Chitosan-functionalized porous silicon optical transducer for the detection ofcarboxylic acid-containing drugs in water

Sciacca, Beniamino; Secret, Emilie; Pace, Stéphanie; Gonzalez, Philippe; Geobaldo, Francesco; Quignard, Françoise; Cunin, Frédérique

doi:10.1039/c0jm02904a

Cited by 60 publications

(44 citation statements)

References 51 publications

(53 reference statements)

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“…The degradation rate is higher for porous silicon coated by chitosan than for fresh pSi for the first 25 min, but there is a subsequent decrease in the degradation rate of the chitosan-coated sample so that at later times it degrades more slowly than fresh porous silicon, with relative EOT changes of 0.066 and 0.108%/min, respectively. The increased rate of degradation for the chitosan-coated porous silicon sample is in apparent contrast to the previously reported studies of chitosan-coated porous silicon, however, those studies used hydrosilylated porous silicon or oxidized porous silicon [5,23,24]. The increased degradation of pSi-ch compared even to freshly etched porous silicon may be due to the amines present in chitosan, since amines can increase the rate of porous silicon hydrolysis [33,34].…”

Section: Resultsmentioning

confidence: 75%

Monitoring of degradation of porous silicon photonic crystals using digital photography

et al. 2014

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We report the monitoring of porous silicon (pSi) degradation in aqueous solutions using a consumer-grade digital camera. To facilitate optical monitoring, the pSi samples were prepared as one-dimensional photonic crystals (rugate filters) by electrochemical etching of highly doped p-type Si wafers using a periodic etch waveform. Two pSi formulations, representing chemistries relevant for self-reporting drug delivery applications, were tested: freshly etched pSi (fpSi) and fpSi coated with the biodegradable polymer chitosan (pSi-ch). Accelerated degradation of the samples in an ethanol-containing pH 10 aqueous basic buffer was monitored in situ by digital imaging with a consumer-grade digital camera with simultaneous optical reflectance spectrophotometric point measurements. As the nanostructured porous silicon matrix dissolved, a hypsochromic shift in the wavelength of the rugate reflectance peak resulted in visible color changes from red to green. While the H coordinate in the hue, saturation, and value (HSV) color space calculated using the as-acquired photographs was a good monitor of degradation at short times (t < 100 min), it was not a useful monitor of sample degradation at longer times since it was influenced by reflections of the broad spectral output of the lamp as well as from the narrow rugate reflectance band. A monotonic relationship was observed between the wavelength of the rugate reflectance peak and an H parameter value calculated from the average red-green-blue (RGB) values of each image by first independently normalizing each channel (R, G, and B) using their maximum and minimum value over the time course of the degradation process. Spectrophotometric measurements and digital image analysis using this H parameter gave consistent relative stabilities of the samples as fpSi > pSi-ch.

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Section: Resultsmentioning

confidence: 75%

Monitoring of degradation of porous silicon photonic crystals using digital photography

et al. 2014

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“…In these applications, PSi in the form of particles, plays a relevant role as an antitumoral agent,6 as a luminescence emitter,7, 8 or as an active constituent of tissue engineering materials 9. In the form of layers, PSi is an attractive substrate for the development of biosensors10, 11 and cell‐patterning substrates 12…”

Section: Introductionmentioning

confidence: 99%

Soft PVC foams: Study of the gelation, fusion, and foaming processes. II. Adipate, citrate and other types of plasticizers

Zoller

Marcilla

2011

J of Applied Polymer Sci

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Plasticized poly(vinyl chloride) (PVC) is one of the most useful polymeric materials on an industrial scale because of its processability, wide range of obtainable properties, and low cost. PVC plastisols are used in the production of flexible PVC foams. Phthalates are the most used plasticizers for PVC, and in a previous article (part I of this series), we discussed the influence of phthalate ester type plasticizers on the foaming process and on the quality of the foams obtained from the corresponding plastisols. Because the use of phthalate plasticizers has been questioned because of possible health implications, the objective of this work was to undertake a similar study with 11 commercial alternative plasticizers to phthalates. The evolution of the dynamic and extensional viscosity and the interactions and thermal transitions undergone by the plastisols during the heating process were studied. Foams were obtained by rotational molding and were characterized by the determination of their thermomechanical properties, density, and cell size distribution. Correlations were obtained between the molecular weight and structure of the plasticizer and the behavior of the corresponding plastisols. After the characterization of the final foamed product, we concluded that foams of relatively good quality could be prepared with alternative plasticizers for replacing phthalates. Several plasticizers {Mesamoll (alkylsulfonic phenyl ester), Eastman 168 [bis(2-ethylhexyl)-1,4-benzenedicarboxylate], Hexamoll [di(isononyl) cyclohexane-1,2-dicarboxylate], Citroflex A4 acetyl tributyl citrate (ATBC), and Plastomoll (dihexyl adipate)} were found to be interesting alternatives in the production of soft PVC foams because they provided very good quality foams with properties similar to, or even better than, those obtained with phthalate plasticizers.

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“…The porosity of the film was simulated from the reflectance spectra using the transfer matrix method [7,16,21], and oscillated between 68.5% and 78.3%. A thickness of 3,530 nm and pore sizes ranging from 25 to 45 nm in diameter were determined using scanning electron microscopy (data not shown).…”

Section: Resultsmentioning

confidence: 99%

Photonic porous silicon as a pH sensor

et al. 2014

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Chronic wounds do not heal within 3 months, and during the lengthy healing process, the wound is invariably exposed to bacteria, which can colonize the wound bed and form biofilms. This alters the wound metabolism and brings about a change of pH. In this work, porous silicon photonic films were coated with the pH-responsive polymer poly(2-diethylaminoethyl acrylate). We demonstrated that the pH-responsive polymer deposited on the surface of the photonic film acts as a barrier to prevent water from penetrating inside the porous matrix at neutral pH. Moreover, the device demonstrated optical pH sensing capability visible by the unaided eye.

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Chitosan-functionalized porous silicon optical transducer for the detection ofcarboxylic acid-containing drugs in water

Cited by 60 publications

References 51 publications

Monitoring of degradation of porous silicon photonic crystals using digital photography

Monitoring of degradation of porous silicon photonic crystals using digital photography

Soft PVC foams: Study of the gelation, fusion, and foaming processes. II. Adipate, citrate and other types of plasticizers

Photonic porous silicon as a pH sensor

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