The incorporation of porous silicon (PSi) biosensors into lab-on-a-chip devices presents great promise for sensitive and real-time detection of biological targets, offering signiﬁcant advantages in terms of high throughput, small sample volumes, and rapid operation time.
We design novel microfluidic devices and assays that integrate PSi optical biosensor with electrokinetic techniques (in collaboration with Prof. Moran Bercovici, Technion) for highly sensitive label-free detection.
Recently, we demonstrated a highly-sensitive lab-on-a-chip device for DNA detection. The DNA target molecules are focused using an electric ﬁeld within a ﬁnite and conﬁned zone, and this highly concentrated analyte is delivered to an on-chip PSi Fabry–Pérot optical transducer, pre-functionalized with capture probes. Using reﬂective interferometric Fourier transform spectroscopy real-time monitoring, a 1000-fold improvement in limit of detection (LoD) is demonstrated compared to a standard assay, using the same biosensor.
Thus, a measured limit of detection of 1 × 10 −9 M is achieved without compromising speciﬁcity. To the best of our knowledge this is the lowest LoD measured to date by any PSi biosensor for DNA.
The concepts presented herein can be readily applied to other ionic targets, paving way for the development of other highly sensitive chemical and biochemical assays.
Researchers: Naama Massad-Ivanir and Sofi Arshavski