A Low‐Concentration Hydrothermal Synthesis of Biocompatible Ordered Mesoporous Carbon Nanospheres with Tunable and Uniform Size

Abstract

Nanoparticles with ordered mesostructures benefit from advantages resulting from the remarkable and complementary property of the mesochannels and quantum effects in the nanoscale. Their open-framework structures, large surface area and porosity, and nanosize make ordered mesoporous nanoparticles useful in adsorption, [1][2][3] controlled drugs release, [4][5][6][7][8][9] cellular delivery, [10][11][12][13][14][15][16] energy storage, [17][18][19][20][21][22] and catalysis.[23] Among mesoporous nanoparticles, silicates have been extensively synthesized by a well-controllable process based on sol-gel chemistry. Mesoporous carbon materials have many advantages over silica materials, such as electrical conductivity, chemical inertness, hydrophobic property, which enable them to be widely used as supercapacitors, [17,18] fuel cells, [19,20] lithium batteries, [22] and hydrophobic drugs carriers.[12] Similar to silica, carbon nanoparticles are nontoxic, biocompatible, and nonimmunogenic, which allows them to be used extensively in cellular delivery. [15,16] Therefore, many efforts have been made to fabricate mesoporous carbon nanoparticles. In general, a nanocasting strategy was adopted by employing nanosized mesoporous silica as a hard template. [15,[24][25][26][27][28][29] Nevertheless, nanocasting is a very fussy, highcost, and thus industrial unfeasible method.[30] Also, the mesostructures and morphologies of the replicated carbon nanoparticles are limited to the parent silica template. However, small mesoporous carbon nanoparticles are difficult to obtain by hard-templating approach because of the aggregation and cross-linking tendency of the nanosized silicate templates and the carbon resource. [10,11] Recently, an organic-organic assembly method has been successfully developed to synthesize ordered mesoporous carbons with various structures by using amphiphilic triblock copolymers as a soft template and phenolic resol as a carbon source. [31][32][33][34][35][36][37] Two routes can be used to prepare the mesoporous carbon materials, one is the well-known evaporation induced selfassembly (EISA) method in ethanol solution, and another is aqueous solution route under a "hydrothermal" [38][39][40][41] conditions at a low temperature of 60-70 8C. Morphologies of the mesoporous carbon materials synthesized from the EISA strategy are usually films and monolithic, whereas the aqueous route usually yields powder carbon materials with particle sizes in the micrometer or millimeter scale. More recently, mesoporous carbon microspheres with the diameter over 50 mm were synthesized by a suspension assisted method, which was developed by Long and co-workers. [42] In this work, the spherical diameters were limited to micrometer-sized emulsion droplets. In this case, ordered mesoporous carbon nanoparticles are difficult to synthesize under the present conditions. To the best of our knowledge, there are no reports of the direct synthesis of ordered mesoporous carbon nanoparticles, especially nanospheres with uniform size.Herein, ...

Mesoporous carbon biomaterials

“…However, controlling the morphology and particle-size distribution of mesoporous carbon is difficult in traditional soft-templating synthesis. To solve this critical issue, Fang et al [43] recently developed a low-concentration hydrothermal process to synthesize MCNs with ordered body-centered mesoporosity, spherical morphology, and narrow size distribution. Hydrogen bonding between Pluronic F127 (EO-106 PO 70 EO 106 ; EO: ethylene oxide, PO: propylene oxide) and resols promoted the formation of spherical phenolic resol-F127 monomicelles (Fig.…”

Deactivation of sulfonated hydrothermal carbons in the presence of alcohols: Evidences for sulfonic esters formation

“…Sulfonated hydrothermal carbons, either prepared in two steps [18] or in one-pot synthetic method 3 [19], have been also used as acid catalysts for esterification reactions. Furthermore, hydrothermal carbon synthesis is a very versatile method to prepare materials with different porous structures [20][21][22][23][24] and shapes, such as hollow capsules [25][26][27], nanowires [28] or nanotubes [29]. Recently, it has been demonstrated by our group that HT carbon films can be also coated on a structured macroscopic support such as graphite felt [30].…”

Hydrophilic mesoporous carbon nanospheres with high drug-loading efficiency for doxorubicin delivery and cancer therapy

“…In this study, MCNs were synthesized through a lowconcentration hydrothermal approach according to the literature 12 with some modification. In brief, 0.6 g of phenol, 2.1 mL of formalin aqueous solution (37 wt%), and 15 mL of NaOH aqueous solution (0.1 M) were mixed and stirred at 70°C for 0.5 hours to obtain low-molecular-weight phenolic resole resins.…”

“…As shown in Figure 1, we first synthesized MCNs with spherical morphology and a diameter of 90 nm through a low-concentration hydrothermal treatment based on previous work. 12 To improve the hydrophilicity of MCNs, we introduced large amounts of oxygen-containing groups (typically hydroxyl or carboxyl groups) onto the surface of MCNs by hydrogen peroxide under mild oxidization treatments. So the oxidized MCNs were synthesized and named as oMCNs.…”