The fabrication of biomimetic catalysts as substituents for enzymes is of critical interest in the field due to the problems associated with the extraction, purification, and storage of enzymes in sensing applications. Of these mimetics, hemin/coordination polymer‐based nanocomposites, mainly hemin/metal–organic frameworks (MOF), have been developed for various biosensing applications because of the unique properties of each component, while trying to mimic the normal biological functions of heme within the protein milieu of enzymes. This critical review first discusses the different catalytic functions of heme in the body in the form of enzyme/protein structures. The properties of hemin dimerization are then elucidated with the supposed models of hemin oxidation. After that, the progress in the fabrication of hemin/MOF nanocomposites for the sensing of diverse biological molecules is discussed. Finally, the challenges in developing this type of composites are examined as well as possible proposals for future directions to enhance the sensing performance in this field further.

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Polyelectrolyte complexes represent a special class of polymeric compounds consisting of stoichiometric equivalents of oppositely charged polyions interacting together spontaneously to yield a complex in different forms. The present study aimed at preparing coacervates of alginate and chitosan polymers ready for casting as wound dressing films. This was based on controlling the pH of solutions and the reactions speed through controlling the rate of mixing of the polymers solutions together without using any water-miscible solvents. Alginate was modified with radiation and oxidation, and the interactions of the resulting chains and chitosan chains were tested with FTIR spectroscopy and scanning of the resulting films with SEM. This work showed the ability to prepare a complex of highly connected polymeric chains for further biomedical applications. This complex in the form of hydrogel could enhance the proliferation of cells in vitro and the healing efficiency with accelerating the wound closure rate as evidenced through the histological observations.

The extracellular matrix (ECM) dynamics in tumour tissue are deregulated compared to the ECM in healthy tissue along with disorganized architecture and irregular behaviour of the residing cells. Nitric oxide (NO) as a pleiotropic molecule exerts different effects on the components of the ECM driving or inhibiting augmented angiogenesis and tumour progression and tumour cell proliferation and metastasis. These effects rely on the concentration of NO within the tumour tissue, the nature of the surrounding microenvironment and the sensitivity of resident cells to NO. In this review article, we summarize the recent findings on the correlation between the levels of NO and the ECM components towards the modulation of tumour angiogenesis in different types of cancers. These are discussed principally in the context of how NO modulates the expression of ECM proteins resulting in either the promotion or inhibition of tumour growth via tumour angiogenesis. Furthermore, the regulatory effects of individual ECM components on the expression of the NO synthase enzymes and NO production were reviewed. These findings support the current efforts for developing effective therapeutics for cancers.

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