Disposable Passive Electrochemical Microfluidic Device for Diagnosis of Congenital Disorders of Glycosylation

Abstract

A disposable pump-free electrochemical microfluidic device made by using a multilayer lamination technique is proposed for diagnosis of glycosylation disorders. Thanks to the stacking of polyethylene terephthalate (PET) films and double adhesive layers, it is possible to create a geometry that allows the filling of the tailored channels in a fixed time. In the main channel of this passive microfluidic device, the necessary steps to perform the electrochemical determination of transferrin are performed: labeling of the protein with Os (VI) complex (electrochemical tag), washing with water of the osmium residues and electro-chemical detection by adsorptive transfer stripping square wave voltammetry. Electrochemical detection released two electrochemical signals: one from Os (VI) complex due to carbohydrates at À 0.9 V, and other from the intrinsic electrochemical signal of glycoprotein due to the amino acids at + 0.8 V. The ratio between them establishes an indicator of the degree of glycosylation (called electrochemical index of glycosylation). The method was successfully applied to the analysis of clinical samples from patients with congenital disorders of glycosylation.

Paper-Based Analytical Devices for Accurate Assessment of Transferrin Saturation in Diagnosed Clinical Samples from Ischemic Stroke Patients

“…However, the limit of detection (LOD) was 2 μg mL –1 (calculated as 3 s a / b , where s a is the standard deviation of the intercept), which is not enough to detect iron in human serum (normal range from 0.7 to 1.7 μg mL –1 ) . However, this is not a problem when serum samples were analyzed because an immunopurification step was implemented for the isolation of Tf using anti-Tf-MBs, , yielding a 10 times preconcentration (Tf present in 150 μL serum is concentrated in a 15 μL solution during the immunopurification). In this sense, the LOD of the overall method was reduced from 2 to 0.2 μg mL –1 .…”

“…Anti-Tf-MBs were used for Tf isolation in serum samples and were prepared according to the literature. , This step allowed us to isolate Tf-bound iron from the rest of the iron (III) species present in serum, ensuring that we only measured iron bound to Tf in the following steps Immunoreaction: 5 μL of anti-Tf-MBs was resuspended in 150 μL of serum sample (which contained Tf) and this vial was incubated at 25 °C and 950 rpm for 45 min (Eppendorf ThermoMixer C, Hamburg, Germany). Cleaning: the vial was placed on the magnet holding block for 2 min, and then, the supernatant was removed.…”

“…Anti-Tf-MBs were used for Tf isolation in serum samples and were prepared according to the literature. 33,34 This step allowed us to isolate Tf-bound iron from the rest of the iron (III) species present in serum, ensuring that we only measured iron bound to Tf in the following steps. (ii) Cleaning: the vial was placed on the magnet holding block for 2 min, and then, the supernatant was removed.…”

Digital manufacturing for accelerating organ-on-a-chip dissemination and electrochemical biosensing integration

“…Sierra et al developed carbon nanomaterial-based EMDs for the detection of α1-acid glycoprotein in serum samples 120 and for diagnosis of glycosylation disorders. 121 Other examples of EMDs for relevant clinical applications include the electrochemical arrays developed by Faria's group for the sensitive detection of Salmonella typhimurium 122 and biomarkers of breast cancer 123 and Alzheimer's disease. 124 More recently, Asri et al employed a very similar approach to construct a gold-based electrochemical microfluidic platform and validated it towards H 2 O 2 direct reduction and H 2 O 2 produced by glucose oxidase.…”