Acrylic-Resin-Based Tubular Micromotors Bearing Magnetic Nanoparticles and Enzymes Driven by Visible Light Irradiation: Implications for Accelerating Reactions and Cargo Transport

We present the synthesis of acrylic-resin-based tubular micromotors incorporating layers of magnetite nanoparticles (MNPs) and catalase (Cat) on the inner pore surface (Cat tube micromotors) and investigate their distinctive self-propulsion capabilities modulated by visible light irradiation. In an aqueous H2O2 solution, the Cat tubes demonstrate autonomous movement by expelling O2 bubbles from their opening ends. The propulsion velocity reaches its maximum at the optimal pH and temperature for the Cat enzyme activity. Remarkably, the swimming velocity undergoes rapid acceleration upon exposure to visible light and promptly decelerates upon the cessation of illumination. This phenomenon is ascribed to the photothermal effect induced by the MNPs, elevating the temperature of the adjacent Cat layer and thereby enhancing enzyme activity. The micromotors exhibit recurrent acceleration and deceleration in response to on/off light irradiation, showcasing a high degree of sensitivity and responsiveness

Acrylic-Resin-Based Tubular Micromotors Bearing Magnetic Nanoparticles and Enzymes Driven by Visible Light Irradiation: Implications for Accelerating Reactions and Cargo Transport

We present the synthesis of acrylic-resin-based tubular micromotors incorporating layers of magnetite nanoparticles (MNPs) and catalase (Cat) on the inner pore surface (Cat tube micromotors) and investigate their distinctive self-propulsion capabilities modulated by visible light irradiation. In an aqueous H2O2 solution, the Cat tubes demonstrate autonomous movement by expelling O2 bubbles from their opening ends. The propulsion velocity reaches its maximum at the optimal pH and temperature for the Cat enzyme activity. Remarkably, the swimming velocity undergoes rapid acceleration upon exposure to visible light and promptly decelerates upon the cessation of illumination. This phenomenon is ascribed to the photothermal effect induced by the MNPs, elevating the temperature of the adjacent Cat layer and thereby enhancing enzyme activity. The micromotors exhibit recurrent acceleration and deceleration in response to on/off light irradiation, showcasing a high degree of sensitivity and responsiveness

Acrylic-Resin-Based Tubular Micromotors Bearing Magnetic Nanoparticles and Enzymes Driven by Visible Light Irradiation: Implications for Accelerating Reactions and Cargo Transport

We present the synthesis of acrylic-resin-based tubular micromotors incorporating layers of magnetite nanoparticles (MNPs) and catalase (Cat) on the inner pore surface (Cat tube micromotors) and investigate their distinctive self-propulsion capabilities modulated by visible light irradiation. In an aqueous H2O2 solution, the Cat tubes demonstrate autonomous movement by expelling O2 bubbles from their opening ends. The propulsion velocity reaches its maximum at the optimal pH and temperature for the Cat enzyme activity. Remarkably, the swimming velocity undergoes rapid acceleration upon exposure to visible light and promptly decelerates upon the cessation of illumination. This phenomenon is ascribed to the photothermal effect induced by the MNPs, elevating the temperature of the adjacent Cat layer and thereby enhancing enzyme activity. The micromotors exhibit recurrent acceleration and deceleration in response to on/off light irradiation, showcasing a high degree of sensitivity and responsiveness

Transparent Protein Microtubule Motors with Controllable Velocity and Biodegradability

Slender protein microtube motors with a catalase interior surface are self-propelled in aqueous H₂O₂ by jetting O₂ microbubbles from the open-end terminus. Immobilization of a catalase biocatalyst on the internal wall is achieved using avidin–biotin complexation. It is particularly interesting that the migration of O₂ bubbles in the 1D channel and their subsequent expulsions were clearly visible because the tube walls are transparent. The microtube motor velocity reached a maximum at the optimum pH and temperature of the catalase. Furthermore, the microtubes were digested completely by proteases, showing sufficient biodegradability

O₂^•– scavenging activity (IC₅₀) and H₂O₂ scavenging activity (<i>T</i>₅₀) of HSA-PtNP complex at 25°C.

a<p>In PB solution (pH 7.8, 50 mM).</p>b<p>In PBS solution (pH 7.4), [H₂O₂] = 0.1 mM.</p>c<p>Ref. 29.</p>d<p>Ref. 33. In PB solution (pH 7.8, 45 mM).</p><p>O₂^•– scavenging activity (IC₅₀) and H₂O₂ scavenging activity (<i>T</i>₅₀) of HSA-PtNP complex at 25°C.</p

Crystal structure of HSA (PDB 1E78, ref. 31) and the PtNP binding site.

<p>(A) HSA structure involving the positions of drug site 1 (subdomain IIA, dark green), drug site 2 (subdomain IIIA, dark blue), Cys-34, and Trp-214. Cys-34 and Trp-214 are depicted in space-filling representation. The upper image and lower images respectively show the “front side” and “back side”. (B) Surface electrostatic potential representations of HSA in the same orientations illustrated in (A). Blue and red respectively represent positive charge and negative charge density. Possible binding site of PtNP in the positively charged cleft between subdomain IIA and IIIA is indicated by a yellow circle. These images were produced based on crystal structure coordinates using PyMOL (Schrödinger K. K., CA, USA).</p

Visible absorption spectral data of Hb-HSA<i>₃</i> and Hb-HSA<i>₃</i>(PtNP) clusters in PBS solution (pH 7.4) at 25°C.

a<p>From ref. 20.</p>b<p>HbA (human adult Hb), from ref. 36.</p><p>Visible absorption spectral data of Hb-HSA<i>₃</i> and Hb-HSA<i>₃</i>(PtNP) clusters in PBS solution (pH 7.4) at 25°C.</p

CD spectra of Hb, HSA, and Hb-HSA<i>₃</i>.

<p>[Sample] = 0.2 µM in PBS solution (pH 7.4) at 25°C.</p

Visible absorption spectral changes of Hb-HSA<i>₃</i> cluster.

<p>In PBS solution (pH 7.4) at 25°C.</p

Time course of metHb level of Hb-HSA<i>₃</i> and Hb-HSA<i>₃</i>(PtNP) clusters.

<p>[Hb] = 10 µM in 20 µM H₂O₂ solution at 25°C.</p