Peptide-Based Assemblies on Electrospun Polyamide-6/Chitosan Nanofibers for Detecting Visceral Leishmaniasis Antibodies

Abstract

An alternative label-free electrochemical immunosensor for the rapid detection of Leishmania braziliensis was developed by immobilizing a peptide-based probe of the promastigote surface antigen (PSA-38S) onto electrospun polyamide-6 (PA6)/chitosan nanofibers. An increase in chitosan content in the spinning solution leads to a decrease in the diameter of the formed fibers, whereas the differential scanning calorimetry (DSC) and X-ray diffraction (XRD) data showed a decrease in crystallinity upon increasing the chitosan content in the formulation. In addition, the incorporation of chitosan into the PA6 nanofibers tends to decrease the resistance to the charge-transfer process at the electrode surface. A 40 wt % chitosan content was used for immobilization of the peptide antigen, which was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The detection was performed by measuring the relative change in impedance before and after the anti-Leishmania braziliensis reaction by EIS. Under the optimized conditions, the relative change in impedance was proportional to the logarithmic value of PSA concentrations in the range of 2.5 to 10 pg•mL −1 (r 2 = 0.9946) with a detection limit of 0.2 pg•mL −1 , which was slightly lower than that of the enzyme-linked immunosorbent assay. Additionally, the sensor was tested against two nonspecific antibodies (T. cruzi and β-actin), whereas multivariate analysis using unsupervised pattern recognition through principal component analysis was successfully applied to identification of the pattern relative to each antibody. Finally, the optimized electrochemical immunoassay can be a favorable approach for Leishmania detection tests, as it is able to differentiate negative and positive visceral leishmaniasis human serum samples.

Electrospun Nanofibers for Sensing and Biosensing Applications—A Review

“…where the recognition was based on an interaction between an epitope designed from the antigen and its specific antibody [74]. Polyamide 6 (PA6)/CS NFs were fabricated using the electrospinning technique (diameter in a range of 15-170 nm) and characterized with, i.a., SEM, XRD, and FT-IR.…”

Peptide-Chitosan Engineered Scaffolds for Biomedical Applications

“…Fibrin-specific peptides incorporated into Glycol-chitosan-coated AuNP were reported for CT-based imaging of cerebrovascular thrombi; peptide incorporated systems showed better stability and imaging capability . In another study, PSA-38S (sequence: NH 2 -CTSSA­PVARA­AGTG­DFTE­EQR­TNTL-COOH) electrospun with a polyamide-6/chitosan nanofibers-based biosensor was developed for the detection of visceral leishmaniasis antibodies . A novel bioassay incorporating NOF4, a synthetic peptide, immobilized on a porous chitosan foam via a histidine tag was developed for the capture-purification and detection of ochratoxin A, a natural carcinogenic mycotoxin, and other haptens .…”

“…175 In another study, PSA-38S (sequence: NH 2 -CTSSAPVARAAGTGDFTEEQR-TNTL-COOH) electrospun with a polyamide-6/chitosan nanofibers-based biosensor was developed for the detection of visceral leishmaniasis antibodies. 176 A novel bioassay incorporating NOF4, a synthetic peptide, immobilized on a porous chitosan foam via a histidine tag was developed for the capture-purification and detection of ochratoxin A, a natural carcinogenic mycotoxin, and other haptens. 177 A radiolabeled peptides−chitosan conjugate has been explored for tumor diagnosis.…”

Nanodiagnostics in leishmaniasis: A new frontiers for early elimination

“…The fiber morphology can be modified by altering the (PA6)/chitosan, thus changing the electrochemical characteristics. It is a favorable approach as it can differentiate negative and positive VL from human serum samples (Liberato et al, 2019).…”