Self-assembled nanobody-DNA nanomachine conjugate for parathyroid glands intraoperative imaging and parathyroid hormone detection

Abstract

During thyroidectomy, inadvertent parathyroid damage commonly occurs owing to the varying location of the parathyroid glands and their similarity to adipose tissue, lymph nodes, and thyroid nodules. Therefore, in this study, we aimed to develop a novel self-assembled nanobody-DNA nanomachine conjugate probe (PTH-Nb-HCR) for precisely identifying the parathyroid glands and monitoring parathyroid hormone (PTH) levels in patient blood. The probe consists of two components: the first component is the nanobody (Nb)-nucleic acid conjugate PTH-Nb-Trigger, acting as a recognition unit for PTH and capable of initiating the hybridization chain reaction (HCR), whereas the second component comprises the HCR hairpin probes HP1-FAM (with a modified FAM signal molecule at the 5′ end) and HP2. The assembly of the PTH-Nb-HCR fluorescent probe takes only 20 min. Using the probe, the serum PTH level was quantitatively detected in the 0.1–1000 pg/mL range, and the parathyroid glands were rapidly distinguished from adipose, lymphoid, and thyroid tissues within 5 min. We also used this probe for imaging parathyroid glands with hyperparathyroidism. Considering the strong correlation between fluorescence intensity and preoperative serum PTH levels in patients, we anticipate the use of this probe to distinguish normal and hyperfunctional tissues during hyperparathyroidism surgery.