The bovine milk allergenic protein, 'β-lactoglobulin' is one of the leading causes of milk allergic reaction. In this research, a novel label-free non-faradaic capacitive aptasensor was designed to detect β-lactoglobulin using a Laser Scribed Graphene (LSG) electrode. The graphene was directly engraved into a microgapped (~ 95 µm) capacitor-electrode pattern on a flexible polyimide (PI) film via a simple one-step CO2 laser irradiation. The novel hybrid nanoflower (NF) was synthesized using 1,1'-carbonyldiimidazole (CDI) as the organic molecule and copper (Cu) as the inorganic molecule via one-pot biomineralization by tuning the reaction time and concentration. NF was fixed on the pre-modified PI film at the triangular junction of the LSG microgap specifically for bio-capturing β-lactoglobulin. The fine-tuned CDI-Cu NF revealed the flower-like structures was viewed through field emission scanning electron microscopy. Fourier-transform infrared spectroscopy showed the interactions with PI film, CDI-Cu NF, oligoaptamer and β-lactoglobulin. The non-faradaic sensing of milk allergen β-lactoglobulin corresponds to a higher loading of oligoaptamer on 3D-structured CDI-Cu NF, with a linear range detection from 1 ag/ml to 100 fg/ml and attomolar (1 ag/ml) detection limit (S/N = 3:1). This novel CDI-Cu NF/LSG microgap aptasensor has a great potential for the detection of milk allergen with high-specificity and sensitivity.
Graphene (GR) and its derivatives are promising materials on the horizon of nanotechnology and material science and have attracted a tremendous amount of research interest in recent years. The unique atom-thick 2D structure with sp(2) hybridization and large specific surface area, high thermal conductivity, superior electron mobility, and chemical stability have made GR and its derivatives extremely attractive components for composite materials for solar energy conversion, energy storage, environmental purification, and biosensor applications. This review gives a brief introduction of GR's unique structure, band structure engineering, physical and chemical properties, and recent energy-related progress of GR-based materials in the fields of energy conversion (e.g., photocatalysis, photoelectrochemical water splitting, CO2 reduction, dye-sensitized and organic solar cells, and photosensitizers in photovoltaic devices) and energy storage (batteries, fuel cells, and supercapacitors). The vast coverage of advancements in environmental applications of GR-based materials for photocatalytic degradation of organic pollutants, gas sensing, and removal of heavy-metal ions is presented. Additionally, the use of graphene composites in the biosensing field is discussed. We conclude the review with remarks on the challenges, prospects, and further development of GR-based materials in the exciting fields of energy, environment, and bioscience.
In the present investigation, the operating efficiency of a bench-top air-driven microfluidizer has been compared to that of a bench-top high power ultrasound horn in the production of pharmaceutical grade nanoemulsions using aspirin as a model drug. The influence of important process variables as well as the pre-homogenization and drug loading on the resultant mean droplet diameter and size distribution of emulsion droplets was studied in an oil-in-water nanoemulsion incorporated with a model drug aspirin. Results obtained show that both the emulsification methods were capable of producing very fine nanoemulsions containing aspirin with the minimum droplet size ranging from 150 to 170 nm. In case of using the microfluidizer, it has been observed that the size of the emulsion droplets obtained was almost independent of the applied microfluidization pressure (200-600 bar) and the number of passes (up to 10 passes) while the pre-homogenization and drug loading had a marginal effect in increasing the droplet size. Whereas, in the case of ultrasound emulsification, the droplet size was generally decreased with an increase in sonication amplitude (50-70%) and period of sonication but the resultant emulsion was found to be dependent on the pre-homogenization and drug loading. The STEM microscopic observations illustrated that the optimized formulations obtained using ultrasound cavitation technique are comparable to microfluidized emulsions. These comparative results demonstrated that ultrasound cavitation is a relatively energy-efficient yet promising method of pharmaceutical nanoemulsions as compared to microfluidizer although the means used to generate the nanoemulsions are different.
This study is the first to demonstrate dimensional optimization of nanowire-complementary metal-oxide-semiconductor inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on both dimensions ratio and digital voltage level (Vdd). Diameter optimization reveals that when Vdd increases, the optimized value of (Dp/Dn) decreases. Channel length optimization results show that when Vdd increases, the optimized value of Ln decreases and that of (Lp/Ln) increases. Dimension ratio optimization reveals that when Vdd increases, the optimized value of Kp/Kn decreases, and silicon nanowire transistor with suitable dimensions (higher Dp and Ln with lower Lp and Dn) can be fabricated.
Nanomedicine and nano delivery systems are a relatively new but rapidly developing science where materials in the nanoscale range are employed to serve as means of diagnostic tools or to deliver therapeutic agents to specific targeted sites in a controlled manner. Nanotechnology offers multiple benefits in treating chronic human diseases by site-specific, and target-oriented delivery of precise medicines. Recently, there are a number of outstanding applications of the nanomedicine (chemotherapeutic agents, biological agents, immunotherapeutic agents etc.) in the treatment of various diseases. The current review, presents an updated summary of recent advances in the field of nanomedicines and nano based drug delivery systems through comprehensive scrutiny of the discovery and application of nanomaterials in improving both the efficacy of novel and old drugs (e.g., natural products) and selective diagnosis through disease marker molecules. The opportunities and challenges of nanomedicines in drug delivery from synthetic/natural sources to their clinical applications are also discussed. In addition, we have included information regarding the trends and perspectives in nanomedicine area.
Palm kernel oil esters nanoemulsion-loaded with chloramphenicol was optimized using response surface methodology (RSM), a multivariate statistical technique. Effect of independent variables (oil amount, lecithin amount and glycerol amount) toward response variables (particle size, polydispersity index, zeta potential and osmolality) were studied using central composite design (CCD). RSM analysis showed that the experimental data could be fitted into a second-order polynomial model. Chloramphenicol-loaded nanoemulsion was formulated by using high pressure homogenizer. The optimized chloramphenicol-loaded nanoemulsion response values for particle size, PDI, zeta potential and osmolality were 95.33nm, 0.238, -36.91mV, and 200mOsm/kg, respectively. The actual values of the formulated nanoemulsion were in good agreement with the predicted values obtained from RSM. The results showed that the optimized compositions have the potential to be used as a parenteral emulsion to cross blood-brain barrier (BBB) for meningitis treatment.
The utilization of natural mica as a biocatalyst support in kinetic investigations is first described in this study. The formation of lactose caprate from lactose sugar and capric acid, using free lipase (free-CRL) and lipase immobilized on nanoporous mica (NER-CRL) as a biocatalyst, was evaluated through a kinetic study. The apparent kinetic parameters, K(m) and V(max), were determined by means of the Michaelis-Menten kinetic model. The Ping-Pong Bi-Bi mechanism with single substrate inhibition was adopted as it best explains the experimental findings. The kinetic results show lower K(m) values with NER-CRL than with free-CRL, indicating the higher affinity of NER-CRL towards both substrates at the maximum reaction velocity (V(max,app)>V(max)). The kinetic parameters deduced from this model were used to simulate reaction rate data which were in close agreement with the experimental values.
Highly photocatalytically active copper chromite nanostructured material were prepared via a novel simple hydrothermal reaction between [Cu(en)2(H2O)2]Cl2 and [Cr(en)3]Cl3.3H2O at low temperature, without adding any pH regulator or external capping agent. The as-synthesized nanostructured copper chromite was analyzed by transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy, energy dispersive X-ray microanalysis (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. Results of the morphological investigation of the as-synthesized products illustrate that the shape and size of the copper chromite depended on the surfactant sort, reaction duration and temperature. Moreover, the photocatalytic behavior of as-obtained copper chromite was evaluated by photodegradation of acid blue 92 (anionic dye) as water pollutant.
Deoxynivalenol (DON), a cosmopolitan mycotoxin found in agricultural commodities causes serious health maladies to human and animals when accidently consumed even at a low quantity. It necessitates selective and sensitive devices to analyse DON as the conventional methods are complex and time-consuming. This study is focused on developing a selective biosensing system using iron nanoflorets graphene nickel (INFGN) as the transducer and a specific aptamer as the biorecognition element. 3D-graphene is incorporated using a low-pressure chemical vapour deposition followed by the decoration of iron nanoflorets using electrochemical deposition. INFGN enables a feasible bio-capturing due to its large surface area. The X-ray photoelectron spectroscopy analysis confirms the presence of the hydroxyl groups on the INFGN surface, which acts as the linker. Clear Fourier-transform infrared peak shifts affirm the changes with surface chemical modification and biomolecular assembly. The limit of detection attained is 2.11 pg mL-1 and displays high stability whereby it retains 30.65% of activity after 48 h. The designed INFGN demonstrates remarkable discrimination of DON against similar mycotoxins (zearalenone and ochratoxin A). Overall, the high-performance biosensor shown here is an excellent, simple and cost-effective alternative for detecting DON in food and feed samples.
Rationally designed biosensing system supports multiplex analyses is warranted for medical diagnosis to determine the level of analyte interaction. The chemically functionalized novel multi-electrode polysilicon nanogap (PSNG) lab-on-chip is designed in this study, facilitates multiplex analyses for a single analyte. On the fabricated 69nm PSNG, biocompatibility and structural characteristics were verified for the efficient binding of Human Chorionic Gonadotropin (hCG). With the assistance of microfluidics, hCG sample was delivered via single-injection to 3-Aminopropyl(triethoxy)silane (APTES) and Glycidoxypropyl(trimethoxy)silane (GPMS) modified PSNG electrodes and the transduced signal was used to investigate the dielectric mechanisms for multiplex analyses. The results from amperometric response and impedance measurement delivered the scale of interaction between anti-hCG antibody and hCG that exhibited 6.5 times higher sensitivity for the chemical linker, APTES than GPMS. Under optimized experimental conditions, APTES and GPMS modified immunosensor has a limit of detection as 0.56mIU/ml and 2.93mIU/ml (at S/N=3), with dissociation constants (Kd) of 5.65±2.5mIU/ml and 7.28±2.6mIU/ml, respectively. These results suggest that multiplex analysis of single target could enhance the accuracy of detection and reliable for real-time comparative analyses. The designed PSNG is simple, feasible, requires low sample consumption and could be applied for any given multiplex analyses.
A new approach to design multifunctional chitosan based nanohydrogel with enhanced glucose sensitivity, stability, drug loading and release profile are reported. Two approaches were followed for functionalization of chitosan based nanohydrogel with 3-APBA via EDC and 3-APTES. The effective functionalization, structure and morphology of Chitosan based IPN respectively were confirmed by FTIR, SEM and AFM. At physiological conditions, the glucose-induced volume phase transition and release profile of the model drug Alizarin Red with 1,2-diol structure (comparative to insulin as a drug as well as a dye for bio separation) were studied at various glucose concentrations, pH and ionic strengths. The results suggested a new concept for diabetes treatment and diols sensitivity in view of their potential hi-tech applications in self-regulated on-off response to the treatment (drug delivery and bio separation concurrently).
Tamoxifen (TAM) has been used in the treatment of breast cancers and is supplemented with erythropoietin (EPO) to alleviate the cancer-related anemia. The purported deleterious effects caused by the use of EPO with chemotherapeutic agents in the treatment of cancer-related anemia vary across studies and remain controversial. The use of nanoparticles as a drug delivery system has the potential to improve the specificity of anticancer drugs. In this study, we simultaneously incorporated two pharmacological active ingredients in one nanocarrier to develop EPO-conjugated TAM-loaded lipid nanoparticles (EPO-TAMNLC), a targeted delivery system, to enhance the cytotoxic activity while reducing the side effects of the ingredients. The effect of temperature in modulating the thermodynamic parameters associated with the binding of EPO and TAMNLC was assessed using isothermal titration calorimetry, while the unfolding of EPO structure was determined using fluorescence-quenching approach. The association efficiency of EPO and TAMNLC was 55.43%. Unlike binding of albumin to TAMNLC, the binding of EPO to TAMNLC occurred through endothermic and entropy-driven reaction. The EPO-TAMNLC formulation was stable because of the hydrophobic interaction and the high free energy, suggesting the spontaneity of the interactions between EPO and TAMNLC. The EPO-TAMNLC enhanced the in vitro cytotoxicity of TAM to MCF-7 cells. The EPO surface-functionalized TAMNLC could sequentially deliver EPO and TAM as well as improving site-specific delivery of these therapeutic compounds.
The study reports on the preparation of cellulose nanocrystals (CNCs) from wastepaper, as an environmental friendly approach of source material, which can be a high availability and low-cost precursor for cellulose nanomaterial processing. Alkali and bleaching treatments were employed for the extraction of cellulose particles followed by controlled-conditions of acid hydrolysis for the isolation of CNCs. Attenuated total reflectance Fourier Transform Infrared (ATR FTIR) spectroscopy was used to analyze the cellulose particles extracted while Transmission electron microscopy images confirmed the presence of CNCs. The diameters of CNCs are in the range of 3-10nm with a length of 100-300nm while a crystallinity index of 75.9% was determined from X-ray diffraction analysis. The synthesis of this high aspect ratio of CNCs paves the way toward alternative reuse of wastepaper in the production of CNCs.
The unique programmability of nucleic acids offers alternative in constructing excitable and functional nanostructures. This work introduces an autonomous protocol to construct DNA Tetris shapes (L-Shape, B-Shape, T-Shape and I-Shape) using modular DNA blocks. The protocol exploits the rich number of sequence combinations available from the nucleic acid alphabets, thus allowing for diversity to be applied in designing various DNA nanostructures. Instead of a deterministic set of sequences corresponding to a particular design, the protocol promotes a large pool of DNA shapes that can assemble to conform to any desired structures. By utilising evolutionary programming in the design stage, DNA blocks are subjected to processes such as sequence insertion, deletion and base shifting in order to enrich the diversity of the resulting shapes based on a set of cascading filters. The optimisation algorithm allows mutation to be exerted indefinitely on the candidate sequences until these sequences complied with all the four fitness criteria. Generated candidates from the protocol are in agreement with the filter cascades and thermodynamic simulation. Further validation using gel electrophoresis indicated the formation of the designed shapes. Thus, supporting the plausibility of constructing DNA nanostructures in a more hierarchical, modular, and interchangeable manner.
Hydrothermal method has been proven to be an effective method to synthesise the nanostructured titanium dioxide (TiO2) with good morphology and uniform distribution at low temperature. Despite of employing a well-known and commonly used glass substrate as the support to hydrothermally synthesise the nanostructured TiO2, this study emphasised on the application of kaolin hollow fibre membrane as the support for the fabrication of kaolin/TiO2 nanorods (TNR) membrane. By varying the hydrothermal reaction times (2 h, 6 h, and 10 h), the different morphology, distribution, and properties of TiO2 nanorods on kaolin support were observed by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscope (AFM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). It was found that the well-dispersed of TiO2 nanorods have improved the surface affinity of kaolin/TNR membrane towards water, allowing kaolin/TNR membrane prepared from 10 h of hydrothermal reaction to exhibit the highest water permeation of 165 L/h.m2.bar. In addition, this prepared membrane also showed the highest photocatalytic activity of 80.3% in the decolourisation of reactive black 5 (RB5) under UV irradiation. On top of that, the kaolin/TNR membrane prepared from 10 h of hydrothermal reaction also exhibited a good resistance towards photocorrosion, enabling the reuse of this membrane for three consecutive cycles of photocatalytic degradation of RB5 without showing significant reduction in photocatalytic efficiency towards the decolourisation of RB5.
The pragmatic outcome of a lung cancer diagnosis is closely interrelated in reducing the number of fatal death caused by the world's top cancerous disease. Regardless of the advancement made in understanding lung tumor, and its multimodal treatment, in general the percentage of survival remain low. Late diagnosis of a cancerous cell in patients is the major hurdle for the above circumstances. In the new era of a lung cancer diagnosis with low cost, portable and non-invasive clinical sampling, nanotechnology is at its inflection point where current researches focus on the implementation of biosensor conjugated nanomaterials for the generation of the ideal sensing. The present review encloses the superiority of nanomaterials from zero to three-dimensional nanostructures in its discrete and nanocomposites nanotopography on sensing lung cancer biomarkers. Recent researches conducted on definitive nanomaterials and nanocomposites at multiple dimension with distinctive physiochemical property were focused to subside the cases associated with lung cancer through the development of novel biosensors. The hurdles encountered in the recent research and future preference with prognostic clinical lung cancer diagnosis using multidimensional nanomaterials and its composites are presented.
Nanocellulose was successfully isolated from Gelidium elegans red algae marine biomass. The red algae fiber was treated in three stages namely alkalization, bleaching treatment and acid hydrolysis treatment. Morphological analysis was performed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). TEM results revealed that the isolated nanocellulose had the average diameter and length of 21.8±11.1nm and of 547.3±23.7nm, respectively. Fourier transform infrared (FTIR) spectroscopy proved that the non-cellulosic polysaccharides components were progressively removed during the chemically treatment, and the final derived materials composed of cellulose parent molecular structure. X-ray diffraction (XRD) study showed that the crystallinity of yielded product had been improved after each successive treatments subjected to the treated fiber. The prepared nano-dimensional cellulose demonstrated a network-like structure with higher crystallinity (73%) than that of untreated fiber (33%), and possessed of good thermal stability which is suitable for nanocomposite material.
Recent bioinspired efforts of designing novel nanoenzyme-based electrocatalysts are driven by the urgency of making bioelectrofuels more affordable and efficient. Unlike natural enzymes, nanoenzyme-modified electrodes with large surface areas enclose numerous biomimicking active sites to facilitate enhanced microbial growth followed by increased reactant-to-bioelectrofuel conversion.
O/W nanoemulsions are isotropic colloidal systems constituted of oil droplets dispersed in continuous aqueous media and stabilised by surfactant molecules. Nanoemulsions hold applications in more widespread technological domains, more crucially in the pharmaceutical industry. Innovative nanoemulsion-based drug delivery system has been suggested as a powerful alternative strategy through the useful means of encapsulating, protecting, and delivering the poorly water-soluble bioactive components. Consequently, there is a need to generate an emulsion with small and consistent droplets. Diverse studies acknowledged that ultrasonic cavitation is a feasible and energy-efficient method in making pharmaceutical-grade nanoemulsions. This method offers more notable improvements in terms of stability with a lower Ostwald ripening rate. Meanwhile, a microstructured reactor, for instance, microchannel, has further been realised as an innovative technology that facilitates combinatorial approaches with the acceleration of reaction, analysis, and measurement. The recent breakthrough that has been achieved is the controlled generation of fine and monodispersed multiple emulsions through microstructured reactors. The small inner dimensions of microchannel display properties such as short diffusion paths and high specific interfacial areas, which increase the mass and heat transfer rates. Hence, the combination of ultrasonic cavitation with microstructures (microchannel) provides process intensification of creating a smaller monodispersed nanoemulsion system. This investigation is vital as it will then facilitate the creation of new nanoemulsion based drug delivery system continuously. Following this, the fabrication of microchannel and setup of its combination with ultrasound was conducted in the generation of O/W nanoemulsion, as well as optimisation to analyse the effect of varied operating parameters on the mean droplet diameter and dispersity of the nanoemulsion generated, besides monitoring the stability of the nanoemulsion. Scanning transmission electron microscopy (STEM) images were also carried out for the droplet size measurements. In short, the outcomes of this study are encouraging, which necessitates further investigations to be carried out to advance a better understanding of coupling microchannel with ultrasound to produce pharmaceutical-grade nanoemulsions.
While bulk zinc oxide (ZnO) is of non-toxic in nature, ZnO nanoarchitectures could potentially induce the macroscopic characteristics of oxidative, lethality and toxicity in the water environment. Here we report a systematic study through state-of-the-art controllable synthesis of multi-dimensional ZnO nanoarchitectures (i.e. 0D-nanoparticle, 1D-nanorod, 2D-nanosheet, and 3D-nanoflowers), and subsequent in-depth understanding on the fundamental factor that determines their photoactivities. The photoactivities of resultant ZnO nanoarchitectures were interpreted in terms of the photodegradation of salicylic acid as well as inactivation of Bacillus subtilis and Escherichia coli under UV-A irradiation. Photodegradation results showed that 1D-ZnO nanorods demonstrated the highest salicylic acid photodegradation efficiency (99.4%) with a rate constant of 0.0364 min-1. 1D-ZnO nanorods also exhibited the highest log reductions of B. subtilis and E. coli of 3.5 and 4.2, respectively. Through physicochemical properties standardisation, an intermittent higher k value for pore diameter (0.00097 min-1 per mm), the highest k values for crystallite size (0.00171 min-1 per nm) and specific surface area (0.00339 min-1 per m2/g) contributed to the exceptional photodegradation performance of nanorods. Whereas, the average normalised log reduction against the physicochemical properties of nanorods (i.e. low crystallite size, high specific surface area and pore diameter) caused the strongest bactericidal effect.