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Nanoscale materials have demonstrated a very high potential in anticancer therapy by properly adjusting their functionalization and physicochemical properties. Herein, we report the synthesis of some novel vanadocene-loaded silica-based nanomaterials incorporating four different S-containing amino acids (penicillamine, methionine, captopril, and cysteine) and different fluorophores (rhodamine B, coumarin 343 or Alexa Fluor™ 647), which have been characterized by diverse solid-state spectroscopic techniques viz; FTIR, diffuse reflectance spectroscopies, 13 C and 51 V solid-state NMR spectroscopy, thermogravimetry and TEM. The analysis of the biological activity of the novel vanadocene-based nanostructured silicas showed that the materials containing cysteine and captopril aminoacids demonstrated high cytotoxicity and selectivity against triple negative breast cancer cells, making them very promising antineoplastic drug candidates. According to the biological results it seems that vanadium activity is connected to its incorporation through the amino acid, resulting in synergy that increases the cytotoxic activity against cancer cells of the studied materials presumably by increasing cell internalization. The results presented herein hold significant potential for future developments in mesoporous silica-supported metallodrugs, which exhibit strong cytotoxicity while maintaining low metal loading. They also show potential for theranostic applications highlighted by the analysis of the optical properties of the studied systems after incorporating rhodamine B, coumarin 343 (possible) in vitro anticancer analysis, or Alexa Fluor™ 647 ( in vivo studies of cancer models)., (© 2024 IOP Publishing Ltd.)

Aims: The fight against cancer is an active research topic that combines several disciplines to find suitable agents to treat various tumours., Background: Following cisplatin, organometallic compounds, including titanocene derivatives, have been tested as antitumoral agents. However, key issues still need to be addressed in metallodrug chemotherapy relating to solubility, stability, and dosage. Mesoporous silica nanoparticles, being low toxic biocompatible materials with high loading capacity, are ideal candidates to overcome these problems., Objective: This study aimed to prepare and structurally characterize titanocene functionalized mesoporous silica nanoparticles and evaluate their cytotoxic activity against cancer cells., Methods: The preparation of titanocene functionalized mesoporous silica nanoparticles was achieved by synthetic protocols, involving either grafting or tethering. Characterization was carried out using standard techniques, FT-IR, XRD, XRF, TEM, and BET. The titanocene functionalized materials were studied as antitumoral agents in the breast cancer lines MCF-7 and MDA-MB-231., Results: The functionalized MSN showed promising antitumoral activity against cells lines MCF-7 and MDAMB- 231 up to 9 times more than titanocene alone., Conclusion: This study reported the potential of titanocene-functionalized mesoporous silica nanoparticles in future chemotherapeutic actions., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Dental caries is the major biofilm-mediated oral disease in the world. The main treatment to restore caries lesions consists of the use of adhesive resin composites due to their good properties. However, the progressive degradation of the adhesive in the medium term makes possible the proliferation of cariogenic bacteria allowing secondary caries to emerge. In this study, a dental adhesive incorporating a drug delivery system based on L-arginine-containing mesoporous silica nanoparticles (MSNs) was used to release this essential amino acid as a source of basicity to neutralize the harmful acidic conditions that mediate the development of dental secondary caries. The in vitro and bacterial culture experiments proved that L-arginine was released in a sustained way from MSNs and diffused out from the dental adhesive, effectively contributing to the reduction of the bacterial strains Streptococcus mutans and Lactobacillus casei. Furthermore, the mechanical and bonding properties of the dental adhesive did not change significantly after the incorporation of L-arginine-containing MSNs. These results are yielding glimmers of promise for the cost-effective prevention of secondary caries., (© 2022. The Author(s).)

Amyotrophic lateral sclerosis (ALS) is a devasting neurodegenerative disease with no cure to date. Therapeutic agents used to treat ALS are very limited, although combined therapies may offer a more effective treatment strategy. Herein, we have studied the potential of nanomedicine to prepare a single platform based on mesoporous silica nanoparticles (MSNs) for the treatment of an ALS animal model with a cocktail of agents such as leptin (neuroprotective) and pioglitazone (anti-inflammatory), which have already demonstrated promising therapeutic ability in other neurodegenerative diseases. Our goal is to study the potential of functionalized mesoporous materials as therapeutic agents against ALS using MSNs as nanocarriers for the proposed drug cocktail leptin/pioglitazone ( MSN-LEP-PIO ). The nanostructured materials have been characterized by different techniques, which confirmed the incorporation of both agents in the nanosystem. Subsequently, the effect, in vivo , of the proposed drug cocktail, MSN-LEP-PIO , was used in the murine model of TDP-43 proteinopathy (TDP-43 A315T mice). Body weight loss was studied, and using the rotarod test, motor performance was assessed, observing a continuous reduction in body weight and motor coordination in TDP-43 A315T mice and wild-type (WT) mice. Nevertheless, the disease progression was slower and showed significant improvements in motor performance, indicating that TDP-43 A315T mice treated with MSN-LEP-PIO seem to have less energy demand in the late stage of the symptoms of ALS. Collectively, these results seem to indicate the efficiency of the systems in vivo and the usefulness of their use in neurodegenerative models, including ALS.

A new series of theranostic silica materials based on fibrous silica particles acting as nanocarriers of two different cytotoxic agents, namely, chlorambucil and an organotin metallodrug have been prepared and structurally characterized. Besides the combined therapeutic activity, these platforms have been decorated with a targeting molecule (folic acid, to selectively target triple negative breast cancer) and a molecular imaging agent (Alexa Fluor 647, to enable their tracking both in vitro and in vivo). The in vitro behaviour of the multifunctional silica systems showed a synergistic activity of the two chemotherapeutic agents in the form of an enhanced cytotoxicity against MDA-MB-231 cells (triple negative breast cancer) as well as by a higher cell migration inhibition. Subsequently, the in vivo applicability of the siliceous nanotheranostics was successfully assessed by observing with in vivo optical imaging techniques a selective tumour accumulation (targeting ability), a marked inhibition of tumour growth paired to a marked antiangiogenic ability after 13 days of systemic administration, thus, confirming the enhanced theranostic activity. The systemic nanotoxicity was also evaluated by analyzing specific biochemical markers. The results showed a positive effect in form of reduced cytotoxicity when both chemotherapeutics are administered in combination thanks to the fibrous silica nanoparticles. Overall, our results confirm the promising applicability of these novel silica-based nanoplatforms as advanced drug-delivery systems for the synergistic theranosis of triple negative breast cancer., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Mesoporous silica nanomaterials have emerged as promising vehicles in controlled drug delivery systems due to their ability to selectively transport, protect, and release pharmaceuticals in a controlled and sustained manner. One drawback of these drug delivery systems is their preparation procedure that usually requires several steps including the removal of the structure-directing agent (surfactant) and the later loading of the drug into the porous structure. Herein, we describe the preparation of mesoporous silica nanoparticles, as drug delivery systems from structure-directing agents based on the kidney-protector drug cilastatin in a simple, fast, and one-step process. The concept of drug-structure-directing agent (DSDA) allows the use of lipidic derivatives of cilastatin to direct the successful formation of mesoporous silica nanoparticles (MSNs). The inherent pharmacological activity of the surfactant DSDA cilastatin-based template permits that the MSNs can be directly employed as drug delivery nanocarriers, without the need of extra steps. MSNs thus synthesized have shown good sphericity and remarkable textural properties. The size of the nanoparticles can be adjusted by simply selecting the stirring speed, time, and aging temperature during the synthesis procedure. Moreover, the release experiments performed on these materials afforded a slow and sustained drug release over several days, which illustrates the MSNs potential utility as drug delivery system for the cilastatin cargo kidney protector. While most nanotechnology strategies focused on combating the different illnesses this methodology emphasizes on reducing the kidney toxicity associated to cancer chemotherapy.

Parkinson's disease (PD) is a progressive neurodegenerative disease, the 2nd most common after Alzheimer's disease, the main effect of which is the loss of dopaminergic neurons. Levodopa or l-Dopa is an amino acid used in the treatment of PD that acts as the immediate precursor to dopamine. However, over time the efficacy of the medication gradually decreases requiring modified delivery methods. One of the major challenges for the medication to work is to achieve a gradual continuous supply of l-Dopa to the brain to minimise symptoms. Herein, mesoporous silica nanoparticles (MSNs) were engineered through the concept of drug-structure-directing agents (DSDAs) with inherent therapeutic activity. The DSDA used was l-Dopa drug modified by amidation with fatty acids to build anionic surfactants that were able to form micelles as templates for the assembly of inorganic precursors to form the silica framework. This templating route produced MSNs with tunable sizes ranging from 100 nm to 1 μm and with different shapes: spherical, with either solid structures with radial mesopores and porous shells, or hollow-shells with inside large void cavities; and elongated, characterized by long hollows covered by mesoporous shells. The concept of using DSDAs to synthesize drug nanocarriers can be used to avoid the surfactant removal and subsequent drug loading steps involved in the synthesis of conventional MSNs. We hypothesized that the l-Dopa released from MSN materials is mediated by the size and solubility of the DSDAs, and the surface chemical interactions between the DSDAs and MSN hosts. Different pHs (acidic and neutral) simulating gastrointestinal tract conditions were tested, and the results showed hardly any release for gastric conditions at pH 1.2, avoiding the premature release in the stomach typical of conventional MSNs, while for intestinal conditions of pH 7.4, the release of l-Dopa occurred in a continuous and sustained manner, which is well suited to the drug's application and delivery route, and matches well with achieving a sustained l-Dopa delivery to relief symptoms. This could open up new uses for MSNs synthesized by this approach to treat PD.

Hollow mesoporous silica nanoparticles (HMSNs) consist of a network of cavities confined by mesoporous shells that have emerged as promising tools for drug delivery or diagnostic. The physicochemical properties of HMSNs are dictated by the synthesis conditions but which conditions affect which property and how it impacts on biological interactions is unclear. Here by changing the concentration of the structure-directing agent (SDA), the pH and the ratio between SDA and added salt (NaCl) we determine the effects in size, morphology, surface charge and density or degree of compaction (physicochemical properties) of HMSNs and define their impact on their biological interactions with human colon cancer or healthy cells at the level of cellular uptake and viability. Increased size or density/degree of compaction of HMSNs increases their cytotoxicity. Strikingly, high salt concentrations in the synthesis medium leads to a spiky-shell morphology that provokes nuclear fragmentation and irreversible cell damage turning HMSNs lethal and unveiling intrinsic therapeutic potential. This strategy may open new avenues to design HMSNs nanoarchitectures with intrinsic therapeutic properties without incorporation of external pharmaceutical ingredients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A series of copper-functionalized SBA-15 (Santa Barbara Amorphous) materials containing the ligands triethoxysilylpropylmaleamic acid (maleamic) or triethoxy-3-(2-imidazolin-1-yl)propylsilane (imidazoline) have been prepared. The nanostructured silica-based systems SBA-maleamic, SBA-imidazoline, SBA-maleamic-Cu and SBA-imidazoline-Cu were characterized by several methods observing that the functionalization took place mainly inside the pores of the mesoporous system. The antimicrobial behaviour of the synthesized materials against Staphylococcus aureus and Escherichia coli was tested observing a very potent activity of the copper-functionalized systems (minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for SBA-maleamic-Cu of ca. 31.25 μg/mL, which correspond with ca. 1.13 μg/mL of Cu). A study of the oxidative stress promoted by the synthesized materials showed that the SBA-maleamic-Cu and the SBA-imidazoline-Cu were able to increase the reactive oxygen species (ROS) production in S. aureus by 427% and 373%, respectively, while this increase was slightly lower in E. coli (387 and 324%, respectively). Furthermore, an electrochemical study was carried out in order to determine if these materials interact with lysine or alanine to validate a potential antimicrobial mechanism based on the inhibition of the synthesis of the peptidoglycan of the bacterial wall. Finally, these studies were also performed to determine the potential interaction of the copper-containing materials with glutathione in order to assess if they are able to perturb the metabolism of this tripeptide., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2018. Published by Elsevier Inc.)

A series of nanomaterials based on mesoporous silica have been synthesised and functionalised with a photoactive polypyridyl ruthenium(ii) complex, namely [Ru(bipy)2-dppz-7-hydroxymethyl][PF6]2 (bipy = 2,2'-bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine), by various methods. The functionalisation reactions were based on the covalent binding to different ligands attached to the pores of the mesoporous nanoparticles and a simple physisorption using polyamino-functionalised mesoporous silica nanoparticles. The resulting nanostructured systems have been characterised by XRD, XRF, BET, SEM and TEM, observing the incorporation of the metallodrug onto the nanostructured silica in a different way depending on the synthetic method used in the loading reactions. In our studies, we have also observed that functionalisation with the metallodrug causes changes in the structural and textural features of the materials. The phototherapeutic activity of the ruthenium-functionalised materials in HeLa cervical cancer cells has been tested and the preliminary results are presented herein.

In the present study, we report the delivery of anti-cancer drug curcumin to cancer cells using mesoporous silica materials. A series of mesoporous silica material based drug delivery systems (S2, S4 and S6) were first designed and developed through the amine functionalization of KIT-6, MSU-2 and MCM-41 followed by the loading of curcumin. The curcumin loaded materials were characterized with several physico-chemical techniques and thoroughly screened on cancer cells to evaluate their in vitro drug delivery efficacy. All the curcumin loaded silica materials exhibited higher cellular uptake and inhibition of cancer cell viability compared to pristine curcumin. The effective internalization of curcumin in cancer cells through the mesoporous silica materials initiated the generation of intracellular reactive oxygen species and the down regulation of poly ADP ribose polymerase (PARP) enzyme levels compared to free curcumin leading to the activation of apoptosis. This study shows that the anti-cancer activity of curcumin can be potentiated by loading onto mesoporous silica materials. Therefore, we strongly believe that mesoporous silica based curcumin loaded drug delivery systems may have future potential applications for the treatment of cancers.

Gold nanoparticles were prepared using peptide-biphenyl hybrids (PBHs) as capping agents. AuNPs were characterized by different techniques including UV-Vis, TEM, EDX, FT-IR, elemental analysis, (1)H NMR and (13)C CP/MAS NMR spectroscopy. TEM analysis showed that AuNPs present diameters in the range of 1.8-3.7 nm, depending on the structure and the amount of the capping PBH used. FT-IR spectroscopy and solid-state (13)C NMR revealed that the carboxylic group of PBHs, especially in the case of the acid ligands, interacts with the gold surface (in the form of carboxylate). The results confirm that PBHs are excellent stabilizers of AuNPs, being one of the first examples on the use of peptidomimetics-gold hybrid materials., (Copyright © 2011 Elsevier Inc. All rights reserved.)