Amino Acid-functionalized hollow mesoporous silica nanospheres as efficient biocompatible drug carriers for anticancer applications

Design of Scaffolds Based on Zinc-Modified Marine Collagen and Bilberry Leaves Extract-Loaded Silica Nanoparticles as Wound Dressings

Purpose

In this study, wound dressings were designed using zinc-modified marine collagen porous scaffold as host for wild bilberry (WB) leaves extract immobilized in functionalized mesoporous silica nanoparticles (MSN). These new composites were developed as an alternative to conventional wound dressings. In addition to the antibacterial activity of classic antibiotics, a polyphenolic extract could act as an antioxidant and/or an anti-inflammatory agent as well.

Methods

Wild bilberry leaves extract was prepared by ultrasound-assisted extraction in ethanol and its properties were evaluated by UV-Vis spectroscopy (radical scavenging activity, total amount of polyphenols, flavonoids, anthocyanins, and condensed tannins). The extract components were identified by HPLC, and the antidiabetic properties of the extract were evaluated via α-glucosidase inhibitory activity. Spherical MSN were modified with propionic acid or proline moieties by post-synthesis method and used as carriers for the WB leaves extract. The textural and structural features of functionalized MSN were assessed by nitrogen adsorption/desorption isotherms, small-angle XRD, SEM, TEM, and FTIR spectroscopy. The composite porous scaffolds were prepared by freeze drying of the zinc-modified collagen suspension containing WB extract loaded silica nanoparticles.

Results

The properties of the new composites demonstrated enhanced properties in terms of thermal stability of the zinc-collagen scaffold, without altering the protein conformation, and stimulation of NCTC fibroblasts mobility. The results of the scratch assay showed contributions of both zinc ions from collagen and the polyphenolic extract incorporated in functionalized silica in the wound healing process. The extract encapsulated in functionalized MSN proved enhanced biological activities compared to the extract alone: better inhibition of P. aeruginosa and S. aureus strains, higher biocompatibility on HaCaT keratinocytes, and anti-inflammatory potential demonstrated by reduced IL-1β and TNF-α levels.

Conclusion

The experimental data shows that the novel composites can be used for the development of effective wound dressings.

Vancomycin Loaded Amino-Functionalized MCM-48 Mesoporous Silica Nanoparticles as a Promising Drug Carrier in Bone Substitutes for Bacterial Infection Management

Orthopedic infections due to biofilm formation in biomaterial-based implants have become challenging in bone tissue engineering. In the present study, in vitro antibacterial analysis of amino-functionalized MCM-48 mesoporous silica nanoparticles (AF-MSNs) loaded with vancomycin is analyzed for its potential as a drug carrier for the sustained/controlled release of vancomycin against Staphylococcus aureus. The effective incorporation of vancomycin into the inner core of AF-MSNs was observed by alternation in the absorption frequencies obtained by Fourier transform infrared spectroscopy (FTIR). Dynamic light scattering (DLS) and high resolution-transmission electron microscopy (HR-TEM) results show that all the AF-MSNs had homogeneous spherical shapes with a mean diameter of 165.2 ± 1.25 nm, and there is a slight change in the hydrodynamic diameter after vancomycin loading. Furthermore, the zeta potential of all the AF-MSNs (+ 30.5 ± 0.54 mV) and AF-MSN/VA (+ 33.3 ± 0.56 mV) were positively charged due to effective functionalization with 3-aminopropyl triethoxysilane (APTES). Furthermore, cytotoxicity results show that the AF-MSNs have better biocompatibility than non-functionalized MSNs (p < 0.05), and results prove AF-MSNs loaded with vancomycin show better antibacterial effect against S. aureus than non-functionalized MSNs. Results confirm that bacterial membrane integrity was affected by treatment with AF-MSNs and AF-MSN/VA by staining the treated cells with FDA/PI. Field emission scanning electron microscopy (FESEM) analysis confirmed the shrinkage of bacterial cells and membrane disintegration. Furthermore, these results demonstrate that amino-functionalized MSNs loaded with vancomycin significantly increased the anti-biofilm and biofilm inhibitory effect and can be incorporated with biomaterial-based bone substitutes and bone cement to prevent orthopedic infections post-implantation.

High cancer selectivity and improving drug release from mesoporous silica nanoparticles in the presence of human serum albumin in cisplatin, carboplatin, oxaliplatin, and oxalipalladium treatment

In this project, drug release was examined based on the adsorption of cisplatin, carboplatin, oxaliplatin, and oxalipalladium on aminated mesoporous silica nanoparticles (N-HMSNs) and human serum albumin (HSA). These compounds were characterized by different techniques where three clinical Pt-drugs, cisplatin, carboplatin, oxaliplatin, plus oxalipalladium were loaded and investigated for release. Based on loading analysis, the loading ability of the mentioned metallodrug on N-HMSNs was dependent on the nature of the drug structure as well as hydrophobic or hydrophilic interactions. Different adsorption and release profiles were observed for all mentioned compounds via dialysis and ICP method analysis. Although the maximum to minimum loading occurred for oxalipalladium, cisplatin, and oxaliplatin to carboplatin, respectively, release from a surface with greater control belonged to carboplatin to cisplatin systems in the absence and presence of HSA to 48 hours due to weak interaction for carboplatin drug. The quick release of all mentioned compounds from the protein level at high doses of the drug during chemotherapy occurred very fast within the first 6 hours. In addition, the cytotoxic activity of both free drugs and drug-loaded@N-HMSNs samples on cancerous MCF-7, HCT116, A549, and normal HFF cell lines was evaluated by MTT assay. It was found that free metallodrugs exhibited more active cytotoxic behavior on both cancerous and normal cell lines than drug-loaded@N-HMSNs. Data demonstrated that the Cisplatin@N-HMSNs with SI=6.0 and 6.6 for MCF7 and HCT116 cell lines, respectively, and Oxaliplatin@N-HMSNs with SI=7.4 for HCT116 cell line can be good candidates as an anticancer drug with minimal side effects by protecting cytotoxic drugs as well as controlled release and high selectivity.

Endogenous NO-release multi-responsive hollow mesoporous silica nanoparticles for drug encapsulation and delivery

Novel multi-responsive drug delivery vehicles (CDs/PNVCL@HMSNs) were prepared by grafting amino-terminated poly (N-vinyl caprolactam) (PNVCL-NH₂) and amino-rich carbon dots (CDs) on the surface of aldehyde-functionalized HMSNs (HMSNs-CHO) via Schiff base reaction. The CDs were prepared from L-arginine and their surfaces were rich in guanidine. Doxorubicin (DOX) was loaded into the nanoparticles to form drug loaded vehicles (CDs/PNVCL@HMSNs-DOX) and the drug loading efficiency was 58.38%. The drug release behaviors of CDs/PNVCL@HMSNs-DOX showed temperature and pH responsiveness due to the poly (N-vinyl caprolactam) (PNVCL) and Schiff base bond. The high concentration of NO released in high concentration H₂O₂ of tumor site could induce tumor cells apoptosis. The multi-responsive CDs/PNVCL@HMSNs are intriguing drug carriers, which combine drug delivery and NO release in one.

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.

Architecture of Nanoantioxidant Based on Mesoporous Organosilica Trp-Met-PMO with Dipeptide Skeleton

A nanoantioxidant of mesoporous organosilica (Trp-Met-PMO) based on the framework of tryptophan-methionine dipeptide was first designed and constructed by condensation between self-created dipeptide organosilica precursor (Trp-Met-Si) and tetraethyl orthosilicate (TEOS) in alkaline conditions under the template hexadecyl trimethyl ammonium bromide (CTAB). Trp-Met-Si was prepared by the reaction between dipeptide Trp-Met and conventional organosilicon coupling agent isocyanatopropyltriethoxysilane (IPTES) via a multiple-step reaction method. The material Trp-Met-PMO was confirmed by XRD, FT-IR and N₂ adsorption-desorption analysis. The material Trp-Met-5-PMO with low amounts of organosilica precursor remained a mesoporous material with well-ordered 2D hexagonal (P6mm) structure. With increasing amounts of organosilica precursor, a mesoporous structure was still formed, as shown in the material Trp-Met-100-PMO with the highest amounts of organosilica precursor. Moreover, pore size distribution, surface area and porosity of Trp-Met-PMO are regulated with different amounts of organosilica precursor Trp-Met-Si. The antioxidant activity of Trp-Met-PMO was evaluated by ABTS free radical-scavenging assay. The results showed that antioxidant activity was largely enhanced with increasing contents of organosilica precusor Trp-Met-Si in the skeleton. The material Trp-Met-40-PMO exhibited maximum scavenging capacity of ABTS free radicals, the inhibition percent was 5.88%. This study provides a design strategy for nanoantioxidant by immobilizing short peptides within the porous framework of mesoporous material.

The emergence of nanoporous materials in lung cancer therapy

Lung cancer is one of the most common cancers, affecting more than 2.1 million people across the globe every year. A very high occurrence and mortality rate of lung cancer have prompted active research in this area with both conventional and novel forms of therapies including the use of nanomaterials based drug delivery agents. Specifically, the unique physico-chemical and biological properties of porous nanomaterials have gained significant momentum as drug delivery agents for delivering a combination of drugs or merging diagnosis with targeted therapy for cancer treatment. This review focuses on the emergence of nano-porous materials for drug delivery in lung cancer. The review analyses the currently used nanoporous materials, including inorganic, organic and hybrid porous materials for delivering drugs for various types of therapies, including chemo, radio and phototherapy. It also analyses the selected research on stimuli-responsive nanoporous materials for drug delivery in lung cancer before summarizing the various findings and projecting the future of emerging trends. This review provides a strong foundation for the current status of the research on nanoporous materials, their limitations and the potential for improving their design to overcome the unique challenges of delivering drugs for the treatment of lung cancer.

Fine-tuning pharmacological properties of mirtazapine antidepressant drug: a theoretical study

It has become obvious that fluorinated drugs have a significant role in medicinal applications. In this study, the fluorination of mirtazapine antidepressant drug was investigated using density functional theory calculations. We found that the intramolecular hydrogen bonding and charge transfers of the mirtazapine drug were influenced by fluorine substitution. Our results also reveal that the fluorination altered the stability, solubility, and molecular polarity of the mirtazapine antidepressant drug. Moreover, our results show that the electronic spectra of fluorinated derivatives of the mirtazapine exhibit a red shift toward higher wavelengths compared to the original antidepressant drug. Our calculations show that the difference between G value of the gas and water (ΔG) of fluorinated derivatives of the mirtazapine drug was negative. We also found that the fluorination can increases the first hyperpolarizability of the mirtazapine antidepressant drug. Our results present an efficient strategy to improve the nonlinear optical responses of the antidepressant drugs. Consequently, the results of present study show that the fluorination of mirtazapine could be considered as a promising strategy to design antidepressant drugs with better pharmacological properties.Communicated by Ramaswamy H. Sarma.

Nitrile-containing copper(ii) porphyrin coordination complexes for efficient anticancer activity and mechanism research

Synthesis and anticancer activity of nitrile-containing copper(ii) porphyrin coordination complexes.

Novel Biocompatible Amino Acids-Functionalized Three-dimensional Graphene Foams: As the Attractive and Promising Cisplatin Carriers for Sustained Release Goals

Application of amino acids-immobilized porous materials for drug delivery studies has been attracted a lot of attention in the recent years. In this study, amino acids-grafted graphene foams were prepared by anchoring of Alanine (Ala), Cysteine (Cys) and Glycine (Gly) amino acids on the surface of graphene oxide (GO) nanostructures and used as the novel biocompatible carriers to control releasing of the cisplatin as the cytotoxic anticancer drug. The characterization of prepared compounds was done by the FT-IR, Raman, TGA, N₂ adsorption-desorption isotherms, SEM, and TEM techniques. Adsorption and in vitro release behavior of amino acids-functionalized foams were studied using ICP standard method. The results show that the drug loading amount and the drug releasing rate are significantly enhanced upon functionalization process. The Ala-Foam sample with the larger surface area and pore volume showed a higher loading content (4.53%) than other samples. In addition, the MTT test on the two MCF-7 and HepG2 human cancer cell lines exhibited an acceptable biocompatibility and sustainable drug releasing from the carriers up to 48 h, leading to the dosage frequency decrease and the patient compliance improvement.

Biodegradable Mesoporous Organosilica Nanosheets for Chemotherapy/Mild Thermotherapy of Cancer: Fast Internalization, High Cellular Uptake, and High Drug Loading

The choice of nanocarriers is crucial to fabricate ideal therapeutic nanoplatform in the treatment of cancer. Considering the advantages brought by the two-dimensional (2D) materials with atomic thickness in drug loading and cellular uptake, herein, novel 2D biodegradable mesoporous organosilica nanosheets (MONSs) are presented, and their application in chemotherapy/mild thermotherapy of cancer is studied by loading chemotherapy drug doxorubicin (DOX) and conjugating ultrasmall CuS nanoparticles. It is found that the loading of DOX in MONSs is as high as 859 μg/mg due to their large surface area and intermediate void structure. The release of DOX from MONSs is intelligently controlled by pH value, glutathione (GSH) concentration, and laser irradiation. Excitingly, in comparison with traditional spherical mesoporous organosilica nanoparticles, as-prepared MONSs not only show more rapid degradation but also exhibit faster internalization and higher cellular uptake efficiency due to their larger aspect ratios and unique cellular internalization approach of 2D materials. A mild thermotherapy induced by ultrasmall CuS nanoparticles can further promote the cellular uptake and improve chemotherapy efficacy. The in vitro and in vivo experimental results reveal that the theranostic nanoplatform based on degradable MONSs has excellent biocompatibility and anticancer effects. Therefore, MONSs are expected to be a competitive alternative to existing silica-based nanomaterials in antitumor treatment.

Fluorinated-antioxidant derivatives with improved pharmacological activity: a theoretical study

It has become obvious that fluorinated drugs have a significant role in medicinal applications. In this study, the fluorination of ferulic acid (FA) antioxidant was investigated using density functional theory calculations. We have explored the most important chemical properties of FA that affects the pharmacological activity of antioxidant. We found that the intramolecular hydrogen bonding and charge transfers of the FA were influenced by fluorine substitution. Our results also reveal that the fluorination altered the stability, solubility and molecular polarity of the FA. Moreover, our results show that the electronic spectra of fluorinated derivatives of FA exhibit the red and blue shifts toward higher and lower wavelengths, respectively, compared to the original FA. Our calculations show that the free energy transfer of fluorinated derivatives of the FA in water was negative that it meant that the designed molecules dissolving in aqueous phase occurred simultaneously. We also found that the fluorination can increase the first hyperpolarizability of the FA. Our results present an efficient strategy to improve the nonlinear optical responses of the antioxidants. Consequently, the results of present study show that the fluorination of FA could be considered as a promising strategy to design useful drugs with better pharmacological properties.[Formula: see text]Fluorination is an effective strategy to improve pharmacological activity of frulic acid antioxidant.Communicated by Ramaswamy H. Sarma.