Tuning the Pore Size and Surface Chemistry of Porous Silicon for Immunoassays

Abstract

To use porous silicon as an optical interferometric biosensor, the pores must be sufficiently large to allow easy ingress of reagents and the layer must also display Fabry-Perot optical cavity modes. Here the detection antibody is rabbit IgG and the analyte is a-rabbit IgG conjugated to horseradish peroxidase (HRP). For this model system, the pores should be >50 nm in diameter. Such diameters have been obtained in 0.05 W cm n-type silicon using anodisation followed by chemical etching in ethanolic KOH and also by anodising 0.005 W cm p-type material. The latter also displays optical cavity modes. The silicon surface is oxidised in ozone, silanised using aminopropylmethoxysilanes with one, two or three methoxy groups, and cross linked to IgG using glutaraldehyde. High specific binding is found for mono-, di-and tri-methoxy silanes, but the lowest nonspecific binding is found for silanisation with the tri-methoxy silane.

Porous silicon in drug delivery devices and materials☆

“…(4) Slow oxidation of the porous Si surface by dimethyl sulfoxide (DMSO), when coupled with dissolution of the newly formed oxide by HF, is a mild means to enlarge the pores in porous Si films [16]. Aqueous solutions of bases such as KOH can also be used to enlarge the pores after etching [76]. Electrochemical oxidation, in which a porous Si sample is anodized in the presence of a mineral acid such as H 2 SO 4 , yields a fairly stable oxide [77].…”

“…The oxides of porous Si are easy to functionalize using conventional silanol chemistries [76,110,113]. When small pores are present (as with p-type samples), monoalkoxydimethylsilanes (RO-Si(Me) 2 -R′) can be more effective than trialkoxysilanes ((RO) 3 Si-R′) as surface linkers [113].…”

Пористый Кремний Как Наноматериал Для Дисперсных Транспортных Систем Направленной Лекарственной Доставки Ко Внутреннему Уху

“…Подчеркнем, что свойства, приобретаемые выбором исходного материала и технологических условий по-лучения, выделяют пористый кремний в особый класс наноматериалов с возможностью произвольной регу-ляции оптических, электрофизических, каталитических, химических параметров [1,[12][13][14][15][16][17][18]. Так, выбором типа и уровня легирования монокристаллического кремния достигается возможность получать поверхность с раз-личным химическим составом и электронными свойства-ми [12,13].…”

“…От пористости и размера частицы зависит ее " грузовая емкость". От характеристик тек-стуры пористого кремния (микро-, мезо-, макро-или смешанный тип) будут зависеть эффекты старения мате-риала [15,16], которые напрямую определяют интенсив-ность процессов биодеградации in vivo. Произвольно из-меняя удельную площадь поверхности пористых частиц, возможно контролировать скорость высвобождения ЛВ в организме (достигать пролонгированного действия или наоборот сокращать его).…”

New concepts of integrated photonic biosensors based on porous silicon

“…Mesopores (with 2-50 nm diameter) are the most suitable for biosensing, because they are large enough to allow for good biomolecule diffusion and they yield large specific surfaces ranging from 100 m 2 /g to 350 m 2 /g, which strongly increases the amount of biomolecules that can be immobilized on the transducer compared to a 2D surface immobilization. It is worthwhile to point out that the accessibility of the probes by the target molecules (to be detected) depends both on the pore size and on the surface energy of PSi (Tinsley-Bown et al, 2000).…”