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Comparative Study on Photodynamic Activation of Ortho-Toluidine Blue and Methylene Blue Loaded Mesoporous Silica

Ashka Amin1, Deepali V Kaduskar1

  • 1Department of Pharmaceutics, Shobhaben Pratapbhai Patel School of Pharmacy and Technology Management, SVKM's NMIMS, Vile Parle (West), Maharashtra, India.

Recent Patents on Drug Delivery & Formulation
|June 29, 2018
PubMed
Abstract

Insights

Antimicrobial photodynamic therapy using methylene blue or ortho-toluidine blue loaded mesoporous silica nanoparticles effectively inactivated bacteria. This novel approach shows promise as an alternative to conventional antibiotics.

Area of Science:

  • Nanotechnology
  • Photochemistry
  • Microbiology

Background:

  • Increasing antibiotic resistance necessitates alternative antimicrobial strategies.
  • Antimicrobial photodynamic therapy (aPDT) offers a promising alternative to conventional antibiotics.
  • Mesoporous silica nanoparticles (MSN) are being explored for their antimicrobial applications.

Purpose of the Study:

  • To synthesize and characterize photosensitizer-loaded MSN for aPDT.
  • To evaluate the antimicrobial efficacy of MSN loaded with methylene blue (MB) and ortho-toluidine blue (O-TB) against pathogenic bacteria.
  • To investigate the role of light exposure and MSN functionalization in aPDT.

Main Methods:

  • MSN were synthesized via Sol-Gel method and functionalized with APTES.
  • Methylene blue (MB) and ortho-toluidine blue (O-TB) were used as photosensitizers.
  • Antimicrobial activity was assessed using standard assays against E. coli, S. aureus, and P. aeruginosa after red light irradiation.

Main Results:

  • Successful adsorption of MB and O-TB onto APTES-functionalized MSN was confirmed.
  • Irradiation of photosensitizer-loaded MSN significantly enhanced the zone of inhibition compared to non-irradiated samples.
  • O-TB loaded MSN demonstrated higher antimicrobial activity than MB loaded MSN.

Conclusions:

  • APTES-functionalized MSN loaded with MB and O-TB are effective in inactivating E. coli, P. aeruginosa, and S. aureus via aPDT.
  • The high surface area and porous structure of MSN contribute to their efficacy in aPDT.
  • APTES functionalization enhances photosensitizer loading capacity and antimicrobial activity.
Keywords:
Mesoporous silica nanoparticlesantimicrobial photodynamic therapygram negative microorganismsmethylene blueortho-toluidine blue.

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