SERS Glucose Nanosensing in 3D Tumor Spheroids Without Tissue Damage
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Solution Overview
Problem
Existing methods for continuous and rapid analysis of glucose distribution in three-dimensional tumor models in vitro face challenges due to cytotoxicity, interference with cellular autofluorescence, and tissue damage, limiting precise measurement of glucose concentration.
Innovation Solution
A method involving 4-mercaptophenylboronic acid (4-MPBA)-functionalized silver nanoparticles embedded in a PDMS-based microwell array chip, combined with confocal Raman spectroscopy, to determine glucose concentration in three-dimensional tumor spheroids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external electrochemical-based probes, photothermal optical coherence tomography (PTOCT), or quantum dots are used for sensing glucose in 3D tumor models, then glucose detection capability is achieved, but cytotoxicity, interference with cellular autofluorescence, and tissue damage occur
Solution Approach 1:
The patent uses surface-enhanced Raman spectroscopy (SERS) as an intermediary detection method that avoids direct contact with cellular structures. The SERS technique detects glucose through Raman scattering signals from glucose molecules in the culture medium, eliminating the need for invasive probes that cause cytotoxicity while maintaining high measurement precision for glucose concentration
Solution Approach 2:
The patent replaces mechanical and electromagnetic field-based detection methods (electrochemical probes, photothermal PTOCT) with optical Raman spectroscopy. This substitution eliminates the need for physical probe insertion and strong electromagnetic field application, thereby preventing tissue damage and cytotoxicity while achieving accurate glucose sensing
2Measurement precision
If photothermal or electromagnetic field is applied for glucose sensing, then glucose detection is enabled, but tissue damage occurs
Solution Approach 1:
The patent substitutes photothermal and electromagnetic field-based sensing with Raman spectroscopy, which uses low-intensity laser excitation to generate Raman scattering signals. This optical method detects glucose molecular vibrations without causing thermal damage or electromagnetic field-induced tissue injury, maintaining measurement precision while eliminating harmful effects
3Illumination intensity
If SERS-based nanosensors with large-size linker molecules are used, then Raman signal enhancement is achieved, but glucose molecules are kept away from the nearfield enhancement of the surface, resulting in difficulty to obtain consistent and precise measurement
Solution Approach 1:
The patent changes the key parameter of linker molecule size to achieve optimal performance. By using small-size 4-mercaptophenylboronic acid (4-MPBA) linker molecules instead of large-size linkers, the patent enables glucose molecules to approach the metal surface closely enough to experience strong Raman signal enhancement while maintaining consistent and precise glucose concentration measurements
4Productivity
If continuous in vitro measurement of physiological parameters in 3D culture model is performed, then real-time monitoring capability is achieved, but measurement challenges remain due to technical limitations
Solution Approach 1:
The patent enables continuous measurement of glucose concentration in 3D tumor spheroid cultures by using SERS-based detection of glucose in the culture medium. This method allows repeated sampling and measurement over time without disrupting the 3D culture structure or causing cumulative damage, achieving both continuous monitoring capability and accurate measurement
Solution Approach 2:
The patent uses the culture medium as an intermediary to access glucose information from 3D tumor spheroids. By measuring glucose concentration in the surrounding medium through SERS spectroscopy, the patent continuously monitors tumor metabolism without direct intervention in the 3D structure, maintaining measurement accuracy while enabling long-term continuous observation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous and rapid analysis of glucose distribution in three-dimensional tumor spheroids in vitro, providing precise glucose concentration measurements without cytotoxicity or tissue damage.
Implementation Method 1
surface-enhanced Raman spectroscopy (SERS)-based glucose nanosensor including 4-mercaptophenylboronic acid (4-MPBA)-functionalized silver nanoparticles
Implementation Method 2
subjecting the three-dimensional tumor spheroid to confocal Raman spectroscopy so as to obtain Raman mapping images
Implementation Method 3
4-Mercaptophenylboronic acid (4-MPBA) has been reported to display distinguishable Raman peaks upon binding to plasmonic nanoparticles or metal surface because mercapto group has high affinity to metals
Implementation Method 4
nanostructures, such as silver (Ag) or gold (Au) nanopillars-based substrates, as nanosensors which are capable of enhancing Raman signals by a factor ranging from 106 to 109
Data Source
AI summary
A method for determining glucose concentration in a three-dimensional tumor spheroid in vitro includes: adding a surface-enhanced Raman spectroscopy (SERS)-based glucose nanosensor to a co-culture of cancer cells and stromal cells so as to form a first mixture; adding the first mixture into microwells of a polydimethylsiloxane (PDMS)-based microwell array chip; subjecting the first mixture in the PDMS-based microwell array chip to incubation at 37° C. so as to form the three-dimensional tumor spheroid with the SERS-based glucose nanosensor embedded therein; transferring the three-dimensional tumor spheroid onto a glass slide to allow the three-dimensional tumor spheroid to be mounted thereon; subjecting the three-dimensional tumor spheroid to confocal Raman spectroscopy so as to obtain Raman mapping images of the three-dimensional tumor spheroid; and extracting Raman intensities from the Raman mapping images and mapping the Raman intensities to a calibration curve so as to determine glucose concentration in the three-dimensional tumor spheroid in vitro.