“Pointsource” Delivery of a Photosensitizer Drug and Singlet Oxygen: Eradication of Glioma Cells In Vitro

Abstract

We describe a pointsource sensitizer-tipped microoptic device for the eradication of glioma U87 cells. The device has a mesoporous fluorinated silica tip which emits singlet oxygen molecules and small quantities of pheophorbide sensitizer for additional production of singlet oxygen in the immediate vicinity. The results show that the device surges in sensitizer release and photokilling with higher rates about midway through the reaction. This was attributed to a self-amplified autocatalytic reaction where released sensitizer in the extra-cellular matrix provides positive feedback to assist in the release of additional sensitizer. The photokilling of the glioma cells was analyzed by global toxicity and live/dead assays, where a killing radius around the tip with ~0.3 mm precision was achieved. The implication of these results for a new PDT tool of hard-to-resect tumors, e.g. in the brain, is discussed.

Synthesis of a poly(ethylene glycol) galloyl sensitizer tip for an ’all‐in‐one' photodynamic device

“…Because of the need to further advance the pointsource PDT technique , a photocleavable triPEG‐galloyl pheophorbide silica 1 was designed and synthesized. Unlike 2 and 3 that required each of the three PEG groups to be introduced one at a time, 1 had the three PEG groups introduced in one‐step with a galloyl substituent.…”

“…Eradication of residual tumor cells is a daunting challenge to surgeons, one of the problems is accurately marking tumor margins. Because the field urgently needs further advances in intraoperative settings, development of a pointsource PDT implement was sought to reduce or eliminate problems in precise sterilization of surgical margins. Pointsource PDT offers simultaneous delivery of oxygen, light, and sensitizer to the tumor site, creating a highly‐localized killing zone.…”

Photochemical behavior of biosupramolecular assemblies of photosensitizers, cucurbit[n]urils and albumins

“…11 Recent work on DDSs involving photoactive drugs include polymeric nanoparticles, [12][13][14][15] calcium carbonate microparticles, 16 graphene oxide nanosheets, 17 photo-responsive nanocarriers, 18,19 and novel optical fibers which can deliver both the photoactive drug and/or only singlet oxygen. [20][21][22] In spite of the many varieties of DDSs being studied, few of them are being marketed to date. 6 Albumin conjugates have been investigated extensively as drug carriers over the last decade, [23][24][25] and constitute one of the examples of DDSs that have effectively reached the public.…”

Photoactive Fluoropolymer Surfaces That Release Sensitizer Drug Molecules

“…The fluoropolymers could be shaped into device tips to discharge controlled sensitizer and 1 O 2 quantities for tissue repair 83,84 or pointsource photodynamic therapy 85 in vivo . The fluorinated materials provide intriguing possibilities for generating new types of device tips for manual precision in singlet oxygen delivery.…”