Nanomedicine Journal
Volume:7 Issue: 1, Winter 2020

Bimodal imaging combines two imaging modalities in order to benefit from their advantages and compensate the limitations of each modality. This technique could accurately detect diseases for diagnostic purposes. Nanoparticles simultaneously offer diagnostic data via various imaging modalities owing to their unique properties. Moreover, bimodal nanoprobes could be incorporated into theranostic systems for the design of multifunctional agents. Magnetic resonance imaging (MRI) and computed tomography (CT) are frequently used as noninvasive imaging modalities. These powerful, noninvasive diagnostic techniques used for the imaging of soft and hard tissues, respectively. However, MRI has low sensitivity and is not suitable for the imaging of bony structures. On the other hand, low soft tissue contrast is a major limitation of CT. Therefore, the development of various contrast agents that are proper for bimodal MRI/CT nanoprobes could largely influence modern medicine. This review aimed to specifically focus on the imaging properties of bimodal MRI/CT nanoprobes and their biomedical applications.

The present study aimed to investigate the antibacterial properties of a conventional epoxy-based dental sealer modified with synthesized bioactive glass (BG), hydroxyapatite (HA), and fluorine-substituted hydroxyapatite (FHA) nano-fillers.

The synthesized nano-fillers were incorporated into the conventional epoxy-based dental seaer at the concentration of 10%. The antimicrobial properties of the unmodified sealers (controls) and modified seaers with BG, HA, and FHA nanoparticles (NPs) were evaluated based on biofilm formation and using the direct contact test (DCT) of Enterococcus faecalis and Streptococcus mitis. Data analysis was performed using one-way analysis of variance (ANOVA) and Tukey’s post-hoc test at the significance level of 5%.

A significant reduction was observed in the biofilm formation and DCT of the microbial strains in the three modified groups compared to the unmodified conventional epoxy sealer (P<0.05). The addition of FHA NPs resulted in the most significant antibacterial effects against E. faecalis and S. mitis, as well as a statistically significant reduction compared to the unmodified and BG-modified groups (P≤0.001).

According to the results of this preliminary study, nano-structured FHA, HA, and BG fillers incorporated into epoxy-based dental sealers could be potentially effective biomaterials for antibacterial approaches to root canal treatments.

The present study aimed to fabricate chitosan/polyethylene oxide (CS/PEO) electrospun nanofibers loaded with Aloe vera extract for biomedical applications. The polymer-to-extract ratio and electrospinning parameters (applied voltage and nozzle-to-collector distance) were evaluated in order to optimize the process of nanofiber fabrication. The characterizations were performed using scanning electron microscopy (SEM), ImageJ software, attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), tensile strength test, and UV-Vis spectroscopy. The obtained results indicated that the fabrication of nanofibers from pure Aloe vera extract was unsuccessful, and reducing the extract concentration from 100% to 92% resulted in the formation of the nanofibers. Moreover, further reduction in the extract from 92% to 50% led to the production of fine nanofibers (mean diameters: 204±42 and 398±51 nm, respectively). Therefore, it was concluded that the reduced concentration of the herbal extract increased the diameters of the prepared nanofibers. In addition, the results of the optimization process indicated a direct correlation between the applied voltage and nanofiber diameters, as well as an inverse correlation between the nozzle-to-collector distance and nanofiber diameters. The FTIR spectroscopy also confirmed the presence of CS, PEO, and Aloe vera in the final prepared scaffold. The release measurement revealed a burst effect within the first five hours, followed by a sustain release within 30 hours. Moreover, the biocompatibility assay confirmed the proliferative potential of Aloe vera within seven days. According to the results, a nanofibrous scaffold composed of CS and PEO could be fabricated as the carrier of Aloe vera extract, which is a suitable platform for biomedical applications.

Attempts to produce vaccines for leishmaniasis need adjuvants to trigger the kind of immune reaction required for protection. In this study, we examined the properties of the TLR7 agonist imiquimod, a vaccine adjuvant, making use of a live model of infection where the immune reactions could be identified prior to and following the challenge of infection. The liposomes of EPC containing the imiquimod adjuvant were prepared and characterized for protein concentration, surface charge, and particle size. Vaccination was done using the soluble Leishmania antigen (SLA) as a first-generation vaccine model in the liposomal state to vaccinate BALB/c mice against the challenge of leishmania major. BALB/c mice were vaccinated subcutaneously, three times at a two-week interval. Parasite burden, footpad swelling, IgG isotype, as well as the level of IL-4 and IFN-γ were assessed as the protection criteria. The group of mice vaccinated by Lip+Imiquimod+SLA demonstrated a lower amount of footpad swelling and parasite burden than the buffer group. In addition, the highest level of IFN-γ and the lowest level of IL-4 production was noticed in the splenocytes of the mice vaccinated with the formulation of Lip+Imiquimod+SLA. These results imply that imiquimod added to the formulation of liposomes is able to modulate the immune reaction of the BALB/c mice vaccinated preferably to a Th1 reaction rather than a Th2 reaction which can also lead to partial protection against the challenge of Leishmania.

Today, there is an urgent need for improved sensor materials for drug sensing and effective monitoring and interventions in this area are highly required to struggle drug abuse. The present study aimed to synthesize a thioguanine-responsive sensor based on a nanocomposite consisting of AuNP-grafted light- and temperature-responsive poly butylmethacrylate-co-acrylamide-co-methacrylic acid ([P(BMA-co-AAm-co-MAA)] with an On/Off switching property in the presence and absence of light radiation. The incorporation of AuNPs into the structure of a polymer as the sensing moiety allows the detection of thiol-containing drug based on established gold-sulfur chemistry. The prepared nanocomposite sensor was characterized using transmission electron microscopy, scanning electron microscopy, and Fourier-transform infrared spectroscopy. In addition, the thermal sensitivity and thermal and optical switching properties of the nanocomposite were investigated. The sensor could be triggered by laser radiation at the wavelengths matched with the surface plasmon resonance (SPR) frequency of the AuNPs, providing it with an On/Off switching property. The sensor was observed to have high binding ability indicating its promising sensing applications with the wide linear responsive range of 20-250 µM and low limit of detection (0.1 µM) toward thioguanine. The prepared sensor could be used to detect the analyte in biological and pharmaceutical samples, while it is also efficient in the detection of thioguanine in actual samples.

Breast cancer is a fatal disease and the leading cause of mortality in women. Radiofrequency hyperthermia is an approach to the treatment of cancer cells through increasing their temperature. The present study aimed to investigate breast tumor ablation via radiofrequency hyperthermia in the presence and non-presence states of magnetite nanoparticles and assess the effects of magnetite nanoparticles on breast cancer treatment in hyperthermia.

Radius hemisphere geometry (5 cm) was designed, which was similar to an actual breast based on the fat tissues, glandular tissues as a semi-oval embedded in the hemisphere, and a radius sphere (1 cm) as a tumor region inside. After utilization in a three-dimensional printer, each layer of the phantom was filled with a proper combination of oil-gelatin with similar dielectric and thermal properties to an actual breast. To evaluate the effects of the magnetite nanoparticles, three weights of the magnetite were added to the tumor region (0.01, 0.05, and 0.1 g). Finally, the phantom was placed in a radiofrequency device with the frequency of 13.56 MHz.

Temperature differences were measured at four different points of the phantom. The power and time in the treatment were estimated at 40 watts and five minutes, respectively. The temperature and specific absorption rate plots were obtained for all the states in several graphs for five minutes.The results showed that the heat generation with the utilization of the magnetite state was higher by approximately 2.5-7˚C compared to the state without magnetite. Furthermore, the temperature of 0.05 gram of magnetite indicated that without causing damage in the healthy tissues, the entire tumor region could attain adequate heat uniformly (6.1-6.4˚C).

Therefore, it could be concluded that 0.05 gram of magnetite could cause ablation in the entire tumor region.

Aluminum phosphide (AlP) is commonly used pesticide which could cause poisoning mainly through the induction of oxidative stress. The present study aimed to evaluate the effects of nano-curcumin and curcumin on the oxidant and antioxidant system in the liver mitochondria using AIP-induced toxicity model. In this study, 36 male albino Wistar rats were randomly divided into six groups (n=6). The control subjects and animals poisoned with AlP (2 mg/kg) received treatment with and without nano-curcumin (100 mg/kg) and curcumin (100 mg/kg) for seven days. Mitochondria were isolated from the liver and analyzed in terms of lipid peroxidation (LPO), total antioxidant capacity (TAC), total thiol groups (TTGs), superoxide dismutase (SOD), and catalase activity. In addition, mitochondrial viability was assessed. AlP caused a significant increase in the LPO levels, while significantly decreasing TAC, TTG, SOD, catalase activity, and mitochondrial viability compared to the controls (P<0.05). Moreover, nano-curcumin treatment significantly enhanced TAC, TTG, SOD, and mitochondrial viability (P<0.05). Curcumin could also improve TTG and mitochondrial viability (P<0.05). According to the results, nano-curcumin exerted protective effects against AlP-induced experimental toxicity, and the effect was attributed to the antioxidant properties of this compound.

The present study aimed to assess the in-vitro efficacy of nanoparticulate calcium sodium phosphosilicate mouthwash in the obstruction of dentinal tubules.

This in-vitro, study was conducted on 120 sections obtained from extracted human premolars, which were etched with citric acid for two minutes and rinsed with distilled water. Afterwards, the sections were randomly divided into two groups (60 per each) of nanoparticulate and regular mouthwash. In addition, each group was divided into six subgroups of 10. In the nanoparticulate mouthwash subgroups, one subgroup (n=10) was evaluated using scanning electron microscopy (SEM). The remaining five subgroups were immersed in artificial saliva for different time periods and inspected using SEM. The control subgroups were exposed to regular mouthwash. The diameters and number of the open dentinal tubules were evaluated and compared using two-way analysis of variance (ANOVA).

The mean number of the open dentinal tubules was significantly lower in the nanoparticulate mouthwash group compared to that of the regular mouthwash group at all the time intervals (P<0.05). Moreover, the mean diameters of the open dentinal tubules were significantly smaller in the nanoparticulate mouthwash subgroups at all the time intervals (P<0.05), with the exception of four-, six-, and 12-hour intervals.

According to the results, nanoparticulate mouthwash was more effective in the obstruction of dentinal tubules compared to regular mouthwash.

Contrast-enhanced magnetic resonance imaging (MRI) of breast cancer provides valuable data on the disease state of patients. Biocompatible nanoprobes are expected to play a pivotal role in medical diagnosis in the future owing to their prominent advantages. The present study aimed to introduce a novel biocompatible nanoprobe based on lipoproteins for breast cancer cell imaging. In this study, a biocompatible nanoprobe based on high-density lipoprotein was synthesized successfully. Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS) were used for material characterization, and cellular uptake and in-vitro and in-vivo imaging were investigated using the nanoprobe. The nanoprobe could significantly reduce the relaxation time in the phantom and cancer cells with no toxicity in the studied cells. In addition, the nanoprobe demonstrated proper cellular uptake in the cancer cells. The in-vivo tumor images were obtained 30, 60, and 120 minutes after the injection of the nanoprobe (5.0 µmol/kg) via the tail vein, and the results indicated that the synthesized nanoprobe could be introduced as a potential MRI contrast agent. Future developments may allow the application of this nanoparticle to be used in pathological and physiological processes in preclinical models.

Omega-3 fatty acids play a key role in maintaining human health. The present study aimed to reduce the fishy smell and taste of omega-3 fatty acids through the encapsulation of lipid vesicles. Different non-ionic surfactants from the sorbitan ester family and egg lecithin with cholesterol were utilized to form micro-niosomal and liposomal formulations in order to encapsulate omega-3. The size of the selected microparticulate suspension was reduced using the liposome extruder. In addition, the vesicular physical stability, encapsulation efficiency (EE), release profile, and organoleptic properties were evaluated. All the amphiphiles formed omega-3 vesicles with masked omega-3 taste and smell. Span/Tween (ST) 60 niosomes had the highest EE (98.60%), while the physical stability of the liquid state forming the mixture (ST 20/cholesterol) was significantly lower compared to the other formulations. Moreover, the two-step release profile of omega-3 was achieved following entrapment in lipid bilayers. According to the results, lipid vesicular systems on the micro or nano-scale could be used to encapsulate and protect omega-3 for the production of functional foods with appropriate organoleptic properties.