We summarize the experiences and outcomes for 'discipline-based education specialists' involved with a large-scale, 10-year initiative: the Carl Wieman Science Education Initiative at the University of British Columbia. A key aspect of the initiative was the hiring of these specialists into academic departments where they held graduate-level education in a matching discipline, often coupled with teaching experience. We draw upon various data sources to provide a rich, longitudinal picture of the experiences and career trajectories of these academic developers and explore the skills, behaviours, and supports they perceive as critical for changing and advancing instructional practices and departmental culture in higher education. We also discuss how embedding agents of change this way is a successful model for the transformation of institutional norms in undergraduate education.

To develop expertise, novice chemistry students require deliberate practice with immediate and thoughtful feedback. Whereas opportunities for practice are often abundant, opportunities for feedback tend to be much scarcer. To address this challenge, we collaborated with students to develop a flexible and scalable online platform called "Alchemy." Students interact with the software through a series of prompts and multiple-choice questions, receiving targeted feedback at each step. Each student can navigate a scenario differently, influenced by their prior knowledge and misconceptions. In design, scenarios are instructor-created graphs that model their expert-level thought process(es) and teaching experience. This graph format is a distinct and advantageous feature of Alchemy that supports linear, nonlinear, and cyclical progression through a concept or problem. Alchemy-based homework has been assigned in lecture and lab courses, at the sophomore and junior levels, with enrollments ranging from many tens to many hundreds of students. Approximately 80% of students rated Alchemy as very/extremely helpful to their learning, emphasizing the value of the step-by-step process and feedback. Alchemy is discussed in the contexts of other software platforms, its advantages and limitations, lessons learned in its initial deployments, and future directions for its development and usage.

A quick, simple, and engaging demonstration of the spectrophotometric complementary color wheel is presented. Colored indicator dye solutions are illuminated under ambient room light and with different colors of light-emitting diodes (LEDs) in a dark room. The solutions are observed to be colored, black and opaque, or transparent and colorless in accordance with the color wheel, their optical absorption spectra, and the illumination conditions.

A guided-inquiry project designed to teach students the basics of spectrophotometric instrumentation at the second year level is presented. Students design, build, program, and test their own single-wavelength, submersible photometer using low-cost light-emitting diodes (LEDs) and inexpensive household items. A series of structured prelaboratory assignments guide students through the processes of researching background information, designing a photometer device, and developing their own procedure to test the performance of the device. Students also learn basic skills of data acquisition by programming an easy-to-use LabVIEW interface for their device. Using a colorimetric indicator dye, students use their photometers and LabVIEW interfaces to determine the endpoint of an acid base titration and compare the linear response of their device against that of a commercially available spectrophotometer. Students who completed the experiment indicated that the experience improved their understanding of spectroscopy, as well as their critical thinking skills and research ability.

Maxwell, E. J., McDonnell, L., & Wieman, C. E. (2015). An improved design for in-class review. Journal of College Science Teaching, 44(5), 48-52. Retrieved from http://www.cwsei.ubc.ca/SEI_research/files/Chem/Maxwell-Mcdonnell-Wieman_In-ClassReview_JCST2015.pdf

This paper describes an inexpensive, handheld device that couples the most common forms of electrochemical analysis directly to "the cloud" using any mobile phone, for use in resource-limited settings. The device is designed to operate with a wide range of electrode formats, performs on-board mixing of samples by vibration, and transmits data over voice using audio-an approach that guarantees broad compatibility with any available mobile phone (from low-end phones to smartphones) or cellular network (second, third, and fourth generation). The electrochemical methods that we demonstrate enable quantitative, broadly applicable, and inexpensive sensing with flexibility based on a wide variety of important electroanalytical techniques (chronoamperometry, cyclic voltammetry, differential pulse voltammetry, square wave voltammetry, and potentiometry), each with different uses. Four applications demonstrate the analytical performance of the device: these involve the detection of (i) glucose in the blood for personal health, (ii) trace heavy metals (lead, cadmium, and zinc) in water for in-field environmental monitoring, (iii) sodium in urine for clinical analysis, and (iv) a malarial antigen (Plasmodium falciparum histidine-rich protein 2) for clinical research. The combination of these electrochemical capabilities in an affordable, handheld format that is compatible with any mobile phone or network worldwide guarantees that sophisticated diagnostic testing can be performed by users with a broad spectrum of needs, resources, and levels of technical expertise.

This paper describes the design and fabrication of ion-sensing electrochemical paper-based analytical devices (EPADs) in which a miniaturized paper reference electrode is integrated with a small ion-selective paper electrode (ISPE) for potentiometric measurements. Ion-sensing EPADs use printed wax barriers to define electrochemical sample and reference zones. Single-layer EPADs for sensing of chloride ions include wax-defined sample and reference zones that each incorporate a Ag/AgCl electrode. In EPADs developed for other electrolytes (potassium, sodium, and calcium ions), a PVC-based ion-selective membrane is added to separate the sample zone from a paper indicator electrode. After the addition of a small volume (less than 10 μL) of sample and reference solutions to different zones, ion-sensing EPADs exhibit a linear response, over 3 orders of magnitude, in ranges of electrolyte concentrations that are relevant to a variety of applications, with a slope close to the theoretical value (59.2/z mV). Ion-selective EPADs provide a portable, inexpensive, and disposable way of measuring concentrations of electrolyte ions in aqueous solutions.

This paper describes the fabrication of pressure-driven, open-channel microfluidic systems with lateral dimensions of 45-300 microns carved in omniphobic paper using a craft-cutting tool. Vapor phase silanization with a fluorinated alkyltrichlorosilane renders paper omniphobic, but preserves its high gas permeability and mechanical properties. When sealed with tape, the carved channels form conduits capable of guiding liquid transport in the low-Reynolds number regime (i.e. laminar flow). These devices are compatible with complex fluids such as droplets of water in oil. The combination of omniphobic paper and a craft cutter enables the development of new types of valves and switches, such as "fold valves" and "porous switches," which provide new methods to control fluid flow.

This paper describes a method to detect the presence of bacteria in aqueous samples, based on the capture of bacteria on a syringe filter, and the infection of targeted bacterial species with a bacteriophage (phage). The use of phage as a reagent provides two opportunities for signal amplification: (i) the replication of phage inside a live bacterial host and (ii) the delivery and expression of the complementing gene that turns on enzymatic activity and produces a colored or fluorescent product. Here we demonstrate a phage-based amplification scheme with an M13KE phage that delivers a small peptide motif to an F+, α-complementing strain of Escherichia coli K12, which expresses the ω-domain of β-galactosidase (β-gal). The result of this complementation—an active form of β-gal—was detected colorimetrically, and the high level of expression of the ω-domain of β-gal in the model K12 strains allowed us to detect, on average, five colony-forming units (CFUs) of this strain in 1 L of water with an overnight culture-based assay. We also detected 50 CFUs of the model K12 strain in 1 L of water (or 10 mL of orange juice, or 10 mL of skim milk) in less than 4 h with a solution-based assay with visual readout. The solution-based assay does not require specialized equipment or access to a laboratory, and is more rapid than existing tests that are suitable for use at the point of access. This method could potentially be extended to detect many different bacteria with bacteriophages that deliver genes encoding a full-length enzyme that is not natively expressed in the target bacteria.

This paper describes the development of a referenced Electrochemical Paper-based Analytical Device (rEPAD) comprising a sample zone, a reference zone, and a connecting microfluidic channel that includes a central contact zone. We demonstrated that the rEPADs provide a simple system for direct and accurate voltammetric measurements that are referenced by an electrode with a constant, well-defined potential. The performance of the rEPADs is comparable to commercial electrochemical cells, and the layout can be easily integrated into systems that permit multiplexed analysis and pipette-free sampling. The cost of this portable device is sufficiently low that it could be for single-use, disposable applications, and its method of fabrication is compatible with that used for other paper-based systems.

Microfluidic paper-based analytical devices (μPADs) use the passive capillary-driven flow of aqueous solutions through patterned paper channels to transport a sample fluid into distinct detection zones that contain the reagents for a chemical assay. These devices are simple, affordable, portable, and disposable; they are, thus, well suited for diagnostic applications in resource-limited environments. Adding screen-printed electrodes to the detection zones of a μPAD yields a device capable of performing electrochemical assays (an EμPAD). Electrochemical detection has the advantage over colorimetric detection that it is not affected by interference from the color of the sample and can be quantified with simple electronics. The accessibility of EμPADs, however, is limited by the requirement for an external potentiostat to power and interpret the electrochemical measurement. New developments in paper-based electronics may help loosen this requirement. This review discusses the current capabilities and limitations of EμPADs and paper-based electronics, and sketches the ways in which these technologies can be combined to provide new devices for diagnostic testing.

When coupling capillary electrophoresis with postcolumn detection methods, such as mass spectrometry, the presence of postcolumn band broadening must be considered. The band broadening effects introduced by junction-at-the-tip CE-MS interfaces using a postcolumn micro flow-through vial are investigated by studying the hydrodynamic flow patterns and mass transport process inside the micro vial at the end of the CE separation capillary. Simulation results obtained by solving the Navier-Stokes and mass balance equations provide insights into the velocity field and concentration distribution of the analytes in the micro vial and demonstrate that, with a low flow rate of chemical modifier solution, the laminar flow streams confine the analyte molecules to the central part of the micro vial and thus maintain major features of the peak shapes. Peaks detected by UV and MS under similar experimental conditions were compared to verify the numerical prediction that the main features of the UV peak can be retained in the MS peak. Experiments also show that band broadening can be minimized when an appropriate chemical modifier flow rate is selected.

Two-dimensional electro-fluid-dynamic (EFD) devices, in which both electric field and hydrodynamic pressure are used to drive the analyte and fluid migration, enable two-dimensional channel networks to be used for chemical separation instead of one-dimensional column separation systems. Investigation of the theory of mass transfer in symmetrical Y-shaped EFD devices shows that the magnitude of pressure-induced velocity in lateral channels at critical boundary conditions between different steady state migration paths is independent of the channel cross-sectional area ratio. Therefore, the analyte has four possible mass transfer pathways according to the electric field and pressure setup in all symmetrical Y-shaped 2-D EFD devices, and such devices with any cross-sectional area ratio have the capacity to continuously purify two analytes from a mixture simultaneously. In addition, a new format of multiple-branched 2-D EFD devices is introduced to process multiple analytes. A "proof-reading" mechanism based on the infinite resolution conditions ensures the purity of the components collected. The separation processes are simulated by COMSOL Multiphysics, and the migration behavior of the analytes was monitored using fluorescent dyes to verify the flow behavior of different analytes in individual channels. These 2-D EFD devices offer the potential of continuous fractionation and purification of analytes from complex sample mixtures.

A method for adapting widely used CE conditions for the separation of fluorescently labeled carbohydrates to permit online ESI-MS detection is presented. Reverse polarity separations were performed in bare fused-silica capillaries with an acidic BGE. Under these conditions, negatively charged 8-aminopyrene 1,3,6-trisulfonate-labeled carbohydrates migrate forward against the EOF, which is towards the capillary inlet. Therefore, the CE-MS interface must simultaneously back-fill the capillary, in order to maintain the CE circuit, and provide a stable forward flow at the sprayer tip to support the electrospray process. This was achieved using a junction-at-the-tip interface, which provides a flow of solution to the junction formed by the capillary terminus and the inner wall of the emitter needle tip. Because the flow rate required for this arrangement is much less than in conventional sheath flow interfaces, dilution of the analytes is minimized. Optimized separation conditions permit baseline resolution of glucose oligomers containing up to 15 glucose units, while longer oligomers, up to 33 glucose units, were observed as resolved peaks in the negative ion mode mass spectrum.

A capillary electrophoresis mass spectrometry (CE-MS) interface utilizing a flow-through microvial is used to ensure the electric continuity and supply the catholyte and mobilizer solutions during the capillary isoelectric focusing (cIEF) and mobilization process. The flow-through microvial provides a stable chemical environment and helps to improve the ionization efficiency without significantly diluting the analyte. The CE-MS interface facilitates the transfer of the mobilized cIEF effluent to the site of electrospray ionization, and the gaseous ions can be detected directly by a mass spectrometer. It also allows for complete focusing and mobilization processes to be performed automatically in programmed sequences with commercial CE systems. Two different strategies, using either a part of the capillary or the flow-through microvial of the CE-MS interface as the catholyte reservoir for bare fused silica capillaries or neutral coated capillaries, respectively, were developed for automated cIEF-electrospray ionization (ESI)-MS. Reasonable separation efficiency was achieved using proper concentration of carrier ampholytes and suitable strategies of electroosmotic/electrophoretic mobilization.

Mixing of two solutions into one is a spontaneous process with a net increase in entropy. However, the reverse of the mixing process is usually not possible unless certain conditions are met. A continuous solution stream containing a mixture of two compounds can be separated into two channels, each containing a pure compound, thus reversing the mixing process using a two-dimensional microfluidic electro-fluid-dynamic (EFD) device. When the electric field is strategically applied in the interconnecting channels of an EFD device, the pressure required to direct an analyte into a certain channel can be calculated by using the solutions of electric field and fluid dynamics in the mass balance equation. If the pressure and electric potential at various inlets and outlets satisfy these predetermined conditions, the reverse of a mixing process is observed. Conventional microfluidic devices have been used to introduce samples from interconnecting channels or efficiently mix different solutions into a single channel. The EFD devices expand the spatial separation of analytes from one dimension to two using both the differential migration behavior of analytes and the velocity field distribution in different channel geometries. The devices designed according to these basic physicochemical principles can be used for complete processing of minute samples and to obtain pure chemical species from complex mixtures.

An interface for CE-ESI-MS that decouples both the electrical and the solution flow rate requirements of the separation and ionization processes is presented. The interface uses a tapered and beveled stainless steel hollow needle surrounding the separation capillary terminus so that the inside of the electrode acts as the CE outlet vial and the outside up acts as the electrospray emitter. No capillary pre-treatment is required, enabling the use of capillaries with any type of surface modification. A chemical modifier solution is Introduced through a second capillary connected to the needle via a tee)unction and can be used to improve the compatibility of the CE BGE with electrospray. The flow rate of modifier solution can be as low as 0 1 mu L/min, much less than that in a typical sheath-flow interface, thus minimizing dilution of the CE effluent in order to maximize sensitivity. The presence of the modifier solution also allows the use of neutral-coated capillaries for protein analysis by CE-MS without using an assisting pressure, despite the absence of EOF under these conditions The interface is easily integrated into a commercial CE instrument, such that all operations can be carried out by the automated controls. Compared with a commercial sheath-flow CE-MS interface operating under optimized conditions, LODs for amino acids were, on average, improved fivefold