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The use of titanium dioxide (also known as titania) in solar cells, biomaterials, and photocatalytic processes has generated an ever-increasing amount of interest. Titania is widely used in a variety of applications because it is nanocrystalline, chemically stable, has a high refractive index, is mechanically hard, and transmits visible light well. In this work, titania nanoparticles were formed via sol–gel synthesis, wherein the effect of varying pH values such as 3, 5, 7, 9, and 11 has been investigated on the synthesized nanoparticles by studying their structural characteristics and analyzing their optical transmittance. Structural analysis of the synthesized TiO2 shows formation of the brookite phase at all pH values under as-synthesized conditions. Moreover, structural parameters including crystallite size, dislocation density, and unit cell volume were also calculated. Cell volume was calculated at various pH levels and measured between 255.7 and 257.2 Å3. Optical analysis shows a transmission increase with a pH increase, and maximum transmission has been observed above 80% for a pH value of 11.

Silver nanoparticles were synthesized using locally purchased honey and silver nitrate solution. This method provides a simplistic and straightforward approach to the formation of silver nanoparticles. The silver nanoparticles with varying amounts of silver nitrate solution were characterized using ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy. In addition, dynamic light scattering characterization was used to determine the average size and size distribution of silver nanoparticles. Experimental results revealed that varying the amount of silver nitrate solution can control the size and absorption spectra of silver nanoparticles. A large amount of silver nitrate solution will exhibit a peak in the higher wavelength. The shifting of the absorption peaks at 401, 406, 407, 408, and 409 nm are believed to be related to the wavelength of the surface plasmon resonance. Moreover, a larger amount of silver nitrate solution also results in an increasing size with 27.2, 57.9, and 63.4 nm as revealed in the size distribution via dynamic light scattering. This green synthesis method of silver nanoparticles will provide a cost-effective production as an alternative to commercial antibacterial agents.

Silver nanoparticles have been well known to possess efficient antibacterial properties. Many studies conducted on silver nanoparticles synthesized in different routes, from physical methods to chemical techniques to biological synthesis. In this study, the biological route was utilized using Psidium guajava leaves extract mixed with silver nitrate to synthesize silver nanoparticles. In addition, syntheses were done at varying temperatures to investigate its effect over antibacterial properties of the silver nanoparticles obtained. Results showed blueshifting of UV-Vis peaks suggesting decrease in particle size as synthesis temperature increases. FTIR also showed that the synthesized nanoparticles may have been capped by phenolic compounds from the biomolecules in guava leaves. Finally, antibacterial tests via Disc Diffusion Test suggested that the silver nanoparticles biologically synthesized at higher temperatures are more effective bactericides than those synthesized at lower temperatures as indicated by the measured zones of inhibition.

Innovative technologies enable businesses to stay competitive in marketplace while also increasing profits in manufacturing of nanocomposites for water treatment. Aforementioned driving factors resulted in adoption of a number of innovative technologies, and no other trend has had a greater impact in recent years than Industry 4.0. Industry 4.0 is a comprehensive term that encompasses data management, manufacturing competitiveness, manufacturing processes, and efficiency. The term “Industry 4.0” refers to a group of key enabler technologies, such as cyber physical models, Internet of Things (IoT), artificial intelligence (AI), and big data analytics, including embedded devices which are all significant components to the mechanized and digitized industrial environments. AI approaches have been used for water treatment processes as well as desalination in recent years for optimizing the process along with providing realistic answers to water scarcity and water pollution-related issues. AI applications have been used to predict and minimize water treatment process operational costs by lowering costs and optimizing chemical utilization. Several AI models are successful and accurate in predicting effectiveness of various adsorbents used in the removal process of a variety of contaminants from water. To identify the current level of research and future development prospects of smart manufacturing, this study uses a comprehensive literature review technique for manufacturing sustainability of nanocomposite fabrication for water treatment applications. The model provided will help to create a baseline for AI and hybrid models in the water treatment and wastewater management sectors, allowing for the increased performance and innovative growth. It will serve to provide the framework and give guidance for researchers interested in creating superior nanocomposites for waste and fresh water treatment and management using Industry 4.0. This study looks at a variety of AI approaches as well as how they may be used in water treatment, with an emphasis on pollutant adsorption. This assessment also identified certain obstacles and research gaps in the field of AI applications in water treatment processes.

A straightforward approach to recycle waste expanded polystyrene (EPS) foam to produce polystyrene (PS) microfibers using the improvised centrifugal spinning technique is demonstrated in this work. A typical benchtop centrifuge was improvised and used as a centrifugal spinning device. The obtained PS microfibers were characterized for their potential application for oil adsorption. Fourier transform infrared spectroscopy results revealed similarity on the transmission bands of EPS foam and PS microfibers suggesting the preservation of the EPS foam’s chemical composition after the centrifugal spinning process. Scanning electron microscopy displayed well-defined fibers with an average diameter of 3.14 ± 0.59 μm. At the same time, energy dispersive X-ray spectroscopy revealed the presence of carbon and oxygen as the primary components of the fibers. Contact angle (θCA) measurements showed the more enhanced hydrophobicity of the PS microfiber (θCA = 100.2 ± 1.3°) compared to the untreated EPS foam (θCA = 92.9 ± 3.5°). The PS microfiber also displayed better oleophilicity compared to EPS foam. Finally, the fabricated PS microfibers demonstrated promising potential for oil removal in water with a calculated sorption capacity value of about 15.5 g/g even at a very short contact time. The fabricated PS fiber from the waste EPS foam may provide valuable insights into the valorization of polymeric waste materials for environmental and other related applications.

The mass production and consumption of plastics have serious effects on the environment, human health, and livelihood. Hence, global efforts to reduce plastic generation must be realized. This study aimed to determine the prevalence of microplastics in mangrove sediments of Cabadbaran, Buenavista, and Nasipit in Butuan Bay, Philippines. Seventy-two (72) microplastic particles were extracted from mangrove sediments dominated by fibrous type (71%) and blue (35%) as the most common color. Attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy was used to assess the polymer type of microplastics. Results reveal a total of six polymer types including high-density polyethylene, low-density polyethylene, polyethylene terephthalate, ethylene-vinyl acetate, polyamide, and polypropylene, with the latter comprising 39% of samples, the highest among the extracted particles. Overall, Nasipit (71.1/kg) obtained the highest microplastic density followed by Buenavista (48.9/kg) and Cabadbaran (40.0/kg). These data will serve as a piece of baseline information in crafting important environmental policies to address plastic pollution issues in the area. Long-term studies are recommended to better understand, monitor, and prevent further microplastic pollution in Butuan Bay.

The utilization of vegetable oil in producing bio-based polyol, as an alternative replacement to petroleum-based polyol in making polyurethane (PU) foam has gained a lot of interest due to its finite supply and low production cost. In this study, bio-based polyol using coconut oil as raw material produced PU foam as thermal insulation material. The vegetable oil-based polyol was prepared using a two-step method, while PU foams were prepared by the free-rise method. In order to enhance the thermal properties of the produce PU foams, phase change material (PCM) was added to the PU foam formulation. FTIR spectra result showed peaks at 2920 cm-1 and 2850-1, which signifies the CH2 asymmetric stretching, indicating that n-octadecane was successfully incorporated into PU foams. Moreover, heat flow meter (HFM) and thermo-gravimetric analysis (TGA) show PU foam with 1% n-octadecane shows better thermal properties than other produced PU foams. Furthermore, the universal testing machine (UTM) result shows an enhancement in the mechanical properties of the produced PU foam. These results demonstrate that the addition of n-octadecane to the PU foam formulation improved the mechanical properties of PU foams while enhancing their thermal properties.

The pollution of aquatic systems by microplastics is a well-known environmental problem. However, limited studies have been conducted in freshwater systems, especially in the Philippines. Here we determined for the first time the amount of microplastics in the Philippines’ largest freshwater lake, the Laguna de Bay. Ten (10) sampling stations on the lake's surface water were sampled using a plankton net. Samples were extracted and analyzed using Fourier transformed infrared spectroscopy (FTIR). A total of 100 microplastics were identified from 10 sites with a mean density of 14.29 items/m3. The majority of microplastics were fibers (57%), while blue-colored microplastics predominated in the sampling areas (53%). There were 11 microplastic polymers identified predominantly polypropylene (PP), ethylene vinyl acetate copolymer (EVA), and polyethylene terephthalate (PET), which together account for 65% of the total microplastics in the areas. The results show that there is a higher microplastic density in areas with high relative population density which necessitates the implementation of proper plastic waste management measures in the communities operating on the lake and in its vicinity to protect the lake's ecosystem services. Furthermore, future research should also focus on the environmental risks posed by these microplastics, especially on the fisheries and aquatic resources.

This work reports the influence of precursor concentration on the thermal and optical properties of magnetic iron oxide nanoparticles (MIONPs) synthesized via the green synthesis route. A brown seaweed (Sargassum crassifolium) extract was used to mediate the reduction of iron precursors. Ultraviolet–visible spectra showed a sharp peak between 315 and 375 nm, which corresponds to the absorbance of MIONPs. This peak intensified with an increasing concentration of iron precursors. The Fourier transform infrared spectra revealed the presence of the transmittance bands around 557 cm−1 and 565 cm−1, which corresponds to Fe-O-Fe vibrational modes suggesting the successful formation of iron oxide nanoparticles. The dynamic light scattering technique revealed that the average hydrodynamic size of the MIONPs was 31.96 ± 15.61 nm and 147.40 ± 28.48 nm. Atomic force micrograph and scanning electron micrograph both showed quasi-spherical nanostructures with sizes ranging from 40 to 215 nm. Furthermore, X-ray diffraction and thermogravimetric analyses revealed the crystallinity and thermal stability of the synthesized MIONPs, respectively. This investigation on the effect of precursor concentration provides a valuable insight for the green- mediated synthesis of MIONPs that is vital for various environmental, biomedical, and industrial application.

The influence of cellulose fibers extracted from pineapple (Ananas comosus) leaf fibers on polyurethane foam’s mechanical properties (PUF) is reported. The PUFs were reinforced with different weight ratios (1, 3, and 5 wt%) of cellulose fibers. The surface morphology of the extracted cellulose fibers was determined using a scanning electron microscope (SEM). The functional groups and vibrational modes of the reinforced PUFs were measured using Fourier transform infrared spectroscopy (FTIR). The influence of cellulose fibers to the density and mechanical property of the PUFs were also investigated using universal testing Machine (UTM). Experimental results showed the absence of hemicellulose, lignin, and other soluble materials present in the pineapple leaves after alkaline treatment, suggesting high-quality cellulose fibers. Likewise, FTIR spectra revealed the presence of typical urethane linkages of PUFs suggesting the successful formation of PUFs with a varied amount of cellulose fibers. The mechanical properties of the PUFs with an increasing amount of cellulose fibers exhibit a decrease of the compressive strength of the fabricated PUFs may be due to the lack of cross-linking between the cellulose fibers and PUFs that will influence the reactivity in the system that eventually affects the polyurethane foam density expansion.

Cyanide ( CN - ) is a deleterious chemical and can cause serious health effects upon exposure even at low concentrations. Different sensors have been developed to monitor cyanide in water, which, however, suffers from complex mechanisms and high-cost. Curcuma longa or turmeric is a commercially available natural dye (usually in powder form) used as medicine. The phenolic substance curcumin is responsible for its yellow color and is capable of sensing environmentally significant analytes such as CN - . In this study, a colorimetric sensor for cyanide in aqueous solution was fabricated by the immobilization of crude curcumin on ordinary filter paper. The curcumin was extracted from locally available turmeric powder using a simple extraction method. Its successful integration in the filter paper was validated by FT-IR spectroscopy. UV–Vis analysis showed that the curcumin-based paper sensor was sensitive to CN - (down to 5.0 ppm), producing a visual change from yellow to dark red. The fabricated sensor also demonstrated high selectivity towards CN - in the presence of N a + , K + , and F - . Its response time was found to be inversely proportional to the concentration of the CN - in the solution. Assessment of reusability revealed that the sensor was reusable for up 8 cycles before significant changes in colorimetric response were observed. Importantly, the fabricated sensor exhibited applicability for actual cyanide monitoring in real water samples.

Increasing anthropogenic and industrial activities lead to the contamination of aquatic resources with organic pollutants such as dyes. In this work, a magnetic composite photocatalyst composed of Fe3O4, BiOCl, and Cu2O was fabricated for the degradation of organic dye pollutants. The composite was synthesized via a simple co-precipitation method. FT-IR and SEM-EDX analyses confirmed the formation of Fe3O4/BiOCI/Cu2O (FBC) composite. Photocatalytic degradation was tested under UV, and visible light using model organic dyes, methyl orange (MO), and methylene blue (MB), and was monitored using UV–Vis spectroscopy. The absorbance was found to decrease corresponding to the reduction of dye concentration during photocatalytic degradation. A plot of absorbance versus irradiation time for both model dyes exhibited exponential decay; faster degradation was observed with MO than with MB. Furthermore, the degradation of both dyes using the FBC photocatalyst was more efficient under UV light.

Use of cyanide in developing countries is rampant, especially in gold mining areas. Though it could cause serious environmental problems, cyanide contamination is of less priority for government monitoring because of the limited resources. The current detection and monitoring schemes of cyanide are the conventional and expensive laboratory-based methods, which need technical capabilities to conduct the actual testing and preparing manual data recording, making it tedious and too laborious. More efforts were directed towards digitizing the data recording from manual laboratory analyses as the manual data recording usually cause problems like delayed information, lost data, and erroneous data entry. Hence, the goal of this study is to provide a cost-effective and zero manual-recording measurement method for cyanide in water samples. This work focuses on the design of electrochemical measuring devices with the same capability with the portable or benchtop-type of cyanide meter but with an automated and realtime data recording using global system for mobile communications (GSM) technology. Results of this study showed that with the existing GSM technology and infrastructure of the new monitoring system, the measurements are comparable to that of a commercial bench-type cyanide meter with an R-squared (R2) of 0.9907. It was also noted that data being recorded were intact during wireless transmission testing using the GSM Network. The results obtained suggest that wireless communication using GSM Technology could be applied to environmental monitoring. Importantly, the newly developed online system for cyanide monitoring offers significant advantages over the conventional techniques such as low-cost, easy deployment, and ease of use. It can increase spatiotemporal data for better analysis of the data. The automated data acquisition and display through cellular phones are also made readily-available.

PCM (phase-change memory) is a memory innovation that has gained prominence as a capacity-class memory for computer systems. It is made up of a tiny functional amount of phase-change material that is located in the middle of two electrodes. In PCM, data is kept by utilizing the difference in electrical resistance between a crystalline phase, which has a high resistance, and its amorphous phase, which has a low resistance. Using electrical pulses, the phase-change material would be shifted from a high to the low conductive region and conversely. However, the device’s material science concerned with PCM has been generally studied, and questions remain regarding their electrical, warm, and fundamental aspects since its publication in the 1960s. One major downside of PCM is its low heat conductivity, which causes delays in the energy charging/discharging procedure and hardware efficiency. As a result of this, one of the primary focuses of PCM studies has been the improvement of PCM’s heat conductivity through the utilization of nanotechnology and nanomaterials. Nanotechnology has been developing ultrasmall nanoparticles to improve traditional PCMs’ thermophysical characteristics. These nanomaterials, such as metal, metal oxide, and carbon, will significantly boost PCM’s thermal properties, including supercooling, viscosity, and heat capacity. An overview of PCM devices is presented in this article, which underlies perusing and composition activities. Consequently, we offered novel PCM devices and materials. Therefore, the total study is qualitative, and no machine learning approach is used. Because of this, we cannot say that the data is quantitative. Our work includes both test representations of the specific features observed in nanoscale PCM devices and material science demonstrations. In the end, we provide a point of view on some remaining open inquiries and possible future exploration directions.

This paper reports on the synthesis and application of Fe3O4/TiO2 nanocomposite. In situ attachment of TiO2 coating to the surface of the magnetic nanoparticles (Fe3O4) was attained by direct condensation of titanium precursors. Characterization result suggests that the average particle size of the synthesized nanocomposite is 10-15 nm. Also, FT-IR result confirms the presence of TiO2 layer in the surface of the magnetic nanoparticles. Furthermore, the prepared Fe3O4/TiO2 nanocomposite was utilized as an active magnetic nanophotocatalyst for the degradation of cyanide. Results show that even at 5.0 mg of Fe3O4/TiO2 photocatalyst, higher cyanide removal efficiency (91%) was obtained when 60 ppm CN- was incubated with the photocatalyst for 30 minutes. Likewise, it has been demonstrated that the synthesized magnetic nanophotocatalyst can be used to degrade cyanide using sunlight as the natural light source. A 94% cyanide removal efficiency was obtained when the sample was incubated with the synthesized magnetic nanophotocatalyst for 120 minutes under sunlight irradiation. Importantly, the prepared magnetic photocatalyst can be re-used several times (up to 5 cycles) without significant changes in the cyanide removal efficiency.

We report on the growth of zinc oxide/polyaniline (ZnO/PANI) nanocomposites deposited on platinum (Pt)–coated glass substrate via chemical bath deposition and dip–casting technique is reported. Scanning electron micrographs of the nanocomposites revealed that etching of ZnO nanorods takes place during growth which turn into plate–like and distorted nanostructures. We found out that increasing the concentration of NH4OH triggered increase in nanostructure diameter. The surface morphology of nanocomposites significantly changed as the molar concentration of NH4OH precursor varies. Fast fourier transform infrared spectroscopy results showed the interaction of ZnO and PANI by observing the shift of peaks to the higher wavenumbers. The measured optical band gap of the nanocomposites are in good aggreement with the reported values. This result indicates that the grown ZnO/PANI nanocomposites is a good material for solar cell device.

We report on antibacterial activities of Zinc oxide (ZnO) with different structures. Fast furrier transform infrared spectroscopy ZnO nanostructures showed peaks in the range between 450–600 cm-1 indicating the successful growth through the presence of Zn-O stretching. On the other hand, impurities such as zinc complexes might be present due to the appearance of peaks at 1110 cm-1, 1390 cm-1 and 1506 cm-1. Furthermore, SEM images revealed that nanorods and sea-urchin like nanostructures are present in the produced ZnO nanostructures. Nanorods exhibit a better antibacterial response than the sea-urchin like structure. The change in structural morphology along with its purity has greatly influenced the area of bacterial inhibition zone during antibacterial testing.

This work reported the influence of seaweed (Sargassumcrassifolium) extract on the absorption of magnetic iron oxide nanoparticles (MIONPs) via green synthesis route. The seaweed extract acted as reducing and capping agent. Ultraviolet-visible (UV-Vis) spectra revealed the presence of sharp peaks at around 366 nm to 371 nm which corresponds to the absorption spectra of MIONPs. The absorption peaks corresponding to MIONPs was significantly affected by the varying amount of seaweed extract. On the other hand, Fourier Transform-Infrared (FTIR) spectra revealed the presence of the vibration mode around 532 cm-1 to 551 cm-1 which corresponds to Fe-O bands suggesting the successful formation of MIONPs. Thermogravimetric (TGA) spectra showed that the produced MIONPs stabilizes at 400 °C. The synthesized MIONPs are spherical in shape with an estimated average diameter of 20 nm as revealed by the Field Emission Scanning Electron Microscopy (FESEM). Finally, the produced MIONPs exhibit magnetic property via attraction with an external magnet. This straight forward green synthesis of MIONPs can be a good route for possible industrial and environmental application.

We report on the rigid polyurethane foam (RPUF) with varying amount of blowing agent. The effects of blowing agent in the formation of polyurethane will be characterized using scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. SEM images revealed that varying the amount of blowing agent will significantly change the surface morphology of the resulting RPUF. The average cell size of the RPUF increases with increasing amount of blowing agent. Moreover, FTIR results revealed the presence of functional group related to formation of urethane bonds such as N-H, C=O, C=N and C-O-C stretching suggesting that polyurethane foam was successfully synthesized. This simple and straightforward process of RPUF using water as blowing agent will be economical.

We report on the effect of cellulose fibers on the formation of petroleum-based and bio-based polyurethane foams. The fabricated polyurethane foams (PUF) were done by reacting isocyanate with petroleum-based polyol and epoxidized soybean oil (ESBO)-based polyols via hand mixing. The addition of cellulose fibers extracted from pineapple (Ananas comosus) leaf was done to enhance the properties of the fabricated PUF. Experimental results revealed that surface morphology of the fabricated polyurethane foams with addition of cellulose fibers remain the well-defined cell structures as shown in the scanning electron micrographs although few cell ruptures were observed. Likewise, the presence of the vibrational modes of the NCO and OH were confirmed in the Fourier transform infrared (FTIR) spectra suggesting that successful formation of polyurethane foams takes place. The thermogravimetric results revealed that much higher thermal stability for the 100% ESBO-based PUF with cellulose fibers due to the presence of cellulose and triglycerides in the ESBO-based polyols which both degrades at higher temperature. This suggest that 100% ESBO-based PUF with cellulose fiber exhibit higher thermal stability provides promising application for thermal insulations.

Sago (Metroxylon sagu) pulp is a common agricultural product; however, its pulp (from the main plant part and bark) finds no essential use and is considered agricultural waste. In this study, cellulose nanocrystals (CNCs) were isolated from the main pulp and bark pulp of sago through bleaching, alkali treatment, and acid hydrolysis. The hydrolysis was performed with 64% (w/w) sulfuric acid. A considerable yield was obtained for the extracted CNCs, 65.36% for sago main pulp (SMP), and 77.43% for sago bark pulp (SBP), which are comparable to other previous reported protocol. FTIR analysis of the resulting CNCs showed similar vibration frequencies with α-cellulose. Concerning the spherulites, considerable size reduction was revealed in the Scanning Electron Microscopy (SEM) analysis after acid hydrolysis of α-cellulose to obtain CNCs. Importantly, an image from the Transmission Electron Microscope (TEM) showed bundles of the needle-like structure of the extracted CNCs, which is a characteristic image of the CNCs after hydrolysis. Thermogravimetric analysis (TGA) also revealed the stability of the CNCs. Elemental analysis via EDX showed that the two forms of nanocellulose from the derived CNCs possessed mostly carbon and oxygen. The small amount of α-cellulose obtained (3-8%) was attributed to the degradation of α-cellulose, which may have been caused by the alternative bleaching process employed. Despite this, a reasonably good percent yield for CNCs was extracted, demonstrating sago pulp's potential as a useful source of this cellulosic nanomaterial.

Viral diseases resulting to global pandemics occurring through the years have extremely affected the human population and global economies. With the rise of novel pathogenic viruses and resistance of the known ones to conventional drugs and medications, exploration of new materials with antiviral properties has become an expanding interest notjust in the field of biomedicine but also in materials science, particularly in nanotechnology. The unique physicochemical properties of nanostructures derived from gold and silver, and metal oxides have attracted considerable attention as novel antiviral nanomaterials. In this paper, we review the antiviral potential of plasmonic gold and silver, and metal oxide nanostructures against known human pathogenic viruses such as herpes, hepatitis, dengue, influenza, measles, human immunodeficiency virus, transmissible gastroenteritis virus and other viruses. Experimental investigations revealed the promising potential of both plasmonic and metal oxide nanostructures as antiviral agents. The mechanisms of antiviral action were found to vary for different nanomaterials and its target virus while some mechanisms remained unclear. The promising yet undeterministic antiviral potential of these nanomaterials paved a more interesting platform for further research and biomedical exploration.

Magnetic nano- and microstructures are considered as significant materials for the development of advanced devices for various applications. In this paper, we present the synthesis of magnetic iron oxide microstructures via green-mediated chemical reduction technique and the effect of brown seaweed (Sargassum. crassifolium) extract on their microstructural properties. Ultraviolet-visible spectroscopy results confirmed the successful formation of magnetic iron oxide, while Fourier transform-infrared spectroscopy revealed the incorporation of the functional groups from the brown seaweed extract. X-ray diffraction has further shown that the samples were crystalline, and scanning electron microscopy showed the formation of irregular clusters with sizes ranging from 65 $\mu$ m to 390 $\mu$ m. Interestingly, the sizes of the microstructures were significantly reduced as the volume of the brown seaweed extract was increased, and a significant increase in the size distribution was observed. Finally, further inspection at a higher magnification revealed that the samples were composed of irregular nanostructures, and were confirmed by atomic force microscopy. This work provides new insights on controlling the properties of magnetic iron oxide using “green” and facile strategies.

We report on the green synthesis of silver nanoparticles utilizing theP.purpureumleaf extract. Controlling the surface plasmon absorption of silver nanoparticles was achieved by regulating the amount of extract concentration and the molarity of silver nitrate solution. The surface plasmon absorption peak is found at around 430nm. The surface plasmon absorption peak have shifted to lower wavelength as the amount of extract is increased, while plasmon absorption peak shifts on a higher wavelength as the concentration of silver nitrate is increased before it stabilized at 430nm. This can be explained in terms of the available nucleation sites promoted by the plant extract as well as the available silver ions present in silver nitrate solution.

EnvironmentAsia, 13, 2, 88-100

In this study, a versatile sensing platform based on a commercially available filter paper for the development of a colorimetric sensor using label-free gold nanoparticles (AuNPs) for the detection of cyanide in water is presented. The developed sensor can be applied for the direct detection of cyanide from an aqueous sample efficiently in a wide concentration range. The synthesised AuNPs were found to have an average size of about 13.2 ± 2.65 nm with a surface plasmon resonance peak at around 525 nm. Successful integration of AuNPs on the WFP substrate was observed through the FESEM-EDX analysis and supported by the presence of an absorbance peak at about 528 nm on the spectrum of the WFP-AuNPs composite. The colour of the WFP-AuNPs composite changed from purple-red to white in the presence of cyanide. Using the paper-based sensor, the limit of detection is calculated to be 7.68 × 10−6 M (0.5 ppm). The said sensitivity is good enough for the determination of cyanide in industrial wastewater samples. The developed sensor also showed excellent selectivity towards cyanide over other ions, demonstrating its practical applicability to monitor cyanide contamination in different environmental samples. Furthermore, the applicability of the sensor was demonstrated using several real water samples spiked with cyanide, including creek and tap water. Notably, the sensor showed great promise for the rapid, cost-effective, and versatile monitoring of cyanide contamination in various aqueous samples.

This work presents the synthesis of silver nanoparticles (AgNPs) capped with polyvinylpyrrolidone (PVP) via a simple chemical reduction approach. A route in controlling the optical absorbance of the AgNPs by varying the concentration of silver precursors, as reflected by the shifts and broadening of the UV-vis spectra of the AgNPs is also highlighted. Dynamic Light Scattering results revealed the narrow and small hydrodynamic size for AgNPs synthesized at low precursor concentration, while multiple hydrodynamic size peaks were observed for AgNPs produced at high precursor concentration. Likewise, Fourier transform-infrared spectroscopy confirmed the successful capping of PVP on the AgNPs through the O and N atoms as potential binding sites. Transmission electron micrographs revealed the formation of spherical PVP-capped AgNPs, having no apparent aggregation observed. A closer inspection of the micrograph showed the subsequent formation of rod-like growth template of the AgNPs, that might lead to the formation of non-spherical silver nanostructures.

Understanding the functional role of glycosylation-mediated pathogenesis requires deep characterization of glycoproteome, which remains extremely challenging due to the inherently complex nature of glycoproteins. We demonstrate the utility of lectin-magnetic nanoprobe (MNP@lectin) coupled to Orbitrap HCD-CID-MS/MS for complementary glycotope-specific enrichment and site-specific glycosylation analysis of the glycoproteome. By three nanoprobes, MNP@ConA, MNP@AAL, and MNP@SNA, our results revealed the first large-scale glycoproteome of nonsmall cell lung cancer (NSCLC) with 2290 and 2767 nonredundant glycopeptides confidently identified (Byonic score ≥100) in EGFR-TKI-sensitive PC9 and -resistant PC9-IR cells, respectively, especially with more fucosylated and sialylated glycopeptides in PC9-IR cells. The complementary enrichment was demonstrated with only five glycopeptides commonly enriched in three MNP@lectins. Glycotope specificity of 79 and 62% for enrichment was achieved using MNP@AAL and MNP@SNA, respectively. Label-free quantitation revealed predominant fucosylation in PC9-IR cells, suggesting its potential role associated with NSCLC resistance. Moreover, without immunoprecipitation, this multilectin nanoprobe allows the sensitive identification of 51 glycopeptides from 10 of 12 reported sites from onco-protein EGFR. Our results not only demonstrated a sensitive approach to study the vastly under-represented N-glycoprotome but also may pave the way for a glycoproteomic atlas to further explore the site-specific function of glycoproteins associated with drug resistance in NSCLC.