Near‐Infrared Afterglow Semiconducting Nano‐Polycomplexes for the Multiplex Differentiation of Cancer Exosomes

Abstract

The detection of exosomes is promising for the early diagnosis of cancer. However, the development of suitable optical sensors remains challenging. We have developed the first luminescent nanosensor for the multiplex differentiation of cancer exosomes that bypasses real‐time light excitation. The sensor is composed of a near‐infrared semiconducting polyelectrolyte (ASPN) that forms a complex with a quencher‐tagged aptamer. The afterglow signal of the nanocomplex (ASPNC), being initially quenched, is turned on in the presence of aptamer‐targeted exosomes. Because detection of the afterglow takes place after the excitation, background signals are minimized, leading to an improved limit of detection that is nearly two orders of magnitude lower than that of fluorescence detection in cell culture media. Also, ASPNC can be easily tailored to detect different exosomal proteins by changing the aptamer sequence. This enables an orthogonal analysis of multiple exosome samples, potentially permitting an accurate identification of the cellular origin of exosomes for cancer diagnosis.

<p>Cancer-Derived Exosomes: Their Role in Cancer Biology and Biomarker Development</p>

“…[26][27][28] The latest biosensing technologies, such as afterglow sensors with aptamer-based signal amplification, improve the limit of detection (LOD) that is nearly two orders of magnitude lower than that of fluorescence methods. 29 With the advent of these sensitive biosensors, the LOD can practically be improved to 10 2 exosomes per milliliter.…”

Self-Illuminating Agents for Deep-Tissue Optical Imaging

“…Bioluminescence and chemiluminescence require respective enzyme or ROS to oxidize their substrate to generate luminescence, and thus the imaging signal was easily disturbed by cellular environment and substrate availability. Different from bioluminescence and chemiluminescence imaging, afterglow imaging detects slow release of photons from the chemical or energy defects stored by light pre-irradiation (Xu et al, 2016; Zhen et al, 2018; Lyu et al, 2019). The separation of light irradiation and signal collection circumvent the autofluorescence, inducing remarkable improvement of imaging sensitivity and SBR.…”

Grafted semiconducting polymer amphiphiles for multimodal optical imaging and combination phototherapy

“…[32][33][34][35] NIR-absorbing SPNs can be applied in photoacoustic (PA) imaging of stem cells, 36 vasculature, [37][38][39] tumor, [40][41][42][43][44] lymph nodes, 25,45 ROS 46,47 and pH. 48 Chemiluminescence and aerglow imaging of tumor, [49][50][51][52][53] reactive oxygen species (ROS), 54,55 temperature 56 and immunoactivation 57 can also be conducted by using SPNs with unique structures. In addition, SPNs with a high photothermal conversion efficiency (PCE) or singlet oxygen quantum yield can be used for PTT or PDT, respectively.…”