Topical Nanoliposomal Collagen Delivery for Targeted Fibril Formation by Electrical Stimulation.

Collagen is a complex, large protein molecule that presents a challenge in delivering it to the skin due to its size and intricate structure. However, conventional collagen delivery methods are either invasive or may affect the protein's structural integrity. This study introduces a novel approach involving the encapsulation of collagen monomers within zwitterionic nanoliposomes, termed Lip-Cols, and the controlled formation of collagen fibrils through electric fields (EF) stimulation. The results reveal the self-assembly process of Lip-Cols through electroporation and a pH gradient change uniquely triggered by EF, leading to the alignment and aggregation of Lip-Cols on the electrode interface. Notably, Lip-Cols exhibit the capability to direct the orientation of collagen fibrils within human dermal fibroblasts. In conjunction with EF, Lip-Cols can deliver collagen into the dermal layer and increase the collagen amount in the skin. The findings provide novel insights into the directed formation of collagen fibrils via electrical stimulation and the potential of Lip-Cols as a non-invasive drug delivery system for anti-aging applications.

Fabrication of a Tailored, Hybrid Extracellular Matrix Composite.

The extracellular matrix (ECM) is a network of connective fibers that supports cells living in their surroundings. Native ECM, generated by the secretory products of each tissue's resident cells, has a unique architecture with different protein composition depending on the tissue. Therefore, it is very difficult to artificially design in vivo architecture in tissue engineering. In this study, a hybrid ECM scaffold from the basic structure of fibroblast-derived cellular ECMs is fabricated by adding major ECM components of fibronectin (FN) and collagen (COL I) externally. It is confirmed that while maintaining the basic structure of the native ECM, major protein components can be regulated. Then, decellularization is performed to prepare hybrid ECM scaffolds with various protein compositions and it is demonstrated that a liver-mimicking fibronectin (FN)-rich hybrid ECM promoted successful settling of H4IIE rat hepatoma cells. The authors believe that their method holds promise for the fabrication of scaffolds that provide a tailored cellular microenvironment for specific organs and serve as novel pathways for the replacement or regeneration of specific organ tissues.

A Simple Route of Printing Explosive Crystalized Micro-Patterns by Using Direct Ink Writing.

The production of energetic crystalized micro-patterns by using one-step printing has become a recent trend in energetic materials engineering. We report a direct ink writing (DIW) approach in which micro-scale energetic composites composed of 1,3,5-trinitro-1,3,5-triazinane (RDX) crystals in selected ink formulations of a cellulose acetate butyrate (CAB) matrix are produced based on a direct phase transformation from organic, solvent-based, all-liquid ink. Using the formulated RDX ink and the DIW method, we printed crystalized RDX micro-patterns of various sizes and shapes on silicon wafers. The crystalized RDX micro-patterns contained single crystals on pristine Si wafers while the micro-patterns containing dendrite crystals were produced on UV-ozone (UVO)-treated Si wafers. The printing method and the formulated all-liquid ink make up a simple route for designing and printing energetic micro-patterns for micro-electromechanical systems.

Quantitatively controllable fluid flows with ballpoint-pen-printed patterns for programmable photo-paper-based microfluidic devices.

Regulating the fluid flow in microfluidic devices enables a wide range of assay protocols for analytical applications. A programmable, photo-paper-based microfluidic device fabricated by using a method of cutting and laminating, followed by printing, is reported. The flow distance of fluid in the photo-paper-based channel was linearly proportional to time. By printing silver nanoparticle (AgNP) and poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene] (PTFE) patterns on the surface of a photo-paper-based channel, we were able to either increase or decrease the fluid flow in the fabricated microfluidic devices, while maintaining the linearity in the flow distance-time relation. In comparison to the speed of fluid flow in a pristine channel, by using hydrophilic AgNP patterns, we were able to increase the speed in the channel by up to 15 times while we were able to slow the speed by a factor of 3 when using hydrophobic PTFE dots. We then further demonstrated a single-step protocol for detecting glucose and a multi-step protocol for detecting methyl paraoxon (MPO) with our methods in photo-paper-based microfluidic devices. This approach can lead to improved fluid handling techniques to achieve a wide range of complex, but programmable, assays without the need for any additional auxiliary devices for automated operation.

Inkjet-Printed Carbon Nanotubes for Fabricating a Spoof Fingerprint on Paper.

A spoof fingerprint was fabricated on paper and applied for a spoofing attack to unlock a smartphone on which a capacitive array of sensors had been embedded with a fingerprint recognition algorithm. Using an inkjet printer with an ink made of carbon nanotubes (CNTs), we printed a spoof fingerprint having an electrical and geometric pattern of ridges and furrows comparable to that of the real fingerprint. With this printed spoof fingerprint, we were able to unlock a smartphone successfully; this was due to the good quality of the printed CNT material, which provided electrical conductivities and structural patterns similar to those of the real fingerprint. This result confirms that inkjet-printing CNTs to fabricate a spoof fingerprint on paper is an easy, simple spoofing route from the real fingerprint and suggests a new method for outputting the physical ridges and furrows on a two-dimensional plane.

Programmable Paper-Based Microfluidic Devices for Biomarker Detections.

Recent advanced paper-based microfluidic devices provide an alternative technology for the detection of biomarkers by using affordable and portable devices for point-of-care testing (POCT). Programmable paper-based microfluidic devices enable a wide range of biomarker detection with high sensitivity and automation for single- and multi-step assays because they provide better control for manipulating fluid samples. In this review, we examine the advances in programmable microfluidics, i.e., paper-based continuous-flow microfluidic (p-CMF) devices and paper-based digital microfluidic (p-DMF) devices, for biomarker detection. First, we discuss the methods used to fabricate these two types of paper-based microfluidic devices and the strategies for programming fluid delivery and for droplet manipulation. Next, we discuss the use of these programmable paper-based devices for the single- and multi-step detection of biomarkers. Finally, we present the current limitations of paper-based microfluidics for biomarker detection and the outlook for their development.