Supertough Hybrid Hydrogels Consisting of a Polymer Double‐Network and Mesoporous Silica Microrods for Mechanically Stimulated On‐Demand Drug Delivery

Abstract

Despite their potential in various fields of bioapplications, such as drug/ cell delivery, tissue engineering, and regenerative medicine, hydrogels have often suffered from their weak mechanical properties, which are attributed to their single network of polymers. Here, supertough composite hydrogels are proposed consisting of alginate/polyacrylamide double-network hydrogels embedded with mesoporous silica particles (SBA-15). The supertoughness is derived from efficient energy dissipation through the multiple bondings, such as ionic crosslinking of alginate, covalent crosslinking of polyacrylamide, and van der Waals interactions and hydrogen bondings between SBA-15 and the polymers. The superior mechanical properties of these hybrid hydrogels make it possible to maintain the hydrogel structure for a long period of time in a physiological solution. Based on their high mechanical stability, these hybrid hydrogels are demonstrated to exhibit on-demand drug release, which is controlled by an external mechanical stimulation (both in vitro and in vivo). Moreover, different types of drugs can be separately loaded into the hydrogel network and mesopores of SBA-15 and can be released with different speeds, suggesting that these hydrogels can also be used for multiple drug release.

Adhesive Hydrogel Patch with Enhanced Strength and Adhesiveness to Skin for Transdermal Drug Delivery

“…Previous studies have reported that the mechanical property of hydrogels can be enhanced by incorporating inorganic fillers, owing to the molecular interactions between polymer chains and the surface of inorganic fillers. [13,[34][35][36][37][38][39][40][41] We first hypothesized that the incorporation of mesoporous silica nanoparticles with high surface areas can contribute toward enhancing the cohesion property of the PAM/PDA hydrogels while maintaining their adhesive property. We synthesized mesoporous silica nanoparticles with extra-large mesopores (XL-MSNs) for this purpose.…”

Organic–Inorganic Copolymerization for a Homogenous Composite without an Interphase Boundary

“…[18] In Raman spectra, there is ashift of PÀOstretch mode from 953 cm À1 in CaP to 967 cm À1 in PCC, which can also be understood by the hydrogen bond interaction (Figure 2b). [19] Them olecular interactions between the organic and inorganic components are further confirmed by 13 Ca nd 1 Hs olid-state NMR spectra (Figure 2c,d;S upporting Information, Figure S1): the typical carbon peaks of acylamino group (246.435 ppm) and a-C (179.055 ppm) in pure PA Ms hift to 248.555 ppm and 179.633 ppm, respectively,i nP CC.M oreover,t he hydrogen peaks of acylamino group (23.568 ppm), a-H (3.918 ppm), and b-H (1.507 ppm) in pure PA Mm ove to 24.150 ppm, 4.088 ppm and 1.735 ppm, respectively,inPCC.DSC analysis provides another indicative evidence (Supporting Information, Figure S2). Ac onventional organic and inorganic composite of PA Mand CaP is prepared by mixing amorphous calcium phosphate nanoparticles (NP,d iameters of about 80 nm;S upporting Information, Figure S3) into PA Md uring the organic polymerization, which is defined as PA M-NP.I n this conventionally obtained composite,t he endothermal peak of PA M( around 54 8 8C) is not affected by the added inorganic phase.I tf ollows that there is no chemical interaction between PA Ma nd NP in PA M-NP.H owever,t his temperature increases to 56 8 8Ci nP CC,i mplying ac hemical Figure 1.…”

“…[11] However,p ure PA Mm aterials cannot reach an appropriate toughness to ensure their application. Va rious nanomaterials (such as grapheme oxide, [12] mesoporous silica particles, [13] and cellulose nanofibers [14] )h ave been used to reinforce their mechanical strengths.H owever,t he boundaries between different component phases in these composites remain so that the improvements are still limited. It is documented that the highest hardness and modulus of the PA M-based composites are 0.95 GPa and 16.92 GPa, respectively.…”

“…To confirm the suggested copolymer structure,attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman, and solid-state 13 Ca nd 1 Hn uclear magnetic resonance (NMR) are used to investigate the organic-inorganic chemical interactions within the PCC bulk. In ATR-FTIR profiles (Figure 2a), the characteristic peak of PÀOs tretching vibration locates at 1012 cm À1 in the pure CaP sample but this peak shifts to 1045 cm À1 in PCC, implying the formation of N À H···O network between PA M and the ultrasmall CaP.…”

Organic–Inorganic Copolymerization for a Homogenous Composite without an Interphase Boundary

“…However, pure PAM materials cannot reach an appropriate toughness to ensure their application. Various nanomaterials (such as grapheme oxide, mesoporous silica particles, and cellulose nanofibers) have been used to reinforce their mechanical strengths. However, the boundaries between different component phases in these composites remain so that the improvements are still limited.…”