Lab-on-a-chip platforms for pathogen analysis

Infectious diseases caused by pathogenic microorganisms are a big burden in developed and developing countries. The emergence and rapid global spread of virus and antimicrobial resistant bacteria is a significant threat to patients, healthcare systems and the economy of countries. Early pathogen detection is often hampered by low concentrations present in complex matrices such as food and body fluids.Microfluidic technologies offer new and improved approaches for detection of pathogens on the microscale. Here, two microfluidic platforms for pathogen sorting and molecular identification were investigated: (1) inertial focusing and (2) microscale immiscible filtration. Inertial focusing in two serpentine channel designs etched in glass at different depths was evaluated with different microparticles, bacteria and blood. The shallow design allowed 2.2-fold concentration of Escherichia coli O157 cells, whereas the deep design accomplished recovery of 54% E. coli O157 depleted from 97% red blood cells in 0.81% haematocrit at flowrates of 0.7 mL min-1.A lab-on-a-chip platform based on microscale immiscible filtration was investigated for capture and detection of nucleic acids and bacteria. For nucleic acids, oligo (dT) functionalised magnetic beads or silica paramagnetic particles in GuHCl were used to capture genomic RNA from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and genomic DNA from Neisseria gonorrhoeae, respectively. On-chip amplification and detection were performed via colorimetric loop-mediated isothermal amplification (LAMP). Results showed sensitive and specific detection of targeted nucleic acids (470 RNA copies mL-1 and 5 × 104 DNA copies mL-1) with no cross-reactivity to other RNAs and DNAs tested. The whole workflow was integrated in a single device and time from sample-in to answer-out was within 1h. The platform only required power for a heat source and showed potential for point of care diagnostics in resource-limited settings. For bacteria detection, anti-E. coli O157 functionalised magnetic beads were used to capture cells with > 90% efficiency and on-chip fluorescence in situ hybridisation and a staining assay were explored for bacteria identification.A wide variety of microfluidic approaches for pathogen analysis have been devised in the literature with different advantages and drawbacks. Careful evaluation based on their purpose, integrated steps and end user is critical. Input from stakeholders right from the start of a project and throughout is vital to success. The platforms investigated herein have potential for applications such as sample preparation, pathogen concentration and specific molecular detection of E. coli O157, N. gonorrhoeae DNA, and SARS-CoV-2 RNA. With further development and clinical validation, the widespread use of these systems could facilitate early diagnosis of infectious diseases, allowing timely management of outbreaks and treatment and slowing the incidence of antimicrobial resistance

Mobile Diagnosis 2.0

Mobile sensing and diagnostic capabilities are becoming extremely important for a wide range of emerging applications and fields spanning mobile health, telemedicine, point-of-care diagnostics, global health, field medicine, democratization of sensing and diagnostic tools, environmental monitoring, and citizen science, among many others. The importance of low-cost mobile technologies has been underlined during this current COVID-19 pandemic, particularly for applications such as the detection of pathogens, including bacteria and viruses, as well as for prediction and management of different diseases and disorders. This book focuses on some of these application areas and provides a timely summary of cutting-edge results and emerging technologies in these interdisciplinary fields

Biomedical Applications of Protein Films and Polymeric Nanomaterials

Biomaterials are widely applied for the diagnosis and treatment of numerous diseases. In addition to fulfilling specific biological functions, biomaterials must also be non-toxic, biocompatible, and sterilizable to be regarded as safe-for-use. Polymers are excellent candidates for fabricating functional biomaterials due to their wide availability and varied properties and may be natural or synthetic. Polymer precursors are fabricated into coatings, foams, scaffolds, gels, composites, and nanomaterials for several biomedical applications. This dissertation focuses on two types of polymeric biomaterials – protein-based materials and synthetic polymeric nanoparticles. Proteins are biopolymers that naturally occur with a variety of structural and functional properties. However, the fabrication of protein-based materials is challenging due to their aqueous and mechanical instability. In this work we highlighted the development of an additive-free, thermal treatment approach that relies on heat-curing protein films in fluorous media (fluorous-curing). In doing so, we are able to minimize protein denaturation and retain surface properties. Charged protein films were utilized to prepare antimicrobial coatings and size-sorting devices. We also demonstrated the utility of fluorous-curing to enhance mechanical and enzymatic stability of collagen films with minimal denaturation. In the latter part of this work, we utilized ultrasound treatment to enhance the activity of biomaterials. Ultrasound is gaining interest as a tool used in combination with biomaterials for applications such as enhanced penetration of therapeutics into tissue, regulating drug release through ultrasound-responsive scaffolds, and sonodynamic therapy. However, these developments are limited and delayed due to the lack of effective in vitro models that prevent uncontrolled cell lysis during ultrasound. We developed 2D and 3D cell cultures for ultrasound treatment using collagen-based materials. We hypothesized that collagen would act as a support for the cells and absorb the energy exerted by ultrasound, thereby protecting the cells. We then utilized ultrasound in combination with antimicrobial polymeric nanomaterials for the synergistic eradication of bacterial biofilms. Antimicrobial polymer nanoparticles are an alternative to traditional antibiotics that prevent development of drug resistance. However, longer incubation durations and higher concentrations are required to allow for penetration into the bacterial biofilms which results in toxicity to mammalian cells. Ultrasound enhances the penetration of these nanoparticles into the biofilm EPS thereby reducing the incubation time and enhancing antimicrobial activity, with minimal toxicity to mammalian cells. Overall, this dissertation discusses significant developments in polymeric materials for varied potential applications as diagnostic sensors, antimicrobial materials, wound-healing, tissue engineering, and drug delivery applications

A facile blow spinning technique for green cellulose acetate/polystyrene composite separator for flexible energy storage devices

projects LA/P/0037/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication – i3N. This work was also supported by ERC-CoG-2014. The authors would also like to thank João Lopes for his contribution with the home-made mechanical abrasion setup. Publisher Copyright: © 2023 The Author(s)The search of sustainable gadgets, such as the portable electronics and wearables, have sparked the need for more sustainable and environment friendly constituent elements (e.g., electrode materials, separators, and green electrolytes) and low-cost scalable fabrication techniques. Herein, a facile and scalable blow spinning technique is proposed for the synthesis of a cellulose-based separator for flexible energy storage devices. A cellulose acetate and polystyrene (CA:PS) based composite separator is synthesized for the first time for flexible supercapacitors by exploiting the blow spinning technique. Different combinations of CA:PS were synthesized, and electrochemical performances of the devices were evaluated. A sweat simulation solution is used as green electrolyte for the development of symmetrical carbon yarn-based supercapacitors. The influence on the device performances of pristine carbon yarn, activated carbon yarns and PEDOT functionalized carbon yarns, electrodes were compared. Specific capacitances of 2.8 Fg−1 and 33 Fg−1 were obtained for pristine carbon and PEDOT functionalized carbon fibers respectively. The fabricated devices exploiting the composite separator exhibited good washing stability up to 30 cycles and capacitance retention of 95% up to 1000 charge/discharge cycles.publishersversionpublishe

Microfluidics on porous substrates mediated by capillarity-driven transport

Microfluidic systems on porous substrates, including paper-based analytical platforms, have attracted significant attention recently, primarily attributed to their diversified applications, ranging from bioanalytical devices for healthcare technologies to green energy generation and flexible electronics. In this short Review, we attempt to provide a concise overview about the fundamental premises of functionalities of these devices, starting from the understanding of flow in single one-dimensional conduit. This can be extended to more-complex systems, where an intrinsic capillary action offers the necessary provisions for continuous maintenance of heterogeneous flow over multiple spatiotemporal scales, which essentially facilitates the needs of specific applications. We discuss a few specific applications as demonstrative examples that are solely triggered by the intrinsic capillary action of the porous media. These specific examples delineate the fact that flexible architecture of the devices, in combination with the inherent capillary-driven phenomena, makes it suitable to meet the desired user-specific demands at affordable costs, rendering them immensely suitable for the low-resource-settings environment

Measurements and comparison of primary biological aerosol above and below a tropical forest canopy using a dual channel fluorescence spectrometer

Original article can be found at: http://www.atmos-chem-phys.net/10/issue10.html Copyright - the authors. Authors grant any third party the right to use the article freely as long as its original authors and citation details are identified. The article and any associated published material is distributed under the Creative Commons Attribution 3.0 License.Aerosol particle size distributions were measured below and above a tropical rainforest canopy in Borneo, Malaysia, in June/July 2008 using the WIBS-3: a single particle dual channel fluorescence spectrometer. Material in the size range 0.8–20 μm was characterized according to optical equivalent diameter (DP), morphology and fluorescence at 310–400 nm and 400–600 nm following excitation at 280 nm and 370 nm respectively. Particles fluorescent after both excitations are likely to be fluorescent primary biological aerosol particles (FBAP). Measured FBAP number concentration (NFBAP) at both sites exhibited clear diurnal cycles. The largest variability was observed in the understorey, where NFBAP reached a minimum of 50–100 L−1 in late morning. In mid afternoon it exhibited strong transient fluctuations as large as 4000 L−1 that were followed by sustained concentrations of 1000–2500 L−1 that reduced steadily between midnight and sunrise. Above the canopy FBAP number ranged from 50–100 L−1 during the daytime to 200–400 L−1 at night but did not exhibit the transient enhancements seen in the understorey. The strong FBAP fluctuations were attributed to the release of fungal spores below the canopy and appeared to be linked to elevated relative humidity. The mean FBAP number fraction in the size range 0.8 μm<DP<20 μm was 55% in the understorey and 28% above canopy. A size mode at 2 μm<DP<4 μm appears at both sites and is primarily FBAP, which dominated the coarse (DP≥2.5 μm) number concentration at both sites, accounting for 75% in the understorey and 57% above the canopy. In contrast, the concentration of non-fluorescent particles (NNON) at both sites was typically 200–500 L−1, the majority of which occupied a size mode at 0.8<DP<1.5 μm. Enhanced understorey NNON was observed daily in mid-afternoon and also at midday on three occasions: the former coincided with the FBAP enhancements and measured approximately 10% of their magnitude; the latter occurred independently of the NFBAP diurnal cycle and comprised particles smaller than 2 μm. Particle diameter of 3–5 μm is consistent with smaller fungal spores, though absolute identification of biological species is not possible with the UV-LIF technique. Based on the measured FBAP and non-fluorescent particle abundances and their observed recovery times following rain showers, FBAP originated beneath the canopy while the non-fluorescent material was transported from further away. It is concluded that these separate sources contributed the majority of the aerosol measured by the WIBS-3 at both sites.Peer reviewe

Nanoarchitectonics of Nanocellulose-Carbon Nanotube Composites : From Dispersion to Functional Structures

Väitöskirjatutkimuksessa pyrittiin selvittämään parametrejä ja ilmiöitä, mitkä vaikuttavat nanoselluloosa-hiilinanoputki (NC-CNT) komposiittien ominaisuuksiin mm. sähkönjohtavuuteen. Nanoselluloosa tarjoaa komposiittirakenteelle ympäristöystävällisen, edullisen, erittäin lujan, mittapysyvän, sulamattoman, myrkyttömän ei metallisen matriisin tai se voi toimia kantajana muille nanomateriaaleille, kuten hiilinanoputkille. Valmistettavan NFC-CNT komposiitin ominaisuudet ovat kuitenkin vahvasti riippuvaisia CNT-dispersion laadusta, nanoputkien pituus-leveyssuhteesta disperkointiprosessin jälkeen ja matriisin lujuudesta, unohtamatta hiilinanoputkien ja nanoselluloosan matriisin keskinäisiä vuorovaikutuksia. Kun tarkastellaan tieteellisessä kirjallisuudessa raportoitujen selluloosa-CNT-komposiittien sähkönjohtavuusarvoja, voidaan todeta, että komposiittirakenteissa sähkövirran liikkuminen on vajavaista. Ensimmäiseksi, sähkövirtaa johtava materiaali ei välttämättä muodosta tehokasta perkolaatioverkostoa, ja toiseksi, disperkointimenetelmä johtaa komposiittirakenteeseen, joka sisältää johtavan materiaalin muodostamia agglomeraatteja. Tärkein syy voi silti olla, että eristävä matriisimateriaali estää komposiittirakenteessa elektronien liikkeen kokonaan tai osittain. Näitä muuttujia ei tutkita perusteellisesti nykyisessä tieteellisessä kirjallisuudessa ja siksi niitä käsitellään tässä väitöskirjatutkimuksessa. Tutkimuksen lähestymistavaksi on valittu nanoarkkitehtoniikka-konsepti, joka hyödyntää useita tutkimusaloja ja teknologioita, jotta hybridi- ja komposiittimateriaalisysteemien luominen mahdollistuu. Nanoarkkitehtoniikka yhdistää poikkitieteellisesti materiaalioppia, nanoteknologiaa ja kemiaa, jotta nanomateriaalien kanssa työskenneltäessä ilmenevät haasteet voidaan selättää. Tutkimus on jaettu osiin tutkimalla kaksi-, kolme- ja neljäkomponenttisysteemejä, ja tunnistamalla mitkä parametrit vaikuttavat nanomateriaalien keskinäisiin vuorovaikutuksiin sekä miten valmistettavan nanokomposiitin ominaisuuksia voidaan edelleen muokata valmistuksen jälkeenkin. Läpi koko väitöskirjatutkimuksen on noudatettu ohjenuoraa, jonka tavoitteena on käyttää ainoastaan minimimäärä materiaaleja, kemikaaleja ja energiaa komposiittien valmistuksessa. Keskeisimpiin tuloksiin lukeutuu nanofibrilloidun selluloosan (NFC)-hiilinanoputkikomposiitti-kalvojen hyvä sähkönjohtavuus, joka on korkein kirjallisuudessa ilmoitettu verrattain vähäisellä 16,7 p-% CNT-pitoisuudella. Tämä tulos saavutettiin varioimalla sekä CNT että NFC-CNT dispersion valmistusvaiheessa erityyppisten surfaktanttien pitoisuutta ja tarkastelemalla sonikaatioenergian vaikutusta, niin CNT dispersion laatuun kuin NFC-CNT dispersiosta valmistettujen kalvomuotoisten komposiittien sähkönjohtavuuteen. Komposiittikalvojen prosessoinnissa käytettiin keskipakovoimaa hyödyntävää valmistustekniikkaa ja muodostuneen NFC-CNT komposiitin havaittiin luovan kalvon paksuussuuntaan homogeenisen ja tiiviisti pakkautuneen rakenteen. Suorittamalla valmistetuille komposiittikalvoille jatkokäsittely, missä poistettiin nanomateriaalien rajapinnoilta disperkoinnissa apuna käytetty surfaktantti, saatiin NFC-CNT komposiitin sähkönjohtavuutta edelleen kasvatettua. Lisäksi väitöskirjatutkimuksessa todennetaan ensimmäistä kertaa, että katinoitua nanoselluloosaa (c-CNF) voidaan käyttää hiilinanoputkien disperkoimiseen, jolloin muodostuu homogeeninen ja stabiili c-CNF-CNT dispersio. Merkittäviin tuloksiin voidaan myös lukea havainto nanoselluloosan kokojakaumasta suhteessa hiilinanoputkiin ja sen vaikutuksista sähkönjohtavuusominaisuuksiin, ja lisäksi nanoselluloosan käyttö hiilinanoputkien kantajana esim. vaahtorainauksessa. Väitöskirjatutkimuksen aikana tehtyjen huomioiden ja tulosten pohjalta asetettiin sekä toteutettiin neljäkomponenttisysteemin valmistusprosessin kunnianhimoinen tavoite. Tavoitteena oli valita käytettävä surfaktantti niin, että se toimii sekä stabiilin homogeenisen NFC-CNT dispersion muodostuksessa kuin myös vaahtorainauksen vaahdonmuodostaja. Tällöin käytettävien kemikaalien määrä vähenee selvästi, kun niillä on useampi rooli tasamaisten sekä 3D-komposiittirakenteen valmistusprosessissa. Tämä väitöskirjatutkimus asettaa perustan NC-CNT-komposiittirakenteiden tulevalle tutkimukselle. Tutkimuksessa havaittiin rakenteen ja funktionaalisuuden välinen korrelaatio, että erityisesti selluloosan kokojakaumalla on ratkaiseva rooli optimoidun johtavuuden luomisessa rajoitetulla määrällä hiilinanoputkia, säilyttäen samalla johtavan materiaalin vaaditut mekaaniset lujuusominaisuudet. Oletettavasti vielä korkeammat sähkönjohtavuusarvot voidaan saavuttaa, kun nanoselluloosan pituus-leveyssuhde on optimoitu vastaamaan CNT:n kokoa siten, että NC-pinnat pinnoittuvat hiilinanoputkilla kattavasti muodostaen sähköjohtavan perkolaatioverkon. Huomioitavaa on kuitenkin, että tutkimus keskittyi saavuttamaan erinomaiset sähköiset ominaisuudet NFC-CNT komposiittimateriaalille. Jos taas halutaan optimoida esimerkiksi mekaaniset ominaisuudet, voi nanomateriaalien disperkoimiseen tarvittava energia ja materiaalien keskinäiset kokosuhteet poiketa toisistaan huomattavasti. Tavanomaisesta väitöskirjatutkimuksesta poiketen tutkimuksessa saavutetut tulokset on konkretisoitu, kun niiden pohjalta on valmistettu kahdella eri prosessilla toiminnalliset lämmityselementit. Ensimmäinen lämmityselementti "Salmiakki" on ollut esillä useissa seminaareissa ja messuilla medianäkyvyyden lisäksi. Toinen lämmityselementti pääsi tutkimusmaailmasta lähemmäksi kansaa, kun se implementoitiin osaksi Liune-liukuvaa väliovea ja esiteltiin Lohjan Asuntomessujen 2021 Pyörre -messutalossa.The dissertation research seeks to identify parameters and phenomena that affect the properties of nanocellulose carbon nanotube (NC-CNT) composites, among others, on electrical conductivity. Nanocellulose provides the composite structure with an environmentally friendly, inexpensive, high-strength, dimensional, indigestible, non- toxic non-metallic matrix or it can serve as a carrier for other nanomaterials such as carbon nanotubes. The properties of the NC-CNT composite being produced are strongly dependent on the quality of CNT dispersion, the length—width ratio of the nanotubes after the dispersion process, and the strength of the matrix, not forgetting the interactions between carbon nanotubes and nanocellulose matrix. When comparing electrical conductivities of cellulose-CNT composites reported in current scientific literature, it can be stated that several composite structures have an inefficient flow of current. First, conducting particles may not form an efficient percolation network, and second, inadequate distribution procedure results in a composite structure containing agglomerates of conductive particles. The main reason might still be that, in the formed composite structure, insulating matrix material is obstructing the flow of the electrons. These attributes are not thoroughly researched in current scientific literature and are addressed in this thesis. The nanoarchitectonics concept, which utilizes several research fields and technologies to enable the creation of hybrid and composite material systems, has been chosen as an approach to the research. Nanoarchitectonics combines materials science, nanotechnology, and chemistry to overcome the challenges that arise when working with nanomaterials. The research is divided into sections by examining two-, three-, and four-component systems, and identifying which parameters affect interactions between nanomaterials, as well as how the properties of nanocomposites can be further modified even after manufacturing. Throughout the entire dissertation study, a guideline aiming to use only a minimum amount of materials, chemicals, and energy in the manufacture of composites has been followed. The main results include exemplary electrical conductivity of nano fibrillated cellulose (NFC) carbon nanotube composite films, the highest reported in the literature at a comparatively low 16.7 w-% CNT concentration. This result was achieved by varying the concentration of different types of surfactants and looking at the effect of sonication energy, both on CNT dispersion quality and on the electrical conductivity of the film form composites made from NFC-CNT dispersion. In the processing of composite films, a manufacturing technique utilizing centrifugal force was used and the formed NFC-CNT composite was found to create a homogeneous and tightly compressed structure in the thickness direction of the film. Post processing of the prepared composite films, where surfactant assisting dispersing of nanomaterials was removed from interfaces, the electrical conductivity of the NFC-CNT composite was further increased. In addition, the thesis study verified for the first time that cationic cellulose nanofibers (c-CNFs) can be used to disperse carbon nanotubes to form homogeneous and stable c-CNF-CNT dispersion. Notable results can also be attributed to the observation of the size distribution of nanocellulose relative to carbon nanotubes and its effects on electrical conductivity properties, and additionally the use of nanocellulose as a carrier of carbon nanotubes, e.g., in foam forming. Based on the observations and results made during the dissertation study, the ambitious goal of the four component system manufacturing process was set and realized. Goal was to select the surfactant so that it would function both in the formation of stable homogeneous NFC-CNT dispersion and as a foam former in formation process. In this case, the amount of chemicals used is clearly reduced when they play multiple roles in the manufacturing process of flat and 3D composite structures. This thesis research sets the foundation for future research of NC-CNT composite structures. Correlation between structure and functions was observed in this thesis, that especially size distribution of cellulose plays a crucial role in creating optimized conductivity with a limited amount of CNTs, while retaining the required mechanical strength characteristics of the conductive material. It can be expected that even higher electrical conductivity values can be achieved when nanocellulose aspect ratio is optimized to match the size of the CNTs so that NC surfaces are comprehensively coated with carbon nanotubes to form an electrically conductive percolation network. However, it should be noted that the research focused on achieving excellent electrical properties for NFC-CNT composite material, whereas the desire is to optimize, for example, mechanical properties of the composite material, the energy required to disperse used nanomaterials and the size ratios of those materials may differ considerably. As an exception from the usual dissertation work, the results achieved in the study have been concretized when functional heating elements have been produced based on two different processes. The first heating element "Salmiakki" has been featured in several seminars and fairs in addition to media prominence. The second heating element solution got closer to the public from the research world when it was integrated into the Liune sliding door and presented at the "Pyörre" exhibition house of Lohja Housing Fair 2021

The 2nd International Electronic Conference on Applied Sciences

This book is focused on the works presented at the 2nd International Electronic Conference on Applied Sciences, organized by Applied Sciences from 15 to 31 October 2021 on the MDPI Sciforum platform. Two decades have passed since the start of the 21st century. The development of sciences and technologies is growing ever faster today than in the previous century. The field of science is expanding, and the structure of science is becoming ever richer. Because of this expansion and fine structure growth, researchers may lose themselves in the deep forest of the ever-increasing frontiers and sub-fields being created. This international conference on the Applied Sciences was started to help scientists conduct their own research into the growth of these frontiers by breaking down barriers and connecting the many sub-fields to cut through this vast forest. These functions will allow researchers to see these frontiers and their surrounding (or quite distant) fields and sub-fields, and give them the opportunity to incubate and develop their knowledge even further with the aid of this multi-dimensional network

Tuning Surface Morphology of Fluorescent Hydrogels Using a Vortex Fluidic Device.

In recent decades, microfluidic techniques have been extensively used to advance hydrogel design and control the architectural features on the micro- and nanoscale. The major challenges with the microfluidic approach are clogging and limited architectural features: notably, the creation of the sphere, core-shell, and fibers. Implementation of batch production is almost impossible with the relatively lengthy time of production, which is another disadvantage. This minireview aims to introduce a new microfluidic platform, a vortex fluidic device (VFD), for one-step fabrication of hydrogels with different architectural features and properties. The application of a VFD in the fabrication of physically crosslinked hydrogels with different surface morphologies, the creation of fluorescent hydrogels with excellent photostability and fluorescence properties, and tuning of the structure-property relationship in hydrogels are discussed. We conceive, on the basis of this minireview, that future studies will provide new opportunities to develop hydrogel nanocomposites with superior properties for different biomedical and engineering applications