Nano-biotechnology provides highly efficient and versatile strategies to improve the diagnostic precision and therapeutic efficiency of serious diseases.The development of new biomaterial systems provides great opportunities for the successful clinical translation of nano-biotechnology for personalized biomedicine to benefit patients.As a new inorganic material system,mesoporous carbon biomaterials(MCBs) combine the merits of a mesoporous nanostructure and carbonaceous composition,showing superior qualities compared with traditional mesoporous silica and other carbon-based nanosystems,such as graphene,carbon nanotubes,and fullerene.Thus,this review focuses on the rational design,chemical synthesis,and biomedical applications of MCBs.The synthetic strategies for MCBs,especially mesoporous carbon nanoparticles(MCNs),are summarized,and several representative biomedical applications of MCBs are discussed in detail.MCBs perform well for on-demand drug-release,photothermal therapy,synergistic therapy,fluorescent labeling of cancer cells,bio-adsorption of in vivo toxic pathogenic substances,peptide separation,and biosensing.The preliminary biosafety issue of MCBs is also briefly discussed.Finally,the critical issues and challenges facing the future development of MCBs for clinical translation are considered.There is great promise for MCBs to reach clinical translations for biomedical applications based on their unique nanostructure,composition,and biocompatibility once some critical issues are fully addressed.
Disruption of mitochondrial reactive oxygen species （mitoROS） plays a major role in cancer cell apoptosis. Here, we designed a core/shell-structured mitochondriatargeting upconversion-based nano-photosensitizer （TPP-UC（PS）） with a lanthanidedoped upconversion nanoparticle （UCNP） core coated by a photosensitizer （PS）-incorporated dense silica shell. Following irradiation with external nearinfrared laser （NIR）, TPP-UC（PS） in mitochondria caused serious mitochondrial matrix swelling for the activated upconversion-based photodynamic therapy （UC-PDT）, and the mobilization of cytochrome c （cyt c） was amplified in response to the increased mitoROS. Specifically, this heme-containing cyt c could be monitored by varying TPP-UC（PS）＇s upconversion luminescence signal （UCL）, which may facilitate the in situ detection of cyt c for apoptosis research. As a proof of concept, our designed TPP-UC（PS） may provide significant opportunities for controlling cancer cell apoptosis under NIR stimulation and for studying apoptosis using the dynamic UCL, which is influenced by local cyt c.
The synthesis of mesoporous material SBA-15 has been extensively reported in the past decades, which possesses a pore diameter of 6-8 nm on average. Here, a simple post-synthesis procedure has been developed to synthesize SBA-15 with further expanded pore diameter to above 10 nm simply by a solvothermal treatment replacing traditional hydrothermal step for mesopore template removal, which results in efficient pore expansion and the significantly promoted condensation of silica framework as well. This facile approach is believed applicable for pore expansions of other kinds of mesoporous silica materials.
Combination therapy is a promising cancer treatment strategy that is usually based on the utilization of complicated nanostructures with multiple components functioning as photo-thermal energy transducers, photo-sensitizers, or dose intensifiers for phototherma! therapy （PTT）, photodynamic therapy （PDT）, or radiation therapy （RT）. In this study, ultrathin tungsten oxide nanowires （W18O49） were synthesized using a solvothermal approach and examined as a multifunctional theranostic nanoplatform. In vitro and in vivo analyses demonstrated that these nanowires could induce extensive heat- and singlet oxygen-mediated damage to cancer cells under 980 nm near infrared （NIR）-laser excitation. They were also shown to function as radiation dose intensifying agents that enhance irradiative energy deposition locally and selectively during radiation therapy. Compared to NIR-induced PTT/PDT and RT alone, W18O49 - based synergistic tri-modal therapy eradicated xenograft tumors and no recurrence was observed within a 9-month follow up. Moreover, the strong X-ray attenuation ability of the tungsten element （Z = 74, 4.438 cm^2·g^-1, 100 KeV） qualified these nanowires as excellent contrast agents in X-ray-based imaging, such as diagnostic computed tomography （CT） and cone-beam CT for image-guided radiation therapy. Toxicity studies demonstrated minimal adverse effects on the hematologic system and major organs of mice within one month. In conclusion, these nanowires have shown significant potential for cancer therapy with inherent image guidance and synergistic effects from phototherapy and radiation therapy, which warrants further investigation.
