Pixelated spatial gene expression analysis from tissue.

Here, we present a technique that performs on-chip picoliter real-time reverse transcriptase loop mediated isothermal amplification (RT-LAMP) reactions on a histological tissue section without any analyte purification while preserving the native spatial location of the nucleic acid molecules. We demonstrate this method by amplifying TOP2A messenger RNA (mRNA) in a prostate cancer xenograft with 100 µm spatial resolution and by visualizing the variation in threshold time of amplification across the tissue. The on-chip reaction was validated by mRNA fluorescence in situ hybridization (mFISH) from cells in the tissue section. The entire process, from tissue loading on microchip to results from RT-LAMP can be carried out in less than 2 h. We anticipate that this technique, with its ease of use, fast turnaround, and quantitative molecular outputs, would become an invaluable tissue analysis tool for researchers and clinicians in the biomedical arena.

Hands-free smartphone-based diagnostics for simultaneous detection of Zika, Chikungunya, and Dengue at point-of-care.

Infectious diseases remain the world's top contributors to death and disability, and, with recent outbreaks of Zika virus infections there has been an urgency for simple, sensitive and easily translatable point-of-care tests. Here we demonstrate a novel point-of-care platform to diagnose infectious diseases from whole blood samples. A microfluidic platform performs minimal sample processing in a user-friendly diagnostics card followed by real-time reverse-transcription loop-mediated isothermal amplification (RT-LAMP) on the same card with pre-dried primers specific to viral targets. Our point-of-care platform uses a commercial smartphone to acquire real-time images of the amplification reaction and displays a visual read-out of the assay. We apply this system to detect closely related Zika, Dengue (types 1 and 3) and Chikungunya virus infections from whole blood on the same pre-printed chip with high specificity and clinically relevant sensitivity. Limit of detection of 1.56e5 PFU/mL of Zika virus from whole blood was achieved through our platform. With the ability to quantitate the target nucleic acid, this platform can also perform point-of-care patient surveillance for pathogen load or select biomarkers in whole blood.

A microfluidic biochip for complete blood cell counts at the point-of-care.

Complete blood cell counts (CBCs) are one of the most commonly ordered and informative blood tests in hospitals. The results from a CBC, which typically include white blood cell (WBC) counts with differentials, red blood cell (RBC) counts, platelet counts and hemoglobin measurements, can have implications for the diagnosis and screening of hundreds of diseases and treatments. Bulky and expensive hematology analyzers are currently used as a gold standard for acquiring CBCs. For nearly all CBCs performed today, the patient must travel to either a hospital with a large laboratory or to a centralized lab testing facility. There is a tremendous need for an automated, portable point-of-care blood cell counter that could yield results in a matter of minutes from a drop of blood without any trained professionals to operate the instrument. We have developed microfluidic biochips capable of a partial CBC using only a drop of whole blood. Total leukocyte and their 3-part differential count are obtained from 10 µL of blood after on-chip lysing of the RBCs and counting of the leukocytes electrically using microfabricated platinum electrodes. For RBCs and platelets, 1 µL of whole blood is diluted with PBS on-chip and the cells are counted electrically. The total time for measurement is under 20 minutes. We demonstrate a high correlation of blood cell counts compared to results acquired with a commercial hematology analyzer. This technology could potentially have tremendous applications in hospitals at the bedside, private clinics, retail clinics and the developing world.