Poly Sulfobetaine Methacrylate Research Articles

Zwitterion-Modified Nanogel Responding to Temperature and Ionic Strength: A Dissipative Particle Dynamics Simulation.

The self-assembly and stimuli-responsive properties of nanogel poly(n-isopropylacrylamide) (p(NIPAm)) and zwitterion-modified nanogel poly(n-isopropylacrylamide-co-sulfobetainemethacrylate) (p(NIPAm-co-SBMA)) were explored by dissipative particle dynamics simulations. Simulation results reveal that for both types of nanogel, it is beneficial to form spherical nanogels at polymer concentrations of 5-10%. When the chain length (L) elongates from 10 to 40, the sizes of the nanogels enlarge. As for the p(NIPAm) nanogel, it shows thermoresponsiveness; when it switches to the hydrophilic state, the nanogel swells, and vice versa. The zwitterion-modified nanogel p(NIPAm-co-SBMA) possesses thermoresponsiveness and ionic strength responsiveness concurrently. At 293 K, both hydrophilic p(NIPAm) and superhydrophilic polysulfobetaine methacrylate (pSBMA) could appear on the outer surface of the nanogel; however, at 318 K, superhydrophilic pSBMA is on the outer surface to cover the hydrophobic p(NIPAm) core. As the temperature rises, the nanogel shrinks and remains antifouling all through. The salt-responsive property can be reflected by the nanogel size; the volumes of the nanogels in saline systems are larger than those in salt-free systems as the ionic condition inhibits the shrinkage of the zwitterionic pSBMA. This work exhibits the temperature-responsive and salt-responsive behavior of zwitterion-modified-pNIPAm nanogels at the molecular level and provides guidance in antifouling nanogel design.

Silk fibroin‐based conductive and antibacterial hydrogels with a dual network for flexible sensors

AbstractThe flexible wearable hydrogel strain sensors for human motion monitoring have attracted broad attention. However, developing a high‐strength hydrogel strain sensor remains challenging and achieves synergistic characteristics such as biocompatibility, antibacterial activity, and conductivity. This work proposes a two‐step UV polymerization method for the preparation of (hydrolyzed silk fibroin (HSF)/polyacrylamide (PAM)/polyacrylic acid (PAA)/poly sulfobetaine methacrylate (PSBMA) composite hydrogels. The monomers AM and AA undergo self‐polymerization and copolymerization. Meanwhile, SF is cross‐linked with them via multiple hydrogen bonds to form the first network. After the second UV initiation, SBMA polymerizes to create the second network. The HSF8%/PAM/PAA/PSBMA2%possesses superior tensile strength (1.49 ± 0.07 MPa) and compressive modulus (21.47 ± 1.07 MPa at 99% strain). The SBMA (4 wt%) endows hydrogels with antibacterial activity (98.53% ± 4.93%). The H+ionized by PAA and the ion channels constructed by SBMA (4 wt%) provide hydrogel with ionic conductivity (0.950 S m−1). The hydrogel could be used as a flexible strain sensor to monitor human joint activity. The natural silk fibroin allows the hydrogel to retain degradability. Therefore, the SF‐based conductive hydrogel shows the potential application in flexible strain sensors.

Low-Friction Hybrid Hydrogel with Excellent Mechanical Properties for Simulating Articular Cartilage Movement.

Hydrogels, which can withstand large deformations and have stable chemical properties, are considered a potential material for cartilage repair. However, hydrogels still face some challenges regarding their mechanical properties, tribological behavior, and biocompatibility. Thus, we synthesized a hybrid hydrogel by means of chemical cross-linking and transesterification using glycerol ethoxylate (GE) and zwitterionic polysulfobetaine methacrylate (PSBMA) as raw materials. The hybrid hydrogel showed excellent compressive stress at approximately 3.50 MPa and low loss factors (0.023-0.049). Moreover, because GE has good water binding properties, helping to form a stable hydration layer and maintain low energy dissipation, a low friction coefficient (μ ≈ 0.028) was obtained with the "soft-soft contact mode" of a hydrogel hemisphere and hydrogel disc under reciprocating motion. In vitro cytotoxicity, skin sensitization, and irritation reaction tests were carried out to show good biocompatibility of the GE-PSBMA hybrid hydrogel. In this study, a hybrid hydrogel with no potential cytotoxicity, strong compressive capacity, and excellent lubricity was obtained to provide a potential alternative for developing polymer hybrids, as well as demonstrating an idea for the application of hybrid hydrogels in cartilage replacement.

Zwitterionic Polysulfobetaine Coating and Antiplatelet Liposomes Reduce Fouling in Artificial Lung Circuits.

The artificial lung has provided life-saving support for pulmonary disease patients and recently afforded patients with severe cases of COVID-19 better prognostic outcomes. While it addresses a critical medical need, reducing the risk of clotting inside the device remains challenging. Herein, a two-step surface coating process of the lung circuit using Zwitterionic polysulfobetaine methacrylate is evaluated for its nonspecific protein antifouling activity. It is hypothesized that similarly applied coatings on materials integrated (IT) or nonintegrated (NIT) into the circuit will yield similar antifouling activity. The effects of human plasma preconditioned with nitric oxide-loaded liposome on platelet (plt) fouling are also evaluated. Fibrinogen antifouling activities in coated fibers are similar in the IT and NIT groups. It however decreases in coated polycarbonate (PC) in the IT group. Also, plt antifouling activity in coated fibers is similar in the IT and NIT groups and is lower in coated PC and Tygon in the IT group compared to the NIT group. Coating process optimization in the IT lung circuit may help address difference in the coating appearance of outer and inner fiber bundle fibers, and the NO-liposome significantly reduces (86%) plt fouling on fibers indicating its potential use for blood anticoagulation.

Preparation of Temperature-Sensitive SiO2–PSBMA for Reducing the Viscosity of Heavy Oil

Viscosity reduction by emulsification is one of the most effective methods for the recovery of heavy oil. Nanoparticles with low toxicity and low cost can stabilize oil-in-water (O/W) Pickering emulsions to reduce the viscosity of heavy oil and thereby have become a new type of emulsifier in recent years. The stimuli-responsive emulsions formed by responsive particles can achieve emulsification and demulsification under external stimuli, providing convenient conditions for heavy oil transportation and recovery, where the temperature response is easier to achieve. In this study, six groups of temperature-sensitive SiO2–PSBMA (PSBMA: polysulfobetaine methacrylate) with different particle sizes were prepared by the reverse atom transfer radical polymerization (RATRP) method. The morphologies of SiO2 particles before and after grafting were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM), and the structure of the product was characterized by Fourier transform infrared (FT-IR) spectroscopy, which showed that PSBMA was successfully grafted to SiO2. The grafting ratios (η) of six groups of SiO2–PSBMA measured by thermogravimetric analysis (TGA) were similar (34.50–42.94%). The temperature sensitivity of SiO2–PSBMA was determined by dynamic light scattering (DLS) and the contact angles at different temperatures, which showed that its upper critical solution temperature (UCST) was about 40–50 °C. SiO2–PSBMA was applied to GD2 heavy oil to reduce the viscosity at 60 °C, which showed that the SiO2–PSBMA had a good emulsification effect. With the increase of particle size, the viscosity reduction rate (VRR) showed a trend of first increase and then decrease. The highest VRR was 96.41%, achieved by 227.61 nm SiO2–PSBMA. All of the emulsions stabilized by SiO2–PSBMA were able to demulsify at room temperature. It can be used as an intelligent temperature-responsive viscosity reducer for heavy oil to control emulsions on demand.

“Self-Defensive” Antifouling Zwitterionic Hydrogel Coatings on Polymeric Substrates

In biomedicine fields, biofouling can easily occur on devices such as sensors and catheters, causing some iatrogenic infections, which menace the lives and health of patients greatly. Therefore, it is of great significance to solve the problems of bacterial infection on the surfaces of medical devices. In this paper, "self-defensive" and antifouling zwitterionic hydrogel coatings were prepared by network interpenetration of the hydrogel and the polymeric substrates. The zwitterionic polysulfobetaine methacrylate (PSBMA) hydrogel coatings resisted most of the bacteria to adhere on the substrates. When a few bacteria were lucky to escape the antifouling defense and adhered to the coatings, gentamicin sulfate (GS) would be released under the trigger of a weakly acidic environment caused by bacterial metabolism to kill these bacteria. Simultaneously, the coatings of the bacteria-adhering sites would be degraded by hyaluronidase secreted by these bacteria and peeled off to remove the bacteria and renew the antifouling surfaces. The antifouling properties and mechanism of the self-defensive behavior of the hydrogel coatings on polymeric substrates were investigated. Furthermore, the in vitro and in vivo antibacterial performances, as well as the biocompatibility of the coatings, were demonstrated. The results suggested that the self-defensive antifouling zwitterionic hydrogel coatings hold great potential to be used on the surfaces of polymeric medical devices.

Catechol-functionalized sulfobetaine polymer for uniform zwitterionization via pH transition approach

The study aims to develop a modification strategy to facilitate uniform catechol-assisted zwitterionization on nitinol alloy for bio-compatibility and fouling resistance. Catechol-functionalized polysulfobetaine methacrylate (pSBMA/DA) is synthesized via dopamine-initiated photo-polymerization. Under UV irradiation, semiquinone radicals from dopamine (DA) can be generated, and prevented loss of one electron to intramolecular cyclization and intermolecular dimerization in a solution at pH 2. Pseudo-first-order polymerization kinetics, and relations of apparent rate constant and number average molecular weight with the molar ratio of DA in photopolymerization for pSBMA/DA are unveiled. In a solution at pH 3, PSBMA/DA begins aggregation, kept catechol moieties from premature oxidization, and enabled even deposition on the nitinol substrate. After pH regulation to 8.5, pSBMA/DA extends, and concurrently catechol moieties are activated to interact with the nitinol surface via the formation of bidentate binding. X-ray photoelectron spectroscopy (XPS) analysis revealed that a shorter pSBMA/DA chain with higher catechol content provides more anchoring sites to enhance zwitterionic moieties coverage on substrates. Interestingly, atomic force microscopy (AFM) images revealed a smooth and uniform deposition of pSBMA/DA using the pH-transition method. Strong ionic hydration of pSBMA/DA coating on nitinol surface repels non-specific adsorption of bio-foulants, permitting excellent antifouling properties. Zwitterion-modified nitinol achieved a reduction rate of 99.9% against Escherichia coli and Staphylococcus aureus attachment. In addition, pSBMA/DA exhibits a robust antifouling performance to NIH 3T3 mouse fibroblasts in culture media after incubation for 24 h. Overall, the pSBMA/DA coating via pH transition approach opens up a promising strategy to facilitate uniform surface functionalization for antifouling and coating technology.

A Novel Surface Modification Strategy via Photopolymerized Poly-Sulfobetaine Methacrylate Coating to Prevent Bacterial Adhesion on Titanium Surfaces.

Recent investigations on the anti-adhesive properties of polysulfobetaine methacrylate (pSBMA) coatings had shown promising potential as antifouling surfaces and have given the impetus for the present paper, where a pSBMA coating is applied via photopolymerization on a macro-roughened, sandblasted, and acid-etched titanium implant surface in order to assess its antifouling properties. Current emphasis is placed on how the coating is efficient against the adhesion of Enterococcus faecalis by quantitative assessment of colony forming units and qualitative investigation of fluorescence imaging and scanning electron microscopy. pSBMA coatings via photopolymerization of titanium surfaces seems to be a promising antiadhesion strategy, which should bring substantial benefits once certain aspects such as biodegradation and osseointegration were addressed. Additionally, commercial SAL-titanium substrates may be coated with the super-hydrophilic coating, appearing resistant to physiological salt concentrations and most importantly lowering E. faecalis colonization significantly, compared to titanium substrates in the as-received state. It is very likely that pSBMA coatings may also prevent the adhesion of other germs.

Surface energy characteristics of zeolite embedded PVDF nanofiber films with electrospinning process

Electrospinning is a nano-scale fiber production method with various polymer materials. This technique allows simple fiber diameters control by changing the physical conditions such as applied voltage and polymer solution viscosity during the fabrication process. The electrospun polymer fibers form a thin porous film with high surface area to volume ratio. Due to these unique characteristics, it is widely used for many application fields such as photocatalyst, electric sensor, and antibacterial scaffold for tissue engineering. Filtration is one of the main applications of electrospun polymer fibers for specific application of filtering out dust particles and dehumidification. Most polymers which are commonly used in electrospinning are hard to perform the filtering and dehumidification simultaneously because of their low hygroscopic property. To overcome this obstacle, the desiccant polymers are developed such as polyacrylic acid and polysulfobetaine methacrylate. However, the desiccant polymers are generally expensive and need special solvent for electrospinning. An alternating way to solve these problems is mixing desiccant material like zeolite in polymer solution during an electrospinning process. In this study, the free surface energy characteristics of electrospun polyvinylidene fluoride (PVDF) film with various zeolite concentrations are investigated to control the hygroscopic property of general polymers. Fundamental physical property of wettability with PVDF shows hydrophobicity. The electrospun PVDF film with small weight ratio with higher than 0.1% of zeolite powder shows diminished contact angles that certifying the wettability of PVDF can be controlled using desiccant material in electrospinning process. To quantify the surface energy of electrospun PVDF films, sessile water droplets are introduced on the electrospun PVDF film surface and the contact angles are measured. The contact angles of PVDF film are 140° for without zeolite and 80° for with 5wt% of zeolite respectively. As a result, the surface energy of PVDF film can be controlled by embedding zeolite particles in electrospinning process and applied to filtration application of dust filtering and dehumidification simultaneously with low manufacturing cost.

Water and salt transport properties of zwitterionic polymers film

Two series of crosslinked zwitterionic polymer films were synthesized via UV-photopolymerization of aqueous solution, and the films were prepared using sulfobetaine methacrylate (SBMA) or carboxybetaine methacrylate (CBMA) as the zwitterionic co-monomer and poly(ethylene glycol) diacrylate (PEGDA) as the crosslinker. The water and salt transport properties of the obtained polysulfobetaine methacrylate (PSBMA) and polycarboxybetaine methacrylate (PCBMA) films were studied using permeation and kinetic desorption methods with crosslinked poly(ethylene glycol) acrylate (PEGA) films as a control. Zwitterionic films absorb more water and are more permeable to both water and salt than PEGA films as a result of interactions between the zwitterions, water molecules, and salt ions. The transport properties of PSBMA and PCSMA depend similarly on crosslinking density, and high water and salt permeability correlates with high water uptake. However, the relationship between salt permeability and salt concentration differed between PSBMA and PCBMA. PSBMA behaves like a charged film, and its salt permeability increases with salt concentration while PCBMA shows the opposite trend. Transport properties for both materials are consistent with a trade-off between water permeability and water/salt selectivity. Zwitterionic films exhibit high permeability/low selectivity among polymers reported in the literature. This result suggests that they could be useful as coating materials for membrane fouling control where the anti-fouling properties of the zwitterionic material is more important than water/salt selectivity.

Surface charge control for zwitterionic polymer brushes: Tailoring surface properties to antifouling applications

HypothesisElectrostatic interactions play an important role in adhesion phenomena particularly for biomacromolecules and microorganisms. Zero charge valence of zwitterions has been claimed as the key to their antifouling properties. However, due to the differences in the relative strength of their acid and base components, zwitterionic materials may not be charge neutral in aqueous environments. Thus, their charge on surfaces should be further adjusted for a specific pH environment, e.g. physiological pH typical in biomedical applications. ExperimentsSurface zeta potential for thin polymeric films composed of polysulfobetaine methacrylate (pSBMA) brushes is controlled through copolymerizing zwitterionic SBMA and cationic methacryloyloxyethyltrimethyl ammonium chloride (METAC) via surface-initiated atom transfer polymerization. Surface properties including zeta potential, roughness, free energy and thickness are measured and the antifouling performance of these surfaces is assessed. FindingsThe zeta potential of pSBMA brushes is −40mV across a broad pH range. By adding 2% METAC, the zeta potential of pSBMA can be tuned to zero at physiological pH while minimally affecting other physicochemical properties including dry brush thickness, surface free energy and surface roughness. Surfaces with zero and negative zeta potential best resist fouling by bovine serum albumin, Escherichia coli and Staphylococcus aureus. Surfaces with zero zeta potential also reduce fouling by lysozyme more effectively than surfaces with negative and positive zeta potential.

Rheological behavior of hydrophobically modified polysulfobetaine methacrylate aqueous solution

Polysulfobetaine methacrylate (PSBMA) that was hydrophobically modified with methacrylic acid 2,3-epoxypropyl ester (GMA) was synthesized via micellar copolymerization method. Viscosity of the hydrophobically modified PSBMA solution was sensitive to added salt concentration.

Enhancing membrane performance by blending ATRP grafted PMMA–TiO2 or PMMA–PSBMA–TiO2 in PVDF

To improve PVDF (polyvinylidine fluoride) membrane property, TiO2 nano-particles can be blended in casting solutions to form composite membranes. In this study, TiO2 nano-particles were modified by coupling with γ-aminopropyl triethoxy silane (KH550), then grafted with PMMA (Polymethyl methacrylate) or co-grafted with PMMA and more hydrophilic PSBMA (polysulfobetaine methacrylate) via ATRP (atom transfer radical polymerization). ATRP grafting time and weight ratio of KH550 to TiO2 were two main identified factors affecting TiO2 modification and membrane hydrophilicity, flux and antifouling properties. These were shown by Scanning electron microscopy (SEM) characterization, contact angles measurements and filtration tests with yeast suspensions. The grafted TiO2–PMMA nano particles formed after coupling at 3:1 weight ratio of KH550 to TiO2 and 5h grafting, once composited with PVDF, formed a membrane with higher flux (up to 50%), higher flux recovery rate (FRR, 93.5%) and lower irreversible fouling (5.37%) than PVDF membrane composited with unmodified TiO2. Blending TiO2 co-grafted with PMMA and zwitterionic polymer PSBMA resulted in even better antifouling membranes (even lower Rir<2% and even higher FRR 99%). When the molar ratio of MMA to SBMA was 2 to 1, the highest steady flux and the highest FRR were obtained.

Molecular Dynamics Simulations of Surface Hydration Layers Near Non-fouling Polymer Membranes

The prevention of nonspecific protein adsorption was a big challenge in biomedical and marine fields. Recent studies of the mechanisms of non-fouling materials have identified a strong correlation between material surface hydration and resistance to nonspecific protein adsorption. To investigate the molecular mechanism of two typical non-fouling materi- als PDMS and pSBMA on molecular level, a series of molecular dynamics simulations were conducted. This work concen- trated on the structure properties and dynamic behaviors of water molecules that belong to the non-fouling membranes' sur- face hydration layers. Water's behavior near the membrane were analyzed in energetic, dynamics and structure aspects: PMFs (potential of mean force) between hydration layer water and polymer surfaces indicated pSBMA has more advantages on binding water molecules energetically; the analyzing of diffusion coefficients, residence time, and dipole residence time of hydration layer water showed pSBMA has slower dynamics properties which demonstrate water molecules were tightly bonded by pSBMA; the illustration of atoms density profile, hydrogen bond and their number distribution showed a rich hy- drogen bond network structure around pSBMA. Based on above, following conclusions were then speculated: 1) the hydra- tion layer near non-fouling membrane has a strong relationship with the nonspecific protein adsorption which forms a physi- cal and energy barrier during particles in solution (including proteins) come into contact with non-fouling membranes. 2) Comparing with PDMS, pSBMA as a zwitterionic polymer can bind water molecules more strongly via both electrostatic and hydrogen bonding. And the caging effects of water network formed around pSBMA can also reduce water molecules' mobil- ity. All these lead to a stable hydration layer that prevents non-specific protein adsorption. Simply, pSBMA generated a more energetic advantaged, tightly bounded and structured water layer by electrostatic, hydrogen bonding and caging effect. This hydration layer prevents protein from approaching the surface, resulting in a better non-fouling surface than PDMS. Keywords poly-dimethylsiloxane; poly-sulfobetaine methacrylate; bio-fouling; non-fouling material; molecular dynamics

Zwitterionic fluorescent nanoparticles prepared using BODIPY conjugated polysulfobetaines for cancer cell imaging

Zwitterionic fluorescent nanoparticles are developed by using polysulfobetaine methacrylate, NIPAAm and BODIPY fluorophores to identify the cancer cells in response to intra and extracellular stimuli. The fluorescent nanoparticles exhibit minimal fluorescence intensity at physiological temperature and pH, while strong emissions are observed in acidic and basic environments enabling the nanoparticles to act as novel fluorescence probes.

Surface hydrophilization of microporous polypropylene membrane by grafting zwitterionic polymer for anti-biofouling

The anti-biofouling properties, i.e. the resistance to protein adsorption and the inhibition of bacterial adhesion (biofilm formation) are of vital importance to separation membranes. Surface hydrophilization is thought to be the most common approach to improve these performances for hydrophobic polymer membranes, such as microporous polypropylene membrane (MPPM). In this work, MPPM was highly hydrophilized by the UV-induced grafting of polysulfobetaine methacrylate (polySBMA), an outstanding representative of zwitterionic anti-/non-fouling polymers. A sequential grafting strategy was improved by combining the conventional benzophenone entrapment and covalent immobilization methods. FT-IR/ATR, XPS and FESEM were used to characterize the detailed surface structures of MPPM. The hydrophilization effect was evaluated by water contact angle (WCA) and pure water flux measurements. Besides, both protein filtration and initial adhesion of bacteria were performed to investigate the anti-biofouling properties of the modified MPPM. The surface hydrophobicity of the bacteria was also measured and correlated with the adhesion results. It is found that the improved strategy allows the grafting to take place on the external surface and the grafting density to be well controlled by modulating the SBMA concentration. The surface hydrophilicity of MPPM is significantly enhanced, characterized by a decrease of WCA from 145 to ∼15° and an increase of flux by 4 times. These hydrophilized MPPM has strong resistance to protein fouling, having a flux recovery ratio higher than 95% under optimized conditions. The initial adhesion of bacteria on the MPPM can be completely suppressed when the grafting density reaches 560 μg/cm 2, regardless of the bacterial surface hydrophobicity.