Abstract
Isolating tumor exosomes (TEX) secreted by cancer cells can provide valuable information about the state of a tumor. Here, we present a method to rapidly isolate TEX using magnetic nanowires (MNWs). Specifically, two sets of Fe/Au segmented MNWs were used to isolate TEX released by canine osteosarcoma cell lines (OSCA 8, 32, and 40). These MNWs were prepared by electrodeposition showcasing similar length (2.2(1) μm) and diameter (36(3) nm) but different Fe/Au segment thickness: 120(20)/30(6) nm (sample A) and 28(7)/3(1) nm (sample B). Magnetic measurements indicate that we can effectively tune the magnetic response of the MNWs by changing their segment thickness, obtaining a more anisotropic behavior for sample A. The internalization of these MNWs by OSCA cells as a function of their concentration has been followed by fluorescence microscopy, and a concentration around 25 μg of Fe/Au MNWs per 3 × 105 cells has been defined as optimal. Electron microscopy images have revealed that, once internalized, these MNWs end up residing within lysosomes inside the cancer cells, where they tend to be degraded (especially the Fe segments) and fragmented into smaller pieces. Lower degradation for sample B has been observed and related to differences in the synthesis/functionalization process of both samples. We have hypothesized that these fragments of Fe/Au MNWs are packaged into TEX released to the medium which can then be isolated via a magnetic stand. This has been tested by carrying out TEX isolation experiments on the OSCA cell and comparing the magnetically isolated TEX with those isolated by using conventional methods based on centrifugation. Nanoparticle tracking analysis (NanoSight) has confirmed that the TEX isolated with MNWs have a comparable size distribution and yield to those obtained by using conventional methods, indicating that our magnetic isolation method can consistently provide relatively high TEX yields in a low-cost and fast way.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2058-2069 |
| Number of pages | 12 |
| Journal | ACS Applied Nano Materials |
| Volume | 3 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 28 2020 |
Bibliographical note
Funding Information:This work was supported by the MN Futures Program of the University of Minnesota, by the Skippy Frank Fund for Life Sciences and Translational Research, by Morris Animal Foundation Grant D15CA-047, and by the Animal Cancer Care and Research Program of the University of Minnesota. J.A. thanks the Nanobioap Cluster of Excellence and the Spanish Government for funding under Project MAT2017-83631-C3. K.M. acknowledges support from NIH Cancer Biology Training Grant T32 CA009138. A.D. was supported in part by postdoctoral training grant D16CA-405 from Morris Animal Foundation. Portions of this work were conducted in the Minnesota Nano Center, which is supported by the National Science Foundation through the National Nano Coordinated Infrastructure Network (NNCI) under Award ECCS-1542202. Parts of this work were carried out in the Characterization Facility, University of Minnesota, which receives partial support from NSF through MRSEC program. Z.N. thanks Guillermo Marques and Adrienne Sherman at the University Imaging Center (UMN), James Marti at the Minnesota Nano Center (UMN), and Jason C. Myers at the UMN Characterization Facility for their help and advice. Z.N. thanks Dr. Jaime Modiano for his continuous support and guidance.
Publisher Copyright:
© 2020 American Chemical Society.
Keywords
- cancer
- cell internalization
- exosomes
- magnetic isolation
- magnetic nanowires
