Crosslinked Polypeptide Films via RAFT-Mediated Continuous Assembly of Polymers.

Polypeptide coatings are a cornerstone in the field of surface modification due to their widespread biological potential. As their properties are dictated by their structural features, subsequent control thereof using unique fabrication strategies is important. Herein, we report a facile method of precisely creating densely crosslinked polypeptide films with unusually high random coil content through continuous assembly polymerization via reversible addition-fragmentation chain transfer (CAP-RAFT).

Platelet procoagulant potential is reduced in platelet concentrates ex vivo but appears restored following transfusion.

Background: The procoagulant profile of platelet concentrates (PCs) following transfusion has been difficult to evaluate due to lack of specific markers. This study aimed to characterize procoagulant platelets in PCs and the effect of transfusion.

Study Design And Methods: Buffy coat-derived PCs from 12 donors were pooled, split, then stored conventionally, cold (2-6°C) or cryopreserved (-80°C).

Refrigeration of apheresis platelets in platelet additive solution (PAS-E) supports in vitro platelet quality to maximize the shelf-life.

Background: Refrigeration, or cold-storage, of platelets may be beneficial to extend the limited shelf-life of conventionally stored platelets and support transfusion protocols in rural and military areas. The aim of this study was to compare the morphologic, metabolic, and functional aspects of apheresis platelets stored at room-temperature (RT) or cold conditions, in either plasma or supplemented with platelet additive solution (PAS).

Study Design And Methods: Double-dose apheresis platelets were collected in either 100% plasma or 40% plasma/60% PAS-E using the Trima apheresis platform.

Reconstituted cryopreserved platelets synthesize proteins during short-term storage and packaging a defined subset into microvesicles.

Background: Cryopreservation of platelets (PLTs) could allow extension of their shelf-life to years, compared to days for liquid stored platelets. Due to their greater hemostatic effect, reconstituted cryopreserved platelets (cryo-PLTs) would be able to support bleeding emergencies. Since protein synthesis has been linked to PLT functions, such as clot formation and immune responses, the translational capacity of reconstituted cryo-PLTs was assessed upon thawing and short-term storage.

Extended storage of thawed platelets: Refrigeration supports postthaw quality for 10 days.

Background: Cryopreservation of platelets with dimethylsulfoxide (DMSO) at -80°C increases their shelf life from days to years. Once thawed, platelets are stored at room temperature (RT), and the shelf life is limited to 4-6 hours. However, refrigeration (cold storage) may facilitate a prolongation of the shelf life of thawed platelets.

Spider-silk inspired polymeric networks by harnessing the mechanical potential of β-sheets through network guided assembly.

The high toughness of natural spider-silk is attributed to their unique β-sheet secondary structures. However, the preparation of mechanically strong β-sheet rich materials remains a significant challenge due to challenges involved in processing the polymers/proteins, and managing the assembly of the hydrophobic residues. Inspired by spider-silk, our approach effectively utilizes the superior mechanical toughness and stability afforded by localised β-sheet domains within an amorphous network.

Ultrathin Metal-Organic Framework Nanosheets as a Gutter Layer for Flexible Composite Gas Separation Membranes.

Ultrathin metal-organic framework (MOF) nanosheets show great potential in various separation applications. In this study, MOF nanosheets are incorporated as a gutter layer in high-performance, flexible thin-film composite membranes (TFCMs) for CO separation. Ultrathin MOF nanosheets (∼3-4 nm) were prepared via a surfactant-assisted method and subsequently coated onto a flexible porous support by vacuum filtration.

Blood-Catalyzed RAFT Polymerization.

The use of hemoglobin (Hb) contained within red blood cells to drive a controlled radical polymerization via a reversible addition-fragmentation chain transfer (RAFT) process is reported for the first time. No pre-treatment of the Hb or cells was required prior to their use as polymerization catalysts, indicating the potential for synthetic engineering in complex biological microenvironments without the need for ex vivo techniques. Owing to the naturally occurring prevalence of the reagents employed in the catalytic system (Hb and hydrogen peroxide), this approach may facilitate the development of new strategies for in vivo cell engineering with synthetic macromolecules.

On-Demand Cascade Release of Hydrophobic Chemotherapeutics from a Multicomponent Hydrogel System.

A multicomponent hydrogel drug-delivery platform with covalent incorporation of core-cross-linked star (CCS) polymers has been fabricated through dual cross-linking reactions. The presence of amphiphilic CCS polymers enhances the mechanical stability of the network and allows for immobilization of hydrophobic chemotherapeutics (e.g.

Characterization of biologic response modifiers in the supernatant of conventional, refrigerated, and cryopreserved platelets.

Background: Alternatives to room temperature storage of platelets (PLTs) are of interest to support blood banking logistics. The aim of this study was to compare the presence of biologic response modifiers (BRMs) in PLT concentrates stored under conventional room temperature conditions with refrigerated or cryopreserved PLTs.

Study Design And Methods: A three-arm pool-and-split study was carried out using buffy coat-derived PLTs stored in 30% plasma/70% SSP+.

Formation of Polyrotaxane Particles via Template Assembly.

In this study, we report a versatile method to assemble tunable poly(ethylene glycol) (PEG)-based polyrotaxane (PRX) particles and capsules. By threading α-cyclodextrins (αCDs) onto PEG chains physically adsorbed onto template particles and subsequently dissolving the templates, PRX replica particles and hollow capsules are formed. This approach overcomes issues related to CD steric hindrance, and also reduces the multiple processing steps often associated with PRX-based particle formation.

Engineering tough, highly compressible, biodegradable hydrogels by tuning the network architecture.

By precisely tuning the network architecture, tough, highly compressible hydrogels were engineered. The hydrogels were made by interconnecting high-functionality hydrophobic domains through linear tri-block chains, consisting of soft hydrophilic middle blocks, flanked with flexible hydrophobic blocks. In showing their applicability, the efficient encapsulation and prolonged release of hydrophobic drugs were achieved.

Nanoparticles assembled via pH-responsive reversible segregation of cyclodextrins in polyrotaxanes.

Supramolecular polymers with monomers bound together by secondary interactions, such as polyrotaxanes (PRXs), consisting of alpha cyclodextrin (αCD) threaded onto poly(ethylene glycol) (PEG), have attracted interest as a result of their ability to overcome physical limitations present in conventional, covalently structured polymers. Herein, we describe the formation of pH-responsive supramolecular assemblies from carboxyethylester bearing αCD and PEG PRXs. These PRXs were formed using PEG of Mw 20 kDa and a threading degree of 28%.

In vitro Quality of Platelets with Low Plasma Carryover Treated with Ultraviolet C Light for Pathogen Inactivation.

Background: The THERAFLEX UV-Platelets system uses shortwave ultraviolet C light (UVC, 254 nm) to inactivate pathogens in platelet components. Plasma carryover influences pathogen inactivation and platelet quality following treatment. The plasma carryover in the standard platelets produced by our institution are below the intended specification (<30%).

Refrigeration and cryopreservation of platelets differentially affect platelet metabolism and function: a comparison with conventional platelet storage conditions.

Background: Alternatives to room temperature storage of platelets (PLTs) may be beneficial to extend the limited shelf life and support transfusion logistics in rural and military areas. The aim of this study was to assess the morphologic, metabolic, and functional aspects of PLTs stored at room temperature or in refrigerated conditions or cryopreserved.

Study Design And Methods: A three-arm pool-and-split study was carried out using buffy coat-derived PLTs stored in 30% plasma/70% SSP+.

A novel solid state photocatalyst for living radical polymerization under UV irradiation.

This study presents the development of a novel solid state photocatalyst for the photoinduced controlled radical polymerization of methacrylates under mild UV irradiation (λmax ≈ 365 nm) in the absence of conventional photoinitiators, metal-catalysts or dye sensitizers. The photocatalyst design was based on our previous finding that organic amines can act in a synergistic photochemical reaction with thiocarbonylthio compounds to afford well controlled polymethacrylates under UV irradiation. Therefore, in the current contribution an amine-rich polymer was covalently grafted onto a solid substrate, thus creating a heterogeneous catalyst that would allow for facile removal, recovery and recyclability when employed for such photopolymerization reactions.

Photocontrolled Cargo Release from Dual Cross-Linked Polymer Particles.

Burst release of a payload from polymeric particles upon photoirradiation was engineered by altering the cross-linking density. This was achieved via a dual cross-linking concept whereby noncovalent cross-linking was provided by cyclodextrin host-guest interactions, and irreversible covalent cross-linking was mediated by continuous assembly of polymers (CAP). The dual cross-linked particles (DCPs) were efficiently infiltrated (∼80-93%) by the biomacromolecule dextran (molecular weight up to 500 kDa) to provide high loadings (70-75%).

Extended storage and glucose exhaustion are associated with apoptotic changes in platelets stored in additive solution.

Background: The storage of platelets (PLTs) in additive solution (AS) may facilitate improved PLT quality and possibly extension of the PLT shelf life. A minimum amount of plasma is required when PLTs are stored in AS, as a source of glucose. The aim of this study was to assess the effect of reducing the plasma carryover to 20% on PLT quality when stored in SSP+ for an extended period.

Fabrication of ultra-thin polyrotaxane-based films via solid-state continuous assembly of polymers.

Surface-confined ultra-thin polyrotaxane (PRX)-based films with tunable composition, surface topology and swelling characteristics were prepared by solid-state continuous assembly of polymers (ssCAP). The PRX-based films supported cell attachment, and their degradation in biological media could be tuned. This study provides a versatile nano-coating technology with potential applications in biomedicine, including tissue engineering and medical devices.

In vitro comparison of cryopreserved and liquid platelets: potential clinical implications.

Background: Platelet (PLT) concentrates can be cryopreserved in dimethyl sulfoxide (DMSO) and stored at -80°C for 2 years. These storage conditions improve availability in both rural and military environments. Previous phenotypic and in vitro studies of cryopreserved PLTs are limited by comparison to fresh liquid-stored PLTs, rather than PLTs stored over their clinically relevant shelf life.

Cyclodextrin-based supramolecular assemblies and hydrogels: recent advances and future perspectives.

The application of cyclodextrin (CD)-based host-guest interactions towards the fabrication of functional supramolecular assemblies and hydrogels is of particular interest in the field of biomedicine. However, as of late they have found new applications as advanced functional materials (e.g.

PAS-G supports platelet reconstitution after cryopreservation in the absence of plasma.

Background: Platelet (PLT) concentrates frozen in dimethyl sulfoxide (DMSO) can be stored for extended periods at -80°C. PLTs are frozen in a hyperconcentrated state to avoid postthaw washing and minimize residual DMSO. Consequently, PLTs require reconstitution upon thawing.

Synthesis of Novel Core Cross-Linked Star-Based Polyrotaxane End-Capped via "CuAAC" Click Chemistry.

The first example of core cross-linked star (CCS) polyrotaxane was prepared using the poly(ϵ-caprolactone) (PCL) CCS three-dimensional (3D) scaffold. The 3D CCS polymer was firstly prepared through the "arm-first" approach. Then, the "arms" of the resultant PCL CCS polymer were threaded with α-cyclodextrins (α-CDs).