Search

Microneedles (MN) as a minimally invasive device consisting of a micro-raised array, can penetrate the cuticle to the epidermis and dermis, and which has the advantages of safety, painless, minimally invasive, self-administration and convenience. As a new kind of microneedles, hydrogel microneedles have attracted more attentions in the medical field due to its excellent performance. Hydrogel microneedles have good biocompatibility and mechanical properties, and can be completely removed after skin action without residual polymer in the body. Its unique swelling property can realize minimally invasive extraction of human detection substance and slow release of drugs, which can play a huge role in the field of personal health monitoring and drug controlled release in the future. The mechanism of action, design, preparation and application of hydrogel microneedles were reviewed in this paper, focusing on the current design parameters of hydrogel microneedles and their applications in drug delivery, extraction monitoring and wound healing, and the problems of hydrogel microneedles in skin infection risk, pharmacokinetics and wearing comfort were pointed out. In the future, the key research direction is to combine with intelligent devices to realize both human body monitoring and intelligent drug controlled release on the microneedle patch.

In this paper,using 304 stainless steel material 1 mm in diameter to fuse electron beam deposition rapid prototyping,by controlling the wire feed speed,electronic beam intensity and molding parameters such as the same,choose different forming path was 180 mm × 40 mm × 20 mm of print samples,after tensile test,Its microstructure and mechanical properties were observed and studied. By electron beam additive manufacturing,dense block material without macroscopic defects can be obtained. The average particle size of 304 stainless steel printed is no more than 10 μm,and contains fine uniform precipitation phase. Sample to print,staggered reciprocating print and improved staggered reciprocating print under the path of tensile strength of about 683 MPa,878 MPa,970 MPa,respectively the three print path molding samples can reach the hardness and tensile strength of 515 MPa or requirements,tensile fracture analysis,staggered print mode fracture to ductile fracture,staggered reciprocating type fracture to brittle fracture. The staggered reciprocating printing and the improved staggered reciprocating printing method have better density,better tensile strength and other mechanical properties.

The effect of various structural parameters on the average velocity of the ionic wind pump in the single-needle-ring ionic wind model were studied by numerical simulation combined with orthogonal experimental design, and the optimal structural parameters were obtained. Subsequently, through the array design, the single-needle-ring ion wind was expanded into a large-section ionic wind device. The experimental tests show that the maximum velocity of the developed ionic wind device is 2.55 m/s with the outlet flow rate 1 560.6 L/min and the total power 17.55 W. Its performance is comparable to that of a normal fan. [ABSTRACT FROM AUTHOR]