Mechanistic Analysis of Peptide Affinity to Single-Walled Carbon Nanotubes and Volatile Organic Compounds Using Chemiresistors.

Peptides, due to their diverse and controllable properties, are used as both liquid and gas phase recognition elements for both biological and chemical targets. While it is well understood how binding of a peptide to a biomolecule can be converted into a sensing event, there is not the same mechanistic level of understanding with regard to how peptides modulate the selectivity of semiconductor/conductor-based gas sensors. Notably, a rational, mechanistic study has not yet been performed to correlate peptide properties to the sensor response for volatile organic compounds (VOCs) as a function of chemical properties.

Superlative and Selective Sensing of Serotonin in Undiluted Human Serum Using Novel Polystyrene Sulfonate Conductive Polymer.

In the past 5 years, real-time health monitoring has become ubiquitous with the development of watches and rings that can measure and report on the physiological state. As an extension, real-time biomarker sensors, such as the continuous glucose monitor, are becoming popular for both health and performance monitoring. However, few real-time sensors for biomarkers have been made commercially available; this is primarily due to problems with cost, stability, sensitivity, selectivity, and reproducibility of biosensors.

Rapid and Simple Buffer Exchange Using Cation-Exchange Chromatography to Improve Point-of-Care Detection of Pharmacological Agents.

The current COVID-19 pandemic has highlighted the power, speed, and simplicity of point-of-care (POC) diagnostics. POC diagnostics are available for a wide range of targets, including both drugs of abuse as well as performance-enhancing drugs. For pharmacological monitoring, minimally invasive fluids such as urine and saliva are commonly sampled.

Detection of Asthma Inhaler Use via Terahertz Spectroscopy.

Inhaled medications are commonplace for administering bronchodilators, anticholinergics, and corticosteroids. While they have a defined legitimate use, they are also used in sporting events as performance-enhancing drugs. These performance enhancers can be acquired via both legal (i.

A Strength Endurance Exercise Paradigm Mitigates Deficits in Hypoglossal-Tongue Axis Function, Strength, and Structure in a Rodent Model of Hypoglossal Motor Neuron Degeneration.

The tongue plays a crucial role in the swallowing process, and impairment can lead to dysphagia, particularly in motor neuron diseases (MNDs) resulting in hypoglossal-tongue axis degeneration (e.g., amyotrophic lateral sclerosis and progressive bulbar palsy).

Electrochemical biosensor for rapid detection of fungal contamination in fuel systems.

There is an increased demand for real-time monitoring of biological and biochemical processes. While most sensor research focuses on physiological conditions, less has been done towards developing real-time biosensors that can operate in and survive exposure to extreme environments and harsh chemicals such as fuel. One interesting application is monitoring microbial load in fuel tanks to prevent both fuel spoilage and biocorrosion.

Laser-Fabricated 2D Molybdenum Disulfide Electronic Sensor Arrays for Rapid, Low-Cost, Ultrasensitive Detection of Influenza A and SARS-Cov-2.

Multiplex electronic antigen sensors for detection of SARS-Cov-2 spike glycoproteins and hemagglutinin from influenza A are fabricated using scalable processes for straightforward transition to economical mass-production. The sensors utilize the sensitivity and surface chemistry of a 2D MoS transducer for attachment of antibody fragments in a conformation favorable for antigen binding with no need for additional linker molecules. To make the devices, ultra-thin layers (3 nm) of amorphous MoS are sputtered over pre-patterned metal electrical contacts on a glass chip at room temperature.

Distinguishing between recruitment and spread of silent chromatin structures in .

The formation of heterochromatin at , , and telomeres in involves two main steps: the recruitment of Sir proteins to silencers and their spread throughout the silenced domain. We developed a method to study these two processes at single basepair resolution. Using a fusion protein between the heterochromatin protein Sir3 and the nonsite-specific bacterial adenine methyltransferase M.

Biomarkers and Detection Platforms for Human Health and Performance Monitoring: A Review.

Human health and performance monitoring (HHPM) is imperative to provide information necessary for protecting, sustaining, evaluating, and improving personnel in various occupational sectors, such as industry, academy, sports, recreation, and military. While various commercially wearable sensors are on the market with their capability of "quantitative assessments" on human health, physical, and psychological states, their sensing is mostly based on physical traits, and thus lacks precision in HHPM. Minimally or noninvasive biomarkers detectable from the human body, such as body fluid (e.

A Dual Approach of an Oil-Membrane Composite and Boron-Doped Diamond Electrode to Mitigate Biofluid Interferences.

Electrochemical biosensors promise a simple method to measure analytes for both point-of-care diagnostics and continuous, wearable biomarker monitors. In a liquid environment, detecting the analyte of interest must compete with other solutes that impact the background current, such as redox-active molecules, conductivity changes in the biofluid, water electrolysis, and electrode fouling. Multiple methods exist to overcome a few of these challenges, but not a comprehensive solution.

Oil-Membrane Protection of Electrochemical Sensors for Fouling- and pH-Insensitive Detection of Lipophilic Analytes.

To take full advantage of the reagent- and label-free sensing capabilities of electrochemical sensors, a frequent and remaining challenge is interference and degradation of the sensors due to uncontrolled pH or salinity in the sample solution or foulants from the sample solution. Here, we present an oil-membrane sensor protection technique that allows for the permeation of hydrophobic (lipophilic) analytes into a sealed sensor compartment containing ideal salinity and pH conditions while simultaneously blocking common hydrophilic interferents (proteins, acids, bases, etc.) In this paper, we validate the oil-membrane sensor protection technique by demonstrating continuous cortisol detection via electrochemical aptamer-based (EAB) sensors.

Dynamic post-transcriptional regulation by Mrn1 links cell wall homeostasis to mitochondrial structure and function.

The RNA-binding protein Mrn1 in Saccharomyces cerevisiae targets over 300 messenger RNAs, including many involved in cell wall biogenesis. The impact of Mrn1 on these target transcripts is not known, however, nor is the cellular role for this regulation. We have shown that Mrn1 represses target mRNAs through the action of its disordered, asparagine-rich amino-terminus.

Discovery of Ketone-Based Covalent Inhibitors of Coronavirus 3CL Proteases for the Potential Therapeutic Treatment of COVID-19.

The novel coronavirus disease COVID-19 that emerged in 2019 is caused by the virus SARS CoV-2 and named for its close genetic similarity to SARS CoV-1 that caused severe acute respiratory syndrome (SARS) in 2002. Both SARS coronavirus genomes encode two overlapping large polyproteins, which are cleaved at specific sites by a 3C-like cysteine protease (3CL) in a post-translational processing step that is critical for coronavirus replication. The 3CL sequences for CoV-1 and CoV-2 viruses are 100% identical in the catalytic domain that carries out protein cleavage.

Analysis of pressure-driven membrane preconcentration for point-of-care assays.

Point-of-care diagnostic devices for both physicians and patients themselves are now ubiquitous, but often not sensitive enough for highly dilute analytes (e.g., pre-symptomatic viral detection).

Impact of Self-Assembled Monolayer Design and Electrochemical Factors on Impedance-Based Biosensing.

Real-time sensing of proteins, especially in wearable devices, remains a substantial challenge due to the need to convert a binding event into a measurable signal that is compatible with the chosen analytical instrumentation. Impedance spectroscopy enables real-time detection via either measuring electrostatic interactions or electron transfer reactions while simultaneously being amenable to miniaturization for integration into wearable form-factors. To create a more robust methodology for optimizing impedance-based sensors, additional fundamental studies exploring components influencing the design and implementation of these sensors are needed.

Evaluation of a standardized collection device for exhaled breath sampling onto thermal desorption tubes.

The Respiration Collector for In Vitro Analysis (ReCIVA) sampler, marketed by Owlstone Medical, provides a step forward in exhaled breath sampling through active sampling directly onto thermal desorption (TD) tubes. Although an improvement to the issues surrounding breath bag sampling, the ReCIVA device, first released in 2015, is a relatively new research and clinical tool that requires further exploration. Here, data are presented comparing two distinct ReCIVA devices.

Air2Liquid Method for Selective, Sensitive Detection of Gas-Phase Organophosphates.

Environmental hazards typically are encountered in the gaseous phase; however, selective sensing modalities for identifying and quantitating compounds of interest in an inexpensive, pseudo-real-time format are severely lacking. Here, we present a novel proof-of-concept that combines an Air2Liquid sampler in conjunction with an oil-in-water microfluidic assay for detection of organophosphates. We believe this proof-of-concept will enable development of a new platform technology for semivolatile detection that we have demonstrated to detect 50 pmoles (2 ppb) of neurotoxic organophosphates.

Characterization of standardized breath sampling for off-line field use.

Due to several sources of potential variability associated with exhaled breath bag sampling procedures for off-line analysis, the Respiration Collector for in vitro Analysis (ReCIVA) sampler was developed. Although designed to improve upon several pitfalls of sampling with exhaled breath bags, the ReCIVA remains a minimally studied research tool. In this manuscript, several attributes of the ReCIVA sampler are investigated among three individual tests, such as background contamination, control software version, performance of different adsorbent tubes, duplicate sample production, and comparison to exhaled breath bags.

Mutations in the PCNA DNA Polymerase Clamp of Reveal Complexities of the Cell Cycle and Ploidy on Heterochromatin Assembly.

In , transcriptional silencing at and maintains mating-type identity. The repressive chromatin structure at these loci is replicated every cell cycle and must be re-established quickly to prevent transcription of the genes at these loci. Mutations in a component of the replisome, the proliferating cell nuclear antigen (PCNA), encoded by , cause a loss of transcriptional silencing at We used an assay that captures transient losses of silencing at and to perform extended genetic analyses of the , , and alleles.

Achievements and Challenges for Real-Time Sensing of Analytes in Sweat within Wearable Platforms.

Physiological sensors in a wearable form have rapidly emerged on the market due to technological breakthroughs and have become nearly ubiquitous with the Apple Watch, FitBit, and other wearable devices. While these wearables mostly monitor simple biometric signatures, new devices that can report on the human readiness level through sensing molecular biomarkers are critical to optimizing the human factor in both commercial sectors and the Department of Defense. The military is particularly interested in real-time, wearable, minimally invasive monitoring of fatigue and human performance to improve the readiness and performance of the war fighter.

Continuous, quantifiable, and simple osmotic preconcentration and sensing within microfluidic devices.

Insurmountable detection challenges will impede the development of many of the next-generation of lab-on-a-chip devices (e.g., point-of-care and real-time health monitors).

Complete validation of a continuous and blood-correlated sweat biosensing device with integrated sweat stimulation.

A wearable sweat biosensing device is demonstrated that stimulates sweat and continuously measures sweat ethanol concentrations at 25 s intervals, which is then correlated with blood ethanol during a >3 hour testing phase. The testing involves a baseline condition (no ethanol) followed by a rapid blood and sweat rise of ethanol (oral bolus), and finally, the physiological response of the body as ethanol concentrations return to baseline (metabolized). Data sets include multiple in vivo validation trials and careful in vitro characterization of the electrochemical enzymatic ethanol sensor against likely interferents.

The dispersion-brightness relation for fast radio bursts from a wide-field survey.

Despite considerable efforts over the past decade, only 34 fast radio bursts-intense bursts of radio emission from beyond our Galaxy-have been reported. Attempts to understand the population as a whole have been hindered by the highly heterogeneous nature of the searches, which have been conducted with telescopes of different sensitivities, at a range of radio frequencies, and in environments corrupted by different levels of radio-frequency interference from human activity. Searches have been further complicated by uncertain burst positions and brightnesses-a consequence of the transient nature of the sources and the poor angular resolution of the detecting instruments.

Open nanofluidic films with rapid transport and no analyte exchange for ultra-low sample volumes.

Moving to ultra-low (<100 nL) sample volumes presents numerous challenges, many of which can be resolved by implementation of open nanofluidic films. These nanofluidic films are fabricated using a hexagonal network of gold-coated open microchannels which capture all of the following innovative advantages: (1) sample volumes of <100 nL cm-2; (2) zero analyte exchange and loss with the film materials; (3) rapid and omni-directional wicking transport of >500 nL min-1 per square of film; (4) ultra-simple roll-to-roll fabrication; (5) stable and bio-compatible super-hydrophilicity for weeks in air by peptide surface modification. Validation includes both detailed in vitro characterization and in vivo validation with sweat transport from the human skin.

Enhancing glucose flux into sweat by increasing paracellular permeability of the sweat gland.

Non-invasive wearable biosensors provide real-time, continuous, and actionable health information. However, difficulties detecting diluted biomarkers in excreted biofluids limit practical applications. Most biomarkers of interest are transported paracellularly into excreted biofluids from biomarker-rich blood and interstitial fluid during normal modulation of cellular tight junctions.