A major challenge in developing robust manufacturing processes for therapeutic cell products (TCPs) is being assured that the cells produced have the desired therapeutic potency. Many of the current separation and enrichment processes are based on sorting technologies using "affinity tags," which are adsorbents that bind cells specifically by targeting their surface markers. The process of removing these tags after sorting is completed is often associated with low yield and cell damage. The research goal of this project is to develop an innovative "affinity tag" based purification technology for separating complex mixtures of cells into cell fractions with different bioactivity and unique therapeutic value using light at controlled intensity and exposure time to control the binding and sequential release of different cell populations. The use of the "affinity tags" ensures that the recovered cells are highly pure, while the use of light as a biologically gentle mean to control cell binding ensures that the recovered cells are bioactive. The cell products targeted include stem and progenitor blood cells, which give rise to all the other blood cells, and can be administered by intravenous infusion into patients whose bone marrow or immune system is damaged or defective. The proposed technology is flexible, and can be easily adapted towards both research and processing scenarios, from use in basic cell biology and tissue engineering research, all the way to the production of clinically relevant amounts of cells. The interdisciplinary team encompassing the departments of Chemical Engineering, Biomedical Engineering, and the Biomanufacturing Training and Education Center (BTEC) at North Carolina State University will integrate research with a plan for workforce development and engagement with biotech companies. Activities include BTEC training opportunities for students and industrial and federal (FDA and BARDA) employees on cGMP processing of protein and cell therapeutics, incorporation of outcomes into existing BTEC courses on bioseparations, and creation of ad hoc half-semester and short courses targeted to biotech professionals on fractionation and purification of cell-based products. The project also plans to connect with stakeholders of NIIMBL, a NIST institute designed to innovate biomanufacturing in the United States, to develop joint research projects aimed at the large-scale translation of the project's cell distillery for TCP production.
The project proposes to develop a technology based on light-controlled affinity to separate stem cell populations into highly pure and bioactive fractions with distinct therapeutic value. This "cell distillery" employs marker-specific peptide ligands with light-controlled binding activity integrated in a microfluidic platform, to control cell binding and release based on the expression and density of cell surface markers. The ligands are designed to target cell markers selectively, and switch reversibly between ON and OFF binding modes upon exposure to visible/near IR light at specific wavelengths. The optimization of ligand density on the devices and light dosage ensures the recovery of highly pure and viable cell fractions. The project will demonstrate the technology by (1) separating hematopoietic stem cells (HSCs) from multipotent hematopoietic progenitor cells (HPCs), followed by the fractionation of (2) HSCs into long-term and short-term HSCs, and (3) HPCs into multipotent and lineage-committed HPCs. To this end, the project will develop light-responsive ligands for VCAM-1, CD38, and Flt-3 markers (Objective 1); correlate cell binding to ligand density and light irradiance (Objective 2); construct and characterize a microfluidic "cell distillery" for fractionating HSCs and HPCs obtained from commercial whole bone marrow aspirate or cord blood mononuclear cell fractions (Objective 3). The outcomes of this research have the potential to transform the science and technology of manipulation and isolation of therapeutic cell products (TCPs), opening new avenues in regenerative medicine and treatment of challenging malignancies.
