Biodegradable porous micro/nanoparticles with thermoresponsive gatekeepers for effective loading and precise delivery of active compounds at the body temperature

Abstract

Stimuli-responsive controlled delivery systems are of interest for preventing premature leakages and ensuring precise releases of active compounds at target sites. In this study, porous biodegradable micro/nanoparticles embedded with thermoresponsive gatekeepers are designed and developed based on Eudragit RS100 (PNIPAM@RS100) and poly(N-isopropylacrylamide) via a double emulsion solvent evaporation technique. The effect of initiator types on the polymerization of NIPAM monomer/methylene-bis-acrylamide (MBA) crosslinker was investigated at 60 °C for thermal initiators and ambient temperature for redox initiators. The crosslinked PNIPAM plays a key role as thermal-triggered gatekeepers with high loading efficiency and precise release of a model active compound, Nile Blue A (NB). Below the volume phase transition temperature (TVPT), the gatekeepers possess a swollen conformation to block the pores and store NB within the cavities. Above its TVPT, the chains rearrange, allowing gate opening and a rapid and constant release rate of the compound until completion. A precise “on–off” switchable release efficiency of PNIPAM@RS100 was demonstrated by changing the temperatures to 4 and 40 °C. The materials are a promising candidate for controlled drug delivery systems with a precise and easy triggering mechanism at the body temperature for effective treatments.

Dual pH- and Thermo-Sensitive Poly(N-isopropylacrylamide-co-allylamine) Nanogels for Curcumin Delivery: Swelling–Deswelling Behavior and Phase Transition Mechanism

“…The experimental results indicated that the combination of dual stimuli such as pH and temperature resulted in enhanced drug release efficiency of the synthesized p(NIPAm-co-Am) NG system. In comparison to the NIPAm-based thermoresponsive copolymer-based drug delivery system reported in the literature (Table 1) [33][34][35][36][37][38][39], which focused on thermoresponsive behavior, the proposed p(NIPAm-co-Am) NG/Cur system demonstrated efficacy for dual pH and temperature-stimuli-responsive and controlled drug delivery applications. An MTT assay study was performed on MDA-MB-231 cells to determine the in vitro cytocompatibility of synthesized p(NIPAm-co-Am) NG, Cur loaded p(NIPAm-co-Am) NG/Cur, and free Cur at 37 • C. As shown in Figure 9, the p(NIPAm-co-Am) NG without Cur loading demonstrated ~92% cell viability in MDA-MB-231 cells.…”

Carbon dot-modified controllable drug delivery system for sonodynamic/chemotherapy of tumors

“…This breakdown process is beneficial as it potentially reduces the toxic side effects through in vivo metabolism during treatment. 37–39…”

“…This breakdown process is beneficial as it potentially reduces the toxic side effects through in vivo metabolism during treatment. [37][38][39] We then investigated the drug release behavior of DOX@CDs@HPMAA at different pH (7.4 and 5.0) values. The release rate and DOX amount were higher at pH 5.0 than at 7.4 within 24 hours, demonstrating its acid-responsive release ability.…”

Dispersion Performances of Naphthalimides Doped in Dual Temperature- and pH-Sensitive Poly (N-Isopropylacrylamide-co-acrylic Acid) Shell Assembled with Vinyl-Modified Mesoporous SiO2 Core for Fluorescence Cell Imaging

“…Afterward, taking the obtained PAN@BMMs-I-0.1 as an example to compare with either the pure BMMs or M-BMMs, as presented in Figure S4A (e) , the additional characteristic bands located at 1645 cm −1 , 1547 cm −1 , and 1460 cm −1 could be attributed to the C=O, N–H, and C–N stretching vibrations, respectively, which should belong to the amide group [ 47 ]. Moreover, the acromion peaks near 1716 cm −1 were attributed to the C=O stretching vibrations of the carboxylic acid groups [ 48 ].…”