Ultrasensitive antibody-aptamer plasmonic biosensor for malaria biomarker detection in whole blood

• Published in: Nature communications Vol. 11; no. 1; pp. 6134 - 10
• Main Authors: Minopoli, Antonio, Della Ventura, Bartolomeo, Lenyk, Bohdan, Gentile, Francesco, Tanner, Julian A., Offenhäusser, Andreas, Mayer, Dirk, Velotta, Raffaele
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.12.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 631/1647/1888/1890; 631/1647/1888/2005; 631/1647/664; 631/61/350/2251; 631/61/350/59; 9/10; Antibodies; Aptamers; Aptamers, Nucleotide - chemistry; Aptamers, Nucleotide - genetics; Arrays; Biomarkers; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensors; Block copolymers; Blood; Conformation; Diagnostic systems; Enzyme-linked immunosorbent assay; Fluorescence; Gold; Gold - chemistry; Humanities and Social Sciences; Humans; Immobilization; Immunoassay - instrumentation; Immunoassay - methods; Immunoassays; Immunosensors; L-Lactate dehydrogenase; L-Lactate Dehydrogenase - blood; L-Lactate Dehydrogenase - genetics; Lactate dehydrogenase; Lactic acid; Lattice parameters; Malaria; Malaria, Falciparum - blood; Malaria, Falciparum - diagnosis; Malaria, Falciparum - parasitology; Metal Nanoparticles - chemistry; Micelles; multidisciplinary; Nanolithography; Nanoparticles; Nucleic acids; Photochemicals; Plasmodium falciparum; Plasmodium falciparum - enzymology; Plasmodium falciparum - genetics; Plasmodium falciparum - isolation & purification; Plasmonics; Pretreatment; Protozoan Proteins - blood; Protozoan Proteins - genetics; Science; Science (multidisciplinary); Substrates; Vector-borne diseases
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-19755-0

Development of plasmonic biosensors combining reliability and ease of use is still a challenge. Gold nanoparticle arrays made by block copolymer micelle nanolithography (BCMN) stand out for their scalability, cost-effectiveness and tunable plasmonic properties, making them ideal substrates for fluorescence enhancement. Here, we describe a plasmon-enhanced fluorescence immunosensor for the specific and ultrasensitive detection of Plasmodium falciparum lactate dehydrogenase ( Pf LDH)—a malaria marker—in whole blood. Analyte recognition is realized by oriented antibodies immobilized in a close-packed configuration via the photochemical immobilization technique (PIT), with a top bioreceptor of nucleic acid aptamers recognizing a different surface of Pf LDH in a sandwich conformation. The combination of BCMN and PIT enabled maximum control over the nanoparticle size and lattice constant as well as the distance of the fluorophore from the sensing surface. The device achieved a limit of detection smaller than 1 pg/mL (<30 fM) with very high specificity without any sample pretreatment. This limit of detection is several orders of magnitude lower than that found in malaria rapid diagnostic tests or even commercial ELISA kits. Thanks to its overall dimensions, ease of use and high-throughput analysis, the device can be used as a substrate in automated multi-well plate readers and improve the efficiency of conventional fluorescence immunoassays. Reliable plasmonic biosensors with high throughput and ease of use are highly sought after. Here, the authors report a plasmon-enhanced fluorescence antibody-aptamer biosensor based on a gold nanoparticle array, and demonstrate its use for effective specific detection of a malaria marker, at femtomolar level, in whole blood.