PolyScitech (
www.polyscitech.com)
provides a wide array of functionalized PLA/PLGA-PEG block copolymers with –COOH,
Maleimide, -NHS, bromoacetamide, and other PEG terminus functionality for
conjugation to targeting ligands and aptamers. Recently these types of polymers
were conjugated to tumor-specific aptamer TLS11a and utilized in nanoparticle
form to deliver doxorubicin to liver cancer cells. Read more: Shannon E. Weigum ; Melissa Sutton
; Eugenia Barnes ; Sarah Miller and Tania Betancourt "Targeting
hepatocellular carcinoma with aptamer-functionalized PLGA/PLA-PEG nanoparticles",
Proc. SPIE 9166, Biosensing and Nanomedicine VII, 916605 (August 27, 2014);
doi:10.1117/12.2062283; http://dx.doi.org/10.1117/12.2062283
“abstract: Hepatocellular carcinoma (HCC) is one
of the leading causes of cancer-related death worldwide, particularly in
regions where chronic Hepatitis B and C infections are common. Nanoparticle
assemblies that incorporate high-affinity aptamers which specifically bind
malignant hepatocellular carcinoma cells could be useful for targeted drug
delivery or enhancing contrast with existing ablation therapies. The in vitro
interactions of a tumor-specific aptamer, TLS11a, were characterized in a
hepatoma cell line via live-cell fluorescence imaging, SDS-PAGE and Western
Blotting techniques. Cell surface binding of the aptamer-AlexaFluor®546
conjugate was found to occur within 20 minutes of initial exposure, followed by
internalization and localization to late endosomes or lysosomes using a
pH-sensitive LysoSensor™ Green dye and confocal microscopy.
Aptamer-functionalized polymer nanoparticles containing poly(lactic-co-glycolic
acid) (PLGA) and poly(lactide)-b-poly(ethylene glycol) (PLA-PEG) were then
prepared by nanoprecipitation and passively loaded with the chemotherapeutic
agent, doxorubicin, yielding spherical nanoparticles approximately 50 nm in
diameter. Targeted drug delivery and cytotoxicity was assessed using live/dead
fluorescent dyes and a MTT colorimetric viability assay with elevated levels of
cell death found in cultures treated with either the aptamer-coated and
uncoated polymer nanoparticles. Identification and characterization of the cell
surface protein epitope(s) recognized by the TLS11a aptamer are ongoing along
with nanoparticle optimization, but these preliminary studies support continued
investigation of this aptamer and functionalized nanoparticle conjugates for
targeted labeling and drug delivery within malignant hepatocellular carcinomas.
Topics: Liver cancer ; Nanoparticles ; Polymers ; Cell death ; Proteins ;
Luminescence ; Cancer ; Colorimetry ; Confocal microscopy”
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