Exploiting the Catalytic Ability of Polydopamine-Remodeling Gold Nanoparticles toward the Naked-Eye Detection of Cancer Cells at a Single-Cell Level

Abstract

In this study, a catalytic polydopamine-remodeling gold nanoparticle sensitized with an antinucleolin AS1411 probe (pAu nanoprobe) is synthesized, where the surface of the gold nanoparticles (AuNPs) is modified with a spontaneous selfpolymerization of a polydopamine coating that imparts the probe functionalization ability and antispecific protein binding while the intrinsic catalytic property of the AuNPs is preserved. The functionalized AS1411 probe exerts specific recognition with nucleolin protein that is found to be overexpressed on the surface of breast cancer cells (MDA-MB-231). Scanning electron microscopy (SEM) confirms that the specific binding of the pAu nanoprobe occurs at the cancer cell surface. Taking advantage of the catalytic ability of the pAu nanoprobe in reducing blue-colored methylene blue (MB) to colorless leuco-MB, a colorimetric biosensing platform is established based on the accessible catalytic active sites on the pAu nanoprobe toward MB. The specific binding inhibits the pAu nanoprobe from efficiently catalyzing the reduction of MB, resulting in a "turn-of f" catalytic biosensing platform. The catalytic conversion of MB is inversely proportional to the concentration of the nucleolin protein and the cancer cells, yielding a detection limit of 15 pM of the nucleolin protein and two cancer cells. The presence of five orders of magnitude higher concentration of bovine serum albumin hardly affects the catalytic ability of the pAu nanoprobe, that is, 88% catalytic ability is still preserved, which validates the specificity of the proposed pAu nanoprobe. In particular, a distinct color contrast creates a significant signal-to-noise ratio so as to enable single-cell level detection of two cancer cells by naked-eye judgment. Moreover, the undiluted, real human serum samples spiked with the cancer cells were examined with an impressive recovery of 94 ± 0.3%, which holds great promise in cancer cell screening.

Aptamer-Engineered Cu2O Nanocubes as a Surface-Modulated Catalytic Optical Sensor for Lung Cancer Cell Detection

“…In addition, consistency was also shown as in the elemental mapping results by EDX (Cu, P, and N), while the cancer cells presented the characteristic elements of P and N; the bound Apt-Cu 2 O, in addition to the Cu element, also displayed the presence of P and N elements, which are ascribed to the successful modification of aptamer on Apt-Cu 2 O nanocubes (Figure S3). In addition, the binding pattern of the Cu 2 O nanocubes exhibits an aggregated morphology, which may be ascribed to the clustering of surface nucleolin protein in a lipid raft membrane, in agreement with previous studies. ,, Obviously, the aggregated Apt-Cu 2 O nanocubes on the cancer cells led to a decreased active surface responsible for the catalytic performance. We further examined if such a binding event was able to induce a concentration-dependent catalytic performance of Apt-Cu 2 O nanocubes upon sensing of different lung cancer cells.…”

“…In addition, the binding pattern of the Cu 2 O nanocubes exhibits an aggregated morphology, which may be ascribed to the clustering of surface nucleolin protein in a lipid raft membrane, in agreement with previous studies. 39,42,43 Obviously, the aggregated Apt-Cu 2 O nanocubes on the cancer cells led to a decreased active surface responsible for the catalytic performance. We further examined if such a binding event was able to induce a concentration-dependent catalytic performance of Apt-Cu 2 O nanocubes upon sensing of different lung cancer cells.…”

Boronates as hydrogen peroxide–reactive warheads in the design of detection probes, prodrugs, and nanomedicines used in tumors and other diseases

“…Thus, this section describes several studies in which boronate-associated nanoparticles were devised and applied to biomedical domains. Gold nanoparticles (AuNPs) have been widely employed as a marker for biological molecule recognition because of their excellent physicochemical properties and controllable optical features [89][90][91][92]. One study used AuNPs into which a mannoside-boronate-sul de (MBS) ligand had been incorporated to achieve speci c H 2 O 2 detection (Fig.…”

“Light-On” Fluorescent Nanoprobes for Monitoring Dynamic Distribution of Cellular Nucleolin During Pyroptosis

“…Nucleolin (NCL) is a potential target for cancer therapy. NCL is involved in the control of RNA and DNA metabolism, and its overexpression promotes the proliferation and survival of cancer cells as well as boosts tumorigenesis by promoting tumor invasion and angiogenesis, which has attracted more and more attention recently. , A variety of methods have been reported to detect NCL including colorimetry, electrochemiluminescence, mass spectrum, and so on. In addition, commercial NCL detection assay kits are mainly based on the method of ELISA.…”