School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
ACS Appl Mater Interfaces. 2023 Sep 13;15(36):42196-42208. doi: 10.1021/acsami.3c07028. Epub 2023 Aug 31.
Bioactuators made of cultured skeletal muscle cells are generally driven by electrical or visible light stimuli. Among these, the technology to control skeletal muscle consisting of myoblasts genetically engineered to express photoreceptor proteins with visible light is very promising, as there is no risk of cell contamination by electrodes, and the skeletal muscle bioactuator can be operated remotely. However, due to the low biopermeability of visible light, it can only be applied to thin skeletal muscle films, making it difficult to realize high-power bioactuators consisting of thick skeletal muscle. To solve this problem, it is desirable to realize thick skeletal muscle bioactuators that can be driven by near-infrared (NIR) light, to which living tissue is highly permeable. In this study, as a promising first step, upconversion nanoparticles (UCNPs) capable of converting NIR light into blue light were bound to C2C12 myoblasts expressing the photoreceptor protein channelrhodopsin-2 (ChR2), and the myoblasts calcium ion (Ca) influx was remotely manipulated by NIR light exposure. UCNP-bound myoblasts and UCNP-bound differentiated myotubes were exposed to NIR light, and the intracellular Ca concentrations were measured and compared to myoblasts exposed to blue light. Exposure of the UCNP-bound cells to NIR light was found to be more efficient than exposure to blue light in terms of stimulating Ca influx.
由培养的骨骼肌细胞制成的生物致动器通常由电或可见光刺激驱动。在这些技术中，控制由表达光受体蛋白的成肌细胞组成的骨骼肌的技术具有很大的前景，因为不存在电极污染细胞的风险，并且骨骼肌生物致动器可以远程操作。然而，由于可见光的生物通透性低，它只能应用于薄的骨骼肌薄膜，因此难以实现由厚的骨骼肌组成的大功率生物致动器。为了解决这个问题，理想的情况是实现可以由近红外（NIR）光驱动的厚骨骼肌生物致动器，因为近红外光对活组织具有很高的通透性。在这项研究中，作为有前途的第一步，将能够将近红外光转换为蓝光的上转换纳米粒子（UCNP）与表达光受体蛋白通道视紫红质-2（ChR2）的 C2C12 成肌细胞结合，并且通过近红外光照射远程操纵成肌细胞钙离子（Ca）内流。将 UCNP 结合的成肌细胞和 UCNP 结合的分化肌管暴露于近红外光，并测量细胞内 Ca 浓度并与暴露于蓝光的成肌细胞进行比较。结果发现，与暴露于蓝光相比，UCNP 结合细胞暴露于近红外光更能有效地刺激 Ca 内流。
