Unique physical, chemical, and optical phenomena arise when materials are confined to the nanoscale. We are accustomed to making observations for the behavior of living systems on a macroscopic scale that is intuitive for the time and size scales of our day-to-day lives. However, the building blocks of life: proteins, nucleic acids, and cells, occupy different spatiotemporal scales. Our lab focuses on understanding and exploiting tunable optical and mechanical properties of nanomaterials to access information about biological systems stored at the nano-scale. In the context of leveraging nanomaterial optical properties, we present recent work on developing and implementing neuromodulator nanosensors to image serotonin or dopamine volume transmission in the extracellular space of the brain. We validate our dopamine nanosensor in acute striatal slices with electrical and optogenetic stimulation of dopamine release, and show disrupted dopamine release or reuptake kinetics when brain tissue is exposed to dopamine agonist or antagonist drugs. In the context of leveraging nanomaterial chemical properties, we also discuss how high aspect ratio nanomaterials can be synthesized to carry biomolecular cargo to living systems. In particular, genetic engineering of plants is at the core of environmental sustainability efforts, but the physical barrier presented by the cell wall has limited the ease and throughput with which exogenous biomolecules can be delivered to plants. We will describe how nanomaterials engineering principles can be leveraged to genetically manipulate living plants, without transgene integration, in efforts to reconcile the benefits of crop genetic engineering with the demand for non-GMO foods. Our work in the agricultural space provides a promising tool for species-independent, targeted, and passive delivery of genetic material, without transgene integration, into plant cells for rapid and parallelizable testing of plant genotype-phenotype relationships.