Artificial Oxygen Carriers, Hemoglobin Vesicles and Albumin−Hemes, Based on Bioconjugate Chemistry

Hemoglobin-Based Nanoarchitectonic Assemblies as Oxygen Carriers

Safe and effective artificial oxygen carriers are the subject of great interest due to the problems of traditional blood transfusion and enormous demand in clinical use. In view of its unique oxygen-transport ability and normal metabolic pathways, hemoglobin is regarded as an ideal oxygen-carrying unit. With advances in nano-biotechnology, hemoglobin assemblies as artificial oxygen carriers achieve great development. Here, recent progress on hemoglobin-based oxygen carriers is highlighted in view of two aspects: acellular hemoglobin-based oxygen carriers and cellular hemoglobin-based oxygen carriers. These novel oxygen carriers exhibit advantages over traditional carriers and will greatly promote research on reliable and feasible oxygen carriers.

Pro-apoptotic and pro-differentiation induction by 8-quinolinecarboxaldehyde selenosemicarbazone and its Co(iii) complex in human cancer cell lines

The ligand initiated reprogramming of cancer stem cells phenotype in AsPC-1 cells. The complex digested plasmid DNA which might be the cause of its cytotoxic activity.

Tissue Discs: A 3D Model for Assessing Modulation of Tissue Oxygenation

The presence of hypoxia in solid tumours is correlated with poor treatment outcome. We have developed a 3-D tissue engineered construct to quantitatively monitor oxygen penetration through tumour tissue using the exogenous 2-nitroimidazole bioreductive probe pimonidazole and phosphorescence quenching technologies. Using this in vitro model we were able to examine the influence of the biguanides metformin and phenformin, antimycin A and KCN, on the distribution and kinetics of oxygen delivery as prototypes of modulators of oxygen metabolism.

Pharmacokinetic Properties of Single and Repeated Injection of Liposomal Platelet Substitute in a Rat Model of Red Blood Cell Transfusion-Induced Dilutional Thrombocytopenia

A preclinical study of dodecapeptide ((400)HHLGGAKQAGDV(411)) (H12)-(adenosine diphosphate, ADP)-liposomes for use as a synthetic platelet (PLT) substitute under conditions of red blood cell (RBC) transfusion-induced dilutional thrombocytopenia is limited to pharmacological effect. In this study, the pharmacokinetics of H12-(ADP)-liposomes in RBC transfusion-induced dilutional thrombocytopenic rats were evaluated. As evidenced by the use of (14) C, (3) H double-radiolabeled H12-(ADP)-liposomes in which the encapsulated ADP and liposomal membrane were labeled with (14) C and (3) H, respectively, the H12-(ADP)-liposomes remained intact in the blood circulation for up to 3 h after injection, and were mainly distributed to the liver and spleen. The encapsulated ADP was mainly eliminated in the urine, whereas the outer membrane was mainly eliminated in the feces. These successive pharmacokinetic properties of the H12-(ADP)-liposomes in RBC transfusion-induced dilutional thrombocytopenic rats were similar to those in healthy rats, except for the shorter retention time in the circulation. When H12-(ADP)-liposomes were repeatedly injected into RBC transfusion-induced dilutional thrombocytopenic rats at intervals of 5 days at a dose of 10 mg lipids/kg, the second dose of injected H12-(ADP)-liposomes were rapidly cleared from the circulation, namely, via the accelerated blood clearance phenomenon. These novel pharmacokinetic findings provide useful information for the further development of H12-(ADP)-liposomes as a PLT substitute.

Potential electron mediators to extract electron energies of RBC glycolysis for prolonged in vivo functional lifetime of hemoglobin vesicles

Developing a functional blood substitute as an alternative to donated blood for clinical use is believed to relieve present and future blood shortages, and to reduce the risks of infection and blood type mismatching. Hemoglobin vesicle (HbV) encapsulates a purified and concentrated human-derived Hb solution in a phospholipid vesicle (liposome). The in vivo safety and efficacy of HbV as a transfusion alternative have been clarified. Auto-oxidation of ferrous Hb in HbV gradually increases the level of ferric methemoglobin (metHb) and impairs the oxygen transport capabilities. The extension of the functional half-life of HbV has recently been proposed using an electron mediator, methylene blue (MB), which acts as a shuttle between red blood cells (RBC) and HbV. MB transfers electron energies of NAD(P)H, produced by RBC glycolysis, to metHb in HbV. Work presented here focuses on screening of 15 potential electron mediators, with appropriate redox potential and water solubility, for electron transfer from RBC to HbV. The results are assessed with regard to the chemical properties of the candidates. The compounds examined in this study were dimethyl methylene blue (DMB), methylene green, azure A, azure B, azure C, toluidine blue (TDB), thionin acetate, phenazine methosulfate, brilliant cresyl blue, cresyl violet, gallocyanine, toluylene blue, indigo carmine, indigotetrasulfonate, and MB. Six candidates were found to be unsuitable because of their insufficient diffusion across membranes, or overly high or nonexistent reactivity with relevant biomolecules. However, 9 displayed favorable metHb reduction. Among the suitable candidates, phenothiazines DMB and TDB exhibited effectiveness like MB did. In comparison to MB, they showed faster reduction by electron-donating NAD(P)H, coupled with showing a lower rate of reoxidation in the presence of molecular oxygen. Ascertaining the best electron mediator can provide a pathway for extending the lifetime and efficiency of potential blood substitutes.

Synthesis and photophysical properties of β-triazole bridged porphyrin–coumarin dyads

Novel β-triazole bridged porphyrin–coumarin dyads are synthesized via a Cu(i)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction and evaluated for their photophysical properties.

Composite copolymer hybrid silver nanoparticles: preparation and characterization of antibacterial activity and cytotoxicity

The AgNPs could adhere to the bacterial membrane through electrostatic force, then damage the bacterial membrane irreversibly and lead to bacterial apoptosis finally.

Protoporphyrin incorporated alginate hydrogel: preparation, characterization and fluorescence imaging in vivo

A protoporphyrin incorporated alginate hydrogel exhibits the fluorescence ability to locate a drug and carrier with multispectral fluorescence imaging in vivo.

Red blood cells donate electrons to methylene blue mediated chemical reduction of methemoglobin compartmentalized in liposomes in blood

Electron-energy-rich coenzymes in cells, NADH and NADPH, are re-energized repeatedly through the Embden-Meyerhof and pentose-phosphate glycolytic pathways, respectively. This study demonstrates extraction of their electron energies in red blood cells (RBCs) for in vivo extracellular chemical reactions using an electron mediator shuttling across the biomembrane. Hemoglobin-vesicles (HbVs) are an artificial oxygen carrier encapsulating purified and concentrated Hb solution in liposomes. Because of the absence of a metHb-reducing enzymatic system in HbV, HbO2 gradually autoxidizes to form metHb. Wistar rats received HbV suspension (10 mL/kg body weight) intravenously. At the metHb level of around 50%, methylene blue [MB(+); 3,7-bis(dimethylamino)phenothiazinium chloride] was injected. The level of metHb quickly decreased to around 16% in 40 min, remaining for more than 5 h. In vitro mixing of HbV/MB(+) with RBCs recreated the in vivo metHb reduction, but not with plasma. NAD(P)H levels in RBCs decreased after metHb reduction. The addition of glucose facilitated metHb reduction. Liposome-encapsulated NAD(P)H, a model of RBC, reduced metHb in HbV in the presence of MB(+). These results indicate that (i) NAD(P)H in RBCs reacts with MB(+) to convert it to leukomethylene blue (MBH); (ii) MB(+) and MBH shuttle freely between RBC and HbV across the hydrophobic lipid membranes; and (iii) MBH is transferred into HbV and reduces metHb in HbV. Four other electron mediators with appropriate redox potentials appeared to be as effective as MB(+) was, indicating the possibility for further optimization of electron mediators. We established an indirect enzymatic metHb reducing system for HbV using unlimited endogenous electrons created in RBCs in combination with an effective electron mediator that prolongs the functional lifespan of HbV in blood circulation.

Expression and purification of recombinant human serum albumin from selectively terminable transgenic rice

Human serum albumin (HSA) is widely utilized for medical purposes and biochemical research. Transgenic rice has proved to be an attractive bioreactor for mass production of recombinant HSA (rHSA). However, transgene spread is a major environmental and food safety concern for transgenic rice expressing proteins of medical value. This study aimed to develop a selectively terminable transgenic rice line expressing HSA in rice seeds, and a simple process for recovery and purification of rHSA for economical manufacture. An HSA expression cassette was inserted into a T-DNA vector encoding an RNA interference (RNAi) cassette suppressing the CYP81A6 gene. This gene detoxifies the herbicide bentazon and is linked to the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) cassette which confers glyphosate tolerance. ANX Sepharose Fast Flow (ANX FF) anion exchange chromatography coupled with Butyl Sepharose High Performance (Butyl HP) hydrophobic interaction chromatography was used to purify rHSA. A transgenic rice line, HSA-84, was obtained with stable expression of rHSA of up to 0.72% of the total dry weight of the dehusked rice seeds. This line also demonstrated high sensitivity to bentazon, and thus could be killed selectively by a spray of bentazon. A two-step chromatography purification scheme was established to purify the rHSA from rice seeds to a purity of 99% with a recovery of 62.4%. Results from mass spectrometry and N-terminus sequencing suggested that the purified rHSA was identical to natural plasma-derived HSA. This study provides an alternative strategy for large-scale production of HSA with a built-in transgene safety control mechanism.

Dextran-based thermo-responsive hemoglobin–polymer conjugates with oxygen-carrying capacity

Graft copolymer dextran-g-poly(NIPAAm) was synthesized via SET-LRP and covalently attached to bovine hemoglobin to form thermo-responsive protein–polymer conjugates as novel oxygen carriers.

Warfarin modulates the nitrite reductase activity of ferrous human serum heme-albumin

Human serum heme-albumin (HSA-heme-Fe) displays reactivity and spectroscopic properties similar to those of heme proteins. Here, the nitrite reductase activity of ferrous HSA-heme-Fe [HSA-heme-Fe(II)] is reported. The value of the second-order rate constant for the reduction of [Formula: see text] to NO and the concomitant formation of nitrosylated HSA-heme-Fe(II) (i.e., k on) is 1.3 M(-1) s(-1) at pH 7.4 and 20 °C. Values of k on increase by about one order of magnitude for each pH unit decrease between pH 6.5 to 8.2, indicating that the reaction requires one proton. Warfarin inhibits the HSA-heme-Fe(II) reductase activity, highlighting the allosteric linkage between the heme binding site [also named the fatty acid (FA) binding site 1; FA1] and the drug-binding cleft FA2. The dissociation equilibrium constant for warfarin binding to HSA-heme-Fe(II) is (3.1 ± 0.4) × 10(-4) M at pH 7.4 and 20 °C. These results: (1) represent the first evidence for the [Formula: see text] reductase activity of HSA-heme-Fe(II), (2) highlight the role of drugs (e.g., warfarin) in modulating HSA(-heme-Fe) functions, and (3) strongly support the view that HSA acts not only as a heme carrier but also displays transient heme-based reactivity.

Novel Nanodimension artificial red blood cells that act as O2 and CO2 carrier with enhanced antioxidant activity: PLA-PEG nanoencapsulated PolySFHb-superoxide dismutase-catalase-carbonic anhydrase

Poly(ethylene glycol)-Poly(lactic acid) block-copolymer (PEG-PLA) was prepared and characterized using Fourier transform infrared spectrophotometer (FTIR). Glutaraldehyde was used to crosslink stroma-free hemoglobin (SFHb), superoxide dismutase (SOD), catalase (CAT), and carbonic anhydrase (CA) into a soluble complex of PolySFHb-SOD-CAT-CA. PEG-PLA was then used to nanoencapsulated PolySFHb-SOD-CAT-CA by oil in water emulsification. This resulted in the formation of PLA-PEG-PolySFHb-SOD-CAT-CA nanocapsules that have enhanced antioxidant activity and that can transport both O2 and CO2. These are homogeneous particles with an average diameter of 100 nm with good dispersion and core shell structure, high entrapment efficiency (EE%), and nanocapsule percent recovery. A lethal hemorrhagic shock model in rats was used to evaluate the therapeutic effect of the PLA-PEG-PolySFHb-SOD-CAT-CA nanocapsules. Infusion of this preparation resulted in the lowering of the elevated tissue PCO2 and also recovery of the mean arterial pressure (MAP).

Interaction of FeIII-tetra-(4-sulfonatophenyl)-porphyrin with copolymers and aggregation in complex micelles

Aggregation of Fe(III)-tetra-(4-sulfonatophenyl)-porphyrin (Fe(III)TPPS) was studied in the presence of block copolymers, poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG-b-P4VP), poly(ethylene glycol)-block-poly(2-(dimethylamino)ethyl methylacrylate) (PEG-b-PDMAEMA), and poly(ethylene glycol)-block-poly(β-cyclodextrin) (PEG-b-PCD). The interaction between the iron porphyrin and the blocks, P4VP, PDMAEMA, and PCD, led to the formation of copolymers/Fe(III)TPPS complex micelles with a PEG shell and determined the species of Fe(III)TPPS. The electrostatic interaction of protonated P4VP and PDMAEMA with Fe(III)TPPS remarkably decreased the apparent pKd of Fe(III)TPPS and led to a micellar μ-oxo dimer of the iron porphyrin. At pH above the pKa of P4VP, Fe(III)TPPS was kept inside the hydrophobic P4VP core and formed an encapsulated μ-oxo dimer. However, when above the pKa of PDMAEMA, Fe(III)TPPS escaped from the hydrophobic PDMAEMA core, existing as a free μ-oxo dimer. PCD caused the monomer of the porphyrin because of the inclusion complexation between the β-cyclodextrin residues and Fe(III)TPPS. The two micellar monomer species Fe(III)TPPS(H2O)2 and Fe(III)TPPS(OH) were obtained with an equilibrium pKa ~ 6.4.

Blood substitutes: evolution from noncarrying to oxygen- and gas-carrying fluids

The development of oxygen (O2)-carrying blood substitutes has evolved from the goal of replicating blood O2 transport properties to that of preserving microvascular and organ function, reducing the inherent or potential toxicity of the material used to carry O2, and treating pathologies initiated by anemia and hypoxia. Furthermore, the emphasis has shifted from blood replacement fluid to "O2 therapeutics" that restore tissue oxygenation to specific tissues regions. This review covers the different alternatives, potential and limitations of hemoglobin-based O2 carriers (HBOCs) and perfluorocarbon-based O2 carriers (PFCOCs), with emphasis on the physiologic conditions disturbed in the situation that they will be used. It describes how concepts learned from plasma expanders without O2-carrying capacity can be applied to maintain O2 delivery and summarizes the microvascular responses due to HBOCs and PFCOCs. This review also presents alternative applications of HBOCs and PFCOCs namely: 1) How HBOC O2 affinity can be engineered to target O2 delivery to hypoxic tissues; and 2) How the high gas solubility of PFCOCs provides new opportunities for carrying, dissolving, and delivering gases with biological activity. It is concluded that the development of current blood substitutes has amplified their applications horizon by devising therapeutic functions for O2 carriers requiring limited O2 delivery capacity restoration. Conversely, full, blood-like O2-carrying capacity reestablishment awaits the control of O2 carrier toxicity.

Examining and mitigating acellular hemoglobin vasoactivity

SIGNIFICANCE

There has been a striking advancement in our understanding of red cell substitutes over the past decade. Although regulatory oversight has influenced many aspects of product development in this period, those who have approached the demonstration of efficacy of red cell substitutes have failed to understand their implication at the level of the microcirculation, where blood interacts closely with tissue.

RECENT ADVANCES

The understanding of the adverse effects of acellular hemoglobin (Hb)-based oxygen carriers (HBOCs) has fortunately expanded from Hb-induced renal toxicity to a more complete list of biochemical mechanism. In addition, various unexpected adverse reactions were seen in early clinical studies. The effects of the presence of acellular Hb in plasma are relatively unique because of the convergence of mechanical and biochemical natures.

CRITICAL ISSUES

Controlling the variables using genetic engineering and chemical modification to change specific characteristics of the Hb molecule may allow for solving the complex multivariate problems of acellular Hb vasoactivity. HBOCs may never be rendered free of negative effects; however, quantifying the nature and extent of microvascular complications establishes a platform for designing new ameliorative therapies.

FUTURE DIRECTIONS

It is time to leave behind the study of vasoactivity and toxicity based on bench-top measurements of biochemical changes and those based solely on systemic parameters in vivo, and move to a more holistic analysis of the mechanisms creating the problems, complemented with meaningful studies of efficacy.

Hemoglobin-albumin cross-linking with disuccinimidyl suberate (DSS) and/or glutaraldehyde for blood substitutes

Hemoglobin (Hb) derivatization for blood substitute purposes often involves multi-step processes including redox reagents such as borohydride and periodate, with possible subsequent side effects. Disuccinimidyl suberate (DSS) allows protein cross-linking without toxic side-products, forming one-step peptide bonds with the lysine residues. Here, we report that Hb polymers were obtained using DSS, making this the first report of a single-step polymerization for blood substitutes. The increase in autooxidation rate incurred by this polymerization is completely reversed when BSA is copolymerized with Hb. Copolymerization of Hb with BSA appears to be beneficial for alleviating pro-oxidant effects, regardless of the polymerizing agent employed.

Modification of a dioxygen carrier, hemoCD, with PEGylated dendrons for extension of circulation time in the bloodstream

A supramolecular diatomic receptor, hemoCD, was modified with PEGylated dendrons to extend its circulation time in the bloodstream. The core component was 4-oxo-4-[[4-(10,15,20-tris(4-sulfonatophenyl)-21H,23H-porphin-5-yl)phenyl]amino]butanoic acid (Por-COOH). The building block of the dendrons was Fmoc-4-amino-4-(2-carboxyethyl)heptanedioic acid (FmocTA), which was condensed with α-amino-ω-methoxy-poly(ethylene glycol) (PEG(5000)-NH(2)) to yield an FmocG1-dendron. After deprotection, the G1-dendron was condensed with Por-COOH to yield G1-Por. A precursor (FmocNA) of an FmocG2-dendron was prepared via a condensation reaction of 4-amino-4-(2-t-butoxycarbonylethyl)heptanedioic acid di-t-butyl ester (TA-E) with FmocTA followed by hydrolysis of the resultant nona-carboxylic acid nona-t-butyl ester. Condensation of FmocNA with PEG(5000)-NH(2) yielded an FmocG2-dendron. After deprotection, the G2-dendron was condensed with Por-COOH to yield G2-Por. The ferrous complexes of G1- and G2-Pors formed stable 1:1 inclusion complexes with Py3CD, a per-O-methylated β-cyclodextrin dimer with a pyridine linker, in aqueous solution yielding supramolecular complexes designated as G1-hemoCD and G2-hemoCD, respectively. Both G1- and G2-hemoCDs bound molecular oxygen, with the O(2) affinities (P(1/2)) of hemoCD, G1-, and G2-hemoCDs at pH 7.4 and 37 °C being 22, 20, and 20 Torr, respectively. The modification of hemoCD with the dendrons did not cause destabilization of the O(2) adducts via autoxidation, as indicated by their half-lives (t(1/2)) of 6.8, 6.1, and 5.5 h for hemoCD, G1-, and G2-hemoCDs, respectively. The blood concentration-time curves of G1- and G2-hemoCDs injected into the bloodstream of rats exhibited two phases, with the half-lives of the fast and slow decays being 0.45 and 5.3 h, respectively, for G1-hemoCD, and 0.20 and 12.8 h, respectively, for G2-hemoCD. The half-lives of hemoCD were 0.02 and 0.50 h, respectively. The circulation time of hemoCD was markedly extended by its modification with the PEGylated dendrons, which was very effective in protecting hemoCD against opsonization for uptake by the reticuloendothelial system.

Chains, sheets, and droplets: assemblies of hydrophobic gold nanocrystals with saturated phosphatidylcholine lipid and squalene

Assemblies of saturated 1,2-diacylphosphatidylcholine lipid and hydrophobic dodecanethiol-capped 1.8 nm diameter gold nanocrystals were studied as a function of lipid chain length and the addition of the naturally occurring oil, squalene. The gold nanocrystals formed various lipid-stabilized agglomerates, sometimes fusing with lipid vesicle bilayers. The nanocrystal assembly structure depended on the hydrocarbon chain length of the lipid fatty acids. The lipid with the shortest fatty acid length studied, dilauroylphosphatidylcholine, created extended chains of gold nanocrystals. The lipid with slightly longer fatty acid chains created planar sheets of nanocrystals. Further increases of the fatty acid chain length led to spherical agglomerates. The inclusion of squalene led to lipid- and nanocrystal-coated oil droplets.

Low modulus biomimetic microgel particles with high loading of hemoglobin

We synthesized extremely deformable red blood cell-like microgel particles and loaded them with bovine hemoglobin (Hb) to potentiate oxygen transport. With similar shape and size as red blood cells (RBCs), the particles were fabricated using the PRINT (particle replication in nonwetting templates) technique. Low cross-linking of the hydrogel resulted in very low mesh density for these particles, allowing passive diffusion of hemoglobin throughout the particles. Hb was secured in the particles through covalent conjugation of the lysine groups of Hb to carboxyl groups in the particles via EDC/NHS coupling. Confocal microscopy of particles bound to fluorescent dye-labeled Hb confirmed the uniform distribution of Hb throughout the particle interior, as opposed to the surface conjugation only. High loading ratios, up to 5 times the amount of Hb to polymer by weight, were obtained without a significant effect on particle stability and shape, though particle diameter decreased slightly with Hb conjugation. Analysis of the protein by circular dichroism (CD) spectroscopy showed that the secondary structure of Hb was unperturbed by conjugation to the particles. Methemoglobin in the particles could be maintained at a low level and the loaded Hb could still bind oxygen, as studied by UV-vis spectroscopy. Hb-loaded particles with moderate loading ratios demonstrated excellent deformability in microfluidic devices, easily deforming to pass through restricted pores half as wide as the diameter of the particles. The suspension of concentrated particles with a Hb concentration of 5.2 g/dL showed comparable viscosity to that of mouse blood, and the particles remained intact even after being sheared at a constant high rate (1000 1/s) for 10 min. Armed with the ability to control size, shape, deformability, and loading of Hb into RBC mimics, we will discuss the implications for artificial blood.

Assessment of new cationic porphyrin binding to plasma proteins by planar microarray and spectroscopic methods

Porphyrins have a unique aromatic structure determining particular photochemical properties that make them promising photosensitizers for anticancer therapy. Previously, we synthesized a set of artificial porphyrins by modifying side-chain functional groups and introducing different metals into the core structure. Here, we have performed a comparative study of the binding properties of 29 cationic porphyrins with plasma proteins by using microarray and spectroscopic approaches. The porphyrins were noncovalently immobilized onto hydrogel-covered glass slides and probed to bio-conjugated human and bovine serum albumins, as well as to human hemoglobin. The signal detection was carried out at the near-infrared fluorescence wavelength (800 nm) that enabled the effect of intrinsic visible wavelength fluorescence emitted by the porphyrins tested to be discarded. Competition assays on porphyrin microarrays indicated that long-chain fatty acids (FAs) (palmitic and stearic acids) decrease porphyrin binding to both serum albumin and hemoglobin. The binding affinity of different types of cationic porphyrins for plasma proteins was quantitatively assessed in the absence and presence of FAs by fluorescent and absorption spectroscopy. Molecular docking analysis confirmed results that new porphyrins and long-chain FAs compete for the common binding site FA1 in human serum albumin and meso-substituted functional groups in porphyrins play major role in the modulation of conformational rearrangements of the protein.

Tuning the efficiency of dendritic nanocarriers using conformational constraints

A series of deoxycholic and cholic acid-derived oligomers were synthesized and their ability to extract hydrophilic dye molecules of different structure, size, and functional groups into nonpolar media was studied. The structure of the dye and "dendritic effect" in the extraction process was examined using absorption spectroscopy and dynamic light scattering (DLS). The efficiency of structurally preorganized oligomers in the aggregation process was evaluated by 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence studies. The possible formation of globular structures for higher-generation molecules was investigated by molecular modeling studies and the results were correlated with the anomaly observed in the extraction process with this molecule. The ability of these molecules for selective extraction of specific dyes from blended colors is also reported.

A novel water-soluble near-infrared glucose-conjugated porphyrin: synthesis, properties and its optical imaging effect

A simple novel near-infrared water-soluble glucose-conjugated porphyrin, 5,15-bis-[(trimethylsilyl)ethynyl]-10,20-bis[4-β-D-glucopyranosyl)phenyl]porphyrin, with good optical stability and high emission ability in near-infrared region, was synthesized. And Optical Imaging in vivo with this compound as probe was performed on liver tumor-bearing nude mice. The result shows that this glucose-conjugated porphyrin could display information in vivo more than 1 cm in depth, which implies its potential application as optical probe in cancer diagnosis.

Human serum albumin: from bench to bedside

Human serum albumin (HSA), the most abundant protein in plasma, is a monomeric multi-domain macromolecule, representing the main determinant of plasma oncotic pressure and the main modulator of fluid distribution between body compartments. HSA displays an extraordinary ligand binding capacity, providing a depot and carrier for many endogenous and exogenous compounds. Indeed, HSA represents the main carrier for fatty acids, affects pharmacokinetics of many drugs, provides the metabolic modification of some ligands, renders potential toxins harmless, accounts for most of the anti-oxidant capacity of human plasma, and displays (pseudo-)enzymatic properties. HSA is a valuable biomarker of many diseases, including cancer, rheumatoid arthritis, ischemia, post-menopausal obesity, severe acute graft-versus-host disease, and diseases that need monitoring of the glycemic control. Moreover, HSA is widely used clinically to treat several diseases, including hypovolemia, shock, burns, surgical blood loss, trauma, hemorrhage, cardiopulmonary bypass, acute respiratory distress syndrome, hemodialysis, acute liver failure, chronic liver disease, nutrition support, resuscitation, and hypoalbuminemia. Recently, biotechnological applications of HSA, including implantable biomaterials, surgical adhesives and sealants, biochromatography, ligand trapping, and fusion proteins, have been reported. Here, genetic, biochemical, biomedical, and biotechnological aspects of HSA are reviewed.

Large-scale production of functional human serum albumin from transgenic rice seeds

Human serum albumin (HSA) is widely used in clinical and cell culture applications. Conventional production of HSA from human blood is limited by the availability of blood donation and the high risk of viral transmission from donors. Here, we report the production of Oryza sativa recombinant HSA (OsrHSA) from transgenic rice seeds. The level of OsrHSA reached 10.58% of the total soluble protein of the rice grain. Large-scale production of OsrHSA generated protein with a purity >99% and a productivity rate of 2.75 g/kg brown rice. Physical and biochemical characterization of OsrHSA revealed it to be equivalent to plasma-derived HSA (pHSA). The efficiency of OsrHSA in promoting cell growth and treating liver cirrhosis in rats was similar to that of pHSA. Furthermore, OsrHSA displays similar in vitro and in vivo immunogenicity as pHSA. Our results suggest that a rice seed bioreactor produces cost-effective recombinant HSA that is safe and can help to satisfy an increasing worldwide demand for human serum albumin.

Towards hemerythrin-based blood substitutes: comparative performance to hemoglobin on human leukocytes and umbilical vein endothelial cells

Hemerythrin is a dioxygen-carrying protein whose oxidative/nitrosative stress-related reactivity is lower than that of hemoglobin, which may warrant investigation of hemerythrin as raw material for artificial oxygen carriers ('blood substitutes'). We report here the first biological tests for hemerythrin and its chemical derivatives, comparing their performance with that of a representative competitor, glutaraldehyde-polymerized bovine hemoglobin. Hemerythrin (native or derivatized) exhibits a proliferative effect on human umbilical vein endothelial cell (HUVEC) cultures, as opposed to a slight inhibitory effect of hemoglobin. A similar positive effect is displayed on human lymphocytes by glutaraldehyde-polymerized hemerythrin, but not by native or polyethylene glycol-derivatized hemerythrin.

Cationic amylose-encapsulated bovine hemoglobin as a nanosized oxygen carrier

Nanosized hemoglobin-based oxygen carriers are one of the most promising blood substitutes. In the present study, a comprehensive strategy for the preparation of nanosized cationic amylose-encapsulated hemoglobins (NCAHbs) was developed. First, cationic amylase (CA) was synthesized from amylose and quaternary ammonium salt by an etherification reaction. The structure of CA was characterized using Fourier transform infrared spectrophotometry (FTIR) and proton nuclear magnetic resonance spectrophotometry ((1)H NMR). The degree of substitution and the zeta potential were also measured. Then, the NCAHbs were prepared by electrostatic adhesion, reverse micelles and cross-linking. The UV-visible spectrophotometer was used to measure the entrapment efficiency (EE%) and drug loading efficiency (DL%) of the NCAHbs. Transmission electron microscopy and Malvern Nano-zs 90 analyzer were used to observe the size distribution and morphology of particles. Chemical structure was determined from the FTIR spectrum. A Hemox analyzer was used to measure the P(50) and Hill coefficients. A lethal hemorrhagic shock model in rats was used to evaluate the therapeutic effect of the NCAHbs. The results showed that the combined methods improved the size, stability, EE%, DL%, and oxygen-carrying capacity of the NCAHbs. The average diameter of the NCAHbs was 92.53 ± 3.64 nm, with a narrow polydispersity index of 0.027. The EE% was 80.05% ± 1.56% and DL% was 61.55% ± 1.41%. The P(50) and Hill coefficient were equal to 28.96 ± 1.33 mmHg and 2.55 ± 0.22, respectively. The size of NCAHbs remained below 200 nm for six days in PBS solution. The NCAHbs could effectively prevent lung injury from progressing to lethal hemorrhagic shock because they acted as both a volume expander and an oxygen carrier.