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Postoperative tumor recurrence and metastases often lead to cancer treatment failure. Here, we develop a local embedded photodynamic immunomodulatory DNA hydrogel for early warning and inhibition of postoperative tumor recurrence. The DNA hydrogel contains PDL1 aptamers that capture and enrich in situ relapsed tumor cells, increasing local ATP concentration to provide a timely warning signal. When a positive signal is detected, local laser irradiation is performed to trigger photodynamic therapy to kill captured tumor cells and release tumor-associated antigens (TAA). In addition, reactive oxygen species break DNA strands in the hydrogel to release encoded PDL1 aptamer and CpG, which together with TAA promote sufficient systemic antitumor immunotherapy. In a murine model where tumor cells are injected at the surgical site to mimic tumor recurrence, we find that the hydrogel system enables timely detection of tumor recurrence by enriching relapsed tumor cells to increase local ATP concentrations. As a result, a significant inhibitory effect of approximately 88.1% on recurrent tumors and effectively suppressing metastasis, offering a promising avenue for timely and effective treatment of postoperative tumor recurrence. Decreased survival after surgery is often associated to post-operative tumor recurrence and metastasis. Here the authors describe a DNA hydrogel enabling monitoring of tumor recurrence and spatiotemporally controlled photodynamic immunotherapy to prevent post-operative tumor recurrence and metastasis. [ABSTRACT FROM AUTHOR]

Extracellular vesicles (EV) have attracted increasing attention as tumour biomarkers due to their unique biological property. However, conventional methods for EV analysis are mainly based on bulk measurements, which masks the EV‐to‐EV heterogeneity in tumour diagnosis and classification. Herein, a localized fluorescent imaging method (termed Digital Profiling of Proteins on Individual EV, DPPIE) was developed for analysis of multiple proteins on individual EV. In this assay, an anti‐CD9 antibody engineered biochip was used to capture EV from clinical plasma sample. Then the captured EV was specifically recognized by multiple DNA aptamers (CD63/EpCAM/MUC1), followed by rolling circle amplification to generate localized fluorescent signals. By‐analyzing the heterogeneity of individual EV, we found that the high‐dimensional data collected from each individual EV would provide more precise information than bulk measurement (ELISA) and the percent of CD63/EpCAM/MUC1‐triple‐positive EV in breast cancer patients was significantly higher than that of healthy donors, and this method can achieve an overall accuracy of 91%. Moreover, using DPPIE, we are able to distinguish the EV between lung adenocarcinoma and lung squamous carcinoma patients. This individual EV heterogeneity analysis strategy provides a new way for digging more information on EV to achieve multi‐cancer diagnosis and classification. [ABSTRACT FROM AUTHOR]

We report a transcription aptasensor by using a light-up RNA aptamer. It allows for sensitive, label-free and culture-free detection of intact foodborne pathogens, and no separation, purification or enrichment processes are involved. [ABSTRACT FROM AUTHOR]

Highlights • Structure-switching aptamer probe was designed to achieve enzyme-free amplification. • Detection process for AFB 1 could be finished within 1 min. • All detection process could be conducted in one test-tube at a constant temperature. • AFB 1 contamination in fluid or liquid food samples were accurately detected. Abstract Aptamer probes provide an opportunity for achieving rapid and on-site detection of food contaminants. Herein, we proposed a general design strategy for aptamer probes enabling enzyme-free amplified, ultrafast and one-test tube homogeneous detection of aflatoxin B 1 (AFB 1). The key feature of the aptamer probe is designed with dual-terminal proximity structures, allowing the binding of one molecule to light up two fluorophores, leading to enzyme-free amplification and a remarkable improvement of signal to background ratio and sensitivity for AFB 1 detection. This aptamer probe could accommodate quick response to AFB 1 , and the detection process could be finished within 1 min, ranking one of the quickest assays for AFB 1. AFB 1 detection of broad bean paste and peanut oil conferred satisfactory recoveries ranging from 90.3% to 114.8%. Contributed to the generality and simplicity of the design strategy, this structure-switching probe could potentially act as a general platform of on-site detection for food safety. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission (AIE) dyes are promising for labeling nucleic acid probes. Aptamer is one of the most appealing nucleic acid probes, and may enable to output signal response to target molecules by the direct use of single aptamer sequence. However, the concise sensing platform is often suffered from low sensitivity. In response, by the adoption of AIE dyes, we propose an intrinsic conformation response-leveraged aptamer probe (iconAptamer) for aflatoxin B 1 (AFB 1) detection. The design strategy lies in the synergetic utilization of AIE and fluorescence resonance energy transfer (FRET) effects. AIE dyes confer a much higher sensitivity for monitoring the response of aptamer towards AFB 1 compared to traditional DNA intercalation dyes. FRET process between AIE dyes and the terminal-labeled fluorophore would induce a distance effect in the structure-switching process, further leveraging the response signal. Consequently, the sensitivity of the aptamer probe was dramatically improved by over 2 orders. IconAptamer allowed to mix-to-read detection of AFB 1 contaminations at room temperature. The application of iconAptamer for AFB 1 detection in food and environmental samples has been demonstrated, with recovery rates of 91.8%–111.1%. IconAptamer would provide a simple, fast, convenient, and cost-effective platform for food safety control and environmental monitoring by broadening the target species. Based on aggregation-induced emission dye and FRET process for leveraging the Intrinsic conformation response of aptamer toward targets, a single-aptamer sequence-based assay was established, which enables sensitive and mix-to-read detection of aflatoxin B 1. Image 1 • A sensitive single-strand aptamer probe was built using AIE dye and FRET process. • Achieving mix-to-read analysis of aflatoxin B 1 , thus well fit for on-site detection. • Potential application for food safety control and environmental monitoring. [ABSTRACT FROM AUTHOR]