Search

Transkriptom so vse molekule RNA v celici ali tkivu. Transkriptomika je veda, ki preučuje transkriptom in pomaga pri razumevanju regulacije izražanja genov in bioloških procesov. Sekvenciranje transkriptoma iz tkiv pokaže izražanje genov velikega števila celic. Transkriptomika na nivoju posamezne celice pa omogoča vpogled v gensko izražanje ene celice. Ponuja boljši prikaz razlik med posameznimi celicami in njihovimi funkcijami. Da se lahko spustimo na raven ene celice moramo celice najprej ločiti med sabo. Preučujemo lahko specifične redke celične tipe ali pa obdelamo veliko število celic naenkrat. Celice lahko ločujemo tudi po velikosti in s pomočjo fluorescence, glede na njihove molekularne markerje. Prepise pridobljenih posameznih celic unikatno označimo in pripravimo knjižnico za sekvenciranje. Sekvenciramo z visokozmogljivimi tehnologijami, ki delujejo na principu sekvenciranja s sintezo. Pridobljene podatke nato računalniško obdelamo. Obstaja tudi metoda sekvenciranja transkriptoma posameznih jeder, ki omogoča raziskovanje celic, ki jih je težko izolirati iz tkiva in zamrznjenih vzorcev. Metoda preučevanja transkriptoma na nivoju ene celice se uveljavlja na številnih področjih. V raziskavah zgodnjega embrionalnega razvoja omogoča vpogled v uravnavanje izražanja genov že v fazi morule. V nevroznanosti omogoča spremljanje diferenciacije celic. Pri razvoju tumorjev je omogočila iskanje novih tarč za zdravila pri redkih populacijah celic. Uveljavlja se v raziskavah rastlin. The transcriptome is the set of RNA molecules in a cell or tissue. Transcriptomics is the study of the transcriptome to understand the regulation of gene expression and biological processes. Sequencing the transcriptome of tissues shows gene expression in many cells. Transcriptomics at the single cell level provides insight into the gene expression of a single cell. This gives a better indication of the differences between individual cells and their different functions. To get down to the level of a single cell, we need to first separate the cells. You can search for specific rare cell types or process many cells at once. Cells can also be distinguished by their size and fluorescence, depending on their molecular markers. Once we have the individual cells, we uniquely label their transcripts and prepare the library for sequencing. We sequence using high-throughput technologies that work on the principle of sequencing by synthesis. The data are then processed by computer. A method for sequencing the transcriptome of individual cell nuclei has also been developed, allowing the study of cells that are difficult to extract from tissue and frozen samples. Transcriptomics at the single cell level is gaining traction in many fields. In studies of early embryonic development, it provides insights into the regulation of gene expression, even at the morula stage. In neuroscience, it enables monitoring of cell differentiation. In tumor development, it enabled the search for new drug targets in rare cell populations. It is used in plant research.

Sodobne izdelovalne tehnologije omogočajo izdelavo mikrofluidičnih čipov, ki omogočajo enostavno in učinkovito izvedbo analiz in diagnostike na različnih področjih. Pri tem je pogosto potrebna izvedba procesa mešanja na mikroskali, ki pa je težavno zaradi izrazito laminarnih tokov. V zaključni nalogi so predstavljene osnovne fizikalne značilnosti tokov v mikrokanalih, različni načini izdelave in tipi pasivnih mikrofluidičnih mešal ter popis metod za ovrednotenje kakovosti mešanja v mikrofluidiki. Zasnovali, izdelali in preizkusili smo štiri pasivna mikromešala ter nato ovrednotili njihovo učinkovitost z opazovanjem spreminjanja kontrasta dveh barvil prek optičnega mikroskopa. Ovrednotenje je pokazalo, da najboljše mešanje doseže mešalo s cikcak obliko. Modern fabrication technologies enable the production of microfluidic chips that allow easy and efficient analysis and diagnostics in a wide range of fields. This often requires a mixing process at the microscale, which is difficult due to the highly laminar flows. This thesis presents the basic physical characteristics of microchannel flows, different fabrication methods and types of passive microfluidic mixers, and an inventory of methods for evaluating the quality of mixing in microfluidics. Four passive micromixers were designed, fabricated and tested, and then their performance was evaluated by observing the change in contrast of two dyes through an optical microscope. The evaluation showed that the best mixing is achieved by the mixer with a zigzag shape.

Namen diplomske naloge je bil optimizacija aparature za pripravo homogene aktivne nematske emulzije olja v vodi z možnostjo manipuliranja velikosti kapljic v mikro dimenzijah in nato preučiti interakcijo med sosednjimi aktivnimi nematskimi lupinami, ko se majhno število oljnih kapljic razprši v aktivnem gelu in postavi v utesnjen prostor. Za generiranje oljnih kapljic smo uporabili mikrofluidno aparaturo z geometrijo sočasnega toka, ki je bila sestavljena iz steklenih kapilar s krožnim in kvadratnim prerezom, skozi katere so nanofluidne črpalke potiskale različne tekočine. Pričakovali smo, da v zaprtosti običajno neodvisni kortikalni tokovi na ločenih kapljicah doživijo hidrodinamično sklopitev, ki bi lahko vodila do zanimivih sinhronizacijskih pojavov, ki so pomembni za razumevanje organizacije večceličnih struktur. The aim of my thesis was optimization of the apparatus for the preparation of a homogeneous active nematic oil-in-water emulsion with the possibility of manipulating the droplet size in micro dimensions and then to study the interaction between neighbouring active nematic shells when a small number of oil droplets is dispersed in the active gel and placed in a confined volume. We used a droplet-generating coflowing device, based on the combination of tapered glass capillaries with circular and square cross section through which different fluids were pushed using nanofluidic pumps. We expected that, under confinement, the normally independent cortical flows in separate droplets experience a hydrodynamical coupling that may lead to interesting synchronization phenomena, which may be relevant to the understanding of the organization of multicellular structures.

V diplomskem delu je predstavljena obravnava fokusiranja delcev v ravnem mikrofluidnem kanalu. Izvedena je teoretična študija na osnovi mrežne Boltzmannove metode, sklopljene z robnimi pogoji s potopljenimi mejami. V začetku je izvedena validacija numerične metode na primeru fokusiranja enega samega delca in urejanja delcev v homogeni suspenziji. V nadaljevanju so obravnavane heterogene suspenzije z delci dveh različnih velikosti, ki do sedaj teoretično še niso bile obravnavane. Preverjen je vpliv Reynoldsovega števila in razmerja polmerov delcev na tvorbo urejenih struktur. Dodatno je predstavljen vpliv Reynoldsovega števila in velikosti delcev na čas fokusiranja. Demonstrirano je, da obstaja določeno kritično razmerje polmerov delcev, ki prepreči tvorbo stabilnih struktur. Dodatno je ugotovljeno, da na obliko urejenih struktur Reynoldsovo število nima bistvenega vpliva, ima pa vpliv na čas fokusiranja. In the following thesis we are concerned with particle focusing based on the inertial lift effect in straight microfluidic channels. Extensive numerical simulations based on the lattice Boltzmann method coupled to immersed boundary conditions were performed. We start by first validating the numerical method on simple cases of a single particle focusing and with particle ordering in a homogenous suspension. We continue by applying the validated numerical framework to heterogenous bidisperse suspensions. The influence of the Reynolds number and particle diameter ratio on particle train formation is investigated. The effect of particle size and Reynolds number on focusing time is also discussed. We demonstrate that there exists a critical ratio of radii where a stable particle train cannot be formed. Reynolds number was not found to have a significant effect on the final particle configuration, but did influence the focusing times.

Na področju mikrofluidike je v zadnjem desetletju opaziti večje zanimanje za implementacijo mikrovalov v mikrofluidne sisteme. Oboji izkazujejo intenzifikacijo mnogih procesov zaradi lastnosti opisanih v tretjem in četrtem poglavju. V petem poglavju sledi pregled dognanj na področju vnosa toplotne energije v mikrofluidne sisteme z različno konstruiranimi aplikatorji mikrovalov in primerov uporabe mikrovalov za vodenje reakcij v mikroreaktorjih. V šestem poglavju so opisana dognanja na področju analize bioloških vzorcev z mikrovalovi v mikrofluidiki. Poglavitna prednost mikrovalov je brezkontaktno gretje in hkrati merjenje različnih karakteristik obsevane snovi. Mikrofluidni sistemi izkazujejo skoraj takojšnji odziv na spremembo v mikrovalovih, zato je posebej obetavno področje uporabe verižna reakcija s polimerazo, kjer je natančen nadzor temperature izjemnega pomena. In the field of microfluidics, there has been a growing interest in the implementation of microwaves in microfluidic systems over the last decade. Intensification of many processes is shown by usage of both, due to the properties described in third and fourth chapters. In the fifth chapter, findings in the field of heat input into microfluidic systems with differently designed microwave applicators and examples of the use of microwaves to control reactions in microreactors, are being reviewed. The sixth chapter describes the findings in the field of analysis of biological samples with microwaves in microfluidics. The main advantage of microwaves is non-contact heating and measuring various characteristics of the irradiated substance simultaneously. Microfluidic systems show an almost immediate response to a change in microwave irradiation intensity, therefore a particular promising area of application is the polymerase chain reaction, where precise temperature control is of immense importance.

S povečevanjem populacije in posledičnim pomankanjem kmetijskih površin in zalog vode postajajo oceani vse pomembnejši vir potrebnih hranilin obnovljivih surovin. Posledično vse večji pomen pridobiva tudi biomasa iz alg. Vzhodne kulture so alge že tradicionalno uporabljale v prehrani. V sodobnosti se je uporaba razširila tudi na področje farmacije, saj so alge bogate z različnimi bioaktivnimi komponentami, ki imajo pozitivne vplive na zdravje ljudi. V svojem diplomskem delu sem želela razviti postopek za integrirano čiščenje izbranega proteina iz ekstrakta alg rodu Gracilaria. Ta rod rdečih alg je zanimiv predvsem zaradi vsebnosti proteina R-fikoeritrina, ki ima vlogo pomožnega fotosintetskega barvila. Ker je omenjen protein slabo stabilen, je potrebno v procesu čiščenja uporabiti blage pogoje. Dvofazni vodni sistemi z miceli, ki temeljijo na vodnih pufrih in surfaktantih, zato predstavljajo velik potencial na področju izolacije občutljivih biomolekul. Preizkusili so jih že v šaržnih procesih ter v miniaturiziranih pretočnih napravah, kjer so na osnovi hitre temperaturne spremembe dosegli tvorbo dvofaznega sistema ter nadaljnjo separacijo faz. Namen diplomske naloge je bila nadgradnja čiščenja R-fikoeritrina v predhodno razvitem sistemu mikrofluidnih naprav, kjer sem v sistem vključila ultrafiltracijski modul. Poleg tega sem dodala tudi mešalne elemente, ki so omogočali mešanje vhodne raztopine, s čimer sem dosegla homogeno sestavo vhodne raztopine ekstrakta alg. Proces sem primerjala tudi s šaržnim procesom čiščenja R-fikoeritrina. Dobljeni rezultati nakazujejo, da je čiščenje z integriranim mikrofluidnim sistemom učinkovitejše kot šaržni proces. Za izboljšanje procesa pa bi bilo potrebno uporabiti bolj učinkovite mešalne elemente, saj z uporabljenimi pasivnimi mikro-mešalniki nisem uspela zadovoljivo pomešati vhodne raztopine. With the growth of the global population and consequential lack of agricultural land as well as freshwater supplies, the oceans are becoming an increasingly important source of vital nutrients and renewable resources. Within this context, algae biomass is gaining even greater significance. Particularly in Eastern cultures, algae have traditionally been used in the human diet their uses have recently extended to the area of pharmacy, especially due to their various bioactive compounds and their positive effects on human health. In my thesis, I wanted to develop a procedure for integrated purification of the protein using extract prepared from the algae of the Gracilaria genus. This genus is prized for its phycoerythrin content, which acts as an ancillary photosynthetic pigment. Because of the protein's low stability, it is of vital importance to keep mild conditions in the process of purification. Therefore, aqueous micellar two-phase systems, based on buffer solutions and surfactants, represent great potential in case of sensitive biomolecules isolation. They have already been tested in batch processes and also within microfluidic devices, where an aqueous micellar two-phase system and further phase separation were achieved as a result of quick temperature change. The purpose of my thesis was an upgrade of the purification of R-phycoerythrin in a previously developed system of microfluidic devices, with the addition of an ultrafiltration module. Furthermore, I also added an array of mixing elements that permitted mixing of the aqueous solution, which gave me a homogenous inlet solution of algal extract. The process was also compared with the batch process of R-phycoerythrin purification. The results show that the purification with an integrated microfluidic system is more efficient than the batch process. Moreover, using better mixing elements would be necessary to improve the process, as the inlet solution could not be properly mixed with passive micromixers.

V doktorski disertaciji sem raziskal optične in temperaturne vplive zunanjih polj na direktorsko polje nematskega tekočega kristala v različnih tokovnih režimih znotraj mikrofluidičnih kanalčkov z močnim homeotropnim sidranjem. Uporabljal sem polarizacijski optični mikroskop, opremljen z lasersko pinceto, ki pri večjih močeh laserske svetlobe zaradi absorpcije v prevodnem substratu mikrokanalčka povzroči lokalno segrevanje nematika v izotropno fazo in ob hipnem ugašanju posledično sproži hiter fazni prehod v nematsko fazo. Na ta način sem pokazal, da je z laserskim snopom optične pincete v toku nematika mogoče nukleirati in stabilizirati topološko ograjene, orientacijske domenske strukture. Raziskal sem dinamiko teh struktur pri različnih hitrostih toka in skonstruiral fazni diagram prehodov med podkritičnim in nadkritičnim območjem parametrov, ki kvantitativno ločijo krčenje in širjenje domen v dani geometriji. Osredotočil sem se na frekvenčne modulacije tokovnih režimov in relaksacijske procese ob zaustavitvi tokov, ki povzročijo reorientacijo v domeno ujetega direktorskega polja in nastanek točkastih defektov s solitoni. Pokazal sem, da je orientacijske domenske strukture, razen v nematiku 5CB, mogoče tvoriti in stabilizirati tudi v tekočem kristalu CCN z negativno dielektrično anizotropijo in majhno optično dvolomnostjo. Izkazalo se je, da temperaturne spremembe v mikrofluidičnem kanalčku znatno vplivajo na stabilnost z laserjem segretih nematskih plasti, tvorjenje domenskih struktur in na tokovne režime, zato sem te pojave podrobneje raziskal pri višji temperaturi. Pri faznem prehodu toka tekočega kristala iz izotropne v nematsko fazo sem zasledil soobstoj nematskih in izotropnih domen. Nato sem z različnimi geometrijami mikrokanalčkov kontrolirano vplival na obliko, velikost in življenjski čas domen, saj ima takšna manipulacija anizotropne tekočine potencial za uporabo v kompleksnejših mikrofluidičnih vezjih, senzorjih tlaka in nastavljivih optičnih filtrih. S tokom potujoče domene lahko tudi razcepimo, združujemo in sortiramo. V sodelovanju s teoretičnimi fiziki sem kot prvi pokazal obstoj novega kiralnega stanja v toku homeotropnega nematika, ki je doslej, zaradi premalo natančne regulacije tokov, ostalo neopaženo. Nazadnje sem preučil vpliv električnega polja na tokovne režime in domenske strukture. Zaradi dielektrične anizotropije in polarizabilnosti tekočekristalnih molekul lahko z električnim poljem spreminjamo obliko domenskih struktur, jih pri tem razpolavljamo, usmerjamo ali pa jih z močnejšim preklapljanjem električnega polja celo tvorimo. Precizna frekvenčna modulacija električnega polja je nenazadnje uporabna za tvorbo kiralnih domenskih stanj brez uporabe laserske pincete. In the thesis I examine optical and thermal effects on the nematic director field configurations in various flow regimes confined to microfluidic channels with homeotropic surface alignment. Polarizing optical microscopy in combination with laser tweezers is applied to locally heat the nematic flow into the isotropic phase and quench it back to the nematic phase. Thereby, realigned phase domains with encircled defect loops are nucleated, stabilized and transported in a flowing nematic phase. I study the dynamic evolution of orientational phase domains in stationary nematic microflows to construct a phase diagram of shrinking and growing loops for a wide range of flow velocities. Further, I focus on careful tuning and active control of the flow to reveal reorientational dynamics of the flow-aligned director field in oscillatory flows, followed by a nucleation of solitons and point defects as it seeks relaxation to equilibrium. I demonstrate the phenomena in single component liquid crystal 5CB, as well as in a mixture of two CCN liquid crystals with negative dielectric anisotropy and very low birefringence. The laser light interaction with the confined nematic flow is further explored at higher temperatures that approach the nematic to the isotropic phase transition. The study shows impacts of heating on the stability of applied optical traps, nucleation and coexistence of oriented nematic and isotropic domains, and evolution of flow regimes after cooling back to the nematic phase. Next, I demonstrate the dynamic control over the growth and shape of nematic domains by varying only the shape of the channels. This way, splitting and coalescence of the domains can be achieved without use of the laser tweezers. The complete control over domain size manipulation and their birefringent colors may find applications in highly sensitive microfluidic pressure sensors or tunable optofluidic filters. In collaboration with theoretical physicists, I present a hidden pre-transitional state with broken chiral symmetry which can occur before the homeotropic to flow-aligned transition, and characterize the underlying mechanisms of its formation. Lastly, I study effect of external electric field on different flow regimes and domain structure formation. Due to the dielectric anisotropy and the polarizability of liquid-crystalline molecules, applied electric field can reorient, split or nucleate the before-studied flow-aligned domains. Finally, precise frequency modulation of an alternating electric field can produce a sequence of chiral domains in a steady nematic flow.

V pričujočem diplomskem delu sta predstavljena izdelava in testiranje sistema digitalne mikrofluidike. Mikrofluidika je področje, ki zajema transportne pojave majhnih volumnov tekočin z uporabo majhnih kanalov. Obravnavamo manipulacijo kapljice s pomočjo spreminjanja njene površinske napetosti, kar imenujemo električno omočenje površine na dielektriku, ki temelji na spreminjanju električnega potenciala. Opisani pojav se uporablja v farmacevtski industriji, predvsem zaradi možnosti manipuliranja majhnih volumnov različnih tekočin ter avtomatizacije procesov mešanja in doziranja tekičin na mikroravni. Hkrati se lahko izkorišča za transport toplote pri ohlajanju večjega števila lokalnih toplotnih virov na neki površini, denimo računalniškem procesorju. V delu so opisane osnove delovanja principa omočenja površine na dielektriku, postopek izdelave in podani rezultati testiranja sistema digitalne mikrofluidike. In final thesis design and testing of a digital microfluidics system is presented. Microfluidics is an area that covers transport of small volumes of liquids using small channels. In this thesis we cover manipulation of a droplet by changing its surface tension. This technique is called electrowetting on dielectric that is based on changing the electrical potencial. The applicability of this phenomenon is noticeable in pharmaceautical industry, mainly due to its capability to manipulate small volumes of various liquids and ability to automate mixing and dosing processes at the micro-level. The phenomenon can be also used for heat transfer such as cooling large number of local heat sources on the surface such as computer processor. This thesis covers basic concepts of electrowetting on dielectric. The following describes process of designing and testing results of a digital microfluidics system.

V zadnjih letih je pojav mikrofludnih naprav, kjer imamo dve različni nemešljivi tekočini, vzbudil zanimanje strokovnjakov na mnogih področjih, saj je njihovo delovanje napram napravam, ki uporabljajo samo eno fazo boljše. Za lažje konstruiranje naprav in razumevanje procesov v njej je potrebno dobro teoretično znanje fluidne dinamike, pomagajo nam tudi numerične metode s katerimi simuliramo delovanje naprav. Posebej pomembna je sama oblika toka, ki nastane v napravi. Če nastajajo kapljice, lahko vsaka kapljica predstavlja reaktor v katerem poteka kemijska reakcija, zato je zelo pomembno dobro razumevanje nastanka kapljic. Obstaja veliko različnih konfiguracij mikrofludnih naprav in vsaka od njih ima svoje prednosti in slabosti. Za uspešno reševanje problemov z mikrofluidnimi napravami je pomembno znanje o možnih konfiguracijah, zakonitosti posameznih konfiguracij s katerimi si bomo pomagali pri dizajniranju naprave, tako da nam bo praktično služila. Ko so kapljice ustvarjene nas zanima kako potujejo po mikrofluidni napravi, ali jih lahko manipuliramo ali združujemo. To delo predstavlja pregled prej omenjenih procesov, lastnosti in pojavov v mikrofluidni napravi, kjer uporabljamo dve različni nemešljivi fazi. Development of microfluidic devices that use flow of two immiscible fluids has sparked interest in experts from many fields of nature science. interest lies in their capability to perform better than devices that use only one fluid. For easier and better construction of microfluidic devices is important to have good theoretical background in fluid dynamics and knowledge of numerical methods which are used to simulate working of those devices is also handy. Shape of flow is of particular importance. If microfluidic device produces droplets, each droplet can be interpreted as a small reactor in which chemical reaction is performed, that is why is important to understand process of droplet production. There are many different configurations of microfluidic devices, each one has it's own upsides and downsides. knowledge of such configuration is vital for designing microfluidic device that will be of practical use and will help us with our problems. Once droplets are formed, we are interested how can we manipulate them or marge. Presented work represents review of all processes, properties and phenomena in microfluidic device where two immiscible fluids are used.

Cianobakterije zaradi sposobnosti vezave ogljika in dušika ter sinteze organskih spojin iz ogljika vezanega s fotosintezo predstavljajo pomemben vir kompleksnih spojin z visoko vrednostjo, vendar pa se zaradi dragih postopkov za ekstrakcijo produktov in počasnega iskanja primernih sevov le redko uporabljajo. Zaradi številnih prednosti mikrofluidika lahko prispeva k hitrejšemu razvoju ekonomsko upravičenih procesov in tehnologij s cianobakterijami. V delu je povzet pregled raziskav, ki potrjujejo velik pomen uporabe mikrofluidnih naprav za izvedbo visokozmogljivostnih presejalnih testov, za analizo rasti in metabolizma cianobakterij ter za koncentriranje teh celic. Cyanobacteria present a potential source of complex high-value chemicals, due to their carbon fixation, nitrogen fixation, and photosynthesis capability. However, cyanobacteria are rarely used due to expensive product extraction procedures and slow strain selection processes. Microfluidics allows for high throughput assays through the manipulation of small volumes of liquid. Due to the flexibility of such systems, they may be used in many different applications as screening assays, concentrating and growth analysis under different conditions.

V diplomskem delu so v tretjem poglavju predstavljene osnove kompleksnih fluidov in matematični modeli, ki so pomembni za opis kompleksnih fluidov. V četrtem poglavju sem s pomočjo literature raziskal in opisal področje mikrofluidike, mikrofluidnih naprav ter najpomembnejše transportne pojave v mikrofluidnih sistemih. Predstavljeni so bili tudi materiali za izdelavo mikrofluidnih čipov ter fabrikacija mikrofluidnih naprav. V poglavju pet, sem se posvetil pregledu literature o pasivnih in aktivnih mikromešalnih napravah in njihovi uporabi. V zadnjem poglavju diplomske naloge je bilo glavno področje raziskovanja večfazni tok fluidov. Pri tem sem se osredotočil na pregled literature s področja nastanka nestabilnosti v dvokomponentnem toku v mikrofluidnih napravah. Ugotovljeno je bilo, da eden izmed ključnih dejavnikov za nastanek nestabilnosti v večfaznem toku, predvsem razlika v viskoznosti in gostoti komponent in da je mogoče s spreminjanjem volumenske frakcije fluidov, ter uravnavanjem hitrosti pretokov, nestabilnosti bodisi ojačati ali pa omejiti. Temeljna metoda dela pri izdelavi diplomske naloge je bil pregled literature, tako člankov kot knjig o omenjenih temah. In the third chapter of my diploma thesis some basic principles of complex fluids and mathematical models for their modelling are presented. The fourth chapter concentrates on the field of microfluidics, microfluidic devices and transport phenomena in microfluidics. In the chapter I also present different materials and methods for fabrication of microfluidic devices. In the chapter five the main goal was to present passive and active micromixers and their use in microfluidics. The last chapter of my diploma thesis was driven by research on multiphase flow of fluids. I also focused my research on summarizing literature on the formation of instabilities in the multiphase flow, from which I concluded that difference in viscosity and density of two fluids is one of the main reasons for formation of instabilities in a fluid network. From literature review I concluded that instabilities can be either enhanced or weakened by adjusting volume fraction of inlet fluids and flow rate. The main method of my research was literature review from articles, as well as books.

V magistrskem delu je predstavljen nov koncept merjenja hitrosti v mikrofluidičnem vezju, ki temelji na opazovanju gibanja delcev v tekočini v stranski komori, ki se ne meša z vzorcem v glavnem kanalu mikrofluidičnega vezja. Prikazane so teoretične osnove in numerična simulacija predlaganega senzorja. Opisan je postopek izdelave zasnovanega mikrofluidičnega vezja in izvedba meritev. Eksperimentalno je potrjen pojav sekundarnega toka v stranski komori in natančneje analizirano gibanje delcev v toku. Ugotovljena je korelacija med tem gibanjem in hitrostjo toka v glavnem kanalu. This master's thesis presents a new concept for velocity measurements in microfluidics, based on the observation of movement of colloidal particles in the secondary flow in the side chamber, filled with a fluid that does not mix with the sample in the main channel of the microfluidic system. First, theoretical basics and numerical simulation of proposed design are explained. Next, manufacturing of a sensor and the performed measurements are described. They are followed by detailed analysis of particle movement where correlation between the main channel flow velocity and side chamber particle movement is shown.

V diplomskem delu je predstavljen digitalni mikrofluidni biočip, ki je namenjen izvajanju preizkusov različnih človeških in okoljskih tekočin. Predhodnik digitalnega mikrofluidnega biočipa je zvezno pretočni mikrofluidni biočip, ki temelji na mehanskih komponentah za premikanje tekočin. Osnova za razvoj mikrofluidnih biočipov sta mikrofluidika in laboratorij na čipu, ki omogočata majhno velikost biočipov in prenosljivost naprav. V diplomskem delu so predstavljene zaporedne stopnje sinteze, ki ponazarjajo delovanje digitalnega mikrofluidnega biočipa. Splošni predstavitvi sinteze sledi opis vsake stopnje in algoritma posebej. Na koncu diplomske naloge je predstavljen simulator, s katerim lahko izvajamo sintezo in prikazujemo njene rezultate. This bachelor’s thesis presents a digital microfluidic biochip that is intended for carrying out tests on various human and environmental fluids. The predecessor of the digital microfluidic biochip is the continuous-flow microfluidic biochip, which is based on mechanical components for fluid movement. The basis for developing microfluidic biochips is microfluidics and the lab-on-a-chip, which make possible small biochips and device portability. This thesis presents sequential steps of synthesis that illustrate the operation of a digital microfluidic biochip. The general presentation of the synthesis is followed by a separate description of each step and algorithm. The thesis concludes by presenting a simulator that can be used to carry out synthesis and present its results.