Espenshade, Connor2023-05-232023-05-232021-09-162021-09-16https://repository.upenn.edu/handle/20.500.14332/45892Senescence, from the shortening of telomeres, accumulation of mutations, epigenetic hypomethylation, and other causes, begins an eventual cycle of decline in every patient. Stem cells disappear as a function of age, which in turn impairs cellular replication. Moreover, when fully differentiated cells are induced back into induced pluripotent stem cells (iPSCs), they not only revert to a state of pre-differentiation, but also to a younger cellular age. Their aging clocks turn back: their telomeres become longer and DNA methylation reverts back to an earlier age. It should therefore be possible to use iPSCs to replace the missing stem cells from aged organs and tissues and to replace existing, older tissue with younger cells. In order to accomplish this, this paper will also explore new nanotechnological mechanisms in generating patient-specific scaffolds, including two-photon polymerization, a fabrication process that uses a specifically focused, near-infrared laser to build three-dimensional scaffolds. This paper finally proposes a mechanism to apply iPSCs as preventative medicine, to replace aging organs before they fail and unwind the aging clock to lengthen healthspan.senescenceinduced pluripotent stem celltwo-photon polymerizationagingnanotechnologyscaffoldstissue engineeringtelomerestransplantBiochemistryBiochemistry, Biophysics, and Structural BiologyBioelectrical and NeuroengineeringBiological EngineeringBiologyBiology and Biomimetic MaterialsBiomaterialsBiomechanics and BiotransportBiomedicalBiomedical Devices and InstrumentationBiomedical Engineering and BioengineeringBiophysicsBiotechnologyElectrical and Computer EngineeringElectronic Devices and Semiconductor ManufacturingEngineering EducationEngineering Science and MaterialsHealth and Physical EducationIntegrative BiologyMaterials Science and EngineeringMolecular, Cellular, and Tissue EngineeringNanoscience and NanotechnologyNanotechnology FabricationOther Biochemistry, Biophysics, and Structural BiologyOther Biomedical Engineering and BioengineeringStructural BiologySystems and Integrative EngineeringReview