Some proteins secreted by microorganisms have large molecular weights. We report here an approach to prepare coating by multilayer polymers for antifouling of proteins, especially the proteins with a large molecular w...Some proteins secreted by microorganisms have large molecular weights. We report here an approach to prepare coating by multilayer polymers for antifouling of proteins, especially the proteins with a large molecular weight.Stainless steel was used as the model substrate. The substrate was first coated with a hybrid polymer film, which was formed by simultaneous hydrolytic polycondensation of 3-aminopropyltriethoxysilane and polymerization of dopamine(HPAPD). After grafting the macroinitiator 2-bromoisobutyryl bromide, the block polymer brushes PMMA-b-PHEMA were grafted. Three proteins were used to test protein adsorption and antifouling behavior of the coating, including recombinant green fluorescent(54 k Da), recombinant R-transaminase(2 × 90 k Da), and recombinant catalase(4 × 98 k Da). It is demonstrated that the block polymer brushes not only can prevent the adsorption of small molecular weight proteins, but also can significantly reduce the adsorption of the large molecular weight proteins.展开更多
A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described（PLCs）. Two types of PLCs of propyl hydroxypropyl cellulose ester（PPC） and octyl hydroxypropyl cellulos...A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described（PLCs）. Two types of PLCs of propyl hydroxypropyl cellulose ester（PPC） and octyl hydroxypropyl cellulose ester（OPC） were prepared by esterification from hydroxypropyl cellulose, and then were mixed with polyvinyl chloride and polyurethane to obtain composite films by solution casting, respectively. The surface morphology of PLCs and their composite films were characterized by polarized optical microscopy（POM） and scanning electron microscopy（SEM）, suggesting the existence of microdomain separation with fingerprint texture in PLC composite films. Water contact angle measurement results indicated that hydrophilicity of PLC/polymer composite films was dependent on the type and content of PLC as well as the type of matrix due to their interaction. Using bovine serum albumin（BSA） as a model protein, protein adsorption results revealed that PLCs with protein-resistant property can obviously suppress protein adsorption on their composite films, probably due to their flexible LC state. Moreover, all PLCs and their composites exhibited non-toxicity by MTT assay, suggesting their safety for biomedical applications.展开更多
Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnosti...Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnostic tools,and medical products.Increasingly,novel polymer materials with greater chemical intricacy and reduced dimensionality are used for various applications involving adsorbed proteins on their surfaces.Hence,the nature of protein-surface interactions to consider is becoming much more complicated than before.A large body of literature exists for protein adsorption.However,most of these investigations have focused on collectively measured,ensemble-averaged protein behaviors that occur on macroscale and chemically unvarying polymer surfaces instead of direct measurements at the single protein or sub-protein level.In addition,interrogations of protein-polymer adsorption boundaries in these studies were typically carried out by indirect methods,whose insights may not be suitably applied for explaining individual protein adsorption processes occurring onto nanostructured,chemically varying polymer surfaces.Therefore,an important gap in our knowledge still exists that needs to be systematically addressed via direct measurement means at the single protein and sub-protein level.Such efforts will require multifaceted experimental and theoretical approaches that can probe multilength scales of protein adsorption,while encompassing both single proteins and their collective ensemble behaviors at the length scale spanning from the nanoscopic all the way to the macroscopic scale.In this review,key research achievements in nanoscale protein adsorption to date will be summarized.Specifically,protein adsorption studies involving polymer surfaces with their defining feature dimensions and associated chemical partitions comparable to the size of individual proteins will be discussed in detail.In this regard,recent works bridging the crucial knowledge gap in protein adsorption will be highlighted.New findings of intriguing protein surface assembly behaviors and adsorption kinetics unique to nanoscale polymer templates will be covered.Single protein and sub-protein level approaches to reveal unique nanoscale protein-polymer surface interactions and protein surface assembly characteristics will be also emphasized.Potential advantages of these research endeavors in laying out fundamentally guided design principles for practical product development will then be discussed.Lastly,important research areas still needed to further narrow the knowledge gap in nanoscale protein adsorption will be identified.展开更多
In recent years there has been an increasing interest in the use of autohydrogenotrophic bacteria to treat nitrate from wastewater. However, our knowledge about the characteristics of extracellular polymeric substance...In recent years there has been an increasing interest in the use of autohydrogenotrophic bacteria to treat nitrate from wastewater. However, our knowledge about the characteristics of extracellular polymeric substances（EPS） releasing by these activities is not yet very advanced. This study aimed to investigate the change in EPS compositions under various p H values and hydrogen flow rates, taking into consideration nitrogen removal. Results showed that p H 7.5 and a hydrogen flow rate of 90 m L/min were the optimal operating conditions, resulting in 100% nitrogen removal after 6 hr of operation. Soluble and bound polysaccharides decreased, while bound proteins increased with increasing p H. Polysaccharides increased with increasing hydrogen flow rate. No significant change of bound proteins was observed at various hydrogen flow rates.展开更多
基金Supported by the National Natural Science Foundation of China(21476023)
文摘Some proteins secreted by microorganisms have large molecular weights. We report here an approach to prepare coating by multilayer polymers for antifouling of proteins, especially the proteins with a large molecular weight.Stainless steel was used as the model substrate. The substrate was first coated with a hybrid polymer film, which was formed by simultaneous hydrolytic polycondensation of 3-aminopropyltriethoxysilane and polymerization of dopamine(HPAPD). After grafting the macroinitiator 2-bromoisobutyryl bromide, the block polymer brushes PMMA-b-PHEMA were grafted. Three proteins were used to test protein adsorption and antifouling behavior of the coating, including recombinant green fluorescent(54 k Da), recombinant R-transaminase(2 × 90 k Da), and recombinant catalase(4 × 98 k Da). It is demonstrated that the block polymer brushes not only can prevent the adsorption of small molecular weight proteins, but also can significantly reduce the adsorption of the large molecular weight proteins.
基金Funded by the National Natural Science Foundation of China(Nos.31170911 and 31040027)the Research Development and Innovation Fund of Jinan University(No.21611410)+1 种基金the Open Fund of the First Affiliated Hospital,Jinan University,Guangzhou(No.511005024)the Macao Science and Technology Development Fund(No.064/2013/A2)
文摘A novel biomimetic protein-resistant modifier based on cellulose-based polymeric liquid crystals was described（PLCs）. Two types of PLCs of propyl hydroxypropyl cellulose ester（PPC） and octyl hydroxypropyl cellulose ester（OPC） were prepared by esterification from hydroxypropyl cellulose, and then were mixed with polyvinyl chloride and polyurethane to obtain composite films by solution casting, respectively. The surface morphology of PLCs and their composite films were characterized by polarized optical microscopy（POM） and scanning electron microscopy（SEM）, suggesting the existence of microdomain separation with fingerprint texture in PLC composite films. Water contact angle measurement results indicated that hydrophilicity of PLC/polymer composite films was dependent on the type and content of PLC as well as the type of matrix due to their interaction. Using bovine serum albumin（BSA） as a model protein, protein adsorption results revealed that PLCs with protein-resistant property can obviously suppress protein adsorption on their composite films, probably due to their flexible LC state. Moreover, all PLCs and their composites exhibited non-toxicity by MTT assay, suggesting their safety for biomedical applications.
基金D.H.C.,T.X,and J.T.acknowledge financial support on this work by the National Science Foundation(NSF Award Nos.CHE1404658,CHE1903857)from the Macromolecular,Supramolecular and Nanochemistry Program under the Division of Chemistry.J.H.acknowledges the NSF support from the Independent Research/Development(IR/D)program while serving at the National Science Foundation.
文摘Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnostic tools,and medical products.Increasingly,novel polymer materials with greater chemical intricacy and reduced dimensionality are used for various applications involving adsorbed proteins on their surfaces.Hence,the nature of protein-surface interactions to consider is becoming much more complicated than before.A large body of literature exists for protein adsorption.However,most of these investigations have focused on collectively measured,ensemble-averaged protein behaviors that occur on macroscale and chemically unvarying polymer surfaces instead of direct measurements at the single protein or sub-protein level.In addition,interrogations of protein-polymer adsorption boundaries in these studies were typically carried out by indirect methods,whose insights may not be suitably applied for explaining individual protein adsorption processes occurring onto nanostructured,chemically varying polymer surfaces.Therefore,an important gap in our knowledge still exists that needs to be systematically addressed via direct measurement means at the single protein and sub-protein level.Such efforts will require multifaceted experimental and theoretical approaches that can probe multilength scales of protein adsorption,while encompassing both single proteins and their collective ensemble behaviors at the length scale spanning from the nanoscopic all the way to the macroscopic scale.In this review,key research achievements in nanoscale protein adsorption to date will be summarized.Specifically,protein adsorption studies involving polymer surfaces with their defining feature dimensions and associated chemical partitions comparable to the size of individual proteins will be discussed in detail.In this regard,recent works bridging the crucial knowledge gap in protein adsorption will be highlighted.New findings of intriguing protein surface assembly behaviors and adsorption kinetics unique to nanoscale polymer templates will be covered.Single protein and sub-protein level approaches to reveal unique nanoscale protein-polymer surface interactions and protein surface assembly characteristics will be also emphasized.Potential advantages of these research endeavors in laying out fundamentally guided design principles for practical product development will then be discussed.Lastly,important research areas still needed to further narrow the knowledge gap in nanoscale protein adsorption will be identified.
基金financial support from the Ministry of Science and Technology of the Republic of China(No.102-2221-E-009-010-MY3)
文摘In recent years there has been an increasing interest in the use of autohydrogenotrophic bacteria to treat nitrate from wastewater. However, our knowledge about the characteristics of extracellular polymeric substances（EPS） releasing by these activities is not yet very advanced. This study aimed to investigate the change in EPS compositions under various p H values and hydrogen flow rates, taking into consideration nitrogen removal. Results showed that p H 7.5 and a hydrogen flow rate of 90 m L/min were the optimal operating conditions, resulting in 100% nitrogen removal after 6 hr of operation. Soluble and bound polysaccharides decreased, while bound proteins increased with increasing p H. Polysaccharides increased with increasing hydrogen flow rate. No significant change of bound proteins was observed at various hydrogen flow rates.
