Guadalupe Gabriel Flores-Rojas

Poly(ethylene terephthalate) (PET) is a versatile polymeric material widely utilized across various sectors, including engineering, food packinging, and medical applications. How-ever, PET inherently lacks the capability to prevent or eliminate microorganism prolifera-tion on its surface and surrounding area. Consequently, endowing PET with anti-infective properties presents a challenge, owing to its inherent properties and chemical structure. Thankfully, several chemical strategies can be deployed to functionalize the surface of PET, enabling the eradication of microorganisms. In this study, PET films underwent functionalization through gamma-ray-induced grafting of poly(N-vinyl caprolactam) (PNVCL). This process facilitated the loading and stabilization of silver nanoparticles (AgNPs) on the grafted PET films and addition provided thermal-responsiveness. Char-acterization of these novel PET-based materials revealed increased surface hydrophilicity without significant alterations in surface morphology or mechanical properties. The an-timicrobial capacity of AgNPs was evaluated against both Gram-positive and Gram-negative bacteria at various temperatures.

Poly(ethylene terephthalate) (PET) is widely used in various sectors due to its biocompatibility, mechanical strength, and chemical stability. However, its inert surface makes it challenging to functionalize and coat with antimicrobial agents to prevent microbial growth and biofilm formation. Therefore, in this work, antimicrobial activity was imparted to PET films using a Cu@Ag nanoparticle coating. The resulting materials were characterized by spectroscopic, thermal, and microscopic techniques, and their mechanical properties and antimicrobial efficacy against S. aureus and E. coli were evaluated. The results demonstrated significant antimicrobial activity and good retention of PET’s mechanical and thermal properties, which are relevant for potential applications in the biomedical and packaging sectors, where infection prevention is crucial.

Poly(ethylene terephthalate) (PET) is widely used in various sectors due to its biocompatibility, mechanical strength, and chemical stability. However, its inert surface makes it challenging to functionalize and coat with antimicrobial agents to prevent microbial growth and biofilm formation. Therefore, in this work, antimicrobial activity was imparted to PET films using a Cu@Ag nanoparticle coating. The resulting materials were characterized by spectroscopic, thermal, and microscopic techniques, and their mechanical properties and antimicrobial efficacy against S. aureus and E. coli were evaluated. The results demonstrated significant antimicrobial activity and good retention of PET’s mechanical and thermal properties, which are relevant for potential applications in the biomedical and packaging sectors, where infection prevention is crucial.

The functionalization of polymeric matrices through graft polymerization offers multiple advantages by introducing new properties through the incorporation of functional chemical groups on the surface. These modifications can change the chemical properties of the matrix, such as hydrophilicity and chemical reactivity, and enable new chemical interactions with other molecules that the matrix alone could not achieve. This expands the applicability of the material in various fields, particularly in medicine, where these functionalized matrices can be employed as drug delivery systems. In this work, poly(N-vinylpyrrolidone) was incorporated through a graft polymerization of N-vinylpyrrolidone on silicone rubber catheters using gamma radiation to promote the polymerization reaction on the matrix. The graft degree of poly(N-vinylpyrrolidone) on the SR matrix was studied based on the absorbed dose and monomer concentration. Additionally, the new materials were characterized using TGA, wettability kinetics, ATR-FTIR, and Raman spectroscopy, as well as a drug loading evaluation.

The functionalization of polymeric matrices through graft polymerization offers various advantages by providing new properties, allowing for additional chemical reactions that the matrix alone could not undergo or that would require drastic chemical conditions to occur. In this work, epoxy groups were incorporated through a graft polymer of poly(glycidyl methacrylate), using a prefunctionalization with peroxide groups in the polytetrafluoroethylene matrix through gamma radiation. These peroxide groups were subsequently used as radical chemical initiators in the graft polymerization reaction of glycidyl methacrylate. The graft polymerization reaction was studied based on the absorbed dose, monomer concentration, reaction time, and temperature. Graphical abstract

Radiation chemistry presents a unique avenue for developing innovative polymeric materials with desirable properties, eliminating the need for chemical initiators, which can be potentially detrimental, especially in sensitive sectors like medicine. In this investigation, we employed a radiation-induced graft polymerization process with N-vinylcaprolactam (NVCL) to modify lignocellulosic membranes derived from Agave salmiana, commonly known as maguey. The membranes underwent thorough characterization employing diverse techniques, including contact angle measurement, degree of swelling, scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier-transform infrared-attenuated total reflectance spectroscopy (FTIR-ATR), nuclear magnetic resonance (CP-MAS ¹³C-NMR), X-ray photoelectron spectroscopy (XPS), and uniaxial tensile mechanical tests. The membranes’ ability to load and release an antimicrobial glycopeptide drug was assessed, revealing significant enhancements in both drug loading and sustained release. The grafting of PNVCL contributed to prolonged sustained release by decreasing the drug release rate at temperatures above the LCST. The release profiles were analyzed using the Higuchi, Peppas–Sahlin, and Korsmeyer–Peppas models, suggesting a Fickian transport mechanism as indicated by the Korsmeyer–Peppas model.

Tissue engineering and regenerative medicine have emerged as innovative approaches to enhance clinical outcomes by addressing tissue lesions and degenerations that can significantly impair organ function. Since human tissues have limited regenerative capacity, the field of regenerative medicine aims to restore damaged tissues and their functionalities. Recent decades have witnessed remarkable progress in materials science, tissue engineering, and medicine, leading to the development of regenerative engineering. This interdisciplinary field has revolutionized the production of artificial matrices, enabling the design of anatomically accurate structures with enhanced biocompatibility, bioabsorption, and cell adhesion. Among the techniques utilized for fabricating cellular scaffolds, the electrospinning of fibers stands out as an ideal approach due to its ability to mimic the characteristics of the extracellular matrix (ECM). Electrospun scaffolds exhibit distinct advantages, including a high surface area-to-volume ratio, exceptional porosity, uniformity, compositional diversity, structural flexibility, and the ease of functionalization with bioactive molecules for controlled release. These versatile properties allow for the creation of nanofiber scaffolds that closely resemble the architecture of the ECM. Consequently, they facilitate the transport of nutrients and oxygen to cells as well as the incorporation of growth factors to stimulate cell growth. These advancements open up a wide range of applications in the field of regenerative medicine.

This work proposes the development of a polymer film made up of affordable components for its use as a healthcare material. Chitosan, itaconic acid, and Randia capitata fruit extract (Mexican variation) are the unique ingredients of this biomaterial prospect. Chitosan (from crustacean chitin) is crosslinked with itaconic acid, and in situ added R. capitata fruit extract in a one-pot reaction carried out in water as the sole solvent. Structurally, the film formed is an ionically crosslinked composite characterized by IR spectroscopy and thermal analysis (DSC and TGA); cell viability was also performed in vitro using fibroblasts BALB/3T3. Dry and swollen films were analyzed to determine affinity and stability in water. This chitosan-based hydrogel is designed as a wound dressing due to the combined properties of the chitosan with R. capitata fruit extract, which has potential as bioactive material due to its properties in epithelial regeneration.

Currently, polyethylene terephthalate (PET) is one of the most widely used polymeric materials in different sectors such as medicine, engineering, and food, among others, due to its benefits, including biocompatibility, mechanical resistance, and tolerance to chemicals and/or abrasion. However, despite all these excellent characteristics, it is not capable of preventing the proliferation of microorganisms on its surface. Therefore, providing this property to PET remains a difficult challenge. Fortunately, different strategies can be applied to remove microorganisms from the PET surface. In this work, the surface of the PET film was functionalized with amino groups and later with a dicarboxylic acid, allowing a grafting reaction with chitosan chains. Finally, the chitosan coating was loaded with silver nanoparticles with an average size of 130 ± 37 nm, presenting these materials with an average cell viability of 80%. The characterization of these new PET-based materials showed considerable changes in surface morphology as well as increased surface hydrophilicity without significantly affecting their mechanical properties. In general, the implemented method can open an alternative pathway to design new PET-based materials due to its good cell viability with possible bacteriostatic activity due to the biocidal properties of silver nanoparticles and chitosan.

Magnetic nanoparticles (MNPs) represent an advanced tool in the medical field because they can be modified according to biomedical approaches and guided by an external magnetic field in the human body. The first objective of this review is to exemplify some promising applications in the medical field, including smart drug-delivery systems, therapies against cancer cells, radiotherapy, improvements in diagnostics using magnetic resonance imaging (MRI), and tissue engineering. Complementarily, the second objective is to illustrate the mechanisms of action and theoretical foundations related to magnetoresponsive materials.