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SUMMARY:Biogenic Silver Nanoparticles for Visible-Light Activated Breast C
 ancer Photodynamic Therapy
DTSTART;VALUE=DATE-TIME:20260325T112000Z
DTEND;VALUE=DATE-TIME:20260325T114000Z
DTSTAMP;VALUE=DATE-TIME:20260426T163503Z
UID:indico-contribution-10317@events.saip.org.za
DESCRIPTION:Speakers: Isaac Baidoo (University of Johannesburg)\nSilver na
 noparticles (AgNPs) offer potent oncological potential via tunable SPR\, y
 et conventional toxicity remains a challenge. This study evaluates biogeni
 c synthesis and photoactivation as safer\, targeted alternatives for MCF-7
  and MDA-MB-231 breast cancer cells. Specifically\, plant-mediated (biogen
 ic) and chemically synthesized AgNPs were evaluated as wavelength-activate
 d nanotherapeutics under matched surface plasmon resonance excitation cond
 itions. Biogenic AgNPs exhibited an SPR maximum at ~466 nm\, whereas chemi
 cally synthesized AgNPs displayed a peak at ~401 nm. Upon irradiation at 4
 70 nm (biogenic) and 405 nm (chemical) with a fluence of 5 J/cm²\, distin
 ct photophysical and biological responses were observed.\nChemically synth
 esized AgNPs demonstrated modest photothermal conversion (ΔT ≈ 2.8 °C)
 \, while biogenic AgNPs showed negligible thermal elevation (<1 °C)\, ind
 icating minimal reliance on hyperthermic mechanisms. However\, biogenic Ag
 NPs generated substantially higher photoinduced reactive oxygen species (R
 OS)\, producing approximately threefold greater total ROS relative to chem
 ically synthesized counterparts under matched irradiation conditions. This
  enhanced photo-oxidative activity translated into significant reductions 
 in cell viability. In MCF-7 cells\, photoactivation of biogenic AgNPs redu
 ced the IC50 to <2 µg/mL\, compared with 2.89 ± 0.20 µg/mL under dark c
 onditions. In MDA-MB-231 cells\, irradiation lowered the IC50 from 11.26 
 ± 0.04 µg/mL (dark) to 4.79 ± 0.05 µg/ml. Flow cytometric analysis con
 firmed apoptosis as the predominant mechanism of cell death\, with late ap
 optotic populations approaching ~40% following photoactivation.\nThese res
 ults indicate that biogenic AgNPs induce ROS-mediated phototoxicity at low
 er doses\, achieving effective cytotoxicity under visible-light activation
  without significant thermal effects\, supporting their translational pote
 ntial in cancer treatment.\n\nhttps://events.saip.org.za/event/272/contrib
 utions/10317/
LOCATION:
URL:https://events.saip.org.za/event/272/contributions/10317/
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