Ga(III) can mimic Fe(III) in the biological system due to its similarities in charge and ionic radius to those of Fe(III) and can exhibit antimicrobial activity by disrupting the acquisition and metabolism of Fe in bacterial cells. For example, Ga(NO₃)₃ has been proven to be effective in treating chronic lung infections by Pseudomonas aeruginosa (P. aeruginosa) in cystic fibrosis patients in a recent phase II clinical trial. However, Ga(NO₃)₃ is an ionic compound that can hydrolyze to form insoluble hydroxides at physiological pH, which not only reduces its bioavailability but also causes potential renal toxicity when it is used as a systemic drug. Although complexion with suitable chelating agents has offered a varying degree of success in alleviating the hydrolysis of Ga(III), the use of nanotechnology to deliver this metallic ion should constitute an ultimate solution to all the above-mentioned problems. Thus far, the development of Ga-based nanomaterials as metalloantibiotics is an underexploited area of research. We have developed two different synthetic routes for the preparation of biocompatible Ga₂(HPO₄)₃ NPs and shown that both the PVP- or PEG-coated Ga₂(HPO₄)₃ NPs exhibit potent antimicrobial activity against P. aeruginosa. More importantly, such polymer-coated NPs do not show any sign of Ga-resistant phenotype development after 30 passes, in sharp contrast to Ga(NO₃)_3, which can rapidly develop Ga-resistant phenotypes of P. aeruginosa, indicating the potential of using Ga₂(HPO₄)₃ NPs a new antimicrobial agent in place of Ga(NO₃)₃.

Rhodamine 6G is a hazardous cationic dye whose persistence in water threatens aquatic ecosystems by reducing light penetration and disrupting normal biological activity. Human exposure is also undesirable because it may cause toxic effects involving the skin, eyes, respiratory tract, and internal organs. In this work, novel Ba₂MgB₆O₁₂/Zn₃B₂O₆/Mg₂B₂O₅/BaB₂O₄/C nanocomposites denoted as ZBM500 and ZBM700 were facilely synthesized by the Pechini sol-gel route at 500 and 700 °C for remarkable Rhodamine 6G removal. XRD confirmed the polycrystalline multiphase nature of both samples with average crystallite sizes of 52.5 and 71.3 nm for ZBM500 and ZBM700, respectively. EDX verified the presence of B, C, O, Mg, Zn, and Ba, while FE-SEM and HR-TEM revealed rough flake-like and granular features for ZBM500 and denser lamellar and block-like domains for ZBM700 with average particle sizes of 28.7 and 60.1 nm, respectively. Optimum adsorption occurred at pH 10 using 0.1 g adsorbent at 298 K within 60 min for ZBM500 and 80 min for ZBM700. The maximum adsorption capacities of ZBM500 and ZBM700 reached 432.90 and 320.51 mg/g, respectively. Adsorption was spontaneous, exothermic, predominantly physical, and best interpreted by the pseudo-first-order kinetic equation as well as the Langmuir isotherm. Efficient desorption with 2 M HCl and strong five-cycle reusability confirmed the practical promise of both adsorbents.