Faculty of Humanities and Sciences-Scopus2
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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 Biochemical shifts in Chlorella vulgaris via post-stationary magnesium sulfate stress: optimizing biomass for advanced bio-fertilizers(Frontiers Media SA, 2026-06-09) Dodangodage, C. A; Kasturiarachchi, J. C; Perera, T.A; Rajapakshe, S.D; Niyangoda, S.S; Halwatura, R.USustainable agriculture requires bio-fertilizers that improve both nutrient efficiency and soil resilience. Microalgae are promising candidates; however, conventional optimization using sodium chloride (NaCl) stress introduces phytotoxic sodium residues that limit soil application. To address this, a biphasic cultivation strategy for Chlorella vulgaris was developed using magnesium sulfate (MgSO4) as a dual-function stressor. Following the onset of a nitrogen-limited stationary phase (Day 18), the addition of 0.4 g L-¹ MgSO4 induced intracellular macromolecular accumulation. Biomass increased by 44.8% (2.810 ± 0.090 g L-¹), driven by intracellular densification, with enrichment in both total carbohydrate (42.15 ± 2.10%) and lipid (36.24 ± 1.11%) fractions. Substituting NaCl with MgSO4 eliminates the risk of sodium-induced phytotoxicity upon soil application, while simultaneously pre-loading the biomass with essential secondary macronutrients. Overall, this study demonstrates that targeted MgSO4-induced metabolic shifts can generate high-density, functionally enhanced, sodium-free microalgal biomass to serve as a potential bio-fertilizer feedstock.Publication Open Access Novel mycelium-based composites with enhanced physico-mechanical properties, as sustainable alternatives for packaging applications(Taylor and Francis Ltd., 2026-07-17) Madusanka, C; Udayanga, D; Nilmini, R; Rajapaksha, S; Hewawasam, C; Manamgoda, D; Herath, I. SMycelium-based composites (MBCs) are produced through a combination of fungi and lignocellulosic materials. Identifying novel combinations of fungi and lignocellulosic waste is crucial for exploring new material properties. In this study, MBCs were prepared with strains of Ganoderma orbiforme and Lentinus squarrosulus from Sri Lanka, using three different types of locally sourced lignocellulosic substrates, including Cocos nucifera sawdust, Mangifera indica sawdust, and coir pith derived from coconut husk. Mycelium inoculum grown on rice seeds was introduced to organic substrates and incubated at 28 °C for 30 d. The resulting composites were separated from the container, dried at 80 °C, and characterised for physicochemical, and microscopic properties. Results indicated that the produced MBCs exhibit properties equivalent to or superior to those of expanded polystyrene (EPS). The Ashby chart generated revealed that MBCs possess properties comparable to cork and other low-density foams, making them suitable for insulating, cushioning, and packaging applications. Among the combinations tested, MBCs made with coir pith and coconut sawdust proved to be the most effective, eco-friendly alternatives to protective packaging.Publication Open Access Coordinated lignocellulolysis: topological analysis reveals coordinated lignocellulolysis in Klebsiella–Enterobacter-mediated rice straw degradation via surface delignification and cellulose crystallinity modulation(Microbiology Society, 2026-05-12) Senadheera, U. E; Jayasanka, D.J; Hewawasam, C; Udayanga, D; Takimoto, Y; Tadachika, NSurface-sterilized Oryza sativa AT362 straw was screened for endophytic ligninolytic and cellulolytic bacteria using colour unit reduction and Congo Red decolorization assays. Ligninolytic Klebsiella variicola AKL1104 and cellulolytic Enterobacter chuandaensis AKC1108, biocompatible, were inoculated at a 1:1 ratio and incubated in 1% (w/v) rice straw broth at 37 °C for 7 days. Topological changes due to degradation were conducted using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) for 9 days. During t=9 d, SEM shows vascular tissue perforation with tunnels, indicating K. variicola mediated-delignification, allowing E. chuandaensis to sequentially degrade cellulose. XRD revealed a cellulose crystallinity decline from 30.08% on t=0 d to 11.76% on t=9 d. Electron microscopy and crystallite size calculations in t=6 d (6.81 nm) and t=9 d (90.16 nm) indicate self-assembly of cellulose fibrils. FTIR and XPS analysis indicated crystalline cellulose transformation to amorphous cellulose as the lateral order index dropped from 0.776±0.006 to 0.503±0.007, while surface lignin coverage was reduced from 5.01 to 2.20%, respectively.Publication Open Access A novel solid-state, multi-layered biodegradable microbial inoculant system for rice straw composting: biocapsule design, characterization, and performance evaluation(Frontiers Media SA, 2026-04-17) Senadheera, U. E; Jasintha Jayasanka, D; Hewawasam, C; Udayanga, D; Takimoto, Y; Nakayama, TLignocellulolytic microbial inoculants are widely used to enhance lignocellulosic waste composting, but their efficacy is often limited by environmental stress and uncontrolled release when conventional liquid inoculants are used. This study introduces a multi-layered biocapsule structure that sustains lignocellulolytic microbial activity and evaluates its composting efficiency through control experiments. A three-layered biodegradable biocapsule was designed using a rice straw biocomposite, humic acid, activated carbon, corn starch, carboxymethyl cellulose, and calcium alginate beads with encapsulated Klebsiella–Enterobacter consortium immobilized on hydroxyapatite nanoparticles. The biocapsule comprises a rice straw outer biocomposite shell in the outermost layer, a moisture retention hydrogel in the middle, and the encapsulated bacteria in calcium alginate beads in the core. The designed biocapsule was used in three treatments: intact biocapsule, powdered biocapsule, and a control (without inoculants), and the composting efficacy was evaluated against Sri Lankan Standards for compost products. Calcium alginate beads achieved 78.29% ± 9.57% and 84.45% ± 6.04% bacterial encapsulation efficiency and bacterial release, respectively, with heavy bacterial colonization in beads. The entire biocapsule reached 56.16% ± 1.65% biodegradation in 7 days. Intact biocapsule enhanced early lignocellulolysis, faster pH neutralization, and reduced electrical conductivity to 0.62 ± 0.00 while sustaining prolonged thermogenesis above 55 °C for 25 days. The intact biocapsule significantly improved compost nutrient availability, increasing total nitrogen, phosphorus, and potassium levels by 71.89%, 83.0%, and 60.66%, respectively, while achieving a total organic carbon loss of 53.30% and a Carbon: Nitrogen ratio decline of 72.83%.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 Biocompatibility vs antibacterial activity: chitosan-mediated nanosilver/PCL/gelatin nanofibers(Taylor and Francis Ltd., 2026) Chandraguptha, D; Fernando, L; Herath, L; Godakanda, V. U; Perera, N; Samarakoon, S; de Silva, K. M. N; Williams, G.R; de Silva, W. R.MElectrospinning is an efficient approach to prepare nanofiber scaffolds that mimic local tissue environments. While many reported scaffolds incorporate nanoparticles, detailed assessments of how nanosilver distribution affects antibacterial activity and biocompatibility remain limited. In this study, we developed an electrospun biopolymer scaffold composed of polycaprolactone and gelatin with chitosan-mediated nanosilver (C-AgNPs), introduced either by bulk surface coating or by dispersing the NPs within the electrospinning solution. The C-AgNP surface-coated scaffold exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas the dispersed scaffold did not. However, the dispersed scaffold promoted higher dermal fibroblast viability (82.7%) compared with the coated scaffold (60.9%). Zebrafish embryo assays further revealed mild developmental toxicity from the coated scaffold but no observable toxicity from the dispersed formulation. These findings demonstrate a distinct trade-off between antibacterial efficacy and cytocompatibility depending on nanoparticle distribution. Understanding this relationship is critical for designing electrospun nanofiber scaffolds with balanced biological properties.Publication Open Access Coconut Shell Waste-Derived Porous Carbon-Supported Sn Catalysts for Efficient Electrochemical CO2Reduction to Formic Acid and Deuterated Formic Acid(American Chemical Society, 2025-11-05) Qin, C; Masakorala, G; Mohideen, M; Samarasekara, T; Zhang, L; Zhu, W; Zhou, Y; Thambiliyagodage, CIndustrial-level electrochemical CO2 reduction reaction (CO2RR) to form HCOO– and DCOO– requires robust Sn catalysts with high performance. In this study, the hydrothermal method was employed to load varying amounts of Sn precursors onto waste biomass-derived porous carbon to investigate the structure–activity relationship between Sn loading forms and HCOO– selectivity. Through comprehensive ex/in situ characterizations, we discovered that with 5% Sn precursor addition, highly dispersed SnO2 nanoparticles formed on the carbon support, enabling the catalyst to exhibit exceptional HCOO– activity (Faradaic efficiency exceeding 90%) across a broad potential window. In situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and in situ Raman spectroscopy revealed that the highly dispersed SnO2 nanoparticles enhance the stability of the *OCHO intermediate. Furthermore, when H2O was replaced with D2O, the generation of DCOO– was observed, and good selectivity was maintained. This study provides a facile strategy for waste biomass conversion and the design of Sn-based catalysts for DCOO– production.Publication Open Access ZIF-8 confined carbon dots/bilirubin oxidase on microalgal cells to boost oxygen reduction reaction in photo-biocatalytic fuel cells for pollutants removal(Elsevier B.V., 2026-01) Qing, S; Lu, X; Jiang, Y; Thambiliyagodage, C; Song, B; Xia, A; Zhang, J.R; Zhu, W; Jiang, L.P; Wu, XPhotocatalytic fuel cells provide promising opportunities for sustainable wastewater treatment and energy conversion. However, their applications are challenged by the sluggish oxygen reducton reaction (ORR) kinetics at cathodes owning to the low O2 solubility and diffusion rate. Herein, we proposed a photo-biocatalytic fuel cell (PBFC) with a novel hybrid biocathode based on artificially engineered algal cells coated by ZIF-8 confined carbon dots/bilirubin oxidase (ZIF-8/CDs/BOD@algae). Microalgae absorbed CO2 and provided O2 in situ for BOD catalysts. Due to effective absorption of O2 by imidazole and confinement of hydrophobic porous ZIF-8, oxygen diffusion has been accelerated in MOF/enzyme systems. Importantly, the introduction of CDs alleviated the poor conductivity of ZIF-8 and improved the electron transfer rate of BOD. Thus, the biocathode exhibited a high current density of 1767 μA/cm2, a 2.26-fold increase compared with that of CDs/BOD/algae biocathode. Also, it displayed enduring operational stability for up to 60 h since the firmly wrapped ZIF-8 shells could encapsulate proteins and protect algae from the external stimulation. When coupled with Mo:BiVO4 photoanodes, the PBFC exhibited a remarkable power output of 131.8 μW/cm2 using tetracycline hydrochloride (TCH) as a fuel and an increased degradation rate of TCH. Therefore, this work not only establishs an effective confinement strategy for enzyme to enrich oxygen, but also unveils new possibilities for modified microalgal cells aiding photoelectrocatalytic systems to recover energy from wastewater treatment.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%.