A General Purpose Programmable Microfluidic Platform for Screening and Optimization of Biological Assays

Screening is a fundamental process in today’s medicine and clinical diagnostics, comprising of several processes ranging from finding new target molecules having the desired therapeutic potential to identifying biomarkers for accurate diagnosis of a spectrum of diseases. Current high throughput screening (HTS) platforms leverage sophisticated robotics to perform a large number of experiments very quickly, an otherwise unmanageable task with manual labor. However, these systems are capital intensive which limit their use to large pharmaceutical companies or larger research labs. Additionally, reagent consumption is of the order of 10-100 µL per assay, which leads to substantial consumables cost. Recently proposed droplet microfluidic technologies have the potential to substantially reduce assay costs by performing reactions using nanoliter volumes at very rapid rates. However, their incorporation into screening workflows is limited owing to various technological challenges such as on-chip droplet storage for long incubation assays, fluid waste due to large dead volumes, lack of programmable control over individual assay droplets, etc

Reactions in droplets in microfluidic channels

Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights

Methodology for Trace and Ultratrace Analysis of Primary Amines

In the study of lipids, or lipidomics, methods for the separation and identification of specific trace compounds are highly sought. Microdroplet techniques have allowed for the ability to handle and detect these trace amounts. The use of low volumes allows for a decrease of the effective mean free path allowing chemical reactions to be carried out efficiently at lower concentrations by performing the reactions in microdroplets as opposed to bulk containers. Microdroplets created on microfluidic devices as segmented flow plugs have the advantage of efficient mixing and minimal dilution or dispersion relative to other nanoliter scale capillary reaction methods. The most sensitive detection techniques are needed for ultratrace analyses. Laser induced fluorescence (LIF) is the most attractive choice for ultratrace analysis. We show two methods for the derivatization and detection of primary amines with 3-(2-furoyl)quinoline-2-carboxaldehyde (FQCA) and with naphthalene-2,3-dicarboxaldehyde (NDA). The method has shown to be successful down to the sub-picomolar level in bulk solutions using an HPLC coupled with a fluorescence detector. The method has been transferred to microfluidic chips to explore the reaction and detection limits of the derivatized amines. Laser induced fluorescence (LIF) by a solid state blue violet laser was used as the detection method for the microfluidic platform. Successful usage of this methodology would allow for ultratrace detection of bioactive amines from small samples

Pharmachk: robust device for counterfeit and substandard medicines screening on developing regions

Thesis (Ph.D.)--Boston UniversityCounterfeit and substandard medicines are a grave public health concern that comprises a $75B black market and claims over 100,000 lives every year. The World Health Organization estimates that 10-50% of medicines in countries around the world are adulterated, and their presence imposes serious financial and economic burdens while also contributing to the rise of drug-resistant pathogens. Although a plethora of technologies are available for field-based quality screening, none reliably quantify active pharmaceutical ingredient (API) content or kinetic release from a dissolving tablet. The United States Pharmacopeia, a global leader in medicines standards for over 150 years, indicates that these quality measures are vitally important yet remain outside of the reach ofexisting screening tools. The current field standard relies on thin layer chromatography to only provide qualitative results that make it difficult to discern between tablets that contain 80% and 100% API. Meanwhile, international standards set the threshold for substandard medicines at 90%. This clear lack of appropriately quantitative and field- ready analytical tools poses a serious problem for national and international policymakers who are plagued with wildly variable information that prevents focused and deliberate action against the spread ofthese medications. This work presents an alternative analytical technique that can specifically and accurately quantify drug API content and kinetic release. PharmaChk provides an orthogonal approach to existing technologies using a portable, inexpensive, and easy-to-use platform. We demonstrate that aptamers can provide a simple and effective way to target a wide range of APis, while maintaining high quantitative precision and accuracy. A microfluidic, flow-through system is employed to obtain valuable drug quality information using a single step procedure. Through our research, we demonstrate the development of the PharmaChk platform from the proof-of-concept stage to beta prototyping and field-testing. By providing a portable, robust, and quantitative approach to medicines testing, PharmaChk can enable the collection of important drug quality information throughout pharmaceutical supply chains and ultimately save the lives of millions that are not afforded safe and essential medicines