Specific and Sensitive Determination of Folic Acid by Label-Free Chemosensors with Microscope Glass Slips as Single-Use Consumables

Abstract

Folic acid (FA) and its other forms known as folates are small molecules vital for humans. The high demand for increasingly sensitive methods of measuring folate concentrations is due to the fact that abnormal levels of FA cause severe health disorders. Besides, folates are used as recognition molecules in targeted drug delivery. The majority of FA measuring techniques are rather expensive, laborious, sometimes not sufficiently sensitive and specific, and often employ consumables that are too costly to be single-use for routine medical diagnostics. Here, we present a procedure for transformation of a simple microscope cover glass slip without deposition of any metal or dielectric films into a cost-efficient chemosensor chip interrogated by spectral correlation interferometry for highly sensitive measurements of the concentration of small molecules, as well as a feasibility study of long-term monitoring of such molecules in a flow mode. The obtained chips were tested for folate detection. The highly specific and sensitive measurements can be performed in real-time in a wide dynamic range of 0.9–220,000 pM. The developed method and single-use consumables are promising for concentration measurements of low molecular weight substances in pharmaceuticals and in vitro diagnostics.

Quantitative Rapid Magnetic Immunoassay for Sensitive Toxin Detection in Food: Non-Covalent Functionalization of Nanolabels vs. Covalent Immobilization

“…The initial series of experiments was conducted to investigate a crucial parameter influencing the analytical properties of immunosensors—namely, performed the kinetic characterization of monoclonal antibodies that recognize zearalenone (anti-ZEA Ab). For the purpose, their equilibrium and kinetic constants for association and dissociation with the target analyte were determined using the label-free methods of spectral-phase interferometry and spectral-correlation interferometry (see Section 4.2 of the Materials and Methods) [ 49 , 50 , 51 ]. Sensor chips were fabricated with conjugates of the carrier protein (BSA) and zearalenone immobilized on their surfaces.…”

“…The kinetic properties of the antibodies were assessed using the spectral-phase and spectral-correlation interferometry methods [ 49 , 50 , 51 , 57 ]. The experimental setup consists of an optical system based on low-coherence interferometry, a fluidic system, and digital equipment necessary for signal registration and analysis.…”

Super-Enhancers and Their Parts: From Prediction Efforts to Pathognomonic Status

“…Focusing on future research directions for SE investigation, there is a promising horizon where breakthroughs and evolving technologies could significantly enhance our grasp of SE complexities. Key areas of interest could include delving into the molecular bases of diseases, particularly cancer [ 283 , 284 , 285 , 286 , 287 ], probing molecular interactions with state-of-the-art optical methods [ 288 , 289 , 290 , 291 ], leveraging magnetic nanotags for the ultraprecise detection of biomolecules [ 292 , 293 , 294 , 295 , 296 , 297 , 298 , 299 ], applying advanced label-free biosensors [ 300 , 301 , 302 , 303 , 304 ], and utilizing cloud computing to analyse genome-wide data comprehensively [ 305 , 306 ]. These avenues not only promise to deepen our understanding of SE but also potentially redefine its conceptual framework.…”

Experimental Validation and Prediction of Super-Enhancers: Advances and Challenges

“…At the same time, according to some data, there is reason to believe that super-enhancers can be much more ancient, if compared exempli gratia with stress response proteins in multicellular organisms. It should be noted that advancements in understanding the molecular mechanisms of diseases (particularly oncological diseases [ 217 , 218 , 219 , 220 ]) as well as the study of intermolecular interactions through high-performance optical methods [ 221 , 222 , 223 ], the ultrasensitive determination of biomolecules using magnetic nanomarkers [ 224 , 225 , 226 , 227 ] or label-free biosensors [ 228 , 229 , 230 ], and the processing of genome-wide data through high-performance methods such as cloud computing [ 231 , 232 ] may provide new opportunities for comprehending the role of SEs, potentially leading to the revision of their definition.…”