TY - JOUR
T1 - Localized entrapment of green fluorescent protein within nanostructured polymer films
AU - Kozlovskaya, Veronika
AU - Ankner, John F.
AU - O'Neill, Hugh
AU - Zhang, Qiu
AU - Kharlampieva, Eugenia
PY - 2011/12/21
Y1 - 2011/12/21
N2 - Protein entrapment within ultrathin polymer matrices is of significant interest for applications in biosensing, drug delivery, and bioconversion; however, it remains a big challenge due to insufficient control over protein distribution inside the matrices. We report on nanostructured protein-polyelectrolyte (PE) films obtained through localized incorporation of green fluorescent protein (GFP) within poly(styrene sulfonate)/poly(allylamine hydrochloride) matrices assembled via the spin-assisted layer-by-layer method. Film compositional and structural analyses were performed by using a combination of techniques such as neutron and X-ray reflectometry, circular dichroism (CD), atomic force microscopy (AFM), spectroscopic ellipsometry, and Attenuated Total Reflection Fourier transform infrared spectroscopy (ATR-FTIR). By using deuterated GFP as a marker for neutron scattering contrast we have inferred the architecture of the films both in vertical and lateral directions. We found that films assembled with a single GFP layer confined at various distances from the substrate exhibit a strong localization of the GFP layer without intermixing into the PE matrix. The GFP volume fraction approached the maximum value of a monolayer packing density of randomly oriented GFP molecules. However, partial intermixing of the GFP with polymeric material is evidenced in multiple-GFP layer films which showed alternating protein-rich and protein-deficient regions. Our results yield new insights into the organization of immobilized proteins within polyelectrolyte matrices and open opportunities for fabrication of protein-containing films with well-organized structure and controllable function, a crucial requirement for advanced sensing applications.
AB - Protein entrapment within ultrathin polymer matrices is of significant interest for applications in biosensing, drug delivery, and bioconversion; however, it remains a big challenge due to insufficient control over protein distribution inside the matrices. We report on nanostructured protein-polyelectrolyte (PE) films obtained through localized incorporation of green fluorescent protein (GFP) within poly(styrene sulfonate)/poly(allylamine hydrochloride) matrices assembled via the spin-assisted layer-by-layer method. Film compositional and structural analyses were performed by using a combination of techniques such as neutron and X-ray reflectometry, circular dichroism (CD), atomic force microscopy (AFM), spectroscopic ellipsometry, and Attenuated Total Reflection Fourier transform infrared spectroscopy (ATR-FTIR). By using deuterated GFP as a marker for neutron scattering contrast we have inferred the architecture of the films both in vertical and lateral directions. We found that films assembled with a single GFP layer confined at various distances from the substrate exhibit a strong localization of the GFP layer without intermixing into the PE matrix. The GFP volume fraction approached the maximum value of a monolayer packing density of randomly oriented GFP molecules. However, partial intermixing of the GFP with polymeric material is evidenced in multiple-GFP layer films which showed alternating protein-rich and protein-deficient regions. Our results yield new insights into the organization of immobilized proteins within polyelectrolyte matrices and open opportunities for fabrication of protein-containing films with well-organized structure and controllable function, a crucial requirement for advanced sensing applications.
UR - http://www.scopus.com/inward/record.url?scp=82355191827&partnerID=8YFLogxK
U2 - 10.1039/c1sm06710a
DO - 10.1039/c1sm06710a
M3 - Article
AN - SCOPUS:82355191827
SN - 1744-683X
VL - 7
SP - 11453
EP - 11463
JO - Soft Matter
JF - Soft Matter
IS - 24
ER -