Blood Protein Adsorption Research Articles

Long in vivo circulating nanomicelles formed by sharp-contrast Janus star polymers derived from β-cyclodextrin grafted with lipids and polyzwitterions

Amphiphilic block polymers have the ability to self-assemble and form nanomicelles, which have been extensively studied as nanocarriers for improving the bioavailability and biodistribution of chemotherapeutic drugs while reducing systemic toxicity. However, polymer micelles often face issues with poor stability in the bloodstream, leading to a short circulation time and leakage of the payload. Here, this work reports a rational design of a sharp-contrast Janus star polymer (SJSP) consisting of multiple arms of superhydrophobic lipid moieties and superhydrophilic polyzwitterion chains attached to a β-cyclodextrin core. The SJSP polymer forms nanomicelles possessing a stable core and a controllable and dense stealth shell that effectively protects them in the bloodstream, preventing payload leakage and blood protein adsorption. It is demonstrated that the hydrophobic/hydrophilic balance can be optimized to achieve strong micellar assembly by adjusting the number of lipid and polyzwitterion arms. The SJSP micelle system shows significantly longer blood circulation time in vivo compared to linear counterparts and other available amphiphilic block copolymer micelle systems. Therefore, the SJSP micelle design offers a promising strategy for developing nanocarriers with potential for translational applications in vivo.

On-demand bactericidal and self-adaptive antifouling hydrogels for self-healing and lubricant coatings of catheters

Catheter-related infections are one of the most common nosocomial infections with increasing morbidity and mortality, and robust antibacterial or antifouling catheter coatings remain great challenges for long-term implantation. Herein, multifunctional hydrogel coatings were developed to provide persistent and self-adaptive antifouling and antibacterial effects with self-healing and lubricant capabilities. Polyvinyl alcohol (PVA) with β-cyclodextrin (β-CD) grafts (PVA-Cd) and 4-arm polyethylene glycol (PEG) with adamantane and quaternary ammonium compound (QAC) terminals (QA-PEG-Ad) were crosslinked through host-guest recognitions between adamantane and β-CD moieties to acquire PVEQ coatings. In response to bacterial infections, QACs exhibit reversible transformation between zwitterions (pH 7.4) and cationic lactones (pH 5.5) to generate on-demand bactericidal effect. Highly hydrophilic PEG/PVA backbones and zwitterionic QACs build a lubricate surface and decrease the friction coefficient 10 times compared with that of bare catheters. The antifouling hydrated layer significantly inhibits blood protein adsorption and platelet activation and reveals negligible hemolysis and cytotoxicity. The dynamic host-guest crosslinking achieves full self-healing of cracks in PVEQ hydrogels, and the mechanical profiles were recovered to over 90 % after rejuvenating the broken hydrogels, exhibiting a long-term stability after mechanical stretching, twisting, knotting and compression. After subcutaneous implantation and local bacterial infection, the retrieved PVEQ-coated catheters display no tissue adhesion and 3 log folds lower bacterial number than that of bare catheters. PVEQ coatings effectively prevent the repeated bacterial infections and there are few inflammatory reactions in the surrounding tissue, while substantial lymphoid infiltration and inflammatory cell aggregation occur in muscle tissues around the bare catheter. Thus, this study demonstrates a catheter coating strategy by on-demand bactericidal, self-adaptive antifouling, self-healing and lubricant hydrogels to address medical devices-related infections. Statement of significanceIt is estimated over two billion peripheral intravenous catheters are annually used in hospitals around the world, and catheter-associated infection has become a great clinical challenge with rapidly rising morbidity and mortality. Surface coating is considered a promising approach, but substantial challenges remain in the development of coatings that simultaneously satisfy both anti-fouling and antibacterial attributes. Even more, few attempts have been made to design mechanically robust coatings and reversible antibacterial or antifouling capabilities, which are critical for long-term medical implants. To address these challenges, we propose a concise strategy to develop hydrogel coatings from commercially available poly(ethylene glycol) and polyvinyl alcohol. In addition to self-healing and lubricant capabilities, the reversible conversion between zwitterionic and cationic lactones of quaternary ammonium compounds enables on-demand bactericidal and self-adaptive antifouling effects.

Hydrophilic modified PES asymmetric membrane via thermal cross-linking for artificial lung application

Excellent hemocompatibility and long-term stability against blood wetting are important properties required for artificial lung membrane, the core component in extracorporeal membrane oxygenator which is life-saving for patients with severe lung dysfunctions. Herein, novel hydrophilic modified polyethersulfone (PES) asymmetric membranes were synthesized via thermal cross-linking, and characterization via SEM, FTIR, 1H NMR and surface water contact angle measurements demonstrated that the modified asymmetric membranes composing a dense layer with hydrophilic surface on top of a microporous support layer were successfully fabricated without any observed defects. Among all the modified membranes, PEGylated PES membrane exhibited the smoothest membrane surface, improved mechanical property, good gas permeability and the best performance in hemocompatibility in terms of blood coagulation, protein adsorption and platelet adhesion. Moreover, the PEGylated PES membrane showed excellent long-term stability in membrane surface wettability as well as long-term stable performance against blood fouling and wetting. This research work provides valuable insights and new idea into synthesizing membranes, with simple synthesis process, long lasting high hemocompatibility and stability against wetting, for application as artificial lung membranes.

Fabrication and characterization of TiO2‐hydroxyapatite composite‐loaded Polysulfone membranes with integrated biocompatibility for dialysis application

AbstractBackgroundThe use of Polysulfone (PSf) as membrane material for dialysis therapy is becoming more common. However, the PSf membrane can cause the adsorption of blood proteins followed by the adhesion of platelets, destruction of red blood cells, and thrombus formation. One of the biggest challenges in creating membranes for hemodialysis (HD) applications is ensuring biocompatibility. Therefore, to maintain the biocompatibility of PSf membranes, further modifications are necessary.MethodsIn this study, the performance and biocompatibility of PSf membranes were improved by the impregnation of TiO2‐hydroxyapatite composite as an additive. The TiO2‐hydroxyapatite composite was first synthesized via sintering at 1200°C, and then a dope solution composed of pristine PSf polymer solution in N‐Methyl‐2‐pyrrolidone solvent (NMP) and different wt% ratios of the synthesized composite were prepared, and resultant membranes were fabricated using a film applicator via a phase inversion scheme using water as a non‐solvent exchange medium. The synthesized composite was characterized using SEM, EDX, and XRD techniques.ResultsThe FTIR analysis confirmed the weak interaction of PSf polymer with the hydroxyapatite moiety of the composite. The interaction of the synthesized composite within the membrane matrix was evaluated via leaching ratio results. The hydrophilicity, pore profile, and pure water permeation flux rates were also determined. The results of the biocompatibility study showed that membranes based on TiO2‐hydroxyapatite composite had reduced adsorption of BSA protein by 34.41% as well as less than 5% hemolysis ratio. Additionally, the study displayed thrombus formation ranging from 2.08% to 8.69%, respectively. The dialysis results indicated that compared with the original PSf membrane, the TiO2‐hydroxyapatite composite showed high clearance rates for urea (73.81%) and creatinine (72.13%) solutes, respectively.ConclusionTherefore, blending TiO2‐hydroxyapatite composite in the PSf membrane significantly improved the biocompatibility and removal ability of uremic solutes.

Immobilization of novel synthesized phosphobetaine zwitterions on polyethersulphone (PES) hemodialysis membranes to induce hemocompatibility: Experimental, molecular docking, and ex-vivo inflammatory biomarker investigations

Hemodialysis therapy is a crucial life-saving treatment for severe kidney conditions, particularly in cases where organ transplantation is limited. However, the use of polymeric membranes in clinical dialyzers can trigger undesirable reactions in the blood, such as complement, leukocyte, and coagulation activations. These reactions can lead to hypertension, cardiovascular diseases, and even death, due to compatibility issues. This paper presents a study on the development and application of a novel phosphobetaine zwitterion, immobilized on polyethersulphone (PES) clinical hemodialysis membranes, to improve hemocompatibility. The study also introduces a new method for immobilizing a zwitterionic PVP-phosphobetaine polymer on a PES membrane, using a polydopamine (PDA) crosslinker. The synthesized membranes were characterized, and their performance in terms of blood-protein adsorption and subsequent interaction, specifically with fibrinogen, was investigated to evaluate hemocompatibility. The selection of the phosphobetaine polymer was driven by its capacity to form an electrically neutral zwitterionic hydration layer, which serves as a protective barrier, preventing fibrinogen adsorption. Without this zwitterionic polymer, blood proteins interact with the bare membrane, initiating biological processes that lead to inflammation when exposed to uremic blood. Molecular docking studies were conducted to understand the interactions between various ligands and specific serum protein components. The phosphate and carbonyl chemical groups on the pyrrolidinone zwitterionic moiety were found to form polar interactions with specific amino acids. Exvivo investigations involving incubated coated membranes and uremic blood samples from end-stage renal disease (ESRD) patients revealed that they caused weaker complement and coagulation activation compared to bare PES membranes. In addition, the inflammatory biomarkers have been studied to shed light on their potential impact on patients' quality of life. This study contributes to our understanding of the implications of blood-protein fouling and the hemocompatibility challenges faced by blood-contacting devices used in hemodialysis for ESRD patients, who are prone to membrane-related health complications.

Polyvinylpyrrolidone-stabilised gold nanoparticle coatings inhibit blood protein adsorption

Abstract In this work, the ability of polyvinylpyrrolidone (PVP)-stabilised gold nanoparticle (AuNP) coatings to inhibit blood protein adsorption was evaluated by studying time-resolved solid–liquid interactions of the coatings with the model blood protein bovine serum albumin (BSA). Inhibiting unspecific blood protein adsorption is of crucial importance for blood-contacting implant devices, e.g. vascular grafts, stents, artificial joints, and others, as a preventive strategy for bacterial biofilm formation. A quartz crystal microbalance was used in this work to coat the AuNPs on piezoelectric sensors and to follow time-resolved solid–liquid interactions with the proteins. The AuNP coatings were evaluated for their wettability by contact angle measurements, their surface morphology by light- and atomic force microscopy, and their chemical composition by energy-dispersive X-ray spectroscopy. Results revealed a homogeneous distribution of AuNPs on the sensor surface with a dry mass coverage of 3.37 ± 1.46 µg/cm2 and a contact angle of 25.2 ± 1.1°. Solid–liquid interaction studies by quartz crystal microbalance showed a high repellence of BSA from the PVP-stabilised AuNP coatings and the importance of the PVP in the mechanism of repellence. Furthermore, the conformation of the polymer on the coatings as well as its viscoelastic properties were revealed. Finally, the activated partial thrombin time test and fibrinogen adsorption studies revealed that the AuNPs do not accelerate blood coagulation and can partially inhibit the adhesion of fibrinogen, which is a crucial factor in the common blood coagulation cascade. Such AuNPs have the potential to be used in blood-contact medical applications.

Physicochemical characterization, biodistribution, and bio‐effects of fluorescent carbon dots from roasted Spanish mackerel

AbstractNanoparticles with small sizes formed in the process of food thermal treatment have gained substantial attention due to their safety uncertainty and latent risks to human health. Herein, the physicochemical features of fluorescent carbon dots (CDs) from roasted Spanish mackerel were studied, it was found that the size distribution, fluorescence properties, surface groups, and formation process of CDs were highly dependent on the roasting time of Spanish mackerel. The interaction of CDs with digestive proteases resulted in the structural change and activity inhibition of proteases. When the concentration of CDs was 120 μg mL−1, the enzyme activity of pepsin and trypsin was reduced from 100% to 75.95% and 78.5%, respectively. The CDs caused static fluorescence quenching of pepsin and trypsin as confirmed by the fluorescence analysis. After oral administration, CDs can be transported to the main organs through the blood. The cytotoxicity assessment revealed that the cell viability decreased with the prolonging of roasting time. The CDs roasted at 230°C for 40 min showed a significant hemolytic effect even at a low concentration of 0.5 mg mL−1. Moreover, the cellular uptake level and pathway of CDs were significantly affected by blood protein adsorption. This study helps to evaluate the in vivo biodistribution, the interaction with proteases during gastrointestinal digestion, and the cellular uptake of CDs after transport through the blood, providing a theoretical basis for revealing the potential effects of foodborne nanoparticles.

Preparation of Hyflon AD/Polypropylene Blend Membrane for Artificial Lung.

A high-performance polypropylene hollow fiber membrane (PP-HFM) was prepared by using a binary environmentally friendly solvent of polypropylene as the raw material, adopting the thermally induced phase separation (TIPS) method, and adjusting the raw material ratio. The binary diluents were soybean oil (SO) and acetyl tributyl citrate (ATBC). The suitable SO/ATBC ratio of 7/3 was based on the size change of the L-L phase separation region in PP-SO/ATBC thermodynamic phase diagram. Through the characterization and comparison of the basic performance of PP-HFMs, it was found that with the increase of the diluent content in the raw materials, the micropores of outer surface of the PP-HFM became larger, and the cross section showed a sponge-like pore structure. The fluoropolymer, Hyflon ADx, was deposited on the outer surface of the hollow fiber membrane using a physical modification method of solution dipping. After modification, the surface pore size of the Hyflon AD40L modified membranes decreased; the contact angle increased to around 107°; the surface energy decreased to 17 mN·m-1; and the surface roughness decreased to 17 nm. Hyflon AD40L/PP-HFMs also had more water resistance properties from the variation of wetting curve. For biocompatibility of the membrane, the adsorption capacity of the modified PP membrane for albumin decreased from approximately 1.2 mg·cm-2 to 1.0 mg·cm-2, and the adsorption of platelets decreased under fluorescence microscopy. The decrease in blood cells and protein adsorption in the blood prolonged the clotting time. In addition, the hemolysis rate of modified PP membrane was reduced to within the standard of 5%, and the cell survival rate of its precipitate was above 100%, which also indicated the excellent biocompatibility of fluoropolymer modified membrane. The improvement of hydrophobicity and blood compatibility makes Hyflon AD/PP-HFMs have the potential for application in membrane oxygenators.

Biological and mechanical evaluation of cinnamaldehyde doped liquid crystal-polymer composite membranes

In this study cinnamaldehyde (CA) doped polyurethane cholesteryl pelargonate cholesteric liquid crystal composite membranes were produced and their properties were examined for use in biological applications. The relationship between the blood coagulation and protein adsorption was studied and the results showed that increasing CA concentration allowed an improvement in biological properties of them. Additionally, the effect of CA on the hyrophobicity of these membranes was investigated by determining water holding capacity, contact angles. The mechanical strength of these membranes were determined and it was found that their strength increased and the ability to elongate decreased with an increasing CA dopant concentration.

Nonwoven Hemostatic Dressings Formed by Contact Drawing of Interposed Polyethylene Oxide (PEO)‐Fibrinogen and PEO‐Thrombin Microfibers

AbstractTextiles containing interposed layers of polyethylene oxide (PEO)‐fibrinogen and PEO‐thrombin fibers are explored as biomaterials for hemostasis. The PEO‐fibrinogen and PEO‐thrombin fibers are formed by contact drawing, an approach that uses an entangled polymer solution and a pin array to form fibers by extension of liquid bridges. The interposition of the PEO‐fibrinogen and PEO‐thrombin fibers results in polymerization of a fibrin hydrogel mesh once the textile is hydrated. This fibrin hydrogel mesh displays the expected bands and diffraction peaks by Fourier‐transform infrared spectromicroscopy and X‐ray diffraction, respectively. The functionality of the hemostatic textiles formed from the interposed PEO‐fibrinogen and PEO‐thrombin fibers is demonstrated by analyzing human blood hemolysis, complement activation, protein adsorption, and platelet and leukocyte adhesion, indicating compatibility with human blood (hemolysis ratio <5%), with minimal inflammatory response (levels of terminal complement complex equivalent to plasma). The cytocompatibility and potential for cell remodeling of the fibrin hydrogel mesh formed by this process is evaluated with human dermal fibroblasts and human keratinocytes and it is found that both cell types attach and grow on the fibrin mesh. Finally, a whole blood clotting time of less than 30 s suggests a potential use of this material in hemorrhage control.

Dual-phase nanoplasmonic sensing platform for monitoring blood protein adsorption and its coagulation in vitro

Protein adsorption onto solid surfaces is an immanent and spontaneous phenomenon that occurs in many fundamental biomedical applications. Recent research mainly focuses on collectively measuring the protein behaviors in confined localized nanosensing areas, whereas ignoring the ambient aqueous variation that directly affects protein behavior, such as the hydrogen bonding network in protein-water which serves as a crucial and mutually constrained environment. Herein, we develop a novel dual-phase plasmonic sensing platform with a gold nanopyramid array (GNPA), simultaneously monitoring protein binding at the nanosensing surface and the variation tendency of hydrogen bonding in aqueous solution. Two types of protein adsorption and their solution variation are explored: we first investigate bovine serum albumin (BSA) adsorption and its variation tendency of hydrogen bonding formation and fracture in water. Then we apply the sensing chip to monitor the fibrinogen adsorption and its real-time conversion to fibrin in an in vitro model of simulated blood coagulation, where the synchronous sensing signals of localized surface plasmon resonance (LSPR) and aqueous hydrogen bonding variations are acquired. It helps to reveal the connection between hydrogen bonding variations in protein-water solution and protein adsorption behaviors at the surface, a meaningful finding for comprehending the initiation of abnormal blood coagulation and the related thromboembolism disease. Moreover, the proposed dual-phase sensing strategy opens a new path for a wider variety of applications, ranging from monitoring microenvironmental changes inside the human body to detecting the water contamination or environmental pollutants.

Human serum albumin adsorption on cellulose nanocrystal: A spectroscopy and molecular dynamics simulation research

Cellulose nanocrystal (CNC) is a relatively new natural nanoparticle derived from plants. Several biomedical applications are envisioned for CNC. Although its safety upon systemic administration is still questionable, it may serve as a worthy substrate for the adsorption of blood proteins in ex vivo settings for diagnostic purposes. The interaction between CNC and Human serum albumin (HSA) may influence both structure and function of other adsorbed proteins on the CNC surface. Herein, molecular dynamics (MD) simulation and circular dichroism spectroscopy (CD) were utilized to study the conformational changes of HSA in the presence and absence of the CNC. The secondary structure study results show that the HSA structure was conserved during the interaction. Fluorescence spectroscopy indicates that the CNC has a quenching property on the intrinsic fluorescence of HSA. Furthermore, increasing CNC concentrations led to a blue shift in the HSA fluorescence emission at 344 nm. The Gibbs free energy demonstrated the HSA and CNC interaction is spontaneous; the MMPBSA outcomes also approved that electrostatic and van der Waals (vdW) interactions were the major forces in the HSA-CNC complex. The results of this study shed light on the adsorption of HSA on CNC and the nature of their interactions.

Polyaspartic acid, 2-acrylamido-2-Methyl propane sulfonic acid and sodium alginate based biocompatible stimuli responsive polymer gel for controlled release of GHK-Cu peptide for wound healing.

Stimuli responsive polymer based on Polyaspartic acid, 2-Acrylamido-2-methylpropane sulfonic acid and sodium alginate (NaAlg) were synthesized using two cross-linkers Ethylene glycol dimethacrylate (EGDMA) and TMPTA (Trimethylolpropane triacrylate). The polymers were standardized and optimized to obtain a polymer with maximum swelling in distilled water, saline, glucose and solutions of varying pH. The synthesized polymer swelled well in distilled water, glucose solution and acidic- alkaline medium. The biocompatibility of the polymer was evaluated for blood compatibility and protein adsorption. The polymer with maximum swelling property was used for peptide release studies. The polymer was further used to study the peptide encapsulation and release efficiency of the polymeric material which was confirmed by FTIR, Scanning Emission Microscope and EDX. The encapsulation efficiency of the polymer for encapsulating (glycyl-l-histidyl-l-lysine-copper) GHK-Cu was observed to be 55.26% and peptide release of 51.84% was observed for Ethylene glycol dimethacrylate based polymer after 24h whereas for Trimethylolpropane triacrylate based polymer the encapsulation efficiency was observed to be 49.6% and release was 39.01%. The EGDMA based polymer was further examined under in vivo studies in order to evaluate the efficiency of the synthesized polymer. The in vivo studies include wound closure, histopathological analysis, biochemical and toxicity assay. The material has shown promising results for both in vivo and in vitro studies.

Characterization of the foreign body response of titanium implants modified with polyphenolic coatings.

The foreign body response is dictating the outcome of wound healing around any implanted materials. Patients who suffer from chronic inflammatory diseases and impaired wound healing often face a higher risk for implant failure. Therefore, functional surfaces need to be developed to improve tissue integration. For this purpose, we evaluated the impact of surface coatings made of antioxidant polyphenolic molecules tannic acid (TA) and pyrogallol (PG) on the host response in human blood. Our results showed that although the polyphenolic surface modifications impact the initial blood protein adsorption compared to Ti, the complement and coagulation systems are triggered. Despite complement activation, monocytes and granulocytes remained inactivated, which was manifested in a low pro‐inflammatory cytokine expression. Under oxidative stress, both coatings were able to reduce intracellular reactive oxygen species in human gingival fibroblasts (hGFs). However, no anti‐inflammatory effects of polyphenolic coatings could be verified in hGFs stimulated with lipopolysaccharide and IL‐1β. Although polyphenols reportedly inhibit the NF‐κB signaling pathway, phosphorylation of NF‐κB p65 was observed. In conclusion, our results indicated that TA and PG coatings improved the hemocompatibility of titanium surfaces and have the potential to reduce oxidative stress during wound healing.

Dual-Phase Nanoplasmonic Sensing Platform for Monitoring Blood Protein Adsorption and its Coagulation in Vitro

Dual-Phase Nanoplasmonic Sensing Platform for Monitoring Blood Protein Adsorption and its Coagulation in Vitro

Reduced thrombogenicity of surface-treated Nitinol implants steered by altered protein adsorption

Blood-contacting medical implants made of Nitinol and other titanium alloys, such as neurovascular flow diverters and peripheral stents, have the disadvantage of being highly thrombogenic. This makes the use of systemic (dual) anti-platelet/anticoagulant therapies inevitable with related risks of device thrombosis, bleeding and other complications. Meeting the urgent clinical demand for a less thrombogenic Nitinol surface, we describe here a simple treatment of standard, commercially available Nitinol that renders its surface ultra-hydrophilic and functionalized with phosphate ions. The efficacy of this treatment was assessed by comparing standard and surface-treated Nitinol disks and braids, equivalent to flow diverters. Static and dynamic (Chandler loop) blood incubation tests showed a drastic reduction of thrombus formation on treated devices. Surface chemistry and proteomic analysis indicated a key role of phosphate and calcium ions in steering blood protein adsorption and avoiding coagulation cascade activation and platelet adhesion. A good endothelialization of the surface confirmed the biocompatibility of the treated surface. STATEMENT OF SIGNIFICANCE: Titanium alloys such as Nitinol are biocompatible and show favorable mechanical properties, which led to their widespread use in medical implants. However, in contact with blood their surface triggers the activation of the intrinsic coagulation cascade, which may result in catastrophic thrombotic events. The presented results showed that a phosphate functionalization of the titanium oxide surface suppresses the activation of both coagulation cascade and platelets, avoiding the subsequent formation of a blood clot. This novel approach has therefore a great potential for mitigating the risks associated to either thrombosis or bleeding complications (due to systemic anticoagulation) in patients with cardiovascular implants.

Abstract P-35: Cryo-Electron Tomography of Protein Conjugated Upconverting Nanophosphors

Background: Over the past decades, significant advances have been made in the field of creating nanobioreagents for solving modern medicine problems (Grebenik et al., JBO, 2013). However, the problem of their low accumulation rate in pathological tissue in vivo experiments still remains. First of all, it is associated with the adsorption of blood proteins on the surface of nanobioreagents and the protein layer formation, which significantly changes the surface properties, which leads to their rapid excretion by the reticuloendothelial system. In particular, it is possible to reduce the blood plasma proteins adsorption and increase the time spent in the circulatory system by forming a coating of proteins. Methods: In situ cryоelectron tomography (Cryo-ET) is the only method that allows the experimental observation of protein structures on the nanoparticle’s surface in their natural functional state. The basic principle of the method is to obtain a series of projections of a vitrified sample thin lamella at different tilt angles related to an incident electron beam. Their further processing leads to obtaining the volumetric information about the structure of the sample. The use of a cryo-focused ion beam (Cryo-FIB) in specimen thinning makes it possible to carry out experiments with thin sections of cellular structures and observe the penetration of nanoparticles into the intracellular environment. Results: Upconverting nanophosphors (AN) were used as a nanoplatform for creating a protein coating. To create a protein coating on the AN surface, they were functionalized using an amphiphilic polymer containing carboxyl groups. Then, conjugation with protein molecules from the class of immunoglobulins was carried out by the method of carbodiimide activation. At each stage of synthesis and modification, AN solutions with different size distribution were vitrified for subsequent tomography. After a series of experiments to study the morphology of nanoparticles, an experiment on their successful absorption by cells of the cancer line A549 was carried out. Conclusion: Within this work, a series of in situ Cryo-ET methods were proposed and applied for structural characterization and visualization of the processes of synthesis, modification, and engulfment of nanoparticles into cellular systems. For the first time in its native form, the engulfment of ANF into the internal environment of the A549 cancer line cells was demonstrated.

Characterization of blood protein adsorption on PM2.5 and its implications on cellular uptake and cytotoxicity of PM2.5

In biological fluids, micro- or nano-size particles are prone to adsorb proteins and form a layer. The ambient air fine particulate matter (PM2.5) is inhaled via the lung, penetrates biological barriers and eventually reaches systemic blood circulation. However, there are very few data available regarding the adsorption of proteins on PM2.5. Here, we compared protein corona formed in plasma after bronchoalveolar lavage fluid (BALF) exposure with those formed in plasma alone. Using purified coronal proteins, we explored their adsorption behaviors on PM2.5 and their influence on biological reactivity of PM2.5. Liquid-chromatography tandem mass-spectrometry (LC-MS/MS) analysis revealed that exposure to BALF significantly changed the blood protein profile on PM2.5. Regardless of the presence of BALF, the protein corona on PM2.5 contained an abundance of serum albumin, hemoglobin (Hb) and fibrinogen (Fg) proteins. Using Fg as a corona surrogate, we found that van der Waals interactions, hydrophobic interactions, π-π stacking and electrostatic attractions contributed to the Fg adsorption and led to the conformational changes of Fg. In addition, Fg decoration decreased cellular internalization of PM2.5 and corresponding subsequent oxidative stress responses in a murine RAW264.7 macrophage. These results support the view that the formation of PM2.5 corona should be considered for toxicity assessment of PM2.5.

Sung Wan Kim - Early events in blood/material interactions

Sung Wan Kim's initial efforts as an independent investigator were focused on improving the understanding of the early events in blood/material interactions with the goal to develop blood compatible materials for application in medical devices and prostheses. These initial efforts were centered around blood protein adsorption on biomaterials and related mechanisms of thrombus formation (thrombosis). Ultimately, Sung Wan's efforts were expanded to studies of the non-thrombogenic nature of heparinized biomaterials, prostaglandin biomaterials, and block copolymer systems. These studies were supported by two NIH grants for 22 and 19 years, respectively, and a NIH Career Development Award. Moreover, these studies resulted in over 140 peer-reviewed publications and training of many students and postdoctoral scientists. The intent of this paper is to identify key concepts, papers, and contributions by Sung Wan and his colleagues that fall within the four aforementioned research categories. In this context, many of Sung Wan's early efforts contributed directly to Utah's biomaterials efforts and the Total Artificial Heart program at the time, while providing the foundation for the productive international Triangle Collaboration as well as his following work in polymer-controlled drug releasing systems.

Photoreactive Carboxybetaine Copolymers Impart Biocompatibility and Inhibit Plasticizer Leaching on Polyvinyl Chloride.

Protein and cell interactions on implanted, blood-contacting medical device surfaces can lead to adverse biological reactions. Medical-grade poly(vinyl chloride) (PVC) materials have been used for decades, particularly as blood-contacting tubes and containers. However, there are numerous concerns with their performance including platelet activation, complement activation, and thrombin generation and also leaching of plasticizers, particularly in clinical applications. Here, we report a surface modification method that can dramatically prevent blood protein adsorption, human platelet activation, and complement activation on commercial medical-grade PVC materials under various test conditions. The surface modification can be accomplished through simple dip-coating followed by light illumination utilizing biocompatible polymers comprising zwitterionic carboxybetaine (CB) moieties and photosensitive cross-linking moieties. This surface treatment can be manufactured routinely at small or large scales and can impart to commercial PVC materials superhydrophilicity and nonfouling capability. Furthermore, the polymer effectively prevented leaching of plasticizers out from commercial medical-grade PVC materials. This coating technique is readily applicable to many other polymers and medical devices requiring surfaces that will enhance performance in clinical settings.