Wide range detection of C-Reactive protein with a homogeneous immunofluorimetric assay based on cooperative fluorescence quenching assisted by gold nanoparticles
BIOSENSORS & BIOELECTRONICS
Authors: Bravin, Carlo; Amendola, Vincenzo
Abstract
Homogeneous sandwich immunofluorimetric assays are valued for the rapid, low-cost and accurate detection of analytes in liquid phase. However, their exploitation with analytes covering a wide range of concentrations is limited by low sensitivity and the hook effect. Here, we describe a homogeneous immunofluorimetric system based on the quenching of fluorescence in a Forster resonance energy transfer (FRET) donor/acceptor couple of antibody functionalized with two different dyes, respectively fluorescein (donor) and eosin (acceptor), which form a sandwich multi-component assembly with antibody-functionalized gold nanoparticles (GNPs) in the presence of the analyte. The resulting cooperative fluorescence quenching is assisted by the GNPs scaffold through the nanomaterial-surface energy transfer (NSET) effect, which gives an extended linear response versus the antigen concentration that is not possible with the bi-component assays. This immunofluorimetric method allows accurate, reproducible and immediate detection of C-reactive protein (CRP) in the wide concentration range of clinical interest (over two orders of magnitude from 3.5 to 455 nM, 0.4-52 mg/L), without the hook effect. Moreover, the method does not require sample treatment or washing steps. The concept of this multi-component FRET/NSET fluorescence quenching system can be extended to any analyte amenable to the detection with homogeneous sandwich assays.
Primary Dysmenorrhea in Relation to Oxidative Stress and Antioxidant Status: A Systematic Review of Case-Control Studies
ANTIOXIDANTS
Authors: Szmidt, Maria Karolina; Granda, Dominika; Sicinska, Ewa; Kaluza, Joanna
Abstract
Primary dysmenorrhea is defined as painful menstrual cramps of uterine origin in the absence of pelvic pathology and is the most common gynecological disorder among women of reproductive age. The aim of this study was to systematically review case-control studies that have investigated the oxidative stress, antioxidant status, and inflammation markers among women with primary dysmenorrhea and controls. The study protocol was registered with PROSPERO (no. CRD42020183104). By searching PubMed and Scopus databases as well as reference lists, six case-control studies with fifteen eligible markers (seven oxidative stress, seven antioxidant status, one inflammation) were included in this review. The quality of the included studies was assessed as medium or high. The systematic review included 175 women with primary dysmenorrhea and 161 controls. The results indicate an elevated level of oxidative stress, especially of lipid peroxidation among dysmenorrheal women. For the antioxidant status, limited evidence was found for a lower status among primary dysmenorrhea women, and only one study examined one inflammation marker (hs-CRP), which makes it impossible for such a conclusion. To establish whether oxidative stress, antioxidant status or inflammation participate in the pathophysiology of primary dysmenorrhea, high-quality studies with larger study groups and clear case definitions are needed.