Surface plasmon resonance assay for label-free and selective detection of hiv-1 p24 protein

The early detection of the human immunodeficiency virus (HIV) is of paramount importance to achieve efficient therapeutic treatment and limit the disease spreading. In this perspective, the assessment of biosensing assay for the HIV-1 p24 capsid protein plays a pivotal role in the timely and selective detection of HIV infections. In this study, multi-parameter-SPR has been used to develop a reliable and label-free detection method for HIV-1 p24 protein. Remarkably, both physical and chemical immobilization of mouse monoclonal antibodies against HIV-1 p24 on the SPR gold detecting surface have been characterized for the first time. The two immobilization techniques returned a capturing antibody surface coverage as high as (7.5 ± 0.3) × 1011 molecule/cm2 and (2.4 ± 0.6) × 1011 molecule/cm2, respectively. However, the covalent binding of the capturing antibodies through a mixed self-assembled monolayer (SAM) of alkanethiols led to a doubling of the p24 binding signal. Moreover, from the modeling of the dose-response curve, an equilibrium dissociation constant KD of 5.30 × 10−9 M was computed for the assay performed on the SAM modified surface compared to a much larger KD of 7.46 × 10−5 M extracted for the physisorbed antibodies. The chemically modified system was also characterized in terms of sensitivity and selectivity, reaching a limit of detection of (4.1 ± 0.5) nM and an unprecedented selectivity ratio of 0.02

Printed, cost-effective and stable poly(3-hexylthiophene) electrolyte-gated field-effect transistors

14siOrganic bioelectronic sensors based on an electrolyte gated field-effect transistor are gaining momentum due to their extraordinary high-performance level that enables label-free selective single-molecule detection of both genomic and protein biomarkers with a millimeter-wide electrolyte-gated field-effect transistor (EGOFET) device. The organic semiconductor channel material used so far is a spin-coated regio-regular poly(3-hexylthiophene) (P3HT). Of paramount importance is to design an EGOFET sensor that is stable and cost-effective. To address the latter feature, an ink-jet printed regio-regular P3HT film is here investigated as the channel material. Moreover, the EGOFET device structure is intended to comprise a coplanar lateral gate electrode that enables mechanical and electrical stability. Overall, the structure is compatible with large area processing so it can be fabricated at low-costs and can be operated continuously for eight days. Additionally, systematic optical and Raman characterization of the P3HT film proves that the printing process results in a film with a low energetic disorder (better π-π stacking in the crystalline regions) that likely enables stable operation. However, the higher quality crystalline regions (as compared to a spin-coated film) are dispersed in a more significant fraction of the amorphous disordered material with a larger amount of trap states. The higher crystalline order is ascribed to the higher boiling point and slower evaporation of the ortho-dichlorobenzene solvent used in the printing process. Overall, the present study provides a systematic insight into the structure-property correlations, essential to design a well-functioning and cost-effective EGOFET for high-performance electronic biosensing. It also provides one of the few investigations comparing the features characterizing a spin-coated and an ink-jet printed P3HT film. This journal isnonenoneBlasi D.; Viola F.; Modena F.; Luukkonen A.; MacChia E.; Picca R.A.; Gounani Z.; Tewari A.; Osterbacka R.; Caironi M.; Kovacs Vajna Z.M.; Scamarcio G.; Torricelli F.; Torsi L.Blasi, D.; Viola, F.; Modena, F.; Luukkonen, A.; Macchia, E.; Picca, R. A.; Gounani, Z.; Tewari, A.; Osterbacka, R.; Caironi, M.; Kovacs Vajna, Z. M.; Scamarcio, G.; Torricelli, F.; Torsi, L

Single-Molecule Bioelectronic Label-Free Assay of both Protein and Genomic Markers of Pancreatic Mucinous Cysts’ in Whole Blood Serum

15siThe timely diagnosis of cystic pancreatic cancer precursors is of utmost importance to improve patients’ low survival rate. Fine-needle aspiration cytology is endowed with low diagnostic sensitivity, while more effective is the assay of markers, such as a mutated KRAS, in the cyst fluids. Next-generation sequencing, detecting down to a single copy of a genomic marker, enables early diagnosis but the diagnostic sensitivity of high-grade cysts, likely to become malignant, is low. Assaying both mutated KRAS and MUC1 protein markers can improve diagnostic accuracy. Their detection in blood would also be minimally invasive. Here, the mucinous lesions markers, KRAS and MUC1, are both successfully assayed in blood serum at the physical limit with the label-free “Single-Molecule assay with a large Transistor—SiMoT.” This is a compelling proof of principle that the SiMoT platform holds high potential to enable a timely, minimally invasive, and accurate diagnosis of pancreatic cancer precursor cysts.nonenoneMacchia E.; Sarcina L.; Driescher C.; Gounani Z.; Tewari A.; Osterbacka R.; Palazzo G.; Tricase A.; Kovacs Vajna Z.M.; Viola F.; Modena F.; Caironi M.; Torricelli F.; Esposito I.; Torsi L.Macchia, E.; Sarcina, L.; Driescher, C.; Gounani, Z.; Tewari, A.; Osterbacka, R.; Palazzo, G.; Tricase, A.; Kovacs Vajna, Z. M.; Viola, F.; Modena, F.; Caironi, M.; Torricelli, F.; Esposito, I.; Torsi, L