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While recent advances in cryo-EM, coupled with single particle analysis, have the potential to allow structure determination in a near-native state from vanishingly few individual particles, this vision has yet to be realised in practise. Requirements for particle numbers that currently far exceed the theoretical lower limits, challenges with the practicalities of achieving high concentrations for difficult-to-produce samples, and inadequate sample-dependent imaging conditions, all result in significant bottlenecks preventing routine structure determination using cryo-EM. Therefore, considerable efforts are being made to circumvent these bottlenecks by developing affinity purification of samples on-grid; at once obviating the need to produce large amounts of protein, as well as more directly controlling the variable, and sample-dependent, process of grid preparation. In this proof-of-concept study, we demonstrate a further practical step towards this paradigm, developing a 3D-printable flow-cell device to allow on-grid affinity purification from raw inputs such as whole cell lysates, using graphene oxide-based affinity grids. Our flow-cell device can be interfaced directly with routinely-used laboratory equipment such as liquid chromatographs, or peristaltic pumps, fitted with standard chromatographic (1/16”) connectors, and can be used to allow binding of samples to affinity grids in a controlled environment prior to the extensive washing required to remove impurities. Furthermore, by designing a device which can be 3D printed and coupled to routinely used laboratory equipment, we hope to increase the accessibility of the techniques presented herein to researchers working towards single-particle macromolecular structures.

Instructional television (ITV) has been little used in the nation's schools because ITV hardware and software has been unreliable and expensive and teachers have yet to learn to use ITV. The perfection of inexpensive videotape recorders/players (VTR) and inexpensive tapes and cameras could remedy the problem. A package consisting of 10 mobile VTR's and television sets, a tape library, and several TV cameras per school of 50 rooms and proportionate equipment for schools of other sizes would cost only about $5 per student per year. If an active head-end at each school transmits the ITV programs by cable to the classroom it would cost about $33 per student per year. The cost of school ITV could be lowered by a dedicated school district cable system--a 40 channel cable to each school and thence to each classroom. The Federal Communications Commission sponsored 4-channel fixed service would provide less flexibility and would be slightly more costly for approximately equal service to classrooms. Although satellite distribution has been proposed for ITV in the United States, a lack of knowledge of the cost of satellites and satellite reception equipment makes it difficult to reliably estimate costs. Satellite distribution, however, should become increasingly possible in the future. (JY)