۱- INTRODUCTION

۲- EXPERIMENTAL

۳- RESULTS AND DISCUSSION

۴- CONCLUSIONS

REFERENCES

Abstract

Super porous gum Arabic (GA) cryogels were synthesized by crosslinking of natural GA with divinyl sulfone at cryogenic conditions, −۲۰°C for potential biomedical applications. Humic acid (HA) nanoparticles were also prepared by using degradable and biocompatible crosslinkers such as trimethylolpropane triglycidyl ether, poly(ethylene glycol) diglycidyl ether, and trisodium trimetaphosphate in a single step and then entrapped within GA cryogel network as GA/HA particle cryogel. Furthermore, GA/HA cryogel was used as a template for Ag, Cu, and Fe nanoparticle preparation, and their antimicrobial properties were tested against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis strains. The minimum inhibition concentration values of Ag and Cu nanoparticle‐loaded GA/HA cryogel composites were determined as 10 mg mL−۱٫ Furthermore, the blood compatibility tests such as hemolysis and blood clotting indexes were determined for GA cryogels and found to be more compatible with 0.08 ± ۰٫۰۱% hemolysis and 89.4 ± ۶٫۱ blood clotting values, whereas the hemolysis of the Ag, Cu, and Fe nanoparticle‐loaded GA/HA Ag, Cu, and Fe metal nanoparticle cryogel composites decreased in the order of Fe > Cu > Ag nanoparticles.

Introduction

Humic acid (HA) is a natural macromolecule mainly including phenolic, carboxylic acid, quinone, enolic, and ether functional groups. It can be obtained from natural sources such as terrestrial soil, natural water, and sediment.1 Humic acid has many uses: In cosmetic, pharmaceutical, and medicinal applications, it can be used for wound healing, cancer therapy, drug carrier, and prion disease therapy because of antimutogenic/desmutogenic,2 antibacterial,3 antifungal, antioxidant,4 antiinflammatory, and antiestrogen1,5 and antiviral activities that are related to its phenolic, carboxylic, and quinone functional groups into the structures. Previously, the crosslinked HA particle synthesis was reported for the first time by using different crosslinkers such as divinyl sulfone (DVS), adipoyl chloride, and gluteraldehyde and utilized in environmental applications.6 In this study, HA particles were prepared by using epoxy and phosphate groups containing crosslinkers such as trimethylolpropane triglycidyl ether (TMPGDE), poly(ethylene glycol) diglycidyl ether (PEGGE), and trisodium trimetaphosphate (STMP) as more biocompatible and biodegradable structure in comparison with the previously reported ones. Over the last 2 decades, preparing 2 different polymers has attracted great attention in material science and technology due to the combination of properties of both materials in 1 polymer network with potentially new and synergetic effects.9,10 Lately, cryogel networks are of great interest for a wide range of biomedical applications such as separation and immobilization of cell,11,12 enzyme, or biomacromolecules; drug‐delivery purposes13; and tissue engineering.14 Cryogels possess many superior properties in comparison with conventional hydrogel because of their low density, high and interconnected porosity, and higher surface areas.15 In the literature, different types of natural‐based polymers such as hyaluronic acid, chondroitin sulfate,16 agarose, chitosan, silk‐fibroin,11 gelatin,17 alginate, cellulose,18 rubber, and DNA‐derived cryogels have been reported as versatile biomaterials for different potential applications.