Preparation of Sub-50 nm Colloidal Monodispersed Hollow Siloxane-Based Nanoparticles with Controlled Shell Structures

Carbon Dots-Modified Hollow Mesoporous Photonic Crystal Materials for Sensitivity- and Selectivity-Enhanced Sensing of Chloroform Vapor

Chloroform and other volatile organic pollutants have garnered widespread attention from the public and researchers, because of their potential harm to the respiratory system, nervous system, skin, and eyes. However, research on chloroform vapor sensing is still in its early stages, primarily due to the lack of specific recognition motif. Here we report a mesoporous photonic crystal sensor incorporating carbon dots-based nanoreceptor (HMSS@CDs-PCs) for enhanced chloroform sensing. The colloidal PC packed with hollow mesoporous silica spheres provides an interconnected ordered macro-meso-hierarchical porous structure, ideal for rapid gas sensing utilizing the photonic bandgap shift as the readout signal. The as-synthesized CDs with pyridinic-N-oxide functional groups adsorbed in the hollow mesoporous silica spheres are found to not only serve as the chloroform adsorption sites, but also a molecular glue that prevents crack formation in the colloidal PC. The sensitivity of HMSS@CDs-PCs sensor is 0.79 nm ppm-1 and an impressively low limit of detection is 3.22 ppm, which are the best reported values in fast-response chloroform vapor sensor without multi-signal assistance. The positive response time is 7.5 s and the negative response time 9 s. Furthermore, relatively stable sensing can be maintained within a relative humidity of 20%-85%RH and temperature of 25-55 °C. This study demonstrates that HMSS@CDs-PCs sensors have practical application potential in indoor and outdoor chloroform vapor detection.

Enhancing Methotrexate Delivery in the Brain by Mesoporous Silica Nanoparticles Functionalized with Cell-Penetrating Peptide using in Vivo and ex Vivo Monitoring

The blood-brain barrier (BBB) acts as a physical/biochemical barrier that protects brain parenchyma from potential hazards exerted by different xenobiotics found in the systemic circulation. This barrier is created by "a lipophilic gate" as well as a series of highly organized influx/efflux mechanisms. The BBB bottleneck adversely affects the efficacy of chemotherapeutic agents in treating different CNS malignancies such as glioblastoma, an aggressive type of cancer affecting the brain. In the present study, mesoporous silica nanoparticles (MSNs) were conjugated with the transactivator of transcription (TAT) peptide, a cell-penetrating peptide, to produce MSN-NH-TAT with the aim of improving methotrexate (MTX) penetration into the brain. The TAT-modified nanosystem was characterized by Fourier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and N₂ adsorption-desorption analysis. In vitro hemolysis and cell viability studies confirmed the biocompatibility of the MSN-based nanocarriers. In addition, in vivo studies showed that the MTX-loaded MSN-NH-TAT improved brain-to-plasma concentration ratio, brain uptake clearance, and the drug's blood terminal half-life, compared with the use of free MTX. Taken together, the results of the present study indicate that MSN functionalization with TAT is crucial for delivery of MTX into the brain. The present nanosystem represents a promising alternative drug carrier to deliver MTX into the brain via overcoming the BBB.