2D Enzyme Cascade Network with Efficient Substrate Channeling by Swinging Arms.

In living cells, compartmentalized or membrane-associated enzymes are often assembled into large networks to cooperatively catalyze cascade reaction pathways essential for cellular metabolism. Here, we report the assembly of an artificial 2D enzyme network of two cascade enzymes-glucose-6-phosphate dehydrogenase (G6PDH) and lactate dehydrogenase (LDH)-on a wireframe DNA origami template. Swinging arms were used to facilitate the transport of the redox intermediate of NAD+ /NADH between enzyme pairs on the array. The assemblies of 2D enzyme networks were characterized by gel electrophoresis and visualized by atomic force microscopy (AFM). The spatial arrangements of multiple enzyme pairs were optimized to facilitate efficient substrate channeling by exploiting the programmability of DNA origami to manipulate the key parameters of swinging arm length and stoichiometry. Compared with a single enzyme pair, the 2D organized enzyme systems exhibited higher reaction efficiency due to the promoted transfer of intermediates within the network.

A Three-Enzyme Pathway with an Optimised Geometric Arrangement to Facilitate Substrate Transfer.

Cascade reactions drive and regulate a variety of metabolic activities. Efficient coupling of substrate transport between enzymes is important for overall pathway activity and also controls the depletion of intermediate molecules that drive the reaction forward. Here, we assembled a three-enzyme pathway on a series of DNA nanoscaffolds to investigate the dependence of their activities on spatial arrangement. Unlike previous studies, the overall activity of the three-enzyme pathway relied less on inter-enzyme distance and more on the geometric patterns that arranged them within a relatively small range of 10-30 nm. Pathway intermediate detection demonstrated that the assembled enzyme systems quickly depleted the intermediate molecules through efficient reaction coupling.

Directional Regulation of Enzyme Pathways through the Control of Substrate Channeling on a DNA Origami Scaffold.

Artificial multi-enzyme systems with precise and dynamic control over the enzyme pathway activity are of great significance in bionanotechnology and synthetic biology. Herein, we exploit a spatially addressable DNA nanoplatform for the directional regulation of two enzyme pathways (G6pDH-MDH and G6pDH-LDH) through the control of NAD(+) substrate channeling by specifically shifting NAD(+) between the two enzyme pairs. We believe that this concept will be useful for the design of regulatory biological circuits for synthetic biology and biomedicine.

An evaluation of electrocoagulation and thermal diffusion following radiofrequency microneedling using an in vivo porcine skin model.

BACKGROUND: Few studies exist that examined the role of radiofrequency microneedling (RFMN) in skin electrocoagulation. This research utilized a porcine model to understand bipolar dermal delivery from an RFMN device. AIMS: The objective of this study was to elucidate and compare the dermal thermal effects of a RFMN device producing 1 and 2 MHz signal amplitudes, with respective voltage and current gradients, utilizing noninsulated and insulated needles by examining the histologic effects on porcine skin. METHODS: Two separate animal studies were conducted to evaluate the electrocoagulation and thermal diffusion effects using the RFMN device. The electrocoagulation effects were assessed histologically using hematoxylin and eosin (H&E) staining, and heating effects were assessed through thermal imaging. RESULTS: Histology results of the thermal injury induced by insulated needles demonstrated that 2 MHz resulted in a narrow and concentrated coagulation zone as compared to 1 MHz. Further, the 1 MHz insulated needle resulted in ovular shaped tissue coagulation as compared to 2 MHz tissue coagulation that was columnar. Finally, full thermal diffusion occurs seconds after the set RF conduction time. CONCLUSION: The findings showed that 1 MHz insulated needle produces larger coagulations with an increase in power level, the 1 MHz noninsulated array was comparable to the 2 MHz insulated array with similar histologic features, and heat dissipates seconds after the set conduction time.

Pilot study: Autologous platelet-rich plasma used in a topical cream for facial rejuvenation.

BACKGROUND: Platelet rich plasma (PRP) is traditionally used as an injectable material for enhanced healing, hair growth, and facial rejuvenation. AIMS: This research examined the novel use of topical autologously sourced PRP added to a preservative cosmetic base and applied twice daily to the face following electroporation for 8 weeks. METHODS: 20 healthy female and male subjects 30-60 years of age were enrolled in this single-site, investigator blinded, vehicle controlled split-face study to evaluate the effect of a PRP-containing serum versus the serum alone on facial photoaging. RESULTS: 90 day stability for the PRP in a preservative serum was achieved with refrigeration at 4 degrees Celsius. Facial skin biopsy histologic findings included improved rete peg architecture. Immunohistochemical analysis showed upregulation for collagen type I with qPCR data demonstrating concomitant upregulation of mRNA for collagen after 8 weeks of topical PRP use. CONCLUSION: These pilot study findings may indicate value for topical PRP in facial rejuvenation.