COLO-818

Cell Viability Experiment on ^DOXPMOF, ^DOXPMOF-PDL, Free-PDL, and Free-DOX

Solid tumors often suffer from hypoxia, which promotes cancer cell aggressiveness and tissue damage. Therefore, a pH-responsive nanomaterial that co-delivers oxygen and anticancer drug was synthesized. The material offers 14 days of sustained oxygen release and 30 days of pH-dependent drug release under hypoxic conditions.

In a one-pot synthesis, Kehr et al. integrated oxygen-carrying PFC units into the PMO network (PMOF) due to PFC's oxygen-dissolving capacity. The PMOF pores were loaded with DOX for drug delivery and then coated with PDL to create pH-responsive ^DOXPMOF-PDL. To assess the impact on cell viability, they treated fibroblast and Colo 818 cells with ^DOXPMOF, ^DOXPMOF-PDL, free-PDL, and free-DOX. The cell viabilities were then quantified after 1 and 7 days (Fig. 1). The results showed that DOX and PDL alone reduced the cell viabilities of both normal and cancer cells. In most other cases, the immobilization of DOX and PDL on PMOF improved cell viabilities. Of note, ^DOXPMOF-PDL increased the healthy cell viability by 15%, 79%, and 95% compared to cell culture plate, free-PDL and free-DOX, respectively, and decreased the cancer cell viability by 50% compared to cell culture plate, and increased the viability by 25% and 73% compared to free-PDL and free-DOX after 7 days. In addition, healthy cells within ^DOXPMOF-PDL sample showed 59% higher viability than cancer cells after 7 days. In conclusion, immobilizing DOX and PDL on PMOF reduced the inhibitory effects of both molecules on the cell viability, especially in healthy cells due to higher DOX release in the acidic environment of cancer cells.

Cell Experiments in the GA5, GA10, and GA10-P Hydrogels

Existing biomaterials frequently lack multi-functionality and precise control of cellular behavior. Motealleh et al. presented a novel step-gradient composite hydrogel (GradGA) 3D bioprinted with a multifunctional NM, Alg and gelatin methacryloyl, with the aim of fabricating a biomaterial that can support healthy cell viability and migration, but not cancer cell growth, by utilizing pH-responsive drug release.

Cell experiments were performed to compare the effects of GelMA, Alg, and the composite (GA10) on cell viability, confirming the advantage of the addition of GelMA into Alg. GelMA, Alg, and GA10 were separately incubated with healthy dermal fibroblasts and malignant melanoma fibroblasts (Colo 818) for 1 and 7 days, after which cell viability was determined using PrestoBlue (Fig. 2). Data revealed higher cell viability in GA10 over GelMA or Alg, especially after 1 day. This suggested a synergistic effect of GelMA and Alg on cellular viability, leading to further experiments of GelMA/Alg-based composites with different ratios (GA5, GA10 and GA10-P).