DNA is a versatile biomaterial with well-defined mechanical and biochemical properties. It has been broadly adopted to synthesize tension sensors that calibrate and visualize cellular forces at the cell-matrix interface. Here we showed that DNA-based tension sensors are vulnerable to deoxyribonucleases (DNases) which cells may express on cell membrane or secret to the culture environment. These DNases can damage the sensors, lower signal-to-noise ratio or even produce false signal in cellular force imaging. To address this issue, we tested peptide nucleic acid (PNA), chemically modified RNA and their hybrids with DNA as alternative biomaterials for constructing tension sensors. Four duplexes: double-stranded DNA (dsDNA), PNA/DNA, dsRNA (modified RNA) and PNA/RNA, were tested and evaluated in terms of DNase resistance, cellular force imaging ability and material robustness. The results showed that all PNA/DNA, dsRNA and PNA/RNA exhibited strong resistance to both soluble DNase I and membrane-bound DNase on cells. However, PNA/RNA-based tension sensor had low signal-to-noise ratio in cellular force imaging, and dsRNA-based tension sensor exhibited strong non-specific signal unrelated to cellular forces. Only PNA/DNA-based tension sensor reported cellular forces with highest signal-to-noise ratio and specificity. Collectively, we confirmed that PNA/DNA hybrid is an accessible material for the synthesis of DNase-resistant tension sensor that retains the force-reporting capability and remains stable in DNase-expressing cells. This new class of tension sensors will broaden the application of tension sensors in the study of cell mechanobiology.

中文翻译：

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基于肽核酸的张力传感器，用于细胞力成像，具有很强的 DNase 抗性。


DNA 是一种多功能生物材料，具有明确的机械和生化特性。它已被广泛用于合成张力传感器，用于校准和可视化细胞-基质界面处的细胞力。在这里，我们表明基于 DNA 的张力传感器容易受到脱氧核糖核酸酶 (DNase) 的影响，脱氧核糖核酸酶可能在细胞膜上表达或分泌到培养环境中。这些 DNA 酶会损坏传感器、降低信噪比，甚至在细胞力成像中产生错误信号。为了解决这个问题，我们测试了肽核酸 (PNA)、化学修饰的 RNA 及其与 DNA 的混合物作为构建张力传感器的替代生物材料。四种双链体：双链 DNA (dsDNA)、PNA/DNA、dsRNA（修饰的 RNA）和 PNA/RNA，在 DNase 抗性、细胞力成像能力和材料稳健性方面进行了测试和评估。结果表明，所有 PNA/DNA、dsRNA 和 PNA/RNA 对细胞上可溶性 DNase I 和膜结合 DNase 均表现出较强的抵抗力。然而，基于PNA/RNA的张力传感器在细胞力成像中信噪比较低，而基于dsRNA的张力传感器表现出与细胞力无关的强非特异性信号。只有基于 PNA/DNA 的张力传感器报告了具有最高信噪比和特异性的细胞力。总的来说，我们证实 PNA/DNA 杂化物是一种用于合成 DNase 抗性张力传感器的可用材料，该传感器保留了力报告能力并在 DNase 表达细胞中保持稳定。这类新型张力传感器将拓宽张力传感器在细胞力生物学研究中的应用。