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In vitro gliding assay is a well-established assay for determining the activity of protein motors, such as actin-associated myosins and microtubule-associated kinesins and dyneins. In one of the conventional methods, protein motors are immobilized onto a nitrocellulose-coated coverslip and it propels actin filaments in the presence of ATP. Gliding assays also serve as the foundation for protein-motor-based nanotechnological devices such as biosensing and sorting. However, the preparation of nitrocellulose-coated coverslips is time-consuming and produces rough surfaces. Furthermore, the nitrocellulose film exhibits high background autofluorescence, which can be a problem in single-molecule measurements. Here, we investigated the use of hexamethyldisilazane (HMDS) to study actomyosin function and characterized its physical properties on glass coverslips and glass capillary tubes. We showed that the total preparation time to coat a coverslip with HMDS is 12-hour protocol for coating glass surfaces with nitrocellulose. In contrast to nitrocellulose film, HMDS vapor deposition is effortless and provides an atomically flat surface with low autofluorescence. In addition, HMDS does not interfere with myosin function, which is indicated by the similar actin gliding speed when compared with nitrocellulose. Our results show that HMDS vapor deposition is a more favorable surface treatment to nitrocellulose for in vitro gliding assay.

In vitro gliding assay is a well-established assay for determining the activity of protein motors, such as actin-associated myosins and microtubule-associated kinesins and dyneins. In one of the conventional methods, protein motors are immobilized onto a nitrocellulose-coated coverslip and it propels actin filaments in the presence of ATP. Gliding assays also serve as the foundation for protein-motor-based nanotechnological devices such as biosensing and sorting. However, the preparation of nitrocellulose-coated coverslips is time-consuming and produces rough surfaces. Furthermore, the nitrocellulose film exhibits high background autofluorescence, which can be a problem in single-molecule measurements. Here, we investigated the use of hexamethyldisilazane (HMDS) to study actomyosin function and characterized its physical properties on glass coverslips and glass capillary tubes. We showed that the total preparation time to coat a coverslip with HMDS is 12-hour protocol for coating glass surfaces with nitrocellulose. In contrast to nitrocellulose film, HMDS vapor deposition is effortless and provides an atomically flat surface with low autofluorescence. In addition, HMDS does not interfere with myosin function, which is indicated by the similar actin gliding speed when compared with nitrocellulose. Our results show that HMDS vapor deposition is a more favorable surface treatment to nitrocellulose for in vitro gliding assay.

Biological materials are self-assembled with near-atomic precision in living cells, whereas synthetic 3D structures generally lack such precision and controllability. Recently, DNA nanotechnology, especially DNA origami technology, has been useful in the bottom-up fabrication of well-defined nanostructures ranging from tens of nanometres to sub-micrometres. In this Primer, we summarize the methodologies of DNA origami technology, including origami design, synthesis, functionalization and characterization. We highlight applications of origami structures in nanofabrication, nanophotonics and nanoelectronics, catalysis, computation, molecular machines, bioimaging, drug delivery and biophysics. We identify challenges for the field, including size limits, stability issues and the scale of production, and discuss their possible solutions. We further provide an outlook on next-generation DNA origami techniques that will allow in vivo synthesis and multiscale manufacturing.