Metal-Labeled Aptamers as Novel Nanoprobes for Imaging Mass Cytometry Analysis

Abstract

Imaging mass cytometry (IMC) is an emerging imaging technology that exploits the multiplexed analysis capabilities of the CyTOF mass cytometer to make spatially resolved measurements for tissue sections. In a comprehensive view of tissue composition and marker distribution, recent developments of IMC require highly sensitive, multiplexed assays. Approaching the sensitivity of the IMC technique, we designed a novel type of biocompatible metal-labeled aptamer nanoprobe (MAP), named 167Er-A10-3.2. The small molecular probe was synthesized by conjugating 167Er-polymeric pentetic acid (167Er-DTPA) with an RNA aptamer A10-3.2. For demonstration, 167Er-A10-3.2 was applied for observing protein spatial distribution on prostatic epithelium cell of paraffin embedded Prostatic adenocarcinoma (PaC) tissue sections by IMC technology. The 167Er-A10-3.2 capitalizes on the ability of the aptamer to specifically bind target cancer cells as well as the small size of 167Er-A10-3.2 can accommodate multiple aptamer binding antigen labeled at high density. The detection signal of 167Er-A10-3.2 probe was 3-fold higher than that of PSMA antibody probe for a targeted cell under lower temperature epitope retrieval (37 °C) of PaC tissue. Furthermore, we successfully demonstrated the simultaneously staining ability of aptamer probes in IMC analysis. The successful imaging acquisition using aptamers probes in IMC technology may offer opportunity for the diagnosis of malignancies in the future.

Aptamer Probes Labeled with Lanthanide‐Doped Carbon Nanodots Permit Dual‐Modal Fluorescence and Mass Cytometric Imaging

“…The successful IMC imaging acquisition using MCPs(Ln)‐labeled A10‐3.2 aptamer probe has been previously demonstrated. [ 23 ] From the fluorescence imaging results, the B‐Cdots( 165 Ho)‐A10‐3.2 stained LNCaP cells showed stronger fluorescence intensity compared to the negative PC‐3 cells ( Figure 3 a ), indicating that B‐Cdots( 165 Ho)‐A10‐3.2 showed effective specific targeting ability. The Cy5.5‐A10‐3.2 stained LNCaP and PC‐3 in a side‐by‐side experiment was used as control (Figure 3b ).…”

Aptamer-Targeted Photodynamic Platforms for Tumor Therapy

“…43 MUC1 aptamer or AS1411 can recognize and bind to MUC1 protein or nucleolin, respectively, which are highly expressed on the membrane of a wide range of cancer cells. When these aptamers were conjugated with polymers, 48 nanoparticles, 49,50 biomacromolecules, 51 or small molecules, 52 the obtained complexes could reach cancer cells selectively under the guidance of aptamers, confirming that the targeting and binding capacities of aptamers would be maintained well after a series of simple chemical modifications.…”

Multiplexed Ion Beam Imaging Readout of Single-Cell Immunoblotting

“…We first sought to investigate whether and to what extent metal-tagging affects antibody performance in in-gel immunoassays. For mass spectrometry imaging approaches (e.g., MIBI-TOF) the first step is to stain the sample with a panel of metal-tagged probes. , Therefore, to use MIBI-TOF as a detection method for single-cell immunoblotting assays such as scWB and scIEF, immunoprobing needs to be performed with metal-tagged primary antibodies instead of the conventional untagged primary and fluorophore-tagged secondary antibody probe duo. We hypothesized that metal-tagging may impact the physiochemical properties of an antibody molecule to the detriment of in-gel immunoassay performance.…”