L-Dopa release from mesoporous silica nanoparticles engineered through the concept of drug-structure-directing agents for Parkinson's disease

Selenium Nanoparticles as Neuroprotective Agents: Insights into Molecular Mechanisms for Parkinson's Disease Treatment

Oxidative stress and the accumulation of misfolded proteins in the brain are the main causes of Parkinson's disease (PD). Several nanoparticles have been used as therapeutics for PD. Despite their therapeutic potential, these nanoparticles induce multiple stresses upon entry. Selenium (Se), an essential nutrient in the human body, helps in DNA formation, stress control, and cell protection from damage and infections. It can also regulate thyroid hormone metabolism, reduce brain damage, boost immunity, and promote reproductive health. Selenium nanoparticles (Se-NPs), a bioactive substance, have been employed as treatments in several disciplines, particularly as antioxidants. Se-NP, whether functionalized or not, can protect mitochondria by enhancing levels of reactive oxygen species (ROS) scavenging enzymes in the brain. They can also promote dopamine synthesis. By inhibiting the aggregation of tau, α-synuclein, and/or Aβ, they can reduce the cellular toxicities. The ability of the blood-brain barrier to absorb Se-NPs which maintain a healthy microenvironment is essential for brain homeostasis. This review focuses on stress-induced neurodegeneration and its critical control using Se-NP. Due to its ability to inhibit cellular stress and the pathophysiologies of PD, Se-NP is a promising neuroprotector with its anti-inflammatory, non-toxic, and antimicrobial properties.

Promising Anticancer Prodrugs Based on Pt(IV) Complexes with Bis-organosilane Ligands in Axial Positions

We report two novel prodrug Pt(IV) complexes with bis-organosilane ligands in axial positions: cis-dichloro(diamine)-trans-[3-(triethoxysilyl)propylcarbamate]platinum(IV) (Pt(IV)-biSi-1) and cis-dichloro(diisopropylamine)-trans-[3-(triethoxysilyl) propyl carbamate]platinum(IV) (Pt(IV)-biSi-2). Pt(IV)-biSi-2 demonstrated enhanced in vitro cytotoxicity against colon cancer cells (HCT 116 and HT-29) compared with cisplatin and Pt(IV)-biSi-1. Notably, Pt(IV)-biSi-2 exhibited higher cytotoxicity toward cancer cells and lower toxicity on nontumorigenic intestinal cells (HIEC6). In preclinical mouse models of colorectal cancer, Pt(IV)-biSi-2 outperformed cisplatin in reducing tumor growth at lower concentrations, with reduced side effects. Mechanistically, Pt(IV)-biSi-2 induced permanent DNA damage independent of p53 levels. DNA damage such as double-strand breaks marked by histone gH2Ax was permanent after treatment with Pt(IV)-biSi-2, in contrast to cisplatin's transient effects. Pt(IV)-biSi-2's faster reduction to Pt(II) species upon exposure to biological reductants supports its superior biological response. These findings unveil a novel strategy for designing Pt(IV) anticancer prodrugs with enhanced activity and specificity, offering therapeutic opportunities beyond conventional Pt drugs.

Preparation of arginine-loaded mesoporous silica nanoparticles (Arg@MSNs) to improve the mechanical and antibacterial properties of denture base resin

STATEMENT OF PROBLEM

Whether the incorporation of arginine-loaded mesoporous silica nanoparticles (Arg@MSNs) into denture base resin can improve the mechanical and antibacterial properties is unclear.

PURPOSE

The purpose of this in vitro study was to synthesis Arg@MSNs and explore how Arg@MSNs incorporation affects the mechanical and antibacterial properties of denture base resin.

MATERIAL AND METHODS

Arg@MSNs were synthesized via a sol-gel process and characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). The prepared Arg@MSNs at different weight ratio concentrations were added into denture base resin as the experimental group, and unmodified denture base resin was the control. The fracture surface and arginine release behavior of each specimen were detected using scanning electron microscopy (SEM) and ultra-high-performance liquid chromatography-tandem mass spectrometer (UHPLC-HESI-MS/MS), respectively. Three-point bend tests were applied using a universal testing machine for evaluation of the mechanical properties of each group (n=5). Antibacterial efficiency (n=3) was evaluated by both quantitative and qualitative analysis using Streptococcus mutans. The cytotoxic effect of the Arg@MSN-modified denture base resin was investigated using a cell counting kit (CCK)-8 test. Data were subjected to 1-way analysis of variance followed by the post hoc Tukey honestly significant difference test (ɑ=.05).

RESULTS

The prepared Arg@MSNs had good monodispersity and spherical morphology. Arg@MSN concentration at 0.5 wt%, 1 wt%, and 2.5 wt% resulted in enhanced mechanical properties, while those at 5 wt% were adversely impacted. Biofilm pH values increased with the incorporation of Arg@MSNs, and the antibacterial performance was improved. The CCK-8 test revealed that all formulations were not cytotoxic.

CONCLUSIONS

The addition of Arg@MSNs into denture base resin can enhance its mechanical properties and improve its antibacterial performance without any apparent cytotoxic effect.

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.

Mesoporous silica nanoparticles: Their potential as drug delivery carriers and nanoscavengers in Alzheimer's and Parkinson's diseases

Worldwide, populations face significant burdens from neurodegenerative disorders (NDDs), especially Alzheimer's and Parkinson's diseases. Although there are many proposed etiologies for neurodegenerative disorders, including genetic and environmental factors, the exact pathogenesis for these disorders is not fully understood. Most patients with NDDs are given lifelong treatment to improve their quality of life. There are myriad treatments for NDDs; however, these agents are limited by their side effects and difficulty in passing the blood-brain barrier (BBB). Furthermore, the central nervous system (CNS) active pharmaceuticals could offer symptomatic relief for the patient's condition without providing a complete cure or prevention by targeting the disease's cause. Recently, Mesoporous silica nanoparticles (MSNs) have gained interest in treating NDDs since their physicochemical properties and inherent ability to pass BBB make them possible drug carriers for several drugs for NDDs treatment. This paper provides insight into the pathogenesis and treatment of NDDs, along with the recent advances in applying MSNs as fibril scavengers. Moreover, the application of MSNs-based formulations in enhancing or sustaining drug release rate, and brain targeting via their responsive release properties, besides the neurotoxicity of MSNs, have been reviewed.

L-arginine-containing mesoporous silica nanoparticles embedded in dental adhesive (Arg@MSN@DAdh) for targeting cariogenic bacteria

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.

Deciphering Dual Modes of Parkinsonian Biomolecules Derived Fluorescent Nanoparticles: Protein Specificity and White Light Generation

Dopamine (DA) and 3,4-dihydroxy-l-phenylalanine (L-Dopa or DPA), a marker and medicine for the neurological disorder Parkinson's disease (PD), lead to the formation of polymeric fluorescent nanoparticles (F-Poly NPs or F-NPs or simply, NPs). The interaction study between proteins and NPs shows prominent interaction with strong specificity toward albumin type proteins for DPA derived and mixed NPs. Furthermore, encapsulation of the anticancer drug doxorubicin hydrochloride (Dox) inside the NP-protein conjugates results in excellent white light emission with pronounced specificity toward albumin proteins for F-PDPA and F-Mix NPs. Finally, the use of BSA protein fibril resulting in strong binding with NPs along with Dox assisted white light emission has also been studied.

Therapeutic application of quercetin in aging-related diseases: SIRT1 as a potential mechanism

Quercetin, a naturally non-toxic flavonoid within the safe dose range with antioxidant, anti-apoptotic and anti-inflammatory properties, plays an important role in the treatment of aging-related diseases. Sirtuin 1 (SIRT1), a member of NAD+-dependent deacetylase enzyme family, is extensively explored as a potential therapeutic target for attenuating aging-induced disorders. SIRT1 possess beneficial effects against aging-related diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), Depression, Osteoporosis, Myocardial ischemia (M/I) and reperfusion (MI/R), Atherosclerosis (AS), and Diabetes. Previous studies have reported that aging increases tissue susceptibility, whereas, SIRT1 regulates cellular senescence and multiple aging-related cellular processes, including SIRT1/Keap1/Nrf2/HO-1 and SIRTI/PI3K/Akt/GSK-3β mediated oxidative stress, SIRT1/NF-κB and SIRT1/NLRP3 regulated inflammatory response, SIRT1/PGC1α/eIF2α/ATF4/CHOP and SIRT1/PKD1/CREB controlled phosphorylation, SIRT1-PINK1-Parkin mediated mitochondrial damage, SIRT1/FoxO mediated autophagy, and SIRT1/FoxG1/CREB/BDNF/Trkβ-catenin mediated neuroprotective effects. In this review, we summarized the role of SIRT1 in the improvement of the attenuation effect of quercetin on aging-related diseases and the relationship between relevant signaling pathways regulated by SIRT1. Moreover, the functional regulation of quercetin in aging-related markers such as oxidative stress, inflammatory response, mitochondrial function, autophagy and apoptosis through SIRT1 was discussed. Finally, the prospects of an extracellular vesicles (EVs) as quercetin loading and delivery, and SIRT1-mediated EVs as signal carriers for treating aging-related diseases, as well as discussed the ferroptosis alleviation effects of quercetin to protect against aging-related disease via activating SIRT1. Generally, SIRT1 may serve as a promising therapeutic target in the treatment of aging-related diseases via inhibiting oxidative stress, reducing inflammatory responses, and restoring mitochondrial dysfunction.

New Drug Delivery Systems Developed for Brain Targeting

The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (B_CSF) are two of the most complex and sophisticated concierges that defend the central nervous system (CNS) by numerous mechanisms. While they maintain the neuro-ecological homeostasis through the regulated entry of essential biomolecules, their conservative nature challenges the entry of most of the drugs intended for CNS delivery. Targeted delivery challenges for a diverse spectrum of therapeutic agents/drugs (non-small molecules, small molecules, gene-based therapeutics, protein and peptides, antibodies) are diverse and demand specialized delivery and disease-targeting strategies. This review aims to capture the trends that have shaped the current brain targeting research scenario. This review discusses the physiological, neuropharmacological, and etiological factors that participate in the transportation of various drug delivery cargoes across the BBB/B_CSF and influence their therapeutic intracranial concentrations. Recent research works spanning various invasive, minimally invasive, and non-invasive brain- targeting approaches are discussed. While the pre-clinical outcomes from many of these approaches seem promising, further research is warranted to overcome the translational glitches that prevent their clinical use. Non-invasive approaches like intranasal administration, P-glycoprotein (P-gp) inhibition, pro-drugs, and carrier/targeted nanocarrier-aided delivery systems (alone or often in combination) hold positive clinical prospects for brain targeting if explored further in the right direction.

A pH-responsive mesoporous silica nanoparticle-based drug delivery system for targeted breast cancer therapy

In order to make the drug specifically aggregate at the tumor site, we had developed a targeted drug delivery system based on pH responsive mesoporous silica nanoparticles. Mesoporous silica nanoparticles (MSN-COOH) were prepared and doxorubicin (DOX) was loaded into the pores of MSN-COOH, and then polyethyleneimine (PEI) and anisamide (AA) were modified on the surface of mesoporous silica, named DOX@MSN-PEI-AA(DMPA). DMPA specifically entered tumor cells through AA-mediated receptor endocytosis; PEI dissociated from the surface of the MSN in the acidic environment of cellular lysosomes/endosomes due to protonation of PEI, resulting in steady release of the encapsulated DOX from the pores of MSN in the cytoplasm of the target cells. In vitro and in vivo anti-tumor experiments and hemolytic experiments indicated that DMPA can accurately target breast cancer cells and show excellent safety at the same time, showing great potential for tumor therapy.

Nanoarchitectured prototypes of mesoporous silica nanoparticles for innovative biomedical applications

Despite exceptional morphological and physicochemical attributes, mesoporous silica nanoparticles (MSNs) are often employed as carriers or vectors. Moreover, these conventional MSNs often suffer from various limitations in biomedicine, such as reduced drug encapsulation efficacy, deprived compatibility, and poor degradability, resulting in poor therapeutic outcomes. To address these limitations, several modifications have been corroborated to fabricating hierarchically-engineered MSNs in terms of tuning the pore sizes, modifying the surfaces, and engineering of siliceous networks. Interestingly, the further advancements of engineered MSNs lead to the generation of highly complex and nature-mimicking structures, such as Janus-type, multi-podal, and flower-like architectures, as well as streamlined tadpole-like nanomotors. In this review, we present explicit discussions relevant to these advanced hierarchical architectures in different fields of biomedicine, including drug delivery, bioimaging, tissue engineering, and miscellaneous applications, such as photoluminescence, artificial enzymes, peptide enrichment, DNA detection, and biosensing, among others. Initially, we give a brief overview of diverse, innovative stimuli-responsive (pH, light, ultrasound, and thermos)- and targeted drug delivery strategies, along with discussions on recent advancements in cancer immune therapy and applicability of advanced MSNs in other ailments related to cardiac, vascular, and nervous systems, as well as diabetes. Then, we provide initiatives taken so far in clinical translation of various silica-based materials and their scope towards clinical translation. Finally, we summarize the review with interesting perspectives on lessons learned in exploring the biomedical applications of advanced MSNs and further requirements to be explored.

Cytostatic and Cytotoxic Effects of Hollow-Shell Mesoporous Silica Nanoparticles Containing Magnetic Iron Oxide

Among the different types of nanoparticles used in biomedical applications, Fe nanoparticles and mesoporous siliceous materials have been extensively investigated because of their possible theranostic applications. Here, we present hollow-shell mesoporous silica nanoparticles that encapsulate iron oxide and that are prepared using a drug-structure-directing agent concept (DSDA), composed of the model drug tryptophan modified by carbon aliphatic hydrocarbon chains. The modified tryptophan can behave as an organic template that allows directing the hollow-shell mesoporous silica framework, as a result of its micellisation and subsequent assembly of the silica around it. The one-pot synthesis procedure facilitates the incorporation of hydrophobically stabilised iron oxide nanoparticles into the hollow internal silica cavities, with the model drug tryptophan in the shell pores, thus enabling the incorporation of different functionalities into the all-in-one nanoparticles named mesoporous silica nanoparticles containing magnetic iron oxide (Fe₃O₄@MSNs). Additionally, the drug loading capability and the release of tryptophan from the silica nanoparticles were examined, as well as the cytostaticity and cytotoxicity of the Fe₃O₄@MSNs in different colon cancer cell lines. The results indicate that Fe₃O₄@MSNs have great potential for drug loading and drug delivery into specific target cells, thereby overcoming the limitations associated with conventional drug formulations, which are unable to selectively reach the sites of interest.

Kidney-Protector Lipidic Cilastatin Derivatives as Structure-Directing Agents for the Synthesis of Mesoporous Silica Nanoparticles for Drug Delivery

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.