pH-Controlled Drug Release by Diffusion through Silica Nanochannel Membranes

Abstract

We report in this work the fabrication of a flow-through silica nanochannel membrane (SNM) for controlled drug release applications. The ultrathin SNM consists of parallel nanochannels with a uniform diameter of ∼2.3 nm and a density of 4 × 10 cm, which provide simultaneously high permeability and size selectivity toward small molecules. The track-etched porous polyethylene terephthalate film premodified with silane on its surface was used to support the ultrathin SNM via irreversible covalent bond formation, thus offering mechanical strength, flexibility, and stability to the ultrathin SNM for continuous and long-term use. Alkylamines were subsequently grafted onto the SNM surface to modulate the "on" and "off" state of nanochannels by medium pH for controlled drug release. Thiamphenicol glycinate hydrochloride (TPG), an intestinal drug, was studied as a model to permeate through an ultrathin SNM in both simulated gastric fluid (pH = 1.2) and simulated intestinal fluid (pH = 7.5). The release in the latter case was 178 times faster than that in the former. Moreover, a nearly zero-order constant release of TPG via single-file diffusion was achieved up to 24 h, demonstrating the feasibility of sustained and continuous release of small-molecule drugs in a pH-controlled manner.

<p>Multimodal Mesoporous Silica Nanocarriers for Dual Stimuli-Responsive Drug Release and Excellent Photothermal Ablation of Cancer Cells</p>

“…Thus, the release behavior of FS3-drug system with PDA/GO double layers was strongly dependent on the pH of surrounding solution. 62 …”

“…Thus, the release behavior of FS3-drug system with PDA/GO double layers was strongly dependent on the pH of surrounding solution. 62 Figure S4A showed the release profiles of FS3P/C and FS3P-A/C in PBS at pH 7.4 and pH 5.5, respectively. In general, the release rate of FS3P/C was faster than that of FS3P-A/C, and the release fraction at pH 5.5 was higher at pH 7.4.…”

Thermoelectric Response of Ion‐Selective Membranes: Modelling and Experimental Studies

“…The experimental details of the fabrication of SNM/PET hybrid nanochannels can be found in the Supporting information (see section S4 and Figure S2). The SNM consisting of highly ordered and vertical nanochannels was primarily grown on ITO glass by Stöber solution growth method [14a] and was then transferred to the PET membrane using PMMA‐assisted transfer technique reported recently [14b–d] . The PET membrane was employed to support SNM nanochannels.…”

<p>Intelligent Drug Delivery Microparticles with Visual Stimuli-Responsive Structural Color Changes</p>

“… 8 – 17 Microparticle DDSs are an interesting and promising option that can incorporate different types of biodegradable and biocompatible polymer components, endowing them with features such as high efficiency, good stability, low side effects and easy modification. 18 , 19 Different stimuli have been used as control switches, such as pH, 20 , 21 temperature, 22 , 23 light, 24 magnetism, 25 , 26 and electricity. 27 As one of the important stimuli, light is considered an ideal source for photo-mediated cancer therapy such as photo-thermal or photo-dynamic therapy.…”