Abstract 6236: Mil protein-shelled gold nanoparticle to treat glioblastoma multiform

Gold nanoparticle (AuNP) as a photothermal therapy (PTT) agent has been reported in various application due to its physical properties. If gold nanoparticle can be orally absorbed, its application may be extended. Unfortunately, it has low absorption efficiency from the gastrointestinal (GI) tract to blood stream. To overcome its limitation orally, here we newly synthesized lactoferrin (Lf; a milk protein)-conjugated gold nanoparticles (Lf-AuNP). Interestingly, this Lf-AuNP could be orally absorbed and targeted to the brain cancer cells due to its interaction with lactoferrin receptor (Lf-R) on the intestinal cells, Blood-Brain Barrier (BBB) and cancer cells. Based on these findings, the Lf-AuNP was orally absorbed with higher bioavailability and targeted to the brain cancer cells (U87MG cells) that was orthotopic animal model. Fortunately, when specified wavelength of laser was noninvasively irradiated to the head of orthotopic animals, the Lf-AuNP made the higher temperature to the head, thereby killing the brain cancer cells. Collectively this milk protein-based oral delivery of AuNP could be a promising strategy as a platform technology.

Citation Format: Hyungshik Kim, In-Kyu Park, Kang-Moo Huh, Dong-Yun Lee. Mil protein-shelled gold nanoparticle to treat glioblastoma multiform [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6236.

Micropatterning of poly(vinyl pyrrolidone)/silver nanoparticle thin films by ion irradiation

This study describes a new patterning method of poly(vinyl pyrrolidone) (PVP) containing silver nanoparticles by using ion irradiation. The thin films prepared from PVP/silver nanoparticle solutions were irradiated through a mask with accelerated H+ ions. Well-defined 50 microm line (pitch 150 microm) patterns were generated from the film irradiated at 1 x 10(16) ions/cm2. The heat treatment effect on the morphology of the patterns was investigated by using a scanning electron microscope with an energy dispersive X-ray spectrometer. The results confirmed that the silver nanoparticles were successfully immobilized in the PVP patterns and the patterns were changed into silver particles by heat treatment above 300 degrees C.

Modulatory factors on temperature-synchronized degradation of dextran grafted with thermoresponsive polymers and their hydrogels

Several types of dextran grafted with poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide [dextran-g-poly(NIPAAm-co-DMAAm)] with different graft lengths and numbers were synthesized in a preciously controlled fashion, and their enzymatic degradation was examined by viscosity measurement and gel permeation chromatography as a function of temperature. Degradation of dextran-g-poly(NIPAAm-co-DMAAm)s decreased with increasing the graft length below their lower critical solution temperatures (LCSTs). Above the LCST, enzymatic degradation was independent of the graft length. A larger amount of the graft chain with increasing the graft length rather than the graft number was effective to modulate the temperature-synchronized degradation. Hydrogels were prepared by cross-linking the graft copolymers using 1,6-hexamethylenediamine. While all the hydrogels have water content of about 93-96% in a wide range of temperatures, their degradation behaviors show a significant dependence on a temperature change. Such a unique property is closely related to the structure of graft copolymers such as graft lengths. Consequently, introducing thermoresponsive grafts with longer length to dextran and its hydrogels is suggested to be an important factor for modulating enzymatic degradation of dextran in synchronization with temperature.

Biodegradable amphiphilic multiblock copolymers and their implications for biomedical applications

Alternating multiblock copolymers composed of short blocks of poly(ethylene oxide) (PEO) and poly(epsilon-caprolactone) (PCL) or poly(L-lactic acid) (PLLA) were synthesized by a coupling reaction. The block copolymers of relatively high molecular weights (M(n)20,000) formed a physically crosslinked thermoplastic network, while low molecular weight polymers were water-soluble. The block copolymers demonstrated solubility in a variety of solvents including acetone, tetrahydrofuran, methylene chloride, dioxane, water/acetone mixtures, and water/ethanol mixtures. The degree of swelling, optical transparency, and mechanical property of the films, prepared by a solvent casting method, were affected by the nature of the hydrophobic block used, polymer composition, temperature, and thermal history. The crystalline melting temperatures of PCL and PLLA in the block copolymers were significantly lowered due to the chemical structure of difunctional PCL and PLLA, and partial phase mixing with PEO segments. The properties of the block copolymers may be useful for biomedical applications as well as controlled drug release formulations. When PEO/PLLA multiblock copolymers were applied as a wound healing material loaded with basic fibroblast growth factor (bFGF), the feasibility study showed improved wound healing when compared to controls of no treatment and the same wound covering without bFGF, indicating that a certain degree of the bioactivity of bFGF is preserved.