kits. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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Review

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583 KiB

Open AccessReview

CMOS Time-Resolved, Contact, and Multispectral Fluorescence Imaging for DNA Molecular Diagnostics

by Nan Guo, Ka Wai Cheung, Hiu Tung Wong and Derek Ho

Sensors 2014, 14(11), 20602-20619; https://doi.org/10.3390/s141120602 - 31 Oct 2014

Cited by 14 | Viewed by 8226

Abstract

Instrumental limitations such as bulkiness and high cost prevent the fluorescence technique from becoming ubiquitous for point-of-care deoxyribonucleic acid (DNA) detection and other in-field molecular diagnostics applications. The complimentary metal-oxide-semiconductor (CMOS) technology, as benefited from process scaling, provides several advanced capabilities such as [...] Read more.

Instrumental limitations such as bulkiness and high cost prevent the fluorescence technique from becoming ubiquitous for point-of-care deoxyribonucleic acid (DNA) detection and other in-field molecular diagnostics applications. The complimentary metal-oxide-semiconductor (CMOS) technology, as benefited from process scaling, provides several advanced capabilities such as high integration density, high-resolution signal processing, and low power consumption, enabling sensitive, integrated, and low-cost fluorescence analytical platforms. In this paper, CMOS time-resolved, contact, and multispectral imaging are reviewed. Recently reported CMOS fluorescence analysis microsystem prototypes are surveyed to highlight the present state of the art. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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3146 KiB

Open AccessReview

Recent Advances in the Field of Bionanotechnology: An Insight into Optoelectric Bacteriorhodopsin, Quantum Dots, and Noble Metal Nanoclusters

by Christopher Knoblauch, Mark Griep and Craig Friedrich

Sensors 2014, 14(10), 19731-19766; https://doi.org/10.3390/s141019731 - 22 Oct 2014

Cited by 27 | Viewed by 9806

Abstract

Molecular sensors and molecular electronics are a major component of a recent research area known as bionanotechnology, which merges biology with nanotechnology. This new class of biosensors and bioelectronics has been a subject of intense research over the past decade and has found [...] Read more.

Molecular sensors and molecular electronics are a major component of a recent research area known as bionanotechnology, which merges biology with nanotechnology. This new class of biosensors and bioelectronics has been a subject of intense research over the past decade and has found application in a wide variety of fields. The unique characteristics of these biomolecular transduction systems has been utilized in applications ranging from solar cells and single-electron transistors (SETs) to fluorescent sensors capable of sensitive and selective detection of a wide variety of targets, both organic and inorganic. This review will discuss three major systems in the area of molecular sensors and electronics and their application in unique technological innovations. Firstly, the synthesis of optoelectric bacteriorhodopsin (bR) and its application in the field of molecular sensors and electronics will be discussed. Next, this article will discuss recent advances in the synthesis and application of semiconductor quantum dots (QDs). Finally, this article will conclude with a review of the new and exciting field of noble metal nanoclusters and their application in the creation of a new class of fluorescent sensors. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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2383 KiB

Open AccessReview

Boron Nitride Nanotubes for Spintronics

by Kamal B. Dhungana and Ranjit Pati

Sensors 2014, 14(9), 17655-17685; https://doi.org/10.3390/s140917655 - 22 Sep 2014

Cited by 53 | Viewed by 11935

Abstract

With the end of Moore’s law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current [...] Read more.

With the end of Moore’s law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR) effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT), which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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2821 KiB

Open AccessReview

The Intersection of CMOS Microsystems and Upconversion Nanoparticles for Luminescence Bioimaging and Bioassays

by Liping Wei, Samer Doughan, Yi Han, Matthew V. DaCosta, Ulrich J. Krull and Derek Ho

Sensors 2014, 14(9), 16829-16855; https://doi.org/10.3390/s140916829 - 10 Sep 2014

Cited by 13 | Viewed by 8941

Abstract

Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs) offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs [...] Read more.

Organic fluorophores and quantum dots are ubiquitous as contrast agents for bio-imaging and as labels in bioassays to enable the detection of biological targets and processes. Upconversion nanoparticles (UCNPs) offer a different set of opportunities as labels in bioassays and for bioimaging. UCNPs are excited at near-infrared (NIR) wavelengths where biological molecules are optically transparent, and their luminesce in the visible and ultraviolet (UV) wavelength range is suitable for detection using complementary metal-oxide-semiconductor (CMOS) technology. These nanoparticles provide multiple sharp emission bands, long lifetimes, tunable emission, high photostability, and low cytotoxicity, which render them particularly useful for bio-imaging applications and multiplexed bioassays. This paper surveys several key concepts surrounding upconversion nanoparticles and the systems that detect and process the corresponding luminescence signals. The principle of photon upconversion, tuning of emission wavelengths, UCNP bioassays, and UCNP time-resolved techniques are described. Electronic readout systems for signal detection and processing suitable for UCNP luminescence using CMOS technology are discussed. This includes recent progress in miniaturized detectors, integrated spectral sensing, and high-precision time-domain circuits. Emphasis is placed on the physical attributes of UCNPs that map strongly to the technical features that CMOS devices excel in delivering, exploring the interoperability between the two technologies. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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3395 KiB

Open AccessReview

Experimental Tools to Study Molecular Recognition within the Nanoparticle Corona

by Markita P. Landry, Sebastian Kruss, Justin T. Nelson, Gili Bisker, Nicole M. Iverson, Nigel F. Reuel and Michael S. Strano

Sensors 2014, 14(9), 16196-16211; https://doi.org/10.3390/s140916196 - 2 Sep 2014

Cited by 44 | Viewed by 10520

Abstract

Advancements in optical nanosensor development have enabled the design of sensors using synthetic molecular recognition elements through a recently developed method called Corona Phase Molecular Recognition (CoPhMoRe). The synthetic sensors resulting from these design principles are highly selective for specific analytes, and demonstrate [...] Read more.

Advancements in optical nanosensor development have enabled the design of sensors using synthetic molecular recognition elements through a recently developed method called Corona Phase Molecular Recognition (CoPhMoRe). The synthetic sensors resulting from these design principles are highly selective for specific analytes, and demonstrate remarkable stability for use under a variety of conditions. An essential element of nanosensor development hinges on the ability to understand the interface between nanoparticles and the associated corona phase surrounding the nanosensor, an environment outside of the range of traditional characterization tools, such as NMR. This review discusses the need for new strategies and instrumentation to study the nanoparticle corona, operating in both in vitro and in vivo environments. Approaches to instrumentation must have the capacity to concurrently monitor nanosensor operation and the molecular changes in the corona phase. A detailed overview of new tools for the understanding of CoPhMoRe mechanisms is provided for future applications. Full article

(This article belongs to the Special Issue Molecular Sensing and Molecular Electronics)

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