The coronavirus disease 2019 (COVID-19) has become a substantial threat to the international health sector and the global economy. As of 26 December 2021, the number of mortalities resulting from COVID-19 exceeded 5.3 million worldwide. The absence of an effective non-vaccine treatment has prompted the quest for prophylactic agents that can be used to combat COVID-19. This study presents the feasibility of chicken egg yolk antibody (IgY) anti-receptor-binding domain (RBD) spike SARS-CoV-2 as a strong candidate to neutralize the virus for application in passive immunization. For the purpose of preclinical studies, we radiolabeled IgY anti-RBD spike SARS-CoV-2 with radionuclide iodine-131. This allowed us to evaluate several biological characteristics of IgY in vitro, in vivo, and ex vivo. The preclinical data suggest that IgY anti-RBD spike SARS-CoV-2 could specifically bind to the SARS-CoV-2 antigens; however, little uptake was observed in normal cells (MRC-5) (<2%). Furthermore, the ex vivo biodistribution study revealed that IgY predominantly accumulated in the trachea of normal mice compared to other organs. We also found that IgY possessed a good safety profile when used as an intranasal agent. Taken together, we propose that IgY anti-RBD spike SARS-CoV-2 has the potential for application in passive immunization against COVID-19.

We synthesised and biologically evaluated two new hybrid probes [¹³¹I]BPF-01 and [¹³¹I]BPF-02 which were built from three structural entities: benzothiazole-phenyl, fluorescein isothiocyanate (FITC), and iodine-131. These probes were designed for potential applications in assisting surgical procedures of solid cancers. The cytotoxicity study demonstrated that fluorescent probes BPF-01 (31.23 μg/mL) and BPF-02 (250 μg/mL) were relatively not toxic to normal immortalized human keratinocytes (HaCaT) cells, as indicated by the percentage of cell survival above 50 %. Furthermore, both probes displayed low to moderate anticancer activity against the breast cancer cells (MDA-MB-231) and prostate cancer cells (LNCaP and DU-145). The probe BPF-01 apparently showed an accumulation in the tumour tissues, as suggested by ex vivo fluorescence examinations. In addition, the cellular uptake study suggests that hybrid probe [¹³¹I]-BPF-01 was potentially accumulated in the MCF-7 cell line with the highest uptake of 16.11 ± 1.52 % after 2 h of incubation, approximately 50-fold higher than the accumulation of iodine-131 (control). The magnetic bead assay suggests that [¹³¹I]-BPF-02 and [¹³¹I]-BPF-02 showed a promising capability to interact with translocator protein 18 kDa (TSPO). Moreover, the computational data showed that the binding scores for ligands 7–8, BPF-01 and BPF-02, and [¹³¹I]-BPF-01 and [¹³¹I]-BPF-02 in the TSPO were considerably high. Accordingly, fluorescent probes BPF-01 and BPF-02, and hybrid probes [¹³¹I]BPF-01 and [¹³¹I]BPF-02 can be further developed for targeting cancer cells during intraoperative tumour surgery.

Hyaluronic acid (HA)-coated nanostructured lipid carriers (NLCs) have emerged as promising inhalable biomaterials for targeted drug delivery to the lungs, yet the interfacial factors governing coating durability and pH-responsive drug release remain poorly understood. In this study, the effect of surfactant molecular structure on HA–surfactant interactions and on the performance of bedaquiline (BDQ)-loaded NLCs was examined by comparing single-chain cetyltrimethylammonium chloride (CTAC) with double-chain dicetyldimonium chloride (DCC). The physicochemical properties, cytotoxicity, macrophage uptake, drug release, storage stability, post-nebulization performance, and molecular interactions of the HA-coated NLCs were analyzed using 200 ns molecular dynamics simulations at pH 7.4 and 5.5. The simulations showed that the equilibrium HA–surfactant interactions were stronger at pH 7.4 than at pH 5.5 for both surfactants, consistent with slower BDQ release under physiological conditions and faster release under acidic conditions. Even though CTAC had more favorable equilibrium HA binding than DCC, the HA-DCC-BDQ NLCs showed better preservation of their surface properties after nebulization, as shown by the consistently negative zeta potentials at all stages of the Andersen Cascade Impactor. The results indicate that coating retention during aerosolization is influenced not only by the equilibrium HA–surfactant interactions but also by the structural arrangement of the surfactant layer. Both HA-coated formulations had acceptable aerosolization performance (MMAD 4.02–4.29 µm; respirable fraction >85%) and remained physicochemically stable for 90 days at 4 °C. The findings thus confirm that HA–surfactant interactions and the surfactant's molecular structure are important interfacial factors governing pH-dependent BDQ release and HA coating retention in inhalable NLCs.

Various separation techniques for separation of technetium-99m (^99mTc) from molybdenum-99 (⁹⁹Mo) are being developed to overcome the drawbacks of using ⁹⁹Mo from neutron activation technique. Ionic liquids (ILs) were used in many extraction processes in metal separation due to their high selectivity. In this research, two benzotriazolium-based ionic liquids were used as co-extractant in ^99mTc/ Mo separation process via liquid-liquid extraction. 1-octyl-3-methyl-benzotriazolium iodide ([MeOcBtu]I) and 1-octyl-3-methyl-benzotriazolium bis (trifluoromethanesulfonyl) imide ([MeOcBtu]TF₂N) were successfully synthesized and analyzed by FTIR, ¹H-NMR and ¹³C-NMR. Extraction processes were conducted in various organic solvents, pH, and extraction time without/ with ionic liquids addition. The data of ratio between ^99mTc distribution coefficient compared to Mo distribution coefficient showed that the addition of ionic liquids exhibited significant improvement of separation factor. The separation factor of extraction using conventional water immiscible solvent ranged between 0 – 8 and increased to 30 – 600 as ILs were added. The optimum conditions which achieved highest separation factor were pH 14 using [MeOcBtu]I-chloroform. Benzotriazolium-based ionic liquid potential to be developed as extractant in the separation of ^99mTc from ⁹⁹Mo.   Keywords: Ionic liquids, benzotriazolium, technetium-99m, molybdenum, liquid-liquid extraction.