Search for: All records

Enzymes are advanced biocatalysts, while immobilizing enzymes on solid supports, particularly metal–organic frameworks (MOFs), enhances enzyme stability, reusability, and substrate selectivity. One-pot cocrystallization (CC) of enzymes in MOFs in the aqueous phase avoids enzyme size limitation and leaching; our recent CC MOF “library” offers a collection of metal–ligand combinations for customizable enzyme immobilization [ACS Appl. Mater. Interfaces 2022, 14, 46, 51619–51629]. However, CC generally suffers from low yield and stability. Mechanochemical or liquid-assisted grinding (LAG) synthesis overcomes this issue, yet most current approaches use metals, ligands, and enzymes in powder states with organic solvents, limiting eco-friendliness and enzyme compatibility. Water as an eco-friendly LAG synthesis agent (eco-LAGent) offers a greener medium to preserve protein folding states, hydration shells, and conformational flexibility, essential for activity. However, only one MOF has been reported to be synthesized this way. Due to the different metal–ligand contact mechanisms, MOFs by CC or eco-LAGent synthesis may not have the same crystal structures either, yet there is a lack of data to compare. Here, we expand the “library” of enzyme@MOF biocatalysts synthesized in an eco-LAGent, water, using abundant, low-toxicity metal ions and ligands, achieving improved thermal and pH stability and significantly enhanced enzyme@MOF yields while proving the high chance of scaling up and eventually industrial applications. Grinding also impacted the interface of metal–ligand contact─compared to aqueous-phase CC, eco-LAGent synthesis increased the crystallinity in 3 MOFs, generated new MOF structures in another 3, and improved the thermal and pH stability across most resultant enzyme@MOF cocrystals. This study generalizes the eco-LAGent synthesis to more MOFs and opens a new avenue to encapsulate enzymes in high-quality crystals with a customized selection of metal ions and ligands (according to enzymes and applications) under green and scalable conditions. 

A synthetic biomolecular condensate (sBC) was developed using zein, a hydrophobic protein derived from plants. These particles can be used as an artifiical platform to understand the structure and function of natural protein-rich condensates. 

Understanding how substrate structure alters an enzyme's conformational landscape is central to catalyst design. Using single-molecule electronic sensors, we reveal how substitutions on an HDAC8 substrate modulate the enzyme's underlying catalytic dynamics. We demonstrate that a trifluoroacetyl group accelerates catalysis, while a Boc cap and an allosteric activator synergistically simplify the kinetic pathway by stabilizing productive conformations. These findings provide direct, real-time insight into how substrate-induced conformational dynamics control enzyme catalysis. 

Developing protein confinement platforms is an attractive research area that not only promotes protein delivery but also can result in artificial environment mimicking of the cellular one, impacting both the controlled release of proteins and the fundamental protein biophysics. Polymeric nanoparticles (PNPs) are attractive platforms to confine proteins due to their superior biocompatibility, low cytotoxicity, and controllable release under external stimuli. However, loading proteins into PNPs can be challenging due to the potential protein structural perturbation upon contacting the interior of PNPs. In this work, we developed a novel approach to encapsulate proteins in PNPs with the assistance of the zeolitic imidazolate framework (ZIF). Here, ZIF offers an additional protection layer to the target protein by forming the protein@ZIF composite via aqueous-phase cocrystallization. We demonstrated our platform using a model protein, lysozyme, and a widely studied PNP composed of poly(ethylene glycol)-poly(lactic-co-glycolic acid) (PEG–PLGA). A comprehensive study via standard loading and release tests as well as various spectroscopic techniques was carried out on lysozyme loaded onto PEG–PLGA with and without ZIF protection. As compared with the direct protein encapsulation, an additional layer with ZIF prior to loading offered enhanced loading capacity, reduced leaching, especially in the initial stage, led to slower release kinetics, and reduced secondary structural perturbation. Meanwhile, the function, cytotoxicity, and cellular uptake of proteins encapsulated within the ZIF-bound systems are decent. Our results demonstrated the use of ZIF in assisting in protein encapsulation in PNPs and established the basis for developing more sophisticated protein encapsulation platforms using a combination of materials of diverse molecular architectures and disciplines. As such, we anticipate that the protein-encapsulated ZIF systems will serve as future polymer protein confinement and delivery platforms for both fundamental biophysics and biochemistry research and biomedical applications where protein delivery is needed to support therapeutics and/or nutrients. 

Self-assembled materials capable of modulating their assembly properties in response to specific enzymes play a pivotal role in advancing 'intelligent' encapsulation platforms for biotechnological applications. Here, we introduce a previously... 

Robotically assisted painting is widely used for spray and dip applications. However, use of robots for coating substrates using a roller applicator has not been systematically investigated. We showed for the first time, a generic robot arm-supported approach to painting engineering substrates using a roller with a constant force at an accurate joint step, while retaining compliance and thus safety. We optimized the robot design such that it is able to coat the substrate using a roller with a performance equivalent to that of a human applicator. To achieve this, we optimized the force, frequency of adjustment, and position control parameters of robotic design. A framework for autonomous coating is available at https://github.com/duyayun/Vision-and-force-control-automonous-painting-with-rollers; users are only required to provide the boundary coordinates of surfaces to be coated. We found that robotically- and human-painted panels showed similar trends in dry film thickness, coating hardness, flexibility, impact resistance, and microscopic properties. Color profile analysis of the coated panels showed non-significant difference in color scheme and is acceptable for architectural paints. Overall, this work shows the potential of robot-assisted coating strategy using roller applicator. This could be a viable option for hazardous area coating, high-altitude architectural paints, germs sanitization, and accelerated household applications.