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Comprehensive Summary: Single‐nucleotide variants (SNVs) are crucial in disease development, but their accurate detection is challenging due to their low abundance and interference from wild‐type targets. Although nucleic acid analogs like peptide nucleic acids (PNAs) have been used for SNV detection, they often lack programmable sensitivity and specificity due to poorly calculated thermodynamics and kinetics. Here, we present a computational method for calculating the stacking energy of PNA and DNA hybrids, leveraging nearest neighbor parameters. Validation against experimental data from 16 sequences under varied hybridization conditions yielded good agreement using Bland‐Altman analysis, with all data points falling within the confidence interval. Our findings indicate that PNA‐DNA hybridization is thermodynamically more stable and exhibits kinetics 140‐fold faster than DNA‐DNA hybridization for identical sequences. Utilizing this computational framework, we designed PNA toehold probes, which were screened via simulations and experiments. This combined approach facilitated the identification of highly sensitive and specific PNA toehold probes for single point mutation detection via strand displacement reaction. Our results demonstrate the successful application of PNA toehold probes for detecting point mutations with high sensitivity and specificity, achieving a selective amplification of approximately 200‐fold for variants with a variant allele frequency (VAF) of 0.5% using quantitative polymerase chain reaction. [ABSTRACT FROM AUTHOR]

DNA nanostructures, known for their programmability, ease of modification, and favourable biocompatibility, have gained widespread application in the biomedical field. Among them, Tetrahedral DNA Origami (TDOs), as a novel DNA nanostructure, possesses well‐defined structures, multiple modification sites, and large cavities, making it a promising drug carrier. However, current understanding of TDOs' interactions with biological systems, particularly with target cells and organs, remains unexplored, limiting its further applications in biomedicine. In this work, we prepared TDOs with an average particle size of 40 nm and labelled them with Cy5 fluorescent molecules. Following intravenous injection in mice, the uptake of TDOs by different types of liver and kidney cells was observed. Results indicated that TDOs accumulate in renal tubules and are metabolized by Kupffer cells, epithelial cells, and hepatocytes in the liver. Additionally, in a tumour‐bearing mouse model, TDOs passively targeted tumour tissues and exhibited excellent tumour penetration and retention after rapid metabolism in hepatocytes. Our findings provide crucial insights for the development of TDO‐based drug delivery systems. [ABSTRACT FROM AUTHOR]

Breast cancer has overtaken lung cancer as the number one cancer worldwide. Paclitaxel (PTX) is a widely used first‐line anti‐cancer drug, but it is not very effective in clinical breast cancer therapy. It has been reported that triptolide (TPL) can enhance the anticancer effect of paclitaxel, and better synergistic therapeutic effects are seen with concomitant administration of PTX and TPL. In this study, we developed pH‐responsive polymeric micelles for co‐delivery of PTX and TPL, which disassembling in acidic tumour microenvironments to target drug release and effectively kill breast cancer cells. Firstly, we synthesized amphiphilic copolymer mPEG2000‐PBAE through Michael addition reaction, confirmed by various characterizations. Polymer micelles loaded with TPL and PTX (TPL/PTX‐PMs) were prepared by the thin film dispersion method. The average particle size of TPL/PTX‐PMs was 97.29 ± 1.63 nm, with PDI of 0.237 ± 0.003 and Zeta potential of 9.57 ± 0.80 mV, LC% was 6.19 ± 0.21%, EE% was 88.67 ± 3.06%. Carrier material biocompatibility and loaded micelle cytotoxicity were assessed using the CCK‐8 method, demonstrating excellent biocompatibility. Under the same drug concentration, TPL/PTX‐PMs were the most toxic to tumour cells and had the strongest proliferation inhibitory effect. Cellular uptake assays revealed that TPL/PTX‐PMs significantly increased intracellular drug concentration and enhanced antitumor activity. Overall, pH‐responsive micellar co‐delivery of TPL and PTX is a promising approach for breast cancer therapy. [ABSTRACT FROM AUTHOR]