User-Tailored Metal–Organic Frameworks as Supports for Carbonic Anhydrase

Carbonic anhydrase (CA) was previously proposed as a green alternative for biomineralization of carbon dioxide (CO2). However, enzyme’s fragile nature when in synthetic environment significantly limits such industrial application. Herein, we hypothesized that CA immobilization onto flexible and hydrated “bridges” that ensure proton-transfer at their interfaces leads to improved activity and kinetic behavior and potentially increases enzyme’s feasibility for industrial implementation. Our hypothesis was formulated considering that water plays a key role in the CO2 hydration process and acts as both the reactant as well as the rate-limiting step of the CO2 capture and transformation process. To demonstrate our hypothesis, two types of user-synthesized organic metallic frameworks [metal–organic frameworks (MOFs), one hydrophilic and one hydrophobic] were considered as model supports and their surface characteristics (i.e., charge, shape, curvature, size, etc.) and influence on the immobilized enzyme’s behavior were evaluated. Morphology, crystallinity and particle size, and surface area of the model supports were determined by scanning electron microscopy, dynamic light scattering, and nitrogen adsorption/desorption measurements, respectively. Enzyme activity, kinetics, and stability at the supports interfaces were determined using spectroscopical analyses. Analysis showed that enzyme functionality is dependent on the support used in the immobilization process, with the enzyme immobilized onto the hydrophilic support retaining 72% activity of the free CA, when compared with that immobilized onto the hydrophobic one that only retained about 28% activity. Both CA–MOF conjugates showed good storage stability relative to the free enzyme in solution, with CA immobilized at the hydrophilic support also revealing increased thermal stability and retention of almost all original enzyme activity even after heating treatment at 70 °C. In contrast, free CA lost almost half of its original activity when subject to the same conditions. This present work suggests that MOFs tunable hydration conditions allow high enzyme activity and stability retention. Such results are expected to impact CO2 storage and transformation strategies based on CA and potentially increase user-integration of enzyme-based green technologies in mitigating global warming

User-Tailored Metal–Organic Frameworks as Supports for Carbonic Anhydrase

Carbonic anhydrase (CA) was previously proposed as a green alternative for biomineralization of carbon dioxide (CO2). However, enzyme’s fragile nature when in synthetic environment significantly limits such industrial application. Herein, we hypothesized that CA immobilization onto flexible and hydrated “bridges” that ensure proton-transfer at their interfaces leads to improved activity and kinetic behavior and potentially increases enzyme’s feasibility for industrial implementation. Our hypothesis was formulated considering that water plays a key role in the CO2 hydration process and acts as both the reactant as well as the rate-limiting step of the CO2 capture and transformation process. To demonstrate our hypothesis, two types of user-synthesized organic metallic frameworks [metal–organic frameworks (MOFs), one hydrophilic and one hydrophobic] were considered as model supports and their surface characteristics (i.e., charge, shape, curvature, size, etc.) and influence on the immobilized enzyme’s behavior were evaluated. Morphology, crystallinity and particle size, and surface area of the model supports were determined by scanning electron microscopy, dynamic light scattering, and nitrogen adsorption/desorption measurements, respectively. Enzyme activity, kinetics, and stability at the supports interfaces were determined using spectroscopical analyses. Analysis showed that enzyme functionality is dependent on the support used in the immobilization process, with the enzyme immobilized onto the hydrophilic support retaining 72% activity of the free CA, when compared with that immobilized onto the hydrophobic one that only retained about 28% activity. Both CA–MOF conjugates showed good storage stability relative to the free enzyme in solution, with CA immobilized at the hydrophilic support also revealing increased thermal stability and retention of almost all original enzyme activity even after heating treatment at 70 °C. In contrast, free CA lost almost half of its original activity when subject to the same conditions. This present work suggests that MOFs tunable hydration conditions allow high enzyme activity and stability retention. Such results are expected to impact CO2 storage and transformation strategies based on CA and potentially increase user-integration of enzyme-based green technologies in mitigating global warming

Additional file 3 of In vitro inflammation and toxicity assessment of pre- and post-incinerated organomodified nanoclays to macrophages using high-throughput screening approaches

Additional file 3: Tables× S1–10 containing particle characterization, secreted cytokine levels, and correlation coefficients

Additional file 2 of In vitro inflammation and toxicity assessment of pre- and post-incinerated organomodified nanoclays to macrophages using high-throughput screening approaches

Additional file 2: Methods for fluorescent high content imaging of macrophage differentiation, differentiation results, and detailed physicochemical analysis results

Additional file 1 of In vitro inflammation and toxicity assessment of pre- and post-incinerated organomodified nanoclays to macrophages using high-throughput screening approaches

Additional file 1: Figures. 1–12 documenting particle characterization, uptake, high-throughput imaging, and protein expression data

Short-Term Pulmonary Toxicity Assessment of Pre- and Post-incinerated Organomodified Nanoclay in Mice

Organomodified nanoclays (ONCs) are increasingly used as filler materials to improve nanocomposite strength, wettability, flammability, and durability. However, pulmonary risks associated with exposure along their chemical lifecycle are unknown. This study’s objective was to compare pre- and post-incinerated forms of uncoated and organomodified nanoclays for potential pulmonary inflammation, toxicity, and systemic blood response. Mice were exposed <i>via</i> aspiration to low (30 μg) and high (300 μg) doses of preincinerated uncoated montmorillonite nanoclay (CloisNa), ONC (Clois30B), their respective incinerated forms (I-CloisNa and I-Clois30B), and crystalline silica (CS). Lung and blood tissues were collected at days 1, 7, and 28 to compare toxicity and inflammation indices. Well-dispersed CloisNa caused a robust inflammatory response characterized by neutrophils, macrophages, and particle-laden granulomas. Alternatively, Clois30B, I-Clois30B, and CS high-dose exposures elicited a low grade, persistent inflammatory response. High-dose Clois30B exposure exhibited moderate increases in lung damage markers and a delayed macrophage recruitment cytokine signature peaking at day 7 followed by a fibrotic tissue signature at day 28, similar to CloisNa. I-CloisNa exhibited acute, transient inflammation with quick recovery. Conversely, high-dose I-Clois30B caused a weak initial inflammatory signal but showed comparable pro-inflammatory signaling to CS at day 28. The data demonstrate that ONC pulmonary toxicity and inflammatory potential relies on coating presence and incineration status in that coated and incinerated nanoclay exhibited less inflammation and granuloma formation than pristine montmorillonite. High doses of both pre- and post-incinerated ONC, with different surface morphologies, may harbor potential pulmonary health hazards over long-term occupational exposures

Short-Term Pulmonary Toxicity Assessment of Pre- and Post-incinerated Organomodified Nanoclay in Mice

Organomodified nanoclays (ONCs) are increasingly used as filler materials to improve nanocomposite strength, wettability, flammability, and durability. However, pulmonary risks associated with exposure along their chemical lifecycle are unknown. This study’s objective was to compare pre- and post-incinerated forms of uncoated and organomodified nanoclays for potential pulmonary inflammation, toxicity, and systemic blood response. Mice were exposed <i>via</i> aspiration to low (30 μg) and high (300 μg) doses of preincinerated uncoated montmorillonite nanoclay (CloisNa), ONC (Clois30B), their respective incinerated forms (I-CloisNa and I-Clois30B), and crystalline silica (CS). Lung and blood tissues were collected at days 1, 7, and 28 to compare toxicity and inflammation indices. Well-dispersed CloisNa caused a robust inflammatory response characterized by neutrophils, macrophages, and particle-laden granulomas. Alternatively, Clois30B, I-Clois30B, and CS high-dose exposures elicited a low grade, persistent inflammatory response. High-dose Clois30B exposure exhibited moderate increases in lung damage markers and a delayed macrophage recruitment cytokine signature peaking at day 7 followed by a fibrotic tissue signature at day 28, similar to CloisNa. I-CloisNa exhibited acute, transient inflammation with quick recovery. Conversely, high-dose I-Clois30B caused a weak initial inflammatory signal but showed comparable pro-inflammatory signaling to CS at day 28. The data demonstrate that ONC pulmonary toxicity and inflammatory potential relies on coating presence and incineration status in that coated and incinerated nanoclay exhibited less inflammation and granuloma formation than pristine montmorillonite. High doses of both pre- and post-incinerated ONC, with different surface morphologies, may harbor potential pulmonary health hazards over long-term occupational exposures