Načrtovanje in testiranje mikrofluidne naprave za ločevanje delcev različnih velikosti

Karlič, Uroš (author), Plazl, Igor (mentor)

Mikrofluidika je veda, ki preučuje tok tekočin v mikroskopskem merilu. Mikrofluidne naprave sestavljajo mikrokanali različnih oblik in so vsestransko uporabne, in sicer od številnih aplikacij v medicini za hitrejše in enostavnejše diagnosticiranje bolezni, ločevanje celic do testiranja in dostave zdravil. Pri izdelavi mikrofluidne naprave je potrebno upoštevati več dejavnikov, od teh je najpomembnejši namen uporabe naprave. V magistrskem delu sem načrtoval, izdelal in testiral mikrofluidno napravo spiralne oblike, s katero bi lahko uspešno ločevali delce različnih velikosti. Takšno mikrofluidno napravo bi lahko z dodatnimi testiranji uporabili za ločevanje celic v medicinske namene. Z mehko litografijo smo izdelali dva prototipa mikrofluidne naprave iz polidimetilsiloksana (PDMS), ki sta se razlikovala po dimenziji izhodov. Napravi smo nato testirali pri različnih pretokih (do največ 520 µL/min) s suspenzijami mešanic polimernih kroglic velikosti 4,5 μm in 10 μm. Z digitalnim optičnim mikroskopom smo opazovali dogajanje in tvorbo tokov vzdolž kanala. S pomočjo obeh mikrofluidnih naprav nam je uspelo koncentrirati vzorec in vzpostaviti pogoje v mikrokanalu, pri katerih so se začeli uspešno tvoriti t.i. »vlakci« oziroma fokusni tokovi, vendar nam zaradi izbrane tehnike izdelave in materiala ni uspelo ustvariti pogojev za uspešno ločevanje delcev. Na podlagi dobljenih rezultatov eksperimentalnega dela je razvidno, da izdelani prototip ni primeren za ločevanje delcev pod tako visokimi pretoki, kljub temu pa je dobra osnova za nadaljnje raziskave na tem področju.

• Language: Slovenian
• Keywords: mikrofluidna naprava, separacija delcev, koncentriranje vzorca, mehka litografija, PDMS.
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2023
• PID: 20.500.12556/RUL-149733
• COBISS.SI-ID: 169823747
• Publication date in RUL: 08.09.2023

Secondary language

• Language: English
• Title: Design and testing of a microfluidic device for the separation of particles of different sizes

Abstract

Microfluidics is the study of the flow of fluids on a microscopic scale. Microfluidic devices consist of microchannels of different shapes and have a wide range of applications, from numerous medical applications for faster and easier diagnosis of diseases, cell separation to drug testing and delivery. Several factors need to be taken into account when designing a microfluidic device, the most important of which is the intended use of the device. In my master's thesis, I designed, fabricated, and tested a spiral-shaped microfluidic device that could successfully separate particles of different sizes. With additional testing, such a microfluidic device could be used for more effective cell separation in medical applications. Using soft lithography, we created two prototypes of the microfluidic device from polydimethylsiloxane (PDMS), which differed in the dimensions of their outlets. Subsequently, we tested these devices at various flow rates (up to a maximum of 520 µL/min) using suspensions of mixtures of polymeric beads sized 4.5 μm and 10 μm. The dynamics and formation of flows along the channel were observed using a digital optical microscope. With the help of both microfluidic devices, we successfully concentrated the sample and established conditions in the microchannel where so-called "trains" or focal flows began to form. However, due to the fabrication technique and material used, we were unable to create conditions for successful particle separation. Based on the obtained results from the experimental work, it is evident that the developed prototype is not suitable for particle separation under such high flow rates. However, it serves as a good foundation for further research in this field.

• Keywords: microfluidic device, particle separation, sample concentration, soft lithography, PDMS.