Deficient muscle-specific strength has been recognized as a key component of sarcopenia. However, the impact of various interventions on muscle-specific strength has not been systematically reviewed. This study aims to provide a systematic summary of research examining the effects of exercise, nutrition, and other interventions on muscle-specific strength in older adults. Randomized controlled trials (RCTs) were identified through comprehensive searches of major databases. Eligible studies included adults aged 60 years or older, with interventions lasting at least 8 weeks. Studies were required to assess muscle strength normalized by muscle mass. Standardized mean differences (SMDs) were calculated using random-effects meta-analyses, and heterogeneity was evaluated using I² statistics. A total of 41 RCTs with 3,141 participants were included in the analysis. Interventions included resistance exercise, nutritional supplementation, aerobic exercise, concurrent training, combined exercise and nutrition, caloric restriction, and other therapies. Resistance exercise significantly improved muscle-specific strength (SMD = 0.61, 95% confidence interval: 0.27 to 0.94), although heterogeneity was observed (I² = 81%). In contrast, interventions such as aerobic exercise, concurrent training, combined exercise and nutrition, and nutritional supplementation did not lead to significant improvements in muscle-specific strength. High heterogeneity was observed across all included studies. Resistance exercise is the most effective intervention for improving muscle-specific strength in older adults. The effects of other interventions, such as nutritional supplementation and aerobic exercise, remain inconclusive. Further well-designed RCTs exploring diverse exercise regimens and nutritional interventions are needed to confirm these findings and identify the most effective strategies for enhancing muscle-specific strength in older populations.
Physical activity (PA) and inactivity have opposing associations with skeletal muscle function and are often studied separately but are codependent. We evaluated cross-sectional associations between 24hr time-use behaviors with muscle strength and power. Sample included 751 community-dwelling older adults (76±5 years, 57% women). Compositional data analysis determined 24hr proportions of time in moderate-to-vigorous (MVPA) and light intensity PA (LPA), inactivity, and sleep. Multiple linear regression by sex evaluated associations between 24hr composition with stair climb ascend and leg press power (W), and leg press (lbs) and grip strength (kg). Compositional isotemporal substitution quantified hypothetical reallocations of time between behaviors on power and strength. Compared to the average 24hr-day in women (MVPA: 84 min/day, LPA: 349 min/day, inactivity: 559 min/day, sleep: 448 min/day), higher 24hr proportions of MVPA were associated with higher stair climb power (β: 16.2, 95%CI: 10.9, 21.4), leg press power (β: 23.7, 95%CI: 10.3, 37.2), and leg strength (β: 8.5, 95%CI: 2.4, 14.6); higher 24hr proportions of LPA were associated with lower stair climb power (β: -14.4, 95%CI: -25.8, -3.0); and higher 24hr proportions of inactivity were associated with higher grip strength (β: 2.3, 95%CI: 0.4, 4.3). Compositional isotemporal substation found reallocating 10 minutes from LPA or inactivity to MVPA support higher power and strength. No associations were observed in men. In women, not men, 24hr movement composition was associated with power and strength. MVPA interventions for power and strength improvements in women may be optimized when LPA or inactivity are reduced, not sleep.
The reproductive lifespan encompasses important transitions in women's health, including midlife and menopause, yet whole-person strengths, challenges, and unmet needs across this continuum remain poorly characterized. This study examined multidimensional self-reported health profiles across three age-based groups representing different stages of adult life. Retrospective comparative study using de-identified consumer-generated health data from the MyStrengths+MyHealth digital assessment, a validated whole-person tool grounded in the Omaha System. Data were collected from community-based settings in a Midwestern metropolitan area (2019-2023). Women were categorized by age as a proxy for reproductive stage: reproductive-aged (25-44, n = 253), midlife (45-64, n = 329), and later adulthood (65+, n = 124). Group differences in Strengths, Challenges, and Needs across four whole-person health domains were analyzed using descriptive and inferential statistics. Self-reported domain-level Strengths rating, Challenge counts, and Need counts across 37 health concepts. Later adulthood and midlife women reported significantly higher Strengths than reproductive-aged women (p < 0.001). Reproductive-aged women reported the greatest burden of Challenges (M = 44.9, SD = 32.0) and Needs (M = 33.6, SD = 22.7) distributed across the widest range of health concepts (all p < 0.001). Exercise was the most prevalent Challenge across all groups. Midlife women generated the highest total volume of Needs at the population level. Whole-person consumer-generated health data suggest that substantial challenges and unmet needs emerge well before midlife, underscoring the potential value of upstream, strengths-based, and personalized interventions to promote resilience and healthy aging across the reproductive lifespan. Additional longitudinal and population-based studies are needed to confirm these findings and evaluate their implications for clinical practice.
BackgroundLateral epicondylitis (LE) is a prevalent overuse injury among workers performing repetitive wrist movements. Altered wrist range of motion (ROM) and reduced muscle strength occur in individuals with LE; however, their combined utility for classifying LE remains unclear. Interpretable machine learning can help identify and explain biomechanical features associated with LE.ObjectiveThis study developed and interpreted machine learning models to classify LE among assembly line workers using wrist ROM and muscle strength data, identifying the most influential biomechanical predictors using SHapley Additive Explanations (SHAP).MethodsData from 45 male assembly line workers (23 with LE, 22 without LE) were used. Predictor variables included wrist ROM (flexion, extension, radial deviation, ulnar deviation) and muscle strength (flexors, extensors, grip strength). Predictors were standardized within each training fold, and Gaussian noise augmentation was applied to training data. Four machine learning models were tuned using grid search and evaluated via repeated stratified 5-fold cross-validation. Discrimination, classification performance, and calibration were assessed, and SHAP was used for model interpretation.ResultsAll four models achieved comparable discrimination (accuracy: 0.83-0.87; ROC-AUC: 0.91-0.92). Support vector machine showed the highest accuracy, whereas logistic regression showed the highest ROC-AUC. SHAP analysis consistently identified wrist radial deviation ROM as the most influential predictor across all models, with lower values linked to higher LE probability.ConclusionInterpretable machine learning models classified LE with good cross-validated discrimination using simple biomechanical measurements. Reduced radial deviation ROM was consistently the strongest predictor, suggesting its relevance in LE assessment in assembly line workers.
High-accuracy NIRS models and GWAS identified a novel QTL qPO-A07-1. GhMYB86 was validated to enhance seed protein content and fiber strength, and a functional KASP marker was developed. Cottonseed is rich in protein and oil; improving its nutritional quality is vital for global food security. In this study, near-infrared spectroscopy (NIRS) models were developed for predicting cottonseed protein and oil content using least absolute shrinkage and selection operator (LASSO) regression, achieving validation R2 of 0.969 (P < 0.01) and 0.972 (P < 0.01), respectively. Using these models, 249 upland cotton (Gossypium hirsutum L) accessions were phenotyped across five environments and subjected to a genome-wide association study (GWAS) based on a 10-K liquid-phase single-nucleotide polymorphism (SNP) array, resulting in the identification of 24 significant loci (P < 1 × 10-4). A novel stable quantitative trait locus (QTL), qPO-A07-1, was detected, within which GhMYB86 was prioritized as a candidate gene. This gene exhibited higher expression in high-protein-content varieties during ovule development. Heterologous overexpression in Arabidopsis thaliana increased seed protein content by 2.61-3.34%, whereas expression in Saccharomyces cerevisiae increased protein content by 25.81% and reduced triglyceride content by 30.72% in comparison with the control. These results demonstrate that GhMYB86 positively regulates protein content while negatively affecting oil content. A kompetitive allele-specific PCR (KASP) marker targeting a promoter A/T polymorphism revealed that the AA allele was associated with higher-protein content, lower-oil content, and increased fiber strength across both mapping and validation populations. Furthermore, the protein content- and fiber strength-favorable allele has undergone positive selection during breeding. This study provides phenotyping tools, reliable genetic resources and a molecular marker for cottonseed nutritional quality breeding, laying a foundation for the improvement in cottonseed protein content and fiber strength.
To evaluate the effect of different surface pretreatment protocols on the repair bond strength and integrity of resin composite to three different resin matrix ceramics (RMCs). Three RMCs - Cerasmart (CS), Grandio blocs (GB) and Katana Avencia (KA) - were subjected to one of three mechanical surface treatments: polishing, diamond bur roughening, or sandblasting. These were randomly assigned to four conditioning groups: 10-MDP and silane-containing adhesive (Clearfil Universal Bond Quick), 10-MDP-based adhesive (G-Premio Bond), 9% buffered hydrofluoric acid (HF) plus silane, and a 10-MDP and silane-free adhesive (Heliobond). A nanohybrid composite (Reflectys) was applied as the repair material. Specimens were sectioned into sticks and subjected to micro-tensile bond strength (µTBS) testing using a universal testing machine. The surface treatments were compared by one-way ANOVA and post-hoc tests for different cases of the variables µTBS and surface roughness. For CS, the combination of sandblasting and 10-MDP plus silane-containing adhesive yielded the highest µTBS (46.42 ± 3.12 MPa), with no significant difference observed between polishing and bur roughening. Similarly, GB showed significantly higher µTBS when sandblasted and treated with 10-MDP plus silane adhesive (42.01 ± 5.06 MPa). However, for KA, the most effective protocol was the combination of sandblasting and 9% buffered HF with silane (48.31 ± 8.46 MPa). Repair bond strength is highly dependent on the specific RMC used. No single universal mechanical surface treatment or conditioning protocol was found to be optimal across all materials. Clinicians should utilise individualised repair protocols - specifically 10-MDP and silane-containing adhesives for CS and GB, and HF and silane for KA - to achieve maximum repair bond strength. When repairing RMC restorations chairside, clinicians should identify the specific material brand, whenever possible, as the chemical composition of the RMC dictates whether a universal adhesive or a traditional HF and silane protocol will provide the most durable immediate repair.
The depletion of fossil fuels and environmental pollution caused by the accumulation of plastic packaging have led to a booming rise in the demand for eco-friendly packaging materials as alternatives. In this study, nanocellulose (NC) extracted from pineapple leaves using acid pretreatment and alkali treatment was incorporated into poly-(vinyl alcohol) (PVA) and pectin blends to enhance their functional properties. The extracted NC was characterized using different analytical techniques like scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The morphological, thermal, barrier, optical, mechanical, and antibacterial properties of the NC-incorporated films were evaluated. NC incorporation significantly enhanced the films, resulting in improvements in thermal stability, mechanical strength, UV shielding, and hydrophobicity of films. The tensile strength (TS) and elongation at break (EAB) of the films increased to 9.03 ± 0.88 and 515.33 ± 6.43 MPa at 0.3 and 0.4 wt % addition of NC, respectively, while the maximum thermal stability was observed at 0.3 wt % NC incorporation. The films also exhibited excellent UV shielding property in both UVA (70.03%) and UVB (88.59%) regions and enhanced hydrophobicity, with a 42.7% increase in water contact angle (WCA), a 15.6% reduction in water solubility (WS), and a 75.7% decrease in water vapor transmission rate (WVTR), indicating improved moisture barrier performance. The findings demonstrate the reinforcing effect of the pineapple leaf-derived nanocellulose in PVA/pectin films with the potential for application in fresh produce packaging.
Landfill leachate is a pathway for PFAS release from end-of-life waste systems, but its source strength, mixture evolution, and risks remain poorly quantified. We compiled 1416 samples from 539 facilities in 76 cities across 22 countries, covering 150 legacy and emerging PFAS. ΣPFAS ranged from 1 to 5542,000 ng/L, with 93%/56% of sites exceeding 1000/10,000 ng/L, indicating high source strength. High-burden samples clustered in hotspot regions and landfill types rather than by continent. Industrial landfills showed the strongest signature, averaging 1141,345 ng/L, 56-101 times higher than other landfill types, and contributing 62% of the global burden. FOSA, PFOA, and PFBA accounted for over half of cumulative PFAS, while country-level fingerprints diverged into long-chain, short-chain, and precursor-enriched patterns, recording legacy use, replacement inputs, and precursor transformation. Higher PFAS concentrations were associated with organic matter, salts, and ammonium, especially TOC and COD (P < 0.001). Regional PLS-SEM explained only 22.4% of variance, highlighting facility-scale waste composition, receiving history, and operation. Risk screening showed long-chain PFAS dominated toxicity-weighted pressure, with SSD-derived PFOS HC5 values of 2.58-25.99 ng/L, over one order of magnitude lower than PFOA. Short and ultrashort PFAS created another pressure through mobility, persistence, and treatment resistance. Overall, landfill leachate is a dynamic PFAS source term controlled by high-risk waste inputs, delayed release, precursor transformation, and geochemistry. Management should shift from end-of-pipe control to fluorinated-waste identification, precursor reduction, mobile short-chain control, and residual management.
Sex steroids play a key role in skeletal muscle regulation, yet sex-specific links between estradiol, testosterone-estrogen balance, and muscle health in midlife remain sparse. In this study we evaluated associations between circulating estradiol and testosterone-to-estradiol (T/E) ratio with handgrip strength (HGS) and appendicular lean soft tissue index (ALSTI) in men and women aged 40-59 years. We analyzed data from 1350 adults [48.8 (5.7) years, 693 women] participating in NHANES 2013-2014. HGS was assessed using a handheld dynamometer, and ALSTI by dual-energy X-ray absorptiometry. Sex-specific linear and logistic regression models examined associations of estradiol and T/E with continuous and categorical muscle outcomes. Complementary analyses examined log10-transformed estradiol, T/E ratio, and total testosterone, with SHBG included in sensitivity analyses. In unadjusted analyses, higher estradiol was associated with greater ALSTI in men (b = 0.43, 95% CI 0.25 to 0.61) and higher HGS in women (b = 1.56, 95% CI 0.92 to 2.20), while higher T/E was associated with lower HGS and ALSTI in men (b = -1.87, 95% CI -3.19 to -0.55, and b = -0.74, 95% CI -1.02 to -0.46, respectively) and lower HGS in women (b = -1.84, 95% CI -2.69 to -0.99). However, these associations were largely attenuated after multivariable adjustment. In logistic models, women with lower estradiol concentrations had significantly higher odds of low HGS compared with those with higher estradiol in Model 2 (OR = 2.44, 95% CI 1.01 to 5.88), while the association with moderate estradiol levels did not reach statistical significance (OR = 2.27, 95% CI 0.98 to 5.26). These associations were attenuated after additional adjustment for SHBG. No corresponding associations were observed in men. The T/E ratio was not independently associated with low HGS after adjustment in either sex. Circulating estradiol and T/E show sex-specific associations with muscle health. Lower estradiol was associated with higher odds of low HGS in women in the primary adjusted analysis, whereas most other hormone-muscle associations were attenuated after adjustment. These findings support further longitudinal studies to clarify sex-specific hormone-muscle trajectories across midlife.
Driven by the needs of modern transportation and the clean energy transition, the demand for sustainable and lightweight materials is increasing. Composite materials incorporating natural fibers such as flax fibers have gained attention due to their carbon-capturing potential and good specific mechanical properties. However, when embedded in hydrophobic polymer matrices, flax fibers exhibit inferior mechanical performance primarily due to their hydrophilic composition and discontinuous fiber architecture. Biological materials such as nacre have developed useful strategies through mineralization to distribute localized stresses and develop extrinsic toughness that could inspire a solution to enhance stress transfer in natural fiber composites. Here, we report a biomineralization strategy to introduce an additional hierarchy to flax composites. By tuning salt concentrations in the process, we achieve controlled deposition of microbe-mediated mineral particles on flax yarns. With controlled biomineralization, we show that the minerals can enhance the compressive toughness by 178% and compressive strength by 30%. The findings highlight a novel bio-inspired pathway for tailoring composite performance through sustainable processing, offering a scalable and environmentally friendly approach to enhance natural fiber composites for structural applications.
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This study determined the relative strength of the association between fall risk factors and falls among community-dwelling older adults. Ninety-four older adults participated in this cross-sectional study. Their fall history in the past year and four categories of fall risk factors, including sensory (foot tactile sensation), motor (muscle strength and power), physical (balance, mobility, ankle range of motion, and physical activity level), and mental (fear of falling and cognitive functions), were collected. Logistic regression indicated that sensation, leg muscle power, and knee extensor strength collectively reached the highest faller status classification accuracy (70.7%). The Relative Weight Analysis results revealed that sensation accounts for 62.51% of the observed variation in faller status, followed by leg muscle power (32.49%) and knee extensor strength (5%). Our findings implied that foot sensation and leg muscle power could be used to assess one's risk of falls. Interventions targeting them may reduce falls for older adults.
Resilience is increasingly recognized as a protective factor in maternal health, yet limited research has explored how pregnant women living in low-income, immigrant-dense urban neighborhoods define and express resilience in their everyday environments. This study used photovoice to capture community-rooted strengths among pregnant participants living in Elmhurst, Queens, a multicultural area with a significant immigrant population. Ten English-speaking pregnant participants were recruited from the CHIMES (Community and Household Infant-Maternal Exposures Study), a longitudinal cohort examining environmental and psychosocial influences on maternal and child health. Participants were asked to take 10-12 photographs representing "resilience" in their neighborhoods. At a follow-up study visit, they selected up to five images to discuss in semi-structured interviews. Interview transcripts were analyzed using Braun and Clarke's six-phase thematic analysis approach, with inductive coding to identify shared themes. Four key themes emerged: (1) Nature and Outdoor Spaces as a Form of Relief, highlighting parks and green areas as calming, restorative spaces; (2) Emotional Strength through Family Connections, emphasizing support from children and relatives; (3) Community Resources as Everyday Supports, including proximity to schools, clinics, and stores; and (4) Emotional Well-being and Inner Strength, reflecting participants' mental reframing and personal growth. Participants described resilience as rooted in everyday life, grounded in social connections, local environments, and individual outlooks. These findings challenge deficit-based narratives and underscore the importance of community-informed understandings of health and coping. Photovoice revealed layered dimensions of resilience among pregnant participants, offering insight for designing maternal health interventions that build on existing community strengths.
Surfactant-coated iron oxide nanoparticles (IONPs) have been shown promising for enhancing phosphate removal in peritoneal dialysis (PD). However, the specific role of the surfactant coating in the phosphate adsorption mechanism remains to be studied, particularly for IONPS coated with anionic surfactants like tannic acid (TA) and polyacrylic acid (PAA), which exhibit significant phosphate uptake despite the presence of electrostatic repulsion. Isothermal titration calorimetry (ITC) was thus used to thermodynamically characterize phosphate adsorption on uncoated IONPs and IONPs coated with PAA, TA, and cationic polydiallyldimethylammonium chloride (PDADMAC). Such ITC interaction studies between surfactant-coated IONPs and phosphates have, to the best of our knowledge, never been reported. At first, the molar enthalpy value for the adsorption of phosphates on uncoated IONPs in pH 3 water was determined by performing complementary ITC and batch mode adsorption experiments. The phosphate adsorption was established to be exothermic with an enthalpy value of -31 kJ.mol-1 in our experimental conditions. Then, ITC experiments were conducted by adding phosphates to pH 7 water suspensions of uncoated IONPs, the three surfactant-coated IONPs, and the free surfactants (PAA, TA, and PDADMAC) alone. They confirmed that the phosphates adsorption occurred at the surface of iron oxide in surfactant coated IONPs with surfactants occupying some adsorption sites at the surface of iron oxide. However, TA was suggested to precipitate with cations introduced with each phosphate injection showing thus the sensitivity of TA coating to the ionic strength of the medium while PDADMAC, less strongly anchored to the iron oxide surface, was shown to desorb when the ionic strength increases. No reactions were observed with PAA supporting their neutral role in phosphate adsorption. These findings confirmed that phosphates can adsorb at the surface of IONPs in surfactant-coated IONPs whatever their surface charge and that surfactants coating of IONPs may be strongly affected by the ionic strength of the media. PAA coated IONPs appears as the most suitable phosphate adsorbents in our conditions.
Despite the substantial variability in physical function among older adults, the molecular mechanisms remain poorly characterized, particularly within skeletal muscle. This study aimed to determine the patterns of DNA methylation in skeletal muscle associated with physical function in healthy older adults. We analyzed DNA methylation (EPIC v2 array; 875,554 CpG sites) in skeletal muscle from 92 healthy older adults (median age 74; 62% female). Associations were examined across five phenotypes: Short Physical Performance Battery (SPPB), 6-min walk test (6MWT), handgrip strength, perceived disability (PAT-D), and lifestyle health (modified Life's Essential 8). Linear regression models adjusted for age, sex, race, BMI, and muscle fiber composition. Genomic inflation corrected via the BACON method (FDR < 0.05). Gene set enrichment analysis was performed on suggestive hits (FDR < 0.1). We identified significant differentially methylated probes (DMPs) and regions (DMRs) across all phenotypes: SPPB (70 DMPs, 22 DMRs), 6MWT (16 DMPs, 566 DMRs), handgrip strength (2 DMRs), PAT-D (19 DMPs, 1 DMR), and lifestyle health (2 DMPs). DMRs largely overlapped promoters. Identified genes overlapped known musculoskeletal and neurological GWAS hits, including RUNX2 and FOXL1 (bone mineral density), IGFBP3 (muscle mass), and NEK1 and SHANK1 (neurological function). Enrichment analysis revealed that 6MWT-associated genes relate to nervous and skeletal system development, while handgrip-associated genes involve cytoskeletal dynamics and protein assembly. Epigenetic variation in aging skeletal muscle is associated with physical function. The enrichment of pathways related to nervous and musculoskeletal development suggests specific epigenetic mechanisms underlying functional decline, offering potential targets for intervention in older adults.
Possible sarcopenia is defined by low handgrip strength in the Asian Working Group for Sarcopenia (AWGS) 2025 consensus. Whether functional recovery under these criteria improves long-term prognosis remains unclear. The study included 2761 community-dwelling participants aged ≥60 years from the China Health and Retirement Longitudinal Study (CHARLS, 2011-2018) who were free of baseline activities of daily living (ADL) disability. Participants were categorized into four trajectory subgroups based on their possible sarcopenia status in 2011 and 2013: Persistently Normal (72.0%), Reversed Possible Sarcopenia (10.8%), Progressive Possible Sarcopenia (10.8%), and Persistent Possible Sarcopenia (6.5%). Survey-weighted Cox and Fine-Gray competing risk models estimated hazard ratios (HRs) for all-cause mortality and severe ADL disability prevalent at the 2018 follow-up. During a median follow-up of 5.0 years, 258 all-cause deaths and 109 cases of prevalent severe ADL disability were documented. Persistent Possible Sarcopenia was independently associated with higher risks of all-cause mortality (HR 1.75, 95% CI 1.16-2.62) and the composite adverse outcome (HR 1.76, 95% CI 1.22-2.53), with significant ordinal trends. For the Reversed trajectory, severe ADL disability risk did not differ significantly from reference (subdistribution hazard ratio (sHR) 1.40, 95% CI 0.79-2.46). Persistently Normal handgrip strength predicts the most favorable prognosis, whereas Persistent Possible Sarcopenia carries higher risks of mortality and adverse outcomes. Whether sarcopenia reversal attenuates these risks awaits further study.
Electrospun membranes are widely used in tissue modeling because their tunable fibrous architecture can capture key structural features of the extracellular matrix of native tissues. For functional in vitro lung barrier models, membrane substrates should ideally combine stability and reproducibility with basement-membrane-relevant features, including fine fibers, reduced stiffness, and sufficient strength and extensibility to tolerate breathing-mimetic deformation. Here, poly-(ε-caprolactone) (PCL)-poly-(lactic-co-glycolic acid) (PLGA) blends were optimized to develop fully synthetic electrospun membranes that balance these competing structural and mechanical requirements. Response surface methodology (RSM) was first applied to a Box-Behnken electrospinning design, in which fiber diameter, Young's modulus, ultimate tensile strength (UTS), and strain at break were treated as coequal responses. The model predicted membranes with a fiber diameter of 0.386 ± 0.004 μm, Young's modulus of 152.156 ± 1.751 MPa, UTS of 41.850 ± 0.149 MPa, and strain at break of 2.948 ± 0.020, with confirmatory experiments deviating by less than 10% from predicted values. Machine learning (ML) extended this experimentally anchored framework by adding validated augmentation, inverse property-to-parameter prediction, and multiresponse desirability optimization. A six-generator fidelity screen selected Gaussian-Copula augmentation over WGAN-GP for downstream modeling, while leakage-free leave-one-real-observation-out evaluation showed that CatBoost most robustly recovered the polymer-composition targets, with (leave-one-out) LOO R 2 values of 0.675 for PCL concentration and 0.747 for PLGA concentration. XGBoost forward-surrogate optimization achieved the highest model-derived desirability at 0.895 ± 0.065, compared with 0.782 for the experimentally confirmed design of experiments reference. Overall, the workflow demonstrates that ML can complement RSM by prioritizing candidate electrospinning windows, quantifying uncertainty, and clarifying property-to-parameter coupling in multiresponse fibrous membrane design.
The molecular architecture (topology) of bottlebrush polymers, featuring densely grafted side chains along a polymeric backbone, leads to unique physical properties, enabling their use as functional materials including elastomers and pressure-sensitive adhesives (PSAs). Bottlebrush polymers can form additive-free PSAs due to their architecture, but most are crosslinked materials that include all-carbon backbones, have thermally unstable disulfide bonds, or do not reach the high molar masses needed for bottlebrush PSAs. Here, we applied the alternating free-radical copolymerization of sulfur dioxide (SO2) and norbornene-based macromonomers in a grafting-through approach to make bottlebrush polymers with number-average molar masses exceeding 1100 kg/mol and backbone degrees of polymerization exceeding 900. These first examples of poly(olefin sulfone) bottlebrush polymers incorporated polyacrylate, polymethacrylate, polystyrene, and poly(lactic acid) side chains, all attached to a poly(norbornene-alt-SO2) backbone. Under mild alkaline conditions, these very high molecular weight bottlebrush polymers degraded considerably within 10 min and completely within 4 h. Finally, a bottlebrush polymer synthesized using this approach behaved as a PSA with a peel strength of ∼1200 N/m, substantially higher than non-degradable PSAs in commercial tapes. In sum, this work offers a versatile approach to synthesize triggerable and degradable bottlebrush polymer adhesives enabling end-of-life disposal following their intended applications.
Persistent pulmonary air leaks contribute to prolonged hospitalization. While existing hydrogel-based sealants can be used to stop air leaks, they may lack the high elasticity needed to accommodate lung deformation and mechanical cohesion. We developed an injury-conforming sealant with an adhesion layer underneath a customized bioprinted reinforcement layer. The leak- and rupture-pressure tests demonstrated substantial improvement in adhesive and cohesive strengths of the dual-layer sealant compared to single-layer control. We also developed a computer vision-guided tracking method to quantitatively assess sealant-tissue compliance during ventilation in ex vivo swine lungs. When used to repair air leaks on ventilated swine lungs, the sealant maintained structural integrity during cyclic ventilation, exhibiting a dynamic strain of 13.4% ± 0.8% relative to 19.7% ± 0.3% in the underlying tissue. The sealant repaired the leak and restored peak-inspiratory pressure (PIP) to baseline levels (PIPNative: 30.0 ± 0.8 cmH2O; PIPInjured: 25.3 ± 0.6 cmH2O; PIPSealed: 29.5 ± 1.3 cmH2O). Collectively, our findings demonstrate that the injury-conforming dual-layer sealant effectively seals pulmonary air leak while accommodating cyclic tissue deformation during ventilation.
With their natural origin and biological compatibility, extracellular vesicles (EVs) are being recognized as next-generation vehicles for targeted drug delivery. Over the last two decades, the field of EV-based drug delivery has witnessed a substantial increase in published articles. While EVs hold tremendous potential as therapeutic carriers, their utility has been limited by issues such as heterogeneity, low yields, limited cargo loading efficiency, and rapid clearance by the mononuclear phagocyte system (MPS). In this review, we examine trends across research articles published between 2012 and 2024 (n = 38,177), focusing on key developments, persistent challenges, and evolving assumptions in the field. We provide an overview of the current EV landscape, discuss their organotropism, and discuss their application as carriers for nucleic acids and other therapeutic payloads. We highlight both their strengths and weaknesses compared to lipid nanoparticles and liposomes and assess the biodistribution of EVs as a function of labeling strategy and cell sources used. Finally, we outline translational considerations for EV-based therapeutics and propose additional reporting standards, complementing the MISEV 2023 guidelines.