title: Multifunctional nanoparticle-protein conjugates with controllable bioactivity and pH responsiveness.
abstract: The modulation of protein activity is of significance for disease therapy, molecular diagnostics, and tissue engineering. Nanoparticles offer a new platform for the preparation of protein conjugates with improved protein properties. In the present work, Escherichia coli (E. coli) inorganic pyrophosphatase (PPase) and poly(methacrylic acid) (PMAA) were attached together to gold nanoparticles (AuNPs), forming AuNP-PPase-PMAA conjugates having controllable multi-biofunctionalities and responsiveness to pH. By treating with poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and regulating the pH, the bioactivity of the conjugate becomes "on/off"-switchable. In addition, by taking advantage of the ability of AuNPs to undergo reversible aggregation/dispersion, the conjugates can be recycled and reused multiple times; and due to the shielding effect of the PMAA, the conjugated enzyme has high resistance to protease digestion. This approach has considerable potential in areas such as controlled delivery and release of drugs, biosensing, and biocatalysis.
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Feng
authors: F
authors: Liu
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Lulu
authors: L
authors: Xue
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Yuqi
authors: Y
authors: Yuan
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Jingjing
authors: J
authors: Pan
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Chenjie
authors: C
authors: Zhang
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Hongwei
authors: H
authors: Wang
authors: School of Biomedical Engineering, Department of Chemical Engineering, McMaster University, Hamilton, Ontario, Canada.
authors: John L
authors: JL
authors: Brash
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Lin
authors: L
authors: Yuan
authors: The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China. wanghw@suda.edu.cn yuanl@suda.edu.cn.
authors: Hong
authors: H
authors: Chen
mesh_terms: D000067493:Dynamic Light Scattering; D004926:Escherichia coli / Q000201:enzymology; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D043564:Inorganic Pyrophosphatase / Q000737:chemistry* / Q000378:metabolism; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008689:Methacrylates / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D009757:Nylons / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014357:Trypsin / Q000378:metabolism
chemical_list: D008689:Methacrylates; D009757:Nylons; D011109:Polymethacrylic Acids; D013438:Sulfhydryl Compounds; C407037:poly(2-(dimethylamino)ethyl methacrylate); C030613:polymethacrylic acid; D006046:Gold; D014357:Trypsin; D043564:Inorganic Pyrophosphatase