biotechnet Switzerland.

The COVID-19 pandemic has raised in 2020 an unprecedented need for diagnostic testing, especially rapid testing, for SARS-CoV-2 infections. POC diagnostic tools, however, have clearly also importance in other domains such as oncology and women's health, because of the efficiency and convenience factors playing an increasingly important role in a mobile (and sometimes confined) and digitally connected world. Out of necessity, the 3rd edition of the Swiss Symposium in POC Diagnostics, originally planned to take place at the La Poste Conference Center in Visp, was smoothly run online with 170 engaged participants from science, industry and laboratory medicine.

4th Swiss Symposium in Point-of-Care Diagnostics held at the Davos Conference Center on 21 October, 2021.

After last year's successful online symposium, the 4th edition of the Swiss Symposium in POC Diagnostics gathered more than 150 participants from medicine, industry and science as well as from different European countries to meet at the Davos Conference Center for an exciting program with 13 expert speakers, a poster session and a product & technology exhibition. The mandatory COVID-certificate to access the event has allowed people to meet (again at last!), network and share their views and success stories in the field of POC Diagnostics that continues to be propelled by digitalization, new technological possibilities, user needs and the COVID-19 pandemic.

Analytical Platforms at Swiss Universities of Applied Sciences.

Numerous projects and industrial and academic collaborations benefit from state-of-the-art facilities and expertise in analytical chemistry available at the Swiss Universities of Applied Sciences. This review summarizes areas of expertise in analytical sciences at the University of Applied Sciences and Arts Northwestern Switzerland (FHNW), the University of Applied Sciences and Arts Western Switzerland (HES-SO), and the Zurich University of Applied Sciences (ZHAW). We briefly discuss selected projects in different fields of analytical sciences.

Report of the 2nd Swiss Symposium in Point-of-Care Diagnostics Chur, October 18, 2018.

After a successful first launch of the Swiss Symposium in Point-of-Care Diagnostics at the HES-SO Valais-Wallis in 2017 (CHIMIA 2018, 72, 80), the organization of the 2nd edition of this Symposium was spearheaded by the CSEM team in Landquart . Again close to 200 participants from sci- ence, industry and laboratory medicine attended this event during a beautiful and warm autumn day at the awesome Auditorium of the Graubündner Kantonalbank (GKB) in Chur.

Quo Vadis Point-of-Care Diagnostics? Report II of the SWISS SYMPOSIUM in Point-of-Care Diagnostics 2017.

U.S. studies show that the global point-of-care (POC) diagnostics market will reach $40.5 bn by 2022, with a compound annual growth rate (CAGR) of 10%. This is one of the reasons why HES-SO Valais-Wallis and CSEM, acting on behalf of the NTN Swiss Biotech thematic platform in vitro Diagnostics (TP IVD), invited interested parties on October 26, 2017 to the SWISS SYMPOSIUM in Point-of-Care Diagnostics (see CHIMIA No. 12/2017). We now bring the second report on the future prospects of POC diagnostics.

Surface chemistry at Swiss Universities of Applied Sciences.

In the Swiss Universities of Applied Sciences, a number of research groups are involved in surface science, with different methodological approaches and a broad range of sophisticated characterization techniques. A snapshot of the current research going on in different groups from the University of Applied Sciences and Arts Western Switzerland (HES-SO), the Zurich University of Applied Sciences (ZHAW) and the University of Applied Sciences and Arts Northwestern Switzerland (FHNW) is given.

Strategies in mass spectrometry for the assignment of Cys-Cys disulfide connectivities in proteins.

Elucidating disulfide linkage patterns is a crucial part of protein characterization, for which mass spectrometry (MS) is now an indispensable analytical tool. In many cases, MS-based disulfide connectivity assignment is straightforwardly achieved using one-step protein fragmentation in the unreduced form followed by mass measurement of bridged fragments. By contrast, venom proteins, which are receiving increasing interest as potential therapeutics, are a challenge for MS-based disulfide assignment due to their numerous closely spaced cysteines and knotted disulfide structure, requiring creative strategies to determine their connectivity. Today, these include the use of an array of reagents for enzymatic and/or chemical cleavage, partial reduction, differential cysteine labeling and tandem MS. This review aims to describe the toolkit of techniques available to MS users approaching both straightforward and complex disulfide bridge assignments, with a particular focus on strategies utilizing standard instrumentation found in a well-equipped analytical or proteomics laboratory.

ADIBO-based "click" chemistry for diagnostic peptide micro-array fabrication: physicochemical and assay characteristics.

Several azide-derivatized and fluorescently-labeled peptides were immobilized on azadibenzocyclooctyne (ADIBO)-activated slide surfaces via a strain-promoted alkyne-azide cycloaddition (SPAAC) reaction revealing excellent immobilization kinetics, good spot homogeneities and reproducible fluorescence signal intensities. A myc-peptide micro-array immunoassay showed an antibody limit-of-detection (LOD) superior to a microtiter plate-based ELISA. Bovine serum albumin (BSA) and dextran covalently attached via "click" chemistry more efficiently reduced non-specific binding (NSB) of fluorescently-labeled IgG to the microarray surface in comparison to immobilized hexanoic acid and various types of polyethylene glycol (PEG) derivatives. Confirmation of these findings via further studies with other proteins and serum components could open up new possibilities for human sample and microarray platform-based molecular diagnostic tests.

Manufacturing of Peptide Microarrays Based on Catalyst-Free Click Chemistry.

Immobilization of peptides to a solid surface is frequently an important first step before they can be probed with a variety of biological samples in a heterogeneous assay format for research and clinical diagnostic purposes. Peptides can be derivatized in many ways to subsequently covalently attach them to an activated solid surface such as, for instance, epoxy-functionalized glass slides. Here, we describe a clean, efficient, and reproducible fabrication process based on catalyst-free click chemistry compatible with the construction of low- to high-density peptide microarrays.

A novel point-of-care diagnostic prototype system for the simultaneous electrochemiluminescent sensing of multiple traumatic brain injury biomarkers.

Traumatic brain injuries (TBI) are typically acquired when a sudden violent event causes damage to the brain tissue. A high percentage (70-85%) of all TBI patients are suffering from mild TBI (mTBI), which is often difficult to detect and diagnose with standard imaging tools (MRI, CT scan) due to the absence of significant lesions and specific symptoms. Recent studies suggest that a screening test based on the measurement of a protein biomarker panel directly from a patient's blood can facilitate mTBI diagnosis. Herein, we report a novel prototype system designed as a precursor of a future hand-held point-of-care (POC) diagnostic device for the simultaneous multi-biomarker sensing, employing a microarray-type spatially resolved electrochemiluminescence immunoassay (SR-ECLIA). The small tabletop prototype consists of a screen-printed electrode compartment to conduct multi-analyte ECL sandwich assays, a potentiostat module and a light collection module, all integrated into a compact 3D-printed housing (18.2 × 16.5 × 5.0 cm), as well as an sCMOS detector. Based on this design concept, further miniaturization, system integration, performance optimization and clinical evaluation shall pave the way towards the development of a portable instrument for use at the site of accident and healthcare. To demonstrate the system's feasibility, current performance and efficiency, the simultaneous detection of three mTBI biomarkers (GFAP, h-FABP, S100ß) in 50% serum was achieved in the upper pg mL-1 range. The proposed device is amenable to the detection of other biomarker panels and thus could open new medical diagnostic avenues for sensitive multi-analyte measurements with low-volume biological sample requirements.

Opening the black box of traumatic brain injury: a holistic approach combining human 3D neural tissue and an in vitro traumatic brain injury induction device.

Traumatic brain injury (TBI) is caused by a wide range of physical events and can induce an even larger spectrum of short- to long-term pathophysiologies. Neuroscientists have relied on animal models to understand the relationship between mechanical damages and functional alterations of neural cells. These in vivo and animal-based in vitro models represent important approaches to mimic traumas on whole brains or organized brain structures but are not fully representative of pathologies occurring after traumas on human brain parenchyma. To overcome these limitations and to establish a more accurate and comprehensive model of human TBI, we engineered an in vitro platform to induce injuries via the controlled projection of a small drop of liquid onto a 3D neural tissue engineered from human iPS cells. With this platform, biological mechanisms involved in neural cellular injury are recorded through electrophysiology measurements, quantification of biomarkers released, and two imaging methods [confocal laser scanning microscope (CLSM) and optical projection tomography (OPT)]. The results showed drastic changes in tissue electrophysiological activities and significant releases of glial and neuronal biomarkers. Tissue imaging allowed us to reconstruct the injured area spatially in 3D after staining it with specific nuclear dyes and to determine TBI resulting in cell death. In future experiments, we seek to monitor the effects of TBI-induced injuries over a prolonged time and at a higher temporal resolution to better understand the subtleties of the biomarker release kinetics and the cell recovery phases.

Construction of a peptide microarray for auto-anti- body detection.

Peptide and protein microarrays provide a multiplex approach to identification and quantification of protein-protein interactions (PPI), useful to study for instance antigen-antibody properties. Multivariate serology assays detecting multiple tumor auto-antibodies (TAA) is an emerging class of blood tests for cancer detection. Here we describe the efficient coupling of peptide baits derived from the BRCA1-associated RING domain protein 1 (BARD1) to a solid surface and detection of a commercially available anti-BARD1 antibody with this newly designed peptide microarray. Analytical sensitivity and specificity were shown to be comparable to a microtiter plate based enzyme-linked immunosorbent assay (ELISA).

Fluorescence-polarization immunoassays within glass fiber micro-chambers enable tobramycin quantification in whole blood for therapeutic drug monitoring at the point of care.

Many therapeutic drugs require monitoring of their concentration in blood followed by dose adjustments in order to ensure efficacy while minimizing adverse effects. It would be highly desirable to perform such measurements rapidly and with reduced sample volumes to support point-of-care testing. Here, we demonstrate that the concentration of small therapeutics can be determined in whole blood within paper-like membranes using Fluorescence Polarization Immunoassay (FPIA). Different types of paper-like materials such as glass microfibers, cellulose and filter paper were investigated for artefacts such as scattering or autofluorescence. Accurate determination of the fluorescence polarization of red-emitting fluorophores at sub-nanomolar concentrations was feasible within glass fiber membranes. This enabled the development of a competitive immunoassay for the quantification of the antibiotic tobramycin using only 1 µL of plasma in glass fiber micro-chambers. Furthermore, the same membrane was used for transversal separation of blood cells followed by accurate FPIA read-out at the bottom part of the micro-chamber. For quantification of tobramycin, 1 µL of whole blood was incubated with the immunoassay reagents during only 3 min before deposition in the micro-chamber and analysis. Within the therapeutic window, coefficients of variation were around 20% and recoveries between 80 and 105%. Owing to the simplified procedure requiring no centrifugation, the reduced blood sample volume and the rapid analysis time, we envision that this novel method supports the performance of therapeutic drug monitoring directly at the point of care.

Electrochemical sensing of blood proteins for mild traumatic brain injury (mTBI) diagnostics and prognostics: towards a point-of-care application.

Traumatic Brain Injury (TBI) being one of the principal causes of death and acquired disability in the world imposes a large burden on the global economy. Mild TBI (mTBI) is particularly challenging to assess due to the frequent lack of well-pronounced post-injury symptoms. However, if left untreated mTBI (especially when repetitive) can lead to serious long-term implications such as cognitive and neuropathological disorders. Computer tomography and magnetic resonance imaging commonly used for TBI diagnostics require well-trained personnel, are costly, difficult to adapt for on-site measurements and are not always reliable in identifying small brain lesions. Thus, there is an increasing demand for sensitive point-of-care (POC) testing tools in order to aid mTBI diagnostics and prediction of long-term effects. Biomarker quantification in body fluids is a promising basis for POC measurements, even though establishing a clinically relevant mTBI biomarker panel remains a challenge. Actually, a minimally invasive, rapid and reliable multianalyte detection device would allow the efficient determination of injury biomarker release kinetics and thus support the preclinical evaluation and clinical validation of a proposed biomarker panel for future decentralized in vitro diagnostics. In this respect electrochemical biosensors have recently attracted great attention and the present article provides a critical study on the electrochemical protocols suggested in the literature for detection of mTBI-relevant protein biomarkers. The authors give an overview of the analytical approaches for transduction element functionalization, review recent technological advances and highlight the key challenges remaining in view of an eventual integration of the proposed concepts into POC diagnostic solutions.

Point-of-Care Therapeutic Drug Monitoring for Precision Dosing of Immunosuppressive Drugs.

BACKGROUND: Immunosuppressive drugs (ISD) are an essential tool in the treatment of transplant rejection and immune-mediated diseases. Therapeutic drug monitoring (TDM) for determination of ISD concentrations in biological samples is an important instrument for dose personalization for improving efficacy while reducing side effects. While currently ISD concentration measurements are performed at specialized, centralized facilities, making the process complex and laborious for the patient, various innovative technical solutions have recently been proposed for bringing TDM to the point-of-care (POC). CONTENT: In this review, we evaluate current ISD-TDM and its value, limitations, and proposed implementations. Then, we discuss the potential of POC-TDM in the era of personalized medicine, and provide an updated review on the unmet needs and available technological solutions for the development of POC-TDM devices for ISD monitoring. Finally, we provide concrete suggestions for the generation of a meaningful and more patient-centric process for ISD monitoring. SUMMARY: POC-based ISD monitoring may improve clinical care by reducing turnaround time, by enabling more frequent measurements in order to obtain meaningful pharmacokinetic data (i.e., area under the curve) faster reaction in case of problems and by increasing patient convenience and compliance. The analysis of the ISD-TDM field prompts the evolution of POC testing toward the development of fully integrated platforms able to support clinical decision-making. We identify 4 major areas requiring careful combined implementation: patient usability, data meaningfulness, clinicians' acceptance, and cost-effectiveness.

Manufacturing of Peptide Microarrays Based on Catalyst-Free Click Chemistry.

Immobilization of peptides to a solid surface is frequently an important first step before they can be probed with a variety of biological samples in a heterogeneous assay format for research and clinical diagnostic purposes. Peptides can be derivatized in many ways to subsequently covalently attach them to an activated solid surface such as epoxy-functionalized glass slides. Here, we describe a clean, efficient, and reproducible fabrication process based on catalyst-free click chemistry compatible with the construction of low- to high-density peptide microarrays.