Conventional probeheads for solution-state NMR are constructed using manual¹ or photolithographic techniques² that incorporate RF coils, tune/match circuitry, and liquid sample holders into spatially-compact housings. These techniques are suitable for probeheads with up to a few 10s of RF coils but suffer from expensive, time consuming, and labor-intensive manufacturing practices. As an alternative, we have been exploring stereographic 3D printing that provides rapid, low-cost fabrication with minimal geometric constraints. 3D printing renders topologically-complex structures in a wide variety of NMR-compatible polymers, with print resolutions of ~10µm across build volumes exceeding one cubic meter³. Herein, we demonstrate complete, 3D-printed NMR probeheads that contain RF resonators, variable tuning/matching capacitors, and liquid NMR sample cavities. Fluidically-addressable channels and cavities are included in the probehead structure, providing a means for hydraulically-controlled RF tuning/matching and liquid NMR sample loading/unloading. Electrically conductive RF circuitry is defined within the 3D printed polymer bodies by metallizing certain structures with silver ink. In this way, multiple independent RF coils and NMR sample cavities can be fabricated into a single probehead for high-throughput NMR. The unique scalability of 3D printing supports fabricating thousands of millimeter-scale coils in a single build session, providing a manufacturing pathway towards a new generation of low-cost, high-throughput probeheads.Stereographic 3D printing utilizes liquid polymer resins that are photo-crosslinked in a layer-by-layer manner. With a 3D Systems iPro 9000XL Printer using Somos 11122 Watershed material (DSM Desotech), probeheads were formed with an in-layer resolution of 40 µm and a through-layer resolution of 150 µm. Probeheads were printed with a number of non-connecting hollow channels, defining RF circuitry, hydraulic control lines for variable capacitors, or NMR sample loading pathways. After printing, the RF circuit channels were selectively metallized by injecting PELCO Silver Paint (Ted Pella Co.) to form ≈10µm silver coatings for electrically conductive pathways. In this way, RF-resonant solenoids were constructed and tuned/matched using parallel-plate variable capacitor networks included in the probehead. These capacitors contained a partially hollowed dielectric (Figure 1), which was filled with a variable amount of Fomblin fluorocarbon oil (Solvay Solexis) or D₂O (99.9%, Sigma Aldrich). Since Fomblin and D₂O are immiscible and have dielectric constants that differ by 40-fold, a moveable liquid interface between the two was placed within the capacitor’s dielectric gap to provide hydraulic control of net capacitance. Additionally, Fomblin and D₂O are invisible to ¹H NMR and bear similar magnetic susceptibility to H₂O, thus allowing the parallel plate capacitors to be placed in the vicinity of the NMR sample for a compact RF coil footprint. Probehead sample chambers were filled with 40 µL saline (1x PBS), and ¹H FIDs were collected on a 9.4T Varian/Agilent small animal imaging system (10kHz BW, 40000 points, 1 acquisition).Probeheads were successfully printed with 0.75mm-diameter hollow channels to define RF coils, each consisting of a 5mm-diameter/5-turn solenoid and three parallel-plate capacitors for tuning/matching (Figure 2). The complete RF coil circuit occupied a 2 mL footprint, which was printed into an 8mL probehead body with fluid couplings for separate hydraulic control of the capacitors and NMR sample (Figure 3). RF bench testing showed a broad tuning range of 40 MHz as the capacitors were hydraulically varied, with Q ≈ 10 at 400 MHz (Figure 4). A match of only -12dBm (S₁₁) could be achieved at 400 MHz, and efforts are underway to optimize coil geometry and capacitor range for an improved match. However, ¹H FIDs on 40 µL saline were observed at 400 MHz (Figure 5), with a ≈ 20 Hz linewidth acceptable for high-throughput NMR processes such as drug screening. The coil gave a 1 kHz nutation rate under 125 mW input RF power, indicating compatibility with low-cost, low-power RF front-end electronics.3D printing and selective silvering was demonstrated as a new means to fabricate complete NMR probeheads for solution-state NMR. Importantly, RF coil tuning/matching and NMR sample loading/unloading could both be controlled hydraulically, which is compatible with high-throughput infrastructure from the microfluidics industry. Recently-developed 3D printers have driven the minimum build resolutions to 5-fold smaller than what was used herein, so work is now underway to fabricate single probeheads with high-density arrays of independent RF coils and NMR sample pathways. Ultimately, the metallizing process will be combined with the 3D-printing process for facile construction of large numbers of coils. Given its low cost and build scalability, 3D printing offers a unique means to construct probeheads of unprecedented complexity, enabling drastically denser arrays for high-throughput NMR and novel coil geometries that are not available with conventional fabrication techniques.