This study systematically evaluates the antitumor performance of size-optimized cylindrical polymer brush (CPB) micelles—CCO-1, CCO-2, and CCO-3—in solid tumor models, with a focus on how particle dimensions influence therapeutic outcomes. The CPBs were synthesized via atom transfer radical polymerization (ATRP) using cellulose-based macroinitiators of varying chain lengths, yielding unimolecular micelles with distinct sizes (~86 nm, ~40 nm, and ~21 nm). These nanostructures combine biodegradable cellulose as a carrier, hydrophilic OEGMA for steric stabilization, and glutathione (GSH)-responsive camptothecin (CPT) as a prodrug. In vitro assessments revealed that smaller micelles exhibited significantly enhanced drug release kinetics under reducing conditions (2 mM DTT), with CCO-3 releasing over 88% of its payload within 24 hours, compared to 73.6% for CCO-1 and 80.6% for CCO-2.2,5-Diiodoterephthalic acid web This accelerated release is attributed to higher surface area-to-volume ratios and faster degradation in the intracellular redox environment. Cellular uptake studies demonstrated that CCO-3 achieved the highest internalization efficiency in HeLa cells, confirmed by flow cytometry and confocal laser scanning microscopy (CLSM), indicating that reduced size facilitates more effective cellular entry. Intracellular trafficking analysis showed that CCO-3 micelles successfully escaped endosomes, accumulated in lysosomes, and delivered CPT to mitochondria, confirming efficient organelle targeting. In three-dimensional multicellular spheroids derived from MCF-7 cells, CCO-3 penetrated deeply into the tumor core, achieving uniform distribution at a depth of 70 μm, whereas larger micelles remained largely confined to the periphery. This superior penetration ability is critical for treating heterogeneous and hypoxic tumor regions. In vivo biodistribution studies using Dir-labeled micelles revealed that while CCO-1 exhibited greater tumor accumulation due to prolonged circulation, only CCO-3 achieved deep tissue infiltration. Pharmacokinetic analysis showed shorter blood half-life for CCO-3 but significantly higher tumor drug concentration at 24 h post-injection.Goat Anti-Chicken IgY H&L Biological Activity In murine xenograft models, CCO-3 treatment resulted in the most potent antitumor effect, with a 90% inhibition rate after 12 days, surpassing CCO-1 (63%) and CCO-2 (80%). Tumor weight and volume measurements consistently supported these findings. Histopathological analysis via H&E and TUNEL staining confirmed extensive tumor cell apoptosis and necrosis in the CCO-3 group, with minimal damage observed in heart, liver, spleen, lung, and kidney tissues.PMID:35132950 Hemolysis tests indicated excellent biocompatibility, with no hemolysis even at 250 μg/mL. Routine blood analysis showed all hematological parameters within normal ranges. These results demonstrate that in solid tumors, the ability to penetrate deeply into tumor tissue outweighs the benefit of long circulation time. Therefore, optimizing particle size for enhanced diffusion and delivery is paramount. This work provides definitive evidence that for effective chemotherapy, small, rapidly releasing, and highly penetrative nanocarriers represent the optimal design strategy, offering a new paradigm for intelligent nanomedicine development.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com