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Chemosensors ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 199
Anna Wcisło ◽  
Izabela Małuch ◽  
Paweł Niedziałkowski ◽  
Tadeusz Ossowski ◽  
Adam Prahl

Efficient deposition of biomolecules on the surface, maintaining their full activity and stability, is a most significant factor in biosensor construction. For this reason, more and more research is focused on the development of electrochemical biosensors that have the ability to electrically detect adsorbed molecules on electrode surface with high selectivity and sensitivity. The presented research aims to develop an efficient methodology that allows quantification of processes related to the evaluation of enzyme activity (proprotein convertase) using electrochemical methods. In this study we used impedance spectroscopy to investigate the immobilization of peptide substrate (Arg-Val-Arg-Arg) modified with 11-mercaptoundecanoic acid on the surface of gold electrode. Both the synthesis of the peptide substrate as well as the full electrochemical characteristics of the obtained electrode materials have been described. Experimental conditions, including concentration of peptide substrate immobilization, modification time, linker, and the presence of additional blocking groups have been optimized. The main advantages of the described method is that it makes it possible to observe the peptide substrate–enzyme interaction without the need to use fluorescent labels. This also allows observation of this interaction at a very low concentration. Both of these factors make this new technique competitive with the standard spectrofluorimetric method.

2021 ◽  
pp. 2101333
Mengji Zhang ◽  
Lin Huang ◽  
Jing Yang ◽  
Wei Xu ◽  
Haiyang Su ◽  

2021 ◽  
priyanka dutta ◽  
Vikas sharma ◽  
Hema bhardwaj ◽  
ved varun agrawal ◽  
Rajesh nil ◽  

Abstract A label-free electrochemical biosensor has been developed using Zinc Oxide nanoflowers (ZnONFs) for the detection of Uric acid. ZnONFs have been synthesized by hydrothermal process and characterized with several techniques such as Ultraviolet-Visible spectroscopy, Fourier Transform Infrared Spectroscopy (FT-IR) study, X-ray diffraction study, Raman spectroscopy, Scanning Electron Microscopy and High-Resolution Transmission Electron Microscopy (HR-TEM) and electrochemical analyser to confirms the formation of nanoflowers and fabrication of electrode and bioelectrodes for uric acid detection. Pure and uniform needle flowers and deposited onto Indium Tin Oxide (ITO) substrate through electrophoretic deposition technique. Further, electrochemical studies have been performed with immobilized enzymatic bioelectrode followed by various uric acid concentrations. It has been found that the fabricated biosensor shows high sensitivity (10.38 µA/ mg/mL /cm2) and a limit of detection of 0.13 mg/mL in the range of 0.005 to 1.0 mg/mL. This study demonstrates the potential use of ZnONFs for the construction of overly sensitive biosensors for Uric acid detection.

Christoph Bernhard ◽  
Marc-Jan van Zadel ◽  
Alexander Bunn ◽  
Mischa Bonn ◽  
Grazia Gonella

2021 ◽  
Vol 15 ◽  
Md. Mahmudul Hasan ◽  
Mst. Afsana Mimi ◽  
Md. Al Mamun ◽  
Ariful Islam ◽  
A. S. M. Waliullah ◽  

Glycans are diverse structured biomolecules that play crucial roles in various biological processes. Glycosylation, an enzymatic system through which various glycans are bound to proteins and lipids, is the most common and functionally crucial post-translational modification process. It is known to be associated with brain development, signal transduction, molecular trafficking, neurodegenerative disorders, psychopathologies, and brain cancers. Glycans in glycoproteins and glycolipids expressed in brain cells are involved in neuronal development, biological processes, and central nervous system maintenance. The composition and expression of glycans are known to change during those physiological processes. Therefore, imaging of glycans and the glycoconjugates in the brain regions has become a “hot” topic nowadays. Imaging techniques using lectins, antibodies, and chemical reporters are traditionally used for glycan detection. However, those techniques offer limited glycome detection. Mass spectrometry imaging (MSI) is an evolving field that combines mass spectrometry with histology allowing spatial and label-free visualization of molecules in the brain. In the last decades, several studies have employed MSI for glycome imaging in brain tissues. The current state of MSI uses on-tissue enzymatic digestion or chemical reaction to facilitate successful glycome imaging. Here, we reviewed the available literature that applied MSI techniques for glycome visualization and characterization in the brain. We also described the general methodologies for glycome MSI and discussed its potential use in the three-dimensional MSI in the brain.

2021 ◽  
Vol 12 (1) ◽  
Jan N. Hansen ◽  
An Gong ◽  
Dagmar Wachten ◽  
René Pascal ◽  
Alex Turpin ◽  

AbstractMany biological processes happen on a nano- to millimeter scale and within milliseconds. Established methods such as confocal microscopy are suitable for precise 3D recordings but lack the temporal or spatial resolution to resolve fast 3D processes and require labeled samples. Multifocal imaging (MFI) allows high-speed 3D imaging but is limited by the compromise between high spatial resolution and large field-of-view (FOV), and the requirement for bright fluorescent labels. Here, we provide an open-source 3D reconstruction algorithm for multi-focal images that allows using MFI for fast, precise, label-free tracking spherical and filamentous structures in a large FOV and across a high depth. We characterize fluid flow and flagellar beating of human and sea urchin sperm with a z-precision of 0.15 µm, in a volume of 240 × 260 × 21 µm, and at high speed (500 Hz). The sampling volume allowed to follow sperm trajectories while simultaneously recording their flagellar beat. Our MFI concept is cost-effective, can be easily implemented, and does not rely on object labeling, which renders it broadly applicable.

2021 ◽  
Vol 12 (1) ◽  
Tongcheng Qian ◽  
Tiffany M. Heaster ◽  
Angela R. Houghtaling ◽  
Kexin Sun ◽  
Kayvan Samimi ◽  

AbstractHuman pluripotent stem cell (hPSC)-derived cardiomyocytes provide a promising regenerative cell therapy for cardiovascular patients and an important model system to accelerate drug discovery. However, cost-effective and time-efficient platforms must be developed to evaluate the quality of hPSC-derived cardiomyocytes during biomanufacturing. Here, we develop a non-invasive label-free live cell imaging platform to predict the efficiency of hPSC differentiation into cardiomyocytes. Autofluorescence imaging of metabolic co-enzymes is performed under varying differentiation conditions (cell density, concentration of Wnt signaling activator) across five hPSC lines. Live cell autofluorescence imaging and multivariate classification models provide high accuracy to separate low (< 50%) and high (≥ 50%) differentiation efficiency groups (quantified by cTnT expression on day 12) within 1 day after initiating differentiation (area under the receiver operating characteristic curve, 0.91). This non-invasive and label-free method could be used to avoid batch-to-batch and line-to-line variability in cell manufacturing from hPSCs.

2021 ◽  
Vol 20 (1) ◽  
Médéric Loyez ◽  
Mathilde Wells ◽  
Stéphanie Hambÿe ◽  
François Hubinon ◽  
Bertrand Blankert ◽  

Abstract Background Early malaria diagnosis and its profiling require the development of new sensing platforms enabling rapid and early analysis of parasites in blood or saliva, aside the widespread rapid diagnostic tests (RDTs). Methods This study shows the performance of a cost-effective optical fiber-based solution to target the presence of Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Unclad multimode optical fiber probes are coated with a thin gold film to excite Surface Plasmon Resonance (SPR) yielding high sensitivity to bio-interactions between targets and bioreceptors grafted on the metal surface. Results Their performances are presented in laboratory conditions using PBS spiked with growing concentrations of purified target proteins and within in vitro cultures. Two probe configurations are studied through label-free detection and amplification using secondary antibodies to show the possibility to lower the intrisic limit of detection. Conclusions As malaria hits millions of people worldwide, the improvement and multiplexing of this optical fiber technique can be of great interest, especially for a future purpose of using multiple receptors on the fiber surface or several coated-nanoparticles as amplifiers.

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