Chronic and hard-to-heal wounds remain burdensome because microbial contamination, dysregulated inflammation, and fragile tissue regeneration slow closure, while passive dressings often injure new tissue during removal. This review synthesizes polymer- and lipid-based nanostructures through a barrier-resolved lens that links composition, architecture, and processing to performance in protease- and salt-rich exudate across topical and transdermal routes. Quantitative trends include effective diameters of approximately 50–300 nm, practical constraints of sterile filtration at 0.2 μm, and therapeutic windows that prioritize contamination control on the first day, support proliferation around day three, and sustain remodeling beyond one week. Mechanistic evidence indicates that interfacial charge and the protein corona govern residence and uptake, lipid bilayers enable dual loading, degradable polymer matrices provide depot-like behavior, and hybrid constructs temper the early burst while improving storage stability.

The tumor microenvironment (TME) acts as a major barrier to effective drug delivery and contributes to drug resistance in solid tumors. Hypoxia, acidosis, and elevated interstitial fluid pressure limit drug penetration, while cancer-associated fibroblasts and immunosuppressive cells promote survival signaling, drug efflux, and metabolic adaptation. Polymeric drug delivery systems offer a promising strategy to address these barriers because their structures can be precisely engineered and designed to respond to TME-specific stimuli. These properties enable controlled drug release at tumor sites and help improve therapeutic efficacy while reducing systemic limitations. This review discusses how physicochemical and cellular components of the TME contribute to drug resistance and how polymeric nanomedicines can be designed to overcome these barriers. In addition, it examines key challenges that limit clinical translation, including tumor heterogeneity, variable enhanced permeability and retention effects, manufacturing scalability, and regulatory requirements. Finally, this review highlights the future direction of polymer nanomedicine and focuses specifically on developing rational material design, enhancing preclinical models, and developing clinically appropriate strategies to combat TME-mediated drug resistance.

This study aims to develop an integrated waste to sensor platform that couples photocatalytic PET depolymerization with on stream quantification of coexisting heavy metals. We achieve this by preparing AIM-202 through surface coordination of Ag to a water stable Zr-aspartate MOF (MIP-202), creating Ag ⁰ /Ag ^δ+ electron sink sites that enhance charge separation and reactive oxygen species generation while preserving the parent framework. The material was characterized by FT-IR, XRD, XPS, photoluminescence, KPFM, and EPR, and its photocatalytic activity was evaluated under Xe lamp irradiation. AIM-202 (5 mg mL–1) oxidized PET with increased FT-IR oxidation indices and surface pitting, and generated soluble products that increased from 151.40 µmol (week 1) to 277.27 µmol (week 2), corresponding to 11.63% and 28.68% conversion to quantified byproducts. The PET derived fluorophore 2-hydroxyterephthalate enabled fluorescence quenching based Cu ²⁺ and Fe ³⁺ sensing, and physics guided models refined with lightweight machine learning provided robust concentration back calculation. The novelty lies in a closed loop design in which MOF mediated depolymerization simultaneously produces the sensing reporter and enables data assisted quantification, supporting scalable remediation and monitoring within a single integrated scheme.

Oral vaccines must withstand gastric acid and mucus, reach microfold cells, and trigger durable mucosal IgA, but most carriers cannot simultaneously provide enteric protection, on-demand intestinal activation, and predictable biodegradation. We present magnesium-propelled polymersome (PSome) nanomotors (ActiPSomes) that conserve chemical fuel in the stomach via an enteric overcoat and activate in the intestine to enhance transport and antigen encounter. After coating, the hydrodynamic diameter increased from 141.33 ± 3.62 nm to 188.63 ± 2.03 nm, confirming formation of a protective layer. Nanoparticle-tracking analysis showed negligible directional motion under gastric conditions (pH 2.0) but pronounced propulsion at intestinal pH (pH 8.0); the size mobility relationship followed MSD theory with R² ≈ 0.96. In vitro, ActiPSomes increased macrophage uptake of Nile-red-labeled antigen ∼2.8-fold versus particles without magnesium and maintained a ∼2.1-fold advantage after sequential exposure to simulated gastric and intestinal environments. In vivo, oral dosing elicited significantly higher PEDV-specific IgA titers in feces and intestines at days 7 and 14 compared with controls (p < 0.05-0.001), with no adverse clinical signs or weight loss over 14 days. Mechanistically, intestinal pH dissolves the enteric layer to expose intravesicular Mg, generating hydrogen that drives active diffusion while PLA hydrolysis supports intestinal biodegradation. These data establish a generalizable nanoplatform for enteric-protected, fuel-efficient oral vaccination against mucosal pathogens. In this study, we developed magnesium-propelled PSome nanomotors, termed ActiPSomes, that integrate enteric protection, pH-triggered propulsion, and intestinal biodegradation to enhance oral antigen delivery and mucosal immunity.

Targeted drug delivery remains difficult because multiple biological barriers interfere with the stable transport of therapeutics to the site of action. Polymeric nanocarriers have gained broad attention as delivery platforms since their composition and surface properties can be adjusted to improve circulation behavior and cellular delivery. This review discusses the major biological barriers involved in targeted drug delivery and describes how polymeric nanocarriers are engineered to overcome them. Major carrier types, including polymeric nanoparticles and micelles, are considered with emphasis on their physicochemical and interfacial features. Particular attention is given to surface engineering and stimuli-responsive design as key strategies for barrier transport and controlled cargo release. The review also highlights representative applications in anticancer, gene, protein, and vaccine delivery, together with translational issues such as biocompatibility, stability, reproducibility, scale-up, and regulatory acceptance.