Biocompatible Shaped Particles from Dried Multilayer Polymer Capsules

Abstract

We demonstrated a simple and facile approach to fabricate biocompatible monodisperse hollow microparticles of controlled geometry. The hemispherical, spherical, and cubical microparticles are obtained by drying multilayer capsules of hydrogen-bonded poly(N-vinylpyrrolidone)/tannic acid (PVPON/TA)n. Drying spherical capsules results in hemispherical particles if 15 < n < 20. This shape transformation is controlled by capsule stiffness, which is regulated by the layer number, capsule diameter, and PVPON molecular weight. Cubical and spherical hollow particles maintaining their three-dimensional shapes in the dry state are obtained if n ≥ 25.5. A 17-fold stiffness increase is required to lead from totally collapsed (PVPON/TA)5.5 to dried self-supporting (PVPON/TA)25.5 particles of 2 μm in dimensions. All hollow particles could be further resuspended in aqueous solutions while retaining their shapes upon rehydration. The cell growth and viability studies using human cancer cells revealed noncytotoxic properties of the (PVPON/TA) multilayer particles. Both spherical and hemispherical capsules were internalized by macrophages with the uptake of the hemispherical particles per cell two times more efficient. The method presented here allows for a robust preparation of biocompatible shaped particles whose shape and dimensions can be easily tuned by controlling capsule size and wall thickness. The reported structures can be potentially useful for biomedical applications such as shape-controlled cellular uptake and flow dynamics.

Intracellular Degradable Hydrogel Cubes and Spheres for Anti-Cancer Drug Delivery

“…35 We have lately found that rigid hydrogen-bonded tannic acid/ poly(N-vinylpyrrolidone) (TA/PVPON) hemispherical capsules produced layer-by-layer (LBL) were internalized by macrophages 2 times more efficiently that those of the spherical shape. 32 In our recent work, we also showed that red blood cell mimicking multilayer hydrogel discoidal capsules of PMAA/PVPON interacted differently with J774A.1 macrophages, HMVEC endothelial cells, and 4T1 breast cancer cells and that the discoidal capsules showed 60% lower internalization as compared to spherical capsules. 36 Despite the crucial role of particle shape in drug delivery, shaped hydrogel systems with environmental responses have been minimally explored.…”

“…The negative surface charge of the H-bonded template particles is because of the carboxyl groups within the PMAA segments not involved in H-bonding with PVPON. 32 After cross-linking with CS and release of PVPON from the multilayer hydrogel networks, the surface charge of (PMAA CS ) 5 at pH = 3 became slightly positive, yielding the ζ-potential values of 9.6 ± 0.3 and 13 ± 1 mV for the hydrogel cubes and spheres, respectively (Figure 3b). Also, in contrast to the Hbonded templates, the surface charge of the hydrogel particles was neutral at pH = 5 with the ζ-potential values oscillating around 0 mV (Figure 3b).…”

The design of wrinkled microcapsules for enhancement of release rate

“…Measured Expected This distinguishes them from other polymeric microcapsules that undergo a reversible/recoverable shape change upon re-swelling [33,34] or heating [35]. The degree of wrinkling is tunable by varying volatility (vapor pressure) of the capsule components including both blowing agents in the core and monomers in the shell compositions.…”

Nanocarriers for spleen targeting: anatomo-physiological considerations, formulation strategies and therapeutic potential

“…Chen J et al demonstrated that poly(Nvinylpyrrolidone)/tannic acid-based hemispherical microparticles revealed 2-fold higher concentration in the human cancer cells (HeLa, human cervical carcinoma cells; A549, human alveolar adenocarcinoma cells) as compared to the spheres. They suggested that the concave surface of the hemispherical microparticles could have contributed in the increased cell uptake [65].…”