Polymer Thin Film-Induced Tumor Spheroids Acquire Cancer Stem Cell-like Properties.

: Although cancer stem cells (CSC) are thought to be responsible for tumor recurrence and resistance to chemotherapy, CSC-related research and drug development have been hampered by the limited supply of diverse, patient-derived CSC. Here, we present a functional polymer thin film (PTF) platform that promotes conversion of cancer cells to highly tumorigenic three-dimensional (3D) spheroids without the use of biochemical or genetic manipulations. Culturing various human cancer cells on the specific PTF, poly(2,4,6,8-tetravinyl-2,4,6,8-tetramethyl cyclotetrasiloxane) (pV4D4), gave rise to numerous multicellular tumor spheroids within 24 hours with high efficiency and reproducibility. Cancer cells in the resulting spheroids showed a significant increase in the expression of CSC-associated genes and acquired increased drug resistance compared with two-dimensional monolayer-cultured controls. These spheroids also exhibited enhanced xenograft tumor-forming ability and metastatic capacity in nude mice. By enabling the generation of tumorigenic spheroids from diverse cancer cells, the surface platform described here harbors the potential to contribute to CSC-related basic research and drug development. SIGNIFICANCE: A new cell culture technology enables highly tumorigenic 3D spheroids to be easily generated from various cancer cell sources in the common laboratory.

Characterization and application of porous gold nanoparticles as 2-photon luminescence imaging agents: 20-fold brighter than gold nanorods.

Two-photon nonlinear microscopy with the aid of plasmonic contrast agents is an attractive bioimaging technique capable of generating high-resolution images in 3 dimensions and facilitating targeted imaging with deep tissue penetration. In this work, physically synthesized gold nanoparticles containing multiple nanopores are used as 2-photon contrast agents and are reported to emit a 20-fold brighter 2-photon luminescence as compared to typical contrast agents, that is, gold nanorods. A successful application of our porous gold nanoparticles is experimentally demonstrated by in vitro nonlinear optical imaging of adipocytes at subcellular level.

Fabrication and characterization of plasma-polymerized poly(ethylene glycol) film with superior biocompatibility.

A newly fabricated plasma-polymerized poly(ethylene glycol) (PP-PEG) film shows extremely low toxicity, low fouling, good durability, and chemical similarity to typical PEG polymers, enabling live cell patterning as well as various bioapplications using bioincompatible materials. The PP-PEG film can be overlaid on any materials via the capacitively coupled plasma chemical vapor deposition (CCP-CVD) method using nontoxic PEG200 as a precursor. The biocompatibility of the PP-PEG-coated surface is confirmed by whole blood flow experiments where no thrombi and less serum protein adsorption are observed when compared with bare glass, polyethylene (PE), and polyethylene terephthalate (PET) surfaces. Furthermore, unlike bare PE films, less fibrosis and inflammation are observed when the PP-PEG-coated PE film is implanted into subcutaneous pockets of mice groin areas. The cell-repellent property of PP-PEG is also verified via patterning of mammalian cells, such as fibroblasts and hippocampal neurons. These results show that our PP-PEG film, generated by the CCP-CVD method, is a biocompatible material that can be considered for broad applications in biomedical and functional materials fields.