Modification of mesoporous silica nanoparticles for ibuprofen loading and release in drug delivery

Mesoporous silica nanoparticles (MSN) were synthesized by conventional method and microwave heating as drug delivery platform for the adsorption and release of ibuprofen, an anti-inflammatory drug. MSN was modified by 3- aminopropyltriethoxysilane (APTES) and aluminum (Al) metal. Modification with APTES was conducted via co-condensation (MSN-APTco) and post-grafting method (MSN-APTpost) of MSN. The percentages of adsorption of ibuprofen were 100%, 71% and 78%, while the releases were 50%, 100% and 38% for MSN, MSN-APTco and MSN-APTpost, respectively, which resulted from the difference in the surface functional group. 1%, 5% and 10% of aluminum (Al) were loaded onto MSN via the impregnation method. The adsorptions of ibuprofen were 35%, 58% and 79%, while the releases were 100%, 86% and 89% for 1%, 5% and 10% Al loaded MSN, respectively. The increase in Bronsted acidity upon loading of Al up to 10% strongly bound the drug, which caused the highest adsorption but the slowest release of ibuprofen. MSN was also synthesized with microwave power of 100W (MSNMW100), 300W (MSN-MW300) and 450W (MSN-MW450). MSN-MW450 exhibited the highest ibuprofen adsorption (100%), followed by MSN-MW300 (75%) and MSNMW100 (58%), while the percentages of release were 65%, 81% and 95%, respectively, depicting longer channel of MSN demonstrated higher adsorptivity toward ibuprofen, while simultaneously delayed the release process. From all the studies, the vital factors for ibuprofen delivery were found to be the surface functional group, acidity and also the mesoporous channel length. With these factors, MSN can be designed to fulfill the desired drug delivery system. In conclusion, MSN can be tailored to have suitable features for slow drug release which provide constant release over a defined period to avoid repetitive administration. In parallel, MSN also could be employed as a fast drug release system that provides initial burst of drug release to achieve rapid and maximum relief

Comparison of physical and chemical method for removing copper from non-metallic printed circuit board scrap

Printed circuit boards (PCBs) are the basic components of electrical and electronic devices. E-waste management is challenging to implement due to accompanying difficulties and danger. Valuable metals and copper (Cu) are primarily recycled through various methods in the treatment of waste PCB. A large number of non-metals materials in PCBs are disposed of through combustion or in landfill, resulting in secondary pollution and resource waste. To reduce the amount of waste non-metallic PCB (NMPCB) and the influences toward environment, recent studies focused on the usage of NMPCB as filler to replace raw material. NMPCB as filler seems to have a good interaction with the raw materials and thus can enhance the strength of the newly formed product. In our study, we focused on developing new NMPCB added with waste NMPCB. Commercial NMPCBs are often a flat laminated composite comprising non-conductive substrate materials. Hence, pre-treatment methods to remove metals, especially Cu, must be investigated. The present study attempted to remove the Cu layer on PCB by using chemical and physical methods. The untreated and Cu removed PCB residues were characterized using X-ray diffraction (XRD), scanning electron microscopy, and infrared spectroscopy (FTIR) for the determination of structural and functional groups and hydrophobicity test. XRD analysis indicated that the Cu in untreated PCB was successfully removed using physical and chemical methods

Multi-walled carbon nanotubes improve the physicochemical properties of mesostructured silica nanoparticles for efficient adsorption of methylene blue

Carbon nanotubes (CNTs) have attracted great attention in nanoscale science and technology due to their unique optical, electronic a nd mechanical properties 1 . Besides, mesostructured silica nanoparticles (MSN) have become effective adsorbents owe to its high surface area and pore size which is essential to adsorb wide range of organic pollutant 2-4 . Modification of CNT with MSN may enhance the dispersion properties and adsorption capacities from their singles. In this study, a series of carbon nanotubes–mesostructured silica nanoparticles (CNT–MSN) composites were prepared by a simple sol-gel method with 1, 3 and 5 wt.% loading of CNT. The composites then calcined to remove surfactants (Scheme 1). Their surface properties were characterized by XRD, N 2 physisorption, TEM and FTIR, while the adsorption performance of the CNT–MSN composites were evaluated on the adsorption of methylene blue (MB) under varying pH (2–11), adsorbent dosage (0.05–0.5 g L - 1 ), initial MB concentration (5–100 mg L -1 ) and temperature (303-323 K). The increasing CNT loading into MSN were found to improve the physicochemical properties of the material and led to an enhanced adsorptivity for MB. N 2 physisorption measurements revealed the developmen t of a bimodal pore structure that increased the pore size, pore volume and surface area. The best conditions were achieved at pH 8, 0.05 g L -1 CNT–MSN dosage, 100 mg L -1 MB concentration and 303 K. The maximum adsorption capacity re ached for 5 wt.% CNT- MSN was 524 mg g -1 . The equilibrium data were evaluated using the Langmuir and Freundlich isotherm models, with the Langmuir model affording the best fit to the adsorption data. The adsorption kinetics was best described by the pseudo-first order model. Thermodynamic studies showed that the adsorption process was spontaneous, exothermic and occur through physisorption mechanism. Therefore, CNT-MSN is believed to be a promising adsorbent for dye removal as well as removal of wide range wastewater

Polycaprolactone/chlorophyllin sodium copper salt nanofibrous mats prepared by electrospinning for soft tissue engineering

This study examined the process of synthesising biodegradable nanofibres made up of polycaprolactone (PCL) and chlorophyllin sodium copper (CSC) through electrospinning for scaffolding in tissue engineering. Scaffolds provide a platform for cell regeneration for repairing damaged human tissues or organs. However, the issue lies in developing scaffolding that will provide a favourable environment for cell attachment and proliferation. One way to address this concern is to add CSC, which has been widely used in biomaterial applications, to the nanofibres. The structure and morphology of the nanofibres in this research were determined by using a scanning electron microscope (SEM), and their chemical properties were tested by using Fourier-transform infrared spectroscopy (FTIR). Moreover, the diameter and adhesive force of the nanofibres were investigated by using an atomic force microscope (AFM). The SEM examination revealed that the PCL/CSC nanofibres lost their fibrous structure, and the FTIR results proved that the nanofibres synthesised by electrospinning still consisted of PCL and CSC. The AFM examination showed that the diameter and adhesive force of PCL/CSC nanofibres were less than those of PCL nanofibres. This outcome resulted from the CSC’s inability to generate fibres on its own. Furthermore, its noncrystalloid structure prevented it from providing inner enhancement for PCL nanofibres. Hence, further studies are needed to ensure that PCL/CSC nanofibres can be used as an innovative type of scaffolding to provide an appropriate environment for living cells

Synthesis of mesoporous silica nanoparticles by variation of microwave power for the ibuprofen drug delivery

Mesoporous silica nanoparticles (MSN), which combine both unique properties of nanomaterials and mesostructured substances, have arouse special attention in biomedical research field due to its great advantages in many aspects such as well biocompatible, unique properties of tunable pore size and structure, large surface areas and pore volumes, controllable morphology and modifiable surfaces1-2. The traditional synthesis method of mesoporous materials is the hydrothermal route, which uses a certain amount of surfactants, as well as acid or alkali to compose a mixed aqueous preparation. Although finely ordered mesoporous materials are obtained, the process is time and energy consuming3. It is known that microwave (MW) heating promotes nucleation and can reduce the synthesis time and particle size significantly in comparison with the conventional convection heating method3. For the synthesis of periodic mesoporous organosilica, it was reported that the synthesis time was reduced from 72 h to 36 h when the self-assembly process was performed under MW irradiation. The resulting materials also exhibited a high surface area, large pore volume and large pore diameters4. Within this context, the microwave was utilized to synthesize the MSN under 100 W, 300 W and 450 W heating powers. Ammonia was chosen as the catalyst and ethylene glycol as the co-solvent because of their polarity, which is higher than that of NaOH and methanol or ethanol which are commonly used to synthesize mesoporous silica. All MSNs was tested for adsorption and release of an anti-inflammatory and anti-cancer drug, ibuprofen. The characterization revealed that the MSN prepared under 450 W (MSN450) produced the most crystallized and prominent mesoporous structure compared to lower power applied (Figure 1). MSN450 exhibited the highest ibuprofen adsorption, followed by MSN300 and MSN100, confirming that more crystallized MSN demonstrated higher adsorptivity toward ibuprofen. For the release study, MSN450 showed the slowest release rate of ibuprofen, followed by MSN300 and MSN100. All MSNs was found to exhibit good activity for the ibuprofen adsorption and release

Green synthesis of spherical shaped silver nanoparticles using allium cepa leaves extract and its photocatalytic activity

Spherical silver nanoparticles (AgNPs) (5–15 nm) were synthesized by a simple electrochemical method at room temperature using Allium Cepa (AC) leaves extract. AC leaves extract that acts as a reducing and stabilizing agent is capable of producing AgNPs without any agglomeration. The phytochemical properties of the leaves extract including total phenolic content, total flavonoid content, and its active species were studied. The crystallinity, morphology, and functional characteristics of the AgNPs were analyzed using an X–ray diffractometer, a transmission electron microscope, and a Fourier–transform infrared spectrometer, respectively. The characterization results verified the contribution of phenolic acids and flavonoids in reduction of Ag+ to metallic AgNPs and also in stabilization of the AgNPs. The catalytic activity of the AgNPs was tested towards the photodegradation of 2,4–dichlorophenoxyacetic acid (2,4–D) herbicide, in which showing a remarkable degradation performance of 80%. The results provide strong evidence to support the potential use of AC leaves extract to act as green reducing and stabilizing agents as well as a green electrolyte to synthesize well–scattered spherical shaped AgNPs

Synthesis of dual type Fe species supported mesostructured silica nanoparticles: Synergistical effects in photocatalytic activity

Dual type Fe species (isomorphously substituted Fe species and a colloidal a-FeOOH (IS-FeOOH)) supported on mesostructured silica nanoparticles (IS-FeOOH/MSN) were prepared by a simple electrochemical method followed by impregnation. Characterization was conducted using X-ray diffraction, transmission electron microscopy, surface area analysis, Fourier-transform infrared spectroscopy, nuclear magnetic resonance, electron spin resonance, and X-ray photoelectron spectroscopy. The results suggested that silica removal occurred in the MSN framework to isomorphously substitute Fe cations while retaining the colloidal structure of IS-FeOOH. The catalytic activity of IS-FeOOH/MSN was tested on photo-Fenton-like degradation of 2-chlorophenol under fluorescent light irradiation. The performance of the catalyst was in the following order: 10 wt% IS-FeOOH/MSN > 15 wt% IS-FeOOH/MSN > 5 wt% IS-FeOOH/MSN > MSN, with removal percentages of 92.2, 79.3, 73.1, and 14.2%, respectively. The results suggest that a synergistic effect between the dual type of Fe species (Si-O-Fe and IS-FeOOH colloid) and MSN played important roles in enhancing the degradation. The results provide strong evidence to support the potential use of IS-FeOOH/MSN as a photo-Fenton-like nanocatalyst for organic pollutants treatment

Effect of iridium loading on HZSM-5 for isomerization of n-heptane

The effect of iridium loading on the properties and catalytic isomerization of n-heptane over Ir-HZSM-5 is studied. Ir-HZSM-5 was prepared by impregnation method and subjected to isomerization process in the presence of flowing hydrogen gas. XRD and BET studies show that the presence of iridium stabilizes the crystalline structure of HZSM-5, leading to more ordered framework structure and larger surface area. TGA and FTIR results substantiate that iridium species interacts with OH group on the surface of HZSM-5. Pyridine FT-IR study verifies the interaction between iridium and surface OH group slightly increased the Brönsted and Lewis acid sites without changing the lattice structure of HZSM-5. The presence of iridium and the increase of strong Lewis acid sites on HZSM-5 were found to bring an increase about 4.1, 33.2 and 11.8 in conversion, selectivity and yield of n-heptane isomerization, respectively