Selective Extraction and Quantification of Hemoglobin Based on a Novel Molecularly Imprinted Nanopolymeric Structure of Poly(acrylamide-vinyl imidazole)

Imbalances in hemoglobin (Hb) levels can lead to conditions such as anemia or polycythemia, emphasizing the importance of precise Hb extraction from blood. To address this, a novel synthetic imprinted polymer was meticulously developed for capturing and separating Hb. Poly(acrylamide-vinylimidazole) nanopolymer (poly(AAm-VIM)) was synthesized using acrylamide and vinyl imidazole as functional monomers through surfactant-free emulsion polymerization. Characterization using FTIR, particle size, zeta potential, and SEM ensured the polymer's structure. The Hb-imprinted nanopolymer (Hb-poly(AAm-VIM)) demonstrated notable specificity, with a calculated Hb-specific adsorption value (Qmax) of 3.7377 mg/g in a medium containing 2.5 mg/mL Hb. The molecularly imprinted polymer (MIP) exhibited approximately 5 times higher Hb adsorption than the nonimprinted polymer (NIP). Under the same conditions, the imprinted nanopolymer displayed 2.39 and 2.17 times greater selectivity for Hb over competing proteins such as bovine serum albumin (BSA) and lysozyme (Lys), respectively. Also, SDS-PAGE analysis results confirmed the purification of Hb by the molecularly imprinted nanopolymer. These results underscore the heightened specificity and efficacy of the molecularly imprinted nanopolymer in selectively targeting Hb atoms among other proteins. Incorporating such polymers is justified by their notable affinity, cost-effectiveness, and facile production. This research contributes valuable insights into optimizing synthetic imprinted polymers for efficient Hb extraction, with potential in medical diagnostics and treatment applications.

Carbon monoxide poisoning: A problem uniquely suited to a medicinal inorganic chemistry solution

Carbon monoxide poisoning is one of the most common forms of poisoning in the world. Although the primary mode of treatment, oxygen therapy, is highly effective in many cases, there are instances in which it is inadequate or inappropriate. Whereas oxygen therapy relies on high levels of a low-affinity ligand (O2) to displace a high-affinity ligand (CO) from metalloproteins, an antidote strategy relies on introducing a molecule with a higher affinity for CO than native proteins (Kantidote,CO > Kprotein,CO). Based on the fundamental chemistry of CO, such an antidote is most likely required to be an inorganic compound featuring an electron-rich transition metal. A review is provided of the protein-, supramolecular complex-, and small molecule-based CO poisoning antidote platforms that are currently under investigation.

Spontaneous reduction of iron(III)porphyrin to iron(II)porphyrin-CO complex in mouse circulation

Iron(II/III)porphyrin/cyclodextrin inclusion complexes serve as hemoprotein models in vivo. Here we showed the iron(III)porphyrin complex to be spontaneously reduced to its iron(II) state in mouse circulation. The reduced complex bound endogenous CO from carboxyhemoglobin, which was followed by urinary excretion. The natural reduction system was found to be effective for synthetic heme-model compounds.

Current perspectives of artificial oxygen carriers as red blood cell substitutes: a review of old to cutting-edge technologies using in vitro and in vivo assessments

Background

Several circumstances such as accidents, surgery, traumatic hemorrhagic shock, and other causalities cause major blood loss. Allogenic blood transfusion can be resuscitative for such conditions; however, it has numerous ambivalent effects, including supply shortage, needs for more time, cost for blood grouping, the possibility of spreading an infection, and short shelf-life. Hypoxia or ischemia causes heart failure, neurological problems, and organ damage in many patients. To address this emergent medical need for resuscitation and to treat hypoxic conditions as well as to enhance oxygen transportation, researchers aspire to achieve a robust technology aimed to develop safe and feasible red blood cell substitutes for effective oxygen transport.

Area covered

This review article provides an overview of the formulation, storage, shelf-life, clinical application, side effects, and current perspectives of artificial oxygen carriers (AOCs) as red blood cell substitutes. Moreover, the pre-clinical (in vitro and in vivo) assessments for the evaluation of the efficacy and safety of oxygen transport through AOCs are key considerations in this study. With the most significant technologies, hemoglobin- and perfluorocarbon-based oxygen carriers as well as other modern technologies, such as synthetically produced porphyrin-based AOCs and oxygen-carrying micro/nanobubbles, have also been elucidated.

Expert opinion

Both hemoglobin- and perfluorocarbon-based oxygen carriers are significant, despite having the latter acting as safeguards; they are cost-effective, facile formulations which penetrate small blood vessels and remove arterial blockages due to their nano-size. They also show better biocompatibility and longer half-life circulation than other similar technologies.

Binding of Dual-Function Hybridized MetalOrganic Capsules to Enzymes for Cascade Catalysis

The combination of chemo- and biocatalysis for multistep syntheses provides attractive advantages in terms of evolvability, promiscuity, and sustainability striving for desirable catalytic performance. Through the encapsulation of flavin analogues by both NADH and heme mimics codecorated heteroleptic metal-organic capsules, herein, we report a progressive host-guest strategy to imitate cytochrome P450s catalysis for cascade oxidative coupling catalysis. Besides the construction of stable dual-function metal-organic capsules and the modification of cofactor-decorated capsules at the domain of enzymes, this supramolecular strategy involves multistage directional electron flow, affording reactive ferric peroxide species for inducing oxygenation. Under light irradiation, the metal-organic capsule selectively converts stilbene to oxidative coupling products (including 2-oxo-1,2-diphenylethyl formate, 2-alkoxy-1,2-diphenylethanone) in tandem with enzymatic reactions respectively, at the domain of natural enzymes. The ingenious combination of capsules and enzymes with the in situ-regenerated capsule-loaded NADH cofactor promises non-native coupling reactions by forming regional cooperation and division. This abiotic-biotic conjugated host-guest strategy is conducive to the de novo creation of multifunctional components approaching active enzymatic sites for reinforced matter and energy transporting, demonstrating a key role of multicomponent supramolecular catalysts for one-pot integrated catalytic conversions.

Induced Near-Infrared Emission and Controlled Photooxidation based on Sulfonated Crown Ether in Water

Regulation of physio-chemical properties and reaction activities via noncovalent methodology has become one of increasingly significant topics in supramolecular chemistry and showed inventive applications in miscellaneous fields. Herein, we demonstrate that sulfonated crown ether can form very stable host-guest complexes with a series of push-pull-type photosensitizers, eventually leading to the dramatic fluorescence enhancement in visible and near-infrared regions. Meanwhile, severe suppression in singlet oxygen (¹ O₂ ) production is found, mainly due to the higher energy barriers between the excited single and triple states upon host-guest complexation. Moreover, such complexation-induced tuneable ¹ O₂ generation systems has been utilized in adjusting the photochemical oxidation reactions of polycyclic aromatic hydrocarbons (anthracene) and sulfides ((methylthio)benzene) in water. This supramolecularly controlled photooxidation based on the selective molecular binding of crown ether with photosensitizers may provide a feasible and applicable strategy for monitoring and modulating many photocatalysis processes in aqueous phase.

A water-soluble iron-porphyrin complex capable of rescuing CO-poisoned red blood cells

We describe herein a small-molecule platform that exhibits key properties needed by an antidote for CO poisoning. The design features an iron-porphyrin complex with bulky substituents above and below the...

FRET-Based In-Cell Detection of Highly Selective Supramolecular Complexes of meso-Tetraarylporphyrin with Peptide/BODIPY-Modified Per-O-Methyl-β-Cyclodextrins

Artificial supramolecular systems capable of self-assembly and that precisely function in biological media are in high demand. Herein, we demonstrate a highly specific host-guest-pair system that functions in living cells. A per-O-methyl-β-cyclodextrin derivative (R8-B-CD^Me ) bearing both an octaarginine peptide chain and a BODIPY dye was synthesized as a fluorescent intracellular delivery tool. R8-B-CD^Me was efficiently taken up by HeLa cells through both endocytosis and direct transmembrane pathways. R8-B-CD^Me formed a 2 : 1 inclusion complex with tetrakis(4-sulfonatophenyl)porphyrin (TPPS) as a guest molecule in water, from which fluorescence resonance energy transfer (FRET) from R8-B-CD^Me to TPPS was observed. The FRET phenomenon was clearly detected in living cells using confocal microscopy techniques, which revealed that the formed supramolecular R8-B-CD^Me /TPPS complex was maintained within the cells. The R8-B-CD^Me cytotoxicity assay revealed that the addition of TPPS counteracts the strong cytotoxicity (IC₅₀ =16 μM) of the CD cavity due to complexation within the cells. A series of experiments demonstrated the bio-orthogonality of the supramolecular per-O-methyl-β-CD/tetraarylporphyrin host-guest pair in living cells.

Functional Myoglobin Model Composed of a Strapped Porphyrin/Cyclodextrin Supramolecular Complex with an Overhanging COOH That Increases O2/CO Binding Selectivity in Aqueous Solution

A water-soluble strapped iron(III)tetraarylporphyrin (Fe^IIIPor-1) bearing two propylpyridinium groups at the side chains and a carboxylic acid group at the overhanging position of the strap was synthesized to mimic the function of myoglobin with the distal polar functionality in aqueous solution. Fe^IIIPor-1 forms a stable 1:1 inclusion complex with a per-O-methylated β-cyclodextrin dimer having a pyridine linker (Py3OCD), providing a hydrophobic environment and a proximal fifth ligand to stabilize the O₂-complex. The ferrous complex (Fe^IIPorCD-1) binds both O₂ and CO in aqueous solution. The O₂ and CO binding affinities (P_1/2^O2 and P_1/2^CO) and half-life time (t_1/2) of the O₂ complex of Fe^IIPorCD-1 are 6.3 and 0.021 Torr, and 7 h, respectively, at pH 7 and 25 °C. The control compound without the strap structure (Fe^IIPorCD-2) has similar oxygen binding characteristics (P_1/2^O2 = 8.0 Torr), but much higher CO binding affinity (P_1/2^CO = 3.8 × 10^-4 Torr), and longer t_1/2 (30 h). The O₂ and CO kinetics indicate that the strapped structure in Fe^IIPorCD-1 inhibits the entrance of these gaseous ligands into the iron(II) center, as evidenced by lower k_on^O2 and k_on^CO values. Interestingly, the CO complex of Fe^IIPorCD-1 is significantly destabilized (relatively larger k_off^CO), while the k_off^O2 value is much smaller than that of Fe^IIPorCD-2, resulting in significantly increased O₂/CO selectivity (reduced M value, where M = P_1/2^O2/P_1/2^CO = 320) in Fe^IIPorCD-1 compared to Fe^IIPorCD-2 (M = 21000).