Chem & Bio Engineering最新文献

Hydrogel-based drug delivery systems hold significant clinical potential by enabling precise spatial and temporal control over therapeutic release, ranging from metabolites, macromolecules to other cellular and subcellular constructs. However, achieving programmable release of payloads with diverse molecular weights at distinct rates typically requires complex polymer designs that can compromise the accessibility and biocompatibility of the delivery system. We present a scalable method for producing injectable, micrometer-scale alginate hydrogel particles (microgels) with precisely tuned microstructures for multiplexed, programmable cargo release. Our approach integrates an established jetting technique with a simple postsynthesis ion-exchange process to fine-tune the cross-linked microstructure of alginate microgels. By varying cation type (Ca²⁺, Mg²⁺, Na⁺) and concentration, we systematically modulate the microgels' chemical and physical properties to control release rates of model compounds, including rhodamine B, methylene blue, and dextrans of various molecular weights. Additionally, a PEG-alginate composite microgel system is used to demonstrate the pre-programmed stepwise release of rhodamine B. These findings offer a straightforward strategy for postsynthetic manipulation of ionic microgels with controllable release performances, paving the way for advanced biomedical applications.

Enzymatic catalysis is a green alternative to chemical catalysis, with high activity and selectivity toward the target products in very mild reaction conditions. However, the three-dimensional active structure of an enzyme is very fragile and highly sensitive to external variables such as temperature, pH, and chemical stressors, severely limiting the application range of natural enzymes. A viable solution is to immobilize enzymes within solid porous matrices. Among the most recently developed porous materials are covalent organic frameworks (COFs). They hold great potential as enzyme carriers, as they are nontoxic, light, and highly porous crystalline polymers. Unlike metal–organic frameworks, COFs do not carry a risk of any potential metal-ion leakage, and they offer long-term water/chemical stability. COFs exhibit larger surface areas and variety in their structural/chemical design compared to other conventional supports, like silica or polymers. In this Review, we offer for the first time a comprehensive overview of all the synthetic methods created so far for biocomposites of enzymes and COFs, together with an in-depth discussion of their design principles. We then focus on the critical synthetic parameters that may affect the chemistry of the resultant biocomposites, which find applications in biocatalysis, photoenzymatic catalysis, biosensing, chiral resolution, and stimuli-responsive release. The review ends by discussing the challenges and future opportunities related to the immobilization methods as well as the practical applications. We hope that this Review might guide researchers in developing more advanced encapsulation strategies to boost the enzymatic performance in real-world applications.

MWW zeolites exhibit a distinctive combination of both 10-ring and 12-ring features, making them highly versatile in catalytic applications. When dealing with bulk molecules, the acid sites located on the external surface often serve as the primary active sites, and thus, the distribution of Al sites significantly impacts the active acidity and catalytic performance. In this study, a precise modulation of Al distribution within MWW zeolites was investigated using commercially available N,N,N-trimethyl-1-adamantylammonium hydroxide (TMAdaOH) and cyclohexylamine as organic structure-directing agents (OSDAs). The effects of both OSDAs, along with the synthesis temperature, duration and Na⁺, on the formation of the MWW framework were systematically examined. Advanced solid-state NMR characterization addressed the correlation between Al and organic species. The presence of TMAdaOH showed significant influence on the distributions of cyclohexylamine and T₂ Al sites as well as the benzene transport rate, resulting in MWW zeolites with enriched external surface accessible active acid sites. Owing to these properties, the MWW zeolites exhibited superior catalytic performance compared to conventional MCM-22 zeolites in the cracking of TiPB and alkylation of benzene with cyclohexene. This study highlights the successful synthesis of MWW zeolites using small amounts of low-toxicity OSDAs, offering a scalable and economical approach for the production of zeolites with enhanced catalytic properties for industrial applications.

Highly efficient and energy-conserving membrane separation technology holds vast potential for applications in the bioethanol production process. This work reports a strategy for the fast preparation of an oriented and flexible two-dimensional metal-organic framework (MOF) nanosheet membrane by an electrochemical deposition method. The oriented MOF nanosheet membrane growth, followed by spin-coating of polydimethylsiloxane, resulted in an efficiently formed superhydrophobic and ethanol affinity membrane for separating ethanol from aqueous solution. Vertically aligned MOF nanosheets with strong ethanol affinity and superhydrophobic membrane surfaces simultaneously promote the transport process, thus delivering a relatively high flux of 1.63 kg·m^-2·h^-1 and good separation factor of 14.89 in the pervaporation of 5 wt % ethanol aqueous solution. The oriented arrangement of MOF nanosheets combined with polydimethylsiloxane can significantly enhance the pervaporation selectivity and flux, creating a preferential pathway for the production of biofuel.