Manipulation of liquid droplets using amphiphilic, magnetic one-dimensional photonic crystal chaperones

Dorvee, Jason R.; Derfus, Austin M.; Bhatia, Sangeeta N.; Sailor, Michael J.

doi:10.1038/nmat1253

Cited by 245 publications

(207 citation statements)

References 22 publications

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“…After etching, the sample was rinsed with ethanol several times and then dried under a stream of nitrogen. Thermal hydrosilylation was accomplished by placing the porous Si sample in liquid 1-dodecene in a Schlenk flask, degassing the liquid with three successive freeze-pump-thaw cycles, and then heating at 140 °C under nitrogen for two hours 25,34 . After removal of the solution, samples were rinsed with ethanol and acetone several times and dried under a stream of nitrogen.…”

Section: Preparation Of Amphiphilic Optically Encoded Porous Silicon mentioning

confidence: 99%

“…34 Adding magnetite to the particles endows them with the ability to be manipulated with magnetic fields, providing a means to direct the motion of liquid droplets in microfluidics applications. 25 In this study, the superparamagnetic properties of the porous Si particles are utilized not only for manipulation but also for heat generation, by application of an alternating electromagnetic field. Thus, each layer of the amphiphilic magnetic particles has its specific function and the preferential location of these layers at the interface between the aqueous droplet and a surrounding organic liquid is of utmost importance.…”

Section: Manipulation and Heating Of Discrete Dropletsmentioning

confidence: 99%

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Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

et al. 2006

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This paper describes a method for local heating of discrete micro-liter scale liquid droplets. The droplets are covered with magnetic porous Si microparticles, and heating is achieved by application of an external alternating electromagnetic field. The magnetic porous Si microparticles consist of two layers: the top layer contains a photonic code and it is hydrophobic, with surfacegrafted dodecyl moieties. The bottom layer consists of a hydrophilic Si oxide host layer that is infused with Fe 3 O 4 nanoparticles. The amphiphilic microparticles spontaneously align at the interface of a water droplet immersed in mineral oil, allowing manipulation of the droplets by application of a magnetic field. Application of an oscillating magnetic field (338 kHz, 18A RMS current in a coil surrounding the experiment) generates heat in the superparamagnetic particles that can raise the temperature of the enclosed water droplet to >80 °C within 5 min.A simple microfluidics application is demonstrated: combining complementary DNA strands contained in separate droplets and then thermally inducing dehybridization of the conjugate. The complementary oligonucleotides were conjugated with the cyanine dye fluorophores Cy3 and Cy5 to quantify the melting/re-binding reaction by fluorescence resonance energy transfer (FRET). The magnetic porous Si microparticles were prepared as photonic crystals, containing spectral codes that allowed the identification of the droplets by reflectivity spectroscopy. The technique demonstrates the feasibility of tagging, manipulating, and heating small volumes of liquids without the use of conventional microfluidic channel and heating systems.

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Section: Preparation Of Amphiphilic Optically Encoded Porous Silicon mentioning

confidence: 99%

Section: Manipulation and Heating Of Discrete Dropletsmentioning

confidence: 99%

Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

et al. 2006

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“…Finally, recent reports have shown that the photonic properties of pSi allow self-reporting of drug loading and release [7,34]. An additional benefit associated with the use of pSi is that it can be processed into films supported on Si, free-standing membranes and micro-or nano-particles [32, [34][35][36][37][38].…”

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confidence: 99%

Controlled Drug Delivery From Composites of Nanostructured Porous Silicon and Poly( L -Lactide)

et al. 2012

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Aims: Porous silicon (pSi) and poly(L-lactide) (PLLA) both display good biocompatibility and tunable degradation behavior, suggesting that composites of both materials are suitable candidates as biomaterials for localized drug delivery into the human body. The combination of a pliable and soft polymeric material with a hard inorganic porous material of high drug loading capacity may engender improved control over degradation and drug release profiles and be beneficial for the preparation of advanced drug delivery devices and biodegradable implants or scaffolds. Materials & methods: In this work, three different pSi and PLLA composite formats were prepared. The first format involved grafting PLLA from pSi films via surface-initiated ring-opening polymerization (pSi–PLLA [grafted]). The second format involved spin coating a PLLA solution onto oxidized pSi films (pSi–PLLA [spin-coated]) and the third format consisted of a melt-cast PLLA monolith containing dispersed pSi microparticles (pSi–PLLA [monoliths]). The surface characterization of these composites was performed via infrared spectroscopy, scanning electron microscopy, atomic force microscopy and water contact angle measurements. The composite materials were loaded with a model cytotoxic drug, camptothecin (CPT). Drug release from the composites was monitored via fluorimetry and the release profiles of CPT showed distinct characteristics for each of the composites studied. Results: In some cases, controlled CPT release was observed for more than 5 days. The PLLA spin coat on pSi and the PLLA monolith containing pSi microparticles both released a CPT payload in accordance with the Higuchi and Ritger–Peppas release models. Composite materials were also brought into contact with human lens epithelial cells to determine the extent of cytotoxicity. Conclusion: We observed that all the CPT containing materials were highly efficient at releasing bioactive CPT, based on the cytotoxicity data. Original submitted 16 December 2010; Revised submitted 29 September 2011; Published online 6 March 2012

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“…18 Magnetic nano-and microparticles have been employed for microfluidic applications, 19 as such particles can be easily manipulated by external magnetic fields from an electromagnet or a permanent magnet. Recently, PSi powders incorporated with magnetic nanoparticles have been used for the manipulation of microliter-scale liquid droplets 20 and for the delivery of nanogram molecular species in fluid. 21 These studies demonstrated the usefulness of magnetic nanoparticle/PSi composites for microfluidic applications.…”

Section: Introductionmentioning

confidence: 99%

Properties of magnetic nickel/porous-silicon composite powders

Nakamura

Adachi

2012

AIP Advances

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The magnetic and photoluminescence (PL) properties of nickel/porous-silicon (Ni/PSi) composite powders are investigated. Ni/PSi composite powders are prepared by stain etching of Si powder in a HF/HNO3 solution followed by electroless plating of Ni nanoparticles on the stain-etched PSi powder in a NiCl2 solution. The Ni/PSi powders exhibit hydrophillicity, superparamagnetism caused by the deposited Ni nanoparticles, and orange-red PL owing to the nanostructured PSi surface. The degree of magnetization decreases with increasing Ni plating time, indicating its dependence on the size of the Ni nanoparticles. The Ni/PSi composite powders also show a stronger magnetization as compared to that of the Ni-particle-plated Si powder. The stronger magnetization results from the larger surface area of PSi. The PL intensity, peak wavelength, and lifetime of Ni/PSi are strongly dependent on the NiCl2 concentration. This dependence is due to the different thickness of the oxide overlayer on the PSi surface formed during the Ni plating process. The existence of the oxide overlayer also results in a small change in the PL intensity against excitation time

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Manipulation of liquid droplets using amphiphilic, magnetic one-dimensional photonic crystal chaperones

Cited by 245 publications

References 22 publications

Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

Local Heating of Discrete Droplets Using Magnetic Porous Silicon-Based Photonic Crystals

Controlled Drug Delivery From Composites of Nanostructured Porous Silicon and Poly( L -Lactide)

Properties of magnetic nickel/porous-silicon composite powders

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