Passivated Porous Silicon Membranes and Their Application to Optical Biosensing

Ferreira, Clara Whyte; Vercauteren, Roselien; Francis, Laurent

doi:10.3390/mi13010010

Cited by 8 publications

(11 citation statements)

References 35 publications

(47 reference statements)

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“…19,35,36 The successful deposition of several metal-oxide layers inside PSi membranes using ALD was already demonstrated previously. 18 In this study, the ALD deposition naturally led to a decrease in pore size and porosity. After the ALD, the stability of the PSiMs was improved.…”

Section: ■ Discussionmentioning

confidence: 79%

“…40,41 Moreover, TiO 2 was also observed to be more hydrophilic than ALD-Al 2 O 3 , 41 which was tested as passivation in a previous study. 18 These hypotheses, while supported by the literature, however remain to be further investigated.…”

Section: ■ Discussionmentioning

confidence: 89%

“…SEM observations of the PSi membranes are depicted in Figure S3. The passivation of PSi membranes using ALD has already been studied previously . It was indeed demonstrated, using both energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, that it is possible to coat the entire depth of PSiMs by lifting the samples up in the deposition chamber.…”

Section: Resultsmentioning

confidence: 99%

“…This sensitivity was much improved compared to previous works, as the LoD is lowered by two orders of magnitude. , This improvement can not only be linked to the upgraded stability and enhanced optical properties but may also be attributed to electrostatic and hydrophilic effects. Indeed, TiO2 is reported as positively charged at physiological pH, while the bacterial lysate is mainly negatively charged. , Moreover, TiO 2 was also observed to be more hydrophilic than ALD-Al 2 O 3 , which was tested as passivation in a previous study . These hypotheses, while supported by the literature, however remain to be further investigated.…”

Section: Discussionmentioning

confidence: 99%

“…The passivation of PSi membranes using ALD has already been studied previously. 18 It was indeed demonstrated, using both energydispersive X-ray spectroscopy and X-ray photoelectron spectroscopy, that it is possible to coat the entire depth of PSiMs by lifting the samples up in the deposition chamber. In the current work, the same technique is used as well, but the porous structure was adapted to account for the pore size reduction after ALD, and higher deposition temperatures were used (e.g., 200 °C).…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Indirect Detection of Bacteria on Optically Enhanced Porous Silicon Membrane-Based Biosensors Using Selective Lytic Enzymes

et al. 2023

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In this work, we developed a biosensor for the indirect detection of bacteria via their lysate. The developed sensor is based on porous silicon membranes, which are known for their many attractive optical and physical properties. Unlike traditional porous silicon biosensors, the selectivity of the bioassay presented in this work does not rely on bio-probes attached to the sensor surface; the selectivity is added to the analyte itself, by the addition of lytic enzymes that target only the desired bacteria. The resulting bacterial lysate is then able to penetrate into the porous silicon membrane and affects its optical properties, while intact bacteria accumulate on top of the sensor. The porous silicon sensors, fabricated using standard microfabrication techniques, are coated with TiO 2 layers using atomic layer deposition. These layers serve as passivation but also enhance the optical properties. The performance of the TiO 2 -coated biosensor is tested for the detection of Bacillus cereus, using the bacteriophage-encoded PlyB221 endolysin as the lytic agent. The sensitivity of the biosensor is much improved compared to previous works, reaching 10 3 CFU/mL, with a total assay time of 1 h 30 min. The selectivity and versatility of the detection platform are also demonstrated, as is the detection of B. cereus in a complex analyte.

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