Biomimetic Silica Nanocapsules for Tunable Sustained Release and Cargo Protection

Abstract

Silica nanocapsules have attracted tremendous interest for encapsulation, protection, and controlled release of various cargoes due to their unique hierarchical core-shell structure. However, it remains challenging to synthesize silica nanocapsules having high cargo-loading capacity and cargo-protection capability without compromising process simplicity and biocompatibility properties. Here, we synthesized oil-core silica-shell nanocapsules under environmentally friendly conditions by a novel emulsion and biomimetic dual-templating approach using a dual-functional protein, in lieu of petrochemical surfactants, thus avoiding the necessities for the removal of toxic components. A light- and pH-sensitive compound can be facilely encapsulated in the silica nanocapsules with the encapsulation efficiency of nearly 100%. Release of the encapsulated active from the nanocapsules was not shown an indication of undesired burst release. Instead, the release can be tuned by controlling the silica-shell thicknesses (i.e., 40 and 77 nm from which the cargo released at 42.0 and 31.3% of the initial amount after 32 days, respectively). The release kinetics were fitted well to the Higuchi model, enabling the possibility of the prediction of release kinetics as a function of shell thickness, thus achieving design-for-purpose silica nanocapsules. Furthermore, the nanocapsules showed excellent alkaline- and sunlight-shielding protective efficacies, which resulted in significantly prolonged half-life of the sensitive cargo. Our biomimetic silica nanocapsules provide a nanocarrier platform for applications that demand process scalability, sustainability, and biocompatibility coupled with unique cargo-protection and controlled-release properties.

Evaluation of baiting fipronil-loaded silica nanocapsules against termite colonies in fields

“…4). The release of fipronil from the silica nanocapsules can fit well to the Higuchi model [4]. Fipronil release from SNC was considerably slow with 10 ± 2% on day 3 and followed by a gradual release to 25 ± 3% on day 19.…”

“…Among many applications of nanotechnology in agriculture, development of nanoscale carriers for efficient and sustainable utilities of pesticides has received a lot of attention [1, 2, 3]. Specifically, encapsulation of pesticidal active ingredients within nanocarriers enhances their deliverability to target pests and enables control over their release kinetics, while at the same time protects them from premature degradation caused by direct exposure to ultraviolet light, low pH or heat [4, 5, 6]. These integrated controlled-release and protective properties of nanocarriers are expected to facilitate better efficacy of the encapsulated pesticide by prolonging its release on a target site, as compared to non-encapsulated formulations.…”

Bioinspired Core–Shell Nanoparticles for Hydrophobic Drug Delivery

“…Thes ignificantly higher cytotoxicity of HDL NPs demonstrated their unique advantages over LDL NPs.T he drug release study of the curcumin nanocomposites showed an accelerated release of the drug at pH 4.5, but minimum release at pH 7.4 owing to the faster degradation of the silica shell in acidic solutions (Supporting Information, Figures S13 and S14). [11] Next, we performed the cytotoxicityt est on the 3D SKOV3t umor spheroids using HDL and LDL silica nanocomposites containing 100 ng mL À1 paclitaxel. [12] As we expected, after the treatment, the HDL group showed smaller spheroid volume and lower viability among all the treated groups ( Figure 4C,D;S upporting Information, Figure S15), demonstrating its enhanced tumor inhibition effect.…”

Biomimetic core–shell silica nanoparticles using a dual-functional peptide

“…We developed a novel and green biomimetic technology to form core-shell materials using dual-functional peptides [23][24][25][26][27][28][29]. These biomolecules have a unique two-module design, one module for surface activity to make stable droplets, and the other one for biosilisification activity.…”

“…After mixing, silica nanocapsules are generated with a well-controlled core-shell structure. The core size, which depends on the droplet size, can be tuned by using different homogenization energy input, different concentrations of peptide or different volume ratio of the oil phase, while the shell thickness can be controlled by adjusting the reaction time and the precursor concentration [25]. This bioinspired method is simple, sustainable, biocompatible, and doesn't involve any extreme conditions or toxic chemicals.…”