Target Peptide Detection and Measurement Using a Capacitive Immunoprobe Biosensor

Abstract

Source: Kluge, N. et al., Time-Resolved In Vivo Measurement of Neuropeptide Dynamics by Capacitive Immunoprobe in Porcine Heart. J. Vis. Exp.(2022).

This video demonstrates a method for detecting and quantifying peptide transmitters using a capacitive immunoprobe biosensor. The functionalized electrode, coated with antibodies, interacts with peptides of interest, leading to a signal change that allows precise measurement and detection of peptides.

Protocol

1. Capacitive immunoprobe fabrication and functionalization Cut a 25 cm length of perfluoroalkoxy (PFA)-coated platinum wire (see Table of Materials) and strip approximately 5 mm of PFA coating from one end using a scalpel, being careful not to cut into the platinum wire. Insert the stripped end of the platinum wire into a gold-plated 1 mm male connector pin and crimp the connector pin teeth around the stripped end of the platinum wire using needle-nose pliers …

Materials

AgCl disc electrode	Warner Instruments (Holliston, MA)	64-1307
Anti-NPY monoclonal antibody	Abcam, (Cambridge, MA)	ab112473
Custom multichannel amplifier/ 1 MΩ feedback resistor multichannel headstage	NPI Electronic, (Tamm, Germany)	NA	Based on NPI VA-10M multichannel amplifier
Dopamine HCl	Sigma Aldrich (St. Louis, MO)	H8502-10G
Gold-plated male connector pin	AMP-TE Connectivity (Amplimite)	6-66506-1
HEKA LIH 8+8 analog-to-digital/digital-to-analog device	HEKA Elektronik, (Holliston, MA)	NA
Igor Pro data acquisition software, v. 7.08	WaveMetrics, (Lake Oswego, OR)		Software driving command potential and data acquisition was custom written
Masterflex L/S Standard Digital peristaltic pump	Cole Palmer, (Vernon Hills, IL)
PFA-coated platinum wire	A-M Systems, (Sequim, WA)	773000	0.005" bare diameter, 0.008" coated diameter
Silicone elastomer	World Precision Instruments (Sarasota, FL)	SYLG184
Synthetic porcine NPY peptide	Bachem (Torrance, CA)	4011654