Superparamagnetic biobased poly(thioether‐ester) via thiol‐ene polymerization in miniemulsion for hyperthermia

Abstract

Thiol-ene polymerization has been pointed out as a promising technique to produce biobased polymers for biomedical applications due to its advantages, including mild conditions and rapid reaction rates without the formation of byproducts. Therefore, in this study different concentrations of magnetic nanoparticles (MNPs) were incorporated in poly(thioether-ester) (PTEE) nanoparticles by thiol-ene miniemulsion polymerization of biobased monomers to form both linear and branched cross-linked polymers. Loading efficiencies up to approximately 95% (thermogravimetric analysis) of the MNPs within the polymer matrix were obtained. In addition, the substitution of the dithiol 1,4-butanedithiol (64.2%) for the tetrathiol PTEMP (95.8%), increased the encapsulation efficiency by about 30%. Hybrid nanoparticles presented average mean diameters between 95 and260 nm with polydispersity index between 0.13 and 0.42 by DLS, negative zeta potentials around −45 mV and superparamagnetic behavior. The hyperthermia assays performed on breast cells (MDA-MB 231) have shown that the cell death was dependent on the exposure time to the AC magnetic field and the reduction in cell viability was approximately 35%. These results demonstrated the production of superparamagnetic PTEE nanoparticles via thiol-ene polymerization and highlight the promising application of these biobased materials for cancer treatment by hyperthermia.

Evaluation of the in vivo acute toxicity of poly(thioether‐ester) and superparamagnetic poly(thioether‐ester) nanoparticles obtained by thiol‐ene miniemulsion polymerization

“…The MNPs synthesis was performed according to the method used by Feuser et al 14 The syntheses of the renewable monomer, 1,3-propylene diundec-10-enoate, and of the PTEe nanoparticles via miniemulsion polymerization were performed as described by Cardoso et al 18 The material was lyophilized for further use without prior cleaning/purification. The incorporation of the MNPs was also performed via miniemulsion polymerization, as described previously by Santos et al 25 The total concentration of MNPs in the PTEe nanoparticles was of 10 wt %. The material was centrifuged (10,000 rpm/30 min) and washed three times for further use.…”

“…PTEe and PTEe-MNPs nanoparticles at a concentration of 40 mg/kg were administered IP. The choice of the 40 mg/kg dose was based on in vitro results described in a previous work 8,17,25,26 of the group, as well as on the literature 12 . The administration was 24 hr after the last injection, single dose, the mice were euthanized by decapitation, and the tissue was surgically removed, processed, and stored in a freezer at À80 C until further analysis.…”

“…In this study, the cytotoxicity was confirmed in human cervical cancer (HeLa) cells by hyperthermia. Despite the several in vitro studies reported in the literature of polymeric nanoparticles obtained by thiol-ene polymerization, 18,23,25 in vivo studies are fundamental to verify further the biocompatibility of the material. Thus, in the present study, PTEe and PTEe-MNPs nanoparticles were administered intraperitoneally (IP), at concentration of 40 mg/kg in mice, in which behavioral and biochemical parameters were evaluated to verify the in vivo acute toxicity.…”

Droplet nucleation in miniemulsion thiol–ene step photopolymerization

“…12 However, unlike thiol-ene photopolymers, the share hold by thiol-ene latexes has remained limited, and no commercial product has emerged yet. 13,14 The main examples result from a miniemulsion photopolymerization, [15][16][17][18][19][20][21][22][23][24] and to a less extent, dispersion 25,26 and emulsion 12,27 (photo)polymerizations. Suspension photopolymerization has been also described, [28][29][30][31][32] but this process does not result in polymer colloids (average particle diameter < 1 µm), but in micrometre solid beads (0.1 -10 mm).…”

“…The most used process in this field is miniemulsion thiolene polymerization. [15][16][17][18][19][20][21][22][23][24] Involving smaller and therefore less scattering monomer droplets (50 -500 nm) than an emulsion polymerization, it has the added advantage of imparting greater radiation penetration within the reactor. In addition, Please do not adjust margins Please do not adjust margins the desired particle nucleation mode occurs via radical capture into the monomer droplets, subsequently converted into polymer particles.…”