Nanowire electron scattering spectroscopy

Methods and devices for spectroscopic identification of molecules using nanoscale wires are disclosed. According to one of the methods, nanoscale wires are provided, electrons are injected into the nanoscale wire; and inelastic electron scattering is measured via excitation of low-lying vibrational energy levels of molecules bound to the nanoscale wire

Electrical Conductance in Biological Molecules

Nucleic acids and proteins are not only biologically important polymers: They have recently been recognized as novel functional materials surpassing in many aspects the conventional ones. Although Herculean efforts have been undertaken to unravel fine functioning mechanisms of the biopolymers in question, there is still much more to be done. This particular paper presents the topic of biomolecular charge transport, with a particular focus on charge transfer/transport in DNA and protein molecules. Here the experimentally revealed details, as well as the presently available theories, of charge transfer/transport along these biopolymers are critically reviewed and analyzed. A summary of the active research in this field is also given, along with a number of practical recommendations.Comment: v2: This paper has been withdrawn by the authors due to a serious complaints from one author whose work we cite. v3: After clarifying the issue we are herewith republishing our paper

Клинические применения биосенсоров на основе полевых транзисторов с углеродными нанотрубками или нанопроводами

В цій статті ми описуємо останні досягнення в стрімко розвиваній області детектування аналітів з використанням польових транзисторів (ПТ) на основі вуглецевих нанотрубок і нанопроводів. У цій статті відображено поведінку та переваги одновимірних наноматеріалів для використання в біосенсорах. Поміж одновимірних нанометрових матеріалів вуглецеві нанотрубки і нанопроводи пропонують унікальні електронні та механічні властивості, які роблять їх надзвичайно привабливими для задач біодетектування. Проаналізовано структури і принципи роботи ПТ-біосенсорів на основі вуглецевих нанотрубок / нанопроводів. Польові транзистори на основі вуглецевих нанотрубок / кремнієвих нанопроводів останнім часом привертають до себе величезну увагу як перспективні інструменти для проектування біосенсорів, через їх біосумісність, сумісності за розміром, ультрачутливість, селективність, а також можливості без маркерного виявлення в режимі реального часу. Крім того, також проаналізовано механізми взаємодії між елементами трансдьюсера ПТ-біосенсора (вуглецевими нанотрубками або нанопроводами) та біооб'єктами. На закінчення, в цьому огляді основна увага приділяється застосуванню біосенсорів на основі польових транзисторів для вимірювання різних аналітів. Показано взаємодію білків, реакцію антитіло-антиген, включаючи реакцію виявлення простатспецифічного антигену, ДНК-гібридизацію і ферментативні реакції за участі глюкози.In this paper we describe recent advances in the rapidly developing area of analyte detection using field-effect transistors (FETs)based on carbon nanotubes or nanowires. In this article behavior and advantages of onedimensional nanomaterials for biosensing application is depicted. Among onedimensional nanometer-scale materials, carbon nanotubes and nanowires offer unique electronic and mechanical properties that make them extremely attractive for the task of biosensing. The structures and work principles of FETbiosensors based on carbon nanotubes/nanowires is discussed. Carbon nanotubes/silicon nanowire field-effect transistors have recently attracted great attention as promising tools in biosensor design because of their biocompatibility, size compatibility, ultrasensitivity, selectivity and label-free and real-time detection capabilities. In addition, interaction mechanisms between transducer elements of FET-biosensor (carbon nanotubes or nanowires) and target entities is also reviewed. Finally, applications of FET-type biosensors for measurement of different analytes is highlighted in this review. Proteins interaction, antibody–antigen reactions including prostate-specific antigen detection, DNA hybridization and enzymatic reactions involving glucose is shown.В этой статье мы описываем последние достижения в стремительно развивающейся области детектирования аналитов с использованием полевых транзисторов (ПТ на основе углеродных нанотрубок и нанопроводов. В статье описаны поведение и преимущества одномерных наноматериалов для использовании в биодатчиках. Среди одномерных нанометровых материалов углеродные нанотрубки и нанопроводы предлагают уникальные электронные и механические свойства, которые делают их чрезвычайно привлекательными для задач биодетектирования.Проанализированы структуры и принципы работы ПТ-биосенсоров на основе углеродных нанотрубок/нанопроводов. Полевые транзисторы на основе углеродных нанотрубок/кремниевых нанопроводов в последнее время привлекают к себе большое внимание как перспективные инструменты для проектирования биосенсоров из-за их биосовместимости, совместимости по размеру, ультрачувствительности, избирательности, а также возможностям без маркерного обнаружения в режиме реального времени. Кроме того, также проанализированы механизмы взаимодействия между элементами трансдьюсера ПТ-биосенсора (углеродными нанотрубками или нанопроводами) и объектами. В заключение,этом обзоре основное внимание отводиться применению биосенсоров на основе полевых транзисторов для измерения различных аналитов. Показаны реакции взаимодействия белков, реакция антитело-антиген, включая реакцию обнаружения простат-специфического антигена, ДНК-гибридизацию и ферментативные реакции с участием глюкозы

Recognitive hydrogel

Novel recognitive hydrogels and sensors are provided, as well as methods of fabricating and using such hydrogels and sensors. Such recognitive hydrogels may comprise a molecularly imprinted polymer having a binding cavity specific for a triggering molecule and a conductive polymer associated with the molecularly imprinted polymer. Such sensors may comprise the recognitive hydrogels and an impedance sensing component. Such methods may comprise providing a triggering molecule, providing a sensor comprising a molecularly imprinted polymer having a binding cavity specific for the triggering molecule, a conductive polymer associated with the molecularly imprinted polymer, and an impedance sensing component, introducing the triggering molecule into the sensor, and detecting a change in impedance of the recognitive hydrogel with the impedance sensing component.Board of Regents, University of Texas Syste

Interactions between Ions and Lysenin Nanochannels and their Potential Applications as Biosensors

Lysenin is classified as a pore-forming toxin protein that is isolated from the earthworm Eisenia fetida and consists of 297 amino acids [1]. Lysenin inserts large conducting pores (3.0-4.7 nm in diameter) into artificial membranes (BLM) which include sphingomyelin. These pores (channels) are open and oriented upon insertion into the bilayer lipid membrane. Lysenin channels gate at positive voltages (voltage-induced gating), but not at negative voltages. Lysenin pores also exhibit activity modulation in response to changes in ionic strength and pH, indicating that electrostatic interaction is responsible for Lysenin conductance activities. In this line of inquiries, and by modulating Lysenin electrostatic interactions, it was hypothesized that the electrical properties of Lysenin pores (channels) could be influenced by multivalent ions. The macroscopic conductance of Lysenin channels was inhibited by addition of multivalent ions. The inhibition was concentration dependent and reversible by addition of chelating or precipitating agents. The ability of the examined multivalent ions to inhibit pore conductance depended on ionic charge and size. Taken together, these results indicate that the Lysenin channel has a binding site that is placed inside the channel and interacts electrostatically with multivalent ions resulting in a conductance response related to ionic number and size. The high sensitivity of Lysenin pores toward trivalent ions indicates that Lysenin channels could be used to develop novel biosensors for multivalent ion detection in environmental samples. The dynamic interaction of Lysenin with multivalent ions was modeled based on the conductivity of the bulk solution and the status of Lysenin channels. The purpose of the model was to provide a mechanistic understanding of Lysenin gating. Using the experimental data, an equilibrium rate constant of the interaction between Lysenin and each multivalent ion was estimated. Each rate constant was related to the binding affinity of each ion with the binding site

Protein sequencing strategy in nanotechnology by classical and quantum atomistic models

Il mio lavoro di ricerca ha avuto l’obiettivo di studiare le proprietà principali dell’interazione tra materiale biologico e superfici inorganiche. Per tale scopo è stato utilizzato uno approccio basato sulla teoria del funzionale densità (DFT), lo studio è stato svolto nell’ambito del calcolo ad alte prestazioni utilizzando un approccio quanto-meccanico da principi primi, in modo da poter descrivere al meglio le interazioni chimico-fisiche a livello molecolare e sub-molecolare. Il tutto è stato applicato in dispositivi di ultima generazione per sequenziamento di catene biologiche, basate sulla tecnologia a nano-poro; in questi sensori nano-strutturati vi è un analisi detta a singola-molecola, il tipo e i modi d’interazioni tra dispositivo e target d’analizzare sono fondamentali e determinano la variazione del nostro segnale in uscita. Il funzionamento è relativamente semplice: si applica agli estremi della superfice con il poro una differenza di potenziale, e si misura la variazione della corrente quando il foro è occupato; le dimensioni del poro fanno si che si possa analizzare una molecola alla volta. Il materiale scelto per la realizzazione di questi dispositivi è stato il grafene per le sue proprietà elettroniche e la sua geometria; le catene biologiche scelte sono sequenze di amminoacidi; questa scelta si basa sulla possibile evoluzione di questi dispositivi, finora utilizzati per il sequenziamento di DNA (commercializzato dalla Oxford Nanopores Technologies), e sull’importanza dell’identificazione della sequenza e della struttura delle proteine, visto la connessione a patologie neurodegenerative come Parkinson e Alzheimer. Più in dettaglio il mio lavoro di ricerca è partito da studi precedenti dove venivano analizzate filamenti di DNA con la traslazione di basi nucleiche in nano-pori biologici per il sequenziamento; si sono studiati i cambiamenti caratteristici di corrente quando il target si avvicina alla superficie o attraversava il poro in modo da ottenere un'analisi rapida a singola-molecola. Si è provato, così, ad applicare lo stesso principio su sequenze di peptidi, per la loro importanza a livello medico-scientifico, con nanostrutture allo stato solido, visti i vantaggi di quest'ultimi rispetto a quelli biologici (miglior rapporto segnale rumore e una vita media più lunga). Sono state effettuate simulazioni Ab-Initio per caratterizzare sia le proprietà elettroniche superficiali, osservando la densità degli stati (DOS), e sia l'effetto quantistico del tunneling degli elettroni al variare della molecola interagente con la superficie. Per fare ciò si è studiata la corrente elettronica trasversale al piano del poro, su un ribbon di grafene, correlando le variazioni della nube elettronica con la molecola target. Per raggiungere questi obiettivi abbiamo: • definito modelli atomistici di interazione tra amminoacidi e bordi di un nano-poro di grafene; • utilizzato simulazioni atomistiche/molecolari per ottimizzare la morfologia (grandezza) e struttura (forma) più adeguata del poro; • studiato il funzionamento elettronico del nano-poro in fase di traslocazione degli amminoacidi attraverso esso. In particolare ci si è concentrati sul calcolo della conduttività trasversale attraverso la metodologia della Non-Equilibrium Green Function (NEGF) e l'approccio Landauer-Buttiker La ricerca è stata articolata in due fasi: I Fase: Design del nano-poro di grafene Nonostante diversi nano-pori siano già studiati con tecniche sperimentali, l’approccio teorico-modellistico basato su simulazioni molecolari atomistiche della struttura del nano-poro ha reso possibile avere una rigorosa caratterizzazione fisica e chimica del sistema; questa caratterizzazione è diventata la base per il successivo processo di ottimizzazione del dispositivo (passando da un nano-poro a un nano-gap). Dal punto di vista teorico-computazionale, si è confrontato il comportamento, strutturale del passaggio all’interno del sensore di diversi amminoacidi e si è progettato un nano-gap adatto alla valutazione degli effetti di traslocazione. II Fase: Caratterizzazione del segnale Si è studiata la variazione del “segnale” ottenuto, per caratterizzarlo al meglio e abbassare il rapporto segnale rumore. Attraverso varie analisi di post-processing si è andata a vedere la corrente elettronica elastica ed anelastica e si è aggiunta l’analisi della corrente ionica con simulazioni di dinamica molecolare classica

Carbon Nanostructure-Based Field-Effect Transistors for Label-Free Chemical/Biological Sensors

Over the past decade, electrical detection of chemical and biological species using novel nanostructure-based devices has attracted significant attention for chemical, genomics, biomedical diagnostics, and drug discovery applications. The use of nanostructured devices in chemical/biological sensors in place of conventional sensing technologies has advantages of high sensitivity, low decreased energy consumption and potentially highly miniaturized integration. Owing to their particular structure, excellent electrical properties and high chemical stability, carbon nanotube and graphene based electrical devices have been widely developed for high performance label-free chemical/biological sensors. Here, we review the latest developments of carbon nanostructure-based transistor sensors in ultrasensitive detection of chemical/biological entities, such as poisonous gases, nucleic acids, proteins and cells

Biosensors in Fermentation Applications

Biosensing technology offers new analytic routes to the use and study of fermentations, taking advantage of the high selectivity and sensitivity of the bioactive elements it exploits. Various biosensors had been commercially available today; they provide fermentation processes with convenient, accurate, and cost-effective ways of monitoring for key biochemical parameters. In this chapter, the basic ideas and principles of biosensors, especially applications of the most popular biosensors related to fermentations were highlighted

Orbiting quarantine facility. The Antaeus report

A mission plan for the Orbiting Quarantine Facility (OQF) is presented. Coverage includes system overview, quarantine and protocol, the laboratory, support systems, cost analysis and possible additional uses of the OQF