posted on 2021-08-05, 03:03authored byVarsha Karunakaran, Valliamma N. Saritha, Adukkadan N. Ramya, Vishnu Priya Murali, Kozhiparambil G. Raghu, Kunjuraman Sujathan, Kaustabh Kumar Maiti
Ultrasensitive
detection of cancer biomarkers via single-cell analysis
through Raman imaging is an impending approach that modulates the
possibility of early diagnosis. Cervical cancer is one such type that
can be monitored for a sufficiently long period toward invasive cancer
phenotype. Herein, we report a surface-enhanced Raman scattering (SERS)
nanotag (SERS-tag) for the simultaneous detection of p16/K-i67, a
dual biomarker persisting in the progression of squamous cell carcinoma
of human cervix. A nanoflower-shaped SERS-tag, constituted of hybrid
gold nanostar with silver tips to achieve maximum fingerprint enhancement
from the incorporated reporter molecule, was further functionalized
with the cocktail monoclonal antibodies against p16/K-i67. The recognition
by the SERS-tag was first validated in cervical squamous cell carcinoma
cell line SiHa as a foot-step study and subsequently implemented to
different grades of clinically confirmed exfoliated cells including
normal cell (NC), high-grade intra-epithelial lesion (HC), and squamous
cell carcinoma (CC) samples of the cervix. Precise Raman mapped images
were constituted based on the average intensity gradient of the signature
Raman peaks arising from different grades of exfoliated cells. We
observed a distinct intensity hike of around 10-fold in the single
dysplastic HC and CC samples in comparison to NC specimen, which clearly
justify the prevalence of p16/Ki-67. The synthesized probe is able
to map the abnormal cells within 20 min with high reproducibility
and stability for 1 mm × 1 mm mapping area with good contrast.
Amidst the challenges in Raman image-guided modality, the technique
was further complemented with the gold standard immunocytochemistry
(ICC) dual staining analysis. Even though both are time-consuming
techniques, tedious steps can be avoided and real-time readout can
be achieved using the SERS mapping unlike immunocytochemistry technique.
Therefore, the newly developed Raman image-guided SERS imaging emphasizes
the approach of uplifting of SERS in practical utility with further
improvement for clinical applications for cervical cancer detection
in future.