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| | [111] | [112] | [113] | [5] | [114] |
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| Technique | Phase-shifting laser microscopy (PLM) | Atomic force microscopy (AFM) | Gas chromatography Mass spectrometry (GC-MS) | Capacitive-voltage and capacitive- frequency method | Electrical impedance spectroscopy (EIS) |
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| Parameters determined | (i) Phase shifts
(ii) Cancer index | (i) Young’s modulus
(ii) Single cell elasticity | At 2 different pH values (pH 7 and pH 2):
(i) Volatile profiling
(ii) Metabolomic profiling
(iii) Effect size
(iv) Percentage of variation | (i) Polarization
(ii) Dielectric properties | Resistance and capacitance at 4 phases:
(i)Growth
(ii) Confluence
(iii) Wounding
(iv) Healing |
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| Analysis | Bird's eye view of phase-shift analysis | Hertz–Sneddon model | Statistical analysis: PCA and PLS-DA | Capacitive modelling | Feature analysis and selection with linear discriminant analysis |
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| Pros | (i) Less time consumption
(ii) NN are flexible and used for both regression and classification problems
(iii) Can model with nonlinear data with large number of inputs
(iv) Once prepared, the predictions are fast | (i) Resolution: −0.5–5 nm depth and −0.2–10.0 nm (lateral)
(ii) For conductive and nonconductive
(iii) Can be used for nanocrystals and nanotubes as well | (i) Suitable for certain analytes
(ii) Many well-established protocols
(iii) Faster method development | (i) Fast
(ii) Sensitive
(iii) No preprocessing steps | (i) Consistent results
(ii) Nondestructive techniques, hence less material is required
(iii) Cell sorting
(iv) High resolution |
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| Cons | (i) Histograms of different cells are overlapping; hence, sensitivity and specificity needs to improve
(ii) The tableland and cone shapes are considered as the distinctive shape of normal and cancer cells, which is not a promising feature | (i) Its clinical use needs more systematic studies
(ii) Structural complexity and heterogeneity of tumor questions the relevance of elasticity measurements | (i) The integration of volatile organic compounds (VOCs) in specific metabolic pathways is still very difficult and needs more studies | (i) Capacitive values may vary from one investigational setup to another
(ii) Single cell analysis is required to produce more precise results for the intrinsic properties of cells | (i) To determine cancer cells in coculture inside a single well containing a set of spatially distributed microelectrodes |
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| Processing time | Few hours | Few hours to one day | Few days: as VOCs take at least 2 days | Few minutes | Few days |
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| Reliability | Less reliable | Less reliable due to the following:
(i) Small scan image size and restricted speed
(ii) Slow rate of scanning leads to thermal drift
(iii) Images affected by hysteresis property of the piezoelectric material | Moderate reliable: as it does not produce accurate results for all cell lines | Yes | Yes |
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| Errors | Error in case of contamination only | — | Separate errors for each sample | Error of 5% | Error of 4.5% |
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