HeLa and L929 cells. Transfection efficiency of the vectors was evaluated using p53 plasmid, which demonstrated good transfection in isolated cancer cells (C6 and HeLa)
Nanogels loaded with A. ciniformis extract inhibited cell proliferation and arrested the cell cycle at the G0/G1 phase. Induction of apoptosis occurred in a time‐ and dose‐dependent manner; expression levels of pro‐apoptotic genes were up‐regulated; down‐regulation of anti‐apoptotic and metastatic genes were detected; nanogels exhibited potent anticancer activity against AGS gastric cancer cells
Rahimivand et al. (2020)
Bacterial cellulose + Fe3O4 NPs
Magnetic materials made from tetraaza macrocyclic Schiff base bacterial cellulose ligands with magnetite nanoparticles (Fe3O4 NPs) effectively inhibited the growth of the CT26 tumor models in BALB/c mice
Chaabane et al. (2020)
Clindamycin phosphate‐xanthan gum‐ZnO NPs
NPs applied as topical anti‐inflammatory drug carrier for acne treatment
Karakuş (2019)
Chitin
Silver NPs associated with chitin/Ag nanofibers presented strong antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, and Influenza A virus
Dual‐loaded nanofibers exhibited in vitro antimicrobial activity against two strains of methicillin‐resistant S. aureus (MRSA) and Staphylococcus epidermidis
Calcium alginate/TOBC biomimetic hydrogels loaded with Zn2+ exhibited good mechanical, antimicrobial, and biological properties at Zn2+ concentration of 0.0001 wt%.
Nanofibrous membranes were tested against E. coli and S. aureus and presented good antimicrobial activity with 6.08 and 5.78 log reduction, respectively
Lin et al. (2017)
Chitosan nanofiber
Biocompatible chitosan nanofiber membranes used for bone regeneration in rabbit calvarial defects with healing effect and no evidence of inflammatory reaction
Shin et al. (2005)
Collagen/elastin nanofibers
Nanofibers coated with ECM proteins with good potential for wound dressing and scaffolds for tissue engineering
Biodegradable electrospun nanofibers of PLGA and chitin presented cell adhesion and spreading for normal human keratinocytes, and were good matrices for normal human fibroblasts
Nanofibers based on blends of dextran and PLGA were tested in terms of interaction with dermal fibroblasts considering cell viability, proliferation, attachment, migration, extracellular matrix deposition, and cytoskeleton organization, and the functional gene expressions were characterized, scaffolds with good potential to enhance the healing of chronic or trauma wounds
Metronidazole was loaded in PCL/gelatine, and a sustained release was observed and significantly prevented anaerobic bacteria colonization; cytocompatibility for drug concentrations up to 30%
Xue et al. (2014)
Chitosan‐alginate nanofibers + gentamicin
Chitosan‐alginate nanofibers with 1–3% wt gentamicin significantly enhanced skin regeneration in mice model by stimulating the formation of a thicker dermis, increasing collagen deposition, and increasing the formation of new blood vessels and hair follicles
Bakhsheshi‐Rad et al. (2019)
2.4 Safety of Microbial Biopolymers Used in Nanoscale‐Systems for Therapeutic Applications
Several synthetic polymers are produced from aromatic monomers, mainly bearing a benzene ring. This characteristic often makes them more toxic and less biocompatible, which restrict their applications as biomaterials. The metabolism of benzene (and also some of its derivatives) in mammals and in microorganisms is a subject of study since decades, but its biotransformation and the mechanisms that lead to toxicity are still not fully understood. In mammals and in some microorganisms, the metabolism of benzene and its derivatives occurs through the family of cytochrome P450 (CYP) enzymes, responsible for the insertion of oxygen atoms in these lipophilic compounds aiming at increasing their solubility in aqueous medium (Santos et al. 2017).
In humans, benzene is metabolized mainly in the liver (primary metabolism) and subsequently in the bone marrow (secondary metabolism) (Dougherty et al. 2008; Barata‐Silva et al. 2014). In the first stage of benzene metabolization, the action of a monooxygenase of the cytochrome P450 complex (CYP) is observed, leading to the formation of benzene oxides (epoxy benzene or oxepin), considered reactive. Benzene oxides can covalently bind to proteins and DNA, forming precancerous adducts, or can be metabolized to muconaldehydes and benzoquinones, which are also reactive compounds. The formation of free radicals is also possible, leading to oxidative stress (Figure 2.4) (Chaney and Carlson 1995; Ross 1996; Snyder and Hedli 1996; Monks et al. 2010; Moro et al. 2013; Barata‐Silva et al. 2014).
In later stages of benzene metabolism, the formation of phenolic compounds such as phenol, catechol, and hydroquinone is observed. The toxicity of these compounds, in particular, of hydroquinones, can be highlighted, since they are precursors of myelotoxic compounds and inhibitors of the ribonucleotide reductase, essential for the DNA biosynthesis. Benzoquinones and benzene triol, formed in the bone marrow, can conjugate with sulfates and glucuronic acids, and are capable of forming adducts with DNA generating mutations favoring carcinogenesis processes (Figure 2.4) (Loureiro et al. 2002;
HeLa and L929 cells. Transfection efficiency of the vectors was evaluated using p53 plasmid, which demonstrated good transfection in isolated cancer cells (C6 and HeLa)
