Cell
detection is of great significance for biomedical research.
Surface enhanced Raman scattering (SERS) has been widely applied to
the detection of cells. However, there is still a lack of a general,
low-cost, rapid, and sensitive SERS method for cell detection. Herein,
a dynamic liquid SERS platform, which combines label-free SERS technique
with soft tubular microfluidics for cell detection, is proposed. Compared
with common static solid and static liquid measurement, the dynamic
liquid SERS platform can present dynamical mixing, precise control
of the mixing time, and continuous spectra collection. By characterizing
the model molecules, the proposed dynamic liquid SERS platform has
successfully demonstrated good stability and repeatability with 1.90%
and 4.98% relative standard deviation (RSD), respectively. Three cell
lines including one normal breast cell line (MCF-10A) and two breast
cancer cell lines (MCF-7 and MDA-MB-231) were investigated in this
platform. 270 cell spectra were selected as the training set for the
classification of the models based on the K-Nearest Neighbor (K-NN)
algorithm. In three independent experiments, three types of cells
were identified by a test set containing 180 cell spectra with sensitivities
above 83.3% and specificities above 91.6%. The accuracy was 94.1 ±
1.14% among three independent cell identifications. The dynamic liquid
SERS platform has shown higher signal intensity, better repeatability,
less pretreatment, and obtainment of more spectra with less time consumption.
It will be a powerful detection tool in the area of cell research,
clinical diagnosis, and food safety.
Alginate as a good drug delivery vehicle has excellent biocompatibility and biodegradability. In the ionic gelation process between alginate and Ca2+, the violent reaction is the absence of a well-controlled strategy in the synthesizing calcium alginate (CaA) microgels. In this study, a concentration-controlled microfluidic chip with central buffer flow was designed and 3D-printed to well-control the synthesis process of CaA microgels by the diffusion mixing pattern. The diffusion mixing pattern in the microfluidic chip can slow down the ionic gelation process in the central stream. The particle size can be influenced by channel length and flow rate ratio, which can be regulated to 448 nm in length and 235 nm in diameter. The delivery ratio of Doxorubicin (Dox) in CaA microgels are up to 90% based on the central stream strategy. CaA@Dox microgels with pH-dependent release property significantly enhances the cell killing rate against human breast cancer cells (MCF-7). The diffusion mixing pattern gives rise to well-controlled synthesis of CaA microgels, serving as a continuous and controllable production process for advanced drug delivery systems.
Photodynamic
therapy (PDT) and fluorescence imaging offer the possibility
of precise and personalized treatment of cancer, but low singlet oxygen
production of a commercial photosensitizer and the quenching effect
of fluorescent dyes limit the further application of PDT treatment
and fluorescence imaging. In addition, the single nanoplatform that
simultaneously achieved singlet oxygen and fluorescence enhancement
is rare. In this paper, a novel simultaneously enhanced singlet oxygen
and fluorescence production nanoplatform of AuNR@mSiO2–Ce6–Cy5.5
has been successfully designed and synthesized by surface plasmon
resonance coupling. The as-synthesized nanoplatform achieved a 1.8-fold
enhancement of the singlet oxygen production of Ce6 and a 5.0-fold
enhancement of the fluorescence production of Cy5.5 by surface plasmon
resonance coupling. The as-synthesized nanoplatform simultaneously
enhances the photodynamic therapy and fluorescence imaging of cancer,
which will have great potential in biomedical applications.
A “Capillary Force-Driven Stamped” (CFDS) approach is developed for directly printing patterned nanomaterials in aqueous solution, which may be promising for flexible electronics and biomedical analysis.
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