scholarly journals Optimization of an ammonia assay based on transmembrane pH-gradient polymersomes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anastasia Spyrogianni ◽  
Charlotte Gourmel ◽  
Leopold Hofmann ◽  
Jessica Marbach ◽  
Jean-Christophe Leroux
Keyword(s):  
Near Infrared ◽  
Biological Fluids ◽  
Point Of Care ◽  
Ammonia Concentration ◽  
Ph Gradient ◽  
Fluorescence Signal ◽  
Bioanalytical Method Validation ◽  
Regulatory Guidelines ◽  
High Bilirubin ◽  
Assay Interference

AbstractReliable ammonia quantification assays are essential for monitoring ammonemia in patients with liver diseases. In this study, we describe the development process of a microplate-based assay for accurate, precise, and robust ammonia quantification in biological fluids, following regulatory guidelines on bioanalytical method validation. The assay is based on transmembrane pH-gradient polymersomes that encapsulate a pH-sensitive ratiometric fluorophore, the fluorescence signal of which correlates with the ammonia concentration in the sample. Using a four-parameter logistic regression, the assay had a large quantification range (30–800 μM ammonia). As for selectivity, the presence of amino acids or pyruvate (up to clinically relevant concentrations) showed no assay interference. In samples with low bilirubin levels, polymersomes containing the fluorophore pyranine provided accurate ammonia quantification. In samples with high bilirubin concentrations, billirubin’s optical interference was alleviated when replacing pyranine with a close to near-infrared hemicyanine fluorophore. Finally, the assay could correctly retrieve the ammonia concentration in ammonia-spiked human plasma samples, which was confirmed by comparing our measurements with the data obtained using a commercially available point-of-care device for ammonia.

scholarly journals Optimization of an Ammonia Assay based on Transmembrane pH-gradient Polymersomes

2021 ◽  
Author(s):  
Anastasia Spyrogianni ◽  
Charlotte Gourmel ◽  
Leopold Hofmann ◽  
Jessica Marbach ◽  
Jean-Christophe Leroux
Keyword(s):  
Near Infrared ◽  
Biological Fluids ◽  
Point Of Care ◽  
Ammonia Concentration ◽  
Ph Gradient ◽  
Fluorescence Signal ◽  
Bioanalytical Method Validation ◽  
Regulatory Guidelines ◽  
High Bilirubin ◽  
Assay Interference

Abstract Reliable ammonia quantification assays are essential for monitoring ammonemia in patients with liver diseases. In this study, we describe the development process of a microplate-based assay for accurate, precise, and robust ammonia quantification in biological fluids, following regulatory guidelines on bioanalytical method validation. The assay is based on transmembrane pH-gradient polymersomes that encapsulate a pH-sensitive ratiometric fluorophore, the fluorescence signal of which correlates with the ammonia concentration in the sample. Using four-parameter logistic regression, the assay had a large quantification range (30–800 µM ammonia). As for selectivity, the presence of amino acids or pyruvate (up to clinically relevant concentrations) showed no assay interference. In samples with low bilirubin levels, polymersomes containing the fluorophore pyranine provided accurate ammonia quantification. In samples with high bilirubin concentrations, billirubin’s optical interference was alleviated when replacing pyranine with a close to near-infrared hemicyanine fluorophore. Finally, the assay could correctly retrieve the ammonia concentration in ammonia-spiked human plasma samples, which was confirmed by comparing our measurements with the data obtained using a commercially available point-of-care device for ammonia.

scholarly journals Methylglyoxal Adducts Levels in Blood Measured on Dried Spot by Portable Near-Infrared Spectroscopy

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2432
Author(s):  
Giuseppe Bonapace ◽  
Francesco Gentile ◽  
Nicola Coppedé ◽  
Maria Laura Coluccio ◽  
Virginia Garo ◽  
...  
Keyword(s):  
Near Infrared ◽  
Biological Fluids ◽  
Point Of Care ◽  
Electronic Devices ◽  
Sample Pretreatment ◽  
Final Model ◽  
Vibration Absorption ◽  
Altered Glucose ◽  
Learning Machine ◽  
Different Levels

The altered glucose metabolism characterising cancer cells determines an increased amount of methylglyoxal in their secretome. Previous studies have demonstrated that the methylglyoxal, in turn, modifies the protonation state (PS) of soluble proteins contained in the secretomes of cultivated circulating tumour cells (CTCs). In this study, we describe a method to assess the content of methylglyoxal adducts (MAs) in the secretome by near-infrared (NIR) portable handheld spectroscopy and the extreme learning machine (ELM) algorithm. By measuring the vibration absorption functional groups containing hydrogen, such as C-H, O-H and N-H, NIR generates specific spectra. These spectra reflect alterations of the energy frequency of a sample bringing information about its MAs concentration levels. The algorithm deciphers the information encoded in the spectra and yields a quantitative estimate of the concentration of MAs in the sample. This procedure was used for the comparative analysis of different biological fluids extracted from patients suspected of having cancer (secretome, plasma, serum, interstitial fluid and whole blood) measured directly on the solute left on a surface upon a sample-drop cast and evaporation, without any sample pretreatment. Qualitative and quantitative regression models were built and tested to characterise the different levels of MAs by ELM. The final model we selected was able to automatically segregate tumour from non-tumour patients. The method is simple, rapid and repeatable; moreover, it can be integrated in portable electronic devices for point-of-care and remote testing of patients.

scholarly journals A Paper-Based Near-Infrared Optical Biosensor for Quantitative Detection of Protease Activity Using Peptide-Encapsulated SWCNTs

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5247 ◽  
Author(s):  
Vlad Shumeiko ◽  
Yossi Paltiel ◽  
Gili Bisker ◽  
Zvi Hayouka ◽  
Oded Shoseyov
Keyword(s):  
Protease Activity ◽  
Near Infrared ◽  
Biological Fluids ◽  
Point Of Care ◽  
Optical Biosensor ◽  
Infrared Region ◽  
Enzymatic Digestion ◽  
Single Wall Carbon Nanotubes ◽  
Quantitative Detection ◽  
Significant Drop

A protease is an enzyme that catalyzes proteolysis of proteins into smaller polypeptides or single amino acids. As crucial elements in many biological processes, proteases have been shown to be informative biomarkers for several pathological conditions in humans, animals, and plants. Therefore, fast, reliable, and cost-effective protease biosensors suitable for point-of-care (POC) sensing may aid in diagnostics, treatment, and drug discovery for various diseases. This work presents an affordable and simple paper-based dipstick biosensor that utilizes peptide-encapsulated single-wall carbon nanotubes (SWCNTs) for protease detection. Upon enzymatic digestion of the peptide, a significant drop in the photoluminescence (PL) of the SWCNTs was detected. As the emitted PL is in the near-infrared region, the developed biosensor has a good signal to noise ratio in biological fluids. One of the diseases associated with abnormal protease activity is pancreatitis. In acute pancreatitis, trypsin concentration could reach up to 84 µg/mL in the urine. For proof of concept, we demonstrate the feasibility of the proposed biosensor for the detection of the abnormal levels of trypsin activity in urine samples.

Folic Acid Functionalized Chlorin e6-Superparamagnetic Iron Oxide Nanocarriers as a Theranostic Agent for MRI-Guided Photodynamic Therapy

2021 ◽  
Vol 17 (2) ◽  
pp. 205-215
Author(s):  
Zhenbo Sun ◽  
Mingfang Luo ◽  
Jia Li ◽  
Ailing Wang ◽  
Xucheng Sun ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Folic Acid ◽  
Iron Oxide ◽  
Near Infrared ◽  
Biological Fluids ◽  
Superparamagnetic Iron Oxide ◽  
Chlorin E6 ◽  
Theranostic Agent

Imaging-guided cancer theranostic is a promising strategy for cancer diagnostic and therapeutic. Photodynamic therapy (PDT), as an approved treatment modality, is limited by the poor solubility and dispersion of photosensitizers (PS) in biological fluids. Herein, it is demonstrated that superparamagnetic iron oxide (SPIO)-based nanoparticles (SCFs), prepared by conjugated with Chlorin e6 (Ce6) and modified with folic acid (FA) on the surface, can be used as versatile drug delivery vehicles for effective PDT. The nanoparticles are great carriers for photosensitizer Ce6 with an extremely high loading efficiency. In vitro fluorescence imaging and in vivo magnetic resonance imaging (MRI) results indicated that SCFs selectively accumulated in tumor cells. Under near-infrared laser irradiation, SCFs were confirmed to be capable of inducing low cell viability of RM-1 cells In vitro and displaying efficient tumor ablation with negligible side effects in tumor-bearing mice models.

Modular synthesis of silicon (IV) phthalocyanine conjugates bearing glycosylated axial ligands

2019 ◽  
Vol 23 (07n08) ◽  
pp. 850-855 ◽  
Author(s):  
Shamus A. L. Cooper ◽  
Kevin W. Graepel ◽  
Ricarda C. Steffens ◽  
David G. Dennis ◽  
Gabriel A. Cambroneo ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Clinical Utility ◽  
Near Infrared ◽  
Therapeutic Potential ◽  
Biological Fluids ◽  
Modular Approach ◽  
Specific Targeting ◽  
Axial Ligands ◽  
Carbohydrate Ligands ◽  
Reliable Methods

Phthalocyanines (Pcs) are near-infrared photosensitizers with therapeutic potential for the treatment of bacterial infections and cancer. However, their clinical utility has been hindered by poor solubility in biological fluids, lack of specificity, and limited clearance from affected tissues. Glycosylated Pcs have the potential to overcome these issues by providing increased solubility and tumor specific targeting. However, reliable methods for their synthesis remains challenging. Here we present our first approach towards the synthesis of a series of silicon (IV) phthalocyanine conjugates bearing axial carbohydrate ligands (CPcCs). The novelty of our approach lies in the installation of axial alkyne ligands which can be functionalized with readily accessible acetyl protected azido glycosides, thus providing a modular approach for the synthesis of these complex macromolecules.

scholarly journals Low-Fouling Substrates for Plasmonic Sensing of Circulating Biomarkers in Biological Fluids

Biosensors ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 63
Author(s):  
Elba Mauriz
Keyword(s):  
Biological Fluids ◽  
Point Of Care ◽  
Disease Onset ◽  
Screening Tools ◽  
Circulating Biomarkers ◽  
Prognostic Information ◽  
Wide Range ◽  
Biomarker Analysis ◽  
Surface Enhanced Raman ◽  
The Impact

The monitoring of biomarkers in body fluids provides valuable prognostic information regarding disease onset and progression. Most biosensing approaches use noninvasive screening tools and are conducted in order to improve early clinical diagnosis. However, biofouling of the sensing surface may disturb the quantification of circulating biomarkers in complex biological fluids. Thus, there is a great need for antifouling interfaces to be designed in order to reduce nonspecific adsorption and prevent inactivation of biological receptors and loss of sensitivity. To address these limitations and enable their application in clinical practice, a variety of plasmonic platforms have been recently developed for biomarker analysis in easily accessible biological fluids. This review presents an overview of the latest advances in the design of antifouling strategies for the detection of clinically relevant biomarkers on the basis of the characteristics of biological samples. The impact of nanoplasmonic biosensors as point-of-care devices has been examined for a wide range of biomarkers associated with cancer, inflammatory, infectious and neurodegenerative diseases. Clinical applications in readily obtainable biofluids such as blood, saliva, urine, tears and cerebrospinal and synovial fluids, covering almost the whole range of plasmonic applications, from surface plasmon resonance (SPR) to surface-enhanced Raman scattering (SERS), are also discussed.

European Bioanalysis Forum recommendation on singlicate analysis for ligand binding assays: time for a new mindset

Bioanalysis ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 273-284 ◽  
Author(s):  
Matthew Barfield ◽  
Joanne Goodman ◽  
John Hood ◽  
Philip Timmerman
Keyword(s):  
Ligand Binding ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Binding Assays ◽  
Bioanalytical Method Validation ◽  
Regulatory Guidelines ◽  
The Status ◽  
Analysis Strategy ◽  
Assay Methods ◽  
Pharmacokinetic Assay

It is well accepted that chromatographic assay methods employ singlicate analysis for toxicokinetic and pharmacokinetic analysis. While conversely, it has been the norm for ligand-binding assays to be run in at least duplicate analyses, stemming mainly from concerns over inherent assay variability and reagent quality. Regulatory guidelines and guidance on bioanalytical method validation has, in the most part, recommended multiple replicates for immunoassays and this has led to the industry being comfortable and familiar with duplicate analysis. Over the last few years, the discussion on whether singlicate analysis is acceptable for ligand-binding assays has grown and the status quo is being challenged for regulated bioanalysis performed using immunoassays. Through interrogation of preclinical and clinical pharmacokinetic assay data from the European Bioanalysis Forum community, the application of a singlicate analysis strategy has shown to have no impact on toxicokinetic and pharmacokinetic parameters when compared with duplicate analysis from the same studies. Therefore, now is the time to adopt a new mindset when it comes to sample analysis for toxicokinetic and pharmacokinetic ligand-binding assays and embrace singlicate analysis in the regulated environment.

scholarly journals Folate Receptor Near-Infrared Optical Imaging Provides Sensitive and Specific Intraoperative Visualization of Nonfunctional Pituitary Adenomas

2018 ◽  
Vol 16 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Steve S Cho ◽  
Ryan Zeh ◽  
John T Pierce ◽  
Jun Jeon ◽  
MacLean Nasrallah ◽  
...  
Keyword(s):  
Predictive Value ◽  
Pituitary Adenomas ◽  
Near Infrared ◽  
Folate Receptor ◽  
P Value ◽  
Fluorescence Signal ◽  
Postoperative Mri ◽  
Nir Fluorescence ◽  
Residual Neoplasm ◽  
Nir Dye

Abstract BACKGROUND Surgical resection is the primary treatment for nonfunctional (NF) pituitary adenomas, but gross-total resection is difficult to achieve in all cases. NF adenomas overexpress folate receptor alpha (FRα). OBJECTIVE To test the hypothesis that we could target FRα for highly sensitive and specific intraoperative detection of NF adenomas using near-infrared (NIR) imaging. METHODS Fourteen patients with NF pituitary adenoma were infused with the folate analog NIR dye OTL38 preoperatively. NIR fluorescence signal-to-background ratio (SBR) was recorded for each tumor during resection of the adenomas. Extent of surgery was not modified based on the presence or absence of fluorescence. Immunohistochemistry was performed to assess FRα expression in all specimens. Magnetic resonance imaging (MRI) was performed postoperatively to assess residual neoplasm. RESULTS Nine adenomas overexpressed FRα and fluoresced with a NIR SBR of 3.2 ± 0.52, whereas the 5 non-FRα-overexpressing adenomas fluoresced with an SBR of 1.5 ± 0.21. Linear regression demonstrated a significant correlation between intraoperative SBR and the FRα expression (P-value < .001). Analysis of 14 margin samples revealed that the surgeon's impression of the tissue had 83% sensitivity, 100% specificity, 100% positive predictive value, and 89% negative predictive value, while NIR fluorescence had 100% for all values. NIR fluorescence accurately predicted postoperative MRI results in 78% of FRα-overexpressing patients. CONCLUSION Preoperative injection of folate-tagged NIR dye provides strong signal and visualization of NF pituitary adenomas. It is 100% sensitive and specific for detecting margin neoplasm and can predict postoperative MRI findings. Our results suggest that NIR fluorescence may be superior to white-light visualization alone and may improve resection rates in NF pituitary adenomas.

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