Trace quantities of metal cations, inorganic anions, organic compounds and biomolecules can be measured using electrochemical stripping analysis (ESA). This Primer describes the principles of ESA, including methods of performing the pre-concentration and stripping steps, instrumentation and technique optimization.

Serial femtosecond crystallography is a high-throughput, serial crystallography technique for studying macromolecular crystals at an X-ray free-electron laser. This Primer gives an overview of microcrystallization methods, sample delivery and data analysis for applications including membrane proteins, radiation damage-prone systems and time-resolved experiments.

Van der Waals epitaxy provides numerous opportunities for materials integration in heterostructures. This Primer provides an overview of methodologies for producing van der Waals heterostructures, focusing on top-down assembly and bottom-up synthesis, and discusses future opportunities for their continued development.

Optogenetic techniques involve the introduction of photoreceptors into selected cells to allow control over their activity using light. In this Primer, Emiliani et al. discuss the most commonly used optogenetic tools, illumination approaches and applications in medicine, cardiovascular science and plants, among many other uses.

The physical properties of a solid-state material depends on its electronic structure, which can be studied using angle-resolved photoemission spectroscopy (ARPES). This Primer introduces the ARPES technique and describes how different variants can be used for applications including superconductors, topological materials and two-dimensional materials.

Volume electron microscopy techniques are high-resolution imaging approaches that reveal the 3D structure of cells, tissues and small model organisms at nanometre resolution. This Primer introduces the different imaging modalities, specialized sample processing and key applications in biosciences.