Tag Archive for: biosensors

Scientific publication

Real-time monitoring of dephosphorylation process of phosphopeptide and rapid assay of PTP1B activity based on a 100 MHz QCM biosensing platform

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Authors: Shuping Liu, Qingqing Zhang, Xiaohua Zhang, Cuicui Du, Jinhua Chen, Shihui Si

Journal: Talanta

Abstract

The misregulation of protein phosphatases is a key factor in the development of many human diseases, notably cancers. Here, based on a 100 MHz quartz crystal microbalance (QCM) biosensing platform, the dephosphorylation process of phosphopeptide (P-peptide) caused by protein tyrosine phosphatase 1B (PTP1B) was monitored in real time for the first time and PTP1B activity was assayed rapidly and sensitively. The QCM chip, coated with a gold (Au) film, was used to immobilized thiol-labeled single-stranded 5′-phosphate-DNAs (P-DNA) through Au–S bond. The P-peptide, specific to PTP1B, was then connected to the P-DNA via chelation between Zr4+ and phosphate groups. When PTP1B was injected into the QCM flow cell where the P-peptide/Zr4+/MCH/P-DNA/Au chip was placed, the P-peptide was dephosphorylated and released from the Au chip surface, resulting in an increase in the frequency of the QCM Au chip. This allowed the real-time monitoring of the P-peptide dephosphorylation process and sensitive detection of PTP1B activity within 6 min with a linear detection range of 0.01–100 pM and a detection limit of 0.008 pM. In addition, the maximum inhibitory ratios of inhibitors were evaluated using this proposed 100 MHz QCM biosensor. The developed 100 MHz QCM biosensing platform shows immense potential for early diagnosis of diseases related to protein phosphatases and the development of drugs targeting protein phosphatases.

You may read the full paper here.

Publication on AWSensors technology

Acoustic detection of a mutation-specific Ligase Chain Reaction based on liposome amplification

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Authors: Nikoletta Naoumi, Monica Araya-Farias, Maria Megariti, Lucile Alexandre, George Papadakis, Stephanie Descroix, and Electra Gizeli

Journal: Analyst

Abstract

Single nucleotide variants (SNVs) play a crucial role in understanding genetic diseases, cancer development, and personalized medicine. However, existing ligase-based amplification and detection techniques, such as Rolling Circle Amplification and Ligase Detection Reaction, suffer from low efficiency and difficulties in product detection. To address these limitations, we propose a novel approach that combines Ligase Chain Reaction (LCR) with acoustic detection using highly dissipative liposomes. In our study, we are using LCR combined with biotin- and cholesterol-tagged primers to produce amplicons also modified at each end with a biotin and cholesterol molecule. We then apply the LCR mix without any purification directly on a neutravidin modified QCM device Au-surface, where the produced amplicons can bind specifically through the biotin end. To improve sensitivity, we finally introduce liposomes as signal enhancers. For demonstration, we used the detection of the BRAF V600E point mutation versus the wild-type allele, achieving an impressive detection limit of 220 aM of the mutant target in the presence of the same amount of the wild type. Finally, we combined the assay with a microfluidic fluidized bed DNA extraction technology, offering the potential for semi-automated detection of SNVs in patients’ crude samples. Overall, our LCR/acoustic method outperforms other LCR-based approaches and surface ligation biosensing techniques in terms of detection efficiency and time. It effectively overcomes challenges related to DNA detection, making it applicable in diverse fields, including genetic disease and pathogen detection.

You may read the full paper here.

Publication on AWSensors technology

Acoustic Array Biochip Combined with Allele-Specific PCR for Multiple Cancer Mutation Analysis in Tissue and Liquid Biopsy

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Authors: Nikoletta Naoumi, Kleita Michaelidou, George Papadakis, Agapi E. Simaiaki, Román Fernández, Maria Calero, Antonio Arnau, Achilleas Tsortos, Sofia Agelaki, and Electra Gizeli

Journal: ACS Sens. (2022)

Abstract

Regular screening of point mutations is of importance to cancer management and treatment selection. Although techniques like next-generation sequencing and digital polymerase chain reaction (PCR) are available, these are lacking in speed, simplicity, and cost-effectiveness. The development of alternative methods that can detect the extremely low concentrations of the target mutation in a fast and cost-effective way presents an analytical and technological challenge. Here, an approach is presented where for the first time an allele-specific PCR (AS-PCR) is combined with a newly developed high fundamental frequency quartz crystal microbalance array as biosensor for the amplification and detection, respectively, of cancer point mutations. Increased sensitivity, compared to fluorescence detection of the AS-PCR amplicons, is achieved through energy dissipation measurement of acoustically “lossy” liposomes binding to surface-anchored dsDNA targets. The method, applied to the screening of BRAF V600E and KRAS G12D mutations in spiked-in samples, was shown to be able to detect 1 mutant copy of genomic DNA in an excess of 104 wild-type molecules, that is, with a mutant allele frequency (MAF) of 0.01%. Moreover, validation of tissue and plasma samples obtained from melanoma, colorectal, and lung cancer patients showed excellent agreement with Sanger sequencing and ddPCR; remarkably, the efficiency of this AS-PCR/acoustic methodology to detect mutations in real samples was demonstrated to be below 1% MAF. The combined high sensitivity and technology-readiness level of the methodology, together with the ability for multiple sample analysis (24 array biochip), cost-effectiveness, and compatibility with routine workflow, make this approach a promising tool for implementation in clinical oncology labs for tissue and liquid biopsy.

 

You may read the full paper here.

Scientific publication

High Frequency (100, 150 MHz) Quartz Crystal Microbalance (QCM) Piezoelectric Genosensor for the Determination of the Escherichia coli O157 rfbE Gene

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Authors: Kaory Barrientos, María Isabel Rocha, Marisol Jaramillo and Neil Aldrín Vásquez.
Journal: Analytical Letters (2022)

 

Abstract

Escherichia coli O157 (E. coli O157) is responsible for outbreaks of high morbidity in food-borne infections. The development of sensitive, reliable, and selective detection systems is of great importance in food safety. In this work, two high fundamental frequency (HFF) piezoelectric genosensors (100 and 150 MHz) were designed and validated for the rfbE gene detection, which encodes O-antigen in E. coli O157. HFF resonators offer improved sensitivity, small sample volumes, and the possibility of integration into lab-on-a-chip devices, but their sensing capabilities have not yet been fully explored. This HFF-QCM genosensor uses the method of physisorption based on the union between the streptavidin and the biotin to immobilize the genetic bioreceptor on the surface and detect its hybridization with the target sequence. Parameters such as molecular coating, specificity, and variability were tested to enhance its performance. Although both genosensors evaluated are able to determine the target, the 100 MHz device has a higher response to the analyte than the 150 MHz platform. This is the first step in the development of an HFF-QCM genosensor that may be used as a trial test of E. coli O157 in large batches of samples.

 

You may read the full paper here.

The difference the “D” makes in QCMD

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AWSensors presents a new Technology Note on the importance of dissipation measuring when working with QCMD: “The difference the “D” makes in QCMD”.

Dissipation

What is dissipation, and why it is useful?

Quartz Crystal Microbalance with Dissipation, or QCMD, is having a tremendous impact on research in the soft and biological interfaces fields because of its versatility and the wealth of information it provides. In this Technology Note, we discuss the origins of dissipation in the different systems studied by QCMD, from complex fluids and polymer films to biomolecular and particle assemblies, and the information dissipation can provide, from characterizing viscoelasticity to studying molecular conformation.

In this Technical Note we discuss the origins of dissipation, how it can be used to verify the applicability of the Sauerbrey relationship and their interaction with the viscoelasticity and in the biological sensing.

 

Download the Full Technology Note

You can read and download the full Technology Note in pdf file from this link. A list of our Technology Notes can be found on our Technology Web Page..

 

 

manufacturing

AWSensors cooperation with UPVfab

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AWSensors, one of the first spin-off companies to emerge from the Polytechnic University of Valencia (UPV), sees a space for cooperation with UPVfab. Located at the Polytechnic City of Innovation (UPV’s Science Park), UPVfab is a breakthrough project, counting with a ~500 m2 clean room space and equipped with high-tech instruments, with applications in the areas of research in Photonics, Electronics and Chemistry.

In this initiative participate five research institutes located at the UPV: the Institute of Telecommunications and Multimedia Applications (iTEAM), the Instituto de Tecnología Quimica (ITQ-CSIC), the Instituto de Instrumentación para Imagen Molecular (I3M, UPV-CSIC), el Center for Research and Innovation in Bioengineering, and the Interuniversity Research Institute for Molecular Recognition and Technological Development (IDM) (IDM, UPV-UV).

However, this new project not only seeks to support academic research, but to strengthen its cooperation with industry partners as well. Prof. Antonio Arnau, full professor at UPV’s Department of Electronic Engineering and founder of AWSensors, acknowledges the importance of having these kind of installations that would make possible to validate new developments based on AWSensors’ proprietary array Quartz Crystal Microbalance with Dissipation (QCMD) biosensor technology. The company is already testing this technology in Healthcare applications, as an instrument for precision medicine through fast and simple diagnosis of cancer mutations for a personalized treatment and monitoring of its evolution.

AWSensors is always interested in productive public and private partnerships that help us further the developments in QCMD devices, sensors, and applications of interest.

 

Source: https://valenciaplaza.com/upv-crea-sala-limpia-investigar-fotonica-electronica-quimica

QCMD webinar

QCM-D Webinar

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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

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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

X4 QCMD System

X4 Launching

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January 19th 2021: X4 launching

AWSensors is pleased to announce the launching of its new Advanced Multichannel QCMD system, the X4 Instrument, which allows the users to boost their productivity.

X4 Instrument

Visit X4 launching Landing-page

Learn more about this new instrument in its landing page.

QCMD in Lipid Research

QCMD in Lipid Research Tech Note

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October 15th 2020: AWSensors is pleased to invite you to take a look to its Technology Note entitled “QCMD in Lipid Research”.

Summary of the Note

QCMD is a label-free surface-analytical technique based on a quartz resonator excited to oscillate at its resonance frequency on one or more overtones. Resonators can have various coatings: gold (Au), silica (SiO2), titania (TiO2), etc. It works in aqueous media or organic solvents and is therefore widely used for studying solid/liquid interfaces. At each overtone, QCMD measures changes in the resonance frequency and energy dissipation due to the processes occurring at the resonator surface. Examples of such processes include formation of a film or changes in the geometrical or physical properties of the film.

The key feature that makes QCMD useful in lipid research is its ability to distinguish between different geometries and topologies of lipidic assemblies at interfaces, for example, homogenous solid-supported bilayers or monolayers vs. adsorbed liposomes or other structures (such as cubosomes) without relying on fluorescent or deuterated labels but by relying on the combination of the frequency and dissipation.

QCMD in Lipid Research

Introduction

Lipid-related QCMD work can be grouped into several topics, with a total of more than a thousand publications:
• Studies focusing on the interactions between lipids and surfaces.
• Studies focusing on the properties of the lipids, such as their phase behavior, adsorbed liposome deformation, etc.
• Studies examining interactions between lipids and membrane-binding proteins, peptides or viruses. Particularly interesting is that QCMD offers a way to study clustering of membrane-bound proteins.
• Studies focusing on the interactions of lipids with polymers or with nanoparticles.

 

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

Download the Full Technology Note

You can download the full Note in pdf format through this link. A list of our Technology Notes can be found on our Technology Web Page.