Flexible ZnO-mAb nanoplatforms for selective peripheral blood mononuclear cell immobilization

K Sowri Babu,Cátia F Marques,Suzana M Andrade,Pedro F Pinheiro,Gonçalo C Justino,Marta M Alves

doi:10.1038/s41598-020-72133-0

Abstract

Cancer is the second cause of death worldwide. This devastating disease requires specific, fast, and affordable solutions to mitigate and reverse this trend. A step towards cancer-fighting lies in the isolation of natural killer (NK) cells, a set of innate immune cells, that can either be used as biomarkers of tumorigenesis or, after autologous transplantation, to fight aggressive metastatic cells. In order to specifically isolate NK cells (which express the surface NKp30 receptor) from peripheral blood mononuclear cells, a ZnO immunoaffinity-based platform was developed by electrodeposition of the metal oxide on a flexible indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrate. The resulting crystalline and well-aligned ZnO nanorods (NRs) proved their efficiency in immobilizing monoclonal anti-human NKp30 antibodies (mAb), obviating the need for additional procedures for mAb immobilization. The presence of NK cells on the peripheral blood mononuclear cell (PBMCs) fraction was evaluated by the response to their natural ligand (B7-H6) using an acridine orange (AO)-based assay. The successful selection of NK cells from PBMCs by our nanoplatform was assessed by the photoluminescent properties of AO. This easy and straightforward ZnO-mAb nanoplatform paves the way for the design of biosensors for clinic diagnosis, and, due to its inherent biocompatibility, for the initial selection of NK cells for autotransplantation immunotherapies.

Highlights

Cancer is the second cause of death worldwide
The structure of zinc oxide (ZnO) NRs was confirmed by scanning electron microscopy (SEM), where well-organized ZnO NRs, with a hexagonal top surface, are homogeneously distributed on the flexible Indium Tin Oxide/PolyEthylene Terephthalate (ITO/polyethylene terephthalate (PET)) substrate (Fig. 1a–c)
The use of electrodeposition on a flexible indium tin oxide (ITO)/PET substrate resulted in the deposition of well-ordered ZnO NRs, adequate for monoclonal anti-human NKp30 antibodies (mAb) immobilization and natural killer (NK) cell selection

Summary

Introduction

Cancer is the second cause of death worldwide. This devastating disease requires specific, fast, and affordable solutions to mitigate and reverse this trend. In order to isolate NK cells (which express the surface NKp30 receptor) from peripheral blood mononuclear cells, a ZnO immunoaffinity-based platform was developed by electrodeposition of the metal oxide on a flexible indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrate. The successful selection of NK cells from PBMCs by our nanoplatform was assessed by the photoluminescent properties of AO. The use of immunoaffinity-based nanoplatforms, using monoclonal antibodies (mAb), to bind and select mammalian cells, while still relatively u nexplored[15], has a large potential for use in biomarker detection or as a tool for specific cell. ZnO NRs platforms can be used for the selection of peripheral blood mononuclear cells (PBMC) subtypes, in particular of Natural Killer (NK) cells, which are part of the host innate immune cells. The auto-transplantation of ex vivocultivated NK cells has led to an improved outcome in various cancer s ituations[17,18,19,20]

Methods

Results

Conclusion