Mechanically Interfacing with Biology via Piezoelectric Nanowires

总的来说，细胞可以执行令人难以置信的复杂任务。它们的功能使我们能够与世界互动，抗击疾病，修复构成我们的材料。控制这种行为的能力可能会在再生医学、组织工程和生物模拟材料等领域带来重大进展。然而，直接与细胞接触以决定它们的行为远非微不足道。通常调节细胞功能的化学途径和机制经过数百万年的进化已经被设计出来，导致了极其复杂和精细平衡的系统。对这些计划的干预很少会成功。有趣的是，一个被称为机械生物学的新兴研究领域可能会为这个问题提供一个解决方案。这描述了细胞系统对其机械环境特别敏感的现象，即细胞的功能和行为可以由其周围环境的物理属性和它们所经历的力来调节。例如，生长在软基质上的人类干细胞很可能分化为脂肪细胞，而在硬质基质上生长同样的干细胞将导致骨细胞的形成。然后，控制细胞功能的挑战转移到控制细胞环境的机械性能的挑战上。在这种情况下，压电材料是机械生物学工具的理想候选者，因为它们能够检测和施加微小的力。通过将压电材料与类似于手机触摸屏上的电极栅格相结合，可以创造出一种用于电池的触摸屏。在这种装置上生长的电池会对压电材料施加压力，使其产生一些电荷。然后，可以使用电极栅格以一定程度的空间分辨率来检测这种电荷。此外，通过相同的电极栅格，可以激励压电界面材料的各个区域，以向平台的特定部分提供局部机械刺激。通过这种方式，可以创建一个有效的生物-机电接口，以电检测并对细胞施加与生理相关的机械力，以操纵其功能。满足压电元件的材料选择标准是具有挑战性的，因为所需要的是与细胞相互作用的小型、柔性和生物兼容的压电结构。纳米结构的压电聚合物材料非常适合这一目的，因为电池本身通常是微米大小的，施加的力在微微到纳米牛顿的范围内。因此，该建议旨在开发合适的生物相容的压电聚合物纳米线作为生物-机电接口材料，从而开发出一种强大的合成生物学工具。该提案的独特目的是开展涉及尖端材料科学和工程应用的跨学科研究，以开发新的令人兴奋的生物科学研究工具。

Collectively, cells can perform incredibly complex tasks. Their function allows us to interact with the world, fight disease and repair the materials that make us. The ability to control this behaviour could lead to significant advances in areas such as regenerative medicine, tissue engineering and bio-mimetic materials. However, interfacing directly with cells to dictate their behaviour is far from trivial. The chemical pathways and mechanisms that typically regulate cell function have been devised over millions of years of evolution, resulting in fiercely complex and finely balanced systems. Interfering with these schemes rarely succeeds. Interestingly, a new and emerging field of research known as mechanobiology may offer a solution to this problem. This describes the phenomenon whereby cellular systems are exceptionally sensitive to their mechanical environment, i.e., the function and behaviour of cells can be regulated by the physical properties of their surroundings and the forces that they experience. As an example, human stem cells grown on a soft substrate are likely to differentiate into fat cells, while growing those same stem cells on a rigid substrate will lead to the formation of bone cells. The challenge of controlling cell function is then shifted to the challenge of controlling the mechanical properties of cell surroundings. In this context, piezoelectric materials are ideal candidates for tools within mechanobiology, given their ability to both detect and apply small forces. By combining piezoelectric materials with a grid of electrodes, similar to that found on the touch screen of a phone, a 'touch screen for cells' can be created. Cells growing on this device will exert a force on the piezoelectric material, causing it to develop some electric charge. This charge can then be detected with some degree of spatial resolution using the grid of electrodes. Furthermore, via the same grid of electrodes, individual areas of the piezoelectric interface material can be excited to provide local mechanical stimulation to a specific part of the platform. In this way, an effective bio-electromechanical interface can be created to both electrically detect and apply physiologically relevant mechanical forces on cells to manipulate their functionality. Meeting the materials selection criteria for the piezoelectric element is challenging, as what is required is a small, flexible and biocompatible piezoelectric structure to interact with cells. Nanostructured piezoelectric polymeric materials are ideally suited for this purpose as cells are themselves typically micron sized and exert forces in the pico- to nanonewton range. The proposal therefore aims to develop appropriate biocompatible piezoelectric polymer nanowires as the bio-electromechanical interface material, thus leading to the development of a powerful tool for synthetic biology. The proposal uniquely aims to undertake inter-disciplinary research involving the application of cutting-edge materials science and engineering to develop new and exciting tools for bioscience research.