Amine modification of thermally carbonized porous silicon with silane coupling chemistry

Ermei Mäkilä, Luis M. Bimbo, Martti Kaasalainen, Barbara Herranz, Anu J. Airaksinen, Markku Heinonen, Edwin Kukk, Jouni Hirvonen, Hélder A. Santos, Jarno Salonen

Research output: Contribution to journalArticle

75 Citations (Scopus)

Abstract

Thermally carbonized porous silicon (TCPSi) microparticles were chemically modified with organofunctional alkoxysilane molecules using a silanization process. Before the silane coupling, the TCPSi surface was activated by immersion in hydrofluoric acid (HF). Instead of regeneration of the silicon hydride species, the HF immersion of silicon carbide structure forms a silanol termination (Si-OH) on the surface required for silanization. Subsequent functionalization with 3-aminopropyltriethoxysilane provides the surface with an amine (-NH(2)) termination, while the SiC-type layer significantly stabilizes the functionalized structure both mechanically and chemically. The presence of terminal amine groups was verified with FTIR, XPS, CHN analysis, and electrophoretic mobility measurements. The overall effects of the silanization to the morphological properties of the initial TCPSi were analyzed and they were found to be very limited, making the treatment effects highly predictable. The maximum obtained number of amine groups on the surface was calculated to be 1.6 groups/nm(2), corresponding to 79% surface coverage. The availability of the amine groups for further biofunctionalization was confirmed by successful biotinylation. The isoelectric point (IEP) of amine-terminated TCPSi was measured to be at pH 7.7, as opposed to pH 2.6 for untreated TCPSi. The effects of the surface amine termination on the cell viability of Caco-2 and HT-29 cells and on the in vitro fenofibrate release profiles were also assessed. The results indicated that the surface modification did not alter the loading of the drug inside the pores and also retained the beneficial enhanced dissolution characteristics similar to TCPSi. Cellular viability studies also showed that the surface modification had only a limited effect on the biocompatibility of the PSi.

LanguageEnglish
Pages14045-14054
Number of pages10
JournalLangmuir
Volume28
Issue number39
Early online date11 Sep 2012
DOIs
Publication statusPublished - 2 Oct 2012
Externally publishedYes

Fingerprint

Silanes
Porous silicon
Silicon
porous silicon
silanes
Amines
amines
chemistry
Hydrofluoric Acid
Hydrofluoric acid
Immersion
Surface treatment
hydrofluoric acid
viability
submerging
Fenofibrate
Electrophoretic mobility
Biotinylation
HT29 Cells
Biocompatibility

Keywords

  • amines
  • porosity
  • silanes
  • silicon
  • surface properties
  • temperature
  • nanoparticles

Cite this

Mäkilä, E., Bimbo, L. M., Kaasalainen, M., Herranz, B., Airaksinen, A. J., Heinonen, M., ... Salonen, J. (2012). Amine modification of thermally carbonized porous silicon with silane coupling chemistry. Langmuir, 28(39), 14045-14054. https://doi.org/10.1021/la303091k
Mäkilä, Ermei ; Bimbo, Luis M. ; Kaasalainen, Martti ; Herranz, Barbara ; Airaksinen, Anu J. ; Heinonen, Markku ; Kukk, Edwin ; Hirvonen, Jouni ; Santos, Hélder A. ; Salonen, Jarno. / Amine modification of thermally carbonized porous silicon with silane coupling chemistry. In: Langmuir. 2012 ; Vol. 28, No. 39. pp. 14045-14054.
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Mäkilä, E, Bimbo, LM, Kaasalainen, M, Herranz, B, Airaksinen, AJ, Heinonen, M, Kukk, E, Hirvonen, J, Santos, HA & Salonen, J 2012, 'Amine modification of thermally carbonized porous silicon with silane coupling chemistry' Langmuir, vol. 28, no. 39, pp. 14045-14054. https://doi.org/10.1021/la303091k

Amine modification of thermally carbonized porous silicon with silane coupling chemistry. / Mäkilä, Ermei; Bimbo, Luis M.; Kaasalainen, Martti; Herranz, Barbara; Airaksinen, Anu J.; Heinonen, Markku; Kukk, Edwin; Hirvonen, Jouni; Santos, Hélder A.; Salonen, Jarno.

In: Langmuir, Vol. 28, No. 39, 02.10.2012, p. 14045-14054.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Amine modification of thermally carbonized porous silicon with silane coupling chemistry

AU - Mäkilä, Ermei

AU - Bimbo, Luis M.

AU - Kaasalainen, Martti

AU - Herranz, Barbara

AU - Airaksinen, Anu J.

AU - Heinonen, Markku

AU - Kukk, Edwin

AU - Hirvonen, Jouni

AU - Santos, Hélder A.

AU - Salonen, Jarno

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N2 - Thermally carbonized porous silicon (TCPSi) microparticles were chemically modified with organofunctional alkoxysilane molecules using a silanization process. Before the silane coupling, the TCPSi surface was activated by immersion in hydrofluoric acid (HF). Instead of regeneration of the silicon hydride species, the HF immersion of silicon carbide structure forms a silanol termination (Si-OH) on the surface required for silanization. Subsequent functionalization with 3-aminopropyltriethoxysilane provides the surface with an amine (-NH(2)) termination, while the SiC-type layer significantly stabilizes the functionalized structure both mechanically and chemically. The presence of terminal amine groups was verified with FTIR, XPS, CHN analysis, and electrophoretic mobility measurements. The overall effects of the silanization to the morphological properties of the initial TCPSi were analyzed and they were found to be very limited, making the treatment effects highly predictable. The maximum obtained number of amine groups on the surface was calculated to be 1.6 groups/nm(2), corresponding to 79% surface coverage. The availability of the amine groups for further biofunctionalization was confirmed by successful biotinylation. The isoelectric point (IEP) of amine-terminated TCPSi was measured to be at pH 7.7, as opposed to pH 2.6 for untreated TCPSi. The effects of the surface amine termination on the cell viability of Caco-2 and HT-29 cells and on the in vitro fenofibrate release profiles were also assessed. The results indicated that the surface modification did not alter the loading of the drug inside the pores and also retained the beneficial enhanced dissolution characteristics similar to TCPSi. Cellular viability studies also showed that the surface modification had only a limited effect on the biocompatibility of the PSi.

AB - Thermally carbonized porous silicon (TCPSi) microparticles were chemically modified with organofunctional alkoxysilane molecules using a silanization process. Before the silane coupling, the TCPSi surface was activated by immersion in hydrofluoric acid (HF). Instead of regeneration of the silicon hydride species, the HF immersion of silicon carbide structure forms a silanol termination (Si-OH) on the surface required for silanization. Subsequent functionalization with 3-aminopropyltriethoxysilane provides the surface with an amine (-NH(2)) termination, while the SiC-type layer significantly stabilizes the functionalized structure both mechanically and chemically. The presence of terminal amine groups was verified with FTIR, XPS, CHN analysis, and electrophoretic mobility measurements. The overall effects of the silanization to the morphological properties of the initial TCPSi were analyzed and they were found to be very limited, making the treatment effects highly predictable. The maximum obtained number of amine groups on the surface was calculated to be 1.6 groups/nm(2), corresponding to 79% surface coverage. The availability of the amine groups for further biofunctionalization was confirmed by successful biotinylation. The isoelectric point (IEP) of amine-terminated TCPSi was measured to be at pH 7.7, as opposed to pH 2.6 for untreated TCPSi. The effects of the surface amine termination on the cell viability of Caco-2 and HT-29 cells and on the in vitro fenofibrate release profiles were also assessed. The results indicated that the surface modification did not alter the loading of the drug inside the pores and also retained the beneficial enhanced dissolution characteristics similar to TCPSi. Cellular viability studies also showed that the surface modification had only a limited effect on the biocompatibility of the PSi.

KW - amines

KW - porosity

KW - silanes

KW - silicon

KW - surface properties

KW - temperature

KW - nanoparticles

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DO - 10.1021/la303091k

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SP - 14045

EP - 14054

JO - Langmuir

T2 - Langmuir

JF - Langmuir

SN - 0743-7463

IS - 39

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Mäkilä E, Bimbo LM, Kaasalainen M, Herranz B, Airaksinen AJ, Heinonen M et al. Amine modification of thermally carbonized porous silicon with silane coupling chemistry. Langmuir. 2012 Oct 2;28(39):14045-14054. https://doi.org/10.1021/la303091k