Enhanced Protein Adsorption and Facilitated Refolding
of Like-Charged Protein with Highly Charged Silica Nanoparticles Fabricated
by Sequential Double Modifications
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Abstract
Silica nanoparticles (SNPs) were
sequentially modified with poly(ethylenimine)
(PEI) and 2-diethylaminoethyl chloride (DEAE) to prepare a series
of positively charged SNPs-PEI and SNPs-PEI-DEAE. The sequential double-modification
strategy produced a charge density as high as 1740 μmol/g (4524
μmol/mL), which offered a very high adsorption capacity for
bovine serum albumin (314 mg/g). Most importantly, the highly charged
SNPs-PEI and SNPs-PEI-DEAE could efficiently facilitate the refolding
of like-charged protein at extremely low utilization. For instance,
in the refolding of 1 mg/mL lysozyme, the refolding yield reached
75% with only 3.3 μL/mL SNPs-PEI-DEAE. The bead consumption
was reduced by nearly 96% as compared to that of the charged microspheres
used previously to reach a similar yield. The results proved that
the polyelectrolyte-modified SNPs were promising for applications
in facilitating like-charged protein refolding, and the research opened
up a new way for biotechnology applications of highly charged nanoparticles