Long-Time Behavior of Surface Properties of Microstructures Fabricated by Multiphoton Lithography

The multiphoton lithography (MPL) technique represents the future of 3D microprinting, enabling the production of complex microscale objects with high precision. Although the MPL fabrication parameters are widely evaluated and discussed, not much attention has been given to the microscopic properties of 3D objects with respect to their surface properties and time-dependent stability. These properties are of crucial importance when it comes to the safe and durable use of these structures in biomedical applications. In this work, we investigate the surface properties of the MPL-produced SZ2080 polymeric microstructures with regard to the physical aging processes during the post-production stage. The influence of aging on the polymeric microstructures was investigated by means of Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). As a result, a time-dependent change in Young’s Modulus, plastic deformation, and adhesion and their correlation to the development in chemical composition of the surface of MPL-microstructures are evaluated. The results presented here are valuable for the application of MPL-fabricated 3D objects in general, but especially in medical technology as they give detailed information of the physical and chemical time-dependent dynamic behavior of MPL-printed surfaces and thus their suitability and performance in biological systems.

Cohort Differences and Similarities in Women's Attitudes About Self and Aging

This panel focuses on four complementing and international views of women’s aging, with a special emphasis on cohort comparisons and using three different studies of women, with contrasting methodological frameworks. In so doing, we present evidence related to trends in social percepetions of aging, attitudes about aging and identity, and ideas about control and objectification. Dr. Newton presents data on older Canadian women showing the connection between physical aging and identity maintenance, using both qualitative and quantitative data and using the lifecourse perspective. Dr. Ryan, using data from the Health and Retirement Study to compare cohorts of women from the 2008 and 2018 HRS waves, reports cohort differences in negative self-perceptions of aging, and that both cohort and negative self-perfections are associated with life satisfaction, using the life course developmental framework. Ms. Tran compares younger and older cohorts of women on a measure of self-objectification, finding that the older cohort reported lower objectification, consistent with a selection, optimization, and compensation (SOC) model. Finally, Dr. Sherman, using the same data set as Ms. Tran, shows that control beliefs are associated with objectification, regardless of cohort, consistent with objectification theory predictions of consistency over time regarding the impact of objectification experiences. Dr. Jamila Bookwala will provide discussion of this group of papers.

Differentially Methylated Genes in Muscle Associated with Gait Speed in a Non-Human Primate Model of Aging

Age-related changes in DNA methylation are potent regulators of gene expression and may in part explain the onset of disease and disability. Vervet monkeys are a well-described model of neurocognitive and physical aging. Like humans, gait speed declines with age in vervets, and variability in gait speed in older animals is associated with age-related musculoskeletal and cognitive decline. To identify methylation patterns linked to aging-related physical decline, we investigated differentially methylated loci in vastus lateralis biopsies of 29 female vervets aged 8-28 years (~25-90 years in humans). We evaluated 107,490 loci on the Illumina Infinium Methylation EPIC Human Array that aligned with high fidelity to the vervet genome using the R package minfi and fit generalized linear mixed models to account for underlying genetic relatedness. We found 13 CpG methylation sites associated with 12 genes (CALCR, EBF4, GDNF, GMCL1, HAND1, HOXC10, IRX2, LBX2, MPPED2, SHISA6, SOX2, and WNT2) significantly differentially methylated with gait speed. Increased methylation was negatively associated with gait speed for all loci except GMCL1, reflecting the pattern of global hypermethylation of skeletal muscle tissue with age. Several of the associated genes are involved in development and differentiation including HOXC10 and LBX2, which regulates myoblast migration. CACNG8 regulates voltage-dependent calcium gated channels, and GDNF promotes motor neuron innervation of skeletal muscle. Most associations with muscle phenotypes are novel, but several have been linked to age-related bone diseases. We are currently evaluating the relationships of these differentially methylated loci with muscle mRNA expression and protein abundance.