ABSTRACT
Gene therapeutics are promising for treating diseases at the genetic level, with some already validated for clinical use. Recently, nanostructures have emerged for the targeted delivery of genetic material. Nanomaterials, exhibiting advantageous properties such as a high surface-to-volume ratio, biocompatibility, facile functionalization, substantial loading capacity, and tunable physicochemical characteristics, are recognized as non-viral vectors in gene therapy applications. Despite progress, current non-viral vectors exhibit notably low gene delivery efficiency. Progress in nanotechnology is essential to overcome extracellular and intracellular barriers in gene delivery. Specific nanostructures such as carbon nanotubes (CNTs), carbon quantum dots (CQDs), nanodiamonds (NDs), and similar carbon-based structures can accommodate diverse genetic materials such as plasmid DNA (pDNA), messenger RNA (mRNA), small interference RNA (siRNA), micro RNA (miRNA), and antisense oligonucleotides (AONs). To address challenges such as high toxicity and low transfection efficiency, advancements in the features of carbon-based nanostructures (CBNs) are imperative. This overview delves into three types of CBNs employed as vectors in drug/gene delivery systems, encompassing their synthesis methods, properties, and biomedical applications. Ultimately, we present insights into the opportunities and challenges within the captivating realm of gene delivery using CBNs.
ABSTRACT
In the present work, single wall carbon nanotubes (SWCNT) were successively functionalized with phospholipid DSPE-PEG carboxylic acid, and then, with ethylenediamine (EDA), to obtain double functionalized single wall carbon nanotube (DFSWCNT). Then, DFSWCNT was applied as a carrier for delivering amphotericin B (Amb) and EGFP plasmid. FSWCNT's concentration obtained via UV-visible analysis was 0.99 mg/mL. The TGA analysis results provided the lost weights of DSPE-PEG-COOH, EDA, Amb and SWCNT impurities. XPS results showed that carbon atoms' percentage decreased during the functionalization processes from 97.2% (SWCNT) to 76.4% (FSWCNT) and 69.9% (DFSWNCT). Additionally, the oxygen atoms' percentage increased from 2.3% (SWCNT) to 21% and 22.5% for FSWCNT and DFSWCNT, respectively. New bonds such as C-N and N-C=O appeared in the synthesized nanocarrier. The IG/ID ratio in Raman analysis decreased from 7.15 (SWCNT) to 4.08 (FSWCNT). The amount of Amb released to phosphate buffer saline medium was about 33% at pH = 5.5 and 75% at pH = 7.4 after 48 h. CCK8 results confirmed that the toxicity of functionalized SWCNT had decreased. In a 2:1 ratio of DFSWCNT/EGFP plasmid, the cell viability (87%) and live transfected cells (56%) were at their maximum values. The results indicate that carbon nanotubes have the potential to be applied as drug/gene delivery systems with outstanding properties such as high loading capacity and easy penetration to cell membrane.
Subject(s)
Nanotubes, Carbon , Amphotericin B/pharmacologyABSTRACT
In this study, a new innovative hybrid membrane/vacuum swing adsorption (VSA) process is developed, modeled, and optimized for removal of CO2 from flue gases. The process benefits from the advantages of membrane simplicity and the high product quality of the adsorption system. The main advantage of this new process is the simultaneous increases of both CO2 purity and its recovery. To achieve this objective, in the first step, a membrane system using PEBAX nano-composite membrane was modeled. In the second step, a VSA system using zeolite 13X was modeled. The adsorption equilibrium was predicted by the Toth isotherm. To increase the modeling accuracy, the mass transfer rate was calculated based on the quasi-second-order model. At the final step, the hybrid membrane/VSA process was modeled. Comparison of the new hybrid membrane/VSA with the stand-alone VSA process shows that the CO2 product concentration was increased by 39% and the recovery was improved by 8%. To study the process limitations and increase the product quality, a sensitivity analysis was performed on vacuum pressure, membrane stage cut, and recycle ratio. Based on the results, decreasing the membrane stage cut to 15% and applying a recycle ratio equal to 2 will increase the product quality with the cost of increasing the equipment size. Finally, to achieve the required purity and recovery specification in industrial applications, the process was optimized using the genetic algorithm. Based on these results, it is possible to produce CO2 with 94.7% purity and 99% recovery and N2 with 99.9% purity and 97.3% recovery by regenerating the adsorbents at 0.01 bar, setting the membrane stage cut equal to 11%, keeping the recycle ratio at 1.89, and adjusting the purge-to-feed ratio to 2%.
Subject(s)
Carbon DioxideABSTRACT
In this research, waste tyre rubber was used for activated carbon production with a novel route by modified physo-chemical approach. Potassium hydroxide and carbon dioxide were selected as chemical and physical activating agents, respectively and the process was carried out without carbonization under inert atmospheric conditions. The experiments were designed by applying the central composite design (CCD) as one of the subsets of response surface methodology (RSM). The effects of activation temperature (550-750 °C), activation time (15-75 min), impregnation ratio of KOH/rubber (0.75-3.75) and CO2 flow rate (200-400 mL/min) on production yield and specific surface area of produced activated carbon were studied. Based on the results, the 2FI and quadratic models were selected for production yield and specific surface area, respectively. The activation temperature was the main effective parameter on both responses in this process. The production yield and specific surface area of produced activated carbon at optimized conditions for each model were 47% and 928 m2/g, respectively. BET, XRF, XRD, FT-IR, EDS and FE-SEM analyses were carried out on the optimized sample of specific surface area model in order to investigate the residual salts and morphological porous structures. Based on the surface properties and the presence of sulfur compounds in produced activated carbon, this activated carbon has the ability of eliminating heavy metals such as mercury from industrial waste water.
