Laser fabrication of high aspect ratio thin holes on biodegradable polymer and its application to a microneedle

Aoyagi, Shigeaki; Izumi, Hayato; Isono, Yuichi; Fukuda, Mitsuo; Ogawa, Hiroshi

doi:10.1016/j.sna.2006.11.022

Cited by 103 publications

(59 citation statements)

References 3 publications

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“…No animal studies were conducted here, since this is a Review Article. [25]. OCT images of a 11 x 11 MN array inserted manually by the same volunteer in different materials: neonatal pig skin (C); eight layers of PF (D).…”

Section: Acknowledgmentsmentioning

confidence: 99%

“…MN have been fabricated using a diversity of techniques, mostly from microelectromechanical systems (MEMS) technology. Fabrication techniques range from ion sputtering deposition [22], photolithography [23], wet and dry etching [14], photopolymerisation [24], laser ablation and micromoulding [25,26], layerby-layer deposition [27], droplet-born air blowing [28], and milling [29]. With such a collection of MN types and fabrication techniques, and with most having experienced some degree of success, it is surprising there are still very few MN products on the market.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microneedle characterisation: the need for universal acceptance criteria and GMP specifications when moving towards commercialisation

Lutton

Moore

Larrañeta

et al. 2015

Drug Deliv. and Transl. Res.

110

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Section: Acknowledgmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microneedle characterisation: the need for universal acceptance criteria and GMP specifications when moving towards commercialisation

Lutton

Moore

Larrañeta

et al. 2015

Drug Deliv. and Transl. Res.

110

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“…Polymeric microneedles can be fabricated from novel biocompatible engineering materials such as plastics, biodegradable polymers and water-soluble polymers (e.g., polycarbonate, polyglicolide acid (PGA) and carboxymethylcellulose). Some research groups (Park et al 2005;Aoyagi et al 2007;Yu 2005;Jeong et al 2008) have used polymers as material for microneedle fabrication. Park et al (2005) and Kuo and Yukon (2004) successfully fabricated and characterized polymeric microneedles for various drug delivery applications.…”

Section: Introductionmentioning

confidence: 99%

Structural and microfluidic analysis of hollow side-open polymeric microneedles for transdermal drug delivery applications

Bodhale

Nisar

Afzulpurkar

2009

Microfluid Nanofluid

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In this paper, we present a new design of hollow, out-of-plane polymeric microneedle with cylindrical side-open holes for transdermal drug delivery (TDD) applications. A detailed literature review of existing designs and analysis work on microneedles is first presented to provide a comprehensive reference for researchers working on design and development of micro-electromechanical system (MEMS)-based microneedles and a source for those outside the field who wish to select the best available microneedle design for a specific drug delivery or biomedical application. Then, the performance of the proposed new design of microneedles is numerically characterized in terms of microneedle strength and flow rate at applied inlet pressures. All the previous designs of hollow microneedles have side-open holes in the lumen section with no integrated reservoir on the same chip. We have proposed a new design with side-open holes in the conical section to ensure drug delivery on skin insertion. Furthermore, the present design has an integrated drug reservoir on the back side of the microneedles. Since MEMS-based, hollow, side-open polymeric microneedles with integrated reservoir is a new research area, there is a notable lack of applicable mathematical models to analytically predict structural and fluid flow under various boundary conditions. That is why, finite element (FE) and computational fluid dynamic (CFD) analysis using ANSYS rather than analytical systems has been used to facilitate design optimization before fabrication. The analysis has involved simulation of structural and CFD analysis on three-dimensional model of microneedle array. The effect of axial and transverse loading on the microneedle during skin insertion is investigated in the stress analysis. The analysis predicts that the resultant stresses due to applied bending and axial loads are in the safe range below the yield strength of the material for the proposed design of the microneedles. In CFD analysis, fluid flow rate and pressure drop in the microneedles at applied inlet pressures are numerically and theoretically investigated. The CFD analysis predicts uniform flow through the microneedle array for each microneedle. Theoretical and numerical results for the flow rate and pressure drop are in close agreement with each other, thereby validating the CFD analysis. For the proposed design of microneedles, feasible fabrication techniques such as micro-hot embossing and ultraviolet excimer laser methods are proposed. The results of the present theoretical study provide valuable benchmark and prediction data to fabricate optimized designs of the polymeric, hollow microneedles, which can be successfully integrated with other microfluidic devices for TDD applications.

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“…They bear common features in the mechanism that the drug release pattern is related to the dissolution or degradation of the MN matrix, i.e. the polymer or polysaccharide themselves [30][31][32]. These MNs dissolve or degrade in the skin and thereby leave no sharp medical waste after use [33][34][35].…”

Section: The Advantages Of Hydrogel Mnsmentioning

confidence: 99%

Hydrogel Microneedle Arrays for Transdermal Drug Delivery

Hong

Chen

et al. 2014

Nano-Micro Lett

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Stratum corneum is the main obstacle for drugs to pass through the skin. Microneedles are composed of arrays of micro-projections formed with different materials, generally ranging from 25-2000 μm in height. Microneedles straightly pierce the skin with its short needle arrays to overcome this barrier. Microneedles can be divided into several categories, for instance, solid microneedles, coated microneedles, and hollow microneedles and so on. However, all these types have their weak points related to corresponding mechanisms. In recent years, pioneering scientists have been working on these issues and some possible solutions have been investigated. This article will focus on the microneedle arrays consisting of hydrogels. Hydrogels are commonly used in drug delivery field. Hydrogel microneedles can be further divided into dissolving and degradable microneedles and phase transition microneedles. The former leaves drug with matrix in the skin. The latter has the feature that drugs in the matrix are delivered while the remaining ingredients can be easily removed from the skin after usage. For drugs which are required to be used every day, the phase transition microneedles are more acceptable. This article is written in order to summarize the advantages of these designs and summarize issues to be solved which may hinder the development of this technology.

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Laser fabrication of high aspect ratio thin holes on biodegradable polymer and its application to a microneedle

Cited by 103 publications

References 3 publications

Microneedle characterisation: the need for universal acceptance criteria and GMP specifications when moving towards commercialisation

Microneedle characterisation: the need for universal acceptance criteria and GMP specifications when moving towards commercialisation

Structural and microfluidic analysis of hollow side-open polymeric microneedles for transdermal drug delivery applications

Hydrogel Microneedle Arrays for Transdermal Drug Delivery

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