An Intelligent DNA Nanoreactor for Easy-to-Read In Vivo Tumor Imaging and Precise Therapy.

Nanomaterial-based in vivo tumor imaging and therapy have attracted extensive attention; however, they suffer from the unintelligent "always ON" or single-parameter responsive signal output, substantial off-target effects, and high cost. Therefore, achieving in vivo easy-to-read tumor imaging and precise therapy in a multi-parameter responsive and intelligent manner remains challenging. Herein, an intelligent DNA nanoreactor (iDNR) was constructed following the "AND" Boolean logic algorithm to address these issues. iDNR-mediated in situ deposition of photothermal substance polydopamine (PDA) can only be satisfied in tumor tissues with abundant membrane protein biomarkers "AND" hydrogen peroxide (H2 O2 ). Therefore, intelligent temperature-based in vivo easy-to-read tumor imaging is realized without expensive instrumentation, and its diagnostic performance matches with that of flow cytometry, and photoacoustic imaging. Moreover, precise photothermal therapy (PTT) of tumors could be achieved via intelligent heating of tumor tissues. The precise PTT of primary tumors in combination with immune checkpoint blockade (ICB) therapy suppresses the growth of distant tumors and inhibits tumor recurrence. Therefore, highly programmable iDNR is a powerful tool for intelligent biomedical applications.

Aptamer-based self-assembled nanomicelle enables efficient and targeted drug delivery.

Nucleic acid aptamer-based nanomicelles have great potential for nanomedicine and nanotechnology applications. However, amphiphilic aptamer micelles are known to be inherently unstable upon interaction with cell membranes in the physiological environment, thus potentially compromising their specific targeting against cancer cells. This flaw is addressed in the present work which reports a superstable micellar nanodelivery system as an amphiphilic copolymer self-assembled micelle composed of nucleic acid aptamer and polyvalent hydrophobic poly(maleic anhydride-alt-1-octadecene) (C18PMH). Using Ce6 as a drug model, these C18-aptamer micelles exhibit efficient tumor-targeting and -binding ability, facilitating the entry of Ce6 into targeted cells for photodynamic therapy. In addition, they can be loaded with other hydrophobic drugs and still demonstrate favorable therapeutic effects. As such, these C18-aptamer micelles can serve as a universal platform for loading multiple drugs, providing a safer and more effective solution for treating cancer.

Metal-DNA Nanocomplexes Enhance Chemo-dynamic Therapy by Inhibiting Autophagy-Mediated Resistance.

Chemo-dynamic therapy (CDT) based on the Fenton or Fenton-like reaction has emerged as a promising approach for cancer treatment. However, autophagy-mediated self-protection mechanisms of cancer cells pose a significant challenge to the efficacy of CDT. Herein, we developed metal-DNA nanocomplexes (DACs-Mn) to enhance CDT via DNAzyme inhibition of autophagy. Specifically, Mn-based catalyst in DACs-Mn was used to generate highly hydroxyl radicals (⋅OH) that kill cancer cells, while the ATG5 DNAzyme incorporated into DACs-Mn inhibited the expression of autophagy-associated proteins, thereby improving the efficacy of CDT. By disrupting the self-protective pathway of cells under severe oxidative stress, this novel approach of DACs-Mn was found to synergistically enhance CDT in both in vitro and in vivo models, effectively amplifying tumor-specific oxidative damage. Notably, the Metal-DNA nanocomplexes can also induce immunogenic cell death (ICD), thereby inhibiting tumor metastasis. Specifically, in a bilateral tumor model in mice, the combined approach of CDT and autophagy inhibition followed by immune checkpoint blockade therapy shown significant potential as a novel and effective treatment modality for primary and metastatic tumors.

Label-Free Colorimetric Method for Detection of Vibrio parahaemolyticus by Trimming the G-Quadruplex DNAzyme with CRISPR/Cas12a.

Vibrio parahaemolyticus (V. parahaemolyticus), which may cause gastrointestinal disorders in humans, is a pathogen commonly found in seafood. There are many methods for detecting V. parahaemolyticus, yet they have some shortcomings, such as high cost, labor-intensiveness, and complicated operation, which are impractical for resource-limited settings. Herein, we present a sequence-specific, label-free, and colorimetric method for visual detection of V. parahaemolyticus. This method utilizes CRISPR/Cas12a to specifically recognize the loop-mediated isothermal amplification (LAMP) products for further trans-cleaving the G-quadruplex DNAzyme and depriving its peroxidase-mimicking activity. In this way, the results can be directly observed with the naked eyes via the color development of 2,2'-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS2-), which displays colorless for positive samples while green for target-free samples. We term such Cas12a-crRNA preventing ABTS2- from developing color by trimming the G-quadruplex DNAzyme as Cascade. The proposed method can detect 9.8 CFU (per reaction) of pure cultured V. parahaemolyticus, and the sensitivity is comparable to real-time LAMP. It has been applied for practical use and showed the capability to detect 6.1 × 102 CFU/mL V. parahaemolyticus in shrimp samples. Based on this, the newly established Cascade method can be employed as a universal biosensing strategy for pathogenic bacterial testing in the field.

Oxidase-like Fe-N/C single atom nanozyme enables sensitive detection of ascorbic acid and acid phosphatase.

The development of cost-effective and easy-to-use strategies for the detection of ascorbic acid (AA) and acid phosphatase (ACP) is in high demand but challenging. Thus, we report a novel colorimetric platform based on Fe-N/C single atom nanozyme with efficient oxidase mimicking activity for their highly sensitive detection. The designed Fe-N/C single atom nanozyme can directly oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue oxidation product (oxTMB) in the absence of H2O2. In addition, L-ascorbic acid 2-phosphate can be hydrolyzed to ascorbic acid in the presence of ACP, which inhibits the oxidation reaction and results in a significant bleaching of the blue color. Based on these phenomena, a novel colorimetric assay with high catalytic activity was developed for the determination of ascorbic acid and acid phosphatase with detection limits of 0.092 µM and 0.048 U/L, respectively. Notably, this strategy was successfully applied to the determination of ACP in human serum samples and evaluate ACP inhibitors, indicating its potential as a valuable tool for clinical diagnosis and research.