Tag Archive for: immunosensor

Publication on AWSensors technology

C60-based Multivalent Glycoporphyrins Inhibit SARS-CoV-2 Specific Interaction with the DC-SIGN Transmembrane Receptor

/in , , /by

Authors: Jennifer Patino-Alonso, Justo Cabrera-González, Javier Merino, Gema Nieto-Ortiz, Fátima Lasala, Jouma Katati, Carlos H. Bezerra da Cruz, Ajay K. Monnappa, Pablo Mateos-Gil, Ángeles Canales, Iván López-Montero, Beatriz M. Illescas, Rafael Delgado, and Nazario Martín

Journal: Small (2023)

 

Abstract

Since WHO has declared the COVID-19 outbreak a global pandemic, nearly seven million deaths have been reported. This efficient spread of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is facilitated by the ability of the spike glycoprotein to bind multiple cell membrane receptors. Although ACE2 is identified as the main receptor for SARS-CoV-2, other receptors could play a role in viral entry. Among others, C-type lectins such as DC-SIGN are identified as efficient trans-receptor for SARS-CoV-2 infection, so the use of glycomimetics to inhibit the infection through the DC-SIGN blockade is an encouraging approach. In this regard, multivalent nanostructures based on glycosylated [60]fullerenes linked to a central porphyrin scaffold have been designed and tested against DC-SIGN-mediated SARS-CoV-2 infection. First results show an outstanding inhibition of the trans-infection up to 90%. In addition, a deeper understanding of nanostructure-receptor binding is achieved through microscopy techniques, high-resolution NMR experiments, Quartz Crystal Microbalance experiments, and molecular dynamic simulations.

You may read the full paper here.

Publication on AWSensors technology

Surface Acoustic Wave Immunosensor for Detection of Botulinum Neurotoxin

/in , , /by

Authors: Michał Grabka, Krzysztof Jasek and Zygfryd Witkiewicz

Journal: Sensors (2023)

 

Abstract

A Love-type acoustic wave sensor (AT-cut quartz substrate, SiO2 guiding layer) with a center frequency of approximately 120 MHz was used to detect a simulant of pathogenic botulinum neurotoxin type A—recombinant of BoNT-A light chain—in liquid samples. The sensor was prepared by immobilizing monoclonal antibodies specific for botulinum neurotoxin via a thiol monolayer deposited on a gold substrate. Studies have shown that the sensor enables selective analyte detection within a few minutes. In addition, the sensor can be used several times (regeneration of the sensor is possible using a low pH buffer). Nevertheless, the detectability of the analyte is relatively low compared to other analytical techniques that can be used for rapid detection of botulinum neurotoxin. The obtained results confirm the operation of the proposed sensor and give hope for further development of this label-free technique for detecting botulinum neurotoxin.

Surface Acoustic Wave (Love-SAW) immunosensor for detection of botulinum neurotoxin. Source: Sensors 2023, 23(18), 7688

You may read the full paper here.

Publication on AWSensors technology

High Fundamental Frequency (HFF) Monolithic Quartz Crystal Microbalance with Dissipation Array for the Simultaneous Detection of Pesticides and Antibiotics in Complex Food

/in , , /by

Authors: María Calero, Román Fernández, María García, Marisol Juan-Borrás, Isabel Escriche, Antonio Arnau, Ángel Montoya and Yolanda Jiménez.

Journal: Biosensors (2022)

 

Abstract

As in the case of the food industry in general, there is a global concern about safety and quality in complex food matrices, such as honey, which is driving the demand for fast, sensitive and affordable analytical techniques across the honey-packaging industry. Although excellent techniques such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) are available, these are located in centralized laboratories and are still lacking in speed, simplicity and cost-effectiveness. Here, a new approach is presented where a competitive immunoassay is combined with a novel High Fundamental Frequency Quartz Crystal Microbalance with Dissipation (HFF-QCMD) array biosensor for the simultaneous detection of antibiotics and pesticides in honey. Concretely, thiabendazole and sulfathiazole residues were monitored in spiked honey samples. Results revealed that HFF-QCMD arrays provide a complementary and reliable tool to LC-MS/MS for the analysis of contaminants in these kinds of complex matrices, while avoiding elaborate sample pre-treatment. The good sensitivity achieved (I50 values in the 70–720 µg/kg range) and the short analysis time (60 min for 24 individual assays), together with the ability for multiple analyte detection (24 sensor array) and its cost-effectiveness, pave the way for the implementation of a fast on-line, in situ routine control of potentially hazardous chemical residues in honey.

QCMD array cartridge microfluidics

You may read the full paper here.

QCMD webinar

QCM-D Webinar

/in , /by

May 24th 2021: AWSensors is pleased to invite you to participate in a QCM-D Scientific Webinar its Distributor Technex, in the BENELUX area, and AWSensors are orginizing. The scientific talk is entitled “Studying Soft Interfaces with Shear Waves: Principles and Applications of the Quartz Crystal Microbalance (QCM-D)” and  will be given by Prof. Diethelm Johannsmann.

 

QCMD Webinar

QCM-D Webinar details

The webinar will take place on Thursday, June 10th, 2021 from 15:00 to 16:30 hrs and it will be free of charge.

To join us, please register on this link: http://eepurl.com/gDLYUD and we will send you the Webinar details.

Speaker’s Short Biography

Diethelm Johannsmann is Professor of Physical Chemistry and the director of the Physical Chemistry Institute at Clausthal University of Technology, Germany. He has made fundamental contributions to the subject of QCM(D), reflected in more than 150 articles, several book chapters, and books. His model is widely used in the analysis of QCM-D data, and he developed free software for QCM-D data analysis and modelling.  You can find more information about his work on his website, https://www.pc.tu-clausthal.de/en/research/johannsmann-group/prof-dr-diethelm-johannsmann/.

 

QCMD Immunosensor

New QCMD Immunosensor Application Note

/in , /by

May 20th 2021: AWSensors is pleased to invite you to take a look to its new Immunosensor Application Note entitled “QCMD immunosensor for small molecule analytes“.

Summary of the Note

A QCMD-based immunoassay for label-free analysis of small molecule concentration in industrial samples was developed using an AWS QCMD system with surface-modified 5 MHz fundamental frequency QCMD sensors. Accuracy and precision of the immunoassay is evaluated with respect to the industry-standard HPLC reference.

QCMD Immunosensor

Introduction

Accurate, rapid, and cost-effective quantification of small molecule analytes is a pressing problem in various industrial (food, agriculture, environmental protection) and health-related fields. Existing approaches include enzyme-linked immunosorbent assays (ELISAs) and various types of chromatography (e.g., High Performance Liquid Chromatography, HPLC). These approaches require trained personal and centralized laboratories, and their deployment in the field is difficult or impossible.

Quartz Crystal Microbalance with Dissipation, or QCMD, is emerging as a promising technology for the development of fast, portable, automated, and cost-effective immunosensors. Here, we demonstrate a competitive small molecule immunoassay based on the AWSensors QCMD technology.

Download Full Application Note

You can download the full Application Note in pdf file from this link or download it from our Applications Web Page where you can find this and the rest of our Application Notes.

Other references

Antibodies

Antibody Detection with Quartz Crystal Microbalance

/in , /by

May 10th 2021: AWSensors offers acoustic sensors for antibody detection. Acoustic biosensor-based immunosensing with  High-Fundamental Frequency Quartz Crystal Microbalance (HFF-QCM) and Love-SAW sensors offers several advantages over Enzyme Linked Immuno Assay (ELISA) or Surface Plasmon Resonance (SPR).

Acoustic sensors antibody detection advantages over ELISA

  • Sensitivity approximately as a standard ELISA or better.
  • Acoustic sensors offer label-free detection of the antibody-antigen binding.
  • Full automation.
  • Pre-calibrated (the user does not need to run the standards. More samples can be run. Reduced cost per sample).
  • Speed.
  • Quantitative real-time /in-situ monitoring.
  • Turn-key solution (no need to specialized detection equipment, reader, or spectrophotometer).
  • Reduced complexity, relaxed requirements for trained personnel.
  • Small volumes (~ 10 of ul per sample).
  • Parallelization and multiple analyte detection through sensor arrays.
  • Sensor re-usablity, leading to reduced assay cost.

Acoustic sensors antibody detection advantages over SPR

  • Better sensitivity.
  • QCM also sees solvent.
  • Provides conformational information of the surface film.
  • Miniaturization and integration into portable systems.
  • Easier to develop parallel and multiple analyte assays through sensor arrays.
  • Affordability.

Therefore, one can develop biosensors based on acoustic immunosensors with highly attractive features in order to rapidly detect pathogens like viruses and bacteria [1], and low molecular weigh compounds.

Application Example

Our Biosensor Application Note  is an application example where we describe a sensitive detection of a low molecular weight pesticide carbaryl using competitive immunoassay with hapen-conjugates immobilized on high-fundamental frequency QCMD sensors, SAMs and monoclonal antibodies (MAb) [2, 3]. As a result, we achieved a very sensitive detection of the carbaryl analyte.

Biosensor

 

References

[1] Surface Generated Acoustic Wave Biosensors for the Detection of Pathogens: A Review 

[2] High-frequency phase shift measurement greatly enhances the sensitivity of QCM immunosensors

[3] Love Wave Immunosensor for the Detection of Carbaryl Pesticide  

Carbaryl Biosensor based on antibody detection

Biosensor Application Note

/in , /by

July 3rd 2020: AWSensors is pleased to invite you to take a look to the Biosensor Application Note entitled “Acoustic Biosensor“.

Summary of the Note

An immunosensor application for determination of carbaryl pesticide was developed by using AWS A20 research platform and AWS F20 Fluidic System. Carbaryl was chosen as the model analyte. Two kinds of acoustic sensors were employed: AWS HFF-QCM sensors (50 MHz and 100 MHz) and Love-SAW sensors with appropriate cells. The AWS A20 platform allowed monitoring phase-shift changes at constant frequency as a function of the sensor surface mass changes.

Biosensor

Introduction

Sensor functionalization: Carbaryl hapten conjugate was covalently immobilized by means of Self Assembled Monolayer (SAM).

Immunoassay format: The chosen competitive immunoassay was a binding-inhibition test based on conjugate-coated format. Carbaryl analyte competes against the immobilized hapten-conjugate for Monoclonal Antibodies.

Carbaryl detection: Samples were injected onto the sensors’ surfaces. AWS software allowed controlling sample injection and fluidics. Furthermore, the employed platform allowed performing the measurements at a constant temperature of 25°C ± 0.05°C.

Since analyte inhibits antibody binding to its respective immobilized conjugates, increasing concentrations of analyte are detected by a change in the increment of the phase-shift of the sensor. The following figures present a representative assay cycle selected from a continuous monitoring in a carbaryl determination, for 100 MHz HFF QCM and 120MHz Love Wave Sensors.

Continue reading by downloading the full Application Note (below) …

Download Full Application Note

You can download the full Application Note in pdf file from this link or download it from our Applications Web Page where you can find this and the rest of our Application and Technology Notes.

A High Fundamental Frequency QCM Immunosensor for Tuberculosis Detection

/in , /by

AWSensors biosensor for tuberculosis detection

Authors: Ángel Montoya, Carmen March, Yeison J. Montagut, Maria J. Moreno, Juan J. Manclus, Antonio Arnau, Yolanda Jiménez, Marisol Jaramillo, Paula A. Marin, Robinson A. Torres

Journal:  Current topics in Medicinal Chemistry (2017)

Background: Tuberculosis, one of the oldest diseases affecting human beings, is still considered as a world public health problem by the World Health Organization.

Method & Material: Therefore, there is a need for new and more powerful analytical methods for early illness diagnosis. With this idea in mind, the development of a High Fundamental Frequency (HFF) piezoelectric immunosensor for the sensitive detection of tuberculosis was undertaken. A 38 kDa protein secreted by Mycobacterium tuberculosis was first selected as the target biomarker. Then, specific monoclonal antibodies (MAbs) were obtained. Myc-31 MAb, which showed the highest affinity to the analyte, was employed to set up a reference enzyme-linked immunosorbent assay (ELISA) with a limit of detection of 14 ng mL-1 of 38 kDa antigen.

Results & Discussion: For the development of the HFF piezoelectric immunosensor, 100 MHz AWSensors quartz crystals were used as transducer elements. The gold electrode surface was functionalized by covalent immobilization of the target biomarker through mixed self-assembled monolayers (mSAM) of carboxylic alkane thiols. A competitive immunoassay based on Myc-31 MAb was integrated with the transducer as sensing bio-recognition event. Reliable assay signals were obtained using low concentrations of antigen for functionalization and MAb for the competitive immunoassay. Under optimized conditions, the HFF immunosensor calibration curve for 38 kDa determination showed a limit of detection as low as 11 ng mL-1 of the biomarker. The high detectability attained by this immunosensor, in the picomolar range, makes it a promising tool for the easy, direct and sensitive detection of the tuberculosis biomarker in biological fluids such as sputum.

You may review the full paper here