Multifunctional\nDual Enzyme-Responsive Nanostructured Lipid Carriers for Targeting\nand Enhancing the Treatment of Bacterial Infections

Bacterial infections pose an increasingly\nworrisome threat to the health of humankind, with antibiotic resistance\ncontributing significantly to this burden. With current conventional\nantibiotics perpetuating the problem, and a paucity in developing\nantibiotics, drug delivery systems incorporating nanotechnology appear\npromising. As such, a dual enzyme-responsive multifunctional nanostructured\nlipid carrier (NLC) incorporating farnesol (FAN) and triglycerol monostearate\n(TGMS), was conceptualized for the codelivery of vancomycin (VCM)\nand antimicrobial peptide (AMP) to enhance the antibacterial activity\nof VCM. In silico studies and Microscale Thermophoresis demonstrated\nthe strong binding relationships between the NLC constituents and\ntwo enzymes that exist in higher concentrations during host infection,\nnamely lipase and a matrix metalloproteinase (MMP). The formulated\nnanosystem, VCM-AMP-TF-NLCs, had a particle size, polydispersity index,\nzeta potential, and entrapment efficiency of 149.00 ± 2.97 nm,\n0.07 ± 0.01, −5.51 ± 1.21 mV, and 86.20% ± 1.47%,\nrespectively. The NLCs, which showed stability, and biocompatibility,\nalso demonstrated lipase- and MMP-responsiveness. The in vitro antibacterial\nstudies revealed 2-fold and 8-fold reductions in the minimum inhibitory\nconcentration for the NLCs compared to bare VCM, against methicillin-resistant Staphylococcal aureus (MRSA) and <i>Escherichia coli</i>, respectively. Furthermore,\nin vivo studies revealed that tissues treated with the VCM-AMP-TF-NLCs\ndisplayed significantly reduced bacterial burdens (up to 8.73-fold)\nand less histopathological cellular injury, edema, and necrosis compared\nto the tissues treated with bare VCM alone. The results support the\nsuperiority of the VCM-AMP-TF-NLCs as a multifunctional dual enzyme-responsive\nNLC compared to bare VCM.