Biomedical subjects

C Vigneron

Publications and source records attributed to C Vigneron.

At least 19 recordsLinked to original sources

PubMed2003

Physicochemical evaluation of PLA nanoparticles stabilized by water-soluble MPEO-PLA block copolymers.

Different water-soluble MPEO-PLA diblock copolymers with various alpha-methoxy-omega-hydroxyl polyethylene (MPEO) and poly(lactic acid) (PLA) block lengths have been synthesized. Their surface-active properties were evidenced by surface tension (water/air) measurements. In each case the surface tension leveled down above a critical polymer concentration, which was attributed to the formation of a dense polymer layer at the liquid-air interface. The applicability of copolymers as emulsion stabilizers in the preparation of PLA nanospheres by an o/w emulsion/evaporation technique was then investigated. Four copolymers presenting sufficient water solubility and good surfactive properties were used to prepare PLA nanospheres with MPEO chains firmly anchored at the particle surface. The effect of polymer concentration in emulsion on particle size and surface coverage was examined. Whatever the copolymer characteristics, it was found that the optimal concentration to obtain a large amount of MPEO at the particle surface was similar (around 2 g/l). The effect of the copolymer composition on MPEO layer characteristics and on colloidal stability was also evaluated. The conformation of MPEO blocks at the PLA particle surface is discussed in relation to the layer thickness and the surface area occupied per molecule.

Journal Article↗

PubMed2003

Biological response of human aortic endothelial cells exposed to acellular hemoglobin solutions developed as potential blood substitutes.

The cardiovascular effects of hemoglobin-based oxygen carriers (HBOCs) are mainly related to their nitric oxide (NO) scavenging properties but other effects such as the impact of these hemoglobins on the endothelial cell (EC) biology are not well understood. We hypothesized that HBOCs could modify EC functions by altering gene expression, in particular the endothelial NO synthase (NOS3) and/or by activating EC. Cultured human aortic endothelial cells (HAEC) were incubated for 3 hours with purified cell-free Hb, Dex-BTC-Hb or alpha alpha-Hb (16 g/L). Expression of NOS3 mRNA and protein were assessed by semi-quantitative RT-PCR and Western blot respectively immediately after and 24 hours after incubation. The expression and localization of the adhesion molecule ICAM-1 were detected by fluorescence microscopy. None of the solutions tested modified NOS3 mRNA and protein expression despite adequate controls that up- or down-regulate NOS3 expression. The expression and the localization of ICAM-1 on the cell membrane were modified after 3 hours of incubation with all the hemoglobin solutions tested in a manner similar to tumor necrosis factor-alpha. In conclusion, HAEC incubation with clinically relevant concentrations of HBOCs induced changes in the pattern of ICAM-1 expression consistent with cell activation/cell signaling mechanisms. However, HBOCs did not alter NOS3 gene expression.

Aorta↗

PubMed2003

Effect of roscovitine, a cdk1 inhibitor, and of the presence of oocyte on bovine cumulus cell expansion and cyclooxygenase-2 expression.

Oocyte maturation is accompanied by differentiation of surrounding cumulus cells. These cells produce hyaluronic acid (HA) and its storage in intercellular spaces results in expansion of the cells. The cumulus cells also accumulate cyclooxygenase-2 (cox-2) during maturation. Both expansion and cox-2 storage are regulated by FSH and EGF. The aim of this study was to determine whether oocyte meiotic resumption is involved in the regulation of cumulus differentiation or not. We investigated the effects of roscovitine, a reversible inhibitor of meiosis resumption of cattle oocytes on EGF induced expansion and cox-2 expression at the transcript and protein levels respectively (RT-PCR and Western blot), in cumulus oocyte complexes (COCs) and cumulus complexes alone (CCs). EGF induced expansion and cox-2 expression in both COCs and CCs. These effects were prevented by roscovitine, whether in the presence or in the absence of oocyte. However, the oocyte was essential for the reversibility of inhibition by roscovitine. In conclusion, our results indicate that i) oocyte secreted-factors are not essential for cumulus expansion, and ii) roscovitine mediated inhibition of meiotic resumption also respects the functionality of the surrounding somatic cells.

Animals↗

PubMed2002

Effect of follicular size on meiotic and developmental competence of porcine oocytes.

In several species, the developmental competence of the oocyte is acquired progressively during late follicular growth, after the acquisition of the competence to resume and complete meiosis. In the pig, full meiotic competence of the oocyte is reached in ovarian follicles with a diameter of 3 mm or more. However, there is no information about developmental competence acquisition. We analyzed the ability of oocytes from three foll icular size classes to resume and complete meiosis, to be fertilized, and to develop in vitro to the blastocyst stage. A total of 941 follicles were dissected from slaughterhouse gilt ovaries and classified as small (<3 mm, n = 330), medium (3-5 mm, n = 373), or large (>5 mm, n = 238). The cumulus-oocyte complexes recovered from these follicles were submitted to in vitro maturation for 44 h in TCM199 supplemented with 10 ng/ml EGF, 400 ng/ml pFSH and 570 microM cysteamine; in vitro fertilized for 18 h in mTBM with 10(5) frozen-thawed percoll-selected sperms/ml; and developed for 7 days in mSOF. Samples of oocytes or presumptive zygotes were fixed and stained at the end of maturation and fertilization. Groups of oocytes were cultured for 3 h in the presence of 35S-methionine before or after maturation for SDS-PAGE analysis of protein neosynthesis. More oocytes originating from medium and large follicles were competent for maturation than oocytes from small follicles (77 and 86% of metaphase II, respectively, versus 44%, P < 0.05). More oocytes from medium and large follicles werepenetratedby spermatozoa during in vitro fertilization, resulting in significantly more oocytes presenting two or more pronuclei at the end of fertilization (73 and 77% for medium and large follicles, respectively, versus 53% for small follicles, P < 0.05). More oocytes from medium and large follicles developed to the blastocyst stage (14 and 23%, respectively) than those from small follicles (3%, P < 0.05), even if the development rates were corrected by the maturation or fertilization rates. It is concluded that a high proportion of oocytes harvested from follicles of less than 3 mm in the pig are not fully competent for meiosis and are cytoplasmically deficient for development.

Animals↗

PubMed2002

Cyclooxygenase-2 is expressed by cumulus cells during oocyte maturation in cattle.

Prostaglandins could be involved in various aspects of final differentiation of ovarian follicles. Prostaglandins are generated by the cyclooxygenase (cox) pathway. Until now, the expression pattern of isoforms cox-1 and cox-2 of cyclooxygenase in bovine cumulus-oocyte complexes (COCs) was unknown. Using immunodetection procedure, we demonstrated in the present study that cox-2 was expressed by cumulus cells during in vivo and in vitro maturation. Time course induction of cox-2 expression was investigated during in vitro maturation using Western blot analysis. Specific signal of cox-2 was markedly evidenced from 6 hr of culture and increased to reach a maximal level at 24 hr of culture. In vitro, cox-2 expression in COCs was associated with increased concentrations of PGE(2) and PGF(2alpha) in the maturation medium. In addition, the effects of culture conditions on cox-2 expression was considered using RT-PCR and Western-blot analysis. We demonstrated that the addition of 10 ng/ml of EGF to TCM199 clearly increased the expression level of cox-2 mRNA and protein. Higher levels of in vitro cox-2 expression was associated with greater rates of cumulus expansion and oocytes at metaphase II at 24 hr of culture. In conclusion, our present results suggest that cox-2 expression in cumulus cells may be involved in differentiation of COCs that occurs during oocyte maturation.

Animals↗

PubMed2002

Interactions of platelets with Synthocytes, a novel platelet substitute.

A platelet substitute, Synthocytes, is being developed for the prevention and treatment of thrombocytopenia. Synthocytes are composed of fibrinogen adsorbed on heat stabilised albumin microcapsules of defined size. The purpose of this study was to perform experiments in vitro to investigate the capacity of Synthocytes to interact with platelets, one of the means through which Synthocytes may contribute to haemostatic plug formation in vivo. Synthocytes were found to interact with platelets as shown by platelet aggregation assays and measurements of [(14)C]5HT release from platelets in whole blood and platelet-rich plasma. Platelet-Synthocytes co-aggregate formation was demonstrated directly using flow cytometry and the presence of activated platelets in these co-aggregates was demonstrated using an antibody to P-selectin. Synthocytes enhanced platelet responsiveness to conventional aggregating agents such as ADP. Indeed, antagonists of the action of ADP on platelets inhibited the direct effects of Synthocytes on platelets in whole blood, as did a GPIIb/IIIa antagonist. Enhancement of annexin V binding was also observed, indicative of increased pro-coagulant activity. Experiments performed with control microcapsules (lacking fibrinogen) confirmed the importance of fibrinogen in the interactions that occurred. The results suggest that fibrinogen on the surface of Synthocytes can interact with GPIIb/IIIa on platelets to induce platelet activation, secretory activity and aggregation, and that ADP contributes to this process. This initial interaction renders platelets more susceptible to the stimulatory effects of other platelet-activating agents. It is considered likely that in the clinical setting of thrombocytopenia any interaction between Synthocytes and residual platelets that are present may contribute to primary haemostasis.

Adenosine Diphosphate↗

PubMed2002

Low molecular weight heparin-loaded polymeric nanoparticles: formulation, characterization, and release characteristics.

The aim of the present work was to investigate the preparation of low molecular weight heparin (LMWH) nanoparticles (NP) as potential oral heparin carriers. The NP were formulated using an ultrasound probe by water-in-oil-in-water (w/o/w) emulsification and solvent evaporation with two biodegradable polymers [poly-epsilon-caprolactone, PCL and poly(D,L-lactic-co-glycolic acid) 50/50, PLGA] and two non-biodegradable positively charged polymers (Eudragit RS and RL) used alone or in combination. The mean diameter of LMWH-loaded NP ranged from 240 to 490 nm and was dependent on the reduced viscosity of the polymeric organic solution. The surface potential of LMWH NP prepared with Eudragit polymers used alone or blended with PCL and PLGA was changed dramatically from strong positive values obtained with unloaded NP to negative values. The highest encapsulation efficiencies were observed when Eudragit polymers took part in the composition of the polymeric matrix, compared with PCL and PLGA NP exhibiting low LMWH entrapment. The in vitro LMWH release in phosphate buffer from all formulations ranged from 10 to 25% and was more important (two- to threefold) when esterase was added into the dissolution medium. The in vitro biological activity of released LMWH, determined by the anti-factor Xa activity with a chromogenic substrate, was preserved after the encapsulation process, making these NP good candidates for oral administration.

Acrylic Resins↗

PubMed2002

Preparation and characterization of heparin-loaded polymeric microparticles.

Microparticles containing heparin were prepared by a water-in-oil-in-water emulsification and evaporation process with pure or blends of biodegradable (poly-epsilon-caprolactone and poly(D,L-lactic-co-glycolic acid)) and of positively-charged non-biodegradable (Eudragit RS and RL) polymers. The influence of polymers and some excipients (gelatin A and B, NaCl) on the particle size, the morphology, the heparin encapsulation rate as well as the in vitro drug release was investigated. The diameter of the microparticles prepared with the various polymers ranged from 80 to 130 microns and was found to increase significantly with the addition of gelatin A into the internal aqueous phase. Microparticles prepared with Eudragit RS and RL exhibited higher drug entrapment efficiency (49 and 80% respectively) but lower drug release within 24 h (17 and 3.5% respectively) than those prepared with PCL and PLAGA. The use of blends of two polymers in the organic phase was found to modify the drug entrapment as well as the heparin release kinetics compared with microparticles prepared with a single polymer. In addition, microparticles prepared with gelatin A showed higher entrapment efficiency, but a significant initial burst effect was observed during the heparin release. The in vitro biological activity of heparin released from the formulations affording a suitable drug release has been tested by measuring the anti-Xa activity by a colorimetric assay with a chromogenic substrate. The results confirmed that heparin remained unaltered after the entrapment process.

Acrylic Resins↗

PubMed2001

Protein C-loaded monomethoxypoly (ethylene oxide)-poly(lactic acid) nanoparticles.

This paper deals with the preparation and characterization of monomethoxypoly(ethylene oxide)-poly(lactic acid) (MPEO-PLA) nanoparticles containing protein C, a plasma inhibitor which regulates the mechanism of blood coagulation. Protein C was entrapped in MPEO-PLA nanoparticles using the double emulsion method. The influence of MPEO-PLA copolymers on the different parameters was evaluated: characteristics of protein C-loaded nanoparticles, in vitro release of the protein, evolution of the particle size with incubation time and MPEO release. The nanoparticle size does not depend on copolymer characteristics (MPEO and/or PLA block molecular weight). On the other hand, the efficiency of protein C entrapment is affected by the copolymer characteristics. The burst effect during the protein C release is increased with the hydrophilic character of the copolymer. Moreover, protein C adsorption on the particle surface during its release may be related to MPEO release. Only 25% of the released protein C is active, which clearly illustrates that it is altered during its encapsulation. The optimization of the experimental parameters which disturbed entrapped protein C activity, i.e. sonication time and organic solvent was investigated and has led to a preservation of protein C activity. Then, to optimize its entrapment efficiency, a blend PLA/MPEO-PLA (25/75) was used to prepare nanoparticles. This blend limited burst effect of protein C and its adsorption. However, protein C is only partially released which implicates further investigation for a potential therapeutic use.

Lactates↗

PubMed2001

[Diagnosis and treatment of bladder tumors by photodynamic therapy].

Experimental results and clinical trials showed that bladder tumours Tis and pT1a can be diagnosed by photodynamic diagnosis and treated by photodynamic therapy. These photochemical methods are based on a selective photosensitizer uptake in the tumour tissue. After subsequent irradiation, these tissues emit a fluorescence (diagnosis) or can be destroyed by chemically induced oxidative compounds (treatment). Hematoporphyrin derivative and its oligomeric part have been the light-sensitizing drugs the most commonly studied. Interest has now shifted to 5-aminolevulinic acid, or its hexylester form, inducing protoporphyrin IX which shows better tumour localising properties and could avoid side effects. While photodynamic treatment is still an experimental modality, photodynamic diagnosis could achieve a more accurate detection of occult dysplasia compared to white light cystoscopy.

Aminolevulinic Acid↗

PubMed2001

Measurement of blood volume after haemodilution with haemoglobin-based oxygen carriers by a radiolabelled-albumin method.

Recent studies have shown that the use of haemoglobin-based oxygen-carrying solutions (HBOCs) for perioperative haemodilution could significantly reduce the need for packed red blood cells in clinical practice. Though the effects of HBOCs on plasma volume have been characterized in experimental models of volume resuscitation from hypovolaemic shock, little is known about their action in normovolaemic haemodilution conditions. We therefore applied a radiolabelled serumalbumin method to determine blood volume after haemodilution with crosslinked or conjugated haemoglobin, in comparison with a reference solution of hydroxyethyl starch (HES). Three groups of New Zealand white rabbits were studied (n = 7 each group) subjected to moderate exchange transfusion with low molecular weight HES, bis(3,5-dibromosalicyl)fumarate crosslinked haemoglobin (alphaalpha-Hb), or dextran-conjugated haemoglobin (Hb-Dex-BTC). HES induced no changes in heart rate and blood pressure. The amplitude and duration of blood pressure increase and bradycardia were similar in both haemoglobin groups. A significant contraction of blood volume (12%) was observed 60 min after haemodilution with alphaalpha-Hb, compared to HES and Hb-Dex-BTC. At the same time point, a decrease in absolute haemoglobin (plasma haemoglobin x plasma volume) was also noted. This study suggests that in haemodilution conditions, the specific oncotic properties and circulating persistence of crosslinked and conjugated haemoglobin solutions affect the pattern of blood volume distribution differently.

Animals↗

PubMed2001

Effects of three Hb-based oxygen-carrying solutions on neutrophil activation in vitro: quantitative measurement of the expression of adherence receptors.

BACKGROUND: Hb-based oxygen carriers (HbOCs) are currently under investigation as RBC substitutes. These solutions have vasoactive properties and may modify the behavior of the RBC in vitro. The effects of these agents on other blood cells have not been extensively investigated. The aim of this study was to evaluate the potential effect(s) of three differently modified HbOCs on the activation of PMNs. STUDY DESIGN AND METHODS: Whole blood from humans was incubated with Hb dextran-benzene-tetracarboxylate, alphaalpha-Hb, or o-raffinose-poly-Hb for 15, 30, and 60 minutes. The expression of adherence receptors CD62L, CD18, and CD11b, which reflects the activation state of the neutrophils, was assessed in vitro by a direct immunofluorescence method using calibration beads measured by flow cytometry. RESULTS: The observed expression of each of the three adherence receptors for each solution at each time point was similar to that noted with the RPMI control. Decreases in CD62L and increases in CD18 expression were noted at 15 minutes of incubation but, when those values were compared to the values obtained with TNFalpha as the positive control of PMN activation, the profile of expression of adherence receptors obtained with HbOC solutions did not conform to the expected activation profile of PMNs. CONCLUSION: Hb solutions modified by a variety of methods, as obtained and employed in this study, did not appear to activate neutrophils in vitro.

Aspirin↗

PubMed2000

Involvement of neutrophilic granulocytes in the uptake of biodegradable non-stealth and stealth nanoparticles in guinea pig.

The in vivo behavior of monomethoxypoly(ethylene oxide)-poly(lactic acid) (MPEO20-PLA45/PLA (75/25)) nanoparticles in comparison with PLA ones was studied in guinea pig. Indeed, the aim of this study was to bring to the fore the in vivo stealth character of these copolymer nanoparticles and to identify the phagocytic circulating cells involved in their uptake. After the intravascular administration of fluorescent nanoparticles (rubrene), their phagocytosis by granulocytes and monocytes was assayed by flow cytometry. At the same time, the evolution of the number of these phagocytic cells was realized in order to identify their function in the nanoparticle uptake. Finally, a histological study of the spleen (30 h after the nanoparticle administration) was investigated to highlight the splenic trapping of these stealth nanoparticles. This study has shown that the phagocytic circulating cells involved in the nanoparticle uptake were mainly neutrophilic granulocytes and some of them were found in the spleen.

Animals↗

PubMed2000

Biosynthesis and photodynamic efficacy of protoporphyrin IX (PpIX) generated by 5-aminolevulinic acid (ALA) or its hexylester (hALA) in rat bladder carcinoma cells.

Hexylester of 5-aminolevulinic acid (hALA) has been considered as an alternative to 5-aminolevulinic acid (ALA) for the treatment of malignancies of different origin. The present study addresses the ALA and hALA-induced PpIX pharmacokinetic profile using rat bladder carcinoma cells (AY27). The total PpIX content measured spectrofluorimetrically after extraction procedure at the end of 2 h incubation was at least 1.5-fold greater with hALA compared to ALA despite the difference in concentration of several orders between the two compounds (1 or 5 mM ALA and 5 or 10 x 10(-3) mM hALA). Considerable PpIX efflux was detected in the extracellular medium at the end of the incubation. With 5 mM ALA and 10 x 10(-3) mM hALA, PpIX build-up was continued beyond the incubation period pointing out to enzyme saturation in the biosynthetic pathway or/and the constitution of ALA reserve. Red laser light (lambda=630 nm) irradiation of AY27 cells after 2 h incubation with increasing ALA or hALA concentrations resulted in a nearly equal photocytotoxicity.

Aminolevulinic Acid↗

PubMed2000

Determination of the maximal carcinoma/normal skin ratio after HpD or m-THPC administration in Hairless mice (SKH-1) by fluorescence spectroscopy.

The two major steps in our study on the treatment of skin carcinomas by photochemotherapy (PCT) were the development of a skin tumor model in Hairless mice by a chemical carcinogenesis and the use of fluorescence spectroscopy, a semi-quantitative and non-invasive method, in order to determine the time after i.p. injection of photosensitizer when the tumor/normal skin ratio was the highest. A three-step carcinogenesis protocol provided mice bearing carcinomas and these were used to determine the tumor/normal skin ratios of two photosensitizers by fluorescence spectroscopy. Hematoporphyrin derivative (HpD) (5 mg/kg body weight) and m-tetra(hydroxyphenyl) chlorine (m-THPC) (0.3 mg/kg body weight) were injected i.p., and fluorescence was measured at 1, 4, 8, 12, 24, 48, 72 and 96 h after injection. The best carcinoma/normal skin ratio would be 3.2+/-1.4 for HpD and 2.7+/-2.1 for m-THPC, respectively. The delays required to reach these ratios were 72 h for HpD and 24 h for m-THPC. These results have to be considered with caution due to the high SEs and they must be confirmed by organic extraction. Photodynamic therapy with the same doses of HpD and m-THPC used in this pharmacokinetic study has to be carried out in order to compare the toxicities of the two photosensitizers and to determine which one is the best for this type of tumor.

Animals↗

PubMed2000

Systemic and renal hemodynamics after moderate hemodilution with HbOCs in anesthetized rabbits.

Hb-based O(2)-carrying solutions (HbOCs) have been developed as red blood cell substitutes for use in patients undergoing hemodilution. Variously modified Hb with diverse solution properties have been shown to produce variable hemodynamic responses. We examined, through pulsed-Doppler velocimetry, the systemic and renal hemodynamic effects of dextran-benzene-tetracarboxylate-conjugated (Hb-Dex-BTC), bis(3,5-dibromosalicyl)fumarate cross-linked (alphaalpha-Hb), and o-raffinose-polymerized (o-raffinose-Hb) Hb perfused in rabbits after moderate hemodilution (30% hematocrit), and we compared the effects of these Hb solutions with the effects elicited by plasma volume expanders. In addition, vascular hindrance (resistance/blood viscosity at 128.5 s(-1)) was calculated to determine whether a moderate decrease in the viscosity of blood mixed with HbOCs may impair vasoconstriction as a result of autoregulation after infusion of cell-free Hb. No changes were observed in renal hemodynamics after hemodilution with reference or Hb solutions. Increase in blood pressure and vascular resistance was found with Hb-Dex-BTC and alphaalpha-Hb (for 180 min) and, to a lesser extent, with o-raffinose-Hb (for 120 min). Furthermore, Hb-Dex-BTC (high viscosity) and o-raffinose-Hb (medium viscosity) induced comparable increases in vascular hindrance (from 0.091 to 0. 159 and from 0.092 to 0.162 cm(-1), respectively) but far less than that produced by alphaalpha-Hb (low viscosity, from 0.092 to 0.200 cm(-1)). These results suggest that maintaining the viscosity of blood by infusing solutions with high viscosity makes it possible to limit vasoconstriction due to autoregulation mechanisms and mainly caused by hemodilution per se.

Animals↗

PubMed1999

Preparation and characterization of protein C-loaded PLA nanoparticles.

This paper deals with the preparation and the characterization of poly(lactic acid) (PLA) nanoparticles containing protein C, a plasma inhibitor. Nanoparticles were prepared by the double emulsion method (w/o/w), using methylene chloride as an organic solvent and polyvinyl alcohol (PVA) or human serum albumin (HSA) as a surfactant. The influence of experimental constraints such as sonication and organic solvent on protein C activity was evaluated. It appears that a short time of sonication as well as the addition of acetone to methylene chloride (1/1) limited the lost of protein C activity. The study of protein C adsorption on blank PLA nanoparticles gave evidence to hydrophobic interactions between these two entities. The increase in PLA molecular weight on the characteristics of the protein C-loaded nanoparticles led to both a slightly decreased particle size and a lower polydispersity index, whereas the entrapment efficiency of protein C was not affected. The use of HSA as a surfactant allowed the increase in the entrapment efficiency of protein C but prevented its release. Finally, the evaluation of the activity of released protein C clearly illustrates that it was disturbed during the nanoparticle preparation. Thus, the obtained results emphasize the potential of protein C-loaded biodegradable nanoparticles for protein progressive delivery in plasma.

Anticoagulants↗

PubMed1999

MPEO-PLA nanoparticles: effect of MPEO content on some of their surface properties.

Nanoparticles of poly(lactic acid) (PLA) and of blends of PLA and monomethoxypoly(ethylene oxyde) (MPEO-PLA) were prepared by the double emulsion method. Sucrose was added to overcome nanoparticle aggregation with freeze-drying. Whereas PLA nanoparticles rapidly are phagocytosed by the mononuclear phagocyte system cells, the uptake of MPEO-PLA nanoparticles is delayed. Opsonization is one of the steps of phagocytosis, and serum complement is a major component of the opsonin system. The in vitro complement consumption of the prepared nanoparticles was evaluated as a function of time and of their surface area. To avoid the aggregation of MPEO-PLA nanoparticles due to MPEO crystallization, sucrose was necessary, and its concentration was dependent on MPEO proportion in the nanoparticle suspension. As expected, the complement consumption for PLA nanoparticles is faster and more important than for PLA/MPEO-PLA blends. The complement consumption decreases with the increase in MPEO surface density. Complement is less consumed with the lower surface density provided by a higher molecular weight than by the higher surface density provided by a lower molecular weight MPEO. The complement consumption seems to be dependent on the number of nanoparticles in contact with human serum. Finally, the model of steric repulsion of MPEO towards proteins and the importance of the surface density of MPEO were emphasized.

Biocompatible Materials↗