Binary colloidal crystals (BCCs) as a feeder-free system to generate human induced pluripotent stem cells (hiPSCs)

Abstract

Human induced pluripotent stem cells (hiPSCs) are capable of differentiating into any cell type and provide significant advances to cell therapy and regenerative medicine. However, the current protocol for hiPSC generation is relatively inefficient and often results in many partially reprogrammed colonies, which increases the cost and reduces the applicability of hiPSCs. Biophysical stimulation, in particular from tuning cell-surface interactions, can trigger specific cellular responses that could in turn promote the reprogramming process. In this study, human fibroblasts were reprogrammed into hiPSCs using a feeder-free system and episomal vectors using novel substrates based on binary colloidal crystals (BCCs). BCCs are made from two different spherical particle materials (Si and PMMA) ranging in size from nanometers to micrometers that self-assemble into hexagonal close-packed arrays. Our results show that the BCCs, particularly those made from a crystal of 2 μm Si and 0.11 μm PMMA particles (2SiPM) facilitate the reprogramming process and increase the proportion of fully reprogrammed hiPSC colonies, even without a vitronectin coating. Subsequent isolation of clonal hiPSC lines demonstrates that they express pluripotent markers (OCT4 and TRA-1-60). This proof-of-concept study demonstrates that cell reprogramming can be improved on substrates where surface properties are tailored to the application.

Controlled Attachment of Pseudomonas aeruginosa with Binary Colloidal Crystal‐Based Topographies

“…The evaporation‐induced confined area assembly process was used to make binary colloidal crystals on either hydrophilic glass or polystyrene substrates allowing production of BCC layers consisting of spherical larger Si particles interdispersed with smaller PMMA particles as described in detail earlier . In this study, three types of BCCs were assembled: 4.9 µm Si/0.4 µm PMMA (Si5/PMMA0.4), 3.7 µm Si/0.4 µm PMMA (Si3.7PMMA0.4), and 1 µm Si/0.1 µm PMMA (Si1/PMMA0.1).…”

Ex Vivo Expansion and Drug Sensitivity Profiling of Circulating Tumor Cells from Patients with Small Cell Lung Cancer

“…In this study, we developed an effective and reproducible ex vivo system for CTC expansion from SCLC patients. By implementing a biomimetic material called binary colloidal crystal (BCC) monolayers, building a complex topographic surface structure that displayed the capacity for expanding embryonic stem cells (ESCs) and inducing pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs) [ 24 , 25 , 26 , 27 , 28 ]. With the use of BCC as a bio-mimetic system, an optimized surface can be established to avoid harsh damages to these rare and fragile CTCs and aid the expansion of CTCs ex vivo.…”

“…Cells were seeded onto a substrate called binary colloidal crystals (BCCs). One BCC composed of Si and PMMA particles was selected from our BCC library in this study [ 25 ]. The medium was replaced in each well every four days.…”

Episomal Induced Pluripotent Stem Cells: Functional and Potential Therapeutic Applications

“…The human cells reported to have been successfully reprogrammed into EiPSCs include fibroblasts, epithelial cells, keratinocytes, mononuclear cells from adult peripheral blood, cord blood cells, amniotic fluid stem cells, mesenchymal stromal cells, lymphoblasts, lamina propria progenitor cells from oral mucosa, and urothelial cells obtained from urine. A summary of these reported human EiPSC sources is shown in Table 1 8,20,21,32 –43,47 –52,55,56,58,60 …”