Internet-enabled lab-on-a-chip technology for education.

Despite many interventions, science education remains highly inequitable throughout the world. Internet-enabled experimental learning has the potential to reach underserved communities and increase the diversity of the scientific workforce. Here, we demonstrate the use of lab-on-a-chip (LoC) technologies to expose Latinx life science undergraduate students to introductory concepts of computer programming by taking advantage of open-loop cloud-integrated LoCs. We developed a context-aware curriculum to train students at over 8000 km from the experimental site. Through this curriculum, the students completed an assignment testing bacteria contamination in water using LoCs. We showed that this approach was sufficient to reduce the students' fear of programming and increase their interest in continuing careers with a computer science component. Altogether, we conclude that LoC-based internet-enabled learning can become a powerful tool to train Latinx students and increase the diversity in STEM.

Dual optofluidic distributed feedback dye lasers for multiplexed biosensing applications.

Integrated optofluidic devices have become subjects of high interest for rapid biosensor devices due to their unique ability to combine the fluidic processing of small volumes of microfluidics with the analysis capabilities of photonic structures. By integrating dynamically reconfigurable optofluidic lasers on-chip, complex coupling can be eliminated while further increasing the capabilities of sensors to detect an increasing number of target biomarkers. Here, we report a polydimethylsiloxane-based device with two on-chip fluidic distributed feedback (DFB) laser cavities that are integrated with an orthogonal analyte channel for multiplexed fluorescence excitation. One DFB grating is filled with 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran dissolved in dimethyl sulfoxide. The second grating is filled with rhodamine 6G dissolved in a diluted ethylene glycol solution. We present characterization of both lasers through analysis of the lasing spectra for spectral narrowing along with a power series to observe threshold behavior. We then demonstrate simultaneous detection of two different fluorescent microbeads as a proof of concept for scalable, single biomarker analysis using on-chip optofluidic lasers.

Open-loop lab-on-a-chip technology enables remote computer science training in Latinx life sciences students.

Despite many interventions, science education remains highly inequitable throughout the world. Among all life sciences fields, Bioinformatics and Computational Biology suffer from the strongest underrepresentation of racial and gender minorities. Internet-enabled project-based learning (PBL) has the potential to reach underserved communities and increase the diversity of the scientific workforce. Here, we demonstrate the use of lab-on-a-chip (LoC) technologies to train Latinx life science undergraduate students in concepts of computer programming by taking advantage of open-loop cloud-integrated LoCs. We developed a context-aware curriculum to train students at over 8,000 km from the experimental site. We showed that this approach was sufficient to develop programming skills and increase the interest of students in continuing careers in Bioinformatics. Altogether, we conclude that LoC-based Internet-enabled PBL can become a powerful tool to train Latinx students and increase the diversity in STEM.

All-in-One Optofluidic Chip for Molecular Biosensing Assays.

Integrated biosensor platforms have become subjects of high interest for consolidated assay preparation and analysis to reduce sample-to-answer response times. By compactly combining as many biosensor processes and functions as possible into a single lab-on-chip device, all-in-one point-of-care devices can aid in the accessibility and speed of deployment due to their compact size and portability. Biomarker assay preparation and sensing are functionalities that are often carried out on separate devices, thus increasing opportunity of contamination, loss of sample volume, and other forms of error. Here, we demonstrate a complete lab-on-chip system combining sample preparation, on-chip optofluidic dye laser, and optical detection. We first show the integration of an on-chip distributed feedback dye laser for alignment-free optical excitation of particles moving through a fluidic channel. This capability is demonstrated by using Rhodamine 6G as the gain medium to excite single fluorescent microspheres at 575 nm. Next, we present an optofluidic PDMS platform combining a microvalve network (automaton) for sample preparation of nanoliter volumes, on-chip distributed feedback dye laser for target excitation, and optical detection. We conduct concurrent capture and fluorescence tagging of Zika virus nucleic acid on magnetic beads in 30 min. Target-carrying beads are then optically excited using the on-chip laser as they flow through an analysis channel, followed by highly specific fluorescence detection. This demonstration of a complete all-in-one biosensor is a tangible step in the development of a rapid, point-of-care device that can assist in limiting the severity of future outbreaks.

Pneumatically tunable optofluidic DFB dye laser using corrugated sidewalls.

Polydimethylsiloxane-based optofluidics provides a powerful platform for a complete analytical lab-on-chip. Here, we report on a novel on-chip laser source that can be integrated with sample preparation and analysis functions. A corrugated sidewall structure is integrated into a microfluidic channel to form a distributed feedback (DFB) laser using rhodamine 6G dissolved in an ethylene glycol and water solution. Lasing is demonstrated with a threshold pump power of 87.9 µW, corresponding to a pump intensity of 52.7mW/cm2. Laser threshold and output power are optimized with respect to rhodamine 6G concentration and core index and found to be in good agreement with a rate equation model. Additionally, the laser can be switched on and off mechanically using a pneumatic cell inducing positive pressure on the grating.

Two-dimensional combination of eight ultrashort pulsed beams using a diffractive optic pair.

We demonstrate, to the best of our knowledge, the first two-dimensional diffractive beam combination for ultrashort pulses-a highly scalable technique capable of using a diffractive optic pair to combine large arrays of ultrashort pulsed beams. A square array of eight 120 fs pulsed beams from eight fiber outputs is coherently combined into one beam using the diffractive combiner. The experimental results show that the combined pulse preserves the input pulse width and shape, and the combining efficiency is measured to be close to the limit of the manufactured diffractive optic. An analysis shows that the combining loss due to uncompensated temporal and spatial dispersions is negligible.

Coherent combination of ultrashort pulse beams using two diffractive optics.

A novel coherent beam combiner, capable of combining large numbers of femtosecond pulse beams using two diffractive optics, is presented. The diffractive optic pair cancels pulse front tilt, while uncorrected dispersions are minimized. An example using four beams is modeled numerically and tested experimentally, demonstrating 120 fs pulses combined without degradation of pulse width. Scaling the concept, we show analytically that combining loss due to uncorrected dispersions is only a few percent for ∼200 beams with 130 fs pulses.