Advanced Sensors for Real-Time Monitoring Applications

It is impossible to imagine the modern world without sensors, or without real-time information about almost everything—from local temperature to material composition and health parameters. We sense, measure, and process data and act accordingly all the time. In fact, real-time monitoring and information is key to a successful business, an assistant in life-saving decisions that healthcare professionals make, and a tool in research that could revolutionize the future. To ensure that sensors address the rapidly developing needs of various areas of our lives and activities, scientists, researchers, manufacturers, and end-users have established an efficient dialogue so that the newest technological achievements in all aspects of real-time sensing can be implemented for the benefit of the wider community. This book documents some of the results of such a dialogue and reports on advances in sensors and sensor systems for existing and emerging real-time monitoring applications

NanoSERS Microfluidics platform for rapid screening for infectious diseases

Early and accurate disease detection is critical for clinical diagnosis and ultimately determining patient outcomes. Point-of-care testing (POCT) platforms are needed in low- resource settings and also to help the decentralisation of healthcare centres. Immunoas- says using Surface-Enhanced Raman Spectroscopy (SERS) are especially interesting for their increased sensitivity and specificity. Additionally, SERS can be easily translated into POCT formats with microfluidics. In this work, a sensitive, selective, capable of multiplexing, and reusable SERS-based biosensor was developed. The SERS immunoas- say relies on a sandwich format, whereby a capture platform and SERS immunotags can capture and detect a specific antigen, respectively. The SERS immunotags consisted of gold nanostars, allowing exceptionally intense SERS signals from attached Raman re- porters, and the covalent attachment of antibodies provided a stable antigen-antibody binding activity. As a capture platform, a regenerated cellulose-based hydrogel provided a robust design and the added advantage of environmental friendliness. Besides being a transparent material with low background fluorescence and Raman signal, its high-water retention capacity was particularly suited for preserving the high activity of covalently bound antibodies, improving the assay time-stability. This SERS-based immunoassay was then integrated into a microfluidic device, allowing high-throughput sample screening allied with the high sensitivity and multiplexing features of the developed assay. The de- vice was fabricated in less than 30 minutes by exploring direct patterning on shrinkable polystyrene sheets for the construction of adaptable complex three-dimensional microflu- idic chips. Finally, to validate the microfluidic system, Plasmodium falciparum infected red blood cell culture samples were tested for malaria biomarker detection. The discrimi- nation of SERS immunotags signals from the background was made through the direct classical least squares method. As a result, better data fitting was achieved, compared to the commonly used peak integral method. Considering these features, the proposed SERS-based immunoassay notably improved the detection limits of traditional enzyme- linked immunosorbent assay approaches. Its performance was better or comparable to existing SERS-based immunosensors. Moreover, this approach successfully overcame the main challenges for application at POCT, including increasing reproducibility, sensitivity, and specificity. Hence, the microfluidic SERS system represents a powerful technology which can contribute to early diagnosis of infectious diseases, a decisive step towards lowering their still substantial burden on health systems worldwide.A detecção precoce e precisa de doenças é fundamental para o diagnóstico clínico de- terminando frequentemente o prognóstico do paciente. Desta forma, plataformas de teste de rastreio (conhecidos pelo acrónimo de POCT) são extremamente necessárias, não só em locais com poucos recursos, mas também para ajudar à descentralização dos cuidados de saúde. Os ensaios imunológicos que utilizam a espectroscopia de Raman aumentada pela superfície (conhecida pelo acrónimo de SERS) são particularmente interessantes pela sua elevada sensibilidade. Além disso, os ensaios em SERS podem ser facilmente convertidos para formatos POCT quando combinados com microfluídica. Este trabalho consistiu no desenvolvimento de um biosensor sensível, selectivo, capaz de múltipla detecção e reuti- lizável baseado no fenómeno de SERS. O ensaio imunológico em SERS foi realizado num formato em sanduíche onde um antigénio específico é apreendido por uma plataforma de captura e reconhecido por imunosondas activas em SERS. Estas sondas consistem em nanopartículas de ouro em forma de estrela, que proporcionam um sinal de SERS intenso proveniente das moléculas repórter de Raman ligadas às nanopartículas. As sondas ad- quirem a especificidade necessária para o antigénio de anticorpos a elas ligados de forma covalente, e, por conseguinte, permitem uma ligação estável antigénio-anticorpo. O hidro- gel regenerado à base de celulose forneceu uma plataforma de captura de design robusto e ecológico. Além de ser um material transparente com baixa fluorescência e, portanto, de baixa interferência no sinal de Raman, é um material com uma elevada capacidade de retenção de água tornando-o particularmente adequado para preservar a actividade dos anticorpos ligados covalentemente. Deste modo, o hidrogel proporciona uma plataforma de captura estável ao longo do tempo. O immunoensaio baseado em SERS desenvolvido foi posteriormente integrado num dispositivo de microfluídica, permitindo analisar um grande número de amostras sendo simultaneamente sensível e passível para aplicações de análise de múltiplos antigénios. O dispositivo foi fabricado em menos de 30 minu- tos devido à padronização directa em folhas de poliestireno contrácteis possibilitando a construção tridimensional de um dispositivo de microfluídica. Finalmente, para validar o sistema de microfluídica, amostras de cultura de eritrócitos infectados com Plasmodium falciparum foram testadas para detecção de biomarcadores de malária. A discriminação dos sinais das immunosondas activas em SERS, relativamente a sinais interferentes, foi feita através do método clássico de quadrados mínimos. Como resultado, foi conseguido um melhor ajuste de dados em comparação com o método de cálculo do integral das áreas das bandas habitualmente utilizado. Assim, o ensaio imunológico baseado em SERS proposto neste trabalho permitiu obter um limite de detecção mais baixo do que o obtido pelas abordagens tradicionais como o ensaio de imunoabsorção enzimática (conhecido pelo acrónimo de ELISA), além de exibir um desempenho melhor ou comparável a ou- tros sensores baseados em SERS já existentes na literatura. Adicionalmente, o sistema desenvolvido neste trabalho permite ultrapassar desafios que impedem a utilização deste tipo de sensores em locais de poucos recursos, apresentando valores elevados de repro- dutibilidade, sensibilidade e especificidade. Por conseguinte, um sistema que combina SERS e microfluídica representa uma tecnologia potencialmente importante na detecção precoce, na esperança de que, num futuro próximo, as consequências das doenças infecci- osas que ainda impõem um fardo substancial ao sistema de saúde a nível mundial, sejam minoradas

Raman Spectroscopy and Surface Plasmon Resonance as Photonic Tools for Biopharmaceutical Applications

Biophotonics is an emerging area of scientific research that uses light of photons to probe biological specimens, such as tissues, cells and molecules. The field of biophotonics is broad and considerably multidisciplinary. Therefore the prerequisite for understanding biophotonics is the capability to integrate the fundamental knowledge of the physics of light with perspectives of engineering of devices and instruments used to generate, modify, and manipulate light. Also, the fundamentals of biology and medicine are essential particularly comprehension of the biochemical and cellular phenomena that occur in living systems, and how such phenomena can be scaled up to concern the physiology of organisms, for example humans. Biological pathways and processes differ in the healthy and diseased state, and that is why it is essential to develop understanding of pathophysiology and various states of disease such as cancer, neurodegenerative disease or infectious states. Consequently, solid insights into the functions of medical treatments, including biopharmaceutics, are needed. Raman and surface plasmon resonance (SPR) are both light-based technologies enabling label-free measurements with high sensitivity. The primary aim of this Thesis was to tackle the emerging hardships encountered in the fundamental biopharmaceutical research, clinical settings, or in the pharmaceutical industry by introducing applications and data analysis methods based on the cutting edge Raman and SPR technologies. These techniques represent the biophotonic cornerstones as tools for biopharmaceutical applications throughout this Thesis. The scope of this Thesis was essentially broad. First, small drug molecules were investigated with state-of-the-art time-gated Raman technology, showing that the interfering photoluminescent backgrounds can be effectively suppressed thus improving the acquired Raman data significantly. Additionally, EVs were studied with laser tweezers Raman spectroscopy (LTRS) as larger scale analytes and representatives of a highly interesting topic in the current nanomedical field. When Raman data from several different types of single EVs was examined using sophisticated data analysis, distinct subpopulations were observed, and the differences could be related to the biochemical compositions of the vesicle membranes. For the first time, the study showed the importance of measuring single EVs instead of a pool of vesicles. Multi-parametric SPR (MP-SPR) technology was harnessed to develop applications and data analysis methods for small and larger scale analytes. Hence, a new small drug molecule, spin-labeled fluorene (SLF), was investigated in the context of Alzheimer s disease (AD) particularly its potential to interfere with the detrimental amyloid peptide aggregation processes. The developed bio-functional in vitro platform in combination with rigorous data analysis and computational simulations demonstrated the capabilities of SLF when it was employed in various biomimetic aggregation schemes. Moreover, liposomes were examined with the MP-SPR as larger scale nanomedical particles for the purposes of safe and effective nanocarrier development. The administration of a liposomal nanocarrier into the blood circulation was mimicked in the designed bionanophotonic in vitro schemes. Undiluted serum was made to interact with immobilized model liposomes in dynamic flow conditions. The findings revealed that the variation in surface chemistries of the liposomes plays a role when serum essentially immune system components are interacting with the liposomes. In particular, distinct soft and hard protein coronas were observed and characterized during the interactions. Collectively, the results and findings in this Thesis underline the broad potential of biophotonics for biopharmaceutical applications. The technical improvements in instrumentation, and creativity in the application and data analysis development make the future of biophotonics bright.Biofotoniikka on kasvava tieteenala, jossa valon fotoneja käytetään biologisten kohteiden tutkimiseen. Esimerkkeinä kudokset, solut ja molekyylit. Biofotoniikka tieteenalana on huomattavan poikkitieteellinen. Valon tuottamiseksi ja muokkaamiseksi tarvitaan perustavanlaatuista tietoa fysiikasta sekä teknisiä taitoja laitteiden suunnittelemiseksi. Lisäksi biologian, ja lääketieteen perusteet ovat olennainen osa biofotoniikkaa. Erityisen tärkeää on ymmärrys biofysiikasta ja -kemiasta sekä molekyyli- ja solutason ilmiöistä, jotka tapahtuvat elävissä systeemeissä. Tämän väitöstyön tavoitteena oli kehittää biofotonisia tekniikoita, menetelmiä ja data-analytiikkaa nykyisen biofarmaseuttisen tutkimuksen haasteisiin. Olemassa olevien in vitro menetelmien, eli esimerkiksi koeputkessa tai maljassa tehtävien biologisten mallisysteemien ongelmana on usein se, että tulosten siirrettävyys kliinisiin tutkimuksiin ja lopullisiksi lääkevalmisteiksi ei ole suoraviivaista. Esimerkiksi leima-aineiden, kuten fluoresoivien tai radioaktiivisten molekyylien lisääminen tutkittaviin kohteisiin saattaa muuttaa niiden fysikaalista ja kemiallista käyttäytymistä elävässä ympäristössä. Raman-spektroskopia ja pintaplasmoniresonanssi ovat molemmat valoon perustuvia teknologioita, joilla mittauksia voidaan suorittaa ilman leima-aineita ja korkealla herkkyydellä. Molemmista teknologioista käytettiin kehityksen kärjessä olevia instrumentteja. Ne edustivat tässä työssä biofotonisia tekniikoita, joita täydennettiin perinteisillä tutkimusmetodeilla. Väitöstyössä tutkittiin aluksi pienlääkeaineita kiinteässä olomuodossaan Raman-spektroskopian avulla. Raman-spektroskopialla voidaan mitata erittäin tarkasti tutkittavien molekyylien kemiallinen rakenne. Tavallisesti Raman-tutkimusten ongelmana on kuitenkin voimakas fotoluminesenssi, joka tuottaa häiritsevän taustasignaalin ja haittaa Raman-spektrien tulkintaa. Uudella aika-portti Raman-tekniikalla pystyttiin erottelemaan Raman- ja fotoluminesenssisignaalit tehokkaasti. Tämä mahdollisti vaikeasti mitattavien lääkeaineiden Raman-spektrien mittaamisen ja tarkemman karakterisoinnin. Tutkimusten toisessa vaiheessa mitattiin ensimmäistä kertaa yksittäisiä ekstrasellulaarivesikkeleitä. Ekstrasellulaarivesikkelit ovat solujen tuottamia, kalvorakenteisia nanorakenteita, joiden läpimitta on noin 50 1000 nm. Niiden hyödyntäminen syöpädiagnostiikassa ja nanolääketieteellisinä lääkekantajina on kasvavan kiinnostuksen kohteena, mutta tutkimuksia rajoittaa vesikkeleiden biokemiallinen monimuotoisuus ja pieni koko. Mittaukset suoritettiin toisella uudentyyppisellä Raman-tekniikalla, laser-ansalla. Terveiden solujen ja syöpäsolujen tuottamien vesikkeleiden biokemiallista koostumusta arvioitiin kehitetyn monimuuttuja-analyysin keinoin ja havaittiin, että merkittävimmät erot vesikkeleiden välillä liittyivät niiden pintarakenteiden erilaisuuteen. Saaduilla tuloksilla on merkitystä vesikkeleiden funktioiden ymmärtämisessä ja niiden hyödyntämisessä nanolääketieteellisissä applikaatioissa. Väitöstutkimuksen kahdessa muussa osiossa kehitettiin pintaplasmoniresonanssiin pohjautuvia menetelmiä sekä data-analyysiä niin ikään pienlääkemolekyylien ja nanolääketieteellisten kohteiden tutkimukseen. Käytetty moderni pintaplasmoniresonanssitekniikka mahdollisti perinteisestä poikkeavan, perusteellisemman data-analyysin toteuttamisen. Ensin tarkasteltiin Alzheimerin taudin hoitoon kehitettyä uutta lääkemolekyyliä, jonka oli todettu hidastavan haitallista amyloid-peptidien yhteenliittymistä. Tutkimuksissa kehitetty bio-funktionaalinen in vitro alusta yhdessä tietokonesimulaatioiden kanssa osoitti, että tutkittu molekyyli vähensi selvästi amyloid-aggregaatiota. Analyysillä pystyttiin myös karakterisoimaan molekyylin interaktio-ominaisuuksia. Liposomit edustivat väitöstutkimuksen viimeisessä osuudessa nanolääketieteellisiä partikkeleita, joiden ominaisuuksia tutkittiin pintaplasmoniresonanssin avulla. Tällä hetkellä ainoat ihmiskäyttöön hyväksytyt nanolääkekantajat perustuvat liposomeihin. Kehitetyllä bionanofotonisella in vitro -alustalla matkittiin liposomikantajan annostelua verenkiertoon. Laimentamattoman seerumin annettiin vuorovaikuttaa sensoripinnalle immobilisoitujen liposomien kanssa dynaamisissa virtausolosuhteissa. Tulokset osoittivat, että liposomien pintakemialla on todennäköisesti vahva vaikutus siihen, miten seerumin komponentit, erityisesti immuunijärjestelmä, reagoivat annosteltuun liposomikantajaan. Havainnoilla on potentiaalista merkitystä turvallisten ja tehokkaiden lääkekantajien kehitystyössä. Yhteenvetona voidaan todeta, että biofotoniikkaa voidaan hyödyntää hyvin luovalla tavalla biofarmaseuttisiin applikaatioihin. Väitöstutkimuksen tulokset osoittavat, että kehitetyillä alustoilla ja data-analyysimenetelmillä on mahdollista parantaa nykyistä pienlääkekehitystä sekä nanolääketieteellistä tutkimusta

Ion and Molecule Transport in Membrane Systems

Membranes play an enormous role in our life. Biological cell membranes control the fluxes of substances in and out of cells. Artificial membranes are widely used in numerous applications including “green” separation processes in chemistry, agroindustry, biology, medicine; they are used as well in energy generation from renewable sources. They largely mimic the structure and functions of biological membranes. The similarity in the structure leads to the similarity in the properties and the approaches to study the laws governing the behavior of both biological and artificial membranes. In this book, some physico-chemical and chemico-physical aspects of the structure and behavior of biological and artificial membranes are investigated

Annual report 2009 // Institute of Radiochemistry

[no abstract available

49th Rocky Mountain Conference on Analytical Chemistry

Final program, abstracts, and information about the 49th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Breckenridge, Colorado, July 22-26, 2007