Ionophore-based nanosensors (IBNS) are tools that enable quantification of analytes in complex chemical and biological systems. IBNS methodology is adopted from that of bulk optodes where an ion exchange event is converted to a change in optical output. While valuable, an important aspect for application is the ability to intentionally tune their size with simple approaches, and ensure that they contain compounds safe for application. Lipidots are a platform of size tunable lipid nanoemulsions with a hydrophobic lipid core typically used for imaging and drug delivery. Here, we present LipiSensors as size tunable IBNS by exploiting the Lipidot model as a hydrophobic structural support for the sensing moieties that are traditionally encased in plasticized PVC nanoparticles. The LipiSensors we demonstrate here are sensitive and selective for calcium, reversible, and have a lifetime of approximately one week. By changing the calcium sensing components inside the hydrophobic core of the LipiSensors to those sensitive for oxygen, they are also able to be used as ratiometric O2 sensitive nanosensors via a quenching-based mechanism. LipiSensors provide a versatile, general platform nanosensing with the ability to directly tune the size of the sensors while including biocompatible materials as the structural support by merging sensing approaches with the Lipidot platform.
Traditional liquid phase extraction techniques that use optically responsive ligands provide benefits that enable cost-efficient and rapid measurements. However, these approaches have limitations in their excessive use of organic solvents and multistep procedures. Here, we developed a simple, nanoscale extraction approach by replacing the macroscopic organic phase with hydrophobic polymeric nanoparticles that are dispersed in an aqueous feed. The concentration of analytes in polymeric nanoparticle suspensions is governed by similar partition principles to liquid–liquid phase extraction techniques. By encasing optically responsive metal ligands inside polymeric nanoparticles, we introduce a one-step metal quantification assay based on traditional two-phase extraction methodologies. As an initial proof of concept, we encapsulated bathophenanthroline (BP) inside the particles to extract then quantify Fe 2+ with colorimetry in a dissolved supplement tablet and creek water. These Fe 2+ nanosensors are sensitive and selective and report out with fluorescence by adding a fluorophore (DiO) into the particle core. To show that this new rapid extraction assay is not exclusive to measuring Fe 2+ , we replaced BP with either 8-hydroxyquinoline or bathocuproine to measure Al 3+ or Cu + , respectively, in water samples. Utilizing this nanoscale extraction approach will allow users to rapidly quantify metals of interest without the drawbacks of larger-scale phase extraction approaches while also allowing for the expansion of phase extraction methodologies into areas of biological research.
A common biological theme on Earth is the importance of oxygen, regardless of an organism’s metabolic capabilities. This commonality makes the quantification of O2 essential in understanding life as we know it. There are many sensing methods that enable researchers to measure this important analyte, but not all sensors are compatible with every system. This perspective highlights common O2 sensing formats (and recent innovations) with the goal of guiding the reader toward a sensor choice for their desired application. We emphasize the importance of exploring unfamiliar metabolic processes, commercializing new sensors, and establishing collaborations for maximizing innovation and accelerating discovery.
Although it is estimated that more than one million Americans have celiac disease (CD), it remains challenging to diagnose. CD, an autoimmune and inflammatory response following the ingestion of gluten-containing foods, has symptoms overlapping with other diseases and requires invasive diagnostics. The gold standard for CD diagnosis involves serologic blood tests followed by invasive confirmatory biopsies. Here, we propose a less invasive method using an electrochemical DNA (E-DNA) biosensor for CD-specific autoantibodies (AABs) circulating in blood. In our approach, CD-specific AABs bind a synthetic neoepitope, causing a conformational change in the biosensor, as well as a change in the environment of an attached redox reporter, producing a measurable current reduction. We assessed the biosensor’s ability to detect CD-specific patient-derived AABs in physiological buffer as well as buffer supplemented with bovine serum. Our biosensor was able to detect AABs in a dose-dependent manner; increased signal change correlated with increased AAB concentration with an apparent dissociation constant of 0.09 ± 0.03 units/mL of AABs. Furthermore, we found our biosensor to be target-specific, with minimal off-target binding of multiple unrelated biomarkers. Future efforts aimed at increasing sensitivity in complex media may build upon the biosensor design presented here to further improve CD AAB detection and CD diagnostic tools.
Mycobacterium tuberculosis (M.tb) is one of the world’s most prevalent bacterial pathogens. However, Nontuberculous Mycobacterium (NTM) are less recognized than M.tb while remaining a pressing public health risk. Often, NTM lung disease is confused with that of a tubercle infection leading to unreliable diagnosis. Additionally, the time spent to fully diagnose a mycobacterial disease is extensive and dependent on the species growth rate due to the necessity of culturing for identification. Thus, designing a sensitive, electrochemical DNA‐based (E‐DNA) biosensor as a diagnostic tool for NTM would dramatically decrease the timeline of diagnosis and therefore could improve patient outcomes. In this work, we pursued detection of the cell envelope of NTM, which includes many complex glycolipids and glycopeptidolipids—many of which are believed to have immunopathogenic mechanisms. As mannose‐capped lipoarabinomannan (ManLAM) is one of the most prevalent of the glycolipids, we adapted it as a biomarker for the sensitive detection of NTM. An aptamer specific to ManLAM was incorporated into our E‐DNA biosensor, and exhibits significant current change under square wave voltammetric interrogation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.