Goharshadi E, Boghossian AA. Micropreparative Gel Electrophoresis for Purification of Nanoscale Bioconjugates

Conventional techniques for purifying macromolecular conjugates often require complex and costly installments that are inaccessible to most laboratories. In this work, we develop a one-step micropreparative method based on a trilayered polyacrylamide gel electrophoresis (MP-PAGE) setup to purify biological samples, synthetic nanoparticles, as well as biohybrid complexes. We apply this method to recover DNA from a ladder mixture with yields of up to 90%, compared to the 58% yield obtained using the conventional crush-and-soak method. MP-PAGE was also able to isolate enhanced yellow fluorescence protein (EYFP) from crude cell extract with 90% purity, which is comparable to purities achieved through a more complex two-step purification procedure involving size exclusion and immobilized metal-ion affinity chromatography. This technique was further extended to demonstrate size-dependent separation of a commercial mixture of graphene quantum dots (GQDs) into three different fractions with distinct optical properties. Finally, MP-PAGE was used to isolate DNA-EYFP and DNA-GQD bioconjugates from their reaction mixture of DNA and EYFP and GQD precursors, samples that otherwise could not be effectively purified by conventional chromatography. MP-PAGE thus offers a rapid and versatile means of purifying biological and synthetic nanomaterials without the need for specialized equipment.

An innovative ring-shaped electroeluter for high concentration preparative isolation of protein from polyacrylamide gel

A ring-shaped electroeluter (RSE) was designed for protein recovery from polyacrylamide gel matrix. The RSE was designed in such a way that a ring-shaped well was used to place gel slices and an enrichment well was used to collect eluted protein samples. With HSA as model protein, the electroelution time was less than 30 min with 80% recovery rate, and the concentration of recovered protein was 50 times higher than that of conventional method. The RSE could be reused at least ten times. The developed device makes great advance towards economic electroelution of biomolecules (such as proteins) from gel matrix.