Silicon Nanoparticles: a versatile fluorescence material for biological and technological applications

GONZALEZ, MÓNICA C.

Easton Collegue, Massachusetts

Conferencia; Gordon Research Conferences. Photochemistry for the Future; 2015

Gordon Research Conferences

Biocompatible and biodegradable silicon nanoparticles of 1−5 nm size combine photoluminescence emission with the capability for singlet oxygen (1O2) and superoxide (O2?−) generation. These properties provide silicon nanoparticles (SiNPs) potential capacity as photosensitizers in Photo Dynamic Therapy. SiNPs are also capable of increasing the yield of O2?-, HO?, and hydrogen peroxide upon 4 MeV X-ray irradiation of their aqueous suspensions. Cytotoxic 1O2 is generated only in irradiation experiments containing the particles. Interestingly, X-ray irradiation of glioma C6 cells only produced reactive oxigen species (ROS) in cell cultures with incorporated particles. SiNPs capability of producing 1O2 upon X-ray irradiation opens novel approaches in the design of cancer therapy strategies.If SiNPs could be preferentially delivered to tumor sites, then the dose and the damage to healthy tissues could be reduced while preserving or enhancing the destructive effects for cancer. Surface properties? modifications as coating/linking with folate, antibodies, adjuvants, non-toxic poly(ethylene glycol), etc, may increase particles solubility, biocompatibility, targeting potential and circulation time, useful in the crossing of biophysical barriers and preventing opsonization. Combination of SiNPs with magnetic nanomaterials may allow the combination of fluorescence and magnetic resonance imaging. An approach to design bimodal imaging agents of low toxicity consists on iron-doped silicon nanoparticles (Fe-SiNPs).Thus, through intelligent design it is possible to develop multifunctional nanoparticles with potential applications in imaging and cancer therapy; however, care should be taken that their photo- and radiosensitising properties are preserved.On the other hand, the temperature dependence of the photoluminescence of SiNPs is an intrinsic property of the particles strongly depending on size and solvent media. These properties may be of importance for the use of the particles as temperature sensors based on photoluminescence measurements.The conference will focus on the particular properties of SiNPs which provide novel uses as photoluminiscent sensors in biological and technical systems. Among the properties to discuss are the particles photoluminiscence response to changes in the surrounding media, interaction with proteins, interaction with noble metal nanoparticles, and changes in temperature.