The progress of fabrication designs of polymeric microneedles and related biomedical applications

Abstract

Microneedles (MNs) have been broadly used for transdermal delivery of a variety of drugs, ranging from small chemicals to biological macromolecules, due to the properties of increased drug permeability, minimal invasiveness and improved patient compliance. Despite these MNs can be made of different materials, such as metal, silicon, and glass, polymers have attracted the most attention as a microneedle (MN) matrix because of their excellent biocompatibility and biodegradability, which eliminates the requirement of MN removal after drug release. To satisfy different needs of transdermal drug delivery, polymeric MNs have been fabricated with several special designs. In this review, we summarize the advancement of the fabrication designs of polymeric MNs, including integrated MNs, two‐segment MNs, core‐shell or multi‐layered MNs, and arrowhead MNs. The related biomedical applications of MNs with these different specific designs are also discussed. Finally, we provide our perspectives on the future development of polymeric MNs.

Decoding the “Fingerprint” of Implant Materials: Insights into the Foreign Body Reaction

“…From which, poly(caprolactone) (PCL) is the most popular implant material for the fabrication of implantable devices and tissue engineering products, although it can lead to blood protein adsorption and fibrotic encapsulation. [80] As a biodegradable implant material, PCL is compatible to tissues with different stiffness; the good elasticity property offers PCL material many potential application, e.g., PCL fibers, PCL membrane, and PCL particles; and promising immuno-modulatory ability. [81] Using melt electrowriting to produce PCL scaffolds with 40 μm pores was reported to significantly up-regulate the expression of M2 macrophage marker, i.e., CD163, CD206, and IL-10, in human macrophages.…”

Osteogenesis or Apoptosis─Twofold Effects of Zn2+ on Bone Marrow Mesenchymal Stem Cells: An In Vitro and In Vivo Study

“…Conversely, the rate of iron breakdown is too sluggish and the degradation products are stored in the body for an extended duration, which is harmful to tissue regeneration. Zinc degrades at a pace that is halfway between that of magnesium and iron, does not release hydrogen throughout the process, and the body can fully absorb the byproducts. , Besides, zinc ions play a crucial role in the energy metabolism of bone cells and are necessary cofactors for important enzymes connected to bone metabolism, such as collagenase, alkaline phosphatase (ALP), and carbonic anhydrase. , Zinc ions exhibit favorable osteogenic activity by enhancing osteoblast mineralization and proliferation, as well as by encouraging the expression of osteoblast marker genes and the production of collagen by bone marrow mesenchymal stem cells (BMSCs). − Therefore, zinc is a better biodegradable metallic substance than iron and magnesium.…”

“… 6 , 7 Besides, zinc ions play a crucial role in the energy metabolism of bone cells and are necessary cofactors for important enzymes connected to bone metabolism, such as collagenase, alkaline phosphatase (ALP), and carbonic anhydrase. 8 , 9 Zinc ions exhibit favorable osteogenic activity by enhancing osteoblast mineralization and proliferation, as well as by encouraging the expression of osteoblast marker genes and the production of collagen by bone marrow mesenchymal stem cells (BMSCs). 10 − 12 Therefore, zinc is a better biodegradable metallic substance than iron and magnesium.…”