Zhiwei Li

Polymeric micelles represent a fundamental self-assembled architecture of gel-based soft materials and have emerged as promising nanocarriers for anticancer drug delivery. Their performance is largely governed by the block composition of constituent copolymers, and understanding their self-assembly behavior provides critical insights into the rational design of gel-related drug delivery systems. In this work, dissipative particle dynamics (DPD) simulations were performed to systematically investigate two types of mixed drug-loaded micellar systems self-assembled from a triblock copolymer mPEG-b-poly(2-(diethylamino)ethyl methacrylate)-b-PMMA (PDEAEMA, hereafter referred to as the DMA block for brevity) with either a diblock copolymer PDEAEMA-b-PMMA (polymer B) or PPEGMA-b-PDEAEMA (polymer C). By tailoring the ratios of hydrophobic (MMA, the constituent block of PMMA) and pH-sensitive (DMA) blocks, the protonation-responsive behavior, structural stability, drug loading capacity, and release kinetics of the micelles were comprehensively examined. The simulation results demonstrate that: (1) increasing the hydrophobic block ratio accelerates the protonation-triggered micellar swelling and drug release because the increased hydrophobic content enhances the core compactness which, upon protonation, generates a stronger driving force for chain extension, yet an optimal ratio (+16 MMA units) exists beyond which excessive hydrophobic blocks suppress release due to core densification; (2) increasing the pH-sensitive block ratio significantly enhances the maximum drug loading capacity (from 9.83% to 12.22% for the A/C system), but exerts only limited influence on the release rate; (3) the A/C mixed micelles with higher PEG content exhibit superior structural stability and drug loading capacity, while the A/B system with higher MMA content displays more sensitive pH-responsiveness. These findings reveal a competing mechanism between “protonation-driven force” and “structural resistance,” providing mesoscopic theoretical guidance for the rational design of pH-responsive polymeric nanocarriers and self-assembled soft materials via block ratio modulation.

Polymeric micelles represent a fundamental self-assembled architecture of gel-based soft materials and have emerged as promising nanocarriers for anticancer drug delivery. Their performance is largely governed by the block composition of constituent copolymers, and understanding their self-assembly behavior provides critical insights into the rational design of gel-related drug delivery systems. In this work, dissipative particle dynamics (DPD) simulations were performed to systematically investigate two types of mixed drug-loaded micellar systems self-assembled from a triblock copolymer mPEG-b-PDEAEMA-b-PMMA (polymer A) with either a diblock copolymer PDEAEMA-b-PMMA (polymer B) or PPEGMA-b-PDEAEMA (polymer C). By tailoring the ratios of hydrophobic (MMA) and pH-sensitive (DMA) blocks, the protonation-responsive behavior, structural stability, drug loading capacity, and release kinetics of the micelles were comprehensively examined. The simulation results demonstrate that: (1) increasing the hydrophobic block ratio accelerates the protonation-triggered micellar swelling and drug release, yet an optimal ratio (+16 MMA) exists beyond which excessive hydrophobic blocks suppress release due to core densification; (2) increasing the pH-sensitive block ratio significantly enhances the maximum drug loading capacity (from 9.83% to 12.22% for the A/C system), but exerts only limited influence on the release rate; (3) the A/C mixed micelles with higher PEG content exhibit superior structural stability and drug loading capacity, while the A/B system with higher MMA content displays more sensitive pH-responsiveness. These findings reveal a competing mechanism between "protonation-driven force" and "structural resistance," providing mesoscopic theoretical guidance for the rational design of pH-responsive gel-related nanocarriers and self-assembled soft materials via block ratio modulation.

In this paper, the dissipative particle dynamics (DPD) method is used to simulate the self-assembly process, appearance, mesoscopic structure, and wrapping properties of microcapsules formed with citral as the core material and chitosan and sodium alginate as the single-wall materials, and with citral as the core material and chitosan-sodium alginate, chitosan–methylcellulose, sodium alginate–chitosan, and sodium alginate–methylcellulose as the double-wall materials. The effects of chitosan content and wall material composition on the structure, morphology, encapsulation performance, and stability of microcapsules are compared and analyzed. In addition, the microcapsules are deeply analyzed by using the mesoscopic structure, radial distribution function, and diffusion coefficient. This study provides a new idea and method for the preparation of citral microcapsules, and is of great significance for the design and development of new composite wall microcapsules.

In this paper, the dissipative particle dynamics (DPD) method is used to simulate the self-assembly process, appearance, mesoscopic structure and wrapping properties of microcapsules formed with citral as the core material and chitosan and sodium alginate as single wall materials, and with citral as the core material and chitosan-sodium alginate, chitosan-methylcellulose, sodium alginate-chitosan and sodium alginate-methylcellulose as double wall materials. The effects of chitosan content and wall material composition on the structure, morphology, encapsulation performance and stability of microcapsules are compared and analyzed. In addition, the microcapsules are deeply analyzed by using the mesoscopic structure, radial distribution function and diffusion coefficient. This study provides a new idea and method for the preparation of citral microcapsules and is of great significance for the design and development of new composite wall microcapsules.