Integrating Biocatalysts into Metal-Organic Frameworks: Disentangling the Roles of Affinity, Molecular Weight, and Size.

The integration of biocatalysts within metal-organic frameworks (MOFs) is attracting growing interest due to its potential to both enhance biocatalyst stability and sustain biocatalyst activity in organic solvents. However, the factors that facilitate the post-synthetic infiltration of such large molecules into MOF pores remain unclear. This systematic study enabled the identification of the influence of biocatalyst molecular size, molecular weight and affinity on the uptake by an archetypal MOF, NU-1000. We analyzed a range of six biocatalysts with molecular weights from 1.9 kDa to 44.4 kDa, respectively. By employing a combination of fluorescence tagging and 3D-STED confocal laser scanning microscopy, we distinguished between biocatalysts that were internalized within the MOF pores and those sterically excluded. The catalytic functions of the biocatalysts hosted within the MOF were investigated and found to show strong variations relative to the solvated case, ranging from a two-fold increase to a strong decrease.

A Versatile Microfluidic Platform for Extravasation Studies Based on DNA Origami-Cell Interactions.

The adhesion of circulating tumor cells (CTCs) to the endothelial lumen and their extravasation to surrounding tissues are crucial in the seeding of metastases and remain the most complex events of the metastatic cascade to study. Integrins expressed on CTCs are major regulators of the extravasation process. This knowledge is primarily derived from animal models and biomimetic systems based on artificial endothelial layers, but these methods have ethical or technical limitations. We present a versatile microfluidic device to study cancer cell extravasation that mimics the endothelial barrier by using a porous membrane functionalized with DNA origami nanostructures (DONs) that display nanoscale patterns of adhesion peptides to circulating cancer cells. The device simulates physiological flow conditions and allows direct visualization of cell transmigration through microchannel pores using 3D confocal imaging. Using this system, we studied integrin-specific adhesion in the absence of other adhesive events. Specifically, we show that the transmigration ability of the metastatic cancer cell line MDA-MB-231 is influenced by the type, distance, and density of adhesion peptides present on the DONs. Furthermore, studies with mixed ligand systems indicate that integrins binding to RGD (arginine-glycine-aspartic acid) and IDS (isoleucine-aspartic acid-serine) did not synergistically enhance the extravasation process of MDA-MB-231 cells.

Synthesis, Characterization, and Biological Properties of Steroidal Ruthenium(II) and Iridium(III) Complexes Based on the Androst-16-en-3-ol Framework.

A range of novel cyclometalated ruthenium(II) and iridium(III) complexes with a steroidal backbone based on androsterone were synthesized and characterized by NMR spectroscopy and X-ray crystallography. Their cytotoxic properties in RT112 and RT112 cP (cisplatin-resistant) cell lines as well as in MCF7 and somatic fibroblasts were compared with those of the corresponding nonsteroidal complexes and the noncyclometalated pyridyl complexes as well as with cisplatin as reference. All steroidal complexes were more active in RT112 cP cells than cisplatin, whereby the cyclometalated pyridinylphenyl complexes based on 5c showed high cytotoxicity while maintaining low resistant factors of 0.33 and 0.50.

Cocktail of lipophilic and hydrophilic chemotherapeutics in high-load core@shell nanocarriers to treat pancreatic tumours.

ITC/Toc@Gd2(FLP)3 core@shell nanocarriers with a chemotherapeutic cocktail of lipophilic irinotecan (ITC) as the particle core and hydrophilic fludarabine phosphate (FLP) in the particle shell are realized. They are prepared via a microemulsion approach with ITC dissolved in tocopherol (Toc) as droplet phase and stabilized by water-insoluble Gd2(FLP)3. The synthesis can be followed by zeta-potential analysis. X-ray powder diffraction, infrared spectroscopy, elemental analysis, thermogravimetry, and photometry show a drug load of 49 µg per mL ITC and 317 µg per mL FLP at a nanocarrier concentration of 1.5 mg mL-1. Size and structure are evidenced by electron microscopy, resulting in a total diameter of 45 ± 16 nm, an inner core of 40 ± 17 nm, and a shell of 3-8 nm. In vitro studies with different cancer cell lines (i.e., human melanoma/SK-Mel-28, cervical cancer/HeLa, mouse pancreatic cancer/Panc02 and KPC as well as human pancreatic cancer/Capan-1 cells) prove efficient nanocarrier uptake and promising cytostatic efficacy. Specifically for KPC cells, ITC/Toc@Gd2(FLP)3 nanocarriers show an increased efficacy, with half maximal inhibitory concentration (IC50: 4.2 µM) > 10 times lower than the free drugs (IC50: ITC: 47.7 µM, FLP: 143 µM). This points to the synergistic effect of the ITC/FLP drug cocktail in the nanocarriers and may result in a promising strategy to treat pancreatic ductal adenocarcinoma (PDAC).

Theranostic inorganic-organic hybrid nanoparticles with a cocktail of chemotherapeutic and cytostatic drugs.

Theranostic inorganic-organic hybrid nanoparticles (IOH-NPs) with a cocktail of chemotherapeutic and cytostatic drugs and a composition Gd23+[(PMX)0.5(EMP)0.5]32-, [Gd(OH)]2+[(PMX)0.74(AlPCS4)0.13]2-, or [Gd(OH)]2+[(PMX)0.70(TPPS4)0.15]2- (PMX: pemetrexed, EMP: estramustine phosphate, AlPCS4: aluminum(III) chlorido phthalocyanine tetrasulfonate, TPPS4: tetraphenylporphine sulfonate) are presented for the first time. These IOH-NPs are prepared in water (40-60 nm in size) and have a non-complex composition with outstanding drug loading (71-82% of total nanoparticle mass) of at least two chemotherapeutic or a mixture of cytostatic and photosensitizing agents. All IOH-NPs show red to deep-red emission (650-800 nm) to enable optical imaging. The superior performance of the IOH-NPs with a chemotherapeutic/cytostatic cocktail is validated based on cell-viability assays and angiogenesis studies with human umbilical vein endothelial cells (HUVEC). The synergistic anti-cancer effect of the IOH-NPs with a chemotherapeutic cocktail is shown in a murine breast-cancer cell line (pH8N8) and a human pancreatic cancer cell line (AsPC1), whereas the synergistic cytotoxic and phototoxic efficacy is verified in response to illumination of HeLa-GFP cancer cells, MTT assays with human colon cancer cells (HCT116), and normal human dermal fibroblasts (NHDF). HepG2 spheroids as 3D cell cultures prove the effective uptake of the IOH-NPs with high uniform distribution and the release of the chemotherapeutic drugs with the strong synergistic effect of the cocktail of drugs.