Dorian Liepmann (Advisor)

Research Advised by Professor Dorian Liepmann

BPN757: Biosensors Based on Biologically Responsive Polymers

Kiana Aran
2015

This project presents the design, fabrication and testing of novel plastic-based lab-on a chip (LOC) biosensors which utilize stimuli responsive polymers as their recognition element. The biosensors are composed of interdigitated electrodes (IDE) coated with a thin film of a responsive polymer. In the presence of stimuli, the responsive polymer degrades from the surface of the IDE, and generates a measurable electrical signal that correlates with the amount of stimuli present in the sample. This technology can be utilized as an accurate, label-free, cost-effective method for...

BPN756: MEMS Devices for Oral Delivery of Proteins and Peptides

Kiana Aran
Marc Chooljian
2016

Oral delivery of proteins and large molecule drugs has been a challenge due to the denaturing effects of digestive environment, enzymatic destruction and poor GI mucus permeability, leading to extremely low drug bioavailability and therapeutic efficacy. In spite of considerable efforts over the past decades, oral delivery of proteins and large molecule drugs with low therapeutic efficacy and bioavailability remains a major challenge. There is a great need for a suitable oral delivery system which can maintain the protein integrity, improve bioavailability and overcome the mucus...

BPN732: The Role of Erythrocyte Size and Shape in Microchannel Fluid Dynamics

Kathryn Fink
Karthik Prasad
2017

The unique properties of blood flow in microchannels has been studied for nearly a century; much of the observed blood-specific dynamics is attributed to the biconcave shape of red blood cells. However, for almost twice as long biologists have observed and characterized the differences in size and shape of red blood cells among vertebrates. With a few exceptions, mammals share the denucleated biconcave shape of erythrocytes but vary in size; oviparous vertebrates have nucleated ovoid red blood cells with size variations of a full order of magnitude. We utilize micro-PIV and pressure...

BPN847: A 3D Printed Microfluidic-Based Blood Filtration Device Examines the Effect of Blood Components in the Aging Process

Kiana Aran
Daniel Park
2017

Studies on blood parabiosis between young and old mice have shown reversals in the progression of aging. However, the definitive cellular elements in young mice that advance rejuvenation in old mice are yet to be identified. The goal of this project is to determine the specific blood component in young mice responsible for rejuvenation in old mice. This project focuses on designing a microfluidic-based blood exchange device capable of continuously separating and exchanging different type of blood components during blood transfusion between small animals to help identify the blood...

BPN711: Point-of-Care System for Quantitative Measurements of Blood Analytes Using Graphene-Based Sensors

Marc Chooljian
2017

Serum glucose, cholesterol, triglyceride and HbA1C monitoring are all valuable tools in the health management of the aging population, especially given the increase in diabetes and cardiovascular diseases. Even for glucose monitoring, the challenges obtaining sufficiently accurate and reliable measurements are so significant that the FDA is contemplating more stringent standards. Guido Freckmann, et al., J. Diabetes Sci. Tech. 6, 1060-1075, 2012, have compared 43 blood glucose self- monitoring systems. Out of this, 34 systems were completely assessed and 27 (79.4%) systems fulfilled...

BPN863: In Situ Gold Plating of Microfluidic Devices

Marc Chooljian
2017

Microfluidic devices are currently limited in their application potential by the lack of appropriate sensors or integrated electrodes. Building on the work of Prof. Dorian Liepmann's lab in electrodeposited electrodes and hot embossing, where deposited electrodes in contact with fluid channels are composed primarily of nickel, we endeavor to develop a novel process for gold-electroplating those nickel surfaces, within the channel, after the chip has been constructed (in situ). By using this process the metallic surfaces in contact with the electrolyte in the channel can be chemically...

BPN729: Development of Microfluidic Devices with Embedded Microelectrodes Using Electrodeposition and Hot Embossing

Marc Chooljian
2019

The use of microfluidic devices has experienced a tremendous increase over the last years, which is especially valuable for healthcare applications. In this context, plastic materials are increasingly relevant, especially for large scale fabrication and commercialization. However, plastics are still not widely used at the research level due to the lack of available inexpensive industrial-like fabrication equipment. In this work, we describe a rapid and highly cost-effective approach for fabricating plastic microfluidic...

BPN839: Flow Control in Plastic Microfluidic Devices Using Thermosensitive Gels

Marc Chooljian
2019

Our new microfabrication process can integrate electronics into plastic devices, simplifying on chip sensing and actuation. Traditional microfluidic prototyping (PDMS soft-lithography) requires large off chip components for active flow control. These components impose scalability limitations. Leveraging thermo-gelling polymers and integrated resistive heaters we can implement on chip active flow control. These polymers, poloxamers, are nonionic triblock copolymers known for their temperature dependent self-...

BPN907: Pressure-Based Interrogation of Platelet Activation

Aaron J. Velasquez-Mao
Natalie Simonian
2019

Platelets are stimulated by mechanochemical cues to trigger hemostatic and regenerative responses. Platelet activation, especially in the case of clotting, is generally thought of to be caused by shear- based forces. However, clinical observation suggests that pressure plays an influential role in the mechanical microenvironment. To probe the ways and extent to which pressure influences platelet activation and secretion of factors, we will develop a series of microfluidic devices to apply various magnitudes, gradients, and frequencies...

BPN870: Hot Embossed Thermoplastic Bubble-Actuated Micropump

Marc Chooljian
Ani Siyahian
2019

Advances in technology have allowed for the development of health diagnostics microdevices, but implementation of microdevices for drug delivery is relatively new. Continuous drug delivery often requires large and complex pumps, making development of micropumps desirable. Similarly, commonly used materials such as silicon are too expensive for mass production of disposable devices, and polydimethylsiloxane (PDMS) is not compatible with some pharmaceutical drugs due to partitioning effects in the PDMS matrix. Thermoplastic...