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TiO 2 nanotube platforms for smart drug delivery: a review

View Article: PubMed Central - PubMed

ABSTRACT

Titania nanotube (TNT) arrays are recognized as promising materials for localized drug delivery implants because of their excellent properties and facile preparation process. This review highlights the concept of localized drug delivery systems based on TNTs, considering their outstanding biocompatibility in a series of ex vivo and in vivo studies. Considering the safety of TNT implants in the host body, studies of the biocompatibility present significant importance for the clinical application of TNT implants. Toward smart TNT platforms for sustainable drug delivery, several advanced approaches were presented in this review, including controlled release triggered by temperature, light, radiofrequency magnetism, and ultrasonic stimulation. Moreover, TNT implants used in medical therapy have been demonstrated by various examples including dentistry, orthopedic implants, cardiovascular stents, and so on. Finally, a future perspective of TNTs for clinical applications is provided.

No MeSH data available.


Schematic illustration of temperature-controlled stimulus to trigger drug release based on TNTs.Notes: (A) Overview of drug-loaded TNTs with hydrogel coating; (B) drug release profiles from TNTs. Reprinted from Cai K, Jiang F, Luo Z, Chen X. Temperature-responsive controlled drug delivery system based on titanium nanotubes. Adv Eng Mater. 2010;12:B565–B570,78 with permission from John Wiley and Sons.Abbreviations: AAm, acrylamide; LCST, lower critical solution temperature; NIPAAm, N-isopropylacrylamide; TNT, titania nanotube.
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f5-ijn-11-4819: Schematic illustration of temperature-controlled stimulus to trigger drug release based on TNTs.Notes: (A) Overview of drug-loaded TNTs with hydrogel coating; (B) drug release profiles from TNTs. Reprinted from Cai K, Jiang F, Luo Z, Chen X. Temperature-responsive controlled drug delivery system based on titanium nanotubes. Adv Eng Mater. 2010;12:B565–B570,78 with permission from John Wiley and Sons.Abbreviations: AAm, acrylamide; LCST, lower critical solution temperature; NIPAAm, N-isopropylacrylamide; TNT, titania nanotube.

Mentions: For temperature-sensitive drug delivery based on TNTs, temperature-responsive polymers were explored to decorate TNT implants. Cai et al fabricated a temperature-sensitive drug delivery system based on TNTs by using vitamin B2 as a model drug and explored kinetics of controlled drug release from TNTs with temperature-responsive trigger.78 In their study, the hydrogel layer formed from poly(N-isopropylacrylamide) (PNIPAAm) and poly(acrylamide) (PAAm) was used as a cap that was coated on the surface of TNT layers for sealing the open nanotubes. The PNIPAAm/PAAm composite hydrogel presents a highly water swollen state that prevents the drug release from TNTs when the surrounding temperature is below its lower critical solution temperature, whereas the composite hydrogel is in a collapsing state to allow drug releasing from TNTs once the temperature is higher than the lower critical solution temperature of the composite hydrogel, as shown in Figure 5A. The drug release profile of pure TNTs at 25°C is higher than that of hydrogel-coated TNTs under the same condition, since there is no barrier to block the drug release at all. When the temperature increases to ~38°C due to the inflammatory reaction, hydrogel-coated TNTs show much higher release profiles than that of hydrogel-coated TNTs at 25°C as shown in Figure 5B. This is because 38°C is higher than the lower critical solution temperature of composite hydrogel; hence, the composite hydrogel was in a collapsing state to allow drug release from TNTs.


TiO 2 nanotube platforms for smart drug delivery: a review
Schematic illustration of temperature-controlled stimulus to trigger drug release based on TNTs.Notes: (A) Overview of drug-loaded TNTs with hydrogel coating; (B) drug release profiles from TNTs. Reprinted from Cai K, Jiang F, Luo Z, Chen X. Temperature-responsive controlled drug delivery system based on titanium nanotubes. Adv Eng Mater. 2010;12:B565–B570,78 with permission from John Wiley and Sons.Abbreviations: AAm, acrylamide; LCST, lower critical solution temperature; NIPAAm, N-isopropylacrylamide; TNT, titania nanotube.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC5036548&req=5

f5-ijn-11-4819: Schematic illustration of temperature-controlled stimulus to trigger drug release based on TNTs.Notes: (A) Overview of drug-loaded TNTs with hydrogel coating; (B) drug release profiles from TNTs. Reprinted from Cai K, Jiang F, Luo Z, Chen X. Temperature-responsive controlled drug delivery system based on titanium nanotubes. Adv Eng Mater. 2010;12:B565–B570,78 with permission from John Wiley and Sons.Abbreviations: AAm, acrylamide; LCST, lower critical solution temperature; NIPAAm, N-isopropylacrylamide; TNT, titania nanotube.
Mentions: For temperature-sensitive drug delivery based on TNTs, temperature-responsive polymers were explored to decorate TNT implants. Cai et al fabricated a temperature-sensitive drug delivery system based on TNTs by using vitamin B2 as a model drug and explored kinetics of controlled drug release from TNTs with temperature-responsive trigger.78 In their study, the hydrogel layer formed from poly(N-isopropylacrylamide) (PNIPAAm) and poly(acrylamide) (PAAm) was used as a cap that was coated on the surface of TNT layers for sealing the open nanotubes. The PNIPAAm/PAAm composite hydrogel presents a highly water swollen state that prevents the drug release from TNTs when the surrounding temperature is below its lower critical solution temperature, whereas the composite hydrogel is in a collapsing state to allow drug releasing from TNTs once the temperature is higher than the lower critical solution temperature of the composite hydrogel, as shown in Figure 5A. The drug release profile of pure TNTs at 25°C is higher than that of hydrogel-coated TNTs under the same condition, since there is no barrier to block the drug release at all. When the temperature increases to ~38°C due to the inflammatory reaction, hydrogel-coated TNTs show much higher release profiles than that of hydrogel-coated TNTs at 25°C as shown in Figure 5B. This is because 38°C is higher than the lower critical solution temperature of composite hydrogel; hence, the composite hydrogel was in a collapsing state to allow drug release from TNTs.

View Article: PubMed Central - PubMed

ABSTRACT

Titania nanotube (TNT) arrays are recognized as promising materials for localized drug delivery implants because of their excellent properties and facile preparation process. This review highlights the concept of localized drug delivery systems based on TNTs, considering their outstanding biocompatibility in a series of ex vivo and in vivo studies. Considering the safety of TNT implants in the host body, studies of the biocompatibility present significant importance for the clinical application of TNT implants. Toward smart TNT platforms for sustainable drug delivery, several advanced approaches were presented in this review, including controlled release triggered by temperature, light, radiofrequency magnetism, and ultrasonic stimulation. Moreover, TNT implants used in medical therapy have been demonstrated by various examples including dentistry, orthopedic implants, cardiovascular stents, and so on. Finally, a future perspective of TNTs for clinical applications is provided.

No MeSH data available.