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Enhanced Phototherapy Activity by Employing a Nanosilica-Coumarin–Acifluorfen Conjugate as the Supplementary Light Source Generator
journal contribution
posted on 2019-10-17, 17:38 authored by Junfan Niu, Jingyue Tang, Gang Tang, Zhiyuan Zhou, Rong Tang, Jiale Yang, Na Jiang, Jianqiang Li, Yongsong CaoPhotosensitizers
need to be activated
by external light to achieve phototherapy. However, unsatisfactory
tissue penetration of light and uncontrollable light intensity limit
their application. To overcome the limitations, a novel fluorescent
conjugate was developed by conjugating coumarin-functionalized nanosilica
with acifluorfen to emit fluorescence as the supplementary light to
activate protoporphyrin IX (PpIX, a photosensitizer in plant cell
that can be induced by acifluorfen) for enhancing phototherapy activity.
The results showed that the obtained conjugate could obviously increase
the singlet oxygen yield of PpIX and exhibited remarkable photodynamic
herbicidal activity against Amaranthus retroflexus. Under low light intensity, its photodynamic herbicidal activity
was five to six times higher than that of acifluorfen sodium salt.
The conjugate could move upward and downward freely in vascular system
of Brassica juncea seedlings and significantly
reduced the cytotoxicity of acifluorfen. Moreover, the conjugate was
proved to be safe to soybean at concentrations of 200–800 mg/L
of acifluorfen. This study gives a novel drug delivery system with
the potential of reducing light-dependent drug dosage and harm to
nontarget organisms and offers a way to use fluorescent emission as
the supplementary light to enhance the phototherapy activity of photosensitizers.