3D Printed Immobilized pH Gradient (IPG) Carbon Microbead Arrays for Isoelectric Focusing Pre-Fractionation of Protein

This white paper introduces a carbon microbead‑based, 3D‑printed alternative to conventional IPG strips for first‑dimension isoelectric focusing (IEF) prefractionation. Ampholyte‑blended carbon microbeads are printed into tunable arrays that act as localized immobilized pH gradient (IPG) sites, enabling pI‑directed protein prefractionation with extraction efficiencies >90% (100 µm) and >85% (40 µm) under low‑input conditions. Proof‑of‑principle data using a three‑protein model system demonstrate clean hand‑off from IEF on NanoPak‑C‑IPG arrays to second‑dimension RP‑HPLC on NanoPak‑C all‑carbon columns, highlighting the platform’s potential for emerging low‑sample and single‑cell proteomics workflows.