A novel pH-sensitive drug release system has been synthesised by functional mesoporous silica materials. SBA-15, calcium modified SBA-15 (Ca-SBA-15) and phosphate modified SBA-15 (PO₄-SBA-15) were synthesised using solvent evaporation method. It is a simple and feasible way to prepare the doping mesoporous silica materials. They show the large surface are, high pore volume and uniform pore size. Metformin hydrochloride was used as the model drug, and the control release behaviour was investigated. The functional mesoporous silica materials show the pH sensitive drug release behaviour because of the adjustable interaction between the drug molecule and the host.

Cobalt ferrite nanoparticles with average sizes of 14, 9 and 6 nm were synthesised by the chemical co-precipitation technique. Average particle sizes were varied by changing the chitosan surfactant to precursor molar ratio in the reaction mixture. Transmission electron microscopy images revealed a faceted and irregular morphology for the as-synthesised nanoparticles. Magnetic measurements revealed a ferromagnetic nature for the 14 and 9 nm particles and a superparamagnetic nature for the 6 nm particles. An increase in saturation magnetisation with increasing particle size was noted. Relaxivity measurements were carried out to determine T ₂ value as a function of particle size using nuclear magnetic resonance measurements. The relaxivity coefficient increased with decrease in particle size and decrease in the saturation magnetisation value. The observed trend in the change of relaxivity value with particle size was attributed to the faceted nature of as-synthesised nanoparticles. Faceted morphology results in the creation of high gradient of magnetic field in the regions adjacent to the facet edges increasing the relaxivity value. The effect of edges in increasing the relaxivity value increases with decrease in the particle size because of an increase in the total number of edges per particle dispersion.

Preparation of protective coating possessing antimicrobial properties is present day need as they increase the shelf life of fruits and vegetables. In the present study, preparation of agar-silver nanoparticle film for increasing the shelf life of fruits is reported. Silver nanoparticles (Ag-NPs) biosynthesised using an extract of Ocimum sanctum leaves, were mixed with agar–agar to prepare an agar-silver nanoparticles (A-AgNp) film. This film was surface-coated over the fruits, Citrus aurantifolium (Thornless lime) and Pyrus malus (Apple), and evaluated for the determination of antimicrobial activity of A-AgNp films using disc diffusion method, weight loss and shelf life of fruits. This study demonstrates that these A-AgNp films possess antimicrobial activity and also increase the shelf life of fruits.

In this report, a highly sensitive electrochemical biosensor based on cobaltferritin immobilised on a self-assembled monolayer modified gold electrode for determination of hydrogen peroxide (H₂O₂) in phosphate buffer solution (pH 7.5) was investigated. The modified electrode showed excellent electrochemical activity for oxidation of H₂O₂. The response to H₂O₂ on the modified electrode was examined using linear sweep and differential pulse voltammetries. In phosphate buffer (pH 7.5, 0.1 M), the fabricated biosensor exhibited a linear dependence (R = 0.989) on the concentration of H₂O₂ from 2.49 × 10⁻⁹ to 1.91 × 10⁻⁸ M, a high sensitivity of −0.4099 µA/nM and detection limit of 2.48 × 10⁻⁹ based on a signal-to-noise ratio of 3. Charge transfer coefficient (α) and the exchange current (i ₀) of oxidation for H₂O₂ were found to be 0.57 and 7.55 A, respectively. It has been shown that, this modified electrode is able to determine H₂O₂ with a high sensitivity, low detection limit and high selectivity.

The present study focused on the development of an effective oral vaccine delivery system of poly(vinyl alcohol)-coated chitosan microparticles-based recombinant hepatitis B vaccine. Chitosan microparticles were prepared by ionotropic gelation technique; they were loaded with recombinant hepatitis B vaccine and coated with poly(vinyl alcohol). The average sizes of the microparticles were measured in the range of 100–410 nm. The optimal loading capacity and loading efficiency were recorded around 3.4 and 74%, respectively. In vitro release study shows that the prepared microparticles release the antigen in a sustained manner. Moreover, the microparticles were resistant to simulated gastric environment and release the antigen in the targeted intestinal milieu. Furthermore, oral immunisation of rats with poly(vinyl alcohol)-coated chitosan hepatitis-B microparticles vaccine shows comparable seroprotective immune response to presently practiced intramuscular vaccination. The results demonstrated that poly(vinyl alcohol)-coated chitosan microparticles have the potential for being used as an oral vaccine delivery system for hepatitis B vaccine and may be a suitable alternative for needle-based vaccination.

Biochemically sensitive field-effect sensors are fabricated with simplified chip technology. Its fabrication process flow is designed based on metal gate complementary metal-oxide semiconductor technology, in which only six pattern masks are employed. The sensors are measured as field modulation resistors since they are made in its depletion mode. The milliampere magnitude response of conducting currents from certain biochemical materials achieves distinct sensitivity when measured on our fabricated sensors with different sensitive areas of W/L = 4.2 and 20.0. To check the stability of the sensor, up to 20 repeated tests are conducted on the same sensor chip operated in its three states, in which no materials (blank state, called ‘blank’), pure water and biochemical materials are coated on its gate dielectric film, respectively. Measured results show that the response currents for certain materials are distributed in certain current range. Taking the response current of blank as a reference value, the response current of pure water is positive but very close to that of blank because of the small electric dipole properties of pure water. However, the response current of biochemical materials are negative and far apart from that of blank, because the biochemical materials have large electric dipole properties and clearly show measurement resolution.

A novel hierarchical porous bioactive glasses were synthesised with cattail stem and triblock polyethylene oxide–propylene oxide block copolymer (P123) as macroporous template and mesoporous template, respectively. The structural and textural properties of materials were characterised by X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, nitrogen adsorption–desorption, energy dispersive spectrometer and vibrating sample magnetometer technique. The results reveal the bioglasses possess multilevel porous structure with the macroporous size about 50 μm and the mesopore with the diameter of 3.86 nm. Furthermore, metformin HCl was used as the model drug. The drug release kinetics and hydroxyapatite (HAP, (Ca₁₀(PO₄)₆(OH)₂)) inducing-growth ability of the composites were studied, respectively. The system exhibits the fast HAP inducing-growth ability and long-term drug delivery, making them a good candidate for bone tissue regeneration.

Brosimum gaudichaudii Tréc. (Moraceae) is a common Brazilian Cerrado plant known by its pharmaceutical industry relevance. The authors investigated the latex protein components and potential biotechnological applications. Some protein fragments had their sequences elucidated, presenting similarities to jacalin and Kunitz-type trypsin inhibitors. Amino acid residue modifications were found, such as glutamine N-terminal residue cyclisation into pyroglutamic acid residue, and mass differences corresponding to hexoses and N-acetylhexosamine presence. The latex was used to produce a nanoscale structured film, which presented an increased attraction and reduced adhesion behaviours. The film presented high homogeneity, as observed by low nanoroughness values, probably because of its intrinsic components, such as the jacalin-like protein that has known agglutination properties. The immobilised Kunitz-type trypsin inhibitor presence in the latex film allow us to point out to applications related to this inhibition, as in active food packaging, since these peptidase inhibitors are able to inhibit pests and microorganism proliferation.

Nanotechnologies reinvented the utilities of various substances in healthcare. Copper in its native form (copper ion) has been well studied for its antimicrobial and anti-inflammatory activities. Copper in its nano form could have better biological profile and finds many applications in healthcare. There were reports on synthesis of copper nanoparticles by physical and chemical methods and their biological activities, although these methods have limitations. Biosynthesis of nanoparticles using microbes is an ecofriendly approach helping in the synthesis of biocompatible and stable nanoparticles. With this background in mind, the present study was designed to synthesise copper nanoparticles by Pseudomonas aeruginosa and testing their efficacy in enhancing the pace of wound healing. Culture supernatant was used to synthesise copper nanoparticles. Optimum conditions were selected to maximise the biosynthesis of nanoparticles. Biosynthesised copper nanoparticles (BNCPs) were characterised by Malvern zeta sizer and scanning electron microscopy. Average particle size, polydispersivity index and zeta potential of BNCPs were found to be 110.9 nm, 0.312 and (−) 18.3 mV, respectively. BNCPs was evaluated for its wound healing activity by excision wound model in rat. The pace of wound healing was enhanced by BNCPs compared with copper in native form.

Specific primers play an important role in polymerase chain reaction (PCR) experiments, and therefore it is essential to find specific primers of outstanding quality. Unfortunately, many PCR constraints must be simultaneously inspected which makes specific primer selection difficult and time-consuming. This paper introduces a novel computational intelligence-based method, Teaching-Learning-Based Optimisation, to select the specific and feasible primers. The specified PCR product lengths of 150–300 bp and 500–800 bp with three melting temperature formulae of Wallace's formula, Bolton and McCarthy's formula and SantaLucia's formula were performed. The authors calculate optimal frequency to estimate the quality of primer selection based on a total of 500 runs for 50 random nucleotide sequences of ‘Homo species’ retrieved from the National Center for Biotechnology Information. The method was then fairly compared with the genetic algorithm (GA) and memetic algorithm (MA) for primer selection in the literature. The results show that the method easily found suitable primers corresponding with the setting primer constraints and had preferable performance than the GA and the MA. Furthermore, the method was also compared with the common method Primer3 according to their method type, primers presentation, parameters setting, speed and memory usage. In conclusion, it is an interesting primer selection method and a valuable tool for automatic high-throughput analysis. In the future, the usage of the primers in the wet lab needs to be validated carefully to increase the reliability of the method.

Novel generation of analytical technology based on nanopores has provided possibilities to fabricate nanofluidic devices for low-cost DNA sequencing or rapid biosensing. In this paper, a simplified model was suggested to describe DNA molecule's translocation through a nanopore, and the internal potential, ion concentration, ionic flowing speed and ionic current in nanopores with different sizes were theoretically calculated and discussed on the basis of Poisson–Boltzmann equation, Navier–Stokes equation and Nernst–Planck equation by considering several important parameters, such as the applied voltage, the thickness and the electric potential distributions in nanopores. In this way, the basic ionic currents, the modulated ionic currents and the current drops induced by translocation were obtained, and the size effects of the nanopores were carefully compared and discussed based on the calculated results and experimental data, which indicated that nanopores with a size of 10 nm or so are more advantageous to achieve high quality ionic current signals in DNA sensing.

Nanoparticulate drug delivery systems are of considerable therapeutic interest for delivery of drugs across from the blood–brain barrier. In this study, the ability of sodium chloride (NaCl) and different percentages of a water-soluble form of natural vitamin E, on the formation of poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs), as a potential carrier for drug delivery, was investigated. According to the obtained results, by increasing the percentage of natural vitamin E, the average particle size decreased and the range of diameters came closer. After using 0.26 w/v % vitamin E, the average size of the PLGA particles became <100 nm. Moreover, the particles containing NaCl led to the formation of even smaller particles. In addition, no obvious cytotoxicity was observed at various natural vitamin E amounts in one and three days, and the modified PLGA NPs could be considered biocompatible since they showed a little decrease in cellular viability.

The capacity of Ag nanoparticles to destroy various micro-organisms makes it one of the most powerful antimicrobial agents, an attractive feature against antibiotic resistant bacteria. Here, a simple method to develop coating of colloidal silver on paper using a biological method is presented. The coated paper was studied by scanning electron microscopy, X-ray diffraction technique and atomic absorption spectroscopy. The antibacterial activity of the coated paper against Escherichia coli and Staphylococcus aureus was measured by agar diffusion method. This study shows the potential use of the coated paper as a food antimicrobial packing material for longer shelf life.

The present work was focused on isolating a bacterial strain of Pseudomonas sp. with the ability to synthesise AgNPs rapidly. A strain of Pseudomonas aeruginosa designated JO was found to be a potential candidate for rapid synthesis of AgNPs with a synthesis time of 4h in light, at room temperature which is a shorter time period noticed for the synthesis when compared to the previous reports Biosynthesis of AgNPs was achieved by addition of culture supernatant with aqueous silver nitrate solution (1 mM). The reaction mixture exhibits change in colour from green to brown with a peak at 420 nm corresponding to the plasmon absorbance of AgNPs by UV–vis spectroscopy. The nanoparticles were characterised by X-ray diffraction (XRD), energy-dispersive X-ray analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), Zetasizer and transmission electron microscopy (TEM). The XRD spectrum exhibited 2θ values corresponding to the silver nanocrystals. TEM and SEM micrographs revealed the extracellular formation of polydispersed elongated nanoparticles with an average size of 27.5 nm. Synthesised nanoparticles showed antibacterial property against both gram-positive and gram-negative microorganisms, but more effective towards gram-negative.

The magnetic and macro/mesoporous bioactive glasses scaffolds are synthesised successfully by the combination of coral and P123 as co-templates through an evaporation-induced self-assembly process. The prepared material can induce the precipitation of hydroxyapatite layers on their surface in SBF only within 12 h. At the same time, the material exhibited excellent super-paramagnetic and mechanical property. Furthermore, the biocompatible assessment confirmed that the obtained material presented the good biocompatibility and the enhanced adherence of HeLa cells. Herein, the novel materials are expected to have potential application for bone tissue engineering.

The use of silver nanoparticle on various substrates has been widespread because of its good antibacterial properties that directly depend on the stability of the silver nanoparticles in a colloidal suspension. In this study, the colloidal solutions of the silver nanoparticles were synthesised by a simple and safe method by using lecithin as a stabilising agent and their stability was examined at various temperatures. The effect of the lecithin concentrations on the stability of the synthesised silver nanoparticles was examined from 25 to 80°C at 5°C intervals, by recording the changes in the UV–vis absorption spectra, the hydrodynamic diameter and the light scattering intensity of the silver nanoparticles. In addition, the morphology of the synthesised silver nanoparticles was investigated with the low-voltage scanning electron microscopy and transmission electron microscopy. The results indicated that increasing temperature caused different changes in the size of the stabilised and the unstabilised silver nanoparticles. The size of the stabilised silver nanoparticles reduced from 38 to 36 nm during increasing temperature, which confirmed good stability.

In this study, we prepared amorphous and crystalline silica nanoparticles from rice hulls biomass using pyrolysis technique at different processing temperatures such as 923, 973, 1023, 1073, 1123 and 1173 K. X-ray fluorescence studies show that the purity of all the synthesised silica nanoparticles is in the range of 98–99.7%. X-ray diffraction studies reveal that amorphous silica nanoparticles are formed at 923–1023 K, whereas crystalline particles at 1073–1173 K. Morphology and microstructure of silica nanoparticles are studied by scanning electron and transmission electron microscopes. Silica nanoparticles obtained at different processing temperatures yield particle size in the range of 6–100 nm. Chemical composition and surface functionalities of the particles are examined by energy-dispersive X-ray diffraction and Fourier transform infrared spectroscopic studies. The developed method effectively uses rice hulls biomass as a green natural source in the synthesis of amorphous and crystalline silica nanoparticles with high-specific surface area. The optimised processing temperature (1023 K) enables amorphous silica nanoparticles to have high-specific surface area of 538 m²g⁻¹.

Amyloid β _25–35 (Aβ _25–35) peptide is a peculiar peptide for its rapid aggregation properties and high neurotoxicity in Alzheimer's disease. Here, the interactions between gold nanoparticles (GNPs) and Aβ _25–35 monomers, oligomers and fibrils are explored under different molar ratio, temperature and pH by ultraviolet–visible and circular dichroism spectra, thioflavin T fluorescence assay and transmission electron microscope. It is concluded that Aβ _25–35 can induce the aggregation of GNPs at certain concentration of Aβ _25–35 monomer or oligomer. But at higher concentration of Aβ _25–35, GNPs aggregates dissociate again. Furthermore, the aggregation rate increases at higher temperature or for lower pH. These results might provide the basis of a simple diagnostic tool for detecting Alzheimer's disease.