基礎講座 電気泳動(Electrophoresis)

Chemistries that Facilitate Nanotechnology Kim E. Sapsford,† W. Russ Algar, Lorenzo Berti, Kelly Boeneman Gemmill,‡ Brendan J. Casey,† Eunkeu Oh, Michael H. Stewart, and Igor L. Medintz*,‡ †Division of Biology, Department of Chemistry and Materials Science, Office of Science and Engineering Laboratories, U.S. Food and Drug Administration, Silver Spring, Maryland 20993, United States ‡Center for Bio/Molecular Science and Engineering Code 6900 and Division of Optical Sciences Code 5611, U.S. Naval Research Laboratory, Washington, D.C. 20375, United States College of Science, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, United States Department of Biochemistry and Molecular Medicine, University of California, Davis, School of Medicine, Sacramento, California 95817, United States Sotera Defense Solutions, Crofton, Maryland 21114, United States

Functionalizing nanoparticles with biological molecules: developing chemistries that facilitate nanotechnology.

Potential applications of enzymes immobilized on/in nano materials: A review

Towards lignin-based functional materials in a sustainable world

Nanomaterials are finding increasing use for biomedical applications such as imaging, diagnostics, and drug delivery. While it is well understood that nanoparticle (NP) physico-chemical properties can dictate biological responses and interactions, it has been difficult to outline a unifying framework to directly link NP properties to expected in vitro and in vivo outcomes. When introduced to complex biological media containing electrolytes, proteins, lipids, etc., nanoparticles (NPs) are subjected to a range of forces which determine their behavior in this environment. One aspect of NP behavior in biological systems that is often understated or overlooked is aggregation. NP aggregation will significantly alter in vitro behavior (dosimetry, NP uptake, cytotoxicity), as well as in vivo fate (pharmacokinetics, toxicity, biodistribution). Thus, understanding the factors driving NP colloidal stability and aggregation is paramount. Furthermore, studying biological interactions with NPs at the nanoscale level requires an interdisciplinary effort with a robust understanding of multiple characterization techniques. This review examines the factors that determine NP colloidal stability, the various efforts to stabilize NP in biological media, the methods to characterize NP colloidal stability in situ, and provides a discussion regarding NP interactions with cells.

/pdf/nanoparticle-colloidal-stability-in-cell-culture-media-and-1ndbwya20h.pdf

Nanoparticle colloidal stability in cell culture media and impact on cellular interactions

Protein repellant silicone surfaces by covalent immobilization of poly(ethylene oxide).

Immobilization of heparin on a silicone surface through a heterobifunctional PEG spacer

Sugarsilanes, alkoxysilanes derived from sugars and sugar alcohols including glycerol, sorbitol, maltose and dextran, were hydrolyzed to prepare monolithic, mesoporous silicas. Unlike conventional alkoxysilanes such as tetramethylorthosilicate (TMOS) and tetraethylorthosilicate (TEOS), the sol–gel hydrolysis and cure rates of sugarsilanes were very sensitive to ionic strength, but not to pH: comparable rates of gelation were observed for any specific compound at constant ionic strength over a pH range of about 5.5–11. Reduced levels of shrinkage when compared to TEOS (65% for diglycerylsilane (DGS)-derived silica; 50% for monosorbitylsilane (MSS)-derived silica) were also observed provided that the residual sugars were not washed or pyrolyzed from the silica monolith. Pore sizes in the dried silica monoliths (∼2–3 nm diameter) were marginally increased by the addition of non-functional polyethylene oxide (PEO)
				(mesopore sizes: no PEO, 3.1 nm; 4 wt% PEO MW 2000, 10000, 3.3 and 3.5 nm, respectively): the protein Human Serum Albumin did not act as a porogen. PEO terminated with Si(OEt)3 groups (TES-PEO), however, was very efficient at increasing mesopore size (TES-PEO MW 200 and 10000, led to pores of average diameter 3.7 and 6.1 nm, respectively). The addition of a multivalent metal such as Mg2+ to the sol increased the pore sizes of glycerol silane-derived silica, but led to decreased sizes in silica prepared from TEOS. These changes in cure chemistry and final properties are attributed to a distortion of the silica cure equilibrium by the multidentate sugar ligands.

/pdf/sugar-modified-silanes-precursors-for-silica-monoliths-7kiso7ztzl.pdf

Sugar-modified silanes: precursors for silica monoliths

The development of bioaffinity chromatography columns that are based on the entrapment of biomolecules within the pores of sol−gel-derived monolithic silica is reported. Monolithic nanoflow columns are formed by mixing the protein-compatible silica precursor diglycerylsilane with a buffered aqueous solution containing poly(ethylene oxide) (PEO, MW 10 000) and the protein of interest and then loading this mixture into a fused-silica capillary (150−250-μm i.d.). Spinodal decomposition of the PEO-doped sol into two distinct phases prior to the gelation of the silica results in a bimodal pore distribution that produces large macropores (>0.1 μm), to allow good flow of eluent with minimal back pressure, and mesopores (∼3−5-nm diameter) that retain a significant fraction of the entrapped protein. Addition of low levels of (3-aminopropyl)triethoxysilane is shown to minimize nonselective interactions of analytes with the column material, resulting in a column that is able to retain small molecules by virtue of th...

Protein-Doped Monolithic Silica Columns for Capillary Liquid Chromatography Prepared by the Sol−Gel Method: Applications to Frontal Affinity Chromatography

Firefly luciferase (FL) was entrapped in sol−gel-derived silica containing precursors based on covalent linkage of d-gluconolactone or d-maltonolactone to (aminopropyl)triethoxysilane to form N-(3-triethoxysilylpropyl)gluconamide or N-(3-triethoxysilylpropyl)maltonamide. The enzyme was active and stable in this material and showed catalytic constants close to those in solution. As little as 20 amol ATP could be detected with the entrapped FL, and the entrapped enzyme could be used over several cycles.

Yang Chen

Papers

Protein repellant silicone surfaces by covalent immobilization of poly(ethylene oxide).

Immobilization of heparin on a silicone surface through a heterobifunctional PEG spacer

Sugar-modified silanes: precursors for silica monoliths

Protein-Doped Monolithic Silica Columns for Capillary Liquid Chromatography Prepared by the Sol−Gel Method: Applications to Frontal Affinity Chromatography

Ultrasensitive ATP detection using firefly luciferase entrapped in sugar-modified sol-gel-derived silica.