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1.
Soft Matter ; 19(21): 3925-3932, 2023 May 31.
Article in English | MEDLINE | ID: mdl-37200086

ABSTRACT

Stretchable ionic conductive elastomers have been extensively studied due to their great application potential in the fields of sensors, batteries, capacitors and flexible robots. However, it is still challenging to prepare multifunctional ionic conductive elastomers with high mechanical strength and excellent tensile properties by a green and efficient method. In this study, we prepared PDES-DMA ionic conductive elastomers by a "one step" rapid in situ polymerization of AA/ChCl-type polymerizable deep eutectic solvents (PDES) and N,N-dimethylacrylamide (DMA) under ultraviolet (UV) irradiation. In addition to the characteristics of high mechanical strength (tensile strength of 9.27 MPa) and excellent tensile properties (elongation at break of 1071%), the PDES-DMA elastomer also has high transparency (>80%), strong self-adhesion (adhesion strength with glass surface 133.8 kPa) and self-healing properties. In addition, sensors based on the ionic conductive elastomer can be used to detect human movements such as finger, wrist, elbow, ankle and knee bending. Considering the convenience of the preparation method and the excellent versatility of the prepared PDES-DMA ionic conductive elastomer, we believe that the method proposed in this study has potential application prospects in the field of flexible electronics.

2.
Soft Matter ; 19(48): 9460-9469, 2023 Dec 13.
Article in English | MEDLINE | ID: mdl-38018427

ABSTRACT

Strain/pressure sensors with high sensitivity and a wide operation range have broad application prospects in wearable medical equipment, human-computer interactions, electronic skin, and so on. In this work, based on the different solubilities of Zr4+ in the aqueous phase and the hydrophobic ionic liquid [BMIM][Tf2N], we used N,N-dimethylacrylamide (DMA) as a vinyl monomer to prepare a Janus-type ionic conductive gel with one-sided adhesion through "one-step" UV irradiation polymerization. The Janus-type gel has satisfactory mechanical properties (tensile strength: 217.06 kPa, elongation at break: 1121.01%), electrical conductivity (conductivity: 0.10 S m-1), one-sided adhesion (adhesion strength to glass: 72.35 kPa) and antibacterial properties. The sensor based on the Janus gel can be used not only for real-time monitoring of strain changes caused by various movements of the human body (such as finger bending, muscle contraction, smiling, and swallowing) but also for real-time monitoring of pressure changes (such as pressing, water droplets, and writing movements). Therefore, based on the simplicity of this method for constructing Janus-type ionic conductive gels and the excellent electromechanical properties of the prepared gel, we believe that the method provided in this study has broad application prospects in the field of multifunctional wearable sensors.

3.
Soft Matter ; 18(32): 6115-6123, 2022 Aug 17.
Article in English | MEDLINE | ID: mdl-35943040

ABSTRACT

Flexible strain sensors have been extensively studied for their potential value in monitoring human activity and health. However, it is still challenging to develop multifunctional flexible strain sensors with simultaneously high transparency, strong self-adhesion, fast self-healing and excellent tensile properties. In this study, we used N,N-dimethylacrylamide (DMA) in the imidazolium-based ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([BMIM][Tf2N]) for "one-step" UV irradiation. A poly(N,N-dimethyl)acrylamide (PDMA) ion-conductive gel was prepared by site polymerization. Based on the good compatibility between PDMA and ionic liquid, the prepared ion-conductive gel has good transparency (∼90%), excellent stretchability (1080%), strong self-adhesion (67.57 kPa), fast self-healing (2 s at room temperature) and great antibacterial activity (∼99% bacterial killing efficiency). Moreover, the strain sensor based on the PDMA ion-conductive gel has good electromechanical performance and can detect different human motions. Based on the simple and easy-to-operate preparation method and the endowed multifunctionality of the PDMA ion-conductive gel, it has broad application prospects in the field of flexible electronic devices.


Subject(s)
Acrylamide , Ionic Liquids , Electric Conductivity , Humans , Hydrogels , Motion
4.
Macromol Rapid Commun ; 43(20): e2200376, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35726483

ABSTRACT

The dual-initiator technique allows the polymerization of different monomers from orthogonal polymerization mechanisms to obtain block copolymers (BCPs). In this study, it is attempted to combine photoiniferter living free radical polymerization and organocatalytic ring-opening polymerization (ROP) to design a hydroxyl-functionalized carbamodithioate, i.e., 4-(hydroxymethyl)benzyl diethylcarbamodithioate (HBDC), which can integrate photoiniferter polymerization of acrylamide monomers and ROP of cyclic carbonates. As a proof of concept, the monomer applicability is further extended to acrylates and lactones. The results confirm that the two polymerization systems are experimentally compatible in a stepwise sequence as well as in a simultaneous one-pot process to synthesize BCPs. It is reasonable to assume that HBDC can allow for simple and efficient one-pot access to well-defined BCPs from a larger range of monomers, which is more advantageous from the operational, economical, and environmental points of view.


Subject(s)
Carbonates , Polymers , Polymerization , Lactones , Free Radicals , Catalysis , Acrylates , Acrylamides
5.
Macromol Rapid Commun ; 43(8): e2100920, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35138013

ABSTRACT

A photocontrolled reversible addition-fragmentation chain transfer (RAFT) process is developed by initiating polymerization through a 1,3-diaminopropane-triethylborane (DAPTB)-diphenyl iodonium salt (Ph2 I+ ) complex (DAPTB/Ph2 I+ ) under ambient temperature and atmospheric conditions. Upon demand, this air-stable DAPTB/Ph2 I+ complex is photolyzed to liberate a reactive triethylborane that consumes atmospheric oxygen and generates ethyl radicals, which initiate and mediate RAFT polymerization. Controlled RAFT polymerization is thus achieved without any prior deoxygenation using a novel RAFT chain transfer agent, BP-FSBC, which contains both benzophenone and sulfonyl fluoride moieties. Furthermore, the kinetics of polymerization reveal that the reaction process is rapid, and well-defined polymers are produced by a 61% conversion of 2-hydroxyethyl acrylate (HEA) within 7 min and 77% conversion of N,N-dimethylacrylamide (DMA) within 10.5 min. The temporal and spatial control of this photopolymerization is also demonstrated by an "on/off" switch of UV irradiation and a painting-on-a-surface approach, respectively. In addition, active chain ends are demonstrated by preparing block copolymers by chain extension and click sulfur(VI)-fluoride exchange postreaction using RAFT-derived macrochain transfer agents.


Subject(s)
Polymers , Sulfur , Oxygen , Polymerization
6.
Macromol Rapid Commun ; 41(8): e1900430, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32134540

ABSTRACT

This review focuses on the attachment of polymer brushes to polymeric biomaterial substrates by chemical surface modification methods for biomedical applications. In the first part of this paper, a general introduction to the synthesis of polymer brushes is given. Thereafter, a comprehensive overview of recent work on the chemical surface modification of polymeric biomaterials, with a focus on "grafting-to," "grafting-from," and "grafting-through" strategies, is provided. Finally, some representative cutting-edge biomedical applications of modified polymeric biomaterials, mainly including antifouling materials and biocompatible materials, are highlighted. On the basis of this literature study, a perspective on future trends in this field is provided.


Subject(s)
Biocompatible Materials/chemistry , Polymers/chemistry , Biomedical Research , Particle Size , Surface Properties
7.
Langmuir ; 35(9): 3470-3478, 2019 03 05.
Article in English | MEDLINE | ID: mdl-30727730

ABSTRACT

Mixed homopolymer brushes have unique interfacial properties that can be exploited for both fundamental studies and applications in technology. Herein, the synthesis of a new catechol-based biomimetic Y-shaped binary photoinitiator (Y-photoinitiator) and its applications for surface modification with polymer brushes through both "grafting to" and "grafting from" strategies are reported. The "leg" of the Y consists of a catechol group as surface anchoring moiety. The arms are photoinitiator moieties that can be "addressed" independent of each other by radiation of different wavelengths. Using ultraviolet and visible light successively, each arm of the Y-photoinitiator was activated, thereby allowing the synthesis of Y-shaped block copolymer brushes with dissimilar polymer chains. The suitability of the Y-photoinitiator for surface modification was first investigated using N-vinylpyrrolidone and styrene as the model monomers for successive UV-photoiniferter-mediated polymerization and visible-light-induced polymerization, respectively. Switching of the wetting properties of the Y-shaped block copolymer brush poly( N-vinylpyrrolidone)- block-poly(styrene) (PVP- b-PS)-grafted surfaces by contact with different solvents was also investigated. To further exploit this novel Y-photoinitiator for the preparation of functional interfaces, Y-shaped block copolymer brushes poly(1-(2-methacryloyloxyhexyl)-3-methylimidazolium bromide)- block-poly( N-vinylpyrrolidone- co-glycidyl methacrylate) (PIL(Br)- b-P(NVP- co-GMA)) were also prepared and subsequently functionalized with the cell-adhesive arginine-glycine-aspartic acid (RGD) peptides by reaction with the glycidyl groups (PILPNG-RGD). The PILPNG-RGD grafted surfaces showed excellent cell-adhesive, bacteriostatic, and bactericidal properties. Thus, it can be concluded that further exploitation of this novel Y-photoinitiator for graft polymerization should allow the preparation of a wide range of functional interfaces with tailored properties.

8.
Macromol Rapid Commun ; 40(20): e1900310, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31402490

ABSTRACT

A novel ring-closure strategy for cyclic polymers by combining reversible addition-fragmentation chain transfer polymerization (RAFT) and the sulfur(VI)-fluoride exchange (SuFEx) click reaction is presented. Herein, a new heterodifunctional trithiocarbonate RAFT agent, 2-((tert-butyldimethylsilyl)oxy)ethyl (4-(fluorosulfonyl)benzyl) carbonotrithioate (TBDMS-FSBCT), containing both tert-butyldimethylsilyl ether and sulfonyl fluoride moieties, is developed. The polymerization behavior of TBDMS-FSBCT is first demonstrated by a standard RAFT polymerization procedure for two types of vinyl monomers, N-isopropylacrylamide (NIPAAm) (conjugated vinyl monomer) and N-vinylpyrrolidone (NVP) (unconjugated vinyl monomer). The tert-butyldimethylsilyl ether and sulfonyl fluoride groups at the α and ω positions of the obtained linear polymer precursors (L-PNIPAAm and L-PVP) are verified by 1 H, 13 C, and 19 F NMR spectra. Subsequent intramolecular SuFEx click cyclization of the α,ω-heterofunctionalized linear precursors in air at room temperature conveniently yields the corresponding cyclic polymers (C-PNIPAAm and C-PVP). Overall, this is the first report on the preparation of cyclic polymers based on the SuFEx reaction under ambient conditions. It is envisioned that the approach may open an avenue for the formation of cyclic polymers.


Subject(s)
Click Chemistry/methods , Fluorides/chemistry , Polymerization , Polymers/chemistry , Sulfur/chemistry , Carbon-13 Magnetic Resonance Spectroscopy , Cyclization , Polymers/chemical synthesis , Proton Magnetic Resonance Spectroscopy , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
9.
Macromol Rapid Commun ; 40(21): e1900379, 2019 Nov.
Article in English | MEDLINE | ID: mdl-31513319

ABSTRACT

In addition to extensive studies of conventional linear poly(ionic liquids) (PILs), exploration of the effects of PIL topology, especially cyclic architecture, on bactericidal properties will expand the design possibilities for the development of excellent antibacterial surfaces. Herein, the preparation of antibacterial surfaces based on cyclic PIL brushes is reported for the first time and how the cyclic PIL architecture affects bactericidal activity is investigated. It is shown that the cyclic architecture imparted PIL brushes with enhanced bactericidal activity, achieving only 1.7% of bacterial viable percentage against gram-negative Escherichia coli using Live/Dead staining methods, compared to 6.6% for the corresponding linear PIL brushes. The enhanced bactericidal activity is also validated by the direct observation of scanning electron microscopy and a colony counting assay. Further mechanism studies reveal that the substantially different morphologies of cyclic aggregates and altered surface charge density induced by the cyclic PIL architecture can account for the enhanced bactericidal activity.


Subject(s)
Anti-Bacterial Agents/pharmacology , Escherichia coli/drug effects , Ionic Liquids/pharmacology , Polyelectrolytes/pharmacology , Anti-Bacterial Agents/chemistry , Escherichia coli/metabolism , Gold/chemistry , Gold/pharmacology , Ionic Liquids/chemistry , Microbial Sensitivity Tests , Molecular Structure , Optical Imaging , Particle Size , Polyelectrolytes/chemistry , Surface Properties
10.
Macromol Rapid Commun ; 39(3)2018 Feb.
Article in English | MEDLINE | ID: mdl-29144020

ABSTRACT

"Click" type reactions represent the currently most prevalent postpolymerization strategy for the preparation of functional polymeric materials. Herein, a novel photoiniferter agent 4-(fluorosulfonyl)benzyl diethylcarbamodithioate (FSB-DECT) containing both dithiocarbamates and sulfonyl fluoride moieties is developed to act as both photoinitiator and click sulfur(VI)-fluoride exchange (SuFEx) agent. The photopolymerization behavior of FSB-DECT is demonstrated via standard photoiniferter-mediated polymerization for various types of monomer including N-isopropylacrylamide (NIPAAm), glycidyl methacrylate, and vinyl acetate (VAc). Gel permeation chromatography data show that the polymerization is relatively well controlled, with polydispersity indices of the product homopolymers in the range of 1.3-1.6. 1 H and 19 F NMR spectra and "reinitiated" photopolymerization indicate that the sulfonyl fluoride and diethyldithiocarbamyl groups remain at the respective ends of the homopolymer chains. Furthermore, using the sulfonyl fluoride end-functionalized poly(N-isopropylacrylamide) as a model polymer, the utility of the SuFEx reaction for efficient postpolymerization functionalization is demonstrated.


Subject(s)
Benzoates/chemistry , Click Chemistry/methods , Ditiocarb/chemistry , Fluorides/chemistry , Sulfur/chemistry , Acrylamides/chemistry , Chromatography, Gel , Epoxy Compounds/chemistry , Methacrylates/chemistry , Photochemical Processes , Polymerization/radiation effects , Polymers/chemical synthesis , Polymers/chemistry , Sulfinic Acids/chemistry , Thiocarbamates/chemistry , Vinyl Compounds/chemistry
11.
Langmuir ; 31(44): 12054-60, 2015 Nov 10.
Article in English | MEDLINE | ID: mdl-26509287

ABSTRACT

A simple and versatile method for the preparation of surfaces to control bacterial adhesion is described. Substrates were first treated with two catechol-based polymerization initiators, one for thermal initiation and one for visible-light photoinitiation. Graft polymerization in sequence of dimethylaminoethyl methacrylate (DMAEMA) and 3-acrylamidebenzene boronic acid (BA) from the surface-bound initiators to form mixed polymer brushes on the substrate was then carried out. The PDMAEMA grafts were thermally initiated and the PBA grafts were visible-light-photoinitiated. Gold, poly(vinyl chloride) (PVC), and poly(dimethylsiloxane) (PDMS) were used as model substrates. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), and ellipsometry analysis confirmed the successful grafting of PDMAEMA/PBA mixed brushes. We demonstrated that the resulting surfaces showed charge-reversal properties in response to change of pH. The transition in surface charge at a specific pH allowed the surface to be reversibly switched from bacteria-adhesive to bacteria-resistant. At pH 4.5, below the isoelectric points (IEP, pH 5.3) of the mixed brushes, the surfaces are positively charged and the negatively charged Gram-positive S. aureus adheres at high density (2.6 × 10(6) cells/cm(2)) due to attractive electrostatic interactions. Subsequently, upon increasing the pH to 9.0 to give negatively charged polymer brush surface, ∼90% of the adherent bacteria are released from the surface, presumably due to repulsive electrostatic interactions. This approach provides a simple method for the preparation of surfaces on which bacterial adhesion can be controlled and is applicable to a wide variety of substrates.


Subject(s)
Acrylamides/chemistry , Bacterial Adhesion , Boronic Acids/chemistry , Methacrylates/chemistry , Nylons/chemistry , Photoelectron Spectroscopy , Spectroscopy, Fourier Transform Infrared , Static Electricity , Surface Properties
12.
Langmuir ; 30(19): 5474-80, 2014 May 20.
Article in English | MEDLINE | ID: mdl-24749896

ABSTRACT

To overcome the problem caused by the lability of the Au-S bond, we demonstrate the first use of Mn2(CO)10 for visible-light-induced surface grafting polymerization on Au surfaces in this paper. The visible-light-induced surface grafting of poly(N-isopropylacrylamide) (PNIPAAm) has the features of a "controlled" polymerization, which is characterized by a linear relationship between the thickness of the grafting layer and the monomer concentration. Ellipsometry indicated the formation of PNIPAAm films of up to ∼200 nm in thickness after only 10 min of polymerization at room temperature, demonstrating that this is a very fast process in comparison with traditional grafting polymerization techniques. Moreover, to demonstrate the potential applications of our approach, different substrates grafted by PNIPAAm and the covalent immobilization of a range of polymers on Au surfaces were also demonstrated. Considering the advantages of simplicity, efficiency, and mild reaction conditions as well as the ability of catecholic derivatives to bind to a large variety of substrates, this visible-light-induced grafting method is expected to be useful in designing functional interfaces.

13.
Colloids Surf B Biointerfaces ; 239: 113936, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38703556

ABSTRACT

Hydrophilic antifouling polymers provide excellent antifouling effects under usual short-term use conditions, but the long-term accumulation of contaminants causes them to lose their antifouling properties. To overcome this drawback, surface-initiated ring-opening graft polymerization (SI-ROP) was performed on the surface of the material by applying the cyclic carbide monomer 4'-(fluorosulfonyl)benzyl-5-methyl-2-oxo-1,3-dioxane-5-carboxylate (FMC), which contains a sulfonylfluoride group on the side chain, followed by a "sulfur(IV)-fluorine exchange" (SuFEx) post click modification reaction to link the hydrophilic polyethylene glycol (PEG) to the polyFMC (PFMC) brush, and a novel antifouling strategy for self-polishing dynamic antifouling surfaces was developed. The experimental results showed that the antifouling surface could effectively prevent the adsorption of proteins such as bovine serum albumin (BSA, ∼96.4%), fibrinogen (Fg, ∼87.8%) and lysozyme (Lyz ∼69.4%) as well as the adhesion of microorganisms such as the bacteria Staphylococcus aureus (S. aureus) (∼87.5%) and HeLa cells (∼67.2%). Moreover, the enzymatically self-polished surface still has excellent antifouling properties. Therefore, this modification method has potential applications in the field of biosensors and novel antifouling materials.


Subject(s)
Bacterial Adhesion , Biofouling , Polycarboxylate Cement , Polyethylene Glycols , Serum Albumin, Bovine , Staphylococcus aureus , Surface Properties , Staphylococcus aureus/drug effects , Polycarboxylate Cement/chemistry , Polyethylene Glycols/chemistry , Biofouling/prevention & control , Bacterial Adhesion/drug effects , Humans , Serum Albumin, Bovine/chemistry , Adsorption , Polymerization , Cattle , Animals , Fibrinogen/chemistry , Fibrinogen/metabolism , Hydrophobic and Hydrophilic Interactions , Muramidase/chemistry , Muramidase/metabolism , Muramidase/pharmacology
14.
ACS Appl Mater Interfaces ; 16(28): 35874-35886, 2024 Jul 17.
Article in English | MEDLINE | ID: mdl-38954798

ABSTRACT

To effectively solve the problem of significant loss of transplanted cells caused by thrombosis during cell transplantation, this study simulates the human fibrinolytic system and combines metabolic oligosaccharide engineering with strain-promoted azide-alkyne cycloaddition (SPAAC) click chemistry to construct a cell surface with fibrinolytic activity. First, a copolymer (POL) of oligoethylene glycol methacrylate (OEGMA) and 6-amino-2-(2-methylamido)hexanoic acid (Lys) was synthesized by reversible addition-fragmentation chain transfer (RAFT) copolymerization, and the dibenzocyclooctyne (DBCO) functional group was introduced into the side chain of the copolymer through an active ester reaction, resulting in a functionalized copolymer DBCO-PEG4-POL with ε-lysine ligands. Then, azide functional groups were introduced onto the surface of HeLa model cells through metabolic oligosaccharide engineering, and DBCO-PEG4-POL was further specifically modified onto the surface of HeLa cells via the SPAAC "click" reaction. In vitro investigations revealed that compared with unmodified HeLa cells, modified cells not only resist the adsorption of nonspecific proteins such as fibrinogen and human serum albumin but also selectively bind to plasminogen in plasma while maintaining good cell viability and proliferative activity. More importantly, upon the activation of adsorbed plasminogen into plasmin, the modified cells exhibited remarkable fibrinolytic activity and were capable of promptly dissolving the primary thrombus formed on their surfaces. This research not only provides a novel approach for constructing transplantable cells with fibrinolytic activity but also offers a new perspective for effectively addressing the significant loss of transplanted cells caused by thrombosis.


Subject(s)
Click Chemistry , Cycloaddition Reaction , Fibrinolysis , Oligosaccharides , Humans , HeLa Cells , Oligosaccharides/chemistry , Fibrinolysis/drug effects , Metabolic Engineering , Azides/chemistry , Polyethylene Glycols/chemistry , Methacrylates/chemistry , Alkynes/chemistry , Animals , Cell Survival/drug effects , Plasminogen/chemistry , Plasminogen/metabolism , Surface Properties
15.
Langmuir ; 29(1): 3-7, 2013 Jan 08.
Article in English | MEDLINE | ID: mdl-23245188

ABSTRACT

Silicon nanowire arrays (SiNWAs) were found to have catalytic activities similar to those of biological enzymes catalase and peroxidase. Thus not only can these materials catalyze the decomposition reaction of H(2)O(2) into water and oxygen, but they can also catalyze the oxidation of o-phenylenediamine (OPD), a common substrate for peroxidases, by H(2)O(2). The presence of Si-H bonds and the morphology of the SiNWAs are found to be crucial to the occurrence of such catalytic activity. When the SiNWAs are reacted with H(2)O(2), the data from Raman spectroscopy suggests the formation of (Si-H)(2)···(O species) ((Si-H)(2)···Os), which is presumably responsible for the catalytic activity. These findings suggest the potential use of SiNWAs as enzyme mimics in medicine, biotechnology, and environmental chemistry.


Subject(s)
Catalase/chemistry , Nanowires/chemistry , Peroxidase/chemistry , Silicon/chemistry , Catalysis , Hydrogen Peroxide/chemistry , Microarray Analysis , Molecular Structure , Oxidation-Reduction , Oxygen/chemistry
16.
Nanotechnology ; 24(10): 105101, 2013 Mar 15.
Article in English | MEDLINE | ID: mdl-23416357

ABSTRACT

We present our findings of the selective adsorption of native and denatured proteins onto thermally responsive, native-protein resistant poly(N-isopropylacrylamide) (PNIPAAm) decorated silicon nanowire arrays (SiNWAs). The PNIPAAm-SiNWAs surface, which shows very low levels of native-protein adsorption, favors the adsorption of denatured proteins. The amount of denatured-protein adsorption is higher at temperatures above the lower critical solution temperature (LCST) of PNIPAAm. Temperature cycling surrounding the LCST, which ensures against thermal denaturation of native proteins, further increases the amount of denatured-protein adsorption. Moreover, the PNIPAAm-SiNWAs surface is able to selectively adsorb denatured protein even from mixtures of different protein species; meanwhile, the amount of native proteins in solution is kept nearly at its original level. It is believed that these results will not only enrich current understanding of protein interactions with PNIPAAm-modified SiNWAs surfaces, but may also stimulate applications of PNIPAAm-SiNWAs surfaces for native/denatured protein separation.


Subject(s)
Nanotechnology/methods , Nanowires/chemistry , Protein Denaturation , Proteins/chemistry , Acrylamides/chemistry , Acrylic Resins , Adsorption , Materials Testing , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Microscopy, Fluorescence , Muramidase/chemistry , Polymers/chemistry , Silicon/chemistry , Surface Properties , Temperature , Time Factors
17.
Langmuir ; 28(25): 9451-9, 2012 Jun 26.
Article in English | MEDLINE | ID: mdl-22621226

ABSTRACT

Well-controlled polymerization of N-vinylpyrrolidone (NVP) on Au surfaces by surface-initiated atom transfer radical polymerization (SI-ATRP) was carried out at room temperature by a silanization method. Initial attempts to graft poly(N-vinylpyrrolidone) (PVP) layers from initiators attached to alkanethiol monolayers yielded PVP films with thicknesses less than 5 nm. The combined factors of the difficulty in the controllable polymerization of NVP and the instability of alkanethiol monolayers led to the difficulty in the controlled polymerization of NVP on Au surfaces. Therefore, the silanization method was employed to form an adhesion layer for initiator attachment. This method allowed well-defined ATRP polymerization to occur on Au surfaces. Water contact angle, X-ray photoelectron spectroscopy (XPS), and reflectance Fourier transform infrared (reflectance FTIR) spectroscopy were used to characterize the modified surfaces. The PVP-modified gold surface remained stable at 130 °C for 3 h, showing excellent thermal stability. Thus, postfunctionalization of polymer brushes at elevated temperatures is made possible. The silanization method was also applied to modify SPR chips and showed potential applications in biosensors and biochips.


Subject(s)
Gold/chemistry , Polymerization , Povidone/chemistry , Povidone/chemical synthesis , Temperature , Adsorption , Chemistry Techniques, Synthetic , Proteins/chemistry , Silanes/chemistry , Sulfhydryl Compounds/chemistry , Surface Plasmon Resonance , Surface Properties , Water/chemistry
18.
Langmuir ; 28(49): 17011-8, 2012 Dec 11.
Article in English | MEDLINE | ID: mdl-23157582

ABSTRACT

It is well known that adsorbed proteins play a major role in cell adhesion. However, it has also been reported that cells can adhere to a protein-resistant surface. In this work, the behavior of L02 and BEL-7402 cells on a protein-resistant, 3D topographical surface was investigated. The topographical gold nanoparticle layer (GNPL) surfaces were prepared by chemical gold plating, and the topography was described by roughness parameters acquired from a multiscale analysis. Both smooth Au and GNPL surfaces were modified with POEGMA polymer brushes using surface-initiated ATRP. The dry and hydrated thicknesses of POEGMA brushes on both smooth and rough surfaces were measured by AFM using a nanoindentation method. Protein adsorption experiments using (125)I radiolabeling revealed similarly low levels of protein adsorption on smooth and GNPL surfaces modified with POEGMA, thus allowing an investigation of the effects of topography on cell behavior under conditions of minimal protein adsorption. The roles of VN and FN adsorption in both L02 cells and BEL-7402 cells adhesion were investigated using cell culturing with and without a serum supplement. It was found that initial cell adhesion occurred via proteins adsorbed from the cell culture medium, whereas subsequent durable cell adhesion could be attributed to the topographical structure of the surface. Although cell spreading on protein-resistant surfaces was constrained because of the lack of adsorbed proteins, we found that cells adherent to topographical surfaces were more firmly attached and thus were more durable compared to those on smooth surfaces. In general, however, we conclude that topography is more important for cell adhesion on a protein-resistant surface.


Subject(s)
Coated Materials, Biocompatible/chemistry , Gold/chemistry , Hepatocytes/drug effects , Metal Nanoparticles/chemistry , Methacrylates/chemistry , Polyethylene Glycols/chemistry , Serum Albumin/chemistry , Adsorption , Cell Adhesion/drug effects , Cell Line , Cell Line, Tumor , Coated Materials, Biocompatible/pharmacology , Hepatocytes/cytology , Humans , Iodine Radioisotopes , Metal Nanoparticles/ultrastructure , Methacrylates/pharmacology , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Polyethylene Glycols/pharmacology , Polymethacrylic Acids , Surface Properties
19.
Analyst ; 137(8): 1779-84, 2012 Apr 21.
Article in English | MEDLINE | ID: mdl-22278156

ABSTRACT

The availability of techniques for the sensitive detection of early stage cancer is crucial for patient survival. Our previous research (Langmuir, 2011, 27, 2155-2158) showed that gold nanoparticle layers (GNPL) used in indirect format ELISA amplified the signal, and gave a lower limit of detection (LOD) compared with commercial ELISA plates. However, due to its intrinsic limitations, indirect ELISA is not suitable for samples of complex composition, such as serum, plasma, etc., thus limiting the clinical performance of this kind of ELISA. In the work reported here, a GNPL-based sandwich format ELISA was developed, which showed superiority in terms of detection limit and sensitivity in the determination of rabbit IgG in buffer. More importantly, experiments using plasma spiked with carcinoembryonic antigen (CEA) as a representative biomarker showed that our GNPL-based ELISA assay amplified the signal and lowered the LOD compared to other assays, including commercialized CEA ELISA kits. This simple and cost-effective GNPL-based sandwich ELISA holds promise in clinical applications.


Subject(s)
Enzyme-Linked Immunosorbent Assay/methods , Gold/chemistry , Metal Nanoparticles , Neoplasms/diagnosis , Carcinoembryonic Antigen/blood , Humans , Limit of Detection
20.
J Mater Chem B ; 10(2): 262-270, 2022 01 05.
Article in English | MEDLINE | ID: mdl-34889346

ABSTRACT

The simultaneous introduction of two new functionalities into the same polymeric substrate under mild reaction conditions is an interesting and important topic. Herein, dual-functional polydimethylsiloxane (PDMS) surfaces with antibacterial and antifouling properties were conveniently developed via a novel Y-shaped asymmetric dual-functional photoiniferter (Y-iniferter). The Y-iniferter was initially immobilized onto the PDMS surface by radical coupling under visible light irradiation. Afterwards, poly(2-hydroxyethyl methacrylate) (PHEMA) brushes and antibacterial ionic liquid (IL) fragments were simultaneously immobilized on the Y-iniferter-modified PDMS surfaces by combining the sulfur(VI)-fluoride exchange (SuFEx) click reaction and UV-photoinitiated polymerization. Experiments using E. coli as a model bacterium demonstrated that the modified PDMS surfaces had both the expected antibacterial properties of the IL fragments and the excellent antifouling properties of PHEMA brushes. Furthermore, the cytotoxicity of the modified PDMS surfaces to L929 cells was examined in vitro with a CCK-8 assay, which showed that the modified surfaces maintained excellent cytocompatibility. Briefly, this strategy of constructing an antibacterial and antifouling PDMS surface has the advantages of simplicity and convenience and might inspire the construction of diverse dual-functional surfaces by utilizing PDMS more effectively.


Subject(s)
Anti-Bacterial Agents/pharmacology , Biofouling/prevention & control , Dimethylpolysiloxanes/chemistry , Ionic Liquids/pharmacology , Sulfones/chemistry , Thioamides/chemistry , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/toxicity , Cell Line , Dimethylpolysiloxanes/toxicity , Escherichia coli/drug effects , Ionic Liquids/chemistry , Ionic Liquids/toxicity , Methacrylates/chemistry , Mice , Microbial Sensitivity Tests , Polyhydroxyethyl Methacrylate/chemistry , Polyhydroxyethyl Methacrylate/toxicity , Polymerization/radiation effects , Sulfones/radiation effects , Ultraviolet Rays
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