ICTP – Grupo de Biomateriales

Chemoselective reaction of methoxyaminomethyl BODIPYs with unprotected carbohydrates: a powerful tool for accessing BODIPY neoglycosides

ICTP4 July, 2024

The neoglycosylation of methoxyaminomethyl-appended BODIPYs with unprotected reducing mono-, di-, and trisaccharides produces, in a regio- and stereoselective manner, cyclic N-glycosyl-N-methoxy–BODIPY conjugates, as a relevant class of neoglycosides that display excellent photophysical characteristics in pure water, even at high dye concentrations. In addition, the cellular uptake of some of the neoglycosylated BODIPYs has been confirmed via fluorescence microscopy, and a BODIPY–acarbose conjugate showed comparable enzymatic inhibitory activity to acarbose for two different α-amylases: A. oryzae α-amylase (AOA) and human salivary α-amylase (HSA).

DOI
https://doi.org/10.1039/D4QO00886C

Europium–tannic acid nanocomplexes devised for bone regeneration under oxidative or inflammatory environments

ICTP3 July, 2024

Europium ions (Eu³⁺) are gaining attention in the field of regenerative medicine due to increasing evidence of their osteogenic properties. However, inflammatory and oxidative environments present in many bone diseases, such as osteoporosis or rheumatoid arthritis, are known to hinder this regenerative process. Herein, we describe a straightforward synthetic procedure to prepare Eu³⁺–tannic acid nanocomplexes (EuTA NCs) with modulable physicochemical characteristics, as well as antioxidant, anti-inflammatory, and osteogenic properties. EuTA NCs were rationally synthesized to present different contents of Eu³⁺ on their structure to evaluate the effect of the cation on the biological properties of the formulations. In all the cases, EuTA NCs were stable in distilled water at physiological pH, had a highly negative surface charge (ζ ≈ −25.4 mV), and controllable size (80 < D_h < 160 nm). In vitro antioxidant tests revealed that Eu³⁺ complexation did not significantly alter the total radical scavenging activity (RSA) of TA but enhanced its ability to scavenge H₂O₂ and ferrous ions, thus improving its overall antioxidant potential. At the cellular level, EuTA NCs reduced the instantaneous toxicity of high concentrations of free TA, resulting in better antioxidant (13.3% increase of RSA vs. TA) and anti-inflammatory responses (17.6% reduction of nitric oxide production vs. TA) on cultures of H₂O₂– and LPS-stimulated macrophages, respectively. Furthermore, the short-term treatment of osteoblasts with EuTA NCs was found to increase their alkaline phosphatase activity and their matrix mineralization capacity. Overall, this simple and tunable platform is a potential candidate to promote bone growth in complex environments by simultaneously targeting multiple pathophysiological mechanisms of disease.

DOI
https://doi.org/10.1039/D4TB00697F

Ti/Ta-based composite polysaccharide scaffolds for guided bone regeneration in total hip arthroplasty

ICTP5 June, 2024

Guided bone regeneration can play an important role in orthopedic applications. This work presents the synthesis and characterization of composite scaffolds based on polysaccharides loaded with microparticles of titanium or tantalum as novel materials proposed for composite systems with promising characteristics for guided bone regeneration. Ti/Ta composite scaffolds were synthesized using chitosan and gellan gum as organic substrates and crosslinked with oxidized dextran resulting in stable inorganic-organic composites. Physico-chemical characterization revealed a uniform distribution of metal nanoparticles within the scaffolds that showed a release of metals lower than 5 %. In vitro biological assays demonstrated that Ta composites exhibit a 2 times higher ALP activity than Ti and a higher capacity to support the full differentiation of human mesenchymal stem cells into osteoblasts. These results highlight their potential for bone regeneration applications.

3729048 {3729048:WNV85RCZ} nature 50 1 1 title 1575

1.
García-Robledo, H. et al. Ti/Ta-based composite polysaccharide scaffolds for guided bone regeneration in total hip arthroplasty. International Journal of Biological Macromolecules 271, 132573 (2024). Cite

Nanofibrous ε-Polycaprolactone Matrices Containing Nano-Hydroxyapatite and Humulus lupulus L. Extract: Physicochemical and Biological Characterization for Oral Applications

ICTP6 May, 2024

Oral bone defects occur as a result of trauma, cancer, infections, periodontal diseases, and caries. Autogenic and allogenic grafts are the gold standard used to treat and regenerate damaged or defective bone segments. However, these materials do not possess the antimicrobial properties necessary to inhibit the invasion of the numerous deleterious pathogens present in the oral microbiota. In the present study, poly(ε-caprolactone) (PCL), nano-hydroxyapatite (nHAp), and a commercial extract of Humulus lupulus L. (hops) were electrospun into polymeric matrices to assess their potential for drug delivery and bone regeneration. The fabricated matrices were analyzed using scanning electron microscopy (SEM), tensile analysis, thermogravimetric analysis (TGA), FTIR assay, and in vitro hydrolytic degradation. The antimicrobial properties were evaluated against the oral pathogens Streptococcus mutans, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans. The cytocompatibility was proved using the MTT assay. SEM analysis established the nanostructured matrices present in the three-dimensional interconnected network. The present research provides new information about the interaction of natural compounds with ceramic and polymeric biomaterials. The hop extract and other natural or synthetic medicinal agents can be effectively loaded into PCL fibers and have the potential to be used in oral applications.

3729048 {3729048:I8RD55BH} nature 50 1 1 title 1554

1.
Valle, H. et al. Nanocarrier of α-Tocopheryl Succinate Based on a Copolymer Derivative of (4,7-dichloroquinolin-2-yl)methanol and Its Cytotoxicity against a Breast Cancer Cell Line. Polymers 15, 4342 (2023). Cite

Nanocarrier of α-Tocopheryl Succinate Based on a Copolymer Derivative of (4,7-dichloroquinolin-2-yl)methanol and Its Cytotoxicity against a Breast Cancer Cell Line

ICTP22 December, 2023

In order to improve the water solubility and, therefore, bioavailability and therapeutic activity of anticancer hydrophobic drug α-tocopherol succinate (α-TOS), in this work, copolymers were synthesized via free radicals from QMES (1-[4,7-dichloroquinolin-2-ylmethyl]-4-methacryloyloxyethyl succinate) and VP (N-vinyl-2-pirrolidone) using different molar ratios, and were used to nanoencapsulate and deliver α-TOS into cancer cells MCF-7. QMES monomer was chosen because the QMES pendant group in the polymer tends to hydrolyze to form free 4,7-dichloro-2-quinolinemethanol (QOH), which also, like α-TOS, exhibit anti-proliferative effects on cancerous cells. From the QMES-VP 30:70 (QMES-30) and 40:60 (QMES-40) copolymers obtained, it was possible to prepare aqueous suspensions of empty nanoparticles (NPs) loaded with α-TOS by nanoprecipitation. The diameter and encapsulation efficiency (%EE) of the QMES-30 NPs loaded with α-TOS were 128.6 nm and 52%; while for the QMES-40 NPs loaded with α-TOS, they were 148.8 nm and 65%. The results of the AlamarBlue assay at 72 h of treatment show that empty QMES-30 NPs (without α-TOS) produced a marked cytotoxic effect on MCF-7 breast cancer cells, corresponding to an IC₅₀ value of 0.043 mg mL⁻¹, and importantly, they did not exhibit cytotoxicity against healthy HUVEC cells. Furthermore, NP-QMES-40 loaded with α-TOS were cytotoxic with an IC₅₀ value of 0.076 mg mL⁻¹, demonstrating a progressive release of α-TOS; however, the latter nanoparticles were also cytotoxic to healthy cells in the range of the assayed concentrations. These results contribute to the search for a new polymeric nanocarrier of QOH, α-TOS or other hydrophobic drugs for the treatment of cancer or others diseases treatable with these drugs.

Facile, fast and green synthesis of a highly porous calcium-syringate bioMOF with intriguing triple bioactivity

ICTP30 March, 2023

A facile, fast and green strategy in ethanol is utilized to prepare a new bioMOF, namely CaSyr-1, with the particular characteristics of full biocompatibility given by using just calcium and syringic acid, the later being a phenolic natural product found in fruits and vegetables, permanent porosity with outstanding surface area >1000 m2g-1, and a micropore diameter of 1.4 nm close to mesopore values. Collectively, these data establish CaSyr-1 as one of the most porous bioMOFs reported to date, with high molecular adsorption capacity. The CaSyr-1 adsorptive behavior is revised here through the reversible adsorption of CO2 and the encapsulation of bioactive ingredients in the structure. Remarkably, CaSyr-1 enables the development of triple therapeutic entities, involving bioactive Ca2+, syringic acid and an impregnated drug.

Ketoprofen-based polymer-drug nanoparticles provide anti-inf lammatory properties to HA/collagen hydrogels

ICTP27 March, 2023

Current limitations of wound dressings for treating chronic wounds require the development of novel approaches. One of these is the immune-centered approach, which aims to restore the pro-regenerative and anti-inflammatory properties of macrophages. Under inflammatory conditions, ketoprofen nanoparticles (KT NP) can reduce pro-inflammatory markers of macrophages and increase anti-inflammatory cytokines. To assess their suitability as part of wound dressings, these NP were combined with hyaluronan (HA)/collagen-based hydro- (HG) and cryogels (CG). Different HA, NP concentrations and loading techniques for NP incorporation were used. The NP release, gel morphology and mechanical properties were studied. Generally, colonialization of the gels with macrophages resulted in high cell viability and proliferation. Furthermore, direct contact of the NP to the cells reduced the level of nitric oxide (NO). The formation of multinucleated cells on the gels was low and further decreased by the NP. For the HG that produced the highest reduction in NO, extended ELISA studies showed reduced levels of the pro-inflammatory markers PGE2, IL-12 p40, TNF-α, and IL-6. Thus, HA/collagen-based gels con-taining KT NP may represent a novel therapeutic approach for treating chronic wounds. Whether effects observed in vitro translate into a favorable profile on skin regeneration in vivo will require rigorous testing.

Antiaging properties of antioxidant photoprotective polymeric nanoparticles loaded with coenzyme-Q10

ICTP13 March, 2023

Skin is the most extensive organ within our body. It is continually subjected to stress factors, among which ultraviolet irradiation, a key factor responsible in skin aging since it leads to reactive oxygen species production. In order to fight against these oxidative species, the human body has an innate robust antioxidant mechanism composed of several different substances, one of which is coenzyme Q10. Its capacity to increase cellular energy production and excellent antioxidant properties have been proved, as well as its antiaging properties being able to attenuate cellular damage induced by ultraviolet irradiation in human dermal fibroblasts. However, its high hydrophobicity and photolability hampers its therapeutic potential. In this context, the objective of this work consists of the preparation of chitosan-rosmarinic acid conjugate-based nanoparticles to encapsulate coenzyme Q10 with high encapsulation efficiencies in order to improve its bioavailability and broaden its therapeutic use in skin applications. Hyaluronic acid coating was performed giving stable nanoparticles at physiological pH with 382 ± 3 nm of hydrodynamic diameter (0.04 ± 0.02 polydispersity) and − 18 ± 3 mV of surface charge. Release kinetics studies showed a maximum of 82 % mass release of coenzyme Q10 after 40 min, and radical scavenger activity assay confirmed the antioxidant character of chitosan-rosmarinic acid nanoparticles. Hyaluronic acid-coated chitosan-rosmarinic acid nanoparticles loaded with coenzyme Q10 were biocompatible in human dermal fibroblasts and exhibited interesting photoprotective properties in ultraviolet irradiated cells. In addition, nanoparticles hindered the production of reactive oxygen species, interleukin-6 and metalloproteinase-1, as well as caspase-9 activation maintaining high viability values upon irradiation of dermal fibroblasts. Overall results envision a great potential of these nanovehicles for application in skin disorders or antiaging treatments.

New Insights into the In Vitro Antioxidant Routes and Osteogenic Properties of Sr/Zn Phytate Compounds

ICTP10 March, 2023

Sr/Zn phytate compounds have been shown interest in biomaterial science, specifically in dental implantology, due to their antimicrobial effects against Streptococcus mutans and their capacity to form bioactive coatings. Phytic acid is a natural chelating compound that shows antioxidant and osteogenic properties that can play an important role in bone remodelling processes affected by oxidative stress environments, such as those produced during infections. The application of non-protein cell-signalling molecules that regulate both bone and ROS homeostasis is a promising strategy for the regeneration of bone tissues affected by oxidative stress processes. In this context, phytic acid (PA) emerged as an excellent option since its antioxidant and osteogenic properties can play an important role in bone remodelling processes. In this study, we explored the antioxidant and osteogenic properties of two metallic PA complexes bearing bioactive cations, i.e., Sr2+ (SrPhy) and Zn2+ (ZnPhy), highlighting the effect of the divalent cations anchored to phytate moieties and their capability to modulate the PA properties. The in vitro features of the complexes were analyzed and compared with those of their precursor PA. The ferrozine/FeCl2 method indicated that SrPhy exhibited a more remarkable ferrous ion affinity than ZnPhy, while the antioxidant activity demonstrated by a DPPH assay showed that only ZnPhy reduced the content of free radicals. Likewise, the antioxidant potential was assessed with RAW264.7 cell cultures. An ROS assay indicated again that ZnPhy was the only one to reduce the ROS content (20%), whereas all phytate compounds inhibited lipid peroxidation following the decreasing order of PA > SrPhy > ZnPhy. The in vitro evaluation of the phytate’s osteogenic ability was performed using hMSC cells. The results showed tailored properties related to the cation bound in each complex. ZnPhy overexpressed ALP activity at 3 and 14 days, and SrPhy significantly increased calcium deposition after 21 days. This study demonstrated that Sr/Zn phytates maintained the antioxidant and osteogenic properties of PA and can be used in bone regenerative therapies involving oxidative environments, such as infected implant coatings and periodontal tissues.

Strontium/zinc phytate-based self-assembled monolayers on titanium surfaces enhance osteogenesis and antibacterial performance in vitro

ICTP10 March, 2023

The accumulation of bacteria over implant surfaces is still the first cause of failure, and the development of antimicrobial surfaces constitutes a first line in implant research. Besides, the durability and mechanical performance of implants, in special in the dental area, are mainly determined by their osseointegration capacity into the maxillofacial bone and the appearance of infections. Consequently, implant osseointegration and infection prophylaxis remain as big challenges to attain so a huge investigation is being developed on the production of bioactive surfaces to achieve improvements in these aspects. In this work we propose the functionalization of titanium surfaces (Ti Cp) with self-assembled monolayers (SAMs) of bioactive organophosphate compounds: phytic acid (Ti-PA) and its metallic phytate derivatives bearing Sr2+ and/or Zn2+ (Ti-SrPhy, Ti-ZnPhy and Ti-SrPhy/ZnPhy) which exhibited tunable in vitro osteogenic, antimicrobial and antioxidant properties in a previous work. Thus, phytate compounds are chemically anchored onto Ti discs through a simple procedure consisting of a condensation reaction promoted by heat treatment. EDS and XPS spectroscopies confirm the obtaining of the modified surfaces and the topographic properties and wettability analysed by SEM, AFM, profilometry and contact angle measurements, respectively, are explored. Additionally, phytate-SAMs do not release any cytotoxic compound after 14 days and stimulate in vitro adhesion and proliferation of human osteoblast cells after 14 days of culture. The osteogenic ability of the modified surfaces evaluated by the quantification of ALP activity and matrix mineralization degree shows a significant improvement with respect to unmodified surfaces. Furthermore, the antimicrobial activity of phytate-SAMs against Streptococcus mutans cultures is evaluated. The count of viable cells and the quantification of produced biofilm are significantly reduced by all phytate-SAMs groups (p < 0.001). Cell membrane integrity studies by LIVE/DEAD staining and SEM imaging confirm a decreased viability of adhered bacteria when phytate-based surfaces are tested, due to a disruption in the function and permeability of the cell membrane. Therefore, phytate-SAMs exhibit suitable in vitro features suggesting their promising potential as bioactive coatings of dental implants.