A series of nanospherical shaped silicates containing heteroatoms (Al, Zr or Ti) were successfully synthesized using TEOS or silica colloids as silicon source. These metallosilicate nanospheres were used as silicon nutrients to obtain silicalite zeolites having micro-mesoporosity with improved textural properties. The results demonstrated that TEOS acted as a suitable silicon source to produce amorphous silicates and a spherical-type hierarchical zeolite architecture with Zr and Ti heteroatoms included in their framework, with preferable particle size and crystallinity. The surface functionality of the mesostructured nanospheres and zeolite silicates provide active centers for the esterification of glycerol with acetic acid (EG) reaction. Besides, the dispersion of Cu or Fe entities on the surface of the nanospherical silicates and zeolites provided good catalytic performances in the esterification of glycerol to valuable acetins.

Chitosan is a biodegradable polymer derived from chitin, that is a versatile material for various biological applications for its attractive properties such as biocompatibility, biodegradability, and non-toxicity. Furthermore, chitosan possesses Second Harmonic Generation properties, that are useful for bio-sensing applications. In this work we explored the possibility to exploit chitosan-based nanospheres as SHG-based bio-sensors, and also as carriers of 89Sr radionuclide, an Active Pharmaceutical Ingredient for radiopharmaceutical treatments in cancer therapy. To load opportunely the Sr ion on the nanospheres, we used a fructose-based Metal Organic Framework, of formula [Sr(C6H12O6)2(H2O)2]Cl2·H2O, because the sugar was able to drive the Sr ions on the chitosan matrix. The Sr-loaded chitosan nanospheres were synthetized, characterized, and their SHG response was measured. The results encouraged us to propose the nanospheres for theranostic purposes, i.e. at the same time valuable for both therapy and diagnostic applications.

Some peptide-based drugs including oxytocin, vasopressin, ziconotide, pramlintide, nesiritide, and octreotide, contain one intramolecular disulfide bonds. A novel and reusable monodispersed silica nanosphere-supported Pt(IV) complex (SiO2@TPEA@Pt(IV)) was synthesized via a four-step procedure and used for formation of intramolecular disulfide bonds in peptides. TEM and chemical mapping results for the Pt(II) intermediates and for SiO2@TPEA@Pt(IV) show that the silica nanospheres possess a monodisperse spherical structure and contain uniformly distributed Si, O, C, N, Cl, and Pt. The valence state of Pt on the silica nanospheres was characterized by XPS. The Pt(IV) loaded on SiO2@TPEA@Pt(IV) was 0.15 mmol/g, as determined by UV-vis spectrometry. Formation of intramolecular disulfides in six dithiol-containing peptides of variable lengths by use of SiO2@TPEA@Pt(IV) was investigated and the relative oxidation yields were determined by HPLC. In addition, peptide 1 (Ac-CPFC-NH2) was utilized to study the reusability of SiO2@TPEA@Pt(IV). No significant decrease in the relative oxidation yield was observed after ten reaction cycles. Moreover, the structure of SiO2@TPEA@Pt(IV) after being used ten cycles was determined to be similar to its initial one, demonstrating the cycling stability of the complex.

Surface-enhanced Raman spectroscopy (SERS) can boost the pristine Raman signal by ~ 108 times that could be exploited for producing innovative sensing devices with advanced properties. However, the inherent complexity of SERS systems restricts their further applications in rapid detection, especially in situ detection in narrow aera. Here, we construct an efficient and flexible SERS-based LOP sensor by integrating Ag/Au nanocap arrays obtained by Ag/Au coating polystyrene nanospheres on the optical fiber face. We obtain rich “hotspots” at the nanogaps between neighboring nanocaps and further achieve the excellent SERS performance with the assistance of laser induced thermophoresis on the metal film that can achieve high efficiency aggregation of detected molecules. We achieve a high Raman enhancement with a low detection limitation of 10-7 mol/L for the most efficient samples based on the above sensor. This sensor also exhibits good repeatability and stability under multiple detections, revealing the potential application in situ detection based on the reflexivity of optical fiber.