Person:
Colilla Nieto, Montserrat

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First Name
Montserrat
Last Name
Colilla Nieto
URI
https://hdl.handle.net/20.500.14352/77764
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Farmacia
Department
Química en Ciencias Farmacéuticas
Area
Química Inorgánica
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Item Type: Publication × Subject: 615.31 ×

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    Squaraine-loaded mesoporous silica nanoparticles for antimicrobial Photodynamic Therapy against bacterial infection
    (Microporous and Mesoporous Materials, 2024) Melese Dereje, Degnet; García Fontecha, Ana; Pontremoli, Carlotta; González Ortiz, Blanca; Colilla Nieto, Montserrat; Vallet Regí, María Dulce Nombre; Izquierdo Barba, Isabel; Barbero, Nadia
    Antimicrobial photodynamic therapy (aPDT) shows promise as a complementary or alternative approach to conventional antimicrobial treatments. Despite possessing some key advantages, many challenges remain, such as optimizing the delivery of photosensitizers, improving light penetration into tissues, and determining the most effective combinations of photosensitizers and light wavelengths for different infections. Moreover, addressing the challenges associated with the aggregation tendency and poor solubility of some photosensitizers, squaraine dyes (SQs) in particular, is crucial for unlocking their full potential in biomedical applications. This contribution focuses on designing innovative anophotosensitizers with antimicrobial properties using mesoporous silica nanoparticles (MSNs) loaded with a SQ dye (i.e. Br-SQ). MSNs before and after Br-SQ loading were deeply characterized using different techniques, proving the successful incorporation of the dye into the nanocarriers. Upon visible light (640 nm) irradiation, these nanosystems demonstrated remarkable antibacterial activities against both Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). Our results confirmed that MSNs are valuable nanocarriers of hydrophobic photosensitizers, such as Br-SQ, bringing up new opportunities to develop antibiotic-free anoformulations to treat bacterial infection while minimizing the risk of antimicrobial resistance.
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    Poly Lactic-co-Glycolic Acid (PLGA) Loaded with a Squaraine Dye as Photosensitizer for Antimicrobial Photodynamic Therapy
    (Polymers, 2024) Melese Dereje, Degnet; Pontremoli, Carlotta; García Fontecha, Ana; Galliano, Simone; Colilla Nieto, Montserrat; González Ortiz, Blanca; Vallet Regí, María Dulce Nombre; Izquierdo Barba, Isabel; Barbero, Nadia
    Antimicrobial Photodynamic Therapy (aPDT) is an innovative and promising method for combating infections, reducing the risk of antimicrobial resistance compared to traditional antibiotics. Squaraine (SQ) dyes can be considered promising photosensitizers (PSs) but are generally hydrophobic molecules that can self-aggregate under physiological conditions. To overcome these drawbacks, a possible solution is to incorporate SQs inside nanoparticles (NPs). The present work deals with the design and development of innovative nanophotosensitizers based on poly lactic-co-glycolic acid (PLGA) NPs incorporating a brominated squaraine (BrSQ) with potential application in aPDT. Two designs of experiments (DoEs) based on the single emulsion and nanoprecipitation methods were set up to investigate how different variables (type of solvent, solvent ratio, concentration of PLGA, stabilizer and dye, sonication power and time) can affect the size, zeta (ζ)-potential, yield, entrapment efficiency, and drug loading capacity of the SQ-PLGA NPs. SQ-PLGA NPs were characterized by NTA, FE-SEM, and UV-Vis spectroscopy and the ability to produce reactive oxygen species (ROS) was evaluated, proving that ROS generation ability is preserved in SQ-PLGA. In vitro antimicrobial activity against Gram-positive bacteria in planktonic state using Staphylococcus aureus was conducted in different conditions and pH to evaluate the potential of these nanophotosensitizers for aPDT in the local treatment of infections.