Publications by authors named "Sumith Ranil Wickramasinghe"

In the rapidly advancing realms of gene therapy and biotechnology, the efficient purification of viral vectors is pivotal for ensuring the safety and efficacy of gene therapies. This study focuses on optimizing membrane selection for viral vector purification by evaluating key properties, including porosity, thickness, pore structure, and hydrophilicity. Notably, we employed adeno-associated virus (AAV)-sized nanoparticles (20 nm), 200 nm particles, and bovine serum albumin (BSA) to model viral vector harvesting.

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In pursuit of sustainability, we explored replacing conventional dissolved air floatation (DAF) in poultry processing wastewater (PPW) treatment with a precisely tuned 0.02 µm stainless-steel ultrafiltration (SSUF) membrane. SSUF is a robust, homogenously porous membrane with strong chemical resistance, ease of cleaning, and exceptional resistance to organic fouling.

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Produced water (PW) generated from hydraulic fracturing operations was treated using an integrated electrocoagulation, ultrafiltration, membrane distillation, and crystallization process (EC UF MDC). The aim was to determine the viability of this integrated process for maximizing water recovery. The results obtained here indicate that optimizing the various unit operations could lead to increased recovery of PW.

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Responsive membranes for hydrophobic interaction chromatography have been fabricated by functionalizing poly(N-vinylcaprolactam) (PVCL) ligands on the substrate of electrospun regenerated cellulose nanofibers. Both static and dynamic binding capacities and product recovery were investigated using bovine serum albumin (BSA) and Immunoglobulin G (IgG) as model proteins. The effects of ligand chain length and chain density on static binding capacity were also studied.

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Poly(ionic) liquid (PIL) augmented membranes were fabricated through self-polymerization of 2-vinyl pyridine and 4-vinyl pyridine followed by dopamine triggered polymerization and bridging with inert polyamide support. The resulting membranes acquired a positive surface charge with a high degree of hydrophilicity. Fourier transformed Infra-red (FTIR) and Energy dispersive X-ray (EDX) spectroscopic investigation revealed the successful augmentation of PIL surface layer, whereas surface morphology was investigated through scanning electron microscopy (SEM) imaging.

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Mixed-matrix electrospun membranes were developed to investigate ammonium removal from low ammonium concentration wastewaters for the first time. Particles derived from the inexpensive zeolite 13X were successfully incorporated into polyethersulfone (PES) matrices. The fabricated mixed-matrix electrospun membranes demonstrate high ammonium removal capacity reaching over 55 mg/g, more than 2.

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Tangential flow filtration (TFF) has many advantages for bioreactor harvesting, as the permeate could be introduced directly to the subsequent capture step. However, membrane fouling has limited its widespread use. This is particularly problematic given the high cell densities encountered today.

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Purification of biologically-derived therapeutics is a major cost contributor to the production of this rapidly growing class of pharmaceuticals. Monoclonal antibodies comprise a large percentage of these products, therefore new antibody purification tools are needed. Small peptides, as opposed to traditional antibody affinity ligands such as Protein A, may have advantages in stability and production costs.

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Modification of ethyleneechlorotrifluoroethylene (ECTFE) membranes by simple surface oxidation was reported in the present investigation in order to induce thin hydrophilic layer on hydrophobic membrane surface for the treatment of real produced water (PW). FTIR spectra indicates the appearance of hydrophilic functional groups (⁻OH and ⁻COOH) on the membrane surface due to modification, while water contact angle, zeta potential measurement, EDX, XPS analysis confirmed the presence of O functionalized hydrophilic groups on the surface. The effect of modification temperature and the time of surface oxidation on the performance of the resulting membranes were studied systematically, which revealed that induction of optimized hydrophilicity can successfully reduce the organic fouling.

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Classical molecular dynamics (MD) simulations were conducted for PNIPAM in 1 M monovalent alkali chloride salt solutions as well as in 0.5 M divalent Mg(2+) and Ca(2+) chloride salt solutions. It was found that the strength for the direct alkali ion-amide O binding is strongly correlated with the size of the ionic radius.

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The effects of ring substitution on the pK(a) value of benzenesulfonic acid (BSA) were investigated using a combined quantum mechanical and classical approach. Ring substitution with strong electron-withdrawing elements such as F, Cl, and Br is found to enhance the acidity of the BSA. More importantly, ring substitution with -NO(2) groups which form an extended conjugated pi-system with the benzene ring exhibits the strongest enhancement of the acidity.

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