TY - JOUR
T1 - Plasmonic Single-Molecule Affinity Detection at 10-20 Molar
AU - Macchia, Eleonora
AU - Franco, Cinzia Di
AU - Scandurra, Cecilia
AU - Sarcina, Lucia
AU - Piscitelli, Matteo
AU - Catacchio, Michele
AU - Caputo, Mariapia
AU - Bollella, Paolo
AU - Scamarcio, Gaetano
AU - Torsi, Luisa
PY - 2025/1/23
Y1 - 2025/1/23
N2 - DNA can be readily amplified through replication, enabling the detection of a single-target copy. A comparable performance for proteins in immunoassays has yet to be fully assessed. Surface-plasmon-resonance (SPR) serves as a probe capable of performing assays at concentrations typically around 10⁻⁹ molar. In this study, plasmonic single-molecule assays for both proteins and DNA are demonstrated, achieving limits-of-detections (LODs) as low as 10⁻2⁰ molar (1 ± 1 molecule in 0.1 mL), even in human serum, in 1 h. This represents an improvement in typical SPR LODs by eleven orders-of-magnitude. The single-molecule SPR assay is achieved with a millimeter-wide surface functionalized with a physisorbed biolayer comprising trillions of recognition-elements (antibodies or protein–probe complexes) which undergo an acidic or alkaline pH-conditioning. Potentiometric and surface-probing imaging experiments reveal the phenomenon underlying this extraordinary performance enhancement. The data suggest an unexplored amplification process within the biomaterial, where pH-conditioning, driving the biolayer in a metastable state, induces a self-propagating aggregation of partially misfolded proteins, following single-affinity binding. This process triggers an electrostatic rearrangement, resulting in the displacement of a charge equivalent to 1.5e per 102 recognition elements. Such findings open new opportunities for reliable SPR-based biosensing at the physical detection limits, with promising applications in point-of-care plasmonic systems.
AB - DNA can be readily amplified through replication, enabling the detection of a single-target copy. A comparable performance for proteins in immunoassays has yet to be fully assessed. Surface-plasmon-resonance (SPR) serves as a probe capable of performing assays at concentrations typically around 10⁻⁹ molar. In this study, plasmonic single-molecule assays for both proteins and DNA are demonstrated, achieving limits-of-detections (LODs) as low as 10⁻2⁰ molar (1 ± 1 molecule in 0.1 mL), even in human serum, in 1 h. This represents an improvement in typical SPR LODs by eleven orders-of-magnitude. The single-molecule SPR assay is achieved with a millimeter-wide surface functionalized with a physisorbed biolayer comprising trillions of recognition-elements (antibodies or protein–probe complexes) which undergo an acidic or alkaline pH-conditioning. Potentiometric and surface-probing imaging experiments reveal the phenomenon underlying this extraordinary performance enhancement. The data suggest an unexplored amplification process within the biomaterial, where pH-conditioning, driving the biolayer in a metastable state, induces a self-propagating aggregation of partially misfolded proteins, following single-affinity binding. This process triggers an electrostatic rearrangement, resulting in the displacement of a charge equivalent to 1.5e per 102 recognition elements. Such findings open new opportunities for reliable SPR-based biosensing at the physical detection limits, with promising applications in point-of-care plasmonic systems.
KW - Plasmonic sensors
KW - Single-molecule sensing
KW - single-molecule with a large transistor (SiMoT)
KW - Surface probing techniques
KW - Surface-plasmon-resonance
UR - https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=aboakademi&SrcAuth=WosAPI&KeyUT=WOS:001402364800001&DestLinkType=FullRecord&DestApp=WOS_CPL
U2 - 10.1002/adma.202418610
DO - 10.1002/adma.202418610
M3 - Article
C2 - 39846333
SN - 0935-9648
JO - Advanced Materials
JF - Advanced Materials
M1 - 2418610
ER -