Digitalized Human Organoid for Wireless Phenotyping

摘要

class="head no_bottom_margin" id="sec1title">IntroductionRadio frequency identification (RFID) is a cost-effective technology for addressing personal identification, traceability, and environmental considerations, especially in transportation industries, which has permeated all facets of modern life (, , ). RFID tags, operating wirelessly, collect energy from a nearby reader's interrogating radio waves. The high degree of tolerance to tested solutions, solvents, extreme temperatures, and high- or low-pressure conditions () provides the RFID tags with significant advantages over barcodes. The tags are now integrated into cards, clothing, and possessions, as well as implanted into animals and humans. For example, RFID tags are incorporated into cards and are used to pay for mass transit fares on buses, trains, and subways and to collect tolls on highways in many countries. In 2017, the world RFID market, which includes tags, readers, software/services for RFID cards, labels, fobs, and all other form factors, was worth US$11.2 billion and has an estimated 10% annual growth, resulting in an anticipated value of US$18.68 billion by 2026 ().In recent years, there has been considerable interest in extending the usage of RFID to the healthcare arena. For example, implanting RFID microchips in animals and humans allows for positive identification of specific individuals. Medical application of RFID now includes an oral “digital pill” for chronic conditions, in efforts to improve patients' adherence (, ). The ingested radiofrequency emitter, once activated by gastric pH, emits a radiofrequency signal, which is captured by a relay hub and transmitted to a smartphone, where it provides ingestion data and deliver interventions in real time. Thus, the diverse applications of RFID provide innovative solutions to various biomedical challenges. Similarly, RFID incorporation into cells or tissues can provide advancements in tracking in vitro and in vivo processes, in drug discovery, and in understanding disease mechanisms. Recent applications of micro RFID showed the passive intra-cellular delivery and short-term persistence; however, the use of mouse phagocytic cell line and melanoma cell line limit its broader application (). Thus, realistic RFID applications in the tissue culture context necessitates viable methods to incorporate the microchip into biological tissue without impairing the tissue's native structure and functions.Recently, human organoids have received international attention as an in vitro culture system where human stem cells self-organize into three-dimensional (3D) structures reminiscent of human organs (, , ). Organoids, owing to their higher phenotypic fidelity to human disease (), are expected to provide a mechanistic assay platform with future potential for drug screening and personalized medicine (, , ). It becomes feasible to study human pathological variations by comparing genotypes with phenotype spectrum diseases, including cystic fibrosis (href="#bib19" rid="bib19" class=" bibr popnode">Saini, 2016), steatohepatitis (Takanori Takebe et al., Unpublished), and cholestatic disease (Takanori Takebe et al., Unpublished), using a human induced pluripotent stem cell (iPSC) or adult stem cell library. One key feature of organoids is the development of a polarized structure surrounded by basement membrane through a self-assembly process, resulting in a cavitated structure from an aggregated tissue. Therefore, we hypothesized that aggregation-mediated self-assembling process will enable the successful internalization of miniature chips into biological tissues without compromising the native functions of the tissues.Herein, we test this hypothesis by integrating ultracompact RFID chips into re-aggregated iPSC-derived endoderm spheroids before self-assembly. Recent advancements in miniaturization have generated ultra-compact RFID microchips ranging in size from 10 to 600 μm (href="#bib2" rid="bib2" class=" bibr popnode">Burke and Rutherglen, 2010, href="#bib4" rid="bib4" class=" bibr popnode">Chai et al., 2016, href="#bib5" rid="bib5" class=" bibr popnode">Chen et al., 2013). For simplicity and accessibility, we used commercially available organoid-scale RFID chips, herein defined as the O-Chip. The concept of organoid digitalization with O-Chip is shown in href="/pmc/articles/PMC6147234/figure/fig1/" target="figure" class="fig-table-link figpopup" rid-figpopup="fig1" rid-ob="ob-fig1" co-legend-rid="lgnd_fig1">Figure 1A. Each O-Chip is 460 × 480 μm and has a 512 bit memory area (href="/pmc/articles/PMC6147234/figure/fig1/" target="figure" class="fig-table-link figpopup" rid-figpopup="fig1" rid-ob="ob-fig1" co-legend-rid="lgnd_fig1">Figure 1B). By applying a specific wavelength into a coiled antenna, each O-Chip receives data sent from the reader/writer, and with energy driven by this electric current the O-Chip wirelessly sends information stored in its memory. The O-Chip operates wirelessly from readers across distances of up to about 1–2 mm.href="/pmc/articles/PMC6147234/figure/fig1/" target="figure" rid-figpopup="fig1" rid-ob="ob-fig1">class="inline_block ts_canvas" href="/core/lw/2.0/html/tileshop_pmc/tileshop_pmc_inline.html?title=Click%20on%20image%20to%20zoom&p=PMC3&id=6147234_gr1.jpg" target="tileshopwindow">target="object" href="/pmc/articles/PMC6147234/figure/fig1/?report=objectonly">Open in a separate windowclass="figpopup" href="/pmc/articles/PMC6147234/figure/fig1/" target="figure" rid-figpopup="fig1" rid-ob="ob-fig1">Figure 1Concept of Organoid Digitalization with O-Chip(A) A schematic of organoid digitalization strategy. Integration of O-Chip into organoids makes it possible to digitalize organoids.(B) The size of the O-Chip: 0.46 ×0.48 μm².(C) Self-condensation culture with O-Chip (href="#bib21" rid="bib21" class=" bibr popnode">Takebe et al., 2015). Serial pictures show that O-Chips are being integrated into organoids formed from iPSC derivatives.(D) RiO morphology. Each organoid completely encompasses one RFID microchip. Scale bars for RiO, 200 μm; for zoomed-in images, 100 μm.