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Biodegradable polycaprolactone-titania nanocomposites: preparation, characterization and antimicrobial properties.

Muñoz-Bonilla A, Cerrada ML, Fernández-García M, Kubacka A, Ferrer M, Fernández-García M - Int J Mol Sci (2013)

Bottom Line: TEM evaluation provides evidence of an excellent nanometric dispersion of the oxide component in the polymeric matrix, with aggregates having an average size well below 100 nm.Presence of these TiO2 nanoparticles induces a nucleant effect during polymer crystallization.The bactericidal behavior has been explained through the analysis of the material optical properties, with a key role played by the creation of new electronic states within the polymer-based nanocomposites.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain. sbonilla@ictp.csic.es.

ABSTRACT
Nanocomposites obtained from the incorporation of synthesized TiO2 nanoparticles (≈10 nm average primary particle size) in different amounts, ranging from 0.5 to 5 wt.%, into a biodegradable polycaprolactone matrix are achieved via a straightforward and commercial melting processing. The resulting nanocomposites have been structurally and thermally characterized by transmission electron microscopy (TEM), wide/small angle X-ray diffraction (WAXS/SAXS, respectively) and differential scanning calorimetry (DSC). TEM evaluation provides evidence of an excellent nanometric dispersion of the oxide component in the polymeric matrix, with aggregates having an average size well below 100 nm. Presence of these TiO2 nanoparticles induces a nucleant effect during polymer crystallization. Moreover, the antimicrobial activity of nanocomposites has been tested using both UV and visible light against Gram-negative Escherichia coli bacteria and Gram-positive Staphylococcus aureus. The bactericidal behavior has been explained through the analysis of the material optical properties, with a key role played by the creation of new electronic states within the polymer-based nanocomposites.

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UV-visible absorption spectra of the PCL component and PCL-TiO2-x nanocomposite materials.
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f6-ijms-14-09249: UV-visible absorption spectra of the PCL component and PCL-TiO2-x nanocomposite materials.

Mentions: The presence of TiO2 in these nanocomposites has revealed non-significant changes in the PCL crystalline structure, phase transitions and thermal stability. Nevertheless, a more critical aspect is the knowledge of the effect of TiO2 on their optical properties, since they are rather important considering the need of efficient light absorption by TiO2 to become a biocidal material. The spectrum of the TiO2 component has been reported elsewhere [8,9,41] and is characterized by a band gap of 3.2 eV (ca. 380 nm). The UV-visible spectra of the nanocomposites and reference PCL are displayed in Figure 6. The PCL polymeric component shows a weak shoulder at 250–300 nm, which is attributed to the n→π* transition of the ester carbonyl. Incorporation of the inorganic component to the PCL polymeric matrix leads to important changes in the absorption profile. Inorganic nanoparticle loadings below 2 wt.% mainly alter the PCL spectrum by enhancing the absorbance on the visible region. Changes are more dramatic at 5 wt.% content and a new, broad absorption feature between 330 and 400 nm becomes evident. Therefore, presence of the inorganic component has two effects: enhancement of the signal intensity in the UV-A and visible ranges and indication of the characteristic oxide band gap. This last feature is only clearly distinguishable in the sample with the highest TiO2 content (PCL-TiO2-5). Light interaction with the nanocomposite materials would thus display a complex behavior, with an improvement of the absorption power of the nanocomposite that is not easily ascribed to any of the bare components, this being particularly true in the visible region because neither of them absorb light.


Biodegradable polycaprolactone-titania nanocomposites: preparation, characterization and antimicrobial properties.

Muñoz-Bonilla A, Cerrada ML, Fernández-García M, Kubacka A, Ferrer M, Fernández-García M - Int J Mol Sci (2013)

UV-visible absorption spectra of the PCL component and PCL-TiO2-x nanocomposite materials.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3676781&req=5

f6-ijms-14-09249: UV-visible absorption spectra of the PCL component and PCL-TiO2-x nanocomposite materials.
Mentions: The presence of TiO2 in these nanocomposites has revealed non-significant changes in the PCL crystalline structure, phase transitions and thermal stability. Nevertheless, a more critical aspect is the knowledge of the effect of TiO2 on their optical properties, since they are rather important considering the need of efficient light absorption by TiO2 to become a biocidal material. The spectrum of the TiO2 component has been reported elsewhere [8,9,41] and is characterized by a band gap of 3.2 eV (ca. 380 nm). The UV-visible spectra of the nanocomposites and reference PCL are displayed in Figure 6. The PCL polymeric component shows a weak shoulder at 250–300 nm, which is attributed to the n→π* transition of the ester carbonyl. Incorporation of the inorganic component to the PCL polymeric matrix leads to important changes in the absorption profile. Inorganic nanoparticle loadings below 2 wt.% mainly alter the PCL spectrum by enhancing the absorbance on the visible region. Changes are more dramatic at 5 wt.% content and a new, broad absorption feature between 330 and 400 nm becomes evident. Therefore, presence of the inorganic component has two effects: enhancement of the signal intensity in the UV-A and visible ranges and indication of the characteristic oxide band gap. This last feature is only clearly distinguishable in the sample with the highest TiO2 content (PCL-TiO2-5). Light interaction with the nanocomposite materials would thus display a complex behavior, with an improvement of the absorption power of the nanocomposite that is not easily ascribed to any of the bare components, this being particularly true in the visible region because neither of them absorb light.

Bottom Line: TEM evaluation provides evidence of an excellent nanometric dispersion of the oxide component in the polymeric matrix, with aggregates having an average size well below 100 nm.Presence of these TiO2 nanoparticles induces a nucleant effect during polymer crystallization.The bactericidal behavior has been explained through the analysis of the material optical properties, with a key role played by the creation of new electronic states within the polymer-based nanocomposites.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), C/Juan de la Cierva 3, 28006 Madrid, Spain. sbonilla@ictp.csic.es.

ABSTRACT
Nanocomposites obtained from the incorporation of synthesized TiO2 nanoparticles (≈10 nm average primary particle size) in different amounts, ranging from 0.5 to 5 wt.%, into a biodegradable polycaprolactone matrix are achieved via a straightforward and commercial melting processing. The resulting nanocomposites have been structurally and thermally characterized by transmission electron microscopy (TEM), wide/small angle X-ray diffraction (WAXS/SAXS, respectively) and differential scanning calorimetry (DSC). TEM evaluation provides evidence of an excellent nanometric dispersion of the oxide component in the polymeric matrix, with aggregates having an average size well below 100 nm. Presence of these TiO2 nanoparticles induces a nucleant effect during polymer crystallization. Moreover, the antimicrobial activity of nanocomposites has been tested using both UV and visible light against Gram-negative Escherichia coli bacteria and Gram-positive Staphylococcus aureus. The bactericidal behavior has been explained through the analysis of the material optical properties, with a key role played by the creation of new electronic states within the polymer-based nanocomposites.

Show MeSH
Related in: MedlinePlus