Sample-to-answer detection of miRNA from whole blood using thermally responsive alkane partitions.

Circulating miRNA offers a tremendous opportunity as a biomarker paradigm for many applications in disease diagnostics, including point-of-care diagnostics for global health needs. However, despite the numerous miRNA detection schemes reported, there still does not exist a solution for highly sensitive sample-to-answer detection of miRNA directly from complex samples, such as whole blood. We recently developed thermally responsive alkane partitions (TRAPs), which - when combined with magnetic microbeads - enable the complete assay automation from whole blood.

Saliva-STAT: Sample-to-answer saliva test for COVID-19.

Highly accessible and highly accurate diagnostics are necessary to combat rapidly-spreading infectious diseases, such as the recent COVID-19 pandemic. While lateral flow antigen tests have become pervasive, they are insufficiently sensitive to detect early or asymptomatic disease. Nucleic acid amplification tests provide the needed sensitivity, but accessibility of these tests continues to be a challenge due to the need for precise sample processing steps.

Sample-to-Answer Detection of SARS-CoV-2 Viremia Using Thermally Responsive Alkane Partitions.

The diagnosis of bloodborne viral infections (viremia) is currently relegated to central laboratories because of the complex procedures required to detect viruses in blood samples. The development of point-of-care diagnostics for viremia would enable patients to receive a diagnosis and begin treatment immediately instead of waiting days for results. Point-of-care systems for viremia have been limited by the challenges of integrating multiple precise steps into a fully automated (i.

Sample-to-Answer Immuno-Magnetic Assay Using Thermally Responsive Alkane Partitions.

To combat pandemics, there is a need for rapid point-of-care diagnostics to identify infected patients and to track the spread of the disease. While recent progress has been made in response to COVID-19, there continues to be a need for point-of-care diagnostics capable of detecting biomarkers-such as antibodies-in whole blood. We have recently reported the development of thermally responsive alkane partitions (TRAPs) for the automation of point-of-care immuno-magnetic assays.

Thermally Responsive Alkane Partitions for Assay Automation.

For point-of-care diagnostic tools to be impactful, they must be inexpensive, equipment-free, and sample-to-answer (i.e., require no user intervention).

Advances in the analysis of single extracellular vesicles: A critical review.

There is an ever-growing need for new cancer diagnostic approaches that provide earlier diagnosis as well as richer diagnostic, prognostic, and resistance information. Extracellular vesicles (EVs) recovered from a liquid biopsy have paradigm-shifting potential to offer earlier and more complete diagnostic information in the form of a minimally invasive liquid biopsy. However, much remains unknown about EVs, and current analytical approaches are unable to provide precise information about the contents and source of EVs.

Sample-to-Answer Diagnostic System for the Detection of Circulating Histones in Whole Blood.

Severe internal trauma results in millions of hospitalizations each year, including thousands of deaths caused by subsequent multiple organ failure. The majority of these deaths occur within the first 24 h, and thus, rapid diagnosis of internal trauma severity is necessary for immediate treatment. For early organ damage identification, diagnosis in point-of-care settings is crucial for rapid triage and treatment.

A critical review of point-of-care diagnostic technologies to combat viral pandemics.

The COVID-19 global pandemic of 2019-2020 pointedly revealed the lack of diagnostic solutions that are able to keep pace with the rapid spread of the virus. Despite the promise of decades of lab-on-a-chip research, no commercial products were available to deliver rapid results or enable testing in the field at the onset of the pandemic. In this critical review, we assess the current state of progress on the development of point-of-care technologies for the diagnosis of viral diseases that cause pandemics.

Phenotypically distinguishing ESBL-producing pathogens using paper-based surface enhanced Raman sensors.

Antimicrobial stewardship practices are critical in preventing the further erosion of treatment options for bacterial infections. Yet, at the same time, determination of an infection's antimicrobial susceptibility requires multiple rounds of culture and expensive lab automation systems. In this work, we report the use of paper-based surface enhanced Raman spectroscopy (SERS) sensors and portable instrumentation to phenotypically discriminate multi-drug resistance with fewer culture steps than conventional clinical microbiology.

Nucleic acid-cleaving catalytic DNA for sensing and therapeutics.

DNAzymes with nucleic acid-cleaving catalytic activity are increasing in versatility through concerted efforts to discover new sequences with unique functions, and they are generating excitement in the sensing community as cheap, stable, amplifiable detection elements. This review provides a comprehensive list and detailed descriptions of the DNAzymes identified to date, classified by their associated small molecule or ion needed for catalysis; of note, this classification clarifies conserved regions of various DNAzymes that are not obvious in the literature. Furthermore, we detail the breadth of functionality of these DNA sequences as well as the range of reaction conditions under which they are useful.

New Trimodal Phenotypic Reporter of Extended-Spectrum β-Lactamase Activity.

Bacterial resistance to β-lactam antibiotics continues to grow as misadministration presents evolutionary pressure that drives bacteria to develop improved resistance enzymes. Known as extended-spectrum β-lactamases (ESBLs), these enzymes are capable of hydrolyzing advanced β-lactam antibiotics such as third-generation (and higher) cephalosporins. Phenotypic detection substrates can be used to rapidly identify a cultured patient sample prior to confirmation by more exhaustive but slower means, critically aiding in the antibiotic stewardship essential in maintaining the effectiveness of not only the cephalosporins but also indirectly the carbapenems, our last-resort β-lactams.

Demonstration of a quantitative triplex LAMP assay with an improved probe-based readout for the detection of MRSA.

As molecular diagnostics move away from polymerase chain reaction (PCR) in order to target point-of-care testing applications, loop-mediated isothermal amplification (LAMP) is gaining popularity due its rapid, sensitive and specific detection with simpler instrumentation. However, while Taqman PCR enables real-time quantitative readout and multiplexed gene detection in single samples, analogous methods in LAMP are not yet broadly developed. To date, the real-time detection methods applied to LAMP involve turbidimetry or measuring fluorescence of an intercalator; however, both of these methods are nonspecific to the target of interest and do not allow for multiple gene detection in a single sample.

A critical review of flexible and porous SERS sensors for analytical chemistry at the point-of-sample.

For decades surface enhanced Raman spectroscopy (SERS) has been intensely investigated as a possible solution for performing analytical chemistry at the point of sample origin. Unfortunately, due to cost and usability constraints, conventional rigid SERS sensors and microfluidic SERS sensors have yet to make a significant impact outside of the realm of academics. However, the recently introduced flexible and porous paper-based SERS sensors are proving to be widely adaptable to realistic usage cases in the field.

Multistage Chemical Heating for Instrument-Free Biosensing.

Improving the portability of diagnostic medicine is crucial for alleviating global access-to-care deficiencies. This requires not only designing devices that are small and lightweight, but also autonomous and independent of electricity. Here, we present a strategy for conducting automated multistep diagnostic assays using chemically generated, passively regulated heat.

Phase-Change Partitions for Thermal Automation of Multistep Reactions.

Medical diagnostics and basic research in low-resource settings require automated reactions to be controlled in a simple, portable manner. Here, we present a novel platform that enables simple automation of multistep reactions to facilitate robust, hands-free assay operation without complex microfluidics or paperfluidics. We separate reagent zones in a conventional PCR tube via solid layers of purified higher alkanes.

Peroxidyme-Amplified Radical Chain Reaction (PARCR): Visible Detection of a Catalytic Reporter.

Peroxidyme Amplified Radical Chain Reaction (PARCR), a novel enzyme-free system that achieves exponential amplification of a visible signal, is presented. Typical enzyme-free amplification systems that produce a visible readout suffer from long reaction times, low sensitivity, and narrow dynamic range. PARCR employs photocatalyzed nonlinear signal generation, enabling unprecedented one-pot, naked-eye detection of a catalytic reporter from 1 μm down to 100 pm.

Inkjet-Printed Paper Fluidic Devices for Onsite Detection of Antibiotics Using Surface-Enhanced Raman Spectroscopy.

Surface enhanced Raman spectroscopy (SERS) provides rapid and sensitive identification of small molecule analytes. Traditionally, fabrication of SERS devices is an expensive process that involves the use of micro- and nano-fabrication procedures. Further, acquisition of diverse sample types requires complex preparation procedures that limits SERS to lab-based applications.

Simplifying Nucleic Acid Amplification from Whole Blood with Direct Polymerase Chain Reaction on Chitosan Microparticles.

Tremendous advances have been made in the development of portable nucleic acid amplification devices for near-patient use. However, the true limitation in the realization of nucleic acid amplification tests (NAATs) for near-patient applications is not the amplification reaction, it is the complexity of the sample preparation. Conventional approaches require several precise intervention steps during the protocol.

Vertical-flow paper SERS system for therapeutic drug monitoring of flucytosine in serum.

A number of life-saving drugs require therapeutic drug monitoring (TDM) for safe and effective use. Currently, however, TDM is performed using sophisticated analytical techniques relegated to central labs, increasing the cost per test and time to answer. Here, using a novel vertical flow membrane system with inkjet-printed surface enhanced Raman sensors, along with a portable spectrometer, we demonstrate a low cost and easy to use device to quantify levels of flucytosine, an antifungal that requires TDM for effective patient care, from undiluted human serum.

Capture and Direct Amplification of DNA on Chitosan Microparticles in a Single PCR-Optimal Solution.

While nucleic acid amplification tests have great potential as tools for rapid diagnostics, complicated sample preparation requirements inhibit their use in near-patient diagnostics and low-resource-setting applications. Recent advancements in nucleic acid purification have leveraged pH-modulated charge switching polymers to reduce the number of steps required for sample preparation. The polycation chitosan (pKa 6.

Higher phylogeny of frugivorous flies (Diptera, Tephritidae, Dacini): localised partition conflicts and a novel generic classification.

The phylogenetic relationships within and among subtribes of the fruit fly tribe Dacini (Ceratitidina, Dacina, Gastrozonina) were investigated by sequencing four mitochondrial and one nuclear gene fragment. Bayesian, maximum likelihood and maximum parsimony analyses were implemented on two datasets. The first, aiming at obtaining the strongest phylogenetic signal (yet, having lower taxon coverage), consisted of 98 vouchers and 2338 concatenated base pairs (bp).

Assessment of surfactants for efficient droplet PCR in mineral oil using the pendant drop technique.

Amplification and detection of nucleic acid sequences within integrated microsystems is routinely conducted using the technique of droplet PCR, wherein the polymerase chain reaction (PCR) is performed in microscale water-in-oil droplets (nanoliter to picoliter volumes). During droplet PCR, interactions at the interface of the droplet tend to dominate. Specifically, adsorption of the polymerase at the droplet interface leads to inefficient amplification.

Fabrication of rigid microstructures with thiol-ene-based soft lithography for continuous-flow cell lysis.

In this work, we introduce a method for the soft-lithography-based fabrication of rigid microstructures and a new, simple bonding technique for use as a continuous-flow cell lysis device. While on-chip cell lysis techniques have been reported previously, these techniques generally require a long on-chip residence time, and thus cannot be performed in a rapid, continuous-flow manner. Microstructured microfluidic devices can perform mechanical lysis of cells, enabling continuous-flow lysis; however, rigid silicon-based devices require complex and expensive fabrication of each device, while polydimethylsiloxane (PMDS), the most common material used for soft lithography fabrication, is not rigid and expands under the pressures required, resulting in poor lysis performance.

Detection of deoxyribonucleic acid (DNA) targets using polymerase chain reaction (PCR) and paper surface-enhanced Raman spectroscopy (SERS) chromatography.

Surface-enhanced Raman spectroscopy (SERS) enables multiplex detection of analytes using simple, portable equipment consisting of a single excitation source and detector. Thus, in theory, SERS is ideally suited to replace fluorescence in assays that screen for numerous deoxyribonucleic acid (DNA) targets, but in practice, SERS-based assays have suffered from complexity and elaborate processing steps. Here, we report an assay in which a simple inkjet-fabricated plasmonic paper device enables SERS-based detection of multiple DNA targets within a single polymerase chain reaction (PCR).

Reversible gelation of cells using self-assembling hydrophobically-modified biopolymers: towards self-assembly of tissue.

Polymer hydrogels have long been used to hold and culture biological cells within their three-dimensional (3-D) matrices. Typically, in such cases, the cells are passively entrapped in a mesh of polymer chains. Here, we demonstrate an alternate approach where cells serve as active structural elements (crosslinks) within a polymer gel network.