The increasing complexity in morphology and composition of modern biomedical materials (e.g., soft and hard biological tissues, synthetic and natural‐based scaffolds, technical textiles) and the high ...sensitivity to the processing environment requires the development of innovative but benign technologies for processing and treatment. This scenario is particularly applicable where current conventional techniques (steam/dry heat, ethylene oxide, and gamma irradiation) may not be able to preserve the functionality and integrity of the treated material. Sterilization using supercritical carbon dioxide emerges as a green and sustainable technology able to reach the sterility levels required by regulation without altering the original properties of even highly sensitive materials. In this review article, an updated survey of experimental protocols based on supercritical sterilization and of the efficacy results sorted by microbial strains and treated materials was carried out. The application of the supercritical sterilization process in materials used for biomedical, pharmaceutical, and food applications is assessed. The opportunity of supercritical sterilization of not only replace the above mentioned conventional techniques, but also of reach unmet needs for sterilization in highly sensitive materials (e.g., single‐use medical devices, the next‐generation biomaterials, and medical devices and graft tissues) is herein unveiled.
Abstract
Background
COVID-19 has had a disproportionate impact on older adults. Mexico’s population is younger, yet COVID-19’s impact on older adults is comparable to countries with older population ...structures. Here, we aim to identify health and structural determinants that increase susceptibility to COVID-19 in older Mexican adults beyond chronological aging.
Methods
We analyzed confirmed COVID-19 cases in older adults using data from the General Directorate of Epidemiology of Mexican Ministry of Health. We modeled risk factors for increased COVID-19 severity and mortality, using mixed models to incorporate multilevel data concerning healthcare access and marginalization. We also evaluated structural factors and comorbidity profiles compared to chronological age for COVID-19 mortality risk prediction.
Results
We analyzed 20 804 confirmed SARS-CoV-2 cases in adults aged 60 and older. Male sex, smoking, diabetes, and obesity were associated with pneumonia, hospitalization, and intensive care unit (ICU) admission in older adults, CKD and COPD were associated with hospitalization. High social lag indexes and access to private care were predictors of COVID-19 severity and mortality. Age was not a predictor of COVID-19 severity in individuals without comorbidities and combination of structural factors and comorbidities were better predictors of COVID-19 lethality and severity compared to chronological age alone. COVID-19 baseline lethality hazards were heterogeneously distributed across Mexican municipalities, particularly when comparing urban and rural areas.
Conclusions
Structural factors and comorbidity explain excess risk for COVID-19 severity and mortality over chronological age in older Mexican adults. Clinical decision-making related to COVID-19 should focus away from chronological aging onto more a comprehensive geriatric care approach.
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•Vancomycin-loaded chitosan aerogels were prepared for chronic wound management.•Chitosan aerogels exhibited low-density, large surface area and high porosity.•Aerogels can provide a ...fast local administration of vancomycin at the wound site.
Chronic wounds are a prevailing cause of decreased quality of life, being microbial burden a factor hindering the normal wound healing process. Aerogels are nanostructured materials with large surface area (>250 m2/g) and high porosity (>96%). In this work, vancomycin-loaded chitosan aerogel beads were tested as a potential formulation to treat and prevent infections at the wound site. Processing of chitosan in the form of aerogels endowed this polysaccharide with enhanced water sorption capacity and air permeability. The morphological and textural properties of the particles were studied by image and N2 adsorption-desorption analysis and scanning electron microscopy. Vancomycin content and release profiles from aerogel carriers showed a fast drug release that permitted to efficiently achieve local therapeutic levels. Cell studies with fibroblasts and antimicrobial tests against S. aureus showed that the vancomycin-loaded aerogel particles were cytocompatible and effective in preventing high bacterial loads at the wound site.
Helicobacter pylori is the most common cause of gastric cancer (GC), though smoking, alcohol, diet, genetics and epigenetic factors may also have a role in the occurrence of the disease. Why H. ...pylori cause GC in only a minority of those infected remains unknown. Although mechanisms of H. pylori‐induced carcinogenesis are not yet well understood, several genotypes of H. pylori have been associated with strain virulence and disease risk. Primary prevention of GC should be addressed by avoiding exposure to factors that increase the risk and to promote factors associated with decrease risk. Vaccines against H. pylori are an ongoing promise and not yet available. Chemoprevention through vitamin supplementation has shown no benefit. Screening and eradication of H. pylori in the general population is not advised. Given that GC is a multiple‐steps process, the identification of patients with preneoplastic lesions with high risk of progression, and periodic endoscopic surveillance of them represents the most effective way for early diagnosis of GC. However, clinical guidelines for surveillance are lacking and there are no clear criteria to classify patients into high or low risk of progressing to GC. No study has shown the potential usefulness of combining the information on the type of preneoplastic lesions, genetic and epigenetic, lifestyle and virulence bacterial factors in order to identify high risk patients who need more intensive surveillance. The integration of all this information, in a prediction model requires further research and could be the most important contribution for reducing the burden of GC.
Aerogels are a special class of nanostructured materials with very high porosity and tunable physicochemical properties. Although a few types of aerogels have already reached the market in ...construction materials, textiles and aerospace engineering, the full potential of aerogels is still to be assessed for other technology sectors. Based on current efforts to address the material supply chain by a circular economy approach and longevity as well as quality of life with biotechnological methods, environmental and life science applications are two emerging market opportunities where the use of aerogels needs to be further explored and evaluated in a multidisciplinary approach. In this opinion paper, the relevance of the topic is put into context and the corresponding current research efforts on aerogel technology are outlined. Furthermore, key challenges to be solved in order to create materials by design, reproducible process technology and society-centered solutions specifically for the two abovementioned technology sectors are analyzed. Overall, advances in aerogel technology can yield innovative and integrated solutions for environmental and life sciences which in turn can help improve both the welfare of population and to move towards cleaner and smarter supply chain solutions.
Aerogels are the lightest processed solid materials on Earth and with the largest empty volume fraction in their structure. Composition versatility, modularity, and feasibility of industrial scale ...manufacturing are behind the fast emergence of aerogels in the drug delivery field. Compared to other 3D materials, the high porosity (interconnected mesopores) and high specific surface area of aerogels may allow faster loading of small-molecule drugs, less constrained access to inner regions of the matrix, and more efficient interactions of the biological milieu with the polymer matrix. Processing in supercritical CO2 medium for both aerogel production (drying) and drug loading (impregnation) has remarkable advantages such as absence of an oxidizing environment, clean manufacture, and easiness for the scale-up under good manufacturing practices. The aerogel solid skeleton dictates the chemical affinity to the different drugs, which in turn determines the loading efficiency and the release pattern. Aerogels can be used to increase the solubility of BCS Class II and IV drugs because the drug can be deposited in amorphous state onto the large surface area of the skeleton, which facilitates a rapid contact with the body fluids, dissolution, and release. Conversely, tuning the aerogel structure by functionalization with drug-binding moieties or stimuli-responsive components, application of coatings and incorporation of drug-loaded aerogels into other matrices may enable site-specific, stimuli-responsive, or prolonged drug release. The present review deals with last decade advances in aerogels for drug delivery. An special focus is paid first on the loading efficiency of active ingredients and release kinetics under biorelevant conditions. Subsequent sections deal with aerogels intended to address specific therapeutic demands. In addition to oral delivery, the physical properties of the aerogels appear to be very advantageous for mucosal administration routes, such as pulmonary, nasal, or transdermal. A specific section devoted to recent achievements in gene therapy and theranostics is also included. In the last section, scale up strategies and life cycle assessment are comprehensively addressed.
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•Drug solubility in scCO2 and drug-skeleton interactions determine the amount loaded and the drug physical state•Release rate depends on drug crystalline state, drug-skeleton interactions and aerogel hydrophilicity and swelling•Aerogels are suitable for fast, sustained and stimuli-responsive oral drug delivery•The high porosity and specific surface make aerogels appealing for pulmonary, nasal, or transdermal•Gene therapy and theranostics can be accomplished with aerogels
Aerogels are an exceptional group of nanoporous materials with outstanding physicochemical properties. Due to their unique physical, chemical, and mechanical properties, aerogels are recognized as ...promising candidates for diverse applications including, thermal insulation, catalysis, environmental cleaning up, chemical sensors, acoustic transducers, energy storage devices, metal casting molds and water repellant coatings. Here, we have provided a comprehensive overview on the synthesis, processing and drying methods of the mostly investigated types of aerogels used in the biological and biomedical contexts, including silica aerogels, silica-polymer composites, polymeric and biopolymer aerogels. In addition, the very recent challenges on these aerogels with regard to their applicability in biomedical field as well as for personalized medicine applications are considered and explained in detail.
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•An overview on the synthesis of aerogels from various precursors is provided.•Silica, hybrid, and (bio)polymer aerogels are considered as promising biomaterials.•Recent various biomedical applications of aerogels are introduced and elaborated.•Drug delivery and tissue engineering are among the highly studied aerogel applications.•Aerogel properties can be easily tailored for a particular biomedical application.
Metallic Systems Allison, Thomas C; Coskuner, Orkid; Gonzalez, Carlos A
2011
eBook
Metallic systems are ubiquitous in daily life. They play key roles, for example, in the chemistry of many biomolecules, ionic solutions, nanoparticles, and catalytic processes. They may be in solid, ...liquid, or gaseous form. The interactions of other molecules with metal surfaces are of considerable importance. Each of these topics is addressed in M
Cyclodextrins (CDs) are one of the most versatile substances produced by nature, and it is in the aqueous biological environment where the multifaceted potential of CDs can be completely unveiled. ...CDs form inclusion complexes with a variety of guest molecules, including polymers, producing very diverse biocompatible supramolecular structures. Additionally, CDs themselves can trigger cell differentiation to distinct lineages depending on the substituent groups and also promote salt nucleation. These features together with the affinity-driven regulated release of therapeutic molecules, growth factors and gene vectors explain the rising interest for CDs as building blocks in regenerative medicine. Supramolecular poly(pseudo)rotaxane structures and zipper-like assemblies exhibit outstanding viscoelastic properties, performing as syringeable implants. The sharp shear-responsiveness of the supramolecular assemblies is opening new avenues for the design of bioinks for 3D printing and also of electrospun fibers. CDs can also be transformed into polymerizable monomers to prepare alternative nanostructured materials. The aim of this review is to analyze the role that CDs may play in regenerative medicine through the analysis of the last decade research. Most applications of CD-based scaffolds are focussed on non-healing bone fractures, cartilage reparation and skin recovery, but also on even more challenging demands such as neural grafts. For the sake of clarity, main sections of this review are organized according to the architecture of the CD-based scaffolds, mainly syringeable supramolecular hydrogels, 3D printed scaffolds, electrospun fibers, and composites, since the same scaffold type may find application in different tissues.
Cyclodextrins perform as multi-action structural agents of novel 2D and 3D architectures and endow them with unique cell differentiation and mineral nucleation capabilities and reversible hosting of active substances and cell ligands. Display omitted
The increase in the world demand of bone and cartilage replacement therapies urges the development of advanced synthetic scaffolds for regenerative purposes, not only providing mechanical support for ...tissue formation, but also promoting and guiding the tissue growth. Conventional manufacturing techniques have severe restrictions for designing these upgraded scaffolds, namely, regarding the use of organic solvents, shearing forces, and high operating temperatures. In this context, the use of supercritical fluid technology has emerged as an attractive solution to design solvent-free scaffolds and ingredients for scaffolds under mild processing conditions. The state-of-the-art on the technological endeavors for scaffold production using supercritical fluids is presented in this work with a critical review on the key processing parameters as well as the main advantages and limitations of each technique. A special stress is focused on the strategies suitable for the incorporation of bioactive agents (drugs, bioactive glasses, and growth factors) and the in vitro and in vivo performance of supercritical CO2-processed scaffolds.
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