Immunosensor for HIV-1 diagnostics based on immobilization of the antigenic peptide p24-3 into liposomes.
In this work we developed an immunosensor for HIV-1 diagnostics that exploits the biorecognition between the antibody anti-p24 and the antigenic peptide p24-3 (AMATLRAEQASQEVKNWMTETL- LVQNA) derived from the HIV-1 p24 protein. p24-3 was encapsulated in phospholipid liposomes and immobilized in layer-by-layer (LbL) films produced with polyethyleneimine (PEI). The incorporation of p24-3 into liposomes was investigated using circular dichroism (CD) spectroscopy, from which an increase in the alpha helix conformation could be noted. The maximum fluorescence emission for p24-3 occurred at 340 nm in solution, compatible with the tryptophan residue being exposed to the solvent, and at 335 and 322 nm when in liposomes and PEI/p24-3-liposome LbL films, respectively. This blue shift is consistent with the tryptophan being in a partially buried environment. With the preserved structure in the LbL films, p24-3 could recognize the anti-p24 antibody in impedance spectroscopy measurements. Therefore, LbL films containing p24-3 may be suitable for detecting HIV-1 in a low-cost, easy-to-use immunosensing assay.
Marli L
ML
Moraes
Valquíria C
VC
Rodrigues
Juliana C
JC
Soares
Marystela
M
Ferreira
Nara C
NC
de Souza
Osvaldo N
ON
Oliveira
D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D016655:HIV Core Protein p24 / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D015658:HIV Infections / Q000175:diagnosis*; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods; D008081:Liposomes / Q000737:chemistry*; D008954:Models, Biological; D008969:Molecular Sequence Data; D011094:Polyethyleneimine / Q000737:chemistry
D000914:Antibodies, Viral; D016655:HIV Core Protein p24; D055767:Immobilized Proteins; D008081:Liposomes; D011094:Polyethyleneimine