Smart Molecules Research Articles

Electrofluorochromism: from molecular systems to set-up and display

Electrofluorochromism deals with electrochemical monitoring of luminescence features. There are several reasons to be interested in that field. The first one is the design of displays working in a similar way to electrochromic devices, substituting colors due to absorption with colors due to emission, thus producing much higher brilliance. This requires designing smart molecules and materials, which are likely to exhibit reversible switch of emission by controlling their redox state. There are also a lot of analytical applications, especially in biochemical issues, where in situ dual detection of electrochemical and fluorescence signals can lead to very sensitive and selective biosensors. To achieve this goal, instrumental developments are necessary, involving, among others, beyond diffraction limit and single molecule detection optical techniques. This paper reviews the most recent developments in the above mentioned fields of fluorescence spectroelectrochemistry, coupled detection of fluorescence and electrochemical signals and design of molecules and materials exhibiting electrofluorochromic properties. The first part describes the required features for molecular systems to exhibit a reversible switch in their luminescence properties according to a change in their redox state. Examples among organic and organometallic dyes and redox labelled fluorophores are listed. The second part focuses on the instrumental development in fluorescence spectroelectrochemistry and recent coupling of electrochemical techniques with fluorescence microscopy. Finally, some applications and devices are presented in the last part of this review. This should give an overview of this emerging research field at the interface between physics, chemistry and biology.

Understanding the targeting of the RB family proteins by viral oncoproteins to defeat their oncogenic machinery

The retinoblastoma (RB) family consists of three genes, RB1, RBL1, and RBL2, that code for the pRb, p107, and pRb2/p130 proteins, respectively. All these factors have pivotal roles in controlling fundamental cellular mechanisms such as cell cycle, differentiation and apoptosis. The founder and the most investigated RB family protein is pRb, which is considered to be the paradigm of tumor suppressors. However, p107 and pRb2/p130 clearly display a high degree of structural and functional homology with pRb. Interestingly, these factors were first identified as physical targets of the Adenovirus E1A oncoprotein. Indeed, RB family proteins are the most important and widely investigated targets of small DNA virus oncoproteins, such as Adenovirus E1A, human papillomavirus E7 and Simian virus 40 large T antigen. By interacting with pRb and with other RB family members, these oncoproteins neutralize their growth suppressive properties, thus stimulating proliferation of the infected cells, de-differentiation, and resistance to apoptosis. All these acquired features strongly favor the rise and selection of immortalized and mutation-prone cells, leading to a higher propensity in undergoing transformation. Our present work aims to illustrate and delve into these protein-protein interactions. Considering that these viral oncoproteins are dispensable for normal cellular functions, they can create "oncogene addiction" in the infected/transformed cells. This makes the possibility to dismantle these interactions extremely attractive, thus promoting the development of highly specific smart molecules capable of targeting only the infected/transformed cells that express these viral factors.

Quartz crystal microbalance with dissipation (QCM-D) as tool to exploit antigen–antibody interactions in pancreatic ductal adenocarcinomadetection

Novel synthetic peptides represent smart molecules for antigen–antibody interactions in several bioanalytics applications, from purification to serum screening. Their immobilization onto a solid phase is considered a key point for sensitivity increasing. In this view, we exploited Quartz Crystal Microbalance with simultaneous frequency and dissipation monitoring (QCM-D) with a double aim, specifically, as investigative tool for spacers monolayer assembling and its functional evaluation, as well as high sensitive method for specific immunosorbent assays. The method was applied to pancreatic ductal adenocarcinoma (PDAC) detection by studying the interactions between synthetic phosphorylated and un-phosphorylated α-enolase peptides with sera of healthy and PDAC patients. The synthetic peptides were immobilized on the gold surface of the QCM-D sensor via a self-assembled alkanethiol monolayer. The presented experimental results can be applied to the development of surfaces less sensitive to non-specific interactions with the final target to suggest specific protocols for detecting PDAC markers with un-labeled biosensors.

Benzylic Amide Rotaxanes: A Versatile Architecture

Rotaxanes are currently seen as one of the most promising components in artificial molecular machines. In the last few decades, much effort has been dedicated to the developing of such interlocked architectures, which can be subjected to different types of submolecular motion. The field of Rotaxanes has evolved to stimuli-responsive molecular shuttle, capable of responding to several different external stimuli. The interest in molecular shuttles arises from the possibility of achieving controlled submolecular motion of their components with respect to one another. Here, we present an overview of benzylic amide rotaxanes, smart molecules able to function as electrochemically switchable molecular shuttles, both in solution and on surfaces. Transposing working systems from the solution phase onto surfaces and into the solid state is fundamental for their applicability in different technological fields including electromechanical switches and molecular electronic devices. The synthesis of benzylic amide rotaxanes is based on template effects mediated by hydrogen bonds, which play a key role also in the shuttling process. Given the electrostatic nature of hydrogen bonds, their interactions can be modulated through injection of electrons. Electrochemistry seems to be a powerful reagent-free tool to operate stimulus and characterize the molecular level motion across different environments, necessary from the point of view of future integration with current technologies. Keywords: Benzylic Amide Rotaxanes, Clipping strategies, Electrochemistry, Hydrogen bonding, Interlocked molecules, Molecular shuttles, Naphthalimides redox properties, Template synthesis

Construction of biomimetic smart nanochannels with polymer membranes and application in energy conversion systems

Learning from nature has inspired the creation of intelligent devices to meet the increasing needs of the advanced community and also to better understand how to imitate biology. As one of biomimetic nanodevices, nanochannels or nanopores aroused particular interest because of their potential applications in nanofluidic devices, biosensing, filtration, and energy conversions. In this review we have summarized some recent results mainly focused on the design, construction and application in energy conversion systems. Like biological nanochannels, the prepared smart artificial nanochannels fabricated by ion track-etched polymer membranes and smart molecules show a great potential in the field of bioengineering and biotechnology. And these applications can not only help people to know and understand the living processes in nature, but can also inspire scientists to study and develop novel nanodevices with better performance for the mankind.

Smart molecules at work—mimicking advanced logic operations

Molecular logic is an interdisciplinary research field, which has captured worldwide interest. This tutorial review gives a brief introduction into molecular logic and Boolean algebra. This serves as the basis for a discussion of the state-of-the-art and future challenges in the field. Representative examples from the most recent literature including adders/subtractors, multiplexers/demultiplexers, encoders/decoders, and sequential logic devices (keypad locks) are highlighted. Other horizons, such as the utility of molecular logic in bio-related applications, are discussed as well.

Nanoparticle Delivery: Targeting and Nonspecific Binding

AbstractTargeted cancer therapies focus on molecular and cellular changes that are specific to cancer and hold the promise of harming fewer normal cells, reducing side effects, and improving the quality of life. One major challenge in cancer nanotechnology is how to selectively deliver nanoparticles to diseased tissues while simultaneously minimizing the accumulation onto the nanoparticle of unwanted materials (e.g., proteins in the blood) during the delivery process. Once therapeutic nanoparticles have been created, very often they are linked or coated to other molecules that assist in targeting the delivery of nanoparticles to different cell types of the body. These linkers or coatings have been termed targeting ligands or “smart molecules” because of their inherent ability to direct selective binding to cell types or states and, therefore, confer “smartness” to nanoparticles. Likewise, “smartness” can be imparted to the nanoparticles to selectively repel unwanted entities in the body. To date, such smart molecules can consist of peptides, antibodies, engineered proteins, nucleic acid aptamers, or small organic molecules. This review describes how such smart molecules are discovered, enhanced, and anchored to nanoparticles, with an emphasis on how to minimize nonspecific interactions of nanoparticles to unintended targets.

Gaucher disease: New developments in treatment and etiology

Gaucher disease (GD) is an autosomal recessive disease which if undiagnosed or diagnosed late results in devastating complications. Because of the heterozygous nature of GD, there is a wide spectrum of clinical presentation. Clinicians should be aware of this rare but potentially treatable disease in patients who present with unexplained organomegaly, anemia, massive splenomegaly, ascites and even cirrhosis of unknown origin. The treatment options for adult type GD include enzyme replacement treatment (ERT) and substrate reduction treatment (SRT) depending on the status of the patient. Future treatment options are gene therapy and "smart molecules" which provide specific cure and additional treatment options. In this review, we present the key issues about GD and new developments that gastroenterologists should be aware of.

Bio-inspired Programmable Self-assembly on DNA Templates

Abstract Besides the biological importance of DNA as storage of genetic information, DNA is a smart molecule to assemble functional units since it is possible to use sequences of nucleobases to encode molecularly assembled systems in a predetermined fashion over a wide range in size. This review highlights recent advance in precise control of molecular assembly on DNA templates directed towards functionalized materials.

Micro- and nanotechnologies: dullish electrons and smart molecules

Abstract The article gives elements to answer a few questions: • Are Nanotechnologies a logical and rational continuation of Microtechnologies or do they represent a revolution in many aspects of Sciences and Technologies? • What are the conditions to be able to combine long term basic sciences and innovations which can be rapidly transferred in the industry (or on the ‘market’). To cite this article: J. Simon, C. R. Chimie 8 (2005).

Optical sensor with active matrix built from polyelectrolytes–smart molecules mixture

Light propagating in optical fibres totally reflects from internal glass surfaces, but to some extent optical energy known as evanescent waves crosses glass surfaces and penetrates the surroundings of the optic fibre core. Thin films, built on the surface of optic fibre enriched in smart molecules, changes the spectroscopic properties under influence of the surrounding conditions, and may serve as an active matrix for optic sensors. We have synthesised two polyelectrolytes with aliphatic main chains: one with anionic groups (sulfonated poly(vinyl alcohol)) and a second one with cationic groups (quaternized poly( N,N-dialkylaminoalkylacrylamide)). Thin films composed of up to 50 polyelectrolyte pairs were characterised by contact angle, ellipsometric, and UV-visible spectral measurements. Thin films composed from aliphatic polyelectrolytes and smart molecules, viz. fluorescent dye (eosin) and pH-sensitive dye (phenol red), were deposited on the surface of etched optic fibres. The possibility of pH-sensitive quenching of eosin fluorescence was examined.

Macromolecular smart materials and structures

Macromolecules offer many ways of creating smart materials. New capabilities for the predictive design of polymer molecules are coming from the rapid advances in computer modelling of the structure and properties of large molecules. Powerful chemical methods for the creation of polymeric modules that can be assembled in a variety of ways to perform useful, smart molecule functions are available. It has only recently become possible to observe directly segments of polymer molecules attached to solid surfaces, thanks to the techniques of scanning tunnelling microscopy and atomic force microscopy. This paper describes a combined approach, utilizing these new capabilities, to the design, synthesis and characterization of a smart macromolecule which can function to control damage at the interface between a polymer matrix and a reinforcing fibre, and can also provide a colour change which will reveal the presence of the damaged region.