Evaluation of optical clearing with the combined liquid paraffin and glycerol mixture

Abstract

By scanning biological tissues in vivo and in vitro with optical coherence tomography, it is found that liquid paraffin can enhance the percutaneous penetration of glycerol in deep layers of tissue and take synergistically optical clearing effect with glycerol. It is shown from experimental results that 30% - 50% liquid paraffin glycerol solutions have the best enhancement effect. Considering the refractive index of liquid paraffin and its medicinal value, we think liquid paraffin will play an important role in optical clearing as the penetration enhancer of glycerol in future clinical research.

Keywords: (110.0113) Imaging through turbid media; (170.3880) Medical and biological imaging; (170.4500) Optical coherence tomography; (170.6930) Tissue.

Fig. 1

Ratios of RIR with and without applying the mixed solution. Y-axis represents the ratio of RIR, and X-axis represents the volume fraction of liquid paraffin in the mixed solution.

Fig. 2

The thickness variation of rat skin with time elapsing by applying the mixed agents of different concentrations. Y-axis represents the reduced thickness, and X-axis represents scanning time.

Fig. 3

Ratios of RIR of rat skin with time elapsing at 30%, 40% and 50% concentrations. (a) is the results at 300 µm interval, (b) is the results at 500 µm interval. Error bars depict the maximum and minimum of different samples at 40% concentration.

Fig. 4

A group of OCT images of rat skin. (a) OCT image without the agent, (b) 10 min, (c) 20 min, (d) 30 min, and (e) 40 min OCT images after topical application of 40% liquid paraffin glycerol solution on the same area, respectively.

Fig. 5

Intensity of OCT signals with scanning depth in Fig. 4. (a) is the average intensity in a region shown in the yellow rectangle of Fig. 4(a). (b) is the intensity of an arbitrarily selected position shown in the yellow line in Fig. 4(a).

Fig. 6

Ratios of RIR of human finger with time elapsing at 30%, 40% and 50% concentrations. (a) is the results at 500 µm interval, (b) is the results at 700 µm interval.

Fig. 7

OCT images of human finger. (a) an OCT image without the agent, (b) 5 min, (c) 10 min, (d) 15 min, (e) 20 min, (f) 25 min and (g) 30min OCT images after topical application of 30% liquid paraffin glycerol solution on the same area, respectively.