Citation: Cao, F.; Zhao, X.; Lv, X.; Hu,
L.; Jiang, W.; Yang, F.; Chi, L.; Chang,
P.; Xu, C.; Xie, Y. An LSPR Sensor
Integrated with VCSEL and
Microfluidic Chip. Nanomaterials
2022, 12, 2607. https://doi.org/
10.3390/nano12152607
Academic Editor: Deepak Kukkar
Received: 7 July 2022
Accepted: 27 July 2022
Published: 29 July 2022
Publisher’s Note: MDPI stays neutral
with regard to jurisdictional claims in
published maps and institutional affil-
iations.
Copyright: © 2022 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Article
An LSPR Sensor Integrated with VCSEL and Microfluidic Chip
Fang Cao
1,†
, Xupeng Zhao
1,†
, Xiaoqing Lv
2,
*, Liangchen Hu
1
, Wenhui Jiang
1
, Feng Yang
1
, Li Chi
3,
*,
Pengying Chang
1
, Chen Xu
1
and Yiyang Xie
1,
*
1
Key Laboratory of Optoelectronics Technology, Ministry of Education, Beijing University of Technology,
Beijing 100124, China; caofang950318@163.com (F.C.); zhaoxp2311@163.com (X.Z.);
huliangchen163@163.com (L.H.); jiangwenhui1997@163.com (W.J.); yangfengqs@bjut.edu.cn (F.Y.);
pychang@bjut.edu.cn (P.C.); xuchen58@bjut.edu.cn (C.X.)
2
State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductor, Chinese Academy of Sciences,
Beijing 100083, China
3
School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China
* Correspondence: lvxiaoqing284@semi.ac.cn (X.L.); chili@ccmu.edu.cn (L.C.); xieyiyang@bjut.edu.cn (Y.X.);
Tel.: +86-10-67391641-868 (Y.X.)
† These authors contributed equally to this work.
Abstract:
The work introduces a localized surface plasmon resonance (LSPR) sensor chip integrated
with vertical-cavity surface-emitting lasers (VCSELs). Using VCSEL as the light source, the hexagonal
gold nanoparticle array was integrated with anodic aluminum oxide (AAO) as the mask on the
light-emitting end face. The sensitivity sensing test of the refractive index solution was realized,
combined with microfluidic technology. At the same time, the finite-difference time- domain (FDTD)
algorithm was applied to model and simulate the gold nanostructures. The experimental results
showed that the output power of the sensor was related to the refractive index of the sucrose solution.
The maximum sensitivity of the sensor was 1.65
×
10
6
nW/RIU, which gives it great application
potential in the field of biomolecular detection.
Keywords:
sensor; localized surface plasmon resonance (LSPR); VCSEL; microfluidic; anodic
aluminum oxide film
1. Introduction
Biosensors are usually devices for detecting and monitoring chemical substances
and biomolecules, divided into many types according to different sensing methods [
1
].
The optical biosensor is an integrated real-time, fast, and portable sensor [
2
–
4
]. The
optical biosensor detects the changes caused by the interaction between biomolecules
through the optical readout system and converts the relevant information into exportable
information for measurement [5,6]. The most popular optical biosensors use the localized
surface plasmon resonance (LSPR) or surface plasmon resonance (SPR) effect of precious
metals as the sensing principle. The SPR effect has been applied in the sensing field for
nearly 40 years [
7
], and various configurations based on the prism and optical fiber have
also been designed [
8
–
10
]. However, the sensors based on a prism structure have the
problems of large volume and low integration [
11
]. Although the optical fiber sensors have
a small volume and simple design, most optical fiber sensors have difficulty extracting
and detecting samples simultaneously due to their structural characteristics. Therefore, the
above two types of sensors cannot sufficiently realize the synchronization of integration
and detection. Because LSPR can be directly coupled with photons and is easy to excite,
the device for exciting LSPR does not need a prism device as complex as SPR [12].
In recent years, sensors based on the LSPR effect have been widely used in biosensors,
medical diagnosis, catalysis, food detection, and other fields [
13
,
14
]. Especially since 2019,
the widespread COVID-19 pandemic has brought severe illness and death for human beings.
Therefore, it is essential to detect and prevent COVID-19 infection in time. Based on this, our
Nanomaterials 2022, 12, 2607. https://doi.org/10.3390/nano12152607 https://www.mdpi.com/journal/nanomaterials
