Characterization of Hydration Water Bound to Choline Phosphate-Containing Polymers

Engineering Low Volume Resuscitants for the Prehospital Care of Severe Hemorrhagic Shock

Globally, traumatic injury is a leading cause of suffering and death. The ability to curtail damage and ensure survival after major injury requires a time-sensitive response balancing organ perfusion, blood loss, and portability, underscoring the need for novel therapies for the prehospital environment. Currently, there are few options available for damage control resuscitation (DCR) of trauma victims. We hypothesize that synthetic polymers, which are tunable, portable, and stable under austere conditions, can be developed as effective injectable therapies for trauma medicine. In this work, we design injectable polymers for use as low volume resuscitants (LVRs). Using RAFT polymerization, we evaluate the effect of polymer size, architecture, and chemical composition upon both blood coagulation and resuscitation in a rat hemorrhagic shock model. Our therapy is evaluated against a clinically used colloid resuscitant, Hextend. We demonstrate that a radiant star poly(glycerol monomethacrylate) polymer did not interfere with coagulation while successfully correcting metabolic deficit and resuscitating animals from hemorrhagic shock to the desired mean arterial pressure range for DCR - correcting a 60 % total blood volume (TBV) loss when given at only 10 % TBV. This highly portable and non-coagulopathic resuscitant has profound potential for application in trauma medicine.

Enzyme stability in polymer hydrogel-enzyme hybrid nanocarrier containing phosphorylcholine group

Enzymes are biological catalysts with good biocompatibility and high efficiency and have been widely used in many fields, such as wastewater treatment, biosensors, and the medical industry. However, their inherently low stability under conditions of practical use limits further applications. Zwitterionic polymers possessing a pair of oppositely charged groups in their repeating units can increase protein stability because of their good biocompatibility and high water content. In this study, zwitterionic copolymer nanogels comprising poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-methacrylic acid-N-hydroxy succinimide ester (MNHS)) (PMS) were synthesized via reversible addition-fragmentation chain-transfer polymerization (RAFT). β-Galactosidase (β-gal) was post-modified within zwitterionic polymer nanogels with a covalently-bound spacer and the activity was compared with that of directly immobilized β-gal and free β-gal. Compared with direct immobilization, covalent immobilization with a spacer could reduce the structural change of β-gal, as confirmed by the circular dichroism spectra. Although the activity of β-gal decreased after immobilization, the hybrids of the β-gal immobilized nanogels, termed hybrid nanogel-enzymes, demonstrated superior stability compared to the free enzymes. The hybrid nanogel-enzymes maintained their function against inactivation by organic solvents and proteinases owing to their high water content, anti-biofouling properties, and limited mass transfer. They can also withstand protein aggregation at high temperatures and maintain their activity. Compared to direct immobilization, immobilization with a spacer resulted in a dramatic increase in the enzyme activity and a slight decrease in the stability. These results indicate that polymer nanogels containing phosphorylcholine units are promising materials for enzyme immobilization, expanding the scope of enzyme applications.

Machine-Learning-Aided Understanding of Protein Adsorption on Zwitterionic Polymer Brushes

Constructing antifouling surfaces is a crucial technique for optimizing the performance of devices such as water treatment membranes and medical devices in practical environments. These surfaces are achieved by modification with hydrophilic polymers. Notably, zwitterionic (ZI) polymers have attracted considerable interest because of their ability to form a robust hydration layer and inhibit the adsorption of foulants. However, the importance of the molecular weight and density of the ZI polymer on the antifouling property is partially understood, and the surface design still retains an empirical flavor. Herein, we individually assessed the influence of the molecular weight and density of the ZI polymer on protein adsorption through machine learning. The results corroborated that protein adsorption is more strongly influenced by density than by molecular weight. Furthermore, the distribution of predicted protein adsorption against molecular weight and polymer density enabled us to determine conditions that enhanced (or weaken) antifouling. The relevance of this prediction method was also demonstrated by estimating the protein adsorption over a wide range of ionic strengths. Overall, this machine-learning-based approach is expected to contribute as a tool for the optimized functionalization of materials, extending beyond the applications of ZI polymer brushes.

Embedding Thiols into Choline Phosphate Polymer Zwitterions

The compositional scope of polymer zwitterions has grown significantly in recent years and now offers designer synthetic materials that are broadly applicable across numerous areas, including supracolloidal structures, electronic materials interfaces, and macromolecular therapeutics. Among recent developments in polymer zwitterion syntheses are those that allow insertion of reactive functionality directly into the zwitterionic moiety, yielding new monomer and polymer structures that hold potential for maximizing the impact of zwitterions on the macromolecular materials chemistry field. This manuscript describes the preparation of zwitterionic choline phosphate (CP) methacrylates containing either aromatic or aliphatic thiols embedded directly into the zwitterionic moiety. The polymerization of these functional CP methacrylates by reversible addition-fragmentation chain-transfer methodology yields polymeric zwitterionic thiols containing protected thiol functionality in the zwitterionic units. After polymerization, the protected thiols are liberated to yield thiol-rich polymer zwitterions which serve as precursors to subsequent reactions that produce polymer networks as well as polymer-protein bioconjugates.

Measurement of the Adhesion Force of a Living Sessile Organism on Antifouling Coating Surfaces Prepared with Polysulfobetaine-Grafted Particles

An antifouling polymer brush-like structure was fabricated by a simple and versatile dip-coating method of sulfobetaine containing copolymer-grafted silica nanoparticles (SiNPs) and alkyl diiodide cross-linkers. Surface-initiated atom transfer radical copolymerization of 3-(N-2-methacryloyloxyethyl-N,N-dimethyl)ammonatopropanesulfonate (MAPS) and N,N-dimethylaminoethyl methacrylate (DMAEMA) was carried out from initiator-immobilized SiNPs to give poly(MAPS-co-DMAEMA)-grafted SiNPs (MAPS/DMAEMA = 9/1, mol/mol) with diameters of 150-170 nm. The SiNP-g-copolymer/2,2,2-trifluoroethanol solution was dip-coated on silicon and glass substrates. Successive treatment with 1,4-diiodobutane in methanol gave a hydrophilic cross-linked coating film for the SiNP-g-copolymer. The cross-linked particle brushes did not peel off from the substrate even after washing with water in an ultrasonic cleaner despite the simple physical absorption of the SiNP-g-copolymer on the substrate surface. The adhesion force of the tentacle of a living barnacle cyprid on a glass surface covered with the cross-linked SiNP-g-copolymer was directly measured by scanning probe microscopy in seawater. The coating film exhibited extremely low adhesion to the cypris larva in the seawater, expecting this to be an effective antifouling property.

Flow diverter surface modifications for aneurysm treatment: A review of the mechanisms and data behind existing technologies

Flow diversion (FD) has become a mainstay treatment for large wide-necked aneurysms. Despite excellent safety and efficacy, the risk of thromboembolic complications necessitates the use of dual antiplatelet therapy (DAPT). The use of DAPT makes hemorrhagic complications of stenting carry high morbidity and mortality. Additionally, DAPT usage carries a risk of "nuisance" complications that do not directly impact intracranial circulation but need to be managed nonetheless. To circumvent this issue, the most recent generation of flow diverters have undergone surface modification with various compounds to confer blood compatibility to limit clotting and thrombosis. While these newer generation flow diverters are marketed to enhance ease of deployment, the goal is to eventually facilitate single antiplatelet use with flow diverter treatment. This generation of FDs have potential to expand indications beyond unruptured wide-necked aneurysms to include ruptured intracranial aneurysms without the necessity of DAPT. Currently, no comprehensive review details the molecular mechanisms and pre-clinical and clinical data on these modifications. We seek to fill this gap in the literature by consolidating information on the coating technology for four major FDs currently in clinical use-PipelineTM Flex and Vantage Shield TechnologyTM, FREDTMX, p48/64 hydrophilic coating, and Acandis Dervio® 2heal-to serve as a reference guide in neurointerventional aneurysm treatment. Although the Balt silkTM was one of the first FDs, it is uncoated, thus we will not cover this device in our review. A literature review was performed to obtain information on each coating technology for the major flow diverters currently on the market using international databases (PUBMED, Embase, Medline, Google Scholar). The search criteria used the keywords for each coating technology of interest "phosphorylcholine," "poly 2-methoxyethyl acrylate," "hydrophilic polymer coating," and "fibrin-heparin" Keywords related to the device names "Pipeline Shield," "Pipeline Shield with Flex Technology," "FRED," "FREDX," "p64," "p64-HPC," "Derivo 2heal" were also used. Studies that detailed the mechanism of action of the coating, any pre-clinical studies with surface-modified intravascular devices, and any clinical retrospective series, prospective series, or randomized clinical trials with surface-modified devices for aneurysm treatment were included.

Biomimetic materials based on zwitterionic polymers toward human-friendly medical devices

This review summarizes recent research on the design of polymer material systems based on biomimetic concepts and reports on the medical devices that implement these systems. Biomolecules such as proteins, nucleic acids, and phospholipids, present in living organisms, play important roles in biological activities. These molecules are characterized by heterogenic nature with hydrophilicity and hydrophobicity, and a balance of positive and negative charges, which provide unique reaction fields, interfaces, and functionality. Incorporating these molecules into artificial systems is expected to advance material science considerably. This approach to material design is exceptionally practical for medical devices that are in contact with living organisms. Here, it is focused on zwitterionic polymers with intramolecularly balanced charges and introduce examples of their applications in medical devices. Their unique properties make these polymers potential surface modification materials to enhance the performance and safety of conventional medical devices. This review discusses these devices; moreover, new surface technologies have been summarized for developing human-friendly medical devices using zwitterionic polymers in the cardiovascular, cerebrovascular, orthopedic, and ophthalmology fields.