Browsing by Author "Santos, Ana L."

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    Light-activated molecular machines are fast-acting broad-spectrum antibacterials that target the membrane
    (AAAS, 2022) Santos, Ana L.; Liu, Dongdong; Reed, Anna K.; Wyderka, Aaron M.; van Venrooy, Alexis; Li, John T.; Li, Victor D.; Misiura, Mikita; Samoylova, Olga; Beckham, Jacob L.; Ayala-Orozco, Ciceron; Kolomeisky, Anatoly B.; Alemany, Lawrence B.; Oliver, Antonio; Tegos, George P.; Tour, James M.; Smalley-Curl Institute; NanoCarbon Center; Welch Institute for Advanced Materials
    The increasing occurrence of antibiotic-resistant bacteria and the dwindling antibiotic research and development pipeline have created a pressing global health crisis. Here, we report the discovery of a distinctive antibacterial therapy that uses visible (405 nanometers) light-activated synthetic molecular machines (MMs) to kill Gram-negative and Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus, in minutes, vastly outpacing conventional antibiotics. MMs also rapidly eliminate persister cells and established bacterial biofilms. The antibacterial mode of action of MMs involves physical disruption of the membrane. In addition, by permeabilizing the membrane, MMs at sublethal doses potentiate the action of conventional antibiotics. Repeated exposure to antibacterial MMs is not accompanied by resistance development. Finally, therapeutic doses of MMs mitigate mortality associated with bacterial infection in an in vivo model of burn wound infection. Visible light–activated MMs represent an unconventional antibacterial mode of action by mechanical disruption at the molecular scale, not existent in nature and to which resistance development is unlikely.
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    Visible-Light-Activated Molecular Machines Kill Fungi by Necrosis Following Mitochondrial Dysfunction and Calcium Overload
    (Wiley, 2023) Santos, Ana L.; Beckham, Jacob L.; Liu, Dongdong; Li, Gang; van Venrooy, Alexis; Oliver, Antonio; Tegos, George P.; Tour, James M.; Smalley-Curl Institute; NanoCarbon Center; Welch Institute for Advanced Materials
    Invasive fungal infections are a growing public health threat. As fungi become increasingly resistant to existing drugs, new antifungals are urgently needed. Here, it is reported that 405-nm-visible-light-activated synthetic molecular machines (MMs) eliminate planktonic and biofilm fungal populations more effectively than conventional antifungals without resistance development. Mechanism-of-action studies show that MMs bind to fungal mitochondrial phospholipids. Upon visible light activation, rapid unidirectional drilling of MMs at ≈3 million cycles per second (MHz) results in mitochondrial dysfunction, calcium overload, and ultimately necrosis. Besides their direct antifungal effect, MMs synergize with conventional antifungals by impairing the activity of energy-dependent efflux pumps. Finally, MMs potentiate standard antifungals both in vivo and in an ex vivo porcine model of onychomycosis, reducing the fungal burden associated with infection.