Advancements in diagnostic approaches for malaria and dengue fever cases in Indonesia and Nigeria

Background: This review aims to compare diagnostic advancements for malaria and dengue fever in Indonesia and Nigeria, highlighting the implementation of AI-based technologies and electrochemical biosensors. Both diseases are endemic in these tropical countries and present overlapping clinical symptoms, making laboratory-based confirmation methods such as RT-PCR and serological assays critical for accurate diagnosis. Methods: A structured literature review was conducted using Scopus, PubMed, and IEEE Xplore databases, focusing on peer-reviewed studies published between 2015 and 2024 that reported diagnostic performance and field applicability of the technologies. This scientific review synthesizes existing literature on infection mechanisms, conventional diagnostic methods (microscopy, RDT, ELISA, PCR), and state-of-the-art sensing technologies, including the AI-based malaria detection system (AIDMAN: YOLOv5 + Transformer + CNN) and electrochemical biosensors for dengue. Findings: The AI approach for malaria achieved high accuracy (patch-level 98.62% AUC 99.92%; image-level 97% AUC 98.84%). Dengue NS1 electrochemical biosensors reached a detection limit of ~10⁻¹² g/mL with excellent sensitivity and reproducibility, suitable for point-of-care use. Conclusion: Integrating sensing technologies from rapid tests to AI-driven microscopy and biosensors enables faster, more accurate diagnosis, improving patient management in resource-limited settings. Novelty/Originality of this article: This is the first comprehensive review that bridges cross-country (Indonesia and Nigeria) and cross-technology (AI and biosensor) approaches, offering valuable insight into sustainable diagnostic innovation for tropical infectious diseases

Uncovering the spatial link between environmental risks, diarrhea incidence, and health service accessibility

Background: This study investigates spatial disparities between healthcare capacity, hospital accessibility, and environmental risk of diarrhea in West Java Province. Using a combination of Geographic Information System (GIS), network-based travel-time modeling, Principal Component Analysis (PCA), and clustering, the research identifies mismatches high-risk areas and low-access healthcare infrastructure. Spatial overlay reveals that districts such as Tasikmalaya, Garut, and Cianjur experience dual vulnerabilities—limited healthcare reach and elevated environmental risk indicators. Methods: PCA was used to reduce multicollinearity among six environmental and socioeconomic variables, including access to sanitation, drinking water, latrine type, and poverty level. After excluding three extreme outliers, 24 districts were clustered using PCA-derived composite scores. The clusters were overlaid with hospital accessibility maps from service area analyses (≤30 and 31–60 minutes). PCA explained 80.4% of the total variance. Findings: The results show that 3 out of 27 districts, such as Tasikmalaya, Garut, and Cianjur; exhibited critically low hospital bed ratios, and over 50% of their population is located outside the 30-minute service area of a hospital. PCA-based clustering revealed four spatial risk typologies, with Cluster 4 (extreme outliers) representing the highest composite risk from poor sanitation, communal latrines, and high poverty. These findings underscore a spatial mismatch between environmental vulnerability and healthcare accessibility. Conclusion: Integrated spatial planning is urgently needed in high-risk, low-access areas, combining infrastructure expansion with digital health solutions. Novelty/Originality of this article: This study introduces a spatial typology of diarrhea risk in West Java by integrating PCA and GIS-based accessibility, and aligns its recommendations with Indonesia’s national health policy frameworks (RPJMN 2025–2029 and PP No. 28/2024) to support data-driven, equitable public health interventions

A review of TiO2 nanotubes/Co3O4/M (M: Au, Ag) photoelectrode for degradation of methyl orange and methylene blue

Background: Wastewater containing dyes occurs due to the discharge of wastewater into rivers without undergoing proper treatment procedures as it should. This waste generally comes from the textile industry. Wastewater containing dyes increases the concentration of organic pollutants in wastewater, which can cause water pollution. Textile dyes are generally made from compounds containing aromatic rings, such as methyl orange and methylene blue. Methyl orange and methylene blue are organic pollutants that cannot be biologically degraded because they contain aromatic rings that are difficult to break down, thus posing a risk of environmental pollution and disrupting aquatic ecosystems. Several conventional wastewater treatment methods for dye degradation, such as coagulation, flotation, sedimentation, and filtration, have been applied, but these methods still have limitations. Methods: This review examines recent progress in the development of TiO₂ nanotube-based photoelectrodes modified with Co₃O₄ and noble metals (Ag, Au) for the degradation of methyl orange and methylene blue from wastewater. The use of electrochemical methods has advantages over conventional methods, namely more efficient, environmentally friendly, and flexible for the degradation of dyes in wastewater. The synthesis techniques used are anodization, impregnation-deposition-decomposition, and photodeposition methods. Findings: The development of TiO₂/Co₃O₄/Ag and TiO₂/Co₃O₄/Au nanotube-based photoelectrodes shows better performance in the degradation of organic dyes compared to unmodified TiO₂ photoelectrodes, as they can improve photocatalytic efficiency by expanding visible light absorption and increasing surface reactivity. Conclusion: The use of TiO₂/Co₃O₄/Ag and TiO₂/Co₃O₄/Au materials has great potential as an environmentally friendly and efficient solution in addressing pollution from persistent textile dye wastewater. The implementation of this technology in industrial wastewater treatment systems promotes advances in the fields of photocatalysis and renewable energy. Novelty/Originality of this article: This review is the first to evaluate TiO₂ nanotube/Co₃O₄ photoelectrodes modified with Ag and Au for the degradation of methyl orange and methylene blue

An acetylcholinesterase-based biosensor of carbofuran using carbon foam electrode modified by graphene and gold particles

Background: This study introduces a novel acetylcholinesterase (AChE)-based biosensor for the sensitive and selective detection of carbofuran, a widely used carbamate pesticide known for its neurotoxicity. Methods: The biosensor employs a carbon foam (CF) electrode modified with graphene oxide and gold nanoparticles (CF/Graphene/Au), leveraging the synergistic properties of these materials to enhance electrochemical performance. Carbofuran detection is achieved through its inhibitory effect on AChE activity, monitored via cyclic voltammetry of thiocholine oxidation. Findings: Under optimal conditions at pH 7.4, the biosensor demonstrated a linear detection range of 25–125 μM, a detection limit of 8.08 μM, and a sensitivity of 0.3874 mA μM⁻¹ cm⁻². It also showed strong reproducibility with a relative standard deviation of 6.77%. When tested on real vegetable samples, the biosensor achieved recovery rates between 88.95% and 111.30%. Conclusion: Compared to existing biosensor technologies, the CF/Graphene/Au-based sensor offers a well-balanced performance in terms of sensitivity, detection range, and practical usability. It presents a viable and portable solution for monitoring pesticide residues in environmental samples. Novelty/Originality of this article:  This work presents a promising, portable solution for environmental monitoring of pesticide residues, integrating advanced nanomaterials and computational validation to improve detection accuracy and reliability

Preliminary study of screen–printed gold electrode for H2O2 sensor based on electrochemiluminescence of luminol

Background: Hydrogen peroxide (H2O2) is mostly used in the water and dairy industries for sterilization and preservation purposes. However, excessive H2O2 residues in milk and tap water pose a health risk. Therefore, accurate measurement of H2O2 residue is essential.  Methods: This study explores the potential of a screen–printed gold electrode (SPGE) as a sensor for H2O2 sensor using the electrogenerated chemiluminescence (ECL) method of luminol in the electrolyte of phosphate buffer solution (PBS) under alkaline condition (pH of 9). Findings: The detection of H2O2 was achieved a linear calibration equation of y = 0.0215[H2O2] + 0.2006 within a concentration range of 0.5 to 200 µM (R2 = 0.9998), demonstrating reliable ECL measurements.  Conclusion: The analytical performance evaluation of H2O2 sensor exhibited a low limit of detection (LOD) of 3.06 µM, a limit of quantification (LOQ) of 10.20 µM, and good measurement repeatability, with a relative standard deviation (%RSD) of 6.03%, which is below ⅔ of the Horwitz coefficient of variation (9.85%). Unmodified SPGE offers simplicity, ease of use, a stable surface, and good conductivity while maintaining excellent performance. Novelty/Originality of this article: The application of the ECL method on SPGE for H2O2 detection offers excellent analytical performance, making it a promising approach for monitoring H2O2 residues in the water and dairy industries, with a recovery from 83.83 to 106.01%

A review of photoelectrochemical water oxidation using hematite photoanode

Background: The sun, as an abundant and renewable energy source, provides a sustainable alternative to fossil fuels, which contribute significantly to CO₂ emissions and global warming. With CO₂ emissions surpassing 35 billion tons in 2023, the need for clean energy solutions has become increasingly urgent. Solar energy utilization includes photoelectrochemical (PEC) water splitting, where hematite is widely recognized as an efficient photoanode material due to its availability, stability, and favorable band gap for visible light absorption. However, hematite faces challenges such as poor conductivity, surface recombination, and slow oxygen evolution reaction (OER) kinetics, which limit its performance. Methods: This review examines various strategies to enhance hematite photoanode performance for PEC water splitting. The study explores three key approaches: (1) using three-dimensional conductive substrates with high surface area to facilitate heterojunction formation, (2) doping with tetravalent metal ions (e.g., Ti⁴⁺) to improve conductivity and charge carrier density, and (3) integrating Bi₂WO₆ with hematite to enhance charge separation and photoelectrochemical efficiency. The hydrothermal method was applied for hematite fabrication due to its feasibility, cost-effectiveness, and scalability. Findings: The analysis highlights the effectiveness of each strategy in overcoming hematite’s inherent limitations. The use of 3D conductive substrates improves electron transport and surface reaction sites, while Ti⁴⁺ doping enhances charge carrier density and conductivity. Conclusion: Hematite remains a promising photoanode material for PEC water splitting, but its limitations must be addressed to maximize efficiency. The combination of 3D conductive substrates, metal ion doping, and Bi₂WO₆ integration has shown potential in improving hematite’s photoelectrochemical performance. Novelty/Originality of this article: This review provides a comprehensive analysis of hematite performance enhancement strategies, focusing on the synergistic effects of 3D conductive substrates, Ti⁴⁺ doping, and Bi₂WO₆ integration.

Advanced electrochemical detection of arsenic using platinum-modified boron-doped diamond by anodic stripping voltammetry

Background: Platinum-modified boron-doped diamond (BDD) electrodes were effectively fabricated through a combination of wet seeding and electrodeposition techniques. Methods: This research involved the utilization of various chemicals and apparatus, the modification of boron-doped diamond (BDD) electrodes with platinum using wet seeding and electrodeposition, and the detection of As3+ and As5+ using a phosphate buffer solution and anodic stripping voltammetry (ASV). Findings: Characterization using Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) confirmed the successful deposition of 1.54% platinum on the BDD surface. These modified electrodes were employed as sensors for arsenic species (As³⁺ and As⁵⁺) using anodic stripping voltammetry (ASV) in a 0.1 M phosphate buffer solution at pH 6. Under optimal conditions, including a deposition potential of -500 mV, a deposition time of 150 s, and a scan rate of 200 mV/s, the linear detection of As³⁺ and As⁵⁺ was achieved within a concentration range of 0 to 100 ppb (R² = 0.9797 and 0.9903, respectively). Prior to ASV detection of As⁵⁺, a pretreatment step involving the addition of 0.1 M NaBH₄ was necessary to reduce As⁵⁺ to As³⁺. The detection limits for As³⁺ and As⁵⁺ were determined to be 16.50 ppb and 8.19 ppb, respectively. Conclusion: This research highlights the potential of BDD/Pt electrodes in environmental monitoring and arsenic detection applications and demonstrates the method's efficacy for the speciation analysis of arsenic species. Novelty/Originality of this Study: This research pioneers the use of platinum-modified boron-doped diamond electrodes for the speciation analysis of arsenic, offering a promising new approach for environmental monitoring applications

Analysis of microbial diversity in pesticide-contaminated soil: A study of culturable microorganisms

Background: Pesticide contamination of soil often leads to significant alterations in the structure and diversity of microbial communities, potentially affecting overall ecosystem function. Understanding these changes is crucial for assessing the ecological impact of pesticide use in agricultural areas. This study analyzes microbial diversity in pesticide-contaminated soil using the Shannon-Wiener diversity index to evaluate the effects of pesticide exposure on microbial populations. Methods: A descriptive quantitative approach was used, incorporating the Total Plate Count (TPC) test and Shannon-Wiener Index analysis. The numerical data included the number of microbial individuals (bacteria and fungi) and the relative proportion of each group. Soil samples were purposively collected from three points in a pesticide-contaminated tomato farming area in Dunggala Village, Gorontalo Regency. Findings: The microbial community detected in the contaminated soil consisted of bacteria (2.5×10⁴ CFU/ml) and fungi (1.35×10³ CFU/ml). The Shannon-Wiener index value was 0.202, indicating low microbial diversity. This suggests that pesticide contamination negatively impacts microbial richness and evenness in the soil. Conclusion: Pesticide contamination significantly reduces microbial diversity, as reflected in the low Shannon-Wiener index value. This decline in microbial richness and evenness highlights the potential ecological consequences of pesticide use in agriculture. To mitigate these negative effects, implementing sustainable pest management practices, such as the use of biopesticides, is recommended. Novelty/Originality of this article: This study provides quantitative evidence of the decline in microbial diversity in pesticide-contaminated soil using the Shannon-Wiener index. By focusing on microbial community changes in a specific agricultural setting, the findings contribute to a better understanding of the ecological impacts of pesticide use and emphasize the need for sustainable pest management strategies

Bioremediation based on palm oil sludge as an intervention for heavy metal pollution risk in industrial residential

Background: The palm oil industry in Indonesia, often pollution the environment, especially water bodies, with waste containing hazardous metals. This can threaten the lives of aquatic organisms and damage ecosystems. Although the palm oil industry has become a pillar of the national economy with production reaching 46,986 tons in 2023, the waste problems generated, especially palm oil sludge, demand innovative and sustainable solutions. The limitations of existing technologies in handling heavy metal pollution drive the need for an interdisciplinary approach that not only reduces environmental risks but also provides economic added value through circular economy concepts and local resource empowerment. The aim of this study is to identify the characteristics of palm oil sludge-based bioremediation stones in the process of heavy metal adsorption. Methods: This study was conducted through descriptive analytical literature review with a qualitative approach. Findings: The results show that palm oil sludge-based bioremediation stones have microporosity characteristics and complex chemical compositions capable of absorbing heavy metals with efficiency reaching 85-92%. This innovation not only offers sustainable solutions, but also provides multidimensional benefits, including reduced public health risks and the creation of circular economic models. Conclusion: Through activation with sulfuric acid, the potential for heavy metal absorption can be increased by up to 35%, which implies a 70% reduction in environmental contamination in industrial areas. Novelty/Originality of this article: This innovation integrates an interdisciplinary approach combining environmental science, chemistry, and resource management, potentially creating a replicable risk intervention model for industrial areas, with economic value

Influence of NaBH4 on the sensitivity of As3+ and As5+ sensor using gold modified boron doped diamond electrodes

Background: Arsenic is known as one of the carcinogenic metalloids and can cause various health issues when ingested or inhaled over prolonged periods of time. Methods: In this work, boron-doped diamond (BDD) electrode was altered with gold particles (Au) arranged by seeding continued with electrodeposition of HAuCl4 solutions at the electrode surface, will be used as electrode to detect As3+ and As5+ in lake water. The deposited gold particles on the BDD surface were studied with scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS). Detections of As3+, As5+, and mixture solutions of As3+ and As5+, carried out with anodic stripping voltammetry (ASV). Findings: The, pre-treatment using NaBH4 carried out for reduction from As5+ to As3+, indicate an improvement at the sensitivity of As3+ and As5+ detection with a good linear responses for each solution in range concentrations of 0.02-0.2 ppm for As3+ and As5+, with R2=0.9759 and R2= 0.9876, respectively. Conclusion: Furthermore, limit of detections of 0.0335 ppm and 0.0239 ppm can be attained for As3+ and As5+ displayed high linearity, revealing that detection of each species of As3+ and As5+ can be conducted in mixture of As3+ and As5+. Novelty/Originality of this Study: This study involves the modification of BDD electrodes with gold (Au) using a combined seeding and electrodeposition technique, which enhances stability and sensitivity for detecting arsenic (As³⁺ and As⁵⁺) at low concentrations. Additionally, the research introduces a pretreatment method using NaBH₄ to facilitate the detection of As⁵⁺ by reducing it to As³⁺, thereby improving the detection limits with anodic stripping voltammetry (ASV)