Universal pictures: A lithophane codex helps teenagers with blindness visualize nanoscopic systems

Abstract

People with blindness have limited access to the high-resolution graphical data and imagery of science. Here, a lithophane codex is reported. Its pages display tactile and optical readouts for universal visualization of data by persons with or without eyesight. Prototype codices illustrated microscopy of butterfly chitin-from N-acetylglucosamine monomer to fibril, scale, and whole insect-and were given to high schoolers from the Texas School for the Blind and Visually Impaired. Lithophane graphics of Fischer-Spier esterification reactions and electron micrographs of biological cells were also 3D-printed, along with x-ray structures of proteins (as millimeter-scale 3D models). Students with blindness could visualize (describe, recall, distinguish) these systems-for the first time-at the same resolution as sighted peers (average accuracy = 88%). Tactile visualization occurred alongside laboratory training, synthesis, and mentoring by chemists with blindness, resulting in increased student interest and sense of belonging in science.

Fig. 1.. Conventional tactile graphics used to teach organic chemistry to a student with blindness.

These graphics are Braille transcriptions from Organic Chemistry by Brown, Foote, and Iverson, 4th Edition. (A) Swell form (thermo-form) tactile graphics depicting a Meisenheimer complex. (B) Plastic embossing graphic depicting (1R, 3S)-3-methylcyclohexan-1-ol. (C) Magnification of a chemical structure in plastic embossing. (D) Partial structure of a cyclic compound (the rest of the structure was continued on a next page due to size constraints). (E) Hybrid bond-line and Braille structure of nylon. (F) Resonance of an allylic carbocation structure. Note that although graphics are from the same textbook, three different indicators are used for a single covalent chemical bond (e.g., a raised line or Braille positions 1, 2, and 3). The plastic embossing uses a third indicator for single bonds: a string of dots.

Fig. 2.. Lithophanes and 3D models of microscopic and nanoscopic imagery made with an inexpensive 3D printer.

(A) Top row: digital images of electron and fluorescence micrographs; middle row: frontlit lithophanes of micrographs from the top panel; bottom row: backlit lithophanes of micrographs. From left to right: scanning electron micrograph of a jumping spider (scale bar, 500 μm), transmission electron micrograph of a plant cell showing chloroplast and mitochondria (scale bar, 1 μm). Labels for plant cell: (i) vacuole, (ii) intracellular space, (iii) nucleus with DNA, (iv) peroxisome, (v) chloroplast, and (vi) mitochondria. (B) 3D-printed cartoon micro-model of an α helix from the NIH 3D print repository (indole side chain of tryptophan is shown). (C) 3D-printed micro-model of a β-barrel protein [green fluorescent protein (GFP)] from the NIH 3D print repository.

Fig. 3.. Limitations of swell form graphics in portraying imagery from high-resolution electron microscopy compared to lithophane graphics.

(A) Lithophane (top) and swell form (bottom) graphics of a single butterfly scale micrograph captured with an SEM. Certain areas of chitin fibrils failed to swell. Further, the decrease in resolution of the swell form is apparent. While the lithophane depicts details in the chitin fibrils of the scale, the swell form paper melts it together, rendering it unresolvable. (B) Lithophane (top) and swell form (bottom) graphics of a plant cell capture with a TEM. The swell form paper shows a complete failure to swell, except for small spots of the chloroplast. The lithophane, in contrast, provides a high-resolution tactile and visual readout of all parts of the master image. (C) Paper (left), swell form paper (middle), and lithophane (right) graphics of a butterfly model. Upon thermal swelling, resolution was lost and the ink “popcorned” in the swell form image. (D) Swell form (left) and lithophane (right) graphics of a micrograph of chitin scales of a butterfly. After thermal swelling, chitin scales failed to swell completely.

Fig. 4.. Lithophane graphics of five Fischer-Spier reactions between alcohol and carboxylic acid reagents and their ester products.

(A) Lithophane showing frontlit (left) and backlit (right) esterification of methanol and salicylic acid. (B) Frontlit lithophanes of reactions for ethyl propanoate (top-left), isoamyl acetate (top-right), butyl butanoate (bottom-left), and ethyl decadienoate (bottom-right). (C) Tactile dimensions of lithophane graphics. (D) In contrast, swell form graphics of the same image present with shallow maximal protuberance (i.e., 0.6 to 0.7 mm off the surface of the paper).

Fig. 5.. Visualization of bond-line structures from lithophanes in Fig. 4 by high school students with blindness or low vision.

(A) Fischer-Spier esterification products and reactants for each ester synthesized. (B) Student answers to counting queries for the number of carbons and (C) the number of double bonds in each molecule. Closed circle denotes control data, carried out by an undergraduate chemistry student with blindness using swell form images of each lithophane in Fig. 4.

Fig. 6.. Lithophane codex depicting chitin in butterflies: From chitin monomer to complete insect.

(A) The lithophane booklet [pages shown in (B)] bound with binder rings, containing scanning electron micrographs of butterfly wings in lithophane format. (B) Page 1: frontlit (top) and backlit (bottom) lithophane of a butterfly; scale bar, 2 cm. Page 2: frontlit (top) and backlit (middle) lithophane of scales of a butterfly wing; scale bar, 100 μm. Page 3: frontlit (top) and backlit (bottom) lithophane of a single scale of a butterfly wing; scale bar, 40 μm. Page 4: frontlit (top) and backlit (bottom) lithophane of chitin fibrils; scale bar, 10 μm. Page 5: frontlit (top) and backlit (bottom) lithophane of a chitin monomer; scale bar, 2 Å. (C) Number of layers of chitin scales from page 2 detected by high schoolers with blindness or low vision. Closed circle denotes control carried out by an undergraduate chemistry student with blindness using swell form images.

Fig. 7.. A universal lithophane codex and Rolodex depicting amino acid structures at physiological pH.

(A) A codex of lithophanes depicting structures and names of all essential amino acids with pK_a (where K_a is the acid dissociation constant) values and physiological protonation sates. (B) The maximum number (n) of lithophanes in a codex can be expressed as 0.85d = n(w), where d is the diameter of binder and w is the lithophane width. (C) A rotary file (i.e., “Rolodex”) of lithophanes depicting chemical structures of amino acids. Custom legs were added to this commercially available Rolodex to accommodate larger lithophanes. These codices are intended not only to make print or digital data accessible but also to organize data that are presented in sequence such as during a research presentation or lecture.

Fig. 8.. Tactile recall of allosteric (shape-shifting) proteins by high schoolers and PhD chemists with blindness or low vision.

(A) Micro-models of atomic structures from the PDB. Eight micro-models provided to test manual tactile distinction from the central study protein (i.e., recall accuracy in identifying the study protein). The control cohort consisted of PhD chemists with blindness, examining the same model structures. (B) List of student response to the question: Is this protein the study protein? Recall accuracy is listed on the right for each protein query. (C) Recall accuracy for protein models and their geometric dissimilarity compared to the study protein. Closed circle denotes scores for PhD chemists with blindness (who scored 100% on each model regardless of its geometric dissimilarity). (D) Relative size of the micro-models; scale bar, 20 mm.

Fig. 9.. Attitudes of high schoolers with blindness toward chemistry after a 3-day program on learning tactile visualization and laboratory tools.

*During the focus group, some students mentioned that their interest in chemistry, in learning science in college, or in pursuing a science career could not increase as they already had a very high interest in chemistry, in learning science, or in having a career in science before attending the program. †During the focus group, some students expressed that they did not have an increase in interest for having a science career since they were already maximally interested in having a science career (“ceiling” effect), already knew of a different career path they wanted to follow (and then stated that this program still made them more interested in chemistry), or felt like it was too soon to know what careers they would be interested in pursuing.