In-plane single-crystal-silicon microneedles for minimally invasive microfluid systems

Paik, Seung-Joon; Byun, Sung Su; Lim, Jeong Hoon; Park, Yonghwa; Lee, Ahra; Chung, Seok; Chang, Jooyoung; Chun, Kukjin; Cho, Dong‐il Dan

doi:10.1016/j.sna.2003.12.029

Cited by 103 publications

(72 citation statements)

References 17 publications

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“…Different groups have investigated different types of microneedles, from in-plane [10] and out-ofplane [11], to hollow [12], solid [13], macroporous [14], dissolving and swelling [15]. They have been produced from a variety of materials such as glass [16], sugar [17], metal [18], metal coated [19], silicon [14], solid polymer [20], aqueous hydrogel [21] and dissolving polymers [15].…”

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.

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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.

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“…40,41 This technology works best when very deep, narrow access features are used, necessitating micron-scale lithography and high aspect-ratio DRIE. More recently, a variant of the technique has emerged in which isotropic DRIE is used to etch bulk silicon beneath a perforated silicon nitride mask, and CVD then seals the access holes in the mask.…”

Section: Device Design Approachesmentioning

confidence: 99%

A practical guide for the fabrication of microfluidic devices using glass and silicon

Iliescu¹,

Taylor²,

Avram³

et al. 2012

Biomicrofluidics

295

200

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This paper describes the main protocols that are used for fabricating microfluidic devices from glass and silicon. Methods for micropatterning glass and silicon are surveyed, and their limitations are discussed. Bonding methods that can be used for joining these materials are summarized and key process parameters are indicated. The paper also outlines techniques for forming electrical connections between microfluidic devices and external circuits. A framework is proposed for the synthesis of a complete glass/silicon device fabrication flow. I. WHY USE SILICON AND GLASS IN MICRO-AND NANO-FLUIDIC APPLICATIONS?Micro-and nano-fluidic technology continues to be embraced by biologists, 1-3 chemists, 4 and engineers throughout academia and industry. As its applications have expanded, there has been an explosion in the range of materials and processes used to fabricate these devices. The earliest microfluidic devices (e.g., gas 5 and liquid 6 chromatography devices) were made from silicon and glass and borrowed processes directly from semiconductor and microelectromechanical systems (MEMS) manufacturing. 7 Now, however, many researchers have moved away from silicon and glass, and instead use cast elastomers such as polydimethylsiloxane (PDMS)-which is ideal for swift prototyping-or thermoplastic polymers, which can be hot-embossed or injection-molded and are well suited to inexpensive manufacturing. Yet, there remain many applications where glass and silicon offer advantages over polymeric materials. In this paper, we highlight these advantages and offer a framework for selecting fabrication processes when using silicon and glass. A. The dominance of soft lithographyOver the last decade, PDMS has become virtually the default material for forming microfluidic devices, 8 because of the sheer ease with which it can be cast on to a micro-scale mould and then strongly bonded to glass. 9 The elastomeric nature of the material has been exploited to integrate fluidic valves and pumps on-chip and has simplified the production of multi-layer devices because the soft layers readily conform to each other. 10,11 Yet, the low stiffness (usually <1 MPa) of PDMS relative to amorphous thermoplastics, silicon, and glass has its own a) Authors to whom correspondence should be addressed. Electronic addresses: ciliescu@ibn.a-star.edu.sg and hkt@ntu.edu.sg. 6, 016505 (2012) drawbacks. High aspect-ratio channels are notoriously difficult to fabricate in PDMS because of their propensity to collapse. 12 Moreover, difficulties in automating the handling of such a soft material have hampered efforts to scale up PDMS device manufacturing. Meanwhile, PDMS's high oxygen and water permeabilities have proved both a blessing and a curse in different applications.The hydrophobic nature of PDMS can be an important consideration for some biological applications. In drug screening applications, for example, hydrophobic drugs as well as metabolites (urea or albumin) can be absorbed into the device's material due to hydrophobic--hydrophobic interaction...

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“…[48] For in-vitro testing 1% agarose gel was used and for ex-vivo testing, chicken breast flesh, laboratory mouse and an anaesthetized rabbit were used. The Rhodamine B easily penetrated across the 1% agarose gel and chicken breast flesh; the penetration in 1% agarose gel can clearly be viewed in Figure 4.…”

Section: In-vitro and Ex-vivo Testmentioning

confidence: 99%

“…Reproduced with permission from Elsevier. [48] Biological safety test [46] Extraction of chemicals from microneedles was done by immersing microneedles in physiological saline at 37°C for 72 h. The extract was then directly applied on shaved intact human skin for checking dermal irritation. Negative result of the test revealed the biological safety of the microneedles.…”

Section: Transepidermal Water Loss (Tewl)mentioning

confidence: 99%

Microneedles: an emerging transdermal drug delivery system

Bariya

Gohel

Mehta

et al. 2011

Journal of Pharmacy and Pharmacology

313

191

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Objectives One of the thrust areas in drug delivery research is transdermal drug delivery systems (TDDS) due to their characteristic advantages over oral and parenteral drug delivery systems. Researchers have focused their attention on the use of microneedles to overcome the barrier of the stratum corneum. Microneedles deliver the drug into the epidermis without disruption of nerve endings. Recent advances in the development of microneedles are discussed in this review for the benefit of young scientists and to promote research in the area. Key findings Microneedles are fabricated using a microelectromechanical system employing silicon, metals, polymers or polysaccharides. Solid coated microneedles can be used to pierce the superficial skin layer followed by delivery of the drug. Advances in microneedle research led to development of dissolvable/degradable and hollow microneedles to deliver drugs at a higher dose and to engineer drug release. Iontophoresis, sonophoresis and electrophoresis can be used to modify drug delivery when used in concern with hollow microneedles. Microneedles can be used to deliver macromolecules such as insulin, growth hormones, immunobiologicals, proteins and peptides. Microneedles containing 'cosmeceuticals' are currently available to treat acne, pigmentation, scars and wrinkles, as well as for skin tone improvement. Summary Literature survey and patents filled revealed that microneedle-based drug delivery system can be explored as a potential tool for the delivery of a variety of macromolecules that are not effectively delivered by conventional transdermal techniques.

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In-plane single-crystal-silicon microneedles for minimally invasive microfluid systems

Cited by 103 publications

References 17 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

A practical guide for the fabrication of microfluidic devices using glass and silicon

Microneedles: an emerging transdermal drug delivery system

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