Starch in Polymers Technology

Starch-Based Biological Microlasers

“…After 12 h of freeze-drying under high vacuum at −50 °C, we collected the final well-defined DS products. The X-ray diffraction (XRD) pattern (Figure B) of FD DS contains a series of peaks at 15, 17, 18, and 23° (the XRD pattern of FD DS is in agreement with that of A-type starches), which are completely different in comparison with those (peaks at 5.6, 17, 22, and 24°) of B-type native DS . It is worth mentioning that the percentage of crystallinity of the FD DS is about 60% of that of the native DS according to the results calculated from the ratio of the total peak area to the total diffraction area (Figure S8).…”

“…This structure-related optical behavior boosts the development of multifarious optical sensors with WGM resonators. As a kind of natural microsphere resonator, starch granules show distinct structural transformation in response to temperature, acid–base, enzyme, etc . , By controllably inducing the structural transformation, the lasing properties would be modulated because of the structure-sensitive refractive index. These obtained structure-related optical actions will be helpful for the development of the application in optical biodetection.…”

“…This distinct content of crystal water will highly influence the type of packing pattern of the double helices and the phase transition. Particularly, B-type potato starch would transform to A-type phase via dehydration (Figure A) . Here, freeze-drying (FD) was selected to initiate the structural transformation because this method has little effect on the dye content as well as the external morphology (Figure S7).…”

“…The abundant hydroxyl groups and helical structures endow starch polymers with the ability to adsorb many functional substances, including iodine ions, metal ions, and organic dyes. These host–guest systems can be used as functional materials for optical devices. , Depending on the source of starch, starch granules have the appearance of sphere, ellipsoidal, or polygonal shapes with characteristic sizes ranging from hundreds of nanometers to 150 μm. , These starches, especially the natural spherical or ellipsoidal microgranule, would act as whispering gallery mode (WGM) resonators of high quality to provide sufficient optical gain for lasing. , These starch-based biolasers would avoid the complexity and bulkiness resulting from the mirror-like cavities, providing an interesting complement to earlier WGM biolasers within living cells. , Moreover, the starches can respond to environmental variations in terms of structural transformation, which might change the optical properties and act as a signal for the detection of tiny structural variations induced by external stimuli.…”

“…16,17 Depending on the source of starch, starch granules have the appearance of sphere, ellipsoidal, or polygonal shapes with characteristic sizes ranging from hundreds of nanometers to 150 μm. 15,18 These starches, especially the natural spherical or ellipsoidal microgranule, would act as whispering gallery mode (WGM) resonators of high quality to provide sufficient optical gain for lasing. 19,20 These starch-based biolasers would avoid the complexity and bulkiness resulting from the mirror-like cavities, providing an interesting complement to earlier WGM biolasers within living cells.…”