Faculty of Humanities and Sciences-Q1
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Publication Open Access Chitosan-Starch Biocomposite for Enhanced Curcumin Delivery: Kinetic Modeling of pH and Ionic Strength Responsive Release and Evaluation of Biological Efficacy(American Chemical Society, 2026-07-21) Abeywickrama, L; Wijayawardana, S; Thambiliyagodage, C; Jayanetti, MA drug delivery system composed of chitosan and starch was used to deliver curcumin effectively by enhancing its pharmacokinetic properties. The sustained release of the synthesized delivery system was evaluated using a kinetic modeling approach along with its biological efficacy. The SEM analysis confirmed the coupling of starch and chitosan and loading of curcumin into the matrix during synthesis. Crystallographic orientation of the delivery system was confirmed by XRD, and the FT-IR data confirmed the successful loading of curcumin. TG analysis indicated that the increment in decomposition temperature of the composite is due to the incorporation of curcumin into the composite. BET analysis revealed the reduction in the BET surface area and pore volume in the synthesized composite, confirming successful loading. The IC50 values of the curcumin and composite for the DPPH assay were 17.81 μg/mL and 38.77 μg/mL, respectively. Composite material has shown enhanced antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa at 20 mg/mL, with inhibition zones of 15.56 ± 0.29 and 10.11 ± 0.44 mm, respectively. Allium cepa cytotoxicity assay confirmed that all the synthesized materials promote mitosis at 2.5 mg/mL concentration. The pH and ionic strength responsive release of curcumin was studied by fitting the release data into six kinetic models, including Korsemeyer–Peppas (KP) and Peppas–Sahlin (PS), which has not been reported earlier for the synthesized system. The KP and PS models were selected to interpret the release mechanism based on R2. A combination of Fickian diffusion, relaxation and swelling dominates the curcumin release. According to the KP model, quasi-Fickian diffusion is responsible for the release in acidic and alkaline pH, whereas non-Fickian diffusion occurs at pH 6.7. At higher [NaCl], relaxation is responsible for the release (n > 0.43, kD = 0), while a combination of diffusion and relaxation governs the release at lower [NaCl]. These behaviors are related to the chemical composition of chitosan and the release media, where the electrostatic repulsion, protonation and charge screening contribute to curcumin release.Publication Open Access Copper-Based Nanoparticles as Precision Nanoantibiotics against Bacterial Blight in Anthurium andraeanum Lind.: Synthesis, Characterization, and Antibacterial Efficacy under In Vitro and In Vivo Conditions(American Chemical Society, 2026-05-05) Wanaguru, S; Jayasinghe, S; Seneviratne, K; Kottegoda, N; Peiris, Sriyani E; Peiris, Colin NThe bacterial blight disease caused by Xanthomonas spp., a dilemma for farmers worldwide. The existing conventional methods have failed to effectively combat the disease. Therefore, it is crucial to focus on developing and implementing more affordable techniques to effectively manage bacterial blight effectively. Herein, we investigated the efficacy of copper-based nanoparticles (Cu NPs) synthesized via three different methods toward controlling bacterial blight disease in Anthurium andraeanum plants. For that, Cu NPs were engineered via chemical, semichemical, and green synthesis approaches. Cu NPs were characterized through scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier-transform infrared (FTIR), and powder X-ray diffraction (PXRD) analysis. Quantitative antibacterial assays revealed that the chemical and green-synthesized Cu NPs exhibited the highest potency, with a minimum inhibitory concentration (MIC) of 31.25 μg/mL and a minimum bactericidal concentration (MBC) of 62.50 μg/mL, whereas the semichemical formulation showed lower activity (MIC = 62.50 μg/mL; MBC = 125 μg/mL). In vitro well-diffusion assays further supported this trend: at 30 ppm, the inhibition zones measured 25 ± 0.81, 15 ± 0.81, and 20.6 ± 0.94 mm for the chemical, semichemical, and green synthesis methods, respectively, compared to 26.3 ± 0.47 mm for the positive control-antibiotic sulfamethoxazole. At in vivo, optimized concentration of 200 ppm, Cu NPs produced via all three methods controlled bacterial blight disease in 90% of treated anthurium plants within 4, 7, and 5 weeks, respectively, without causing phytotoxicity. Disease progression was monitored over 12 weeks by measuring lesion areas, and statistical significance of treatments was determined using two-way analysis of variance (ANOVA). ©Publication Open Access Valorization of acid-hydrolyzed tea stem waste for sustainable biodiesel production using Chlorella vulgaris: a biorefinery approach(Frontiers Media SA, 2026-05-18) Dodangodage, C. A; Rathnapriya R.H.N.S.; Gamage, G. N; Kasturiarachchi, Jagath C.; Perera, Thilini A.; Rajapakshe, S. D; Niyangoda, Sayuri S.; Halwatura, R.UThe prohibitive cost of synthetic cultivation media remains a fundamental bottleneck in the commercial deployment of microalgal biodiesel. This study investigates the valorization of recalcitrant tea stem waste, an abundant agro-industrial by-product, as a low-cost, nutrient-rich medium for Chlorella vulgaris within an integrated biorefinery framework. Following thermochemical acid hydrolysis, a two-stage optimization of hydrolysate concentration and incident irradiance was conducted to maximize biomass production. Undiluted (100%) hydrolysate under elevated irradiance (240 µmol photons m-2 s-1) compensated for optical attenuation in the dark medium and yielded a maximum biomass concentration of 1.65 ± 0.07 g L-1, representing an approximately 5-fold increase over the synthetic Bold’s Basal Medium (BBM) control. Concurrently, substantial nutrient recovery was achieved, with 83.23% nitrate and 95.60% phosphate assimilation by Day 10. The resulting nutrient limitation acted as a secondary abiotic stressor, triggering enhanced intracellular lipid accumulation and yielding a peak volumetric lipid concentration of 0.094 ± 0.005 g L-1, approximately 4.5-fold higher than the autotrophic control. Fatty acid methyl ester (FAME) profiling revealed a saturated-dominant composition (85.57% SFA), corresponding to favorable predicted biodiesel properties, including low iodine value and high cetane number, consistent with international fuel standards. Overall, this study establishes tea stem hydrolysate as an efficient integrated cultivation matrix for simultaneous mixotrophic growth and lipid biosynthesis, advancing a scalable circular waste-to-energy pathway for agro-industrial systems.Publication Open Access Chitosan-Starch Biocomposite for Enhanced Curcumin Delivery: Kinetic Modeling of pH and Ionic Strength Responsive Release and Evaluation of Biological Efficacy(American Chemical Society, 2026-07-21) Abeywickrama, L; Wijayawardana, S; Thambiliyagodage, C; Jayanetti, MadaraA drug delivery system composed of chitosan and starch was used to deliver curcumin effectively by enhancing its pharmacokinetic properties. The sustained release of the synthesized delivery system was evaluated using a kinetic modeling approach along with its biological efficacy. The SEM analysis confirmed the coupling of starch and chitosan and loading of curcumin into the matrix during synthesis. Crystallographic orientation of the delivery system was confirmed by XRD, and the FT-IR data confirmed the successful loading of curcumin. TG analysis indicated that the increment in decomposition temperature of the composite is due to the incorporation of curcumin into the composite. BET analysis revealed the reduction in the BET surface area and pore volume in the synthesized composite, confirming successful loading. The IC50 values of the curcumin and composite for the DPPH assay were 17.81 μg/mL and 38.77 μg/mL, respectively. Composite material has shown enhanced antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa at 20 mg/mL, with inhibition zones of 15.56 ± 0.29 and 10.11 ± 0.44 mm, respectively. Allium cepa cytotoxicity assay confirmed that all the synthesized materials promote mitosis at 2.5 mg/mL concentration. The pH and ionic strength responsive release of curcumin was studied by fitting the release data into six kinetic models, including Korsemeyer–Peppas (KP) and Peppas–Sahlin (PS), which has not been reported earlier for the synthesized system. The KP and PS models were selected to interpret the release mechanism based on R2. A combination of Fickian diffusion, relaxation and swelling dominates the curcumin release. According to the KP model, quasi-Fickian diffusion is responsible for the release in acidic and alkaline pH, whereas non-Fickian diffusion occurs at pH 6.7. At higher [NaCl], relaxation is responsible for the release (n > 0.43, kD = 0), while a combination of diffusion and relaxation governs the release at lower [NaCl]. These behaviors are related to the chemical composition of chitosan and the release media, where the electrostatic repulsion, protonation and charge screening contribute to curcumin release.Publication Open Access Valorization of Canteen Wastewater Through Optimized Spirulina Platensis Cultivation for Enhanced Carotenoid Production and Nutrient Removal(Multidisciplinary Digital Publishing Institute (MDPI), 2026-01-14) Dodangodage, C. A; Gamage, G.N; Wijesekara, I.A; Kasturiarachchi, J.C; Perera, T.A; Rajapakshe, D; Halwatura, R.UThe valorization of nutrient-rich institutional effluents represents a promising route for sustainable algal biotechnology. This study investigates the potential of canteen wastewater (CW) as an alternative culture medium for Spirulina platensis, integrating wastewater treatment with high-value carotenoid and lipid production. Growth performance, biochemical composition, and nutrient removal efficiencies were systematically evaluated in 2 L photobioreactors under optimized conditions. Spirulina cultured in 75% CW under 180 μmol photons m−2 s−1 achieved a biomass productivity of 0.071 g L−1 day−1, nearly three-fold higher than the synthetic BG-11 control (0.023 g L−1 day−1). Nutrient remediation was highly efficient, with 92.12% nitrate and 90.05% phosphate removal, effectively reducing effluent concentrations below discharge limits. Biochemical profiling revealed that wastewater-grown biomass contained 54.3% protein and 7.85% lipids, with a remarkable carotenoid yield of 21.81 mg g−1 DW—significantly higher than the control (6.85 mg g−1 DW). Mechanistic analysis suggests that the balanced nutrient stoichiometry (C:N:P ≈ 30:4:1) and mixotrophic conditions enhanced biomass quality while mitigating ammonia toxicity. This study demonstrates the first integrated application of canteen wastewater for dual-purpose bioremediation and pigment-rich biomass production, establishing a scalable circular bioeconomy framework for institutional waste management.Publication Open Access Production of Carbohydrate-Rich Chlorella sp. Biomass Using Clarified Aquaponics Effluent for Bioethanol Feedstock Applications(Multidisciplinary Digital Publishing Institute (MDPI), 2026-03-26) Dodangodage, C. A; Gamage, G. N; Mallawa, L.C; Kasturiarachchi, J.C; Fernando, K. V; Halwatura, R.H; Perera, T.A; Rajapakshe, S.D; Niyangoda, S.S; Halwatura, R.UThe integration of microalgal cultivation with wastewater streams offers a promising pathway to enhance resource efficiency within circular bioeconomy frameworks. However, the suitability of clarified aquaponics sedimentation effluent for producing carbohydrate-rich microalgal biomass remains insufficiently evaluated, particularly with respect to nutrient recovery and bioethanol-relevant feedstock potential. In this study, clarified aquaponics sedimentation effluent was assessed as a cultivation medium for Chlorella sp. under controlled laboratory conditions. Biomass productivity, nutrient removal performance, and carbohydrate accumulation were systematically evaluated and compared with conventional synthetic medium. Chlorella sp. cultivated in clarified aquaponic effluent achieved a maximum biomass concentration of approximately 2.05 g L−1, exceeding that obtained in Bold’s Basal Medium. Carbohydrate content exceeded 40% of dry weight, indicating suitability for fermentable sugar production. Nitrate and phosphate removal efficiencies greater than 95% were achieved, with mass balance analysis confirming biological assimilation as the primary removal mechanism (~87.4%). This confirms the dual functionality of the system. The effective nutrient assimilation and confirmed the dual functionality of the system as both a biomass production and nutrient recovery process. Comparable performance under diluted and undiluted effluent conditions further indicated that freshwater dilution is not required following clarification. Light saturation was observed at 180–190 μmol m−2 s−1, providing guidance for energy-efficient operation. These findings demonstrate that clarified aquaponics effluent can serve as an effective alternative growth medium for producing carbohydrate-rich Chlorella sp. biomass while enabling nutrient recovery. The estimated bioethanol potential is theoretical, based on stoichiometric conversion assumptions, and experimental fermentation was not conducted. This work provides quantitative evidence supporting the integration of microalgae into aquaponic systems and establishes a foundation for future pilot-scale, techno-economic, and life-cycle assessments.Publication Open Access Integrated Microalgal–Aquaponic Systems for Enhanced Water Treatment and Food Security: A Critical Review of Recent Advances in Process Integration and Resource Recovery(Multidisciplinary Digital Publishing Institute (MDPI), 2026-01-12) Dodangodage, C.A; Kasturiarachchi, J. C; Wijesekara, I. A; Perera, T.A; Rajapakshe, D; Halwatura, RThe convergence of food insecurity, water scarcity, and environmental degradation has intensified the global search for sustainable agricultural models. Integrated Microalgal– Aquaponic Systems (IAMS) have emerged as a novel multi-trophic platform that unites aquaculture, hydroponics, and microalgal cultivation into a closed-loop framework for resource-efficient food production and water recovery. This critical review synthesizes empirical findings and engineering advancements published between 2008 and 2024, evaluating IAMS performance relative to traditional agriculture and recirculating aquaculture systems (RAS). Reported under controlled laboratory and pilot-scale conditions, IAMS have achieved nitrogen and phosphorus recovery efficiencies exceeding 95% while potentially reducing water consumption by up to 90% compared to conventional farming. The integration of microalgal photobioreactors enhances nutrient retention, may contribute to internal carbon capture, and enables the generation of diversified co-products, including biofertilizers and protein-rich aquafeeds. Nevertheless, significant barriers to commercial scalability persist, including the biological complexity of maintaining multi-trophic synchrony, high initial capital expenditure (CAPEX), and regulatory ambiguity regarding the safety of waste-derived algal biomass. Technical challenges such as photobioreactor upscaling, biofouling control, and energy optimization are critically discussed. Finally, the review evaluates the alignment of IAMS with UN Sustainable Development Goals 2, 6, and 13, and outlines future research priorities in techno-economic modeling, automation, and policy development to facilitate the transition of IAMS from pilot-scale innovations to viable industrial solutions.Publication Embargo Boosting CO2-to-C2H4 electrocatalysis on Cu2O with waste-derived porous carbon from coconut shells(Royal Society of Chemistry, 2026) Qin, C; Li, T; Masakorala, G; Zhi, C; Huang, H; Zhou, C; Wang, X; Shen, B; Zhang, Jian-Rong; Zhou, YThis study presents a sustainable strategy to boost CO2-to-C2H4 conversion by constructing Cu–C interfaces using Cu2O nanospheres supported on porous carbon derived from waste coconut shells. The Cu2O–10mgC catalyst achieves a 4-fold increase in FE(C2H4) compared with Cu2O and maintains >40% selectivity for 45 h. In situ spectra reveal enhanced *COLFB coverage, confirming that oxygen-rich functional groups at the Cu–C interface promote C–C coupling. This work demonstrates both the catalytic and economic feasibility of waste-derived carbon supports for efficient CO2-to-C2H4 conversion.Publication Open Access Early Diagnosis and Severity Assessment of Weligama Coconut Leaf Wilt Disease and Coconut Caterpillar Infestation Using Deep Learning-Based Image Processing Techniques(Institute of Electrical and Electronics Engineers Inc., 2025-02-03) Vidhanaarachchi, S; Wijekoon, J. l; Abeysiriwardhana, W. A. S. P ; Wijesundara, MGlobal Coconut (Cocos nucifera (L.)) cultivation faces significant challenges, including yield loss, due to pest and disease outbreaks. In particular, Weligama Coconut Leaf Wilt Disease (WCWLD) and Coconut Caterpillar Infestation (CCI) damage coconut trees, causing severe coconut production loss in Sri Lanka and nearby coconut-producing countries. Currently, both WCWLD and CCI are detected through on-field human observations, a process that is not only time-consuming but also limits the early detection of infections. This paper presents a study conducted in Sri Lanka, demonstrating the effectiveness of employing transfer learning-based Convolutional Neural Network (CNN) and Mask Region-based-CNN (Mask R-CNN) to identify WCWLD and CCI at their early stages and to assess disease progression. Further, this paper presents the use of the You Only Look Once (YOLO) object detection model to count the number of caterpillars distributed on leaves with CCI. The introduced methods were tested and validated using datasets collected from Matara, Puttalam, and Makandura, Sri Lanka. The results show that the proposed methods identify WCWLD and CCI with an accuracy of 90% and 95%, respectively. In addition, the proposed WCWLD disease severity identification method classifies the severity with an accuracy of 97%. Furthermore, the accuracies of the object detection models for calculating the number of caterpillars in the leaflets were: YOLOv5-96.87%, YOLOv8-96.1%, and YOLO11-95.9%.Publication Open Access Prevalence, nature and impacts of non-sexual online harassment in Sri Lanka: A quantitative analysis(Elsevier Ltd, 2025-10-20) Harasgama, K. S.; Karunasena, K; Senarath, S; Jayamaha, S; Mahingoda, C.B; Deshapriya, WThe objective of this study is to examine the prevalence, nature and impacts of nonsexual online harassment among the youth population in Sri Lanka. Data was collected through a countrywide survey from a cross-sectional sample of 4805 young people. Data was analysed using SPSS software package. Results of this study indicate that 11.7 % of the youth population surveyed had experienced non-sexual forms of harassment in the cyberspace. The analysis also revealed the most common types of harassment experienced, the platform where harassment was committed the most, the most common types of victims and perpetrators, and the impacts of non-sexual online harassment on victims. The findings of this study suggest that Sri Lanka needs to devise targeted policies for combatting non-sexual online harassment, and that it may need to tailor its responses to the needs of each sector.